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

Message ID 1511540697-27387-11-git-send-email-yamada.masahiro@socionext.com
State New
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Series
  • Untitled series #6361
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Commit Message

Masahiro Yamada Nov. 24, 2017, 4:24 p.m.
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(-)

-- 
2.7.4

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Comments

Masahiro Yamada Dec. 5, 2017, 3:03 p.m. | #1
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;


}





-- 
Best Regards
Masahiro Yamada
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Wolfram Sang Dec. 5, 2017, 3:28 p.m. | #2
> 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...

?

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,