From: Rudraksha Gupta <guptarud@gmail.com>

Add a pwm-vibrator to expressatt. Currently this vibrates only at 100%

Signed-off-by: Rudraksha Gupta <guptarud@gmail.com>
---
Add a pwm-vibrator to expressatt. Currently this vibrates only at 100%

Link:
- https://github.com/LineageOS/android_kernel_samsung_d2/blob/stable/cm-12.0-YNG4N/arch/arm/mach-msm/board-express.c#L1767
- https://github.com/LineageOS/android_kernel_samsung_d2/blob/stable/cm-12.0-YNG4N/drivers/motor/Makefile#L5

Test:
=====================
samsung-expressatt:~$ dmesg | grep vibra
[   79.892226] input: pwm-vibrator as /devices/platform/vibrator/input/input4
samsung-expressatt:~$ fftest /dev/input/event4 
Force feedback test program.
HOLD FIRMLY YOUR WHEEL OR JOYSTICK TO PREVENT DAMAGES

Device /dev/input/event4 opened
Features:
  * Absolute axes: 
    [00 00 00 00 00 00 00 00 ]
  * Relative axes: 
    [00 00 ]
  * Force feedback effects types: Periodic, Rumble, Gain, 
    Force feedback periodic effects: Square, Triangle, Sine, 
    [00 00 00 00 00 00 00 00 00 00 03 07 01 00 00 00 ]
  * Number of simultaneous effects: 16

Setting master gain to 75% ... OK
Uploading effect #0 (Periodic sinusoidal) ... OK (id 0)
Uploading effect #1 (Constant) ... Error: Invalid argument
Uploading effect #2 (Spring) ... Error: Invalid argument
Uploading effect #3 (Damper) ... Error: Invalid argument
Uploading effect #4 (Strong rumble, with heavy motor) ... OK (id 1)
Uploading effect #5 (Weak rumble, with light motor) ... OK (id 2)
Enter effect number, -1 to exit
0
Now Playing: Sine vibration
Enter effect number, -1 to exit
[  157.967092] pwm-vibrator vibrator: failed to apply pwm state: -16
[  158.017952] pwm-vibrator vibrator: failed to apply pwm state: -16

Note: This patch was assisted with Claude and cleaned up by me.
---
 .../dts/qcom/qcom-msm8960-samsung-expressatt.dts   | 44 ++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/arch/arm/boot/dts/qcom/qcom-msm8960-samsung-expressatt.dts b/arch/arm/boot/dts/qcom/qcom-msm8960-samsung-expressatt.dts
index c4b98af6955d..09443df0fdce 100644
--- a/arch/arm/boot/dts/qcom/qcom-msm8960-samsung-expressatt.dts
+++ b/arch/arm/boot/dts/qcom/qcom-msm8960-samsung-expressatt.dts
@@ -87,6 +87,35 @@ touchkey@20 {
 			linux,keycodes = <KEY_MENU KEY_BACK>;
 		};
 	};
+
+	gp1_pwm: pwm {
+		compatible = "clk-pwm";
+		#pwm-cells = <2>;
+		clocks = <&gcc GP1_CLK>;
+	};
+
+	/* TODO: Vary the frequency besides being 0% or 100% */
+	vibrator {
+		compatible = "pwm-vibrator";
+		pwms = <&gp1_pwm 0 54347 0>;  /* ~18.4 kHz */
+		pwm-names = "enable";
+		enable-gpios = <&pm8921_gpio 4 GPIO_ACTIVE_HIGH>;
+		vcc-supply = <&vdd_haptics>;
+
+		pinctrl-names = "default";
+		pinctrl-0 = <&vib_pwm_gpio>;
+	};
+
+	vdd_haptics: vdd-haptics-regulator {
+		compatible = "regulator-fixed";
+		regulator-name = "vdd_haptics";
+		gpio = <&tlmm 47 GPIO_ACTIVE_HIGH>;
+		enable-active-high;
+		regulator-boot-on;
+
+		pinctrl-names = "default";
+		pinctrl-0 = <&haptics_pwr_en>;
+	};
 };
 
