[PATCH] arm64: dts: imx8mp: Fix TC9595 input clock on DH i.MX8M Plus DHCOM SoM

[PATCH] arm64: dts: imx8mp: Fix TC9595 input clock on DH i.MX8M Plus DHCOM SoM

[Marek Vasut]

The IMX8MP_CLK_CLKOUT2 supplies the TC9595 bridge with 13 MHz reference
clock. The IMX8MP_CLK_CLKOUT2 is supplied from IMX8MP_AUDIO_PLL2_OUT.
The IMX8MP_CLK_CLKOUT2 operates only as a power-of-two divider, and the
current 156 MHz is not power-of-two divisible to achieve 13 MHz.

To achieve 13 MHz output from IMX8MP_CLK_CLKOUT2, set IMX8MP_AUDIO_PLL2_OUT
to 208 MHz, because 208 MHz / 16 = 13 MHz.

Fixes: 20d0b83e712b ("arm64: dts: imx8mp: Add TC9595 bridge on DH electronics i.MX8M Plus DHCOM")
Signed-off-by: Marek Vasut <marex@denx.de>
---
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: devicetree@vger.kernel.org
Cc: imx@lists.linux.dev
Cc: kernel@dh-electronics.com
Cc: linux-arm-kernel@lists.infradead.org
---
 arch/arm64/boot/dts/freescale/imx8mp-dhcom-som.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/freescale/imx8mp-dhcom-som.dtsi b/arch/arm64/boot/dts/freescale/imx8mp-dhcom-som.dtsi
index 882186d96f58b..4d30f74622a18 100644
--- a/arch/arm64/boot/dts/freescale/imx8mp-dhcom-som.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mp-dhcom-som.dtsi
@@ -254,7 +254,7 @@ tc_bridge: bridge@f {
 				  <&clk IMX8MP_CLK_CLKOUT2>,
 				  <&clk IMX8MP_AUDIO_PLL2_OUT>;
 		assigned-clock-parents = <&clk IMX8MP_AUDIO_PLL2_OUT>;
-		assigned-clock-rates = <13000000>, <13000000>, <156000000>;
+		assigned-clock-rates = <13000000>, <13000000>, <208000000>;
 		reset-gpios = <&gpio4 1 GPIO_ACTIVE_HIGH>;
 		status = "okay";
 
-- 
2.43.0

Re: [PATCH] arm64: dts: imx8mp: Fix TC9595 input clock on DH i.MX8M Plus DHCOM SoM

[Shawn Guo]

On Mon, May 13, 2024 at 04:04:39AM +0200, Marek Vasut wrote:
> The IMX8MP_CLK_CLKOUT2 supplies the TC9595 bridge with 13 MHz reference
> clock. The IMX8MP_CLK_CLKOUT2 is supplied from IMX8MP_AUDIO_PLL2_OUT.
> The IMX8MP_CLK_CLKOUT2 operates only as a power-of-two divider, and the
> current 156 MHz is not power-of-two divisible to achieve 13 MHz.
> 
> To achieve 13 MHz output from IMX8MP_CLK_CLKOUT2, set IMX8MP_AUDIO_PLL2_OUT
> to 208 MHz, because 208 MHz / 16 = 13 MHz.
> 
> Fixes: 20d0b83e712b ("arm64: dts: imx8mp: Add TC9595 bridge on DH electronics i.MX8M Plus DHCOM")
> Signed-off-by: Marek Vasut <marex@denx.de>

Applied, thanks!