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authorBartosz Golaszewski <bgolaszewski@baylibre.com>2019-10-01 12:44:53 +0300
committerBartosz Golaszewski <bgolaszewski@baylibre.com>2019-10-01 12:44:53 +0300
commite735244e2cf068f98b6384681a38993e0517a838 (patch)
treed754d7427e44d9f89a64c9ed2a6c216dbdf60f6c /drivers/gpio
parent54ecb8f7028c5eb3d740bb82b0f1d90f2df63c5c (diff)
downloadlinux-e735244e2cf068f98b6384681a38993e0517a838.tar.xz
gpiolib: don't clear FLAG_IS_OUT when emulating open-drain/open-source
When emulating open-drain/open-source by not actively driving the output lines - we're simply changing their mode to input. This is wrong as it will then make it impossible to change the value of such line - it's now considered to actually be in input mode. If we want to still use the direction_input() callback for simplicity then we need to set FLAG_IS_OUT manually in gpiod_direction_output() and not clear it in gpio_set_open_drain_value_commit() and gpio_set_open_source_value_commit(). Fixes: c663e5f56737 ("gpio: support native single-ended hardware drivers") Cc: stable@vger.kernel.org Reported-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Diffstat (limited to 'drivers/gpio')
-rw-r--r--drivers/gpio/gpiolib.c27
1 files changed, 19 insertions, 8 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index bdbc1649eafa..5833e4f380d6 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -3070,8 +3070,10 @@ int gpiod_direction_output(struct gpio_desc *desc, int value)
if (!ret)
goto set_output_value;
/* Emulate open drain by not actively driving the line high */
- if (value)
- return gpiod_direction_input(desc);
+ if (value) {
+ ret = gpiod_direction_input(desc);
+ goto set_output_flag;
+ }
}
else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) {
ret = gpio_set_config(gc, gpio_chip_hwgpio(desc),
@@ -3079,8 +3081,10 @@ int gpiod_direction_output(struct gpio_desc *desc, int value)
if (!ret)
goto set_output_value;
/* Emulate open source by not actively driving the line low */
- if (!value)
- return gpiod_direction_input(desc);
+ if (!value) {
+ ret = gpiod_direction_input(desc);
+ goto set_output_flag;
+ }
} else {
gpio_set_config(gc, gpio_chip_hwgpio(desc),
PIN_CONFIG_DRIVE_PUSH_PULL);
@@ -3088,6 +3092,17 @@ int gpiod_direction_output(struct gpio_desc *desc, int value)
set_output_value:
return gpiod_direction_output_raw_commit(desc, value);
+
+set_output_flag:
+ /*
+ * When emulating open-source or open-drain functionalities by not
+ * actively driving the line (setting mode to input) we still need to
+ * set the IS_OUT flag or otherwise we won't be able to set the line
+ * value anymore.
+ */
+ if (ret == 0)
+ set_bit(FLAG_IS_OUT, &desc->flags);
+ return ret;
}
EXPORT_SYMBOL_GPL(gpiod_direction_output);
@@ -3448,8 +3463,6 @@ static void gpio_set_open_drain_value_commit(struct gpio_desc *desc, bool value)
if (value) {
ret = chip->direction_input(chip, offset);
- if (!ret)
- clear_bit(FLAG_IS_OUT, &desc->flags);
} else {
ret = chip->direction_output(chip, offset, 0);
if (!ret)
@@ -3479,8 +3492,6 @@ static void gpio_set_open_source_value_commit(struct gpio_desc *desc, bool value
set_bit(FLAG_IS_OUT, &desc->flags);
} else {
ret = chip->direction_input(chip, offset);
- if (!ret)
- clear_bit(FLAG_IS_OUT, &desc->flags);
}
trace_gpio_direction(desc_to_gpio(desc), !value, ret);
if (ret < 0)