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gpiolib: don't allow setting values on input lines

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Some drivers as well as the character device and sysfs code check
whether the line actually is in output mode before allowing the user to
set a value.

However, GPIO value setters now return integer values and can indicate
failures. This allows us to move these checks into the core code.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250311-gpio-set-check-output-v1-1-d971bca9e6fa@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
This commit is contained in:
Bartosz Golaszewski 2025-03-11 15:19:51 +01:00
parent 0af2f6be1b
commit 92ac7de317
3 changed files with 17 additions and 10 deletions
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3
drivers/gpio/gpiolib-cdev.c
View file

@ -1366,9 +1366,6 @@ static long linereq_set_values(struct linereq *lr, void __user *ip)
/* scan requested lines to determine the subset to be set */
for (num_set = 0, i = 0; i < lr->num_lines; i++) {
if (lv.mask & BIT_ULL(i)) {
/* setting inputs is not allowed */
if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags))
return -EPERM;
/* add to compacted values */
if (lv.bits & BIT_ULL(i))
__set_bit(num_set, vals);

12
drivers/gpio/gpiolib-sysfs.c
View file

@ -134,16 +134,14 @@ static ssize_t value_store(struct device *dev,
long value;
status = kstrtol(buf, 0, &value);
guard(mutex)(&data->mutex);
if (!test_bit(FLAG_IS_OUT, &desc->flags))
return -EPERM;
if (status)
return status;
gpiod_set_value_cansleep(desc, value);
guard(mutex)(&data->mutex);
status = gpiod_set_value_cansleep(desc, value);
if (status)
return status;
return size;
}

12
drivers/gpio/gpiolib.c
View file

@ -3593,6 +3593,9 @@ static int gpio_set_open_source_value_commit(struct gpio_desc *desc, bool value)
static int gpiod_set_raw_value_commit(struct gpio_desc *desc, bool value)
{
if (unlikely(!test_bit(FLAG_IS_OUT, &desc->flags)))
return -EPERM;
CLASS(gpio_chip_guard, guard)(desc);
if (!guard.gc)
return -ENODEV;
@ -3664,6 +3667,12 @@ int gpiod_set_array_value_complex(bool raw, bool can_sleep,
if (!can_sleep)
WARN_ON(array_info->gdev->can_sleep);
for (i = 0; i < array_size; i++) {
if (unlikely(!test_bit(FLAG_IS_OUT,
&desc_array[i]->flags)))
return -EPERM;
}
guard(srcu)(&array_info->gdev->srcu);
gc = srcu_dereference(array_info->gdev->chip,
&array_info->gdev->srcu);
@ -3723,6 +3732,9 @@ int gpiod_set_array_value_complex(bool raw, bool can_sleep,
int hwgpio = gpio_chip_hwgpio(desc);
int value = test_bit(i, value_bitmap);
if (unlikely(!test_bit(FLAG_IS_OUT, &desc->flags)))
return -EPERM;
/*
* Pins applicable for fast input but not for
* fast output processing may have been already