unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
1
Fork 0
Code Pull requests 5 Wiki Activity

leds: turris-omnia: Drop unnecessary mutex locking

Browse source 
Do not lock driver mutex in the global LED panel brightness sysfs
accessors brightness_show() and brightness_store().

The mutex locking is unnecessary here. The I2C transfers are guarded by
I2C core locking mechanism, and the LED commands itself do not interfere
with other commands.

Fixes: 089381b27a ("leds: initial support for Turris Omnia LEDs")
Signed-off-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230802160748.11208-2-kabel@kernel.org
Signed-off-by: Lee Jones <lee@kernel.org>
This commit is contained in:
Marek Behún 2023-08-02 18:07:43 +02:00 committed by Lee Jones
parent 72a29725b6
commit 760b6b7925
1 changed files with 1 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

11
drivers/leds/leds-turris-omnia.c
View file

@ -156,12 +156,9 @@ static ssize_t brightness_show(struct device *dev, struct device_attribute *a,
char *buf)
{
struct i2c_client *client = to_i2c_client(dev);
struct omnia_leds *leds = i2c_get_clientdata(client);
int ret;
mutex_lock(&leds->lock);
ret = i2c_smbus_read_byte_data(client, CMD_LED_GET_BRIGHTNESS);
mutex_unlock(&leds->lock);
if (ret < 0)
return ret;
@ -173,7 +170,6 @@ static ssize_t brightness_store(struct device *dev, struct device_attribute *a,
const char *buf, size_t count)
{
struct i2c_client *client = to_i2c_client(dev);
struct omnia_leds *leds = i2c_get_clientdata(client);
unsigned long brightness;
int ret;
@ -183,15 +179,10 @@ static ssize_t brightness_store(struct device *dev, struct device_attribute *a,
if (brightness > 100)
return -EINVAL;
mutex_lock(&leds->lock);
ret = i2c_smbus_write_byte_data(client, CMD_LED_SET_BRIGHTNESS,
(u8)brightness);
mutex_unlock(&leds->lock);
if (ret < 0)
return ret;
return count;
return ret < 0 ? ret : count;
}
static DEVICE_ATTR_RW(brightness);