[PATCH] mmc: mmc_spi: Use proper debounce time for CD GPIO

[PATCH] mmc: mmc_spi: Use proper debounce time for CD GPIO

[Thierry Reding]

From: Thierry Reding <treding@nvidia.com>

According to the comment, board files used to specify 1 ms for the
debounce time. gpiod_set_debounce() needs the debounce time to be
specified in units of microseconds, so make sure to multiply the value
by 1000.

Note that, according to the git log, the board files actually did
specify 1 us for bounce times, but that seems really low. Device tree
bindings for this type of GPIO typically specify the debounce times in
milliseconds, so setting this default value to 1 ms seems like it would
be somewhat safer.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 drivers/mmc/host/mmc_spi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
index 66e354d51ee9..74c6cfbf9172 100644
--- a/drivers/mmc/host/mmc_spi.c
+++ b/drivers/mmc/host/mmc_spi.c
@@ -1421,7 +1421,7 @@ static int mmc_spi_probe(struct spi_device *spi)
 	 * Index 0 is card detect
 	 * Old boardfiles were specifying 1 ms as debounce
 	 */
-	status = mmc_gpiod_request_cd(mmc, NULL, 0, false, 1, NULL);
+	status = mmc_gpiod_request_cd(mmc, NULL, 0, false, 1000, NULL);
 	if (status == -EPROBE_DEFER)
 		goto fail_add_host;
 	if (!status) {
-- 
2.23.0

Re: [PATCH] mmc: mmc_spi: Use proper debounce time for CD GPIO

[Pavel Machek]

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On Fri 2019-11-08 17:09:00, Thierry Reding wrote:
> From: Thierry Reding <treding@nvidia.com>
> 
> According to the comment, board files used to specify 1 ms for the
> debounce time. gpiod_set_debounce() needs the debounce time to be
> specified in units of microseconds, so make sure to multiply the value
> by 1000.
> 
> Note that, according to the git log, the board files actually did
> specify 1 us for bounce times, but that seems really low. Device tree
> bindings for this type of GPIO typically specify the debounce times in
> milliseconds, so setting this default value to 1 ms seems like it would
> be somewhat safer.
> 
> Signed-off-by: Thierry Reding <treding@nvidia.com>

Acked-by: Pavel Machek <pavel@denx.de>

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

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Re: [PATCH] mmc: mmc_spi: Use proper debounce time for CD GPIO

[Linus Walleij]

On Fri, Nov 8, 2019 at 5:09 PM Thierry Reding <thierry.reding@gmail.com> wrote:

> From: Thierry Reding <treding@nvidia.com>
>
> According to the comment, board files used to specify 1 ms for the
> debounce time. gpiod_set_debounce() needs the debounce time to be
> specified in units of microseconds, so make sure to multiply the value
> by 1000.
>
> Note that, according to the git log, the board files actually did
> specify 1 us for bounce times, but that seems really low. Device tree
> bindings for this type of GPIO typically specify the debounce times in
> milliseconds, so setting this default value to 1 ms seems like it would
> be somewhat safer.
>
> Signed-off-by: Thierry Reding <treding@nvidia.com>

Makes perfect sense.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij

Re: [PATCH] mmc: mmc_spi: Use proper debounce time for CD GPIO

[Ulf Hansson]

On Fri, 8 Nov 2019 at 17:09, Thierry Reding <thierry.reding@gmail.com> wrote:
>
> From: Thierry Reding <treding@nvidia.com>
>
> According to the comment, board files used to specify 1 ms for the
> debounce time. gpiod_set_debounce() needs the debounce time to be
> specified in units of microseconds, so make sure to multiply the value
> by 1000.
>
> Note that, according to the git log, the board files actually did
> specify 1 us for bounce times, but that seems really low. Device tree
> bindings for this type of GPIO typically specify the debounce times in
> milliseconds, so setting this default value to 1 ms seems like it would
> be somewhat safer.
>
> Signed-off-by: Thierry Reding <treding@nvidia.com>

Applied for next, thanks!

Kind regards
Uffe



> ---
>  drivers/mmc/host/mmc_spi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
> index 66e354d51ee9..74c6cfbf9172 100644
> --- a/drivers/mmc/host/mmc_spi.c
> +++ b/drivers/mmc/host/mmc_spi.c
> @@ -1421,7 +1421,7 @@ static int mmc_spi_probe(struct spi_device *spi)
>          * Index 0 is card detect
>          * Old boardfiles were specifying 1 ms as debounce
>          */
> -       status = mmc_gpiod_request_cd(mmc, NULL, 0, false, 1, NULL);
> +       status = mmc_gpiod_request_cd(mmc, NULL, 0, false, 1000, NULL);
>         if (status == -EPROBE_DEFER)
>                 goto fail_add_host;
>         if (!status) {
> --
> 2.23.0
>