diff options
Diffstat (limited to 'drivers/pwm/pwm-lpss.c')
| -rw-r--r-- | drivers/pwm/pwm-lpss.c | 26 |
1 files changed, 14 insertions, 12 deletions
diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c index 295b963dbddb..72c0bce5a75c 100644 --- a/drivers/pwm/pwm-lpss.c +++ b/drivers/pwm/pwm-lpss.c @@ -27,7 +27,6 @@ #define PWM_SW_UPDATE BIT(30) #define PWM_BASE_UNIT_SHIFT 8 #define PWM_ON_TIME_DIV_MASK 0x000000ff -#define PWM_DIVISION_CORRECTION 0x2 /* Size of each PWM register space if multiple */ #define PWM_SIZE 0x400 @@ -92,8 +91,8 @@ static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm, int duty_ns, int period_ns) { struct pwm_lpss_chip *lpwm = to_lpwm(chip); - u8 on_time_div; - unsigned long c, base_unit_range; + unsigned long long on_time_div; + unsigned long c = lpwm->info->clk_rate, base_unit_range; unsigned long long base_unit, freq = NSEC_PER_SEC; u32 ctrl; @@ -101,21 +100,18 @@ static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm, /* * The equation is: - * base_unit = ((freq / c) * base_unit_range) + correction + * base_unit = round(base_unit_range * freq / c) */ base_unit_range = BIT(lpwm->info->base_unit_bits); - base_unit = freq * base_unit_range; + freq *= base_unit_range; - c = lpwm->info->clk_rate; - if (!c) - return -EINVAL; - - do_div(base_unit, c); - base_unit += PWM_DIVISION_CORRECTION; + base_unit = DIV_ROUND_CLOSEST_ULL(freq, c); if (duty_ns <= 0) duty_ns = 1; - on_time_div = 255 - (255 * duty_ns / period_ns); + on_time_div = 255ULL * duty_ns; + do_div(on_time_div, period_ns); + on_time_div = 255ULL - on_time_div; pm_runtime_get_sync(chip->dev); @@ -169,6 +165,7 @@ struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev, struct resource *r, const struct pwm_lpss_boardinfo *info) { struct pwm_lpss_chip *lpwm; + unsigned long c; int ret; lpwm = devm_kzalloc(dev, sizeof(*lpwm), GFP_KERNEL); @@ -180,6 +177,11 @@ struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev, struct resource *r, return ERR_CAST(lpwm->regs); lpwm->info = info; + + c = lpwm->info->clk_rate; + if (!c) + return ERR_PTR(-EINVAL); + lpwm->chip.dev = dev; lpwm->chip.ops = &pwm_lpss_ops; lpwm->chip.base = -1; |