linux/drivers/i2c/i2c-core-base.c
Javier Martinez Canillas f4b17a14fa i2c: core: Make comment about I2C table requirement to reflect the code
I2C drivers were required to have an I2C device ID table even if were for
devices that would only be registered using a specific firmware interface
(e.g: OF or ACPI).

But commit da10c06a04 ("i2c: Make I2C ID tables non-mandatory for DT'ed
devices") changed the I2C core to relax the requirement and allow drivers
to avoid defining this table.

Unfortunately it only took into account drivers for OF-only devices and
forgot about ACPI-only ones, and this was fixed by commit c64ffff7a9
("i2c: core: Allow empty id_table in ACPI case as well").

But the latter didn't update the original comment, so it doesn't reflect
what the code does now.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-08-14 21:33:46 +02:00

2247 lines
60 KiB
C

/*
* Linux I2C core
*
* Copyright (C) 1995-99 Simon G. Vogl
* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
* Mux support by Rodolfo Giometti <giometti@enneenne.com> and
* Michael Lawnick <michael.lawnick.ext@nsn.com>
*
* Copyright (C) 2013-2017 Wolfram Sang <wsa@the-dreams.de>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
*/
#define pr_fmt(fmt) "i2c-core: " fmt
#include <dt-bindings/i2c/i2c.h>
#include <linux/acpi.h>
#include <linux/clk/clk-conf.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/gpio.h>
#include <linux/i2c.h>
#include <linux/idr.h>
#include <linux/init.h>
#include <linux/irqflags.h>
#include <linux/jump_label.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of_device.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
#include <linux/pm_wakeirq.h>
#include <linux/property.h>
#include <linux/rwsem.h>
#include <linux/slab.h>
#include "i2c-core.h"
#define CREATE_TRACE_POINTS
#include <trace/events/i2c.h>
#define I2C_ADDR_OFFSET_TEN_BIT 0xa000
#define I2C_ADDR_OFFSET_SLAVE 0x1000
#define I2C_ADDR_7BITS_MAX 0x77
#define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1)
/*
* core_lock protects i2c_adapter_idr, and guarantees that device detection,
* deletion of detected devices, and attach_adapter calls are serialized
*/
static DEFINE_MUTEX(core_lock);
static DEFINE_IDR(i2c_adapter_idr);
static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
static bool is_registered;
int i2c_transfer_trace_reg(void)
{
static_key_slow_inc(&i2c_trace_msg);
return 0;
}
void i2c_transfer_trace_unreg(void)
{
static_key_slow_dec(&i2c_trace_msg);
}
const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
const struct i2c_client *client)
{
if (!(id && client))
return NULL;
while (id->name[0]) {
if (strcmp(client->name, id->name) == 0)
return id;
id++;
}
return NULL;
}
EXPORT_SYMBOL_GPL(i2c_match_id);
static int i2c_device_match(struct device *dev, struct device_driver *drv)
{
struct i2c_client *client = i2c_verify_client(dev);
struct i2c_driver *driver;
/* Attempt an OF style match */
if (i2c_of_match_device(drv->of_match_table, client))
return 1;
/* Then ACPI style match */
if (acpi_driver_match_device(dev, drv))
return 1;
driver = to_i2c_driver(drv);
/* Finally an I2C match */
if (i2c_match_id(driver->id_table, client))
return 1;
return 0;
}
static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
{
struct i2c_client *client = to_i2c_client(dev);
int rc;
rc = acpi_device_uevent_modalias(dev, env);
if (rc != -ENODEV)
return rc;
return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
}
/* i2c bus recovery routines */
static int get_scl_gpio_value(struct i2c_adapter *adap)
{
return gpio_get_value(adap->bus_recovery_info->scl_gpio);
}
static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
{
gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
}
static int get_sda_gpio_value(struct i2c_adapter *adap)
{
return gpio_get_value(adap->bus_recovery_info->sda_gpio);
}
static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap)
{
struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
struct device *dev = &adap->dev;
int ret = 0;
ret = gpio_request_one(bri->scl_gpio, GPIOF_OPEN_DRAIN |
GPIOF_OUT_INIT_HIGH, "i2c-scl");
if (ret) {
dev_warn(dev, "Can't get SCL gpio: %d\n", bri->scl_gpio);
return ret;
}
if (bri->get_sda) {
if (gpio_request_one(bri->sda_gpio, GPIOF_IN, "i2c-sda")) {
/* work without SDA polling */
dev_warn(dev, "Can't get SDA gpio: %d. Not using SDA polling\n",
bri->sda_gpio);
bri->get_sda = NULL;
}
}
return ret;
}
static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap)
{
struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
if (bri->get_sda)
gpio_free(bri->sda_gpio);
gpio_free(bri->scl_gpio);
}
/*
* We are generating clock pulses. ndelay() determines durating of clk pulses.
* We will generate clock with rate 100 KHz and so duration of both clock levels
* is: delay in ns = (10^6 / 100) / 2
*/
#define RECOVERY_NDELAY 5000
#define RECOVERY_CLK_CNT 9
static int i2c_generic_recovery(struct i2c_adapter *adap)
{
struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
int i = 0, val = 1, ret = 0;
if (bri->prepare_recovery)
bri->prepare_recovery(adap);
bri->set_scl(adap, val);
ndelay(RECOVERY_NDELAY);
/*
* By this time SCL is high, as we need to give 9 falling-rising edges
*/
while (i++ < RECOVERY_CLK_CNT * 2) {
if (val) {
/* Break if SDA is high */
if (bri->get_sda && bri->get_sda(adap))
break;
/* SCL shouldn't be low here */
if (!bri->get_scl(adap)) {
dev_err(&adap->dev,
"SCL is stuck low, exit recovery\n");
ret = -EBUSY;
break;
}
}
val = !val;
bri->set_scl(adap, val);
ndelay(RECOVERY_NDELAY);
}
if (bri->unprepare_recovery)
bri->unprepare_recovery(adap);
return ret;
}
int i2c_generic_scl_recovery(struct i2c_adapter *adap)
{
return i2c_generic_recovery(adap);
}
EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
int i2c_generic_gpio_recovery(struct i2c_adapter *adap)
{
int ret;
ret = i2c_get_gpios_for_recovery(adap);
if (ret)
return ret;
ret = i2c_generic_recovery(adap);
i2c_put_gpios_for_recovery(adap);
return ret;
}
EXPORT_SYMBOL_GPL(i2c_generic_gpio_recovery);
int i2c_recover_bus(struct i2c_adapter *adap)
{
if (!adap->bus_recovery_info)
return -EOPNOTSUPP;
dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
return adap->bus_recovery_info->recover_bus(adap);
}
EXPORT_SYMBOL_GPL(i2c_recover_bus);
static void i2c_init_recovery(struct i2c_adapter *adap)
{
struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
char *err_str;
if (!bri)
return;
if (!bri->recover_bus) {
err_str = "no recover_bus() found";
goto err;
}
/* Generic GPIO recovery */
if (bri->recover_bus == i2c_generic_gpio_recovery) {
if (!gpio_is_valid(bri->scl_gpio)) {
err_str = "invalid SCL gpio";
goto err;
}
if (gpio_is_valid(bri->sda_gpio))
bri->get_sda = get_sda_gpio_value;
else
bri->get_sda = NULL;
bri->get_scl = get_scl_gpio_value;
bri->set_scl = set_scl_gpio_value;
} else if (bri->recover_bus == i2c_generic_scl_recovery) {
/* Generic SCL recovery */
if (!bri->set_scl || !bri->get_scl) {
err_str = "no {get|set}_scl() found";
goto err;
}
}
return;
err:
dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
adap->bus_recovery_info = NULL;
}
static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
{
struct i2c_adapter *adap = client->adapter;
unsigned int irq;
if (!adap->host_notify_domain)
return -ENXIO;
if (client->flags & I2C_CLIENT_TEN)
return -EINVAL;
irq = irq_find_mapping(adap->host_notify_domain, client->addr);
if (!irq)
irq = irq_create_mapping(adap->host_notify_domain,
client->addr);
return irq > 0 ? irq : -ENXIO;
}
static int i2c_device_probe(struct device *dev)
{
struct i2c_client *client = i2c_verify_client(dev);
struct i2c_driver *driver;
int status;
if (!client)
return 0;
driver = to_i2c_driver(dev->driver);
if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
int irq = -ENOENT;
if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
dev_dbg(dev, "Using Host Notify IRQ\n");
irq = i2c_smbus_host_notify_to_irq(client);
} else if (dev->of_node) {
irq = of_irq_get_byname(dev->of_node, "irq");
if (irq == -EINVAL || irq == -ENODATA)
irq = of_irq_get(dev->of_node, 0);
} else if (ACPI_COMPANION(dev)) {
irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
}
if (irq == -EPROBE_DEFER)
return irq;
if (irq < 0)
irq = 0;
client->irq = irq;
}
/*
* An I2C ID table is not mandatory, if and only if, a suitable OF
* or ACPI ID table is supplied for the probing device.
