linux/drivers/i2c/i2c-core-acpi.c
Russell King (Oracle) 373c612d72 i2c: add fwnode APIs
Add fwnode APIs for finding and getting I2C adapters, which will be
used by the SFP code. These are passed the fwnode corresponding to
the adapter, and return the I2C adapter. It is the responsibility of
the caller to find the appropriate fwnode.

We keep the DT and ACPI interfaces, but where appropriate, recode them
to use the fwnode interfaces internally.

Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
2023-01-17 09:29:59 +01:00

814 lines
20 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Linux I2C core ACPI support code
*
* Copyright (C) 2014 Intel Corp, Author: Lan Tianyu <tianyu.lan@intel.com>
*/
#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/slab.h>
#include "i2c-core.h"
struct i2c_acpi_handler_data {
struct acpi_connection_info info;
struct i2c_adapter *adapter;
};
struct gsb_buffer {
u8 status;
u8 len;
union {
u16 wdata;
u8 bdata;
DECLARE_FLEX_ARRAY(u8, data);
};
} __packed;
struct i2c_acpi_lookup {
struct i2c_board_info *info;
acpi_handle adapter_handle;
acpi_handle device_handle;
acpi_handle search_handle;
int n;
int index;
u32 speed;
u32 min_speed;
u32 force_speed;
};
/**
* i2c_acpi_get_i2c_resource - Gets I2cSerialBus resource if type matches
* @ares: ACPI resource
* @i2c: Pointer to I2cSerialBus resource will be returned here
*
* Checks if the given ACPI resource is of type I2cSerialBus.
* In this case, returns a pointer to it to the caller.
*
* Returns true if resource type is of I2cSerialBus, otherwise false.
*/
bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
struct acpi_resource_i2c_serialbus **i2c)
{
struct acpi_resource_i2c_serialbus *sb;
if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
return false;
sb = &ares->data.i2c_serial_bus;
if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
return false;
*i2c = sb;
return true;
}
EXPORT_SYMBOL_GPL(i2c_acpi_get_i2c_resource);
static int i2c_acpi_resource_count(struct acpi_resource *ares, void *data)
{
struct acpi_resource_i2c_serialbus *sb;
int *count = data;
if (i2c_acpi_get_i2c_resource(ares, &sb))
*count = *count + 1;
return 1;
}
/**
* i2c_acpi_client_count - Count the number of I2cSerialBus resources
* @adev: ACPI device
*
* Returns the number of I2cSerialBus resources in the ACPI-device's
* resource-list; or a negative error code.
*/
int i2c_acpi_client_count(struct acpi_device *adev)
{
int ret, count = 0;
LIST_HEAD(r);
ret = acpi_dev_get_resources(adev, &r, i2c_acpi_resource_count, &count);
if (ret < 0)
return ret;
acpi_dev_free_resource_list(&r);
return count;
}
EXPORT_SYMBOL_GPL(i2c_acpi_client_count);
static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
{
struct i2c_acpi_lookup *lookup = data;
struct i2c_board_info *info = lookup->info;
struct acpi_resource_i2c_serialbus *sb;
acpi_status status;
if (info->addr || !i2c_acpi_get_i2c_resource(ares, &sb))
return 1;
if (lookup->index != -1 && lookup->n++ != lookup->index)
return 1;
status = acpi_get_handle(lookup->device_handle,
sb->resource_source.string_ptr,
&lookup->adapter_handle);
if (ACPI_FAILURE(status))
return 1;
info->addr = sb->slave_address;
lookup->speed = sb->connection_speed;
if (sb->access_mode == ACPI_I2C_10BIT_MODE)
info->flags |= I2C_CLIENT_TEN;
return 1;
}
static const struct acpi_device_id i2c_acpi_ignored_device_ids[] = {
/*
* ACPI video acpi_devices, which are handled by the acpi-video driver
* sometimes contain a SERIAL_TYPE_I2C ACPI resource, ignore these.