 &gsbi2 {
@@ -241,6 +270,21 @@ touchkey_i2c_pins: touchkey-i2c-state {
 		bias-disable;
 	};
 
+	haptics_pwr_en: haptics-pwr-en-state {
+		pins = "gpio47";
+		function = "gpio";
+		drive-strength = <2>;
+		bias-disable;
+		output-low;
+	};
+
+	vib_pwm_gpio: vib-pwm-gpio-state {
+		pins = "gpio70";
+		function = "gp_clk_1b";
+		drive-strength = <2>;
+		bias-disable;
+	};
+
 	touchkey_irq_pin: touchkey-irq-state {
 		pins = "gpio52";
 		function = "gpio";

---
base-commit: b066d7751f99fabaa07939006233781536ab16e5
change-id: 20251211-expressatt-vibrator-de557aa8f7d4
prerequisite-message-id: <20251205-expressatt-touchkey-v1-1-1444b927c9f3@gmail.com>
prerequisite-patch-id: 8de4de7909722ccaf385c4224f25a623eaa72c28

Best regards,
-- 
Rudraksha Gupta <guptarud@gmail.com>

On 12/11/25 11:23 AM, Rudraksha Gupta via B4 Relay wrote:
> From: Rudraksha Gupta <guptarud@gmail.com>
> 
> Add a pwm-vibrator to expressatt. Currently this vibrates only at 100%
> 
> Signed-off-by: Rudraksha Gupta <guptarud@gmail.com>
> ---
> Add a pwm-vibrator to expressatt. Currently this vibrates only at 100%
> 
> Link:
> - https://github.com/LineageOS/android_kernel_samsung_d2/blob/stable/cm-12.0-YNG4N/arch/arm/mach-msm/board-express.c#L1767
> - https://github.com/LineageOS/android_kernel_samsung_d2/blob/stable/cm-12.0-YNG4N/drivers/motor/Makefile#L5
> 
> Test:
> =====================
> samsung-expressatt:~$ dmesg | grep vibra
> [   79.892226] input: pwm-vibrator as /devices/platform/vibrator/input/input4
> samsung-expressatt:~$ fftest /dev/input/event4 
> Force feedback test program.
> HOLD FIRMLY YOUR WHEEL OR JOYSTICK TO PREVENT DAMAGES
> 
> Device /dev/input/event4 opened
> Features:
>   * Absolute axes: 
>     [00 00 00 00 00 00 00 00 ]
>   * Relative axes: 
>     [00 00 ]
>   * Force feedback effects types: Periodic, Rumble, Gain, 
>     Force feedback periodic effects: Square, Triangle, Sine, 
>     [00 00 00 00 00 00 00 00 00 00 03 07 01 00 00 00 ]
>   * Number of simultaneous effects: 16
> 
> Setting master gain to 75% ... OK
> Uploading effect #0 (Periodic sinusoidal) ... OK (id 0)
> Uploading effect #1 (Constant) ... Error: Invalid argument
> Uploading effect #2 (Spring) ... Error: Invalid argument
> Uploading effect #3 (Damper) ... Error: Invalid argument

Looks like this is because GP1_CLK does not implement .set_duty_cycle..

The downstream driver you linked to does so in a terribly hacky way
(from the vibrator driver and not the clock driver):

https://github.com/LineageOS/android_kernel_samsung_d2/blob/cm-14.1/drivers/motor/immvibespi.c#L53

Upstream, we have an implementation for clk_rcg*2*_ops, whereas 8960
uses clk_rcg_ops.

They look very similar though, perhaps you can hack it up..

