ARC: [plat-axs10x] sdio: Temporary fix of sdio ciu frequency

Eugeniy Paltsev · vineetgarc · commit 976e78a52265 · 2017-10-03T20:36:49.000-07:00
DW sdio controller has external ciu clock divider controlled via register in SDIO IP. It divides sdio_ref_clk (which comes from CGU) by 16 for default. So default mmcclk clock (which comes to sdk_in) is 25000000 Hz. So fix wrong current value (50000000 Hz) to actual 25000000 Hz. Note this is a preventive fix, in line with similar change for HSDK where this was actually needed. see: http://lists.infradead.org/pipermail/linux-snps-arc/2017-September/002924.html Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
diff --git a/arch/arc/boot/dts/axs10x_mb.dtsi b/arch/arc/boot/dts/axs10x_mb.dtsi
@@ -44,7 +44,14 @@
 
 			mmcclk: mmcclk {
 				compatible = "fixed-clock";
-				clock-frequency = <50000000>;
+				/*
+				 * DW sdio controller has external ciu clock divider
+				 * controlled via register in SDIO IP. It divides
+				 * sdio_ref_clk (which comes from CGU) by 16 for
+				 * default. So default mmcclk clock (which comes
+				 * to sdk_in) is 25000000 Hz.
+				 */
+				clock-frequency = <25000000>;
 				#clock-cells = <0>;
 			};
 
