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

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On 12 April 2018 at 03:20, Shawn Lin <shawn.lin@xxxxxxxxxxxxxx> wrote:
> Allow to use tunable delay before detecting card after card is inserted
> either from firmware, or argument passing to mmc_gpiod_request_cd(). The
> default value is 200ms as before, if cd-delay-ms isn't present but using
> mmc_gpiod_request_cd() to request slot-gpio interrupt.

Exactly why doesn't the 200 ms delay works?

It seems like the proper method is instead to use a gpio debouncing
time. mmc-slot-gpio already deals with that, but we are defaulting to
use zero as debounce period, when mmc_gpiod_request_cd() is called
from mmc_of_parse().

Kind regards
Uffe

>
> Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
> ---
>
>  drivers/mmc/core/host.c           |  7 +++++--
>  drivers/mmc/core/slot-gpio.c      | 11 +++++++++--
>  drivers/mmc/host/davinci_mmc.c    |  2 +-
>  drivers/mmc/host/mmci.c           |  2 +-
>  drivers/mmc/host/sdhci-acpi.c     |  2 +-
>  drivers/mmc/host/sdhci-pci-core.c |  3 ++-
>  include/linux/mmc/slot-gpio.h     |  3 ++-
>  7 files changed, 21 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> index 64b03d6..cb8babc 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);
> +                                          0, &cd_gpio_invert, cd_delay_ms);
>                 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..baa6e8d 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
>   *
>   * 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()
> @@ -248,7 +253,8 @@ int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio,
>   */
>  int mmc_gpiod_request_cd(struct mmc_host *host, const char *con_id,
>                          unsigned int idx, bool override_active_level,
> -                        unsigned int debounce, bool *gpio_invert)
> +                        unsigned int debounce, bool *gpio_invert,
> +                        u32 cd_delay_ms)
>  {
>         struct mmc_gpio *ctx = host->slot.handler_priv;
>         struct gpio_desc *desc;
> @@ -269,6 +275,7 @@ int mmc_gpiod_request_cd(struct mmc_host *host, const char *con_id,
>
>         ctx->override_cd_active_level = override_active_level;
>         ctx->cd_gpio = desc;
> +       ctx->cd_delay_ms = cd_delay_ms;
>
>         return 0;
>  }
> diff --git a/drivers/mmc/host/davinci_mmc.c b/drivers/mmc/host/davinci_mmc.c
> index 8e36317..fcff397 100644
> --- a/drivers/mmc/host/davinci_mmc.c
> +++ b/drivers/mmc/host/davinci_mmc.c
> @@ -1187,7 +1187,7 @@ static int mmc_davinci_parse_pdata(struct mmc_host *mmc)
>                 mmc->caps |= pdata->caps;
>
>         /* Register a cd gpio, if there is not one, enable polling */
> -       ret = mmc_gpiod_request_cd(mmc, "cd", 0, false, 0, NULL);
> +       ret = mmc_gpiod_request_cd(mmc, "cd", 0, false, 0, NULL, 200);
>         if (ret == -EPROBE_DEFER)
>                 return ret;
>         else if (ret)
> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
> index 70b0df8..0771c4f 100644
> --- a/drivers/mmc/host/mmci.c
> +++ b/drivers/mmc/host/mmci.c
> @@ -1827,7 +1827,7 @@ static int mmci_probe(struct amba_device *dev,
>          * silently of these do not exist and proceed to try platform data
>          */
>         if (!np) {
> -               ret = mmc_gpiod_request_cd(mmc, "cd", 0, false, 0, NULL);
> +               ret = mmc_gpiod_request_cd(mmc, "cd", 0, false, 0, NULL, 200);
>                 if (ret < 0) {
>                         if (ret == -EPROBE_DEFER)
>                                 goto clk_disable;
> diff --git a/drivers/mmc/host/sdhci-acpi.c b/drivers/mmc/host/sdhci-acpi.c
> index 32321bd..4157a29 100644
> --- a/drivers/mmc/host/sdhci-acpi.c
> +++ b/drivers/mmc/host/sdhci-acpi.c
> @@ -718,7 +718,7 @@ static int sdhci_acpi_probe(struct platform_device *pdev)
>         if (sdhci_acpi_flag(c, SDHCI_ACPI_SD_CD)) {
>                 bool v = sdhci_acpi_flag(c, SDHCI_ACPI_SD_CD_OVERRIDE_LEVEL);
>
> -               err = mmc_gpiod_request_cd(host->mmc, NULL, 0, v, 0, NULL);
> +               err = mmc_gpiod_request_cd(host->mmc, NULL, 0, v, 0, NULL, 200);
>                 if (err) {
>                         if (err == -EPROBE_DEFER)
>                                 goto err_free;
> diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
> index 787434e..7842a67 100644
> --- a/drivers/mmc/host/sdhci-pci-core.c
> +++ b/drivers/mmc/host/sdhci-pci-core.c
> @@ -1715,7 +1715,8 @@ static struct sdhci_pci_slot *sdhci_pci_probe_slot(
>
>         if (slot->cd_idx >= 0) {
>                 ret = mmc_gpiod_request_cd(host->mmc, NULL, slot->cd_idx,
> -                                          slot->cd_override_level, 0, NULL);
> +                                          slot->cd_override_level, 0, NULL,
> +                                          200);
>                 if (ret == -EPROBE_DEFER)
>                         goto remove;
>
> diff --git a/include/linux/mmc/slot-gpio.h b/include/linux/mmc/slot-gpio.h
> index 06607c5..b13f3a9 100644
> --- a/include/linux/mmc/slot-gpio.h
> +++ b/include/linux/mmc/slot-gpio.h
> @@ -25,7 +25,8 @@ int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio,
>
>  int mmc_gpiod_request_cd(struct mmc_host *host, const char *con_id,
>                          unsigned int idx, bool override_active_level,
> -                        unsigned int debounce, bool *gpio_invert);
> +                        unsigned int debounce, bool *gpio_invert,
> +                        u32 cd_delay);
>  int mmc_gpiod_request_ro(struct mmc_host *host, const char *con_id,
>                          unsigned int idx, bool override_active_level,
>                          unsigned int debounce, bool *gpio_invert);
> --
> 1.9.1
>
>
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