ARC: [plat-hsdk] sdio: Temporary fix of sdio ciu frequency

DW sdio controller has external ciu clock divider controlled via
register in SDIO IP. Due to its unexpected default value
(it should divide by 1 but it divides by 8)
SDIO IP uses wrong ciu clock and works unstable

So add temporary fix and change clock frequency from 100000000
to 12500000 Hz until we fix dw sdio driver itself.

Fixes SNPS STAR 9001204800

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

diff --git a/arch/arc/boot/dts/hsdk.dts b/arch/arc/boot/dts/hsdk.dts
index 229d13adbce426c1690684f7e8dcb344a001429d..daeef4ab2df91ec3ad9131013fa13ff259267b81 100644 (file)
--- a/arch/arc/boot/dts/hsdk.dts
+++ b/arch/arc/boot/dts/hsdk.dts
@@ -120,7 +120,17 @@
 
                mmcclk_ciu: mmcclk-ciu {
                        compatible = "fixed-clock";
-                       clock-frequency = <100000000>;
+                       /*
+                        * DW sdio controller has external ciu clock divider
+                        * controlled via register in SDIO IP. Due to its
+                        * unexpected default value (it should devide by 1
+                        * but it devides by 8) SDIO IP uses wrong clock and
+                        * works unstable (see STAR 9001204800)
+                        * So add temporary fix and change clock frequency
+                        * from 100000000 to 12500000 Hz until we fix dw sdio
+                        * driver itself.
+                        */
+                       clock-frequency = <12500000>;
                        #clock-cells = <0>;
                };