Re: [PATCH v4 4/6] pwm: meson: use device data to carry information around

[Jerome Brunet]

On Mon 05 Feb 2024 at 18:12, Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> wrote:

> [[PGP Signed Part:Undecided]]
> On Fri, Dec 22, 2023 at 12:16:52PM +0100, Jerome Brunet wrote:
>> Use struct device data to carry the information data around, instead
>> of embedded the pwm structure in it and using container_of()
>> 
>> Doing so works just as well and makes it a little easier to add setup
>> callback depending on the DT compatible.
>> 
>> Signed-off-by: Jerome Brunet <jbrunet@xxxxxxxxxxxx>
>> ---
>>  drivers/pwm/pwm-meson.c | 39 +++++++++++++++++++++++----------------
>>  1 file changed, 23 insertions(+), 16 deletions(-)
>> 
>> diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c
>> index ef50c337f444..15c44185d784 100644
>> --- a/drivers/pwm/pwm-meson.c
>> +++ b/drivers/pwm/pwm-meson.c
>> @@ -101,7 +101,6 @@ struct meson_pwm_data {
>>  };
>>  
>>  struct meson_pwm {
>> -	struct pwm_chip chip;
>>  	const struct meson_pwm_data *data;
>>  	struct meson_pwm_channel channels[MESON_NUM_PWMS];
>>  	void __iomem *base;
>> @@ -114,7 +113,7 @@ struct meson_pwm {
>>  
>>  static inline struct meson_pwm *to_meson_pwm(struct pwm_chip *chip)
>>  {
>> -	return container_of(chip, struct meson_pwm, chip);
>> +	return dev_get_drvdata(chip->dev);
>>  }
>>  
>>  static int meson_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
>> @@ -146,6 +145,7 @@ static int meson_pwm_calc(struct meson_pwm *meson, struct pwm_device *pwm,
>>  			  const struct pwm_state *state)
>>  {
>>  	struct meson_pwm_channel *channel = &meson->channels[pwm->hwpwm];
>> +	struct device *dev = pwm->chip->dev;
>>  	unsigned int cnt, duty_cnt;
>>  	unsigned long fin_freq;
>>  	u64 duty, period, freq;
>> @@ -168,19 +168,19 @@ static int meson_pwm_calc(struct meson_pwm *meson, struct pwm_device *pwm,
>>  
>>  	fin_freq = clk_round_rate(channel->clk, freq);
>>  	if (fin_freq == 0) {
>> -		dev_err(meson->chip.dev, "invalid source clock frequency\n");
>> +		dev_err(dev, "invalid source clock frequency\n");
>>  		return -EINVAL;
>>  	}
>>  
>> -	dev_dbg(meson->chip.dev, "fin_freq: %lu Hz\n", fin_freq);
>> +	dev_dbg(dev, "fin_freq: %lu Hz\n", fin_freq);
>>  
>>  	cnt = div_u64(fin_freq * period, NSEC_PER_SEC);
>>  	if (cnt > 0xffff) {
>> -		dev_err(meson->chip.dev, "unable to get period cnt\n");
>> +		dev_err(dev, "unable to get period cnt\n");
>>  		return -EINVAL;
>>  	}
>>  
>> -	dev_dbg(meson->chip.dev, "period=%llu cnt=%u\n", period, cnt);
>> +	dev_dbg(dev, "period=%llu cnt=%u\n", period, cnt);
>>  
>>  	if (duty == period) {
>>  		channel->hi = cnt;
>> @@ -191,7 +191,7 @@ static int meson_pwm_calc(struct meson_pwm *meson, struct pwm_device *pwm,
>>  	} else {
>>  		duty_cnt = div_u64(fin_freq * duty, NSEC_PER_SEC);
>>  
>> -		dev_dbg(meson->chip.dev, "duty=%llu duty_cnt=%u\n", duty, duty_cnt);
>> +		dev_dbg(dev, "duty=%llu duty_cnt=%u\n", duty, duty_cnt);
>>  
>>  		channel->hi = duty_cnt;
>>  		channel->lo = cnt - duty_cnt;
