Hi, On Mon, Mar 03, 2025 at 06:14:36PM +0200, Abel Vesa wrote: > Currently, the implementation computes the best matched period based > on the requested one, by looping through all possible register > configurations. The best matched period is below the requested period. > This means the PWM consumer could request duty cycle values between > the best matched period and the requested period, which with the current > implementation for computing the PWM value, it will result in values out > of range with respect to the selected resolution. > > So change the way the PWM value is determined as a ratio between the > requested period and duty cycle, mapped on the resolution interval. > Do this in contrast to using the register configuration selected when > the best matching period was determined. > > Signed-off-by: Abel Vesa <abel.vesa@xxxxxxxxxx> > --- > This patch is based on the following patchset: > https://lore.kernel.org/all/20250303-leds-qcom-lpg-fix-max-pwm-on-hi-res-v3-0-62703c0ab76a@xxxxxxxxxx/ > --- Tested-by: Sebastian Reichel <sre@xxxxxxxxxx> Greetings, -- Sebastian > drivers/leds/rgb/leds-qcom-lpg.c | 16 ++++++++++------ > 1 file changed, 10 insertions(+), 6 deletions(-) > > diff --git a/drivers/leds/rgb/leds-qcom-lpg.c b/drivers/leds/rgb/leds-qcom-lpg.c > index 4f2a178e3d265a2cc88e651d3e2ca6ae3dfac2e2..80130c205dce7c6ae1c356b7a7c5f6460a2b0bb0 100644 > --- a/drivers/leds/rgb/leds-qcom-lpg.c > +++ b/drivers/leds/rgb/leds-qcom-lpg.c > @@ -523,8 +523,10 @@ static int lpg_calc_freq(struct lpg_channel *chan, uint64_t period) > return 0; > } > > -static void lpg_calc_duty(struct lpg_channel *chan, uint64_t duty) > +static void lpg_calc_duty(struct lpg_channel *chan, uint64_t duty, uint64_t period) > { > + const unsigned int *pwm_resolution_arr; > + unsigned int step; > unsigned int max; > unsigned int val; > unsigned int clk_rate; > @@ -532,13 +534,15 @@ static void lpg_calc_duty(struct lpg_channel *chan, uint64_t duty) > if (chan->subtype == LPG_SUBTYPE_HI_RES_PWM) { > max = BIT(lpg_pwm_resolution_hi_res[chan->pwm_resolution_sel]) - 1; > clk_rate = lpg_clk_rates_hi_res[chan->clk_sel]; > + pwm_resolution_arr = lpg_pwm_resolution_hi_res; > } else { > max = BIT(lpg_pwm_resolution[chan->pwm_resolution_sel]) - 1; > clk_rate = lpg_clk_rates[chan->clk_sel]; > + pwm_resolution_arr = lpg_pwm_resolution; > } > > - val = div64_u64(duty * clk_rate, > - (u64)NSEC_PER_SEC * lpg_pre_divs[chan->pre_div_sel] * (1 << chan->pre_div_exp)); > + step = div64_u64(period, max); > + val = div64_u64(duty, step); > > chan->pwm_value = min(val, max); > } > @@ -829,7 +833,7 @@ static void lpg_brightness_set(struct lpg_led *led, struct led_classdev *cdev, > lpg_calc_freq(chan, NSEC_PER_MSEC); > > duty = div_u64(brightness * chan->period, cdev->max_brightness); > - lpg_calc_duty(chan, duty); > + lpg_calc_duty(chan, duty, NSEC_PER_MSEC); > chan->enabled = true; > chan->ramp_enabled = false; > > @@ -906,7 +910,7 @@ static int lpg_blink_set(struct lpg_led *led, > chan = led->channels[i]; > > lpg_calc_freq(chan, period); > - lpg_calc_duty(chan, duty); > + lpg_calc_duty(chan, duty, period); > > chan->enabled = true; > chan->ramp_enabled = false; > @@ -1241,7 +1245,7 @@ static int lpg_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, > if (ret < 0) > goto out_unlock; > > - lpg_calc_duty(chan, state->duty_cycle); > + lpg_calc_duty(chan, state->duty_cycle, state->period); > } > chan->enabled = state->enabled; > > > --- > base-commit: 0067a4b21c9ab441bbe6bf3635b3ddd21f6ca7c3 > change-id: 20250303-leds-qcom-lpg-compute-pwm-value-using-period-0823ceb7542a > > Best regards, > -- > Abel Vesa <abel.vesa@xxxxxxxxxx> >
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