linux-kernel - Re: [PATCH] pwm: tiehrpwm: Enable EHRPWM controller before setting configuration

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Message-ID: <e885a4dd-fcde-4c8a-a819-caf707360134@ti.com>
Date: Wed, 7 Jan 2026 11:08:15 +0530
From: Gokul Praveen <g-praveen@...com>
To: "Kumar, Udit" <u-kumar1@...com>, <j-keerthy@...com>,
	<ukleinek@...nel.org>, <linux-pwm@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
CC: <n-francis@...com>, Gokul Praveen <g-praveen@...com>
Subject: Re: [PATCH] pwm: tiehrpwm: Enable EHRPWM controller before setting
 configuration


On 06/01/26 18:57, Kumar, Udit wrote:
> 
> On 1/6/2026 4:24 PM, Gokul Praveen wrote:
>> The period and duty cycle configurations does not get reflected
>> after setting them using sysfs nodes. This is because at the
>> end of ehrpwm_pwm_config function, the put_sync function is
>> called which resets the hardware.
>>
>> Fix it by preventing the pwm controller from going into
>> low-power mode.
>>
>> 'Fixes: 5f027d9b83db("pwm: tiehrpwm: Implement
>> .apply() callback")'
>>
>> Signed-off-by: Gokul Praveen <g-praveen@...com>
> 
> No new line,  between Fixes and Signed-off-by Please ,
> 
> You can drop ' before fixes.
> 
> rest LGTM.

Sure, Udit. Thanks for that.

Best Regards
Gokul Praveen
> 
> 
>> ---
>>   drivers/pwm/pwm-tiehrpwm.c | 22 +++++++++++++---------
>>   1 file changed, 13 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/pwm/pwm-tiehrpwm.c b/drivers/pwm/pwm-tiehrpwm.c
>> index 7a86cb090f76..408aed70be8c 100644
>> --- a/drivers/pwm/pwm-tiehrpwm.c
>> +++ b/drivers/pwm/pwm-tiehrpwm.c
>> @@ -237,7 +237,6 @@ static int ehrpwm_pwm_config(struct pwm_chip 
>> *chip, struct pwm_device *pwm,
>>       if (period_cycles < 1)
>>           period_cycles = 1;
>> -    pm_runtime_get_sync(pwmchip_parent(chip));
>>       /* Update clock prescaler values */
>>       ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_CLKDIV_MASK, tb_divval);
>> @@ -290,12 +289,11 @@ static int ehrpwm_pwm_config(struct pwm_chip 
>> *chip, struct pwm_device *pwm,
>>       if (!(duty_cycles > period_cycles))
>>           ehrpwm_write(pc->mmio_base, cmp_reg, duty_cycles);
>> -    pm_runtime_put_sync(pwmchip_parent(chip));
>> -
>>       return 0;
>>   }
>> -static int ehrpwm_pwm_enable(struct pwm_chip *chip, struct pwm_device 
>> *pwm)
>> +static int ehrpwm_pwm_enable(struct pwm_chip *chip, struct pwm_device 
>> *pwm,
>> +                const struct pwm_state *state)
>>   {
>>       struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
>>       u16 aqcsfrc_val, aqcsfrc_mask;
>> @@ -304,6 +302,13 @@ static int ehrpwm_pwm_enable(struct pwm_chip 
>> *chip, struct pwm_device *pwm)
>>       /* Leave clock enabled on enabling PWM */
>>       pm_runtime_get_sync(pwmchip_parent(chip));
>> +    ret = ehrpwm_pwm_config(chip, pwm, state->duty_cycle, state- 
>> >period, state->polarity);
>> +
>> +    if (ret) {
>> +        pm_runtime_put_sync(pwmchip_parent(chip));
>> +        return ret;
>> +    }
>> +
>>       /* Disabling Action Qualifier on PWM output */
>>       if (pwm->hwpwm) {
>>           aqcsfrc_val = AQCSFRC_CSFB_FRCDIS;
>> @@ -391,12 +396,11 @@ static int ehrpwm_pwm_apply(struct pwm_chip 
>> *chip, struct pwm_device *pwm,
>>           return 0;
>>       }
>> -    err = ehrpwm_pwm_config(chip, pwm, state->duty_cycle, state- 
>> >period, state->polarity);
>> -    if (err)
>> -        return err;
>> -
>>       if (!enabled)
>> -        err = ehrpwm_pwm_enable(chip, pwm);
>> +        err = ehrpwm_pwm_enable(chip, pwm, state);
>> +    else
>> +        err = ehrpwm_pwm_config(chip, pwm, state->duty_cycle,
>> +                    state->period, state->polarity);
>>       return err;
>>   }