2021-01-10 16:57:56

by Guido Günther

Subject: [PATCH v2] arm64: dts: imx8mq: Add clock parents for mipi dphy

This makes sure the clock tree setup for the dphy is not dependent on
other components.

Without this change bringing up the display can fail like

kernel: phy phy-30a00300.dphy.2: Invalid CM/CN/CO values: 165/217/1
kernel: phy phy-30a00300.dphy.2: for hs_clk/ref_clk=451656000/593999998 ~ 165/217

if LCDIF doesn't set up that part of the clock tree first. This was
noticed when testing the Librem 5 devkit with defconfig. It doesn't
happen when modules are built in.

Signed-off-by: Guido Günther <[email protected]>

---
Changes from v1:
- as per review comment from Shawn Guo
https://lore.kernel.org/linux-arm-kernel/20210110124629.GO28365@dragon/
Set clock rate for IMX8MQ_VIDEO_PLL1 too. Otherwise we end up with
a close but not exact clock rate.

arch/arm64/boot/dts/freescale/imx8mq.dtsi | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/boot/dts/freescale/imx8mq.dtsi b/arch/arm64/boot/dts/freescale/imx8mq.dtsi
index a841a023e8e0..50ae17f65a51 100644
--- a/arch/arm64/boot/dts/freescale/imx8mq.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mq.dtsi
@@ -1016,9 +1016,14 @@ dphy: dphy@30a00300 {
reg = <0x30a00300 0x100>;
clocks = <&clk IMX8MQ_CLK_DSI_PHY_REF>;
clock-names = "phy_ref";
- assigned-clocks = <&clk IMX8MQ_CLK_DSI_PHY_REF>;
- assigned-clock-parents = <&clk IMX8MQ_VIDEO_PLL1_OUT>;
- assigned-clock-rates = <24000000>;
+ assigned-clocks = <&clk IMX8MQ_VIDEO_PLL1_REF_SEL>,
+ <&clk IMX8MQ_VIDEO_PLL1_BYPASS>,
+ <&clk IMX8MQ_CLK_DSI_PHY_REF>,
+ <&clk IMX8MQ_VIDEO_PLL1>;
+ assigned-clock-parents = <&clk IMX8MQ_CLK_25M>,
+ <&clk IMX8MQ_VIDEO_PLL1>,
+ <&clk IMX8MQ_VIDEO_PLL1_OUT>;
+ assigned-clock-rates = <0>, <0>, <24000000>, <594000000>;
#phy-cells = <0>;
power-domains = <&pgc_mipi>;
status = "disabled";
--
2.29.2

2021-01-11 00:27:58

by Shawn Guo

Subject: Re: [PATCH v2] arm64: dts: imx8mq: Add clock parents for mipi dphy

On Sun, Jan 10, 2021 at 05:55:51PM +0100, Guido G?nther wrote:
> This makes sure the clock tree setup for the dphy is not dependent on
> other components.
>
> Without this change bringing up the display can fail like
>
> kernel: phy phy-30a00300.dphy.2: Invalid CM/CN/CO values: 165/217/1
> kernel: phy phy-30a00300.dphy.2: for hs_clk/ref_clk=451656000/593999998 ~ 165/217
>
> if LCDIF doesn't set up that part of the clock tree first. This was
> noticed when testing the Librem 5 devkit with defconfig. It doesn't
> happen when modules are built in.
>
> Signed-off-by: Guido G?nther <[email protected]>

Applied, thanks.