linux-kernel - Re: [DMARC error][DKIM error] [PATCH v7 1/2] pwm: meson: Add support for Amlogic S4 PWM

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Date: Wed, 12 Jun 2024 10:15:19 +0200
From: Jerome Brunet <jbrunet@...libre.com>
To: George Stark <gnstark@...utedevices.com>
Cc: <kelvin.zhang@...ogic.com>,  Rob Herring <robh@...nel.org>,  Krzysztof
 Kozlowski <krzk+dt@...nel.org>,  Martin Blumenstingl
 <martin.blumenstingl@...glemail.com>,  Kevin Hilman
 <khilman@...libre.com>,  Neil Armstrong <neil.armstrong@...aro.org>,  Uwe
 Kleine-König <u.kleine-koenig@...gutronix.de>,  Conor
 Dooley
 <conor+dt@...nel.org>,  <linux-pwm@...r.kernel.org>,
  <linux-arm-kernel@...ts.infradead.org>,
  <linux-amlogic@...ts.infradead.org>,  <linux-kernel@...r.kernel.org>,
  <devicetree@...r.kernel.org>,  Junyi Zhao <junyi.zhao@...ogic.com>
Subject: Re: [DMARC error][DKIM error] [PATCH v7 1/2] pwm: meson: Add
 support for Amlogic S4 PWM

On Wed 05 Jun 2024 at 15:12, George Stark <gnstark@...utedevices.com> wrote:

> Hello Kelvin, Junyi
>
> On 6/5/24 05:44, Kelvin Zhang via B4 Relay wrote:
>> From: Junyi Zhao <junyi.zhao@...ogic.com>
>> Add support for Amlogic S4 PWM.
>> Signed-off-by: Junyi Zhao <junyi.zhao@...ogic.com>
>> Signed-off-by: Kelvin Zhang <kelvin.zhang@...ogic.com>
>> ---
>>   drivers/pwm/pwm-meson.c | 36 ++++++++++++++++++++++++++++++++++++
>>   1 file changed, 36 insertions(+)
>> diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c
>> index b2f97dfb01bb..4f01847525b2 100644
>> --- a/drivers/pwm/pwm-meson.c
>> +++ b/drivers/pwm/pwm-meson.c
>> @@ -460,6 +460,34 @@ static int meson_pwm_init_channels_meson8b_v2(struct pwm_chip *chip)
>>   	return meson_pwm_init_clocks_meson8b(chip, mux_parent_data);
>>   }
>>   +static void meson_pwm_s4_put_clk(void *data)
>> +{
>> +	struct clk *clk = data;
>> +
>> +	clk_put(clk);
>> +}
>> +
>> +static int meson_pwm_init_channels_s4(struct pwm_chip *chip)
>> +{
>> +	struct device *dev = pwmchip_parent(chip);
>> +	struct device_node *np = dev->of_node;
>> +	struct meson_pwm *meson = to_meson_pwm(chip);
>> +	int i, ret;
>> +
>> +	for (i = 0; i < MESON_NUM_PWMS; i++) {
>> +		meson->channels[i].clk = of_clk_get(np, i);
>> +		if (IS_ERR(meson->channels[i].clk)) {
>> +			ret = PTR_ERR(meson->channels[i].clk);
>> +			dev_err_probe(dev, ret, "Failed to get clk\n");
>> +			return ret;
>> +		}
>> +		devm_add_action_or_reset(dev, meson_pwm_s4_put_clk,
>> +					 meson->channels[i].clk);
>
> devm_add_action_or_reset() result should be checked
>
>> +	}
>> +
>> +	return 0;
>> +}
>
> You can rewrite it a bit to always have a single allocation for devm node:
>
> static void meson_pwm_s4_put_clk(void *data)
> {
> 	struct meson_pwm *meson = data;
> 	int i;
>
> 	for (i = 0; i < MESON_NUM_PWMS; i++)
> 		clk_put(meson->channels[i].clk);
> }

This has already been discussed on v6.

This make the code un-necessarily complex and potentially put clock that
have not even been claimed.

>
> static int meson_pwm_init_channels_s4(struct pwm_chip *chip)
> {
> 	struct device *dev = pwmchip_parent(chip);
> 	struct device_node *np = dev->of_node;
> 	struct meson_pwm *meson = to_meson_pwm(chip);
> 	int i, ret;
>
> 	ret = devm_add_action(dev, meson_pwm_s4_put_clk, meson);
> 	if (ret)
> 		return ret;
>
> 	for (i = 0; i < MESON_NUM_PWMS; i++) {
> 		meson->channels[i].clk = of_clk_get(np, i);
> 		if (IS_ERR(meson->channels[i].clk)) {
> 			ret = PTR_ERR(meson->channels[i].clk);
> 			dev_err_probe(dev, ret, "Failed to get clk\n");
> 			return ret;
> 		}
> 	}
>
> 	return 0;
> }

-- 
Jerome