redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

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: c663e5f567 ("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>
alistair/sunxi64-5.4-dsi
Bartosz Golaszewski 2019-10-01 11:44:53 +02:00
parent 54ecb8f702
commit e735244e2c
1 changed files with 19 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
drivers/gpio/gpiolib.c
View File

@ -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)