[PATCH v1] arm64: dts: imx8-apalis: add clock configuration for 44.1 kHz hdmi audio

[PATCH v1] arm64: dts: imx8-apalis: add clock configuration for 44.1 kHz hdmi audio

[Stefan Eichenberger]

From: Stefan Eichenberger <stefan.eichenberger@toradex.com>

Currently, HDMI audio cannot play sound at a 44.1 kHz sample rate due to
a clock frequency mismatch. This update resolves the issue by allowing
the sai driver to change the clock parent to AUDIO_PLL_1 when the sample
rate is 44.1 kHz. It also ensures that AUDIO_PLL_1 operates at the
correct frequency for this configuration.

Signed-off-by: Stefan Eichenberger <stefan.eichenberger@toradex.com>
---
This patch is based on the following discussion:
https://lore.kernel.org/all/20250113094654.12998-1-eichest@gmail.com/
We use the existing mechanisms and just add the missing clock
configuration to our device tree.

 .../boot/dts/freescale/imx8-apalis-v1.1.dtsi     | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/imx8-apalis-v1.1.dtsi b/arch/arm64/boot/dts/freescale/imx8-apalis-v1.1.dtsi
index a3fc945aea16..dbea1eefdeec 100644
--- a/arch/arm64/boot/dts/freescale/imx8-apalis-v1.1.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8-apalis-v1.1.dtsi
@@ -790,6 +790,22 @@ &sai1 {
 	status = "okay";
 };
 
+/* Apalis HDMI Audio */
+&sai5 {
+	assigned-clocks = <&acm IMX_ADMA_ACM_SAI5_MCLK_SEL>,
+			  <&acm IMX_ADMA_ACM_AUD_CLK1_SEL>,
+			  <&clk IMX_SC_R_AUDIO_PLL_0 IMX_SC_PM_CLK_PLL>,
+			  <&clk IMX_SC_R_AUDIO_PLL_0 IMX_SC_PM_CLK_SLV_BUS>,
+			  <&clk IMX_SC_R_AUDIO_PLL_0 IMX_SC_PM_CLK_MST_BUS>,
+			  <&clk IMX_SC_R_AUDIO_PLL_1 IMX_SC_PM_CLK_PLL>,
+			  <&clk IMX_SC_R_AUDIO_PLL_1 IMX_SC_PM_CLK_SLV_BUS>,
+			  <&clk IMX_SC_R_AUDIO_PLL_1 IMX_SC_PM_CLK_MST_BUS>,
+			  <&sai5_lpcg 0>;
+	assigned-clock-parents = <&aud_pll_div0_lpcg 0>, <&aud_rec1_lpcg 0>;
+	assigned-clock-rates = <0>, <0>, <786432000>, <49152000>, <12288000>,
+			       <722534400>, <45158400>, <11289600>, <49152000>;
+};
+
 /* TODO: Apalis SATA1 */
 
 /* Apalis SPDIF1 */
-- 
2.45.2

Re: [PATCH v1] arm64: dts: imx8-apalis: add clock configuration for 44.1 kHz hdmi audio

[Shawn Guo]

On Mon, Jan 20, 2025 at 10:45:22AM +0100, Stefan Eichenberger wrote:
> From: Stefan Eichenberger <stefan.eichenberger@toradex.com>
> 
> Currently, HDMI audio cannot play sound at a 44.1 kHz sample rate due to
> a clock frequency mismatch. This update resolves the issue by allowing
> the sai driver to change the clock parent to AUDIO_PLL_1 when the sample
> rate is 44.1 kHz. It also ensures that AUDIO_PLL_1 operates at the
> correct frequency for this configuration.
> 
> Signed-off-by: Stefan Eichenberger <stefan.eichenberger@toradex.com>

Applied, thanks!