mmc: sdhci: query card presence from cd-gpio before asking SDHCI

Call mmc_gpio_get_cd() to query card presence from cd-gpio before
asking SDHCI.  The rationale behind this change is that flag
SDHCI_QUIRK_BROKEN_CARD_DETECTION is designed for SDHCI controller to
tell that SDHCI_PRESENT_STATE is broken, and it should be used for this
case only.  So when cd-gpio is being used, the controller should set
the flag to tell that SDHCI_PRESENT_STATE is not available.

However, the existing code will skip checking cd-gpio as long as flag
SDHCI_QUIRK_BROKEN_CARD_DETECTION is set.  Change the querying order
between cd-gpio and SDHCI to support the rationale above.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 6f0bfc0..1b97fe2 100644 (file)
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1258,7 +1258,7 @@ static int sdhci_set_power(struct sdhci_host *host, unsigned short power)
 static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
 {
        struct sdhci_host *host;
-       bool present;
+       int present;
        unsigned long flags;
        u32 tuning_opcode;
 
@@ -1287,18 +1287,21 @@ static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
 
        host->mrq = mrq;
 
-       /* If polling, assume that the card is always present. */
-       if (host->quirks & SDHCI_QUIRK_BROKEN_CARD_DETECTION)
-               present = true;
-       else
-               present = sdhci_readl(host, SDHCI_PRESENT_STATE) &
-                               SDHCI_CARD_PRESENT;
-
-       /* If we're using a cd-gpio, testing the presence bit might fail. */
-       if (!present) {
-               int ret = mmc_gpio_get_cd(host->mmc);
-               if (ret > 0)
-                       present = true;
+       /*
+        * Firstly check card presence from cd-gpio.  The return could
+        * be one of the following possibilities:
+        *     negative: cd-gpio is not available
+        *     zero: cd-gpio is used, and card is removed
+        *     one: cd-gpio is used, and card is present
+        */
+       present = mmc_gpio_get_cd(host->mmc);
+       if (present < 0) {
+               /* If polling, assume that the card is always present. */
+               if (host->quirks & SDHCI_QUIRK_BROKEN_CARD_DETECTION)
+                       present = 1;
+               else
+                       present = sdhci_readl(host, SDHCI_PRESENT_STATE) &
+                                       SDHCI_CARD_PRESENT;
        }
 
        if (!present || host->flags & SDHCI_DEVICE_DEAD) {