linux/drivers/misc/eeprom/eeprom_93xx46.c
Mark Brown dd69a18ae7 eeprom: 93xx46: Fix SPI device leak
The 93xx46 driver is using spi_dev_get() apparently just to take a copy
of the SPI device used to instantiate it but never calls spi_dev_put()
to free it.  Since the device is guaranteed to exist between probe() and
remove() there should be no need for the driver to take an extra
reference to it so fix the leak by just using a straight assignment.

Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-01 14:04:19 -07:00

536 lines
11 KiB
C

/*
* Driver for 93xx46 EEPROMs
*
* (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/gpio/consumer.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/nvmem-provider.h>
#include <linux/eeprom_93xx46.h>
#define OP_START 0x4
#define OP_WRITE (OP_START | 0x1)
#define OP_READ (OP_START | 0x2)
#define ADDR_EWDS 0x00
#define ADDR_ERAL 0x20
#define ADDR_EWEN 0x30
struct eeprom_93xx46_devtype_data {
unsigned int quirks;
};
static const struct eeprom_93xx46_devtype_data atmel_at93c46d_data = {
.quirks = EEPROM_93XX46_QUIRK_SINGLE_WORD_READ |
EEPROM_93XX46_QUIRK_INSTRUCTION_LENGTH,
};
struct eeprom_93xx46_dev {
struct spi_device *spi;
struct eeprom_93xx46_platform_data *pdata;
struct mutex lock;
struct nvmem_config nvmem_config;
struct nvmem_device *nvmem;
int addrlen;
int size;
};
static inline bool has_quirk_single_word_read(struct eeprom_93xx46_dev *edev)
{
return edev->pdata->quirks & EEPROM_93XX46_QUIRK_SINGLE_WORD_READ;
}
static inline bool has_quirk_instruction_length(struct eeprom_93xx46_dev *edev)
{
return edev->pdata->quirks & EEPROM_93XX46_QUIRK_INSTRUCTION_LENGTH;
}
static int eeprom_93xx46_read(void *priv, unsigned int off,
void *val, size_t count)
{
struct eeprom_93xx46_dev *edev = priv;
char *buf = val;
int err = 0;
if (unlikely(off >= edev->size))
return 0;
if ((off + count) > edev->size)
count = edev->size - off;
if (unlikely(!count))
return count;
mutex_lock(&edev->lock);
if (edev->pdata->prepare)
edev->pdata->prepare(edev);
while (count) {
struct spi_message m;
struct spi_transfer t[2] = { { 0 } };
u16 cmd_addr = OP_READ << edev->addrlen;
size_t nbytes = count;
int bits;
if (edev->addrlen == 7) {
cmd_addr |= off & 0x7f;
bits = 10;
if (has_quirk_single_word_read(edev))
nbytes = 1;
} else {
cmd_addr |= (off >> 1) & 0x3f;
bits = 9;
if (has_quirk_single_word_read(edev))
nbytes = 2;
}
dev_dbg(&edev->spi->dev, "read cmd 0x%x, %d Hz\n",
cmd_addr, edev->spi->max_speed_hz);
spi_message_init(&m);
t[0].tx_buf = (char *)&cmd_addr;
t[0].len = 2;
t[0].bits_per_word = bits;
spi_message_add_tail(&t[0], &m);
t[1].rx_buf = buf;
t[1].len = count;
t[1].bits_per_word = 8;
spi_message_add_tail(&t[1], &m);
err = spi_sync(edev->spi, &m);
/* have to wait at least Tcsl ns */
ndelay(250);
if (err) {
dev_err(&edev->spi->dev, "read %zu bytes at %d: err. %d\n",
nbytes, (int)off, err);
break;
}
buf += nbytes;
off += nbytes;
count -= nbytes;
}
if (edev->pdata->finish)
edev->pdata->finish(edev);
mutex_unlock(&edev->lock);
return err;
}
static int eeprom_93xx46_ew(struct eeprom_93xx46_dev *edev, int is_on)
{
struct spi_message m;
struct spi_transfer t;
int bits, ret;
u16 cmd_addr;
cmd_addr = OP_START << edev->addrlen;
if (edev->addrlen == 7) {
cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS) << 1;
bits = 10;
} else {
cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS);
bits = 9;
}
if (has_quirk_instruction_length(edev)) {
cmd_addr <<= 2;
bits += 2;
}
dev_dbg(&edev->spi->dev, "ew%s cmd 0x%04x, %d bits\n",
is_on ? "en" : "ds", cmd_addr, bits);
spi_message_init(&m);
memset(&t, 0, sizeof(t));
t.tx_buf = &cmd_addr;
t.len = 2;
t.bits_per_word = bits;
spi_message_add_tail(&t, &m);
mutex_lock(&edev->lock);
if (edev->pdata->prepare)