*/
if (!driver->id_table &&
!i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
!i2c_of_match_device(dev->driver->of_match_table, client))
return -ENODEV;
if (client->flags & I2C_CLIENT_WAKE) {
int wakeirq = -ENOENT;
if (dev->of_node) {
wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
if (wakeirq == -EPROBE_DEFER)
return wakeirq;
}
device_init_wakeup(&client->dev, true);
if (wakeirq > 0 && wakeirq != client->irq)
status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
else if (client->irq > 0)
status = dev_pm_set_wake_irq(dev, client->irq);
else
status = 0;
if (status)
dev_warn(&client->dev, "failed to set up wakeup irq\n");
}
dev_dbg(dev, "probe\n");
status = of_clk_set_defaults(dev->of_node, false);
if (status < 0)
goto err_clear_wakeup_irq;
status = dev_pm_domain_attach(&client->dev, true);
if (status == -EPROBE_DEFER)
goto err_clear_wakeup_irq;
/*
* When there are no more users of probe(),
* rename probe_new to probe.
*/
if (driver->probe_new)
status = driver->probe_new(client);
else if (driver->probe)
status = driver->probe(client,
i2c_match_id(driver->id_table, client));
else
status = -EINVAL;
if (status)
goto err_detach_pm_domain;
return 0;
err_detach_pm_domain:
dev_pm_domain_detach(&client->dev, true);
err_clear_wakeup_irq:
dev_pm_clear_wake_irq(&client->dev);
device_init_wakeup(&client->dev, false);
return status;
}
static int i2c_device_remove(struct device *dev)
{
struct i2c_client *client = i2c_verify_client(dev);
struct i2c_driver *driver;
int status = 0;
if (!client || !dev->driver)
return 0;
driver = to_i2c_driver(dev->driver);
if (driver->remove) {
dev_dbg(dev, "remove\n");
status = driver->remove(client);
}
dev_pm_domain_detach(&client->dev, true);
dev_pm_clear_wake_irq(&client->dev);
device_init_wakeup(&client->dev, false);
return status;
}
static void i2c_device_shutdown(struct device *dev)
{
struct i2c_client *client = i2c_verify_client(dev);
struct i2c_driver *driver;
if (!client || !dev->driver)
return;
driver = to_i2c_driver(dev->driver);
if (driver->shutdown)
driver->shutdown(client);
}
static void i2c_client_dev_release(struct device *dev)
{
kfree(to_i2c_client(dev));
}
static ssize_t
show_name(struct device *dev, struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
}
static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
static ssize_t
show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
{
struct i2c_client *client = to_i2c_client(dev);
int len;
len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
if (len != -ENODEV)
return len;
return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
}
static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
static struct attribute *i2c_dev_attrs[] = {
&dev_attr_name.attr,
/* modalias helps coldplug: modprobe $(cat .../modalias) */
&dev_attr_modalias.attr,
NULL
};
ATTRIBUTE_GROUPS(i2c_dev);
struct bus_type i2c_bus_type = {
.name = "i2c",
.match = i2c_device_match,
.probe = i2c_device_probe,
.remove = i2c_device_remove,
.shutdown = i2c_device_shutdown,
};
EXPORT_SYMBOL_GPL(i2c_bus_type);
struct device_type i2c_client_type = {
.groups = i2c_dev_groups,
.uevent = i2c_device_uevent,
.release = i2c_client_dev_release,
};
EXPORT_SYMBOL_GPL(i2c_client_type);
/**
* i2c_verify_client - return parameter as i2c_client, or NULL
* @dev: device, probably from some driver model iterator
*
* When traversing the driver model tree, perhaps using driver model
* iterators like @device_for_each_child(), you can't assume very much
* about the nodes you find. Use this function to avoid oopses caused
* by wrongly treating some non-I2C device as an i2c_client.