*/
{ ACPI_VIDEO_HID, 0 },
{}
};
struct i2c_acpi_irq_context {
int irq;
bool wake_capable;
};
static int i2c_acpi_do_lookup(struct acpi_device *adev,
struct i2c_acpi_lookup *lookup)
{
struct i2c_board_info *info = lookup->info;
struct list_head resource_list;
int ret;
if (acpi_bus_get_status(adev))
return -EINVAL;
if (!acpi_dev_ready_for_enumeration(adev))
return -ENODEV;
if (acpi_match_device_ids(adev, i2c_acpi_ignored_device_ids) == 0)
return -ENODEV;
memset(info, 0, sizeof(*info));
lookup->device_handle = acpi_device_handle(adev);
/* Look up for I2cSerialBus resource */
INIT_LIST_HEAD(&resource_list);
ret = acpi_dev_get_resources(adev, &resource_list,
i2c_acpi_fill_info, lookup);
acpi_dev_free_resource_list(&resource_list);
if (ret < 0 || !info->addr)
return -EINVAL;
return 0;
}
static int i2c_acpi_add_irq_resource(struct acpi_resource *ares, void *data)
{
struct i2c_acpi_irq_context *irq_ctx = data;
struct resource r;
if (irq_ctx->irq > 0)
return 1;
if (!acpi_dev_resource_interrupt(ares, 0, &r))
return 1;
irq_ctx->irq = i2c_dev_irq_from_resources(&r, 1);
irq_ctx->wake_capable = r.flags & IORESOURCE_IRQ_WAKECAPABLE;
return 1; /* No need to add resource to the list */
}
/**
* i2c_acpi_get_irq - get device IRQ number from ACPI
* @client: Pointer to the I2C client device
* @wake_capable: Set to true if the IRQ is wake capable
*
* Find the IRQ number used by a specific client device.
*
* Return: The IRQ number or an error code.
*/
int i2c_acpi_get_irq(struct i2c_client *client, bool *wake_capable)
{
struct acpi_device *adev = ACPI_COMPANION(&client->dev);
struct list_head resource_list;
struct i2c_acpi_irq_context irq_ctx = {
.irq = -ENOENT,
};
int ret;
INIT_LIST_HEAD(&resource_list);
ret = acpi_dev_get_resources(adev, &resource_list,
i2c_acpi_add_irq_resource, &irq_ctx);
if (ret < 0)
return ret;
acpi_dev_free_resource_list(&resource_list);
if (irq_ctx.irq == -ENOENT)
irq_ctx.irq = acpi_dev_gpio_irq_wake_get(adev, 0, &irq_ctx.wake_capable);
if (irq_ctx.irq < 0)
return irq_ctx.irq;
if (wake_capable)
*wake_capable = irq_ctx.wake_capable;
return irq_ctx.irq;
}
static int i2c_acpi_get_info(struct acpi_device *adev,
struct i2c_board_info *info,
struct i2c_adapter *adapter,
acpi_handle *adapter_handle)
{
struct i2c_acpi_lookup lookup;
int ret;
memset(&lookup, 0, sizeof(lookup));
lookup.info = info;
lookup.index = -1;
if (acpi_device_enumerated(adev))
return -EINVAL;
ret = i2c_acpi_do_lookup(adev, &lookup);
if (ret)
return ret;
if (adapter) {
/* The adapter must match the one in I2cSerialBus() connector */
if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle)
return -ENODEV;
} else {
struct acpi_device *adapter_adev;
/* The adapter must be present */
adapter_adev = acpi_fetch_acpi_dev(lookup.adapter_handle);
if (!adapter_adev)
return -ENODEV;
if (acpi_bus_get_status(adapter_adev) ||
!adapter_adev->status.present)
return -ENODEV;
}
info->fwnode = acpi_fwnode_handle(adev);
if (adapter_handle)
*adapter_handle = lookup.adapter_handle;
acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
sizeof(info->type));
return 0;
}
static void i2c_acpi_register_device(struct i2c_adapter *adapter,
struct acpi_device *adev,
struct i2c_board_info *info)
{
/*
* Skip registration on boards where the ACPI tables are
* known to contain bogus I2C devices.
*/
if (acpi_quirk_skip_i2c_client_enumeration(adev))
return;
adev->power.flags.ignore_parent = true;
acpi_device_set_enumerated(adev);
if (IS_ERR(i2c_new_client_device(adapter, info)))
adev->power.flags.ignore_parent = false;
}
static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level,
void *data, void **return_value)
{
struct i2c_adapter *adapter = data;
struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
struct i2c_board_info info;
if (!adev || i2c_acpi_get_info(adev, &info, adapter, NULL))
return AE_OK;
i2c_acpi_register_device(adapter, adev, &info);
return AE_OK;
}
#define I2C_ACPI_MAX_SCAN_DEPTH 32
/**
* i2c_acpi_register_devices - enumerate I2C slave devices behind adapter
* @adap: pointer to adapter
*
* Enumerate all I2C slave devices behind this adapter by walking the ACPI
* namespace. When a device is found it will be added to the Linux device
* model and bound to the corresponding ACPI handle.