>> @@ -214,7 +214,7 @@ static void meson_pwm_enable(struct meson_pwm *meson, struct pwm_device *pwm)
>>  
>>  	err = clk_set_rate(channel->clk, channel->rate);
>>  	if (err)
>> -		dev_err(meson->chip.dev, "setting clock rate failed\n");
>> +		dev_err(pwm->chip->dev, "setting clock rate failed\n");
>>  
>>  	spin_lock_irqsave(&meson->lock, flags);
>>  
>> @@ -425,10 +425,10 @@ static const struct of_device_id meson_pwm_matches[] = {
>>  };
>>  MODULE_DEVICE_TABLE(of, meson_pwm_matches);
>>  
>> -static int meson_pwm_init_channels(struct meson_pwm *meson)
>> +static int meson_pwm_init_channels(struct device *dev)
>>  {
>>  	struct clk_parent_data mux_parent_data[MESON_NUM_MUX_PARENTS] = {};
>> -	struct device *dev = meson->chip.dev;
>> +	struct meson_pwm *meson = dev_get_drvdata(dev);
>>  	unsigned int i;
>>  	char name[255];
>>  	int err;
>> @@ -438,7 +438,7 @@ static int meson_pwm_init_channels(struct meson_pwm *meson)
>>  		mux_parent_data[i].name = meson->data->parent_names[i];
>>  	}
>>  
>> -	for (i = 0; i < meson->chip.npwm; i++) {
>> +	for (i = 0; i < MESON_NUM_PWMS; i++) {
>>  		struct meson_pwm_channel *channel = &meson->channels[i];
>>  		struct clk_parent_data div_parent = {}, gate_parent = {};
>>  		struct clk_init_data init = {};
>> @@ -519,28 +519,35 @@ static int meson_pwm_init_channels(struct meson_pwm *meson)
>>  static int meson_pwm_probe(struct platform_device *pdev)
>>  {
>>  	struct meson_pwm *meson;
>> +	struct pwm_chip *chip;
>>  	int err;
>>  
>> +	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
>> +	if (!chip)
>> +		return -ENOMEM;
>> +
>>  	meson = devm_kzalloc(&pdev->dev, sizeof(*meson), GFP_KERNEL);
>>  	if (!meson)
>>  		return -ENOMEM;
>>  
>> +	platform_set_drvdata(pdev, meson);
>> +
>>  	meson->base = devm_platform_ioremap_resource(pdev, 0);
>>  	if (IS_ERR(meson->base))
>>  		return PTR_ERR(meson->base);
>>  
>>  	spin_lock_init(&meson->lock);
>> -	meson->chip.dev = &pdev->dev;
>> -	meson->chip.ops = &meson_pwm_ops;
>> -	meson->chip.npwm = MESON_NUM_PWMS;
>> +	chip->dev = &pdev->dev;
>> +	chip->ops = &meson_pwm_ops;
>> +	chip->npwm = MESON_NUM_PWMS;
>>  
>>  	meson->data = of_device_get_match_data(&pdev->dev);
>>  
>> -	err = meson_pwm_init_channels(meson);
>> +	err = meson_pwm_init_channels(&pdev->dev);
>>  	if (err < 0)
>>  		return err;
>>  
>> -	err = devm_pwmchip_add(&pdev->dev, &meson->chip);
>> +	err = devm_pwmchip_add(&pdev->dev, chip);
>>  	if (err < 0)
>>  		return dev_err_probe(&pdev->dev, err,
>>  				     "failed to register PWM chip\n");
>
> Parts of this change overlap with plans I have for this driver. I

It does overlap indeed. I'll drop this one while rebasing

> reworked the series a bit now, also affecting the meson driver, the
> previous submission is available at
> https://lore.kernel.org/linux-pwm/bf6f7c6253041f60ee8f35b5c9c9e8d595332fb0.1706182805.git.u.kleine-koenig@xxxxxxxxxxxxxx
>
> I don't see the nice benefit of this patch yet, but I assume this will
> become clearer when I check the next patch.
>
> Best regards
> Uwe


-- 
Jerome