The patch titled
drivers/gpio/pca953x.c: add a mutex to fix race condition
has been removed from the -mm tree. Its filename was
drivers-gpio-pca953xc-add-a-mutex-to-fix-race-condition.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: drivers/gpio/pca953x.c: add a mutex to fix race condition
From: Roland Stigge <stigge@xxxxxxxxx>
Add a mutex to register communication and handling. Without the mutex,
GPIOs didn't switch as expected when toggled in a fast sequence of status
changes of multiple outputs.
Signed-off-by: Roland Stigge <stigge@xxxxxxxxx>
Cc: Grant Likely <grant.likely@xxxxxxxxxxxx>
Cc: Marc Zyngier <maz@xxxxxxxxxxxxxxx>
Cc: Ben Gardner <bgardner@xxxxxxxxxx>
Cc: eric miao <eric.y.miao@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/gpio/pca953x.c | 28 ++++++++++++++++++++++------
1 file changed, 22 insertions(+), 6 deletions(-)
diff -puN drivers/gpio/pca953x.c~drivers-gpio-pca953xc-add-a-mutex-to-fix-race-condition drivers/gpio/pca953x.c
--- a/drivers/gpio/pca953x.c~drivers-gpio-pca953xc-add-a-mutex-to-fix-race-condition
+++ a/drivers/gpio/pca953x.c
@@ -60,6 +60,7 @@ struct pca953x_chip {
unsigned gpio_start;
uint16_t reg_output;
uint16_t reg_direction;
+ struct mutex i2c_lock;
#ifdef CONFIG_GPIO_PCA953X_IRQ
struct mutex irq_lock;
@@ -119,13 +120,17 @@ static int pca953x_gpio_direction_input(
chip = container_of(gc, struct pca953x_chip, gpio_chip);
+ mutex_lock(&chip->i2c_lock);
reg_val = chip->reg_direction | (1u << off);
ret = pca953x_write_reg(chip, PCA953X_DIRECTION, reg_val);
if (ret)
- return ret;
+ goto exit;
chip->reg_direction = reg_val;
- return 0;
+ ret = 0;
+exit:
+ mutex_unlock(&chip->i2c_lock);
+ return ret;
}
static int pca953x_gpio_direction_output(struct gpio_chip *gc,
@@ -137,6 +142,7 @@ static int pca953x_gpio_direction_output
chip = container_of(gc, struct pca953x_chip, gpio_chip);
+ mutex_lock(&chip->i2c_lock);
/* set output level */
if (val)
reg_val = chip->reg_output | (1u << off);
@@ -145,7 +151,7 @@ static int pca953x_gpio_direction_output
ret = pca953x_write_reg(chip, PCA953X_OUTPUT, reg_val);
if (ret)
- return ret;
+ goto exit;
chip->reg_output = reg_val;
@@ -153,10 +159,13 @@ static int pca953x_gpio_direction_output
reg_val = chip->reg_direction & ~(1u << off);
ret = pca953x_write_reg(chip, PCA953X_DIRECTION, reg_val);
if (ret)
- return ret;
+ goto exit;
chip->reg_direction = reg_val;
- return 0;
+ ret = 0;
+exit:
+ mutex_unlock(&chip->i2c_lock);
+ return ret;
}
static int pca953x_gpio_get_value(struct gpio_chip *gc, unsigned off)
@@ -167,7 +176,9 @@ static int pca953x_gpio_get_value(struct
chip = container_of(gc, struct pca953x_chip, gpio_chip);
+ mutex_lock(&chip->i2c_lock);
ret = pca953x_read_reg(chip, PCA953X_INPUT, ®_val);
+ mutex_unlock(&chip->i2c_lock);
if (ret < 0) {
/* NOTE: diagnostic already emitted; that's all we should
* do unless gpio_*_value_cansleep() calls become different
@@ -187,6 +198,7 @@ static void pca953x_gpio_set_value(struc
chip = container_of(gc, struct pca953x_chip, gpio_chip);
+ mutex_lock(&chip->i2c_lock);
if (val)
reg_val = chip->reg_output | (1u << off);
else
@@ -194,9 +206,11 @@ static void pca953x_gpio_set_value(struc
ret = pca953x_write_reg(chip, PCA953X_OUTPUT, reg_val);
if (ret)
- return;
+ goto exit;
chip->reg_output = reg_val;
+exit:
+ mutex_unlock(&chip->i2c_lock);
}
static void pca953x_setup_gpio(struct pca953x_chip *chip, int gpios)
@@ -517,6 +531,8 @@ static int __devinit pca953x_probe(struc
chip->names = pdata->names;
+ mutex_init(&chip->i2c_lock);
+
/* initialize cached registers from their original values.
* we can't share this chip with another i2c master.
*/
_
Patches currently in -mm which might be from stigge@xxxxxxxxx are
origin.patch
linux-next.patch
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