*/
void i2c_acpi_register_devices(struct i2c_adapter *adap)
{
struct acpi_device *adev;
acpi_status status;
if (!has_acpi_companion(&adap->dev))
return;
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
I2C_ACPI_MAX_SCAN_DEPTH,
i2c_acpi_add_device, NULL,
adap, NULL);
if (ACPI_FAILURE(status))
dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
if (!adap->dev.parent)
return;
adev = ACPI_COMPANION(adap->dev.parent);
if (!adev)
return;
acpi_dev_clear_dependencies(adev);
}
static const struct acpi_device_id i2c_acpi_force_400khz_device_ids[] = {
/*
* These Silead touchscreen controllers only work at 400KHz, for
* some reason they do not work at 100KHz. On some devices the ACPI
* tables list another device at their bus as only being capable
* of 100KHz, testing has shown that these other devices work fine
* at 400KHz (as can be expected of any recent i2c hw) so we force
* the speed of the bus to 400 KHz if a Silead device is present.
*/
{ "MSSL1680", 0 },
{}
};
static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
void *data, void **return_value)
{
struct i2c_acpi_lookup *lookup = data;
struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
if (!adev || i2c_acpi_do_lookup(adev, lookup))
return AE_OK;
if (lookup->search_handle != lookup->adapter_handle)
return AE_OK;
if (lookup->speed <= lookup->min_speed)
lookup->min_speed = lookup->speed;
if (acpi_match_device_ids(adev, i2c_acpi_force_400khz_device_ids) == 0)
lookup->force_speed = I2C_MAX_FAST_MODE_FREQ;
return AE_OK;
}
/**
* i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
* @dev: The device owning the bus
*
* Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
* devices connected to this bus and use the speed of slowest device.
*
* Returns the speed in Hz or zero
*/
u32 i2c_acpi_find_bus_speed(struct device *dev)
{
struct i2c_acpi_lookup lookup;
struct i2c_board_info dummy;
acpi_status status;
if (!has_acpi_companion(dev))
return 0;
memset(&lookup, 0, sizeof(lookup));
lookup.search_handle = ACPI_HANDLE(dev);
lookup.min_speed = UINT_MAX;
lookup.info = &dummy;
lookup.index = -1;
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
I2C_ACPI_MAX_SCAN_DEPTH,
i2c_acpi_lookup_speed, NULL,
&lookup, NULL);
if (ACPI_FAILURE(status)) {
dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
return 0;
}
if (lookup.force_speed) {
if (lookup.force_speed != lookup.min_speed)
dev_warn(dev, FW_BUG "DSDT uses known not-working I2C bus speed %d, forcing it to %d\n",
lookup.min_speed, lookup.force_speed);
return lookup.force_speed;
} else if (lookup.min_speed != UINT_MAX) {
return lookup.min_speed;
} else {
return 0;
}
}
EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
{
struct i2c_adapter *adapter;
struct device *dev;
dev = bus_find_device(&i2c_bus_type, NULL, handle, device_match_acpi_handle);
if (!dev)
return NULL;
adapter = i2c_verify_adapter(dev);
if (!adapter)
put_device(dev);
return adapter;
}
EXPORT_SYMBOL_GPL(i2c_acpi_find_adapter_by_handle);
static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
{
return i2c_find_device_by_fwnode(acpi_fwnode_handle(adev));
}
static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
void *arg)
{
struct acpi_device *adev = arg;
struct i2c_board_info info;
acpi_handle adapter_handle;
struct i2c_adapter *adapter;
struct i2c_client *client;
switch (value) {
case ACPI_RECONFIG_DEVICE_ADD:
if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
break;
adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
if (!adapter)
break;
i2c_acpi_register_device(adapter, adev, &info);
put_device(&adapter->dev);
break;
case ACPI_RECONFIG_DEVICE_REMOVE:
if (!acpi_device_enumerated(adev))
break;
client = i2c_acpi_find_client_by_adev(adev);
if (!client)
break;
i2c_unregister_device(client);
put_device(&client->dev);
break;
}
return NOTIFY_OK;
}
struct notifier_block i2c_acpi_notifier = {
.notifier_call = i2c_acpi_notify,
};
/**
* i2c_acpi_new_device_by_fwnode - Create i2c-client for the Nth I2cSerialBus resource
* @fwnode: fwnode with the ACPI resources to get the client from
* @index: Index of ACPI resource to get
* @info: describes the I2C device; note this is modified (addr gets set)
* Context: can sleep
*
* By default the i2c subsys creates an i2c-client for the first I2cSerialBus
* resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
* resources, in that case this function can be used to create an i2c-client
* for other I2cSerialBus resources in the Current Resource Settings table.
