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>

diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index 03c53b72a2d6a34bafbea7e1a1bda90299772fa8..270d58a4c43dd0e25ffa66718ca0c0ada9ad5036 100644 (file)
--- 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))