mmc: core: Add DT bindings for eMMC high-speed DDR 1.8/1.2V

Provide the option to configure these speed modes per host, for those
host driver's that can't distinguish this in runtime.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Chris Ball <chris@printf.net>

Documentation/devicetree/bindings/mmc/mmc.txt

@@ -34,6 +34,8 @@ Optional properties:
 - cap-power-off-card: powering off the card is safe
 - cap-sdio-irq: enable SDIO IRQ signalling on this interface
 - full-pwr-cycle: full power cycle of the card is supported
+- mmc-highspeed-ddr-1_8v: eMMC high-speed DDR mode(1.8V I/O) is supported
+- mmc-highspeed-ddr-1_2v: eMMC high-speed DDR mode(1.2V I/O) is supported
 
 *NOTE* on CD and WP polarity. To use common for all SD/MMC host controllers line
 polarity properties, we have to fix the meaning of the "normal" and "inverted"

drivers/mmc/core/host.c

@@ -439,6 +439,10 @@ int mmc_of_parse(struct mmc_host *host)
 		host->pm_caps |= MMC_PM_KEEP_POWER;
 	if (of_find_property(np, "enable-sdio-wakeup", &len))
 		host->pm_caps |= MMC_PM_WAKE_SDIO_IRQ;
+	if (of_find_property(np, "mmc-ddr-1_8v", &len))
+		host->caps |= MMC_CAP_1_8V_DDR;
+	if (of_find_property(np, "mmc-ddr-1_2v", &len))
+		host->caps |= MMC_CAP_1_2V_DDR;
 
 	return 0;