*/
struct i2c_client *i2c_verify_client(struct device *dev)
{
return (dev->type == &i2c_client_type)
? to_i2c_client(dev)
: NULL;
}
EXPORT_SYMBOL(i2c_verify_client);
/* Return a unique address which takes the flags of the client into account */
static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
{
unsigned short addr = client->addr;
/* For some client flags, add an arbitrary offset to avoid collisions */
if (client->flags & I2C_CLIENT_TEN)
addr |= I2C_ADDR_OFFSET_TEN_BIT;
if (client->flags & I2C_CLIENT_SLAVE)
addr |= I2C_ADDR_OFFSET_SLAVE;
return addr;
}
/* This is a permissive address validity check, I2C address map constraints
* are purposely not enforced, except for the general call address. */
int i2c_check_addr_validity(unsigned addr, unsigned short flags)
{
if (flags & I2C_CLIENT_TEN) {
/* 10-bit address, all values are valid */
if (addr > 0x3ff)
return -EINVAL;
} else {
/* 7-bit address, reject the general call address */
if (addr == 0x00 || addr > 0x7f)
return -EINVAL;
}
return 0;
}
/* And this is a strict address validity check, used when probing. If a
* device uses a reserved address, then it shouldn't be probed. 7-bit
* addressing is assumed, 10-bit address devices are rare and should be
* explicitly enumerated. */
int i2c_check_7bit_addr_validity_strict(unsigned short addr)
{
/*
* Reserved addresses per I2C specification:
* 0x00 General call address / START byte
* 0x01 CBUS address
* 0x02 Reserved for different bus format
* 0x03 Reserved for future purposes
* 0x04-0x07 Hs-mode master code
* 0x78-0x7b 10-bit slave addressing
* 0x7c-0x7f Reserved for future purposes
*/
if (addr < 0x08 || addr > 0x77)
return -EINVAL;
return 0;
}
static int __i2c_check_addr_busy(struct device *dev, void *addrp)
{
struct i2c_client *client = i2c_verify_client(dev);
int addr = *(int *)addrp;
if (client && i2c_encode_flags_to_addr(client) == addr)
return -EBUSY;
return 0;
}
/* walk up mux tree */
static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
{
struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
int result;
result = device_for_each_child(&adapter->dev, &addr,
__i2c_check_addr_busy);
if (!result && parent)
result = i2c_check_mux_parents(parent, addr);
return result;
}
/* recurse down mux tree */
static int i2c_check_mux_children(struct device *dev, void *addrp)
{
int result;
if (dev->type == &i2c_adapter_type)
result = device_for_each_child(dev, addrp,
i2c_check_mux_children);
else
result = __i2c_check_addr_busy(dev, addrp);
return result;
}
static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
{
struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
int result = 0;
if (parent)
result = i2c_check_mux_parents(parent, addr);
if (!result)
result = device_for_each_child(&adapter->dev, &addr,
i2c_check_mux_children);
return result;
}
/**
* i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
* @adapter: Target I2C bus segment
* @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
* locks only this branch in the adapter tree
*/
static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
unsigned int flags)
{
rt_mutex_lock(&adapter->bus_lock);
}
/**
* i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
* @adapter: Target I2C bus segment
* @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
* trylocks only this branch in the adapter tree
*/
static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
unsigned int flags)
{
return rt_mutex_trylock(&adapter->bus_lock);
}
/**
* i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
* @adapter: Target I2C bus segment
* @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
* unlocks only this branch in the adapter tree
*/
static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
unsigned int flags)
{
rt_mutex_unlock(&adapter->bus_lock);
}
static void i2c_dev_set_name(struct i2c_adapter *adap,
struct i2c_client *client)
{
struct acpi_device *adev = ACPI_COMPANION(&client->dev);
if (adev) {
dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
return;
}
dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
i2c_encode_flags_to_addr(client));
}
static int i2c_dev_irq_from_resources(const struct resource *resources,
unsigned int num_resources)
{
struct irq_data *irqd;
int i;
for (i = 0; i < num_resources; i++) {
const struct resource *r = &resources[i];
if (resource_type(r) != IORESOURCE_IRQ)
continue;
if (r->flags & IORESOURCE_BITS) {
irqd = irq_get_irq_data(r->start);
if (!irqd)
break;
irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
}
return r->start;
}
return 0;
}
/**
* i2c_new_device - instantiate an i2c device
* @adap: the adapter managing the device
* @info: describes one I2C device; bus_num is ignored
* Context: can sleep
*
* Create an i2c device. Binding is handled through driver model
* probe()/remove() methods. A driver may be bound to this device when we
* return from this function, or any later moment (e.g. maybe hotplugging will
* load the driver module). This call is not appropriate for use by mainboard
* initialization logic, which usually runs during an arch_initcall() long
* before any i2c_adapter could exist.
*
* This returns the new i2c client, which may be saved for later use with
* i2c_unregister_device(); or NULL to indicate an error.
*/
struct i2c_client *
i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
{
struct i2c_client *client;
int status;
client = kzalloc(sizeof *client, GFP_KERNEL);
if (!client)
return NULL;
client->adapter = adap;
client->dev.platform_data = info->platform_data;
if (info->archdata)
client->dev.archdata = *info->archdata;
client->flags = info->flags;
client->addr = info->addr;
client->irq = info->irq;
if (!client->irq)
client->irq = i2c_dev_irq_from_resources(info->resources,
info->num_resources);
strlcpy(client->name, info->type, sizeof(client->name));
status = i2c_check_addr_validity(client->addr, client->flags);
if (status) {
dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
goto out_err_silent;
}
/* Check for address business */
status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
if (status)
goto out_err;
client->dev.parent = &client->adapter->dev;
client->dev.bus = &i2c_bus_type;
client->dev.type = &i2c_client_type;
client->dev.of_node = info->of_node;
client->dev.fwnode = info->fwnode;
i2c_dev_set_name(adap, client);
if (info->properties) {
status = device_add_properties(&client->dev, info->properties);
if (status) {
dev_err(&adap->dev,
"Failed to add properties to client %s: %d\n",
client->name, status);
goto out_err;
}
}
status = device_register(&client->dev);
if (status)
goto out_free_props;
dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
client->name, dev_name(&client->dev));
return client;
out_free_props:
if (info->properties)
device_remove_properties(&client->dev);
out_err:
dev_err(&adap->dev,
"Failed to register i2c client %s at 0x%02x (%d)\n",
client->name, client->addr, status);
out_err_silent:
kfree(client);
return NULL;
}
EXPORT_SYMBOL_GPL(i2c_new_device);
/**
* i2c_unregister_device - reverse effect of i2c_new_device()
* @client: value returned from i2c_new_device()
* Context: can sleep
*/
void i2c_unregister_device(struct i2c_client *client)
{
if (client->dev.of_node)
of_node_clear_flag(client->dev.of_node, OF_POPULATED);
if (ACPI_COMPANION(&client->dev))
acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
device_unregister(&client->dev);
}
EXPORT_SYMBOL_GPL(i2c_unregister_device);
static const struct i2c_device_id dummy_id[] = {
{ "dummy", 0 },
{ },
};
static int dummy_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
return 0;
}
static int dummy_remove(struct i2c_client *client)
{
return 0;
}
static struct i2c_driver dummy_driver = {
.driver.name = "dummy",
.probe = dummy_probe,
.remove = dummy_remove,
.id_table = dummy_id,
};
/**
* i2c_new_dummy - return a new i2c device bound to a dummy driver
* @adapter: the adapter managing the device
* @address: seven bit address to be used
* Context: can sleep
*
* This returns an I2C client bound to the "dummy" driver, intended for use
* with devices that consume multiple addresses. Examples of such chips
* include various EEPROMS (like 24c04 and 24c08 models).
*
* These dummy devices have two main uses. First, most I2C and SMBus calls
* except i2c_transfer() need a client handle; the dummy will be that handle.
* And second, this prevents the specified address from being bound to a
* different driver.
*
* This returns the new i2c client, which should be saved for later use with
* i2c_unregister_device(); or NULL to indicate an error.
*/
struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
{
struct i2c_board_info info = {
I2C_BOARD_INFO("dummy", address),
};
return i2c_new_device(adapter, &info);
}
EXPORT_SYMBOL_GPL(i2c_new_dummy);
/**
* i2c_new_secondary_device - Helper to get the instantiated secondary address
* and create the associated device
* @client: Handle to the primary client
* @name: Handle to specify which secondary address to get
* @default_addr: Used as a fallback if no secondary address was specified
* Context: can sleep
*
* I2C clients can be composed of multiple I2C slaves bound together in a single
* component. The I2C client driver then binds to the master I2C slave and needs
* to create I2C dummy clients to communicate with all the other slaves.
