Received-SPF: pass (google.com: domain of linux-kernel+bounces-60982-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249;
From: Adam Ford <aford173@gmail.com>
To: linux-arm-kernel@lists.infradead.org
Cc: marex@denx.de,
	aford@beaconembedded.com,
	Adam Ford <aford173@gmail.com>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>,
	NXP Linux Team <linux-imx@nxp.com>,
	devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH] arm64: dts: imx8mn: Slow default video_pll clock rate
Date: Sun, 11 Feb 2024 17:15:08 -0600
Message-ID: <20240211231508.188567-1-aford173@gmail.com>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

Since commit 8208181fe536 ("clk: imx: composite-8m:
Add imx8m_divider_determine_rate") the lcdif controller has
had the ability to set the disp_pixel_clk rate which propagates
up the tree and sets the video_pll rate automatically.

By setting this value low, it will force the recalculation of
video_pll to the lowest rate needed by lcdif instead of
dividing a larger clock down to the desired clock speed. This
has the  advantage of being able to lower the video_pll rate
from 594MHz to 148.5MHz when operating at 1080p. It can go even
lower when operating at lower resolutions and refresh rates.

Signed-off-by: Adam Ford <aford173@gmail.com>

diff --git a/arch/arm64/boot/dts/freescale/imx8mn.dtsi b/arch/arm64/boot/dts/freescale/imx8mn.dtsi
index 136e75c51251..932c8b05c75f 100644
--- a/arch/arm64/boot/dts/freescale/imx8mn.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mn.dtsi
@@ -1168,7 +1168,7 @@ disp_blk_ctrl: blk-ctrl@32e28000 {
 							 <&clk IMX8MN_SYS_PLL1_800M>;
 				assigned-clock-rates = <266000000>,
 						       <24000000>,
-						       <594000000>,
+						       <24000000>,
 						       <500000000>,
 						       <200000000>;
 				#power-domain-cells = <1>;
-- 
2.43.0