diff mbox

[v2,10/22] mmc: tmio: support IP-builtin card detection logic

Message ID 1511540697-27387-11-git-send-email-yamada.masahiro@socionext.com (mailing list archive)
State Superseded
Delegated to: Geert Uytterhoeven
Headers show

Commit Message

Masahiro Yamada Nov. 24, 2017, 4:24 p.m. UTC
A card detect GPIO is set up only for platforms with "cd-gpios"
DT property or TMIO_MMC_USE_GPIO_CD flag.  However, the driver
core always uses mmc_gpio_get_cd, which just fails with -ENOSYS
if ctx->cd_gpio is unset.

The bit 5 of the status register provides the current signal level
of the CD line.  Allow to use it if the GPIO is unused.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

Changes in v2: None

 drivers/mmc/host/tmio_mmc_core.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

Comments

Wolfram Sang Dec. 4, 2017, 3:13 p.m. UTC | #1
> +static int tmio_mmc_get_cd(struct mmc_host *mmc)
> +{
> +	struct tmio_mmc_host *host = mmc_priv(mmc);
> +	int ret;
> +
> +	ret = mmc_gpio_get_cd(mmc);
> +	if (ret >= 0)
> +		return ret;
> +
> +	return !!(sd_ctrl_read16_and_16_as_32(host, CTL_STATUS) &
> +							TMIO_STAT_SIGSTATE);
> +}

I wonder if we shouldn't do something like:

	if (mmc_can_gpio_cd())
		return mmc_gpio_get_cd()
	else
		return !!(sd_ctrl_read16_and_16_as_32...)

If we have a GPIO CD defined, I think we want the value of
mmc_gpio_get_cd() in all cases. It makes clearer that this is an
'either-or' case and not a fallback mechanism.
Masahiro Yamada Dec. 5, 2017, 3:03 p.m. UTC | #2
2017-12-05 0:13 GMT+09:00 Wolfram Sang <wsa@the-dreams.de>:
>> +static int tmio_mmc_get_cd(struct mmc_host *mmc)
>> +{
>> +     struct tmio_mmc_host *host = mmc_priv(mmc);
>> +     int ret;
>> +
>> +     ret = mmc_gpio_get_cd(mmc);
>> +     if (ret >= 0)
>> +             return ret;
>> +
>> +     return !!(sd_ctrl_read16_and_16_as_32(host, CTL_STATUS) &
>> +                                                     TMIO_STAT_SIGSTATE);
>> +}


I just followed tmio_mmc_get_ro() implementation.

If we do not care the symmetry between _get_ro() and _get_cd() hooks,
yes, your suggestion makes sense.



> I wonder if we shouldn't do something like:
>
>         if (mmc_can_gpio_cd())
>                 return mmc_gpio_get_cd()
>         else
>                 return !!(sd_ctrl_read16_and_16_as_32...)
>
> If we have a GPIO CD defined, I think we want the value of
> mmc_gpio_get_cd() in all cases. It makes clearer that this is an
> 'either-or' case and not a fallback mechanism.
>


Another possibility would select this in _probe().
We would need to evaluate mmc_can_gpio_cd() only once when probing.

I will follow your suggestion, though.
Either way is fine with me.



static int tmio_mmc_get_cd(struct mmc_host *mmc)
{
       struct tmio_mmc_host *host = mmc_priv(mmc);

       return !!(sd_ctrl_read16_and_16_as_32(host, CTL_STATUS) &
                                                TMIO_STAT_SIGSTATE);
}

static const struct mmc_host_ops tmio_mmc_ops = {
      ...
      .get_cd      = tmio_mmc_get_cd,
      ...
};

int tmio_mmc_host_probe( ... )
{
      ....

      /* replace get_cd hook when we use GPIO for card detection */
      if (mmc_can_gpio_cd(mmc))
                _host->ops.get_cd = mmc_gpio_get_cd;


}
Wolfram Sang Dec. 5, 2017, 3:28 p.m. UTC | #3
> Another possibility would select this in _probe().
> We would need to evaluate mmc_can_gpio_cd() only once when probing.

I like this, too.

Maybe like this to be more obvious:

	if (mmc_can_gpio_cd(mmc))
		 _host->ops.get_cd = mmc_gpio_get_cd;
	else
		 _host->ops.get_cd = tmio...

?
Wolfram Sang Jan. 2, 2018, 12:58 p.m. UTC | #4
On Sat, Nov 25, 2017 at 01:24:45AM +0900, Masahiro Yamada wrote:
> A card detect GPIO is set up only for platforms with "cd-gpios"
> DT property or TMIO_MMC_USE_GPIO_CD flag.  However, the driver
> core always uses mmc_gpio_get_cd, which just fails with -ENOSYS
> if ctx->cd_gpio is unset.
> 
> The bit 5 of the status register provides the current signal level
> of the CD line.  Allow to use it if the GPIO is unused.
> 
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

As mentioned before (sorry, I lost this thread :( ), I like the
refactoring to select in probe() which function to call depending on
GPIO usage or not. If you like, we can do the same for read_only, too.

Thanks!
diff mbox

Patch

diff --git a/drivers/mmc/host/tmio_mmc_core.c b/drivers/mmc/host/tmio_mmc_core.c
index 610f26f..b51bb06 100644
--- a/drivers/mmc/host/tmio_mmc_core.c
+++ b/drivers/mmc/host/tmio_mmc_core.c
@@ -1087,6 +1087,19 @@  static int tmio_mmc_get_ro(struct mmc_host *mmc)
 	return ret;
 }
 
+static int tmio_mmc_get_cd(struct mmc_host *mmc)
+{
+	struct tmio_mmc_host *host = mmc_priv(mmc);
+	int ret;
+
+	ret = mmc_gpio_get_cd(mmc);
+	if (ret >= 0)
+		return ret;
+
+	return !!(sd_ctrl_read16_and_16_as_32(host, CTL_STATUS) &
+							TMIO_STAT_SIGSTATE);
+}
+
 static int tmio_multi_io_quirk(struct mmc_card *card,
 			       unsigned int direction, int blk_size)
 {
@@ -1102,7 +1115,7 @@  static const struct mmc_host_ops tmio_mmc_ops = {
 	.request	= tmio_mmc_request,
 	.set_ios	= tmio_mmc_set_ios,
 	.get_ro         = tmio_mmc_get_ro,
-	.get_cd		= mmc_gpio_get_cd,
+	.get_cd		= tmio_mmc_get_cd,
 	.enable_sdio_irq = tmio_mmc_enable_sdio_irq,
 	.multi_io_quirk	= tmio_multi_io_quirk,
 	.hw_reset	= tmio_mmc_hw_reset,