*
* This function creates and returns an I2C dummy client whose I2C address is
* retrieved from the platform firmware based on the given slave name. If no
* address is specified by the firmware default_addr is used.
*
* On DT-based platforms the address is retrieved from the "reg" property entry
* cell whose "reg-names" value matches the slave name.
*
* This returns the new i2c client, which should be saved for later use with
* i2c_unregister_device(); or NULL to indicate an error.
*/
struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
const char *name,
u16 default_addr)
{
struct device_node *np = client->dev.of_node;
u32 addr = default_addr;
int i;
if (np) {
i = of_property_match_string(np, "reg-names", name);
if (i >= 0)
of_property_read_u32_index(np, "reg", i, &addr);
}
dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
return i2c_new_dummy(client->adapter, addr);
}
EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
/* ------------------------------------------------------------------------- */
/* I2C bus adapters -- one roots each I2C or SMBUS segment */
static void i2c_adapter_dev_release(struct device *dev)
{
struct i2c_adapter *adap = to_i2c_adapter(dev);
complete(&adap->dev_released);
}
unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
{
unsigned int depth = 0;
while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
depth++;
WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
"adapter depth exceeds lockdep subclass limit\n");
return depth;
}
EXPORT_SYMBOL_GPL(i2c_adapter_depth);
/*
* Let users instantiate I2C devices through sysfs. This can be used when
* platform initialization code doesn't contain the proper data for
* whatever reason. Also useful for drivers that do device detection and
* detection fails, either because the device uses an unexpected address,
* or this is a compatible device with different ID register values.
*
* Parameter checking may look overzealous, but we really don't want
* the user to provide incorrect parameters.
*/
static ssize_t
i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct i2c_adapter *adap = to_i2c_adapter(dev);
struct i2c_board_info info;
struct i2c_client *client;
char *blank, end;
int res;
memset(&info, 0, sizeof(struct i2c_board_info));
blank = strchr(buf, ' ');
if (!blank) {
dev_err(dev, "%s: Missing parameters\n", "new_device");
return -EINVAL;
}
if (blank - buf > I2C_NAME_SIZE - 1) {
dev_err(dev, "%s: Invalid device name\n", "new_device");
return -EINVAL;
}
memcpy(info.type, buf, blank - buf);
/* Parse remaining parameters, reject extra parameters */
res = sscanf(++blank, "%hi%c", &info.addr, &end);
if (res < 1) {
dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
return -EINVAL;
}
if (res > 1 && end != '\n') {
dev_err(dev, "%s: Extra parameters\n", "new_device");
return -EINVAL;
}
if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
info.flags |= I2C_CLIENT_TEN;
}
if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
info.flags |= I2C_CLIENT_SLAVE;
}
client = i2c_new_device(adap, &info);
if (!client)
return -EINVAL;
/* Keep track of the added device */
mutex_lock(&adap->userspace_clients_lock);
list_add_tail(&client->detected, &adap->userspace_clients);
mutex_unlock(&adap->userspace_clients_lock);
dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
info.type, info.addr);
return count;
}
static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
/*
* And of course let the users delete the devices they instantiated, if
* they got it wrong. This interface can only be used to delete devices
* instantiated by i2c_sysfs_new_device above. This guarantees that we
* don't delete devices to which some kernel code still has references.
*
* Parameter checking may look overzealous, but we really don't want
* the user to delete the wrong device.
*/
static ssize_t
i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct i2c_adapter *adap = to_i2c_adapter(dev);
struct i2c_client *client, *next;
unsigned short addr;
char end;
int res;
/* Parse parameters, reject extra parameters */
res = sscanf(buf, "%hi%c", &addr, &end);
if (res < 1) {
dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
return -EINVAL;
}
if (res > 1 && end != '\n') {
dev_err(dev, "%s: Extra parameters\n", "delete_device");
return -EINVAL;
}
/* Make sure the device was added through sysfs */
res = -ENOENT;
mutex_lock_nested(&adap->userspace_clients_lock,
i2c_adapter_depth(adap));
list_for_each_entry_safe(client, next, &adap->userspace_clients,
detected) {
if (i2c_encode_flags_to_addr(client) == addr) {
dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
"delete_device", client->name, client->addr);
list_del(&client->detected);
i2c_unregister_device(client);
res = count;
break;
}
}
mutex_unlock(&adap->userspace_clients_lock);
if (res < 0)
dev_err(dev, "%s: Can't find device in list\n",
"delete_device");
return res;
}
static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
i2c_sysfs_delete_device);
static struct attribute *i2c_adapter_attrs[] = {
&dev_attr_name.attr,
&dev_attr_new_device.attr,
&dev_attr_delete_device.attr,
NULL
};
ATTRIBUTE_GROUPS(i2c_adapter);
struct device_type i2c_adapter_type = {
.groups = i2c_adapter_groups,
.release = i2c_adapter_dev_release,
};
EXPORT_SYMBOL_GPL(i2c_adapter_type);
/**
* i2c_verify_adapter - return parameter as i2c_adapter or NULL
* @dev: device, probably from some driver model iterator
*
* When traversing the driver model tree, perhaps using driver model
* iterators like @device_for_each_child(), you can't assume very much
* about the nodes you find. Use this function to avoid oopses caused
* by wrongly treating some non-I2C device as an i2c_adapter.
*/
struct i2c_adapter *i2c_verify_adapter(struct device *dev)
{
return (dev->type == &i2c_adapter_type)
? to_i2c_adapter(dev)
: NULL;
}
EXPORT_SYMBOL(i2c_verify_adapter);
#ifdef CONFIG_I2C_COMPAT
static struct class_compat *i2c_adapter_compat_class;
#endif
static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
{
struct i2c_devinfo *devinfo;
down_read(&__i2c_board_lock);
list_for_each_entry(devinfo, &__i2c_board_list, list) {
if (devinfo->busnum == adapter->nr
&& !i2c_new_device(adapter,
&devinfo->board_info))
dev_err(&adapter->dev,
"Can't create device at 0x%02x\n",
devinfo->board_info.addr);
}
up_read(&__i2c_board_lock);
}
static int i2c_do_add_adapter(struct i2c_driver *driver,
struct i2c_adapter *adap)
{
/* Detect supported devices on that bus, and instantiate them */
i2c_detect(adap, driver);
/* Let legacy drivers scan this bus for matching devices */
if (driver->attach_adapter) {
dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
driver->driver.name);
dev_warn(&adap->dev,
"Please use another way to instantiate your i2c_client\n");
/* We ignore the return code; if it fails, too bad */
driver->attach_adapter(adap);
}
return 0;
}
static int __process_new_adapter(struct device_driver *d, void *data)
{
return i2c_do_add_adapter(to_i2c_driver(d), data);
}
static const struct i2c_lock_operations i2c_adapter_lock_ops = {
.lock_bus = i2c_adapter_lock_bus,
.trylock_bus = i2c_adapter_trylock_bus,
.unlock_bus = i2c_adapter_unlock_bus,
};
static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
{
struct irq_domain *domain = adap->host_notify_domain;
irq_hw_number_t hwirq;
if (!domain)
return;
for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
irq_dispose_mapping(irq_find_mapping(domain, hwirq));
irq_domain_remove(domain);
adap->host_notify_domain = NULL;
}
static int i2c_host_notify_irq_map(struct irq_domain *h,
unsigned int virq,
irq_hw_number_t hw_irq_num)
{
irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
return 0;
}
static const struct irq_domain_ops i2c_host_notify_irq_ops = {
.map = i2c_host_notify_irq_map,
};
static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
{
struct irq_domain *domain;
if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
return 0;
domain = irq_domain_create_linear(adap->dev.fwnode,
I2C_ADDR_7BITS_COUNT,
&i2c_host_notify_irq_ops, adap);
if (!domain)
return -ENOMEM;
adap->host_notify_domain = domain;
return 0;
}
/**
* i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
* I2C client.
