Hi Uwe,
On Fri, Jan 24, 2020 at 05:54:08PM +0100, Uwe Kleine-König wrote:
> pwm_config(), pwm_enable() and pwm_disable() should get removed in the
> long run. So update the driver to use the atomic API that is here to
> stay.
>
> A few side effects:
>
> - led_pwm_set() now returns an error when setting the PWM fails.
> - During .probe() the PWM isn't disabled implicitly by pwm_apply_args()
> any more.
>
> Signed-off-by: Uwe Kleine-König <uwe@xxxxxxxxxxxxxxxxx>
> ---
> drivers/leds/leds-pwm.c | 41 +++++++++--------------------------------
> 1 file changed, 9 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c
> index b72fd89ff390..9111cdede0ee 100644
> --- a/drivers/leds/leds-pwm.c
> +++ b/drivers/leds/leds-pwm.c
> @@ -22,9 +22,8 @@
> struct led_pwm_data {
> struct led_classdev cdev;
> struct pwm_device *pwm;
> + struct pwm_state pwmstate;
> unsigned int active_low;
> - unsigned int period;
> - int duty;
> };
>
> struct led_pwm_priv {
> @@ -32,44 +31,29 @@ struct led_pwm_priv {
> struct led_pwm_data leds[0];
> };
>
> -static void __led_pwm_set(struct led_pwm_data *led_dat)
> -{
> - int new_duty = led_dat->duty;
> -
> - pwm_config(led_dat->pwm, new_duty, led_dat->period);
> -
> - if (new_duty == 0)
> - pwm_disable(led_dat->pwm);
> - else
> - pwm_enable(led_dat->pwm);
> -}
> -
> static int led_pwm_set(struct led_classdev *led_cdev,
> enum led_brightness brightness)
> {
> struct led_pwm_data *led_dat =
> container_of(led_cdev, struct led_pwm_data, cdev);
> unsigned int max = led_dat->cdev.max_brightness;
> - unsigned long long duty = led_dat->period;
> + unsigned long long duty = led_dat->pwmstate.period;
>
> duty *= brightness;
> do_div(duty, max);
>
> if (led_dat->active_low)
> - duty = led_dat->period - duty;
> -
> - led_dat->duty = duty;
> -
> - __led_pwm_set(led_dat);
> + duty = led_dat->pwmstate.period - duty;
>
> - return 0;
> + led_dat->pwmstate.duty_cycle = duty;
> + led_dat->pwmstate.enabled = duty > 0;
> + return pwm_apply_state(led_dat->pwm, &led_dat->pwmstate);
> }
>
> static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
> struct led_pwm *led, struct fwnode_handle *fwnode)
> {
> struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
> - struct pwm_args pargs;
> int ret;
>
> led_data->active_low = led->active_low;
> @@ -93,17 +77,10 @@ static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
>
> led_data->cdev.brightness_set_blocking = led_pwm_set;
>
> - /*
> - * FIXME: pwm_apply_args() should be removed when switching to the
> - * atomic PWM API.
> - */
> - pwm_apply_args(led_data->pwm);
> -
> - pwm_get_args(led_data->pwm, &pargs);
> + pwm_init_state(led_data->pwm, &led_data->pwmstate);
>
> - led_data->period = pargs.period;
> - if (!led_data->period)
> - led_data->period = led->pwm_period_ns;
> + if (!led_data->pwmstate.period)
> + led_data->pwmstate.period = led->pwm_period_ns;
>
> ret = devm_led_classdev_register(dev, &led_data->cdev);
> if (ret == 0) {
> --
> 2.24.0
>
Using the same setup described in my response to patch [1/3], I checked
the following:
* LED appears as expected with brightness continuously swept between 0
and 255 at fixed intervals
* I2C traffic appears as expected for random cases of brightness being
changed between 0 and !0 and back to 0
And so:
Tested-by: Jeff LaBundy <jeff@xxxxxxxxxxx>
Kind regards,
Jeff LaBundy
