[PATCH v3 2/3] arm64: dts: rk3399: i2s: switch BCLK to GPIO

[Judy Hsiao]

We discovered that the state of BCLK on, LRCLK off and SD_MODE on
may cause the speaker melting issue. Removing LRCLK while BCLK
is present can cause unexpected output behavior including a large
DC output voltage as described in the Max98357a datasheet.

In order to:
  1. prevent BCLK from turning on by other component.
  2. keep BCLK and LRCLK being present at the same time

This patch adjusts the device tree to allow BCLK to switch
to GPIO func before LRCLK output, and switch back during
LRCLK is output.

Signed-off-by: Judy Hsiao <judyhsiao at chromium.org>
Reviewed-by: Brian Norris <briannorris at chromium.org>
---
 .../boot/dts/rockchip/rk3399-gru-scarlet.dtsi | 10 ++++++++
 arch/arm64/boot/dts/rockchip/rk3399.dtsi      | 25 ++++++++++++++++++-
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/rockchip/rk3399-gru-scarlet.dtsi b/arch/arm64/boot/dts/rockchip/rk3399-gru-scarlet.dtsi
index 913d845eb51a..df1647e9d487 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399-gru-scarlet.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3399-gru-scarlet.dtsi
@@ -766,6 +766,16 @@ &i2s0_8ch_bus {
 		<4 RK_PA0 1 &pcfg_pull_none_6ma>;
 };
 
+&i2s0_8ch_bus_bclk_off {
+	rockchip,pins =
+		<3 RK_PD0 RK_FUNC_GPIO &pcfg_pull_none_6ma>,
+		<3 RK_PD1 1 &pcfg_pull_none_6ma>,
+		<3 RK_PD2 1 &pcfg_pull_none_6ma>,
+		<3 RK_PD3 1 &pcfg_pull_none_6ma>,
+		<3 RK_PD7 1 &pcfg_pull_none_6ma>,
+		<4 RK_PA0 1 &pcfg_pull_none_6ma>;
+};
+
 /* there is no external pull up, so need to set this pin pull up */
 &sdmmc_cd_pin {
 	rockchip,pins = <1 RK_PB3 RK_FUNC_GPIO &pcfg_pull_up>;
diff --git a/arch/arm64/boot/dts/rockchip/rk3399.dtsi b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
index fbd0346624e6..311c8394cc84 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
@@ -1662,8 +1662,9 @@ i2s0: i2s at ff880000 {
 		dma-names = "tx", "rx";
 		clock-names = "i2s_clk", "i2s_hclk";
 		clocks = <&cru SCLK_I2S0_8CH>, <&cru HCLK_I2S0_8CH>;
-		pinctrl-names = "default";
+		pinctrl-names = "bclk_on", "bclk_off";
 		pinctrl-0 = <&i2s0_8ch_bus>;
+		pinctrl-1 = <&i2s0_8ch_bus_bclk_off>;
 		power-domains = <&power RK3399_PD_SDIOAUDIO>;
 		#sound-dai-cells = <0>;
 		status = "disabled";
@@ -2407,6 +2408,19 @@ i2s0_8ch_bus: i2s0-8ch-bus {
 					<3 RK_PD7 1 &pcfg_pull_none>,
 					<4 RK_PA0 1 &pcfg_pull_none>;
 			};
+
+			i2s0_8ch_bus_bclk_off: i2s0-8ch-bus-bclk-off {
+				rockchip,pins =
+					<3 RK_PD0 RK_FUNC_GPIO &pcfg_pull_none>,
+					<3 RK_PD1 1 &pcfg_pull_none>,
+					<3 RK_PD2 1 &pcfg_pull_none>,
+					<3 RK_PD3 1 &pcfg_pull_none>,
+					<3 RK_PD4 1 &pcfg_pull_none>,
+					<3 RK_PD5 1 &pcfg_pull_none>,
+					<3 RK_PD6 1 &pcfg_pull_none>,
+					<3 RK_PD7 1 &pcfg_pull_none>,
+					<4 RK_PA0 1 &pcfg_pull_none>;
+			};
 		};
 
 		i2s1 {
@@ -2418,6 +2432,15 @@ i2s1_2ch_bus: i2s1-2ch-bus {
 					<4 RK_PA6 1 &pcfg_pull_none>,
 					<4 RK_PA7 1 &pcfg_pull_none>;
 			};
+
+			i2s1_2ch_bus_bclk_off: i2s1-2ch-bus-bclk-off {
+				rockchip,pins =
+					<4 RK_PA3 RK_FUNC_GPIO &pcfg_pull_none>,
+					<4 RK_PA4 1 &pcfg_pull_none>,
+					<4 RK_PA5 1 &pcfg_pull_none>,
+					<4 RK_PA6 1 &pcfg_pull_none>,
+					<4 RK_PA7 1 &pcfg_pull_none>;
+			};
 		};
 
 		sdio0 {
-- 
2.36.1.476.g0c4daa206d-goog