One thing to note is that you're passing GP1_CLK to the clk-pwm (as
you should), but we need to do clk_set_duty_cycle on its parent,
GP1_CLK*_SRC*. The framework will take care of this:

```
--- drivers/clk/clk.c
	if (!core->ops->get_duty_cycle)
		return clk_core_update_duty_cycle_parent_nolock(core);
```

so long as you add CLK_DUTY_CYCLE_PARENT to the child

[...]
> +	/* TODO: Vary the frequency besides being 0% or 100% */
> +	vibrator {
> +		compatible = "pwm-vibrator";
> +		pwms = <&gp1_pwm 0 54347 0>;  /* ~18.4 kHz */
> +		pwm-names = "enable";
> +		enable-gpios = <&pm8921_gpio 4 GPIO_ACTIVE_HIGH>;
> +		vcc-supply = <&vdd_haptics>;
> +
> +		pinctrl-names = "default";
> +		pinctrl-0 = <&vib_pwm_gpio>;

pinctrl-n
pinctrl-names

please, both occurences

> +	};
> +
> +	vdd_haptics: vdd-haptics-regulator {
> +		compatible = "regulator-fixed";
> +		regulator-name = "vdd_haptics";
> +		gpio = <&tlmm 47 GPIO_ACTIVE_HIGH>;
> +		enable-active-high;
> +		regulator-boot-on;
> +
> +		pinctrl-names = "default";
> +		pinctrl-0 = <&haptics_pwr_en>;
> +	};
>  };
>  
>  &gsbi2 {
> @@ -241,6 +270,21 @@ touchkey_i2c_pins: touchkey-i2c-state {
>  		bias-disable;
>  	};
>  
> +	haptics_pwr_en: haptics-pwr-en-state {
> +		pins = "gpio47";
> +		function = "gpio";
> +		drive-strength = <2>;
> +		bias-disable;
> +		output-low;

Drop output-low, the driver should take care of setting the state

Konrad

Hello Konrad,


On 12/16/25 06:22, Konrad Dybcio wrote:
> On 12/11/25 11:23 AM, Rudraksha Gupta via B4 Relay wrote:
>> From: Rudraksha Gupta <guptarud@gmail.com>
>>
>> Add a pwm-vibrator to expressatt. Currently this vibrates only at 100%
>>
>> Signed-off-by: Rudraksha Gupta <guptarud@gmail.com>
>> ---
>> Add a pwm-vibrator to expressatt. Currently this vibrates only at 100%
>>
>> Link:
>> - https://github.com/LineageOS/android_kernel_samsung_d2/blob/stable/cm-12.0-YNG4N/arch/arm/mach-msm/board-express.c#L1767
>> - https://github.com/LineageOS/android_kernel_samsung_d2/blob/stable/cm-12.0-YNG4N/drivers/motor/Makefile#L5
>>
>> Test:
>> =====================
>> samsung-expressatt:~$ dmesg | grep vibra
>> [   79.892226] input: pwm-vibrator as /devices/platform/vibrator/input/input4
>> samsung-expressatt:~$ fftest /dev/input/event4
>> Force feedback test program.
>> HOLD FIRMLY YOUR WHEEL OR JOYSTICK TO PREVENT DAMAGES
>>
>> Device /dev/input/event4 opened
>> Features:
>>    * Absolute axes:
>>      [00 00 00 00 00 00 00 00 ]
>>    * Relative axes:
>>      [00 00 ]
>>    * Force feedback effects types: Periodic, Rumble, Gain,
>>      Force feedback periodic effects: Square, Triangle, Sine,
>>      [00 00 00 00 00 00 00 00 00 00 03 07 01 00 00 00 ]
>>    * Number of simultaneous effects: 16
>>
>> Setting master gain to 75% ... OK
>> Uploading effect #0 (Periodic sinusoidal) ... OK (id 0)
>> Uploading effect #1 (Constant) ... Error: Invalid argument
>> Uploading effect #2 (Spring) ... Error: Invalid argument
>> Uploading effect #3 (Damper) ... Error: Invalid argument
> Looks like this is because GP1_CLK does not implement .set_duty_cycle..
>
> The downstream driver you linked to does so in a terribly hacky way
> (from the vibrator driver and not the clock driver):
>
> https://github.com/LineageOS/android_kernel_samsung_d2/blob/cm-14.1/drivers/motor/immvibespi.c#L53
>
> Upstream, we have an implementation for clk_rcg*2*_ops, whereas 8960
> uses clk_rcg_ops.
>
> They look very similar though, perhaps you can hack it up..
>
> One thing to note is that you're passing GP1_CLK to the clk-pwm (as
> you should), but we need to do clk_set_duty_cycle on its parent,
> GP1_CLK*_SRC*. The framework will take care of this:
>
> ```
> --- drivers/clk/clk.c
> 	if (!core->ops->get_duty_cycle)
> 		return clk_core_update_duty_cycle_parent_nolock(core);
> ```
>
> so long as you add CLK_DUTY_CYCLE_PARENT to the child
>
> [...]


