mmc: core: fix card detection regression

Since commit 89168b489915 ("mmc: core: restore detect line inversion
semantics"), the SD card on i.MX28 (and possibly other) devices isn't
detected and booting stops at:

[    4.120617] Waiting for root device /dev/mmcblk0p3...

This is caused by the MMC_CAP2_CD_ACTIVE_HIGH flag being set incorrectly
when the host controller doesn't use a GPIO for card detection (but
instead uses a dedicated pin). In this case mmc_gpiod_request_cd() will
return before assigning to the gpio_invert variable, leaving the
variable uninitialized. The variable then gets used to set the flag.
This patch fixes the issue by making sure gpio_invert is set to false
when a GPIO isn't used. After this patch, i.MX28 boots fine.

The MMC_CAP2_RO_ACTIVE_HIGH (write protect) flag is also set incorrectly
for the exact same reason (it uses the same uninitialized variable), so
this patch fixes that too.

Fixes: 89168b489915 ("mmc: core: restore detect line inversion semantics")
Reported-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Kristina Martšenko <kristina.martsenko@gmail.com>
Tested-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

1 files changed, 8 insertions, 13 deletions

diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index 03c53b72a2d6..270d58a4c43d 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -311,7 +311,8 @@ int mmc_of_parse(struct mmc_host *host)
         struct device_node *np;
         u32 bus_width;
         int len, ret;
-        bool cap_invert, gpio_invert;
+        bool cd_cap_invert, cd_gpio_invert = false;
+        bool ro_cap_invert, ro_gpio_invert = false;
 
         if (!host->parent || !host->parent->of_node)
                 return 0;
@@ -359,16 +360,13 @@ int mmc_of_parse(struct mmc_host *host)
         if (of_find_property(np, "non-removable", &len)) {
                 host->caps |= MMC_CAP_NONREMOVABLE;
         } else {
-                if (of_property_read_bool(np, "cd-inverted"))
-                        cap_invert = true;
-                else
-                        cap_invert = false;
+                cd_cap_invert = of_property_read_bool(np, "cd-inverted");
 
                 if (of_find_property(np, "broken-cd", &len))
                         host->caps |= MMC_CAP_NEEDS_POLL;
 
                 ret = mmc_gpiod_request_cd(host, "cd", 0, true,
-                                           0, &gpio_invert);
+                                           0, &cd_gpio_invert);
                 if (ret) {
                         if (ret == -EPROBE_DEFER)
                                 return ret;
@@ -391,17 +389,14 @@ int mmc_of_parse(struct mmc_host *host)
                  * both inverted, the end result is that the CD line is
                  * not inverted.
                  */
-                if (cap_invert ^ gpio_invert)
+                if (cd_cap_invert ^ cd_gpio_invert)
                         host->caps2 |= MMC_CAP2_CD_ACTIVE_HIGH;
         }
 
         /* Parse Write Protection */
-        if (of_property_read_bool(np, "wp-inverted"))
-                cap_invert = true;
-        else
-                cap_invert = false;
+        ro_cap_invert = of_property_read_bool(np, "wp-inverted");
 
-        ret = mmc_gpiod_request_ro(host, "wp", 0, false, 0, &gpio_invert);
+        ret = mmc_gpiod_request_ro(host, "wp", 0, false, 0, &ro_gpio_invert);
         if (ret) {
                 if (ret == -EPROBE_DEFER)
                         goto out;
@@ -414,7 +409,7 @@ int mmc_of_parse(struct mmc_host *host)
                 dev_info(host->parent, "Got WP GPIO\n");
 
         /* See the comment on CD inversion above */
-        if (cap_invert ^ gpio_invert)
+        if (ro_cap_invert ^ ro_gpio_invert)
                 host->caps2 |= MMC_CAP2_RO_ACTIVE_HIGH;
 
         if (of_find_property(np, "cap-sd-highspeed", &len))