mmc: Add support for Qualcomm SDHCI controller

Add support for SD/eMMC controller present on some Qualcomm Snapdragon
devices. This controller implements SDHCI 2.0 interface but requires
vendor-specific initialization.
Driver works in PIO mode as ADMA is not supported by U-Boot (yet).

Signed-off-by: Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/doc/device-tree-bindings/mmc/msm_sdhci.txt b/doc/device-tree-bindings/mmc/msm_sdhci.txt
new file mode 100644
index 0000000..08a290c
--- /dev/null
+++ b/doc/device-tree-bindings/mmc/msm_sdhci.txt
@@ -0,0 +1,25 @@
+Qualcomm Snapdragon SDHCI controller
+
+Required properties:
+- compatible : "qcom,sdhci-msm-v4"
+- reg: Base address and length of registers:
+	- Host controller registers (SDHCI)
+	- SD Core registers
+- clock: interface clock (must accept SD bus clock as a frequency)
+
+Optional properties:
+- index: If there is more than one controller - controller index (required
+	by generic SDHCI code).
+- bus_width: Width of SD/eMMC bus (default 4)
+- clock-frequency: Frequency of SD/eMMC bus (default 400 kHz)
+
+Example:
+
+sdhci@07864000 {
+	compatible = "qcom,sdhci-msm-v4";
+	reg = <0x7864900 0x11c 0x7864000 0x800>;
+	index = <0x1>;
+	bus-width = <0x4>;
+	clock = <&clkc 1>;
+	clock-frequency = <200000000>;
+};