Re: [PATCH] tty: serial: cpm_uart: Fix behaviour for non existing GPIOs
Hi Christophe!
On Sat, Jun 6, 2020 at 9:30 AM Christophe Leroy
wrote:
> gpiod = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
>
> - if (gpiod) {
> + if (!IS_ERR_OR_NULL(gpiod)) {
> if (i == GPIO_RTS || i == GPIO_DTR)
> ret = gpiod_direction_output(gpiod, 0);
> else
This code, and the way descriptors are used in the driver leads
me to believe that the right solution is to use the optional
call with a hard error check:
gpiod = devm_gpiod_get_index_optional(...);
if (IS_ERR(gpiod))
return PTR_ERR(gpiod);
if (gpiod) {
... followed by the old code ...
This makes sure that the array member is left NULL if there is no
GPIO on this line, and all other errors, such as -EPROBE_DEFER
which currently absolutely does not work, will lead to us properly
exiting with an error.
Yours,
Linus Walleij
Re: [PATCH] tty: serial: cpm_uart: Fix behaviour for non existing GPIOs
On Sat, Jun 06, 2020 at 07:30:21AM +, Christophe Leroy wrote:
> devm_gpiod_get_index() doesn't return NULL but -ENOENT when the
> requested GPIO doesn't exist, leading to the following messages:
>
> [2.742468] gpiod_direction_input: invalid GPIO (errorpointer)
> [2.748147] can't set direction for gpio #2: -2
> [2.753081] gpiod_direction_input: invalid GPIO (errorpointer)
> [2.758724] can't set direction for gpio #3: -2
> [2.763666] gpiod_direction_output: invalid GPIO (errorpointer)
> [2.769394] can't set direction for gpio #4: -2
> [2.774341] gpiod_direction_input: invalid GPIO (errorpointer)
> [2.779981] can't set direction for gpio #5: -2
> [2.784545] ff000a20.serial: ttyCPM1 at MMIO 0xfff00a20 (irq = 39,
> base_baud = 825) is a CPM UART
>
> Use IS_ERR_OR_NULL() to properly check gpiod validity.
Why check for NULL at all?
> Fixes: 97cbaf2c829b ("tty: serial: cpm_uart: Convert to use GPIO descriptors")
> Cc: sta...@vger.kernel.org
> Cc: Linus Walleij
> Signed-off-by: Christophe Leroy
> ---
> drivers/tty/serial/cpm_uart/cpm_uart_core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/tty/serial/cpm_uart/cpm_uart_core.c
> b/drivers/tty/serial/cpm_uart/cpm_uart_core.c
> index a04f74d2e854..3cbe24802296 100644
> --- a/drivers/tty/serial/cpm_uart/cpm_uart_core.c
> +++ b/drivers/tty/serial/cpm_uart/cpm_uart_core.c
> @@ -1217,7 +1217,7 @@ static int cpm_uart_init_port(struct device_node *np,
>
> gpiod = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
>
> - if (gpiod) {
> + if (!IS_ERR_OR_NULL(gpiod)) {
> if (i == GPIO_RTS || i == GPIO_DTR)
> ret = gpiod_direction_output(gpiod, 0);
> else
Johan
[PATCH] tty: serial: cpm_uart: Fix behaviour for non existing GPIOs
devm_gpiod_get_index() doesn't return NULL but -ENOENT when the
requested GPIO doesn't exist, leading to the following messages:
[2.742468] gpiod_direction_input: invalid GPIO (errorpointer)
[2.748147] can't set direction for gpio #2: -2
[2.753081] gpiod_direction_input: invalid GPIO (errorpointer)
[2.758724] can't set direction for gpio #3: -2
[2.763666] gpiod_direction_output: invalid GPIO (errorpointer)
[2.769394] can't set direction for gpio #4: -2
[2.774341] gpiod_direction_input: invalid GPIO (errorpointer)
[2.779981] can't set direction for gpio #5: -2
[2.784545] ff000a20.serial: ttyCPM1 at MMIO 0xfff00a20 (irq = 39, base_baud
= 825) is a CPM UART
Use IS_ERR_OR_NULL() to properly check gpiod validity.
Fixes: 97cbaf2c829b ("tty: serial: cpm_uart: Convert to use GPIO descriptors")
Cc: sta...@vger.kernel.org
Cc: Linus Walleij
Signed-off-by: Christophe Leroy
---
drivers/tty/serial/cpm_uart/cpm_uart_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/serial/cpm_uart/cpm_uart_core.c
b/drivers/tty/serial/cpm_uart/cpm_uart_core.c
index a04f74d2e854..3cbe24802296 100644
--- a/drivers/tty/serial/cpm_uart/cpm_uart_core.c
+++ b/drivers/tty/serial/cpm_uart/cpm_uart_core.c
@@ -1217,7 +1217,7 @@ static int cpm_uart_init_port(struct device_node *np,
gpiod = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
- if (gpiod) {
+ if (!IS_ERR_OR_NULL(gpiod)) {
if (i == GPIO_RTS || i == GPIO_DTR)
ret = gpiod_direction_output(gpiod, 0);
else
--
2.25.0
