* [PATCH] gpiolib: don't clear FLAG_IS_OUT when emulating open-drain/open-source
@ 2019-09-10 8:21 Bartosz Golaszewski
[not found] ` <20190910104829.983FE2067B@mail.kernel.org>
2019-09-17 7:54 ` Bartosz Golaszewski
0 siblings, 2 replies; 3+ messages in thread
From: Bartosz Golaszewski @ 2019-09-10 8:21 UTC (permalink / raw)
To: Linus Walleij
Cc: linux-gpio, linux-kernel, Bartosz Golaszewski, stable, Kent Gibson
From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
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>
---
drivers/gpio/gpiolib.c | 27 +++++++++++++++++++--------
1 file changed, 19 insertions(+), 8 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index cca749010cd0..6bb4191d3844 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2769,8 +2769,10 @@ 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),
@@ -2778,8 +2780,10 @@ 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);
@@ -2787,6 +2791,17 @@ 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);
@@ -3147,8 +3162,6 @@ static void gpio_set_open_drain_value_commit(struct gpio_desc *desc, bool value)
if (value) {
err = chip->direction_input(chip, offset);
- if (!err)
- clear_bit(FLAG_IS_OUT, &desc->flags);
} else {
err = chip->direction_output(chip, offset, 0);
if (!err)
@@ -3178,8 +3191,6 @@ static void gpio_set_open_source_value_commit(struct gpio_desc *desc, bool value
set_bit(FLAG_IS_OUT, &desc->flags);
} else {
err = chip->direction_input(chip, offset);
- if (!err)
- clear_bit(FLAG_IS_OUT, &desc->flags);
}
trace_gpio_direction(desc_to_gpio(desc), !value, err);
if (err < 0)
--
2.21.0
^ permalink raw reply related [flat|nested] 3+ messages in thread[parent not found: <20190910104829.983FE2067B@mail.kernel.org>]
* Re: [PATCH] gpiolib: don't clear FLAG_IS_OUT when emulating open-drain/open-source
[not found] ` <20190910104829.983FE2067B@mail.kernel.org>
@ 2019-09-11 5:55 ` Bartosz Golaszewski
0 siblings, 0 replies; 3+ messages in thread
From: Bartosz Golaszewski @ 2019-09-11 5:55 UTC (permalink / raw)
To: Sasha Levin
Cc: Bartosz Golaszewski, Linus Walleij, linux-gpio, LKML, Stable # 4 . 20+
wt., 10 wrz 2019 o 12:48 Sasha Levin <sashal@kernel.org> napisał(a):
>
> Hi,
>
> [This is an automated email]
>
> This commit has been processed because it contains a "Fixes:" tag,
> fixing commit: c663e5f56737 gpio: support native single-ended hardware drivers.
>
> The bot has tested the following trees: v5.2.13, v4.19.71, v4.14.142, v4.9.191.
>
> v5.2.13: Build OK!
> v4.19.71: Build OK!
> v4.14.142: Failed to apply! Possible dependencies:
> 02e479808b5d ("gpio: Alter semantics of *raw* operations to actually be raw")
> fac9d8850a0c ("gpio: Get rid of _prefix and __prefixes")
>
> v4.9.191: Failed to apply! Possible dependencies:
> 02e479808b5d ("gpio: Alter semantics of *raw* operations to actually be raw")
> 0db0f26c2c5d ("pinctrl-sx150x: Convert driver to use regmap API")
> 2956b5d94a76 ("pinctrl / gpio: Introduce .set_config() callback for GPIO chips")
> 46a5c112a401 ("gpio: merrifield: Implement gpio_get_direction callback")
> 6489677f86c3 ("pinctrl-sx150x: Replace sx150x_*_cfg by means of regmap API")
> 6697546d650d ("pinctrl-sx150x: Add SX1503 specific data")
> 9e80f9064e73 ("pinctrl: Add SX150X GPIO Extender Pinctrl Driver")
> e3ba81206811 ("pinctrl-sx150x: Improve OF device matching code")
> e7a718f9b1c1 ("gpio: merrifield: Add support for hardware debouncer")
>
>
> NOTE: The patch will not be queued to stable trees until it is upstream.
>
> How should we proceed with this patch?
>
Once it's accepted, I'll prepare backports.
Bart
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] gpiolib: don't clear FLAG_IS_OUT when emulating open-drain/open-source
2019-09-10 8:21 [PATCH] gpiolib: don't clear FLAG_IS_OUT when emulating open-drain/open-source Bartosz Golaszewski
[not found] ` <20190910104829.983FE2067B@mail.kernel.org>
@ 2019-09-17 7:54 ` Bartosz Golaszewski
1 sibling, 0 replies; 3+ messages in thread
From: Bartosz Golaszewski @ 2019-09-17 7:54 UTC (permalink / raw)
To: Linus Walleij
Cc: open list:GPIO SUBSYSTEM, Linux Kernel Mailing List,
Bartosz Golaszewski, stable, Kent Gibson
wt., 10 wrz 2019 o 10:22 Bartosz Golaszewski <brgl@bgdev.pl> napisał(a):
>
> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
>
> 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>
> ---
> drivers/gpio/gpiolib.c | 27 +++++++++++++++++++--------
> 1 file changed, 19 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index cca749010cd0..6bb4191d3844 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -2769,8 +2769,10 @@ 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),
> @@ -2778,8 +2780,10 @@ 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);
> @@ -2787,6 +2791,17 @@ 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);
>
> @@ -3147,8 +3162,6 @@ static void gpio_set_open_drain_value_commit(struct gpio_desc *desc, bool value)
>
> if (value) {
> err = chip->direction_input(chip, offset);
> - if (!err)
> - clear_bit(FLAG_IS_OUT, &desc->flags);
> } else {
> err = chip->direction_output(chip, offset, 0);
> if (!err)
> @@ -3178,8 +3191,6 @@ static void gpio_set_open_source_value_commit(struct gpio_desc *desc, bool value
> set_bit(FLAG_IS_OUT, &desc->flags);
> } else {
> err = chip->direction_input(chip, offset);
> - if (!err)
> - clear_bit(FLAG_IS_OUT, &desc->flags);
> }
> trace_gpio_direction(desc_to_gpio(desc), !value, err);
> if (err < 0)
> --
> 2.21.0
>
Queued for fixes.
Bart
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-09-10 8:21 [PATCH] gpiolib: don't clear FLAG_IS_OUT when emulating open-drain/open-source Bartosz Golaszewski
[not found] ` <20190910104829.983FE2067B@mail.kernel.org>
2019-09-11 5:55 ` Bartosz Golaszewski
2019-09-17 7:54 ` Bartosz Golaszewski
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