linux-kernel - [PATCH 1/1] mmc: core: don't override the CD GPIO level when "cd-inverted" is set

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Date:   Tue,  1 Jan 2019 20:44:14 +0100
From:   Martin Blumenstingl <martin.blumenstingl@...glemail.com>
To:     linus.walleij@...aro.org, linux-gpio@...r.kernel.org,
        linux-mmc@...r.kernel.org
Cc:     linux@...ck-us.net, bgolaszewski@...libre.com,
        ulf.hansson@...aro.org, linux-amlogic@...ts.infradead.org,
        linux-kernel@...r.kernel.org,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>
Subject: [PATCH 1/1] mmc: core: don't override the CD GPIO level when "cd-inverted" is set

Since commit 89a5e15bcba87d ("gpio/mmc/of: Respect polarity in the device
tree") gpiolib-of parses the "cd-gpios" property and flips the polarity
if "cd-inverted" is also set. This results in the "cd-inverted" property
being evaluated twice, which effectively makes it a no-op:
- first in drivers/gpio/gpiolib-of.c (of_xlate_and_get_gpiod_flags) when
  setting up the CD GPIO
- then again in drivers/mmc/core/slot-gpio.c (mmc_gpio_get_cd) when
  reading the CD GPIO value at runtime

On boards which are using device-tree with the "cd-inverted" property
being set any inserted card are not detected anymore. This is due to the
MMC core treating the CD GPIO with the wrong polarity.

Disable "override_cd_active_level" for the card detection GPIO which is
parsed using mmc_of_parse. This fixes SD card detection on the boards
which are currently using the "cd-inverted" device-tree property (tested
on Meson8b Odroid-C1 and Meson8b EC-100).

This does not remove the CD GPIO inversion logic from the MMC core
because there's at least one driver (sdhci-pci-core for Intel BayTrail
based boards) which still passes "override_cd_active_level = true" to
mmc_gpiod_request_cd(). Due to lack of hardware for testing this is left
untouched.
In the future the GPIO inversion logic for both, card and read-only
detection can be removed once no driver is using it anymore.

Fixes: 89a5e15bcba87d ("gpio/mmc/of: Respect polarity in the device tree")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@...glemail.com>
---
 drivers/mmc/core/host.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index f57f5de54206..cf58ccaf22d5 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -234,7 +234,7 @@ int mmc_of_parse(struct mmc_host *host)
 		if (device_property_read_bool(dev, "broken-cd"))
 			host->caps |= MMC_CAP_NEEDS_POLL;

-		ret = mmc_gpiod_request_cd(host, "cd", 0, true,
+		ret = mmc_gpiod_request_cd(host, "cd", 0, false,
 					   cd_debounce_delay_ms * 1000,
 					   &cd_gpio_invert);
 		if (!ret)
-- 
2.20.1