On 6/11/24 3:04 AM, Peng Fan wrote:
Subject: Re: [PATCH v2] arm64: dts: imx8mp: Add DT nodes for the two ISPs
Something like
---8<---
--- a/arch/arm64/boot/dts/freescale/imx8mp.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mp.dtsi
@@ -1837,11 +1837,13 @@ media_blk_ctrl: blk-ctrl@32ec0000 {
<&clk IMX8MP_CLK_MEDIA_APB>,
<&clk IMX8MP_CLK_MEDIA_DISP1_PIX>,
<&clk
IMX8MP_CLK_MEDIA_DISP2_PIX>,
+ <&clk
+ IMX8MP_CLK_MEDIA_ISP>,
<&clk IMX8MP_VIDEO_PLL1>;
assigned-clock-parents = <&clk
IMX8MP_SYS_PLL2_1000M>,
<&clk IMX8MP_SYS_PLL1_800M>,
<&clk IMX8MP_VIDEO_PLL1_OUT>,
- <&clk IMX8MP_VIDEO_PLL1_OUT>;
+ <&clk IMX8MP_VIDEO_PLL1_OUT>,
+ <&clk
+ IMX8MP_SYS_PLL2_500M>;
assigned-clock-rates = <500000000>, <200000000>,
<0>, <0>,
<1039500000>;
According to the i.MX8MP Data sheet, the nominal speed for
MEDIA_ISP_CLOCL_ROOT is 400MHZ with 500MHz being allowed in
overdrive mode.
I think this clock rate should drop to the nominal value of 400MHz and those
boards who support overdrive can increase it to 500MHz to avoid stiability
issues and/or running out of spec. I created an imx8mm and imx8mn-
overdrive.dtsi file. If there is interest, I can do the same for the 8MP as well.
I haven't gone through all the clocks to determine if/what clocks are being
overdriven.
Shouldn't the bootloader take the work to runtime update the freq?
Why need introduce an extra overdrive.dtsi?
Shouldn't the overdrive/non-overdrive decision be done in board DT instead ?
