Re: [PATCH 2/4] pwm: rockchip: Allow polarity invert on rk3288

From: Doug Anderson
Date: Tue Aug 19 2014 - 12:05:26 EST


Thierry

On Tue, Aug 19, 2014 at 12:18 AM, Thierry Reding
<thierry.reding@xxxxxxxxx> wrote:
> On Mon, Aug 18, 2014 at 10:09:07AM -0700, Doug Anderson wrote:
> [...]
>> diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c
>> #define PWM_LP_DISABLE (0 << 8)
>>
>> @@ -32,6 +34,7 @@ struct rockchip_pwm_chip {
>> struct pwm_chip chip;
>> struct clk *clk;
>> const struct rockchip_pwm_data *data;
>> + enum pwm_polarity polarity;
>
> Why do you need this field? struct pwm_device already has a copy of it.

OK, good point.


>> @@ -74,10 +78,14 @@ static void rockchip_pwm_set_enable_v2(struct pwm_chip *chip, bool enable)
>> {
>> struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
>> u32 enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
>> - PWM_CONTINUOUS | PWM_DUTY_POSITIVE |
>> - PWM_INACTIVE_NEGATIVE;
>> + PWM_CONTINUOUS;
>> u32 val;
>>
>> + if (pc->polarity == PWM_POLARITY_INVERSED)
>> + enable_conf |= PWM_DUTY_NEGATIVE | PWM_INACTIVE_POSITIVE;
>> + else
>> + enable_conf |= PWM_DUTY_POSITIVE | PWM_INACTIVE_NEGATIVE;
>
> I have a feeling you're going to answer the above question with: "Because
> it's needed here". If so, my reply would be: "Then this function should
> take a struct pwm_device instead of struct pwm_chip."

OK. I've chosen to have it take a pwm_device AND a pwm_chip. It is a
little redundant because a pwm_device has a pointer to its pwm_chip,
but it follows the lead of all of the callbacks in "struct pwm_ops".
If you'd like me to spin it to take only a pwm_device I'm happy to.


>
>> @@ -173,6 +195,7 @@ static const struct rockchip_pwm_data pwm_data_v2 = {
>> .ctrl = 0x0c,
>> },
>> .prescaler = 1,
>> + .has_invert = 1,
>
> Since has_invert is a boolean, the proper value here would be "true".

Done.


>> @@ -228,6 +252,10 @@ static int rockchip_pwm_probe(struct platform_device *pdev)
>> pc->data = id->data;
>> pc->chip.dev = &pdev->dev;
>> pc->chip.ops = &rockchip_pwm_ops;
>> + if (pc->data->has_invert) {
>> + pc->chip.of_xlate = of_pwm_xlate_with_flags;
>> + pc->chip.of_pwm_n_cells = 3;
>> + }
>> pc->chip.base = -1;
>> pc->chip.npwm = 1;
>
> I suggest to rewrite the above as follows for readability:
>
> pc->data = id->data;
> pc->chip.dev = &pdev->dev;
> pc->chip.ops = &rockchip_pwm_ops;
> pc->chip.base = -1;
> pc->chip.npwm = 1;

Done.


> + if (pc->data->has_invert) {
> + pc->chip.of_xlate = of_pwm_xlate_with_flags;
> + pc->chip.of_pwm_n_cells = 3;
> + }
>
> Thierry
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