edev->pdata->prepare(edev);
ret = spi_sync(edev->spi, &m);
/* have to wait at least Tcsl ns */
ndelay(250);
if (ret)
dev_err(&edev->spi->dev, "erase/write %sable error %d\n",
is_on ? "en" : "dis", ret);
if (edev->pdata->finish)
edev->pdata->finish(edev);
mutex_unlock(&edev->lock);
return ret;
}
static ssize_t
eeprom_93xx46_write_word(struct eeprom_93xx46_dev *edev,
const char *buf, unsigned off)
{
struct spi_message m;
struct spi_transfer t[2];
int bits, data_len, ret;
u16 cmd_addr;
cmd_addr = OP_WRITE << edev->addrlen;
if (edev->addrlen == 7) {
cmd_addr |= off & 0x7f;
bits = 10;
data_len = 1;
} else {
cmd_addr |= (off >> 1) & 0x3f;
bits = 9;
data_len = 2;
}
dev_dbg(&edev->spi->dev, "write cmd 0x%x\n", cmd_addr);
spi_message_init(&m);
memset(t, 0, sizeof(t));
t[0].tx_buf = (char *)&cmd_addr;
t[0].len = 2;
t[0].bits_per_word = bits;
spi_message_add_tail(&t[0], &m);
t[1].tx_buf = buf;
t[1].len = data_len;
t[1].bits_per_word = 8;
spi_message_add_tail(&t[1], &m);
ret = spi_sync(edev->spi, &m);
/* have to wait program cycle time Twc ms */
mdelay(6);
return ret;
}
static int eeprom_93xx46_write(void *priv, unsigned int off,
void *val, size_t count)
{
struct eeprom_93xx46_dev *edev = priv;
char *buf = val;
int i, ret, step = 1;
if (unlikely(off >= edev->size))
return -EFBIG;
if ((off + count) > edev->size)
count = edev->size - off;
if (unlikely(!count))
return count;
/* only write even number of bytes on 16-bit devices */
if (edev->addrlen == 6) {
step = 2;
count &= ~1;
}
/* erase/write enable */
ret = eeprom_93xx46_ew(edev, 1);
if (ret)
return ret;
mutex_lock(&edev->lock);
if (edev->pdata->prepare)
edev->pdata->prepare(edev);
for (i = 0; i < count; i += step) {
ret = eeprom_93xx46_write_word(edev, &buf[i], off + i);
if (ret) {
dev_err(&edev->spi->dev, "write failed at %d: %d\n",
(int)off + i, ret);
break;
}
}
if (edev->pdata->finish)
edev->pdata->finish(edev);
mutex_unlock(&edev->lock);
/* erase/write disable */
eeprom_93xx46_ew(edev, 0);
return ret;
}
static int eeprom_93xx46_eral(struct eeprom_93xx46_dev *edev)
{
struct eeprom_93xx46_platform_data *pd = edev->pdata;
struct spi_message m;
struct spi_transfer t;
int bits, ret;
u16 cmd_addr;
cmd_addr = OP_START << edev->addrlen;
if (edev->addrlen == 7) {
cmd_addr |= ADDR_ERAL << 1;
bits = 10;
} else {
cmd_addr |= ADDR_ERAL;
bits = 9;
}
if (has_quirk_instruction_length(edev)) {
cmd_addr <<= 2;
bits += 2;
}
dev_dbg(&edev->spi->dev, "eral cmd 0x%04x, %d bits\n", cmd_addr, bits);
spi_message_init(&m);
memset(&t, 0, sizeof(t));
t.tx_buf = &cmd_addr;
t.len = 2;
t.bits_per_word = bits;
spi_message_add_tail(&t, &m);
mutex_lock(&edev->lock);
if (edev->pdata->prepare)
edev->pdata->prepare(edev);
ret = spi_sync(edev->spi, &m);
if (ret)
dev_err(&edev->spi->dev, "erase error %d\n", ret);
/* have to wait erase cycle time Tec ms */
mdelay(6);
if (pd->finish)
pd->finish(edev);
mutex_unlock(&edev->lock);
return ret;
}
static ssize_t eeprom_93xx46_store_erase(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct eeprom_93xx46_dev *edev = dev_get_drvdata(dev);
int erase = 0, ret;
sscanf(buf, "%d", &erase);
if (erase) {
ret = eeprom_93xx46_ew(edev, 1);
if (ret)
return ret;
ret = eeprom_93xx46_eral(edev);
if (ret)
return ret;
ret = eeprom_93xx46_ew(edev, 0);
if (ret)
return ret;
}
return count;
}
static DEVICE_ATTR(erase, S_IWUSR, NULL, eeprom_93xx46_store_erase);
static void select_assert(void *context)
{
struct eeprom_93xx46_dev *edev = context;
gpiod_set_value_cansleep(edev->pdata->select, 1);
}
static void select_deassert(void *context)
{
struct eeprom_93xx46_dev *edev = context;
gpiod_set_value_cansleep(edev->pdata->select, 0);
}
static const struct of_device_id eeprom_93xx46_of_table[] = {
{ .compatible = "eeprom-93xx46", },
