Re: [PATCH] arm64: dts: imx8mp: Clarify csis clock frequency
From: Alexander Stein <hidden>
Date: 2024-08-15 12:12:16
Also in:
imx, linux-devicetree, linux-media
Hi Laurent, thanks for the patch. Am Mittwoch, 14. August 2024, 01:40:10 CEST schrieb Laurent Pinchart:
quoted hunk ↗ jump to hunk
The DT nodes for the MIPI CSI-2 receivers (MIPI_CSI) configure the CAM1_PIX and CAM2_PIX clocks to 266 MHz through the assigned-clock-rates property, and report that frequency in the clock-frequency property. The i.MX8MP reference manual and datasheet list 266 MHz as a nominal frequency when using both CSI-2 receivers, so all looks normal. In reality, the clock is actually set to 250 MHz, as the selected parent, IMX8MP_SYS_PLL2_1000M, has a 1/4 output that is selected as the closest frequency to 266 MHz. This doesn't break operation of the device, but is clearly misleading. Clarify the clock configuration by selecting the IMX8MP_SYS_PLL2_250M parent, dropping the redundant assigned-clock-rates, and setting clock-frequency to 250 MHz. This doesn't cause any functional change. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> --- arch/arm64/boot/dts/freescale/imx8mp.dtsi | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-)diff --git a/arch/arm64/boot/dts/freescale/imx8mp.dtsi b/arch/arm64/boot/dts/freescale/imx8mp.dtsi index 603dfe80216f..d9b5c40f6460 100644 --- a/arch/arm64/boot/dts/freescale/imx8mp.dtsi +++ b/arch/arm64/boot/dts/freescale/imx8mp.dtsi@@ -1687,7 +1687,7 @@ mipi_csi_0: csi@32e40000 { compatible = "fsl,imx8mp-mipi-csi2", "fsl,imx8mm-mipi-csi2"; reg = <0x32e40000 0x10000>; interrupts = <GIC_SPI 17 IRQ_TYPE_LEVEL_HIGH>; - clock-frequency = <266000000>; + clock-frequency = <250000000>;
This doesn't seem to be necessary, no? I can't be read from IMX8MP_CLK_MEDIA_CAM1_PIX_ROOT. But oh well, that's what we have right now. Despite that: Reviewed-by: Alexander Stein <redacted> Tested-by: Alexander Stein <redacted>
quoted hunk ↗ jump to hunk
clocks = <&clk IMX8MP_CLK_MEDIA_APB_ROOT>, <&clk IMX8MP_CLK_MEDIA_CAM1_PIX_ROOT>, <&clk IMX8MP_CLK_MEDIA_MIPI_PHY1_REF_ROOT>,@@ -1695,9 +1695,8 @@ mipi_csi_0: csi@32e40000 { clock-names = "pclk", "wrap", "phy", "axi"; assigned-clocks = <&clk IMX8MP_CLK_MEDIA_CAM1_PIX>, <&clk IMX8MP_CLK_MEDIA_MIPI_PHY1_REF>; - assigned-clock-parents = <&clk IMX8MP_SYS_PLL2_1000M>, + assigned-clock-parents = <&clk IMX8MP_SYS_PLL2_250M>, <&clk IMX8MP_CLK_24M>; - assigned-clock-rates = <266000000>; power-domains = <&media_blk_ctrl IMX8MP_MEDIABLK_PD_MIPI_CSI2_1>; status = "disabled";@@ -1723,7 +1722,7 @@ mipi_csi_1: csi@32e50000 { compatible = "fsl,imx8mp-mipi-csi2", "fsl,imx8mm-mipi-csi2"; reg = <0x32e50000 0x10000>; interrupts = <GIC_SPI 80 IRQ_TYPE_LEVEL_HIGH>; - clock-frequency = <266000000>; + clock-frequency = <250000000>; clocks = <&clk IMX8MP_CLK_MEDIA_APB_ROOT>, <&clk IMX8MP_CLK_MEDIA_CAM2_PIX_ROOT>, <&clk IMX8MP_CLK_MEDIA_MIPI_PHY1_REF_ROOT>,@@ -1731,9 +1730,8 @@ mipi_csi_1: csi@32e50000 { clock-names = "pclk", "wrap", "phy", "axi"; assigned-clocks = <&clk IMX8MP_CLK_MEDIA_CAM2_PIX>, <&clk IMX8MP_CLK_MEDIA_MIPI_PHY1_REF>; - assigned-clock-parents = <&clk IMX8MP_SYS_PLL2_1000M>, + assigned-clock-parents = <&clk IMX8MP_SYS_PLL2_250M>, <&clk IMX8MP_CLK_24M>; - assigned-clock-rates = <266000000>; power-domains = <&media_blk_ctrl IMX8MP_MEDIABLK_PD_MIPI_CSI2_2>; status = "disabled";base-commit: 7c626ce4bae1ac14f60076d00eafe71af30450ba
-- TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany Amtsgericht München, HRB 105018 Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider http://www.tq-group.com/