*
* Also see i2c_new_client_device, which this function calls to create the
* i2c-client.
*
* Returns a pointer to the new i2c-client, or error pointer in case of failure.
* Specifically, -EPROBE_DEFER is returned if the adapter is not found.
*/
struct i2c_client *i2c_acpi_new_device_by_fwnode(struct fwnode_handle *fwnode,
int index,
struct i2c_board_info *info)
{
struct i2c_acpi_lookup lookup;
struct i2c_adapter *adapter;
struct acpi_device *adev;
LIST_HEAD(resource_list);
int ret;
adev = to_acpi_device_node(fwnode);
if (!adev)
return ERR_PTR(-ENODEV);
memset(&lookup, 0, sizeof(lookup));
lookup.info = info;
lookup.device_handle = acpi_device_handle(adev);
lookup.index = index;
ret = acpi_dev_get_resources(adev, &resource_list,
i2c_acpi_fill_info, &lookup);
if (ret < 0)
return ERR_PTR(ret);
acpi_dev_free_resource_list(&resource_list);
if (!info->addr)
return ERR_PTR(-EADDRNOTAVAIL);
adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
if (!adapter)
return ERR_PTR(-EPROBE_DEFER);
return i2c_new_client_device(adapter, info);
}
EXPORT_SYMBOL_GPL(i2c_acpi_new_device_by_fwnode);
bool i2c_acpi_waive_d0_probe(struct device *dev)
{
struct i2c_driver *driver = to_i2c_driver(dev->driver);
struct acpi_device *adev = ACPI_COMPANION(dev);
return driver->flags & I2C_DRV_ACPI_WAIVE_D0_PROBE &&
adev && adev->power.state_for_enumeration >= adev->power.state;
}
EXPORT_SYMBOL_GPL(i2c_acpi_waive_d0_probe);
#ifdef CONFIG_ACPI_I2C_OPREGION
static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
u8 cmd, u8 *data, u8 data_len)
{
struct i2c_msg msgs[2];
int ret;
u8 *buffer;
buffer = kzalloc(data_len, GFP_KERNEL);
if (!buffer)
return AE_NO_MEMORY;
msgs[0].addr = client->addr;
msgs[0].flags = client->flags;
msgs[0].len = 1;
msgs[0].buf = &cmd;
msgs[1].addr = client->addr;
msgs[1].flags = client->flags | I2C_M_RD;
msgs[1].len = data_len;
msgs[1].buf = buffer;
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
if (ret < 0) {
/* Getting a NACK is unfortunately normal with some DSTDs */
if (ret == -EREMOTEIO)
dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
data_len, client->addr, cmd, ret);
else
dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
data_len, client->addr, cmd, ret);
/* 2 transfers must have completed successfully */
} else if (ret == 2) {
memcpy(data, buffer, data_len);
ret = 0;
} else {
ret = -EIO;
}
kfree(buffer);
return ret;
}
static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
u8 cmd, u8 *data, u8 data_len)
{
struct i2c_msg msgs[1];
u8 *buffer;
int ret = AE_OK;
buffer = kzalloc(data_len + 1, GFP_KERNEL);
if (!buffer)
return AE_NO_MEMORY;
buffer[0] = cmd;
memcpy(buffer + 1, data, data_len);
msgs[0].addr = client->addr;
msgs[0].flags = client->flags;
msgs[0].len = data_len + 1;
msgs[0].buf = buffer;
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
kfree(buffer);
if (ret < 0) {
dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret);
return ret;
}
/* 1 transfer must have completed successfully */
return (ret == 1) ? 0 : -EIO;
}
static acpi_status
i2c_acpi_space_handler(u32 function, acpi_physical_address command,
u32 bits, u64 *value64,
void *handler_context, void *region_context)
{
struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
struct i2c_acpi_handler_data *data = handler_context;
struct acpi_connection_info *info = &data->info;
struct acpi_resource_i2c_serialbus *sb;
struct i2c_adapter *adapter = data->adapter;
