diff options
| author | Tapio Reijonen <tapio.reijonen@vaisala.com> | 2026-06-15 06:38:40 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-07-07 17:24:08 +0200 |
| commit | a483b1a91b33b7533280e7c3efd2bc1275caef18 (patch) | |
| tree | 79de82ed81fffe06201a3fdf874d1ee75d280cf3 /drivers | |
| parent | dc59e4fea9d83f03bad6bddf3fa2e52491777482 (diff) | |
serial: max310x: implement gpio_chip::get_direction()
It's strongly recommended for GPIO drivers to always implement the
.get_direction() callback - even when the direction is tracked in
software. The GPIO core emits a warning when the callback is missing
and a user reads the direction of a line, e.g. via
/sys/kernel/debug/gpio.
The MAX310X keeps the GPIO direction in the GPIOCFG register (a set bit
selects output), which the existing direction_input/output callbacks
already program, so the current direction can be read back directly.
Fixes: f65444187a66 ("serial: New serial driver MAX310X")
Cc: stable <stable@kernel.org>
Signed-off-by: Tapio Reijonen <tapio.reijonen@vaisala.com>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Reviewed-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://patch.msgid.link/20260615-b4-serial-max310x-gpio-get-direction-v2-1-4704ba2b181a@vaisala.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/tty/serial/max310x.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c index e28e3065c99d..92af02a39c7a 100644 --- a/drivers/tty/serial/max310x.c +++ b/drivers/tty/serial/max310x.c @@ -1244,6 +1244,17 @@ static int max310x_gpio_set(struct gpio_chip *chip, unsigned int offset, return 0; } +static int max310x_gpio_get_direction(struct gpio_chip *chip, unsigned int offset) +{ + struct max310x_port *s = gpiochip_get_data(chip); + struct uart_port *port = &s->p[offset / 4].port; + unsigned int val; + + val = max310x_port_read(port, MAX310X_GPIOCFG_REG); + + return val & BIT(offset % 4) ? GPIO_LINE_DIRECTION_OUT : GPIO_LINE_DIRECTION_IN; +} + static int max310x_gpio_direction_input(struct gpio_chip *chip, unsigned int offset) { struct max310x_port *s = gpiochip_get_data(chip); @@ -1447,6 +1458,7 @@ static int max310x_probe(struct device *dev, const struct max310x_devtype *devty s->gpio.owner = THIS_MODULE; s->gpio.parent = dev; s->gpio.label = devtype->name; + s->gpio.get_direction = max310x_gpio_get_direction; s->gpio.direction_input = max310x_gpio_direction_input; s->gpio.get = max310x_gpio_get; s->gpio.direction_output= max310x_gpio_direction_output; |