TDA4VM: How to use PWM3 on TDA4/J721E?

Veitch Kyrie

Intellectual 500 points

Part Number: TDA4VM

Hi TI，

I have the following questions on TDA4VM PWM:

How to enable PWM instances of TDA4VM?
How to exercise from user space the TI J7/TDA4x PWM interface?

I add device-tree at dts:

	mypru_icssg0_pwm3_pins_default: mypru_icssg0_pwm3_pins_default {
		pinctrl-single,pins = <
			J721E_IOPAD(0xb0, PIN_OUTPUT, 3) /* (AF28) PRG0_PRU0_GPO0.PRG0_PWM3_A0 */
		>;
	};

	timer3: timer@2430000 {
        compatible = "ti,omap3430-timer";
        reg = <0x2430000 0x400>;
    	interrupts = <GIC_SPI 227 IRQ_TYPE_LEVEL_HIGH>;
        ti,hwmods = "timer3";
		ti,timer-pwm;
	    status = "okay";
	};

	pwm3: dmtimer-pwm@3 {
           compatible = "ti,omap-dmtimer-pwm";
           ti,timers = <&timer3>;
           #pwm-cells = <3>;
       	   pinctrl-names = "default";
		   pinctrl-0 = <&mypru_icssg0_pwm3_pins_default>;
		   status = "okay";
    };

enbale the related macros at tisdk_j7-evm_defconfig：

--- ../arch/arm64/configs/tisdk_j7-evm_defconfig    
+++ ../arch/arm64/configs/tisdk_j7-evm_defconfig        
@@ -6444,6 +6444,8 @@
 # CONFIG_PWM_PCA9685 is not set
 CONFIG_PWM_TIECAP=y
 CONFIG_PWM_TIEHRPWM=y
+CONFIG_OMAP_DM_TIMER=y
+CONFIG_PWM_OMAP_DMTIMER=y

Then I got compliing error:

implicit declaration of function ‘__omap_dm_timer_init_regs’; did you mean ‘omap_dm_timer_write_reg’? [-Werror=implicit-function-declaration]

Thanks

thanks

over 3 years ago

0 Keerthy J over 3 years ago

TI__Guru**** 166330 points

Hi,

DMTimer support is NOT present for TDA4VM.

For PWM Support please take a look at this FAQ: https://e2e.ti.com/support/processors-group/processors/f/processors-forum/982074/faq-tda4vm-dra829v-j721e-how-to-enable-ehrpwm-on-j7-evm-using-linux

Best Regards,
Keerthy

0 Veitch Kyrie over 3 years ago in reply to Keerthy J

Intellectual 500 points

Hi Keerthy,

thanks for your reply, after applying that patch I got below failures, could you help? I'm using SDK8.0, and I have double checked the DT

# dmesg | grep ti-syscon                                                            
[    0.571881] ti-syscon-gate-clk interconnect@100000:clk0: failed to find parent regmap
[    0.579896] ti-syscon-gate-clk: probe of interconnect@100000:clk0 failed with error -22

0 Keerthy J over 3 years ago in reply to Veitch Kyrie

TI__Guru**** 166330 points

Hi,

5.10 kernel needs some changes in DT:

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/982074/faq-tda4vm-dra829v-j721e-how-to-enable-ehrpwm-on-j7-evm-using-linux/4036779#4036779

I have responded with the fix in that FAQ.

That should fix the issue you are facing.

Closing this thread.

- Keerthy

0 Veitch Kyrie over 3 years ago in reply to Keerthy J

Intellectual 500 points

Hi Keerthy,

This thread will help, could you please confirm one more question, that's I found in the 5.10 kernel DT, you modify the device-id of epwm0 to 40, but I check the J721E Clock Identifiers, the deivce-id of epwm0 should be 83 instead of 40, could you help to clarify this question? After that, this thread could be closed. thanks

In 5.10 DT:

ehrpwm0:pwm@3000000{
    compatible="ti,am654-ehrpwm","ti,am3352-ehrpwm";
    #pwm-cells=<3>;
    reg = <0x0 0x3000000 0x0 0x100>;
    power-domains = <&k3_pds 40 TI_SCI_PD_EXCLUSIVE>;
    clocks = <&ehrpwm_tbclk 0>, <&k3_clks 40 0>;
    clock-names = "tbclk", "fck";
};

In J721E Clock Identifiers：

+1 Keerthy J over 3 years ago in reply to Veitch Kyrie

TI__Guru**** 166330 points

Hi,

https://git.ti.com/gitweb?p=ti-linux-kernel/ti-linux-kernel.git;a=blob;f=arch/arm64/boot/dts/ti/k3-am65-main.dtsi;h=0b229fe9d2bc440c09447f2cea9fbc293d27aef9;hb=refs/heads/ti-linux-5.10.y#l350

This is for AM65 SoC. This was a reference on how to fix the issue you faced.

[    0.579896] ti-syscon-gate-clk: probe of interconnect@100000:clk0 failed with error -22

So the original numbers hold good like you have mentioned 83, 84 etc.

Closing this issue.

- Keerthy

Processors

Processors forum

TDA4VM: How to use PWM3 on TDA4/J721E?