Commit 1673ad52 authored by David Brownell's avatar David Brownell Committed by Linus Torvalds
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gpio: pcf857x: add lock and handle more chips 



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: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0c36ec31

drivers/gpio/Kconfig

+3 −2
Original line number Diff line number Diff line
@@ -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

drivers/gpio/pcf857x.c

+29 −4
Original line number Diff line number Diff line
@@ -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;

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