* @adap: the adapter
* @addr: the I2C address of the notifying device
* Context: can't sleep
*
* Helper function to be called from an I2C bus driver's interrupt
* handler. It will schedule the Host Notify IRQ.
*/
int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
{
int irq;
if (!adap)
return -EINVAL;
irq = irq_find_mapping(adap->host_notify_domain, addr);
if (irq <= 0)
return -ENXIO;
generic_handle_irq(irq);
return 0;
}
EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
static int i2c_register_adapter(struct i2c_adapter *adap)
{
int res = -EINVAL;
/* Can't register until after driver model init */
if (WARN_ON(!is_registered)) {
res = -EAGAIN;
goto out_list;
}
/* Sanity checks */
if (WARN(!adap->name[0], "i2c adapter has no name"))
goto out_list;
if (!adap->algo) {
pr_err("adapter '%s': no algo supplied!\n", adap->name);
goto out_list;
}
if (!adap->lock_ops)
adap->lock_ops = &i2c_adapter_lock_ops;
rt_mutex_init(&adap->bus_lock);
rt_mutex_init(&adap->mux_lock);
mutex_init(&adap->userspace_clients_lock);
INIT_LIST_HEAD(&adap->userspace_clients);
/* Set default timeout to 1 second if not already set */
if (adap->timeout == 0)
adap->timeout = HZ;
/* register soft irqs for Host Notify */
res = i2c_setup_host_notify_irq_domain(adap);
if (res) {
pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
adap->name, res);
goto out_list;
}
dev_set_name(&adap->dev, "i2c-%d", adap->nr);
adap->dev.bus = &i2c_bus_type;
adap->dev.type = &i2c_adapter_type;
res = device_register(&adap->dev);
if (res) {
pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
goto out_list;
}
dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
pm_runtime_no_callbacks(&adap->dev);
pm_suspend_ignore_children(&adap->dev, true);
pm_runtime_enable(&adap->dev);
#ifdef CONFIG_I2C_COMPAT
res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
adap->dev.parent);
if (res)
dev_warn(&adap->dev,
"Failed to create compatibility class link\n");
#endif
i2c_init_recovery(adap);
/* create pre-declared device nodes */
of_i2c_register_devices(adap);
i2c_acpi_register_devices(adap);
i2c_acpi_install_space_handler(adap);
if (adap->nr < __i2c_first_dynamic_bus_num)
i2c_scan_static_board_info(adap);
/* Notify drivers */
mutex_lock(&core_lock);
bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
mutex_unlock(&core_lock);
return 0;
out_list:
mutex_lock(&core_lock);
idr_remove(&i2c_adapter_idr, adap->nr);
mutex_unlock(&core_lock);
return res;
}
/**
* __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
* @adap: the adapter to register (with adap->nr initialized)
* Context: can sleep
*
* See i2c_add_numbered_adapter() for details.
*/
static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
{
int id;
mutex_lock(&core_lock);
id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
mutex_unlock(&core_lock);
if (WARN(id < 0, "couldn't get idr"))
return id == -ENOSPC ? -EBUSY : id;
return i2c_register_adapter(adap);
}
/**
* i2c_add_adapter - declare i2c adapter, use dynamic bus number
* @adapter: the adapter to add
* Context: can sleep
*
* This routine is used to declare an I2C adapter when its bus number
* doesn't matter or when its bus number is specified by an dt alias.
* Examples of bases when the bus number doesn't matter: I2C adapters
* dynamically added by USB links or PCI plugin cards.
*
* When this returns zero, a new bus number was allocated and stored
* in adap->nr, and the specified adapter became available for clients.
* Otherwise, a negative errno value is returned.
*/
int i2c_add_adapter(struct i2c_adapter *adapter)
{
struct device *dev = &adapter->dev;
int id;
if (dev->of_node) {
id = of_alias_get_id(dev->of_node, "i2c");
if (id >= 0) {
adapter->nr = id;
return __i2c_add_numbered_adapter(adapter);
}
}
mutex_lock(&core_lock);
id = idr_alloc(&i2c_adapter_idr, adapter,
__i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
mutex_unlock(&core_lock);
if (WARN(id < 0, "couldn't get idr"))
return id;
adapter->nr = id;
return i2c_register_adapter(adapter);
}
EXPORT_SYMBOL(i2c_add_adapter);
/**
* i2c_add_numbered_adapter - declare i2c adapter, use static bus number
* @adap: the adapter to register (with adap->nr initialized)
* Context: can sleep
*
* This routine is used to declare an I2C adapter when its bus number
* matters. For example, use it for I2C adapters from system-on-chip CPUs,
* or otherwise built in to the system's mainboard, and where i2c_board_info
* is used to properly configure I2C devices.
*
* If the requested bus number is set to -1, then this function will behave
* identically to i2c_add_adapter, and will dynamically assign a bus number.
*
* If no devices have pre-been declared for this bus, then be sure to
* register the adapter before any dynamically allocated ones. Otherwise
* the required bus ID may not be available.
*
* When this returns zero, the specified adapter became available for
* clients using the bus number provided in adap->nr. Also, the table
* of I2C devices pre-declared using i2c_register_board_info() is scanned,
* and the appropriate driver model device nodes are created. Otherwise, a
* negative errno value is returned.