Sorry for the delay, but I'm struggling to get this implemented. I have 
my in progress work here:

https://codeberg.org/LogicalErzor/linux/commit/4e7f94d9fdd1e4e1d688b2eb518494d710f157fb


I was able to get rid of the -16 error that was getting spammed when 
using fftest, but it is still showing

Uploading effect #1 (Constant) ... Error: Invalid argument
Uploading effect #2 (Spring) ... Error: Invalid argument
Uploading effect #3 (Damper) ... Error: Invalid argument


If you have any other insight on how to make the vibrator variable in 
intensity (it's still either 0% or 100%), please feel free to let me 
know. I will continue trying to hack away at it to see if I can get the 
variable intensity to work via fftest.
>> +	/* TODO: Vary the frequency besides being 0% or 100% */
>> +	vibrator {
>> +		compatible = "pwm-vibrator";
>> +		pwms = <&gp1_pwm 0 54347 0>;  /* ~18.4 kHz */
>> +		pwm-names = "enable";
>> +		enable-gpios = <&pm8921_gpio 4 GPIO_ACTIVE_HIGH>;
>> +		vcc-supply = <&vdd_haptics>;
>> +
>> +		pinctrl-names = "default";
>> +		pinctrl-0 = <&vib_pwm_gpio>;
> pinctrl-n
> pinctrl-names
>
> please, both occurences
>
>> +	};
>> +
>> +	vdd_haptics: vdd-haptics-regulator {
>> +		compatible = "regulator-fixed";
>> +		regulator-name = "vdd_haptics";
>> +		gpio = <&tlmm 47 GPIO_ACTIVE_HIGH>;
>> +		enable-active-high;
>> +		regulator-boot-on;
>> +
>> +		pinctrl-names = "default";
>> +		pinctrl-0 = <&haptics_pwr_en>;
>> +	};
>>   };
>>   
>>   &gsbi2 {
>> @@ -241,6 +270,21 @@ touchkey_i2c_pins: touchkey-i2c-state {
>>   		bias-disable;
>>   	};
>>   
>> +	haptics_pwr_en: haptics-pwr-en-state {
>> +		pins = "gpio47";
>> +		function = "gpio";
>> +		drive-strength = <2>;
>> +		bias-disable;
>> +		output-low;
> Drop output-low, the driver should take care of setting the state
>
> Konrad

