ARM: shmobile: koelsch: add Volume Ramp usage on comment

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

diff --git a/arch/arm/boot/dts/r8a7791-koelsch.dts b/arch/arm/boot/dts/r8a7791-koelsch.dts
index a10f534ecec7279f265183bf0f9f35bdf64fa537..487fc99a2fa3919dab3cd15ee6d50dcf90725bab 100644 (file)
--- a/arch/arm/boot/dts/r8a7791-koelsch.dts
+++ b/arch/arm/boot/dts/r8a7791-koelsch.dts
@@ -27,6 +27,15 @@
  *
  *     amixer set "DVC Out Mute" on
  *     amixer set "DVC In Mute" on
+ *
+ * You can use Volume Ramp
+ *
+ *     amixer set "DVC Out Ramp Up Rate"   "0.125 dB/64 steps"
+ *     amixer set "DVC Out Ramp Down Rate" "0.125 dB/512 steps"
+ *     amixer set "DVC Out Ramp" on
+ *     aplay xxx.wav &
+ *     amixer set "DVC Out"  80%  // Volume Down
+ *     amixer set "DVC Out" 100%  // Volume Up
  */
 
 /dts-v1/;