[PATCH v2 1/2] Documentation: mmc: add optional cd-delay-ms property

[PATCH v2 1/2] Documentation: mmc: add optional cd-delay-ms property

[Shawn Lin]

slot-gpio uses a fixed delay, 200ms, before detecting card after the card
is inserted. 200ms doesn't work for some platforms, so some host drivers
added their own properties for parsing that from DT, for instance,
dw_mmc and pxamci. That being said, it should also be tunable when using
slog-gpio.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
---

Changes in v2: None

 Documentation/devicetree/bindings/mmc/mmc.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt
index 467cd7b..215b9a2 100644
--- a/Documentation/devicetree/bindings/mmc/mmc.txt
+++ b/Documentation/devicetree/bindings/mmc/mmc.txt
@@ -19,6 +19,8 @@ Optional properties:
 - wp-gpios: Specify GPIOs for write protection, see gpio binding
 - cd-inverted: when present, polarity on the CD line is inverted. See the note
   below for the case, when a GPIO is used for the CD line
+- cd-delay-ms: Set delay time before detecting card after card insert interrupt.
+  It's only valid when cd-gpios is present.
 - wp-inverted: when present, polarity on the WP line is inverted. See the note
   below for the case, when a GPIO is used for the WP line
 - disable-wp: When set no physical WP line is present. This property should
-- 
1.9.1

[PATCH v2 2/2] mmc: core: Add tunable delay before detecting card after card is inserted

[Shawn Lin]

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@rock-chips.com>

---

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
  *
  * 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

Re: [PATCH v2 1/2] Documentation: mmc: add optional cd-delay-ms property

[Rob Herring]

On Fri, Apr 13, 2018 at 10:18:44AM +0800, Shawn Lin wrote:
> slot-gpio uses a fixed delay, 200ms, before detecting card after the card
> is inserted. 200ms doesn't work for some platforms, so some host drivers
> added their own properties for parsing that from DT, for instance,
> dw_mmc and pxamci. That being said, it should also be tunable when using
> slog-gpio.

slot-gpio?

Or is it cd-gpios?

> 
> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
> ---
> 
> Changes in v2: None
> 
>  Documentation/devicetree/bindings/mmc/mmc.txt | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt
> index 467cd7b..215b9a2 100644
> --- a/Documentation/devicetree/bindings/mmc/mmc.txt
> +++ b/Documentation/devicetree/bindings/mmc/mmc.txt
> @@ -19,6 +19,8 @@ Optional properties:
>  - wp-gpios: Specify GPIOs for write protection, see gpio binding
>  - cd-inverted: when present, polarity on the CD line is inverted. See the note
>    below for the case, when a GPIO is used for the CD line
> +- cd-delay-ms: Set delay time before detecting card after card insert interrupt.
> +  It's only valid when cd-gpios is present.
>  - wp-inverted: when present, polarity on the WP line is inverted. See the note
>    below for the case, when a GPIO is used for the WP line
>  - disable-wp: When set no physical WP line is present. This property should
> -- 
> 1.9.1
> 
> 
> --
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> the body of a message to majordomo@vger.kernel.org
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Re: [PATCH v2 1/2] Documentation: mmc: add optional cd-delay-ms property

[Shawn Lin]

Hi Rob,

On 2018/4/17 3:26, Rob Herring wrote:
> On Fri, Apr 13, 2018 at 10:18:44AM +0800, Shawn Lin wrote:
>> slot-gpio uses a fixed delay, 200ms, before detecting card after the card
>> is inserted. 200ms doesn't work for some platforms, so some host drivers
>> added their own properties for parsing that from DT, for instance,
>> dw_mmc and pxamci. That being said, it should also be tunable when using
>> slog-gpio.
> 
> slot-gpio?
> 
> Or is it cd-gpios?

I think actually it shoule be cd-gpios. :)
Will update it.

> 
>>
>> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
>> ---
>>
>> Changes in v2: None
>>
>>   Documentation/devicetree/bindings/mmc/mmc.txt | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt
>> index 467cd7b..215b9a2 100644
>> --- a/Documentation/devicetree/bindings/mmc/mmc.txt
>> +++ b/Documentation/devicetree/bindings/mmc/mmc.txt
>> @@ -19,6 +19,8 @@ Optional properties:
>>   - wp-gpios: Specify GPIOs for write protection, see gpio binding
>>   - cd-inverted: when present, polarity on the CD line is inverted. See the note
>>     below for the case, when a GPIO is used for the CD line
>> +- cd-delay-ms: Set delay time before detecting card after card insert interrupt.
>> +  It's only valid when cd-gpios is present.
>>   - wp-inverted: when present, polarity on the WP line is inverted. See the note
>>     below for the case, when a GPIO is used for the WP line
>>   - disable-wp: When set no physical WP line is present. This property should
>> -- 
>> 1.9.1
>>
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe devicetree" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> 
> 

Re: [PATCH v2 2/2] mmc: core: Add tunable delay before detecting card after card is inserted

[Linus Walleij]

On Fri, Apr 13, 2018 at 4:18 AM, Shawn Lin <shawn.lin@rock-chips.com> 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@rock-chips.com>
>
> ---
>
> Changes in v2:
> - doesn't introduce new agrument for mmc_gpiod_request_cd and drop
>   the change for host drivers

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

Yours,
Linus Walleij