mmc: sdhci: Add quirk to disable LED control

Host controllers may not have a LED signal line, whereas the register
updates to control the non-existent LED can be relatively time consuming.
Add a quirk to disable LED control.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci.c

@@ -349,6 +349,9 @@ static void __sdhci_led_activate(struct sdhci_host *host)
 {
 	u8 ctrl;
 
+	if (host->quirks & SDHCI_QUIRK_NO_LED)
+		return;
+
 	ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
 	ctrl |= SDHCI_CTRL_LED;
 	sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
@@ -358,6 +361,9 @@ static void __sdhci_led_deactivate(struct sdhci_host *host)
 {
 	u8 ctrl;
 
+	if (host->quirks & SDHCI_QUIRK_NO_LED)
+		return;
+
 	ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
 	ctrl &= ~SDHCI_CTRL_LED;
 	sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
@@ -387,6 +393,9 @@ static int sdhci_led_register(struct sdhci_host *host)
 {
 	struct mmc_host *mmc = host->mmc;
 
+	if (host->quirks & SDHCI_QUIRK_NO_LED)
+		return 0;
+
 	snprintf(host->led_name, sizeof(host->led_name),
 		 "%s::", mmc_hostname(mmc));
 
@@ -400,6 +409,9 @@ static int sdhci_led_register(struct sdhci_host *host)
 
 static void sdhci_led_unregister(struct sdhci_host *host)
 {
+	if (host->quirks & SDHCI_QUIRK_NO_LED)
+		return;
+
 	led_classdev_unregister(&host->led);
 }
 

drivers/mmc/host/sdhci.h

@@ -408,6 +408,8 @@ struct sdhci_host {
 #define SDHCI_QUIRK_INVERTED_WRITE_PROTECT		(1<<16)
 /* Controller does not like fast PIO transfers */
 #define SDHCI_QUIRK_PIO_NEEDS_DELAY			(1<<18)
+/* Controller does not have a LED */
+#define SDHCI_QUIRK_NO_LED				(1<<19)
 /* Controller has to be forced to use block size of 2048 bytes */
 #define SDHCI_QUIRK_FORCE_BLK_SZ_2048			(1<<20)
 /* Controller cannot do multi-block transfers */