diff options
Diffstat (limited to 'drivers/pwm/pwm-lpss.c')
| -rw-r--r-- | drivers/pwm/pwm-lpss.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c index 723ca9de8325..ea93ef9f3672 100644 --- a/drivers/pwm/pwm-lpss.c +++ b/drivers/pwm/pwm-lpss.c @@ -159,8 +159,42 @@ static int pwm_lpss_apply(struct pwm_chip *chip, struct pwm_device *pwm, return 0; } +/* This function gets called once from pwmchip_add to get the initial state */ +static void pwm_lpss_get_state(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_state *state) +{ + struct pwm_lpss_chip *lpwm = to_lpwm(chip); + unsigned long base_unit_range; + unsigned long long base_unit, freq, on_time_div; + u32 ctrl; + + base_unit_range = BIT(lpwm->info->base_unit_bits); + + ctrl = pwm_lpss_read(pwm); + on_time_div = 255 - (ctrl & PWM_ON_TIME_DIV_MASK); + base_unit = (ctrl >> PWM_BASE_UNIT_SHIFT) & (base_unit_range - 1); + + freq = base_unit * lpwm->info->clk_rate; + do_div(freq, base_unit_range); + if (freq == 0) + state->period = NSEC_PER_SEC; + else + state->period = NSEC_PER_SEC / (unsigned long)freq; + + on_time_div *= state->period; + do_div(on_time_div, 255); + state->duty_cycle = on_time_div; + + state->polarity = PWM_POLARITY_NORMAL; + state->enabled = !!(ctrl & PWM_ENABLE); + + if (state->enabled) + pm_runtime_get(chip->dev); +} + static const struct pwm_ops pwm_lpss_ops = { .apply = pwm_lpss_apply, + .get_state = pwm_lpss_get_state, .owner = THIS_MODULE, }; |