fsl,imx8qxp-pwm lsio_pwm0-7 device tree nodes

[petero5]

Hi

imx8-ss-dma.dtsi has e.g. adma_pwm_lpcg *and* adma_pwm
but imx8-ss-lsio.dtsi has only e.g. pwm3_lpcg, not lsio_pwm3 (or similar)?

Found this similar question:
https://community.nxp.com/t5/i-MX-Processors/Enable-IMX8QXP-LSIO-PWM/m-p/966483/
but the solution references things that are no longer in lf-5.15.y

So based on that, and adma_pwm, have cobbled together the following. Seems to work. But just incase, are there any mistakes in it?

lsio_pwm3: pwm@5d030000 {
compatible = "fsl,imx8qxp-pwm", "fsl,imx27-pwm";
reg = <0x0 0x5d030000 0 0x1000>;
clocks = <&pwm3_lpcg 0>, <&pwm3_lpcg 1>;
clock-names = "ipg", "per";
assigned-clocks = <&clk IMX_SC_R_PWM_3 IMX_SC_PM_CLK_PER>;
assigned-clock-rates = <24000000>;
#pwm-cells = <2>;
power-domains = <&pd IMX_SC_R_PWM_3>;

pinctrl-names = "default";
pinctrl-0 = <&pinctrl_lsio_pwm3>;
status = "okay";
};

pinctrl_lsio_pwm3: lsio_pwm3_grp {
fsl,pins = <
IMX8QXP_UART1_CTS_B_LSIO_PWM3_OUT 0xC8000020
>;
};

Thank you
-- Peter

[AldoG]

Hello,

Yes, it looks correct if it is working then even better.

Just to make sure that you have the correct reference you may refer to the following:
https://github.com/nxp-imx/linux-imx/blob/lf-5.15.y/arch/arm64/boot/dts/freescale/imx8qxp-ss-lvds.dt...

Best regards,
Aldo.

[petero5]

Hi Aldo

Thank you. Question:

adma_pwm/adma_pwm_lpcg has two clocks: "per" and "ipg".

https://github.com/nxp-imx/linux-imx/blob/lf-5.15.y/arch/arm64/boot/dts/freescale/imx8-ss-dma.dtsi#L...

pwm_mipi_lvds0/mipi0_pwm_lpcg has "per", "ipg", "32k"

https://github.com/nxp-imx/linux-imx/blob/lf-5.15.y/arch/arm64/boot/dts/freescale/imx8qxp-ss-lvds.dt...

pwm3_lpcg has 5 clocks...

https://github.com/nxp-imx/linux-imx/blob/lf-5.15.y/arch/arm64/boot/dts/freescale/imx8-ss-lsio.dtsi#...

clocks = <&clk IMX_SC_R_PWM_3 IMX_SC_PM_CLK_PER>,
<&clk IMX_SC_R_PWM_3 IMX_SC_PM_CLK_PER>,
<&clk IMX_SC_R_PWM_3 IMX_SC_PM_CLK_PER>,
<&lsio_bus_clk>,
<&clk IMX_SC_R_PWM_3 IMX_SC_PM_CLK_PER>;

clock-output-names = "pwm3_lpcg_ipg_clk",
"pwm3_lpcg_ipg_hf_clk",
"pwm3_lpcg_ipg_s_clk",
"pwm3_lpcg_ipg_slv_clk",
"pwm3_lpcg_ipg_mstr_clk";

Well four of the five are the same, but the fourth entry is different (&lsio_bus_clk).

Should I be using all 5, and if so should I be using those names, or shorter names?

Or ...?

Thank you

-- Peter

[AldoG]

Hello,

Yes, please use them and do use the same macro names since they are called from the clock driver with this macro names.

Best regards,
Aldo.

[petero5]

Hi Aldo

Thank you, however I'm still not clear.
The driver pwm-imx27.c expects "ipg", "per" and optionally "32k".
https://github.com/nxp-imx/linux-imx/blob/lf-5.15.y/drivers/pwm/pwm-imx27.c#L385

However, pwm3_lpcg has five clocks
https://github.com/nxp-imx/linux-imx/blob/lf-5.15.y/arch/arm64/boot/dts/freescale/imx8-ss-lsio.dtsi#...
that it calls
"pwm3_lpcg_ipg_clk", "pwm3_lpcg_ipg_hf_clk", "pwm3_lpcg_ipg_s_clk", "pwm3_lpcg_ipg_slv_clk", "pwm3_lpcg_ipg_mstr_clk";

If I use those same long names in my node
lsio_pwm3: pwm@5d030000 {
compatible = "fsl,imx8qxp-pwm", "fsl,imx27-pwm";
...
then I get:
[ 2.718368] pwm-imx27 5d030000.pwm: error -ENOENT: getting ipg clock failed

And if I change mine to use short versions of those names e.g.
clock-names = "ipg", "hf", "s", "slv", "mstr";
then I get:
[ 2.711906] pwm-imx27 5d030000.pwm: error -ENOENT: failed to get peripheral clock

So if I'm using compatible "fsl,imx27-pwm", then I can only use the names "ipg", "per" and optionally "32k".
I guess "ipg" relates to clocks = <&pwm3_lpcg 0> but not sure which of the five "per" and "32k" would relate to?
Is compatible = "fsl,imx8qxp-pwm", "fsl,imx27-pwm"; correct or should I be using a different pwm driver that is expecting five clocks rather than three?

Thank you
-- Peter

[AldoG · Accepted solution]

Hello,

I made a mistake on your last post, sorry about that, no you shouldn't use the 5 listed there you may use only 2 of them and also yes you may use the definition of it for a shorter name, as you did in your first post.

I see no problem with your device tree as you did.

Best regards,
Aldo.

[petero5]

Hi Aldo, thank you for confirming!