struct i2c_client *client;
struct acpi_resource *ares;
u32 accessor_type = function >> 16;
u8 action = function & ACPI_IO_MASK;
acpi_status ret;
int status;
ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
if (ACPI_FAILURE(ret))
return ret;
client = kzalloc(sizeof(*client), GFP_KERNEL);
if (!client) {
ret = AE_NO_MEMORY;
goto err;
}
if (!value64 || !i2c_acpi_get_i2c_resource(ares, &sb)) {
ret = AE_BAD_PARAMETER;
goto err;
}
client->adapter = adapter;
client->addr = sb->slave_address;
if (sb->access_mode == ACPI_I2C_10BIT_MODE)
client->flags |= I2C_CLIENT_TEN;
switch (accessor_type) {
case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
if (action == ACPI_READ) {
status = i2c_smbus_read_byte(client);
if (status >= 0) {
gsb->bdata = status;
status = 0;
}
} else {
status = i2c_smbus_write_byte(client, gsb->bdata);
}
break;
case ACPI_GSB_ACCESS_ATTRIB_BYTE:
if (action == ACPI_READ) {
status = i2c_smbus_read_byte_data(client, command);
if (status >= 0) {
gsb->bdata = status;
status = 0;
}
} else {
status = i2c_smbus_write_byte_data(client, command,
gsb->bdata);
}
break;
case ACPI_GSB_ACCESS_ATTRIB_WORD:
if (action == ACPI_READ) {
status = i2c_smbus_read_word_data(client, command);
if (status >= 0) {
gsb->wdata = status;
status = 0;
}
} else {
status = i2c_smbus_write_word_data(client, command,
gsb->wdata);
}
break;
case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
if (action == ACPI_READ) {
status = i2c_smbus_read_block_data(client, command,
gsb->data);
if (status >= 0) {
gsb->len = status;
status = 0;
}
} else {
status = i2c_smbus_write_block_data(client, command,
gsb->len, gsb->data);
}
break;
case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
if (action == ACPI_READ) {
status = acpi_gsb_i2c_read_bytes(client, command,
gsb->data, info->access_length);
} else {
status = acpi_gsb_i2c_write_bytes(client, command,
gsb->data, info->access_length);
}
break;
default:
dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
accessor_type, client->addr);
ret = AE_BAD_PARAMETER;
goto err;
}
gsb->status = status;
err:
kfree(client);
ACPI_FREE(ares);
return ret;
}
int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
{
acpi_handle handle;
struct i2c_acpi_handler_data *data;
acpi_status status;
if (!adapter->dev.parent)
return -ENODEV;
handle = ACPI_HANDLE(adapter->dev.parent);
if (!handle)
return -ENODEV;
data = kzalloc(sizeof(struct i2c_acpi_handler_data),
GFP_KERNEL);
if (!data)
return -ENOMEM;
data->adapter = adapter;
status = acpi_bus_attach_private_data(handle, (void *)data);
if (ACPI_FAILURE(status)) {
kfree(data);
return -ENOMEM;
}
status = acpi_install_address_space_handler(handle,
ACPI_ADR_SPACE_GSBUS,
&i2c_acpi_space_handler,
NULL,
data);
if (ACPI_FAILURE(status)) {
dev_err(&adapter->dev, "Error installing i2c space handler\n");
acpi_bus_detach_private_data(handle);
kfree(data);
return -ENOMEM;
}
return 0;
}
void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
{
acpi_handle handle;
struct i2c_acpi_handler_data *data;
acpi_status status;
if (!adapter->dev.parent)
return;
handle = ACPI_HANDLE(adapter->dev.parent);
if (!handle)
return;
acpi_remove_address_space_handler(handle,
ACPI_ADR_SPACE_GSBUS,
&i2c_acpi_space_handler);
status = acpi_bus_get_private_data(handle, (void **)&data);
if (ACPI_SUCCESS(status))
kfree(data);
acpi_bus_detach_private_data(handle);
}
#endif /* CONFIG_ACPI_I2C_OPREGION */