{ .compatible = "atmel,at93c46d", .data = &atmel_at93c46d_data, },
{}
};
MODULE_DEVICE_TABLE(of, eeprom_93xx46_of_table);
static int eeprom_93xx46_probe_dt(struct spi_device *spi)
{
const struct of_device_id *of_id =
of_match_device(eeprom_93xx46_of_table, &spi->dev);
struct device_node *np = spi->dev.of_node;
struct eeprom_93xx46_platform_data *pd;
u32 tmp;
int gpio;
enum of_gpio_flags of_flags;
int ret;
pd = devm_kzalloc(&spi->dev, sizeof(*pd), GFP_KERNEL);
if (!pd)
return -ENOMEM;
ret = of_property_read_u32(np, "data-size", &tmp);
if (ret < 0) {
dev_err(&spi->dev, "data-size property not found\n");
return ret;
}
if (tmp == 8) {
pd->flags |= EE_ADDR8;
} else if (tmp == 16) {
pd->flags |= EE_ADDR16;
} else {
dev_err(&spi->dev, "invalid data-size (%d)\n", tmp);
return -EINVAL;
}
if (of_property_read_bool(np, "read-only"))
pd->flags |= EE_READONLY;
gpio = of_get_named_gpio_flags(np, "select-gpios", 0, &of_flags);
if (gpio_is_valid(gpio)) {
unsigned long flags =
of_flags == OF_GPIO_ACTIVE_LOW ? GPIOF_ACTIVE_LOW : 0;
ret = devm_gpio_request_one(&spi->dev, gpio, flags,
"eeprom_93xx46_select");
if (ret)
return ret;
pd->select = gpio_to_desc(gpio);
pd->prepare = select_assert;
pd->finish = select_deassert;
gpiod_direction_output(pd->select, 0);
}
if (of_id->data) {
const struct eeprom_93xx46_devtype_data *data = of_id->data;
pd->quirks = data->quirks;
}
spi->dev.platform_data = pd;
return 0;
}
static int eeprom_93xx46_probe(struct spi_device *spi)
{
struct eeprom_93xx46_platform_data *pd;
struct eeprom_93xx46_dev *edev;
int err;
if (spi->dev.of_node) {
err = eeprom_93xx46_probe_dt(spi);
if (err < 0)
return err;
}
pd = spi->dev.platform_data;
if (!pd) {
dev_err(&spi->dev, "missing platform data\n");
return -ENODEV;
}
edev = kzalloc(sizeof(*edev), GFP_KERNEL);
if (!edev)
return -ENOMEM;
if (pd->flags & EE_ADDR8)
edev->addrlen = 7;
else if (pd->flags & EE_ADDR16)
edev->addrlen = 6;
else {
dev_err(&spi->dev, "unspecified address type\n");
err = -EINVAL;
goto fail;
}
mutex_init(&edev->lock);
edev->spi = spi;
edev->pdata = pd;
edev->size = 128;
edev->nvmem_config.name = dev_name(&spi->dev);
edev->nvmem_config.dev = &spi->dev;
edev->nvmem_config.read_only = pd->flags & EE_READONLY;
edev->nvmem_config.root_only = true;
edev->nvmem_config.owner = THIS_MODULE;
edev->nvmem_config.compat = true;
edev->nvmem_config.base_dev = &spi->dev;
edev->nvmem_config.reg_read = eeprom_93xx46_read;
edev->nvmem_config.reg_write = eeprom_93xx46_write;
edev->nvmem_config.priv = edev;
edev->nvmem_config.stride = 4;
edev->nvmem_config.word_size = 1;
edev->nvmem_config.size = edev->size;
edev->nvmem = nvmem_register(&edev->nvmem_config);
if (IS_ERR(edev->nvmem)) {
err = PTR_ERR(edev->nvmem);
goto fail;
}
dev_info(&spi->dev, "%d-bit eeprom %s\n",
(pd->flags & EE_ADDR8) ? 8 : 16,
(pd->flags & EE_READONLY) ? "(readonly)" : "");
if (!(pd->flags & EE_READONLY)) {
if (device_create_file(&spi->dev, &dev_attr_erase))
dev_err(&spi->dev, "can't create erase interface\n");
}
spi_set_drvdata(spi, edev);
return 0;
fail:
kfree(edev);
return err;
}
static int eeprom_93xx46_remove(struct spi_device *spi)
{
struct eeprom_93xx46_dev *edev = spi_get_drvdata(spi);
nvmem_unregister(edev->nvmem);
if (!(edev->pdata->flags & EE_READONLY))
device_remove_file(&spi->dev, &dev_attr_erase);
kfree(edev);
return 0;
}
static struct spi_driver eeprom_93xx46_driver = {
.driver = {
.name = "93xx46",
.of_match_table = of_match_ptr(eeprom_93xx46_of_table),
},
.probe = eeprom_93xx46_probe,
.remove = eeprom_93xx46_remove,
};
module_spi_driver(eeprom_93xx46_driver);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Driver for 93xx46 EEPROMs");
MODULE_AUTHOR("Anatolij Gustschin <agust@denx.de>");
MODULE_ALIAS("spi:93xx46");