On Mon, Mar 30, 2020 at 04:57:13PM +0200, Ahmad Fatoum wrote:
> From: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
>
> Use pwm_apply_state we can avoid having to store PWM state in the
> instance structure and in future we have an easy way to support new
> parameters like inverted duty cycle.
>
> Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
> ---
> drivers/video/backlight-pwm.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/video/backlight-pwm.c b/drivers/video/backlight-pwm.c
> index 9111a42d7544..8b6494dac929 100644
> --- a/drivers/video/backlight-pwm.c
> +++ b/drivers/video/backlight-pwm.c
> @@ -33,7 +33,6 @@ struct pwm_backlight {
> struct backlight_device backlight;
> struct pwm_device *pwm;
> struct regulator *power;
> - uint32_t period;
> unsigned int *levels;
> int enable_gpio;
> int enable_active_high;
> @@ -91,13 +90,16 @@ static int backlight_pwm_disable(struct pwm_backlight *pwm_backlight)
> static int compute_duty_cycle(struct pwm_backlight *pwm_backlight, int brightness)
> {
> int duty_cycle;
> + struct pwm_state state;
> +
> + pwm_get_state(pwm_backlight->pwm, &state);
>
> if (pwm_backlight->levels)
> duty_cycle = pwm_backlight->levels[brightness];
> else
> duty_cycle = brightness;
>
> - return duty_cycle * pwm_backlight->period / pwm_backlight->scale;
> + return duty_cycle * state.period_ns / pwm_backlight->scale;
> }
>
> static int backlight_pwm_set(struct backlight_device *backlight,
> @@ -105,9 +107,11 @@ static int backlight_pwm_set(struct backlight_device *backlight,
> {
> struct pwm_backlight *pwm_backlight = container_of(backlight,
> struct pwm_backlight, backlight);
> + struct pwm_state state;
>
> - pwm_config(pwm_backlight->pwm, compute_duty_cycle(pwm_backlight, brightness),
> - pwm_backlight->period);
> + pwm_get_state(pwm_backlight->pwm, &state);
You read the current pwm state here...
> + state.duty_ns = compute_duty_cycle(pwm_backlight, brightness);
and once again in compute_duty_cycle(). I think it would be nicer to
reorganize this a bit, maybe pass the state to compute_duty_cycle.
> + pwm_apply_state(pwm_backlight->pwm, &state);
>
> if (brightness)
> return backlight_pwm_enable(pwm_backlight);
I would assume that if you switch to the pwm_apply_state API then you do
it entirely. backlight_pwm_enable() still uses the old API to enable the
PWM.
Sascha
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