Re: [PATCH v3 2/2] mmc: core: Add tunable delay before detecting card after card is inserted

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On 20 April 2018 at 08:59, Shawn Lin <shawn.lin@xxxxxxxxxxxxxx> wrote:
> Allow to use tunable delay before detecting card after card is inserted,
> which either comes from firmware node, or comes from debounce value
> passed on to mmc_gpiod_request_cd(). If the platform doesn't support
> debounce, then we fall back to use the debounce period as the delay,
> otherwise, it behaves the same as before that a HW debounce(if set) plus
> a 200ms hardcode delay before detecting the card.
>
> Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
>
> ---
>
> Changes in v3: None
> Changes in v2:
> - doesn't introduce new agrument for mmc_gpiod_request_cd and drop
>   the change for host drivers
>
>  drivers/mmc/core/host.c      | 7 +++++--
>  drivers/mmc/core/slot-gpio.c | 9 +++++++--
>  2 files changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> index 64b03d6..d281cbf 100644
> --- a/drivers/mmc/core/host.c
> +++ b/drivers/mmc/core/host.c
> @@ -179,7 +179,7 @@ static void mmc_retune_timer(struct timer_list *t)
>  int mmc_of_parse(struct mmc_host *host)
>  {
>         struct device *dev = host->parent;
> -       u32 bus_width, drv_type;
> +       u32 bus_width, drv_type, cd_delay_ms;
>         int ret;
>         bool cd_cap_invert, cd_gpio_invert = false;
>         bool ro_cap_invert, ro_gpio_invert = false;
> @@ -230,11 +230,14 @@ int mmc_of_parse(struct mmc_host *host)
>         } else {
>                 cd_cap_invert = device_property_read_bool(dev, "cd-inverted");
>
> +               if (device_property_read_u32(dev, "cd-delay-ms", &cd_delay_ms))
> +                       cd_delay_ms = 200;
> +
>                 if (device_property_read_bool(dev, "broken-cd"))
>                         host->caps |= MMC_CAP_NEEDS_POLL;
>
>                 ret = mmc_gpiod_request_cd(host, "cd", 0, true,
> -                                          0, &cd_gpio_invert);
> +                                          cd_delay_ms, &cd_gpio_invert);
>                 if (!ret)
>                         dev_info(host->parent, "Got CD GPIO\n");
>                 else if (ret != -ENOENT && ret != -ENOSYS)
> diff --git a/drivers/mmc/core/slot-gpio.c b/drivers/mmc/core/slot-gpio.c
> index 31f7dbb..2ef41be 100644
> --- a/drivers/mmc/core/slot-gpio.c
> +++ b/drivers/mmc/core/slot-gpio.c
> @@ -28,15 +28,17 @@ struct mmc_gpio {
>         irqreturn_t (*cd_gpio_isr)(int irq, void *dev_id);
>         char *ro_label;
>         char cd_label[0];
> +       u32 cd_delay_ms;
>  };
>
>  static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id)
>  {
>         /* Schedule a card detection after a debounce timeout */
>         struct mmc_host *host = dev_id;
> +       struct mmc_gpio *ctx = host->slot.handler_priv;
>
>         host->trigger_card_event = true;
> -       mmc_detect_change(host, msecs_to_jiffies(200));
> +       mmc_detect_change(host, msecs_to_jiffies(ctx->cd_delay_ms));
>
>         return IRQ_HANDLED;
>  }
> @@ -49,6 +51,7 @@ int mmc_gpio_alloc(struct mmc_host *host)
>
>         if (ctx) {
>                 ctx->ro_label = ctx->cd_label + len;
> +               ctx->cd_delay_ms = 200;
>                 snprintf(ctx->cd_label, len, "%s cd", dev_name(host->parent));
>                 snprintf(ctx->ro_label, len, "%s ro", dev_name(host->parent));
>                 host->slot.handler_priv = ctx;
> @@ -239,6 +242,8 @@ int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio,
>   * @debounce: debounce time in microseconds
>   * @gpio_invert: will return whether the GPIO line is inverted or not, set
>   * to NULL to ignore
> + * @cd_delay_ms: delay time in ms before detecting card after card insert
> + * event

This looks like a leftover from earlier versions...

>   *
>   * Use this function in place of mmc_gpio_request_cd() to use the GPIO
>   * descriptor API.  Note that it must be called prior to mmc_add_host()
> @@ -261,7 +266,7 @@ int mmc_gpiod_request_cd(struct mmc_host *host, const char *con_id,
>         if (debounce) {
>                 ret = gpiod_set_debounce(desc, debounce);
>                 if (ret < 0)
> -                       return ret;
> +                       ctx->cd_delay_ms = debounce;
>         }
>
>         if (gpio_invert)
> --
> 1.9.1
>
>

Besides the minor thing above, this looks good to me.

Kind regards
Uffe
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