diff options
| author | David Brownell <dbrownell@users.sourceforge.net> | 2008-07-22 01:21:34 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-22 20:59:41 +0400 |
| commit | 1673ad52bd9a3c747e596a76e65c55981ea651e3 (patch) | |
| tree | 9e018b1d511a96f745fc870bfdf8bf53759c25ae /drivers/gpio/pcf857x.c | |
| parent | 0c36ec31473593aa937ff04f3b3b630e81512734 (diff) | |
| download | linux-1673ad52bd9a3c747e596a76e65c55981ea651e3.tar.xz | |
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: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/gpio/pcf857x.c')
| -rw-r--r-- | drivers/gpio/pcf857x.c | 33 |
1 files changed, 29 insertions, 4 deletions
diff --git a/drivers/gpio/pcf857x.c b/drivers/gpio/pcf857x.c index aa6cc8b2a2bc..d25d356c4f20 100644 --- a/drivers/gpio/pcf857x.c +++ b/drivers/gpio/pcf857x.c @@ -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; |