redonkable/remarkable-linux
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gpio: pcf857x: add lock and handle more chips

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Two small updates to the pcf857x driver: (a) the max732[89] chips are
also second sources for the pcf8574/a, and (b) add a mutex to prevent
trashing the cached state.  Adding the lock is effectively a bugfix,
although it seems unlikely that anyone would have run into the issue it
protects against.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Brownell 2008-07-21 14:21:34 -07:00 committed by Linus Torvalds
parent 0c36ec3147
commit 1673ad52bd
2 changed files with 32 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
drivers/gpio/Kconfig
View file

@ -45,7 +45,7 @@ config GPIO_PCA953X
will be called pca953x.
config GPIO_PCF857X
tristate "PCF857x, PCA857x, and PCA967x I2C GPIO expanders"
tristate "PCF857x, PCA{85,96}7x, and MAX732[89] I2C GPIO expanders"
depends on I2C
help
Say yes here to provide access to most "quasi-bidirectional" I2C
@ -54,7 +54,8 @@ config GPIO_PCF857X
some of them. Compatible models include:
8 bits: pcf8574, pcf8574a, pca8574, pca8574a,
pca9670, pca9672, pca9674, pca9674a
pca9670, pca9672, pca9674, pca9674a,
max7328, max7329
16 bits: pcf8575, pcf8575c, pca8575,
pca9671, pca9673, pca9675

33
drivers/gpio/pcf857x.c
View file

@ -37,6 +37,8 @@ static const struct i2c_device_id pcf857x_id[] = {
{ "pca9671", 16 },
{ "pca9673", 16 },
{ "pca9675", 16 },
{ "max7328", 8 },
{ "max7329", 8 },
{ }
};
MODULE_DEVICE_TABLE(i2c, pcf857x_id);
@ -56,6 +58,7 @@ MODULE_DEVICE_TABLE(i2c, pcf857x_id);
struct pcf857x {
struct gpio_chip chip;
struct i2c_client *client;
struct mutex lock; /* protect 'out' */
unsigned out; /* software latch */
};
@ -66,9 +69,14 @@ struct pcf857x {
static int pcf857x_input8(struct gpio_chip *chip, unsigned offset)
{
struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
int status;
mutex_lock(&gpio->lock);
gpio->out |= (1 << offset);
return i2c_smbus_write_byte(gpio->client, gpio->out);
status = i2c_smbus_write_byte(gpio->client, gpio->out);
mutex_unlock(&gpio->lock);
return status;
}
static int pcf857x_get8(struct gpio_chip *chip, unsigned offset)
@ -84,12 +92,17 @@ static int pcf857x_output8(struct gpio_chip *chip, unsigned offset, int value)
{
struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
unsigned bit = 1 << offset;
int status;
mutex_lock(&gpio->lock);
if (value)
gpio->out |= bit;
else
gpio->out &= ~bit;
return i2c_smbus_write_byte(gpio->client, gpio->out);
status = i2c_smbus_write_byte(gpio->client, gpio->out);
mutex_unlock(&gpio->lock);
return status;
}
static void pcf857x_set8(struct gpio_chip *chip, unsigned offset, int value)
@ -124,9 +137,14 @@ static int i2c_read_le16(struct i2c_client *client)
static int pcf857x_input16(struct gpio_chip *chip, unsigned offset)
{
struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
int status;
mutex_lock(&gpio->lock);
gpio->out |= (1 << offset);
return i2c_write_le16(gpio->client, gpio->out);
status = i2c_write_le16(gpio->client, gpio->out);
mutex_unlock(&gpio->lock);
return status;
}
static int pcf857x_get16(struct gpio_chip *chip, unsigned offset)
@ -142,12 +160,17 @@ static int pcf857x_output16(struct gpio_chip *chip, unsigned offset, int value)
{
struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
unsigned bit = 1 << offset;
int status;
mutex_lock(&gpio->lock);
if (value)
gpio->out |= bit;
else
gpio->out &= ~bit;
return i2c_write_le16(gpio->client, gpio->out);
status = i2c_write_le16(gpio->client, gpio->out);
mutex_unlock(&gpio->lock);
return status;
}
static void pcf857x_set16(struct gpio_chip *chip, unsigned offset, int value)
@ -173,6 +196,8 @@ static int pcf857x_probe(struct i2c_client *client,
if (!gpio)
return -ENOMEM;
mutex_init(&gpio->lock);
gpio->chip.base = pdata->gpio_base;
gpio->chip.can_sleep = 1;
gpio->chip.owner = THIS_MODULE;