*/
int i2c_add_numbered_adapter(struct i2c_adapter *adap)
{
if (adap->nr == -1) /* -1 means dynamically assign bus id */
return i2c_add_adapter(adap);
return __i2c_add_numbered_adapter(adap);
}
EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
static void i2c_do_del_adapter(struct i2c_driver *driver,
struct i2c_adapter *adapter)
{
struct i2c_client *client, *_n;
/* Remove the devices we created ourselves as the result of hardware
* probing (using a driver's detect method) */
list_for_each_entry_safe(client, _n, &driver->clients, detected) {
if (client->adapter == adapter) {
dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
client->name, client->addr);
list_del(&client->detected);
i2c_unregister_device(client);
}
}
}
static int __unregister_client(struct device *dev, void *dummy)
{
struct i2c_client *client = i2c_verify_client(dev);
if (client && strcmp(client->name, "dummy"))
i2c_unregister_device(client);
return 0;
}
static int __unregister_dummy(struct device *dev, void *dummy)
{
struct i2c_client *client = i2c_verify_client(dev);
if (client)
i2c_unregister_device(client);
return 0;
}
static int __process_removed_adapter(struct device_driver *d, void *data)
{
i2c_do_del_adapter(to_i2c_driver(d), data);
return 0;
}
/**
* i2c_del_adapter - unregister I2C adapter
* @adap: the adapter being unregistered
* Context: can sleep
*
* This unregisters an I2C adapter which was previously registered
* by @i2c_add_adapter or @i2c_add_numbered_adapter.
*/
void i2c_del_adapter(struct i2c_adapter *adap)
{
struct i2c_adapter *found;
struct i2c_client *client, *next;
/* First make sure that this adapter was ever added */
mutex_lock(&core_lock);
found = idr_find(&i2c_adapter_idr, adap->nr);
mutex_unlock(&core_lock);
if (found != adap) {
pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
return;
}
i2c_acpi_remove_space_handler(adap);
/* Tell drivers about this removal */
mutex_lock(&core_lock);
bus_for_each_drv(&i2c_bus_type, NULL, adap,
__process_removed_adapter);
mutex_unlock(&core_lock);
/* Remove devices instantiated from sysfs */
mutex_lock_nested(&adap->userspace_clients_lock,
i2c_adapter_depth(adap));
list_for_each_entry_safe(client, next, &adap->userspace_clients,
detected) {
dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
client->addr);
list_del(&client->detected);
i2c_unregister_device(client);
}
mutex_unlock(&adap->userspace_clients_lock);
/* Detach any active clients. This can't fail, thus we do not
* check the returned value. This is a two-pass process, because
* we can't remove the dummy devices during the first pass: they
* could have been instantiated by real devices wishing to clean
* them up properly, so we give them a chance to do that first. */
device_for_each_child(&adap->dev, NULL, __unregister_client);
device_for_each_child(&adap->dev, NULL, __unregister_dummy);
#ifdef CONFIG_I2C_COMPAT
class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
adap->dev.parent);
#endif
/* device name is gone after device_unregister */
dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
pm_runtime_disable(&adap->dev);
i2c_host_notify_irq_teardown(adap);
/* wait until all references to the device are gone
*
* FIXME: This is old code and should ideally be replaced by an
* alternative which results in decoupling the lifetime of the struct
* device from the i2c_adapter, like spi or netdev do. Any solution
* should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
*/
init_completion(&adap->dev_released);
device_unregister(&adap->dev);
wait_for_completion(&adap->dev_released);
/* free bus id */
mutex_lock(&core_lock);
idr_remove(&i2c_adapter_idr, adap->nr);
mutex_unlock(&core_lock);
/* Clear the device structure in case this adapter is ever going to be
added again */
memset(&adap->dev, 0, sizeof(adap->dev));
}
EXPORT_SYMBOL(i2c_del_adapter);
/**
* i2c_parse_fw_timings - get I2C related timing parameters from firmware
* @dev: The device to scan for I2C timing properties
* @t: the i2c_timings struct to be filled with values
* @use_defaults: bool to use sane defaults derived from the I2C specification
* when properties are not found, otherwise use 0
*
* Scan the device for the generic I2C properties describing timing parameters
* for the signal and fill the given struct with the results. If a property was
* not found and use_defaults was true, then maximum timings are assumed which
* are derived from the I2C specification. If use_defaults is not used, the
* results will be 0, so drivers can apply their own defaults later. The latter
* is mainly intended for avoiding regressions of existing drivers which want
* to switch to this function. New drivers almost always should use the defaults.
*/
void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
{
int ret;
memset(t, 0, sizeof(*t));
ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
if (ret && use_defaults)
t->bus_freq_hz = 100000;
ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
if (ret && use_defaults) {
if (t->bus_freq_hz <= 100000)
t->scl_rise_ns = 1000;
else if (t->bus_freq_hz <= 400000)
t->scl_rise_ns = 300;
else
t->scl_rise_ns = 120;
}
ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
if (ret && use_defaults) {
if (t->bus_freq_hz <= 400000)
t->scl_fall_ns = 300;
else
t->scl_fall_ns = 120;
}
device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
if (ret && use_defaults)
t->sda_fall_ns = t->scl_fall_ns;
}
EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
/* ------------------------------------------------------------------------- */
int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
{
int res;
mutex_lock(&core_lock);
res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
mutex_unlock(&core_lock);
return res;
}
EXPORT_SYMBOL_GPL(i2c_for_each_dev);
static int __process_new_driver(struct device *dev, void *data)
{
if (dev->type != &i2c_adapter_type)
return 0;
return i2c_do_add_adapter(data, to_i2c_adapter(dev));
}
/*
* An i2c_driver is used with one or more i2c_client (device) nodes to access
* i2c slave chips, on a bus instance associated with some i2c_adapter.
*/
int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
{
int res;
/* Can't register until after driver model init */
if (WARN_ON(!is_registered))
return -EAGAIN;
/* add the driver to the list of i2c drivers in the driver core */
driver->driver.owner = owner;
driver->driver.bus = &i2c_bus_type;
INIT_LIST_HEAD(&driver->clients);
/* When registration returns, the driver core
* will have called probe() for all matching-but-unbound devices.
*/
res = driver_register(&driver->driver);
if (res)
return res;
pr_debug("driver [%s] registered\n", driver->driver.name);
/* Walk the adapters that are already present */
i2c_for_each_dev(driver, __process_new_driver);
return 0;
}
EXPORT_SYMBOL(i2c_register_driver);
static int __process_removed_driver(struct device *dev, void *data)
{
if (dev->type == &i2c_adapter_type)
i2c_do_del_adapter(data, to_i2c_adapter(dev));
return 0;
}
/**
* i2c_del_driver - unregister I2C driver
* @driver: the driver being unregistered
* Context: can sleep
*/
void i2c_del_driver(struct i2c_driver *driver)
{
i2c_for_each_dev(driver, __process_removed_driver);
driver_unregister(&driver->driver);
pr_debug("driver [%s] unregistered\n", driver->driver.name);
}
EXPORT_SYMBOL(i2c_del_driver);
/* ------------------------------------------------------------------------- */
/**
* i2c_use_client - increments the reference count of the i2c client structure
* @client: the client being referenced
*
* Each live reference to a client should be refcounted. The driver model does
* that automatically as part of driver binding, so that most drivers don't
* need to do this explicitly: they hold a reference until they're unbound
* from the device.
*
* A pointer to the client with the incremented reference counter is returned.
*/
struct i2c_client *i2c_use_client(struct i2c_client *client)
{
if (client && get_device(&client->dev))
return client;
return NULL;
}
EXPORT_SYMBOL(i2c_use_client);
/**
* i2c_release_client - release a use of the i2c client structure
* @client: the client being no longer referenced
*
* Must be called when a user of a client is finished with it.