On 1/29/26 8:55 AM, Rudraksha Gupta wrote:
> Hello Konrad,
> 
> 
> On 12/16/25 06:22, Konrad Dybcio wrote:
>> On 12/11/25 11:23 AM, Rudraksha Gupta via B4 Relay wrote:
>>> From: Rudraksha Gupta <guptarud@gmail.com>
>>>
>>> Add a pwm-vibrator to expressatt. Currently this vibrates only at 100%
>>>
>>> Signed-off-by: Rudraksha Gupta <guptarud@gmail.com>
>>> ---
>>> Add a pwm-vibrator to expressatt. Currently this vibrates only at 100%
>>>
>>> Link:
>>> - https://github.com/LineageOS/android_kernel_samsung_d2/blob/stable/cm-12.0-YNG4N/arch/arm/mach-msm/board-express.c#L1767
>>> - https://github.com/LineageOS/android_kernel_samsung_d2/blob/stable/cm-12.0-YNG4N/drivers/motor/Makefile#L5
>>>
>>> Test:
>>> =====================
>>> samsung-expressatt:~$ dmesg | grep vibra
>>> [   79.892226] input: pwm-vibrator as /devices/platform/vibrator/input/input4
>>> samsung-expressatt:~$ fftest /dev/input/event4
>>> Force feedback test program.
>>> HOLD FIRMLY YOUR WHEEL OR JOYSTICK TO PREVENT DAMAGES
>>>
>>> Device /dev/input/event4 opened
>>> Features:
>>>    * Absolute axes:
>>>      [00 00 00 00 00 00 00 00 ]
>>>    * Relative axes:
>>>      [00 00 ]
>>>    * Force feedback effects types: Periodic, Rumble, Gain,
>>>      Force feedback periodic effects: Square, Triangle, Sine,
>>>      [00 00 00 00 00 00 00 00 00 00 03 07 01 00 00 00 ]
>>>    * Number of simultaneous effects: 16
>>>
>>> Setting master gain to 75% ... OK
>>> Uploading effect #0 (Periodic sinusoidal) ... OK (id 0)
>>> Uploading effect #1 (Constant) ... Error: Invalid argument
>>> Uploading effect #2 (Spring) ... Error: Invalid argument
>>> Uploading effect #3 (Damper) ... Error: Invalid argument
>> Looks like this is because GP1_CLK does not implement .set_duty_cycle..
>>
>> The downstream driver you linked to does so in a terribly hacky way
>> (from the vibrator driver and not the clock driver):
>>
>> https://github.com/LineageOS/android_kernel_samsung_d2/blob/cm-14.1/drivers/motor/immvibespi.c#L53
>>
>> Upstream, we have an implementation for clk_rcg*2*_ops, whereas 8960
>> uses clk_rcg_ops.
>>
>> They look very similar though, perhaps you can hack it up..
>>
>> One thing to note is that you're passing GP1_CLK to the clk-pwm (as
>> you should), but we need to do clk_set_duty_cycle on its parent,
>> GP1_CLK*_SRC*. The framework will take care of this:
>>
>> ```
>> --- drivers/clk/clk.c
>>     if (!core->ops->get_duty_cycle)
>>         return clk_core_update_duty_cycle_parent_nolock(core);
>> ```
>>
>> so long as you add CLK_DUTY_CYCLE_PARENT to the child
>>
>> [...]
> 
> 
> Sorry for the delay, but I'm struggling to get this implemented. I have my in progress work here:
> 
> https://codeberg.org/LogicalErzor/linux/commit/4e7f94d9fdd1e4e1d688b2eb518494d710f157fb

The changes to drivers/clk/clk-pwm.c are unnecessary, you're using
clk-pwm (PWM implemented using a clock reference) and not pwm-clock
(clock implemented using a PWM reference)

> I was able to get rid of the -16 error that was getting spammed when using fftest, but it is still showing
> 
> Uploading effect #1 (Constant) ... Error: Invalid argument
> Uploading effect #2 (Spring) ... Error: Invalid argument
> Uploading effect #3 (Damper) ... Error: Invalid argument


Is there a chance you can pr_err the entire call stack from
pwm_vibrator_start() downwards and see where it fails?

As a guess, I'd check if you're not hitting the EINVAL return path in
clk_core_update_duty_cycle_nolock()


Konrad