*/
void i2c_release_client(struct i2c_client *client)
{
if (client)
put_device(&client->dev);
}
EXPORT_SYMBOL(i2c_release_client);
struct i2c_cmd_arg {
unsigned cmd;
void *arg;
};
static int i2c_cmd(struct device *dev, void *_arg)
{
struct i2c_client *client = i2c_verify_client(dev);
struct i2c_cmd_arg *arg = _arg;
struct i2c_driver *driver;
if (!client || !client->dev.driver)
return 0;
driver = to_i2c_driver(client->dev.driver);
if (driver->command)
driver->command(client, arg->cmd, arg->arg);
return 0;
}
void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
{
struct i2c_cmd_arg cmd_arg;
cmd_arg.cmd = cmd;
cmd_arg.arg = arg;
device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
}
EXPORT_SYMBOL(i2c_clients_command);
static int __init i2c_init(void)
{
int retval;
retval = of_alias_get_highest_id("i2c");
down_write(&__i2c_board_lock);
if (retval >= __i2c_first_dynamic_bus_num)
__i2c_first_dynamic_bus_num = retval + 1;
up_write(&__i2c_board_lock);
retval = bus_register(&i2c_bus_type);
if (retval)
return retval;
is_registered = true;
#ifdef CONFIG_I2C_COMPAT
i2c_adapter_compat_class = class_compat_register("i2c-adapter");
if (!i2c_adapter_compat_class) {
retval = -ENOMEM;
goto bus_err;
}
#endif
retval = i2c_add_driver(&dummy_driver);
if (retval)
goto class_err;
if (IS_ENABLED(CONFIG_OF_DYNAMIC))
WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
if (IS_ENABLED(CONFIG_ACPI))
WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
return 0;
class_err:
#ifdef CONFIG_I2C_COMPAT
class_compat_unregister(i2c_adapter_compat_class);
bus_err:
#endif
is_registered = false;
bus_unregister(&i2c_bus_type);
return retval;
}
static void __exit i2c_exit(void)
{
if (IS_ENABLED(CONFIG_ACPI))
WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
if (IS_ENABLED(CONFIG_OF_DYNAMIC))
WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
i2c_del_driver(&dummy_driver);
#ifdef CONFIG_I2C_COMPAT
class_compat_unregister(i2c_adapter_compat_class);
#endif
bus_unregister(&i2c_bus_type);
tracepoint_synchronize_unregister();
}
/* We must initialize early, because some subsystems register i2c drivers
* in subsys_initcall() code, but are linked (and initialized) before i2c.
*/
postcore_initcall(i2c_init);
module_exit(i2c_exit);
/* ----------------------------------------------------
* the functional interface to the i2c busses.
* ----------------------------------------------------
*/
/* Check if val is exceeding the quirk IFF quirk is non 0 */
#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
{
dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
err_msg, msg->addr, msg->len,
msg->flags & I2C_M_RD ? "read" : "write");
return -EOPNOTSUPP;
}
static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
const struct i2c_adapter_quirks *q = adap->quirks;
int max_num = q->max_num_msgs, i;
bool do_len_check = true;
if (q->flags & I2C_AQ_COMB) {
max_num = 2;
/* special checks for combined messages */
if (num == 2) {
if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
return i2c_quirk_error(adap, &msgs[0], "msg too long");
if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
return i2c_quirk_error(adap, &msgs[1], "msg too long");
do_len_check = false;
}
}
if (i2c_quirk_exceeded(num, max_num))
return i2c_quirk_error(adap, &msgs[0], "too many messages");
for (i = 0; i < num; i++) {
u16 len = msgs[i].len;
if (msgs[i].flags & I2C_M_RD) {
if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
return i2c_quirk_error(adap, &msgs[i], "msg too long");
} else {
if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
return i2c_quirk_error(adap, &msgs[i], "msg too long");
}
}
return 0;
}
/**
* __i2c_transfer - unlocked flavor of i2c_transfer
* @adap: Handle to I2C bus
* @msgs: One or more messages to execute before STOP is issued to
* terminate the operation; each message begins with a START.
* @num: Number of messages to be executed.
*
* Returns negative errno, else the number of messages executed.
*
* Adapter lock must be held when calling this function. No debug logging
* takes place. adap->algo->master_xfer existence isn't checked.
*/
int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
unsigned long orig_jiffies;
int ret, try;
if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
return -EOPNOTSUPP;
/* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
* enabled. This is an efficient way of keeping the for-loop from
* being executed when not needed.
*/
if (static_key_false(&i2c_trace_msg)) {
int i;
for (i = 0; i < num; i++)
if (msgs[i].flags & I2C_M_RD)
trace_i2c_read(adap, &msgs[i], i);
else
trace_i2c_write(adap, &msgs[i], i);
}
/* Retry automatically on arbitration loss */
orig_jiffies = jiffies;
for (ret = 0, try = 0; try <= adap->retries; try++) {
ret = adap->algo->master_xfer(adap, msgs, num);
if (ret != -EAGAIN)
break;
if (time_after(jiffies, orig_jiffies + adap->timeout))
break;
}
if (static_key_false(&i2c_trace_msg)) {
int i;
for (i = 0; i < ret; i++)
if (msgs[i].flags & I2C_M_RD)
trace_i2c_reply(adap, &msgs[i], i);
trace_i2c_result(adap, i, ret);
}
return ret;
}
EXPORT_SYMBOL(__i2c_transfer);
/**
* i2c_transfer - execute a single or combined I2C message
* @adap: Handle to I2C bus
* @msgs: One or more messages to execute before STOP is issued to
* terminate the operation; each message begins with a START.
* @num: Number of messages to be executed.
*
* Returns negative errno, else the number of messages executed.
*
* Note that there is no requirement that each message be sent to
* the same slave address, although that is the most common model.
*/
int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
int ret;
/* REVISIT the fault reporting model here is weak:
*
* - When we get an error after receiving N bytes from a slave,
* there is no way to report "N".
*
* - When we get a NAK after transmitting N bytes to a slave,
* there is no way to report "N" ... or to let the master
* continue executing the rest of this combined message, if
* that's the appropriate response.
*
* - When for example "num" is two and we successfully complete
* the first message but get an error part way through the
* second, it's unclear whether that should be reported as
* one (discarding status on the second message) or errno
* (discarding status on the first one).
*/
if (adap->algo->master_xfer) {
#ifdef DEBUG
for (ret = 0; ret < num; ret++) {
dev_dbg(&adap->dev,
"master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W',
msgs[ret].addr, msgs[ret].len,
(msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
}
#endif
if (in_atomic() || irqs_disabled()) {
ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
if (!ret)
/* I2C activity is ongoing. */
return -EAGAIN;
} else {
i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
}
ret = __i2c_transfer(adap, msgs, num);
i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
return ret;
} else {
dev_dbg(&adap->dev, "I2C level transfers not supported\n");
return -EOPNOTSUPP;
}
}
EXPORT_SYMBOL(i2c_transfer);
/**
* i2c_master_send - issue a single I2C message in master transmit mode
* @client: Handle to slave device
* @buf: Data that will be written to the slave
* @count: How many bytes to write, must be less than 64k since msg.len is u16
*
* Returns negative errno, or else the number of bytes written.
*/
int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
{
int ret;
struct i2c_adapter *adap = client->adapter;
struct i2c_msg msg;
msg.addr = client->addr;
msg.flags = client->flags & I2C_M_TEN;
msg.len = count;
msg.buf = (char *)buf;
ret = i2c_transfer(adap, &msg, 1);
/*
* If everything went ok (i.e. 1 msg transmitted), return #bytes
* transmitted, else error code.
*/
return (ret == 1) ? count : ret;
}
EXPORT_SYMBOL(i2c_master_send);
/**
* i2c_master_recv - issue a single I2C message in master receive mode
* @client: Handle to slave device
* @buf: Where to store data read from slave
* @count: How many bytes to read, must be less than 64k since msg.len is u16
*
* Returns negative errno, or else the number of bytes read.
*/
int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
{
struct i2c_adapter *adap = client->adapter;
struct i2c_msg msg;
int ret;
msg.addr = client->addr;
msg.flags = client->flags & I2C_M_TEN;
msg.flags |= I2C_M_RD;
msg.len = count;
msg.buf = buf;
ret = i2c_transfer(adap, &msg, 1);
/*
* If everything went ok (i.e. 1 msg received), return #bytes received,
* else error code.
*/
return (ret == 1) ? count : ret;
}
EXPORT_SYMBOL(i2c_master_recv);
/* ----------------------------------------------------
* the i2c address scanning function
* Will not work for 10-bit addresses!
* ----------------------------------------------------
*/
/*
* Legacy default probe function, mostly relevant for SMBus. The default
* probe method is a quick write, but it is known to corrupt the 24RF08
* EEPROMs due to a state machine bug, and could also irreversibly
* write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
* we use a short byte read instead. Also, some bus drivers don't implement
* quick write, so we fallback to a byte read in that case too.
* On x86, there is another special case for FSC hardware monitoring chips,
* which want regular byte reads (address 0x73.) Fortunately, these are the
* only known chips using this I2C address on PC hardware.
* Returns 1 if probe succeeded, 0 if not.
*/
static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
{
int err;
union i2c_smbus_data dummy;
#ifdef CONFIG_X86
if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
&& i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
I2C_SMBUS_BYTE_DATA, &dummy);
else
#endif
if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
&& i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
I2C_SMBUS_QUICK, NULL);
else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
I2C_SMBUS_BYTE, &dummy);
else {
dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
addr);
err = -EOPNOTSUPP;
}
return err >= 0;
}
static int i2c_detect_address(struct i2c_client *temp_client,
struct i2c_driver *driver)
{
struct i2c_board_info info;
struct i2c_adapter *adapter = temp_client->adapter;
int addr = temp_client->addr;
int err;
/* Make sure the address is valid */
err = i2c_check_7bit_addr_validity_strict(addr);
if (err) {
dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
addr);
return err;
}
/* Skip if already in use (7 bit, no need to encode flags) */
if (i2c_check_addr_busy(adapter, addr))
return 0;
/* Make sure there is something at this address */
if (!i2c_default_probe(adapter, addr))
return 0;
/* Finally call the custom detection function */
memset(&info, 0, sizeof(struct i2c_board_info));
info.addr = addr;
err = driver->detect(temp_client, &info);
if (err) {
/* -ENODEV is returned if the detection fails. We catch it
here as this isn't an error. */
return err == -ENODEV ? 0 : err;
}
/* Consistency check */
if (info.type[0] == '\0') {
dev_err(&adapter->dev,
"%s detection function provided no name for 0x%x\n",
driver->driver.name, addr);
} else {
struct i2c_client *client;
/* Detection succeeded, instantiate the device */
if (adapter->class & I2C_CLASS_DEPRECATED)
dev_warn(&adapter->dev,
"This adapter will soon drop class based instantiation of devices. "
"Please make sure client 0x%02x gets instantiated by other means. "
"Check 'Documentation/i2c/instantiating-devices' for details.\n",
info.addr);
dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
info.type, info.addr);
client = i2c_new_device(adapter, &info);
if (client)
list_add_tail(&client->detected, &driver->clients);
else
dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
info.type, info.addr);
}
return 0;
}
static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
{
const unsigned short *address_list;
struct i2c_client *temp_client;
int i, err = 0;
int adap_id = i2c_adapter_id(adapter);
address_list = driver->address_list;
if (!driver->detect || !address_list)
return 0;
/* Warn that the adapter lost class based instantiation */
if (adapter->class == I2C_CLASS_DEPRECATED) {
dev_dbg(&adapter->dev,
"This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
"If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
driver->driver.name);
return 0;
}
/* Stop here if the classes do not match */
if (!(adapter->class & driver->class))
return 0;
/* Set up a temporary client to help detect callback */
temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
if (!temp_client)
return -ENOMEM;
temp_client->adapter = adapter;
for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
dev_dbg(&adapter->dev,
"found normal entry for adapter %d, addr 0x%02x\n",
adap_id, address_list[i]);
temp_client->addr = address_list[i];
err = i2c_detect_address(temp_client, driver);
if (unlikely(err))
break;
}
kfree(temp_client);
return err;
}
int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
{
return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
I2C_SMBUS_QUICK, NULL) >= 0;
}
EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
struct i2c_client *
i2c_new_probed_device(struct i2c_adapter *adap,
struct i2c_board_info *info,
unsigned short const *addr_list,
int (*probe)(struct i2c_adapter *, unsigned short addr))
{
int i;
if (!probe)
probe = i2c_default_probe;
for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
/* Check address validity */
if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
addr_list[i]);
continue;
}
/* Check address availability (7 bit, no need to encode flags) */
if (i2c_check_addr_busy(adap, addr_list[i])) {
dev_dbg(&adap->dev,
"Address 0x%02x already in use, not probing\n",
addr_list[i]);
continue;
}
/* Test address responsiveness */
if (probe(adap, addr_list[i]))
break;
}
if (addr_list[i] == I2C_CLIENT_END) {
dev_dbg(&adap->dev, "Probing failed, no device found\n");
return NULL;
}
info->addr = addr_list[i];
return i2c_new_device(adap, info);
}
EXPORT_SYMBOL_GPL(i2c_new_probed_device);
struct i2c_adapter *i2c_get_adapter(int nr)
{
struct i2c_adapter *adapter;
mutex_lock(&core_lock);
adapter = idr_find(&i2c_adapter_idr, nr);
if (!adapter)
goto exit;
if (try_module_get(adapter->owner))
get_device(&adapter->dev);
else
adapter = NULL;
exit:
mutex_unlock(&core_lock);
return adapter;
}
EXPORT_SYMBOL(i2c_get_adapter);
void i2c_put_adapter(struct i2c_adapter *adap)
{
if (!adap)
return;
put_device(&adap->dev);
module_put(adap->owner);
}
EXPORT_SYMBOL(i2c_put_adapter);
MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
MODULE_DESCRIPTION("I2C-Bus main module");
MODULE_LICENSE("GPL");