diff options
Diffstat (limited to 'drivers/pwm')
| -rw-r--r-- | drivers/pwm/pwm-sti.c | 64 |
1 files changed, 16 insertions, 48 deletions
diff --git a/drivers/pwm/pwm-sti.c b/drivers/pwm/pwm-sti.c index f98afe4906f..b95115cdaea 100644 --- a/drivers/pwm/pwm-sti.c +++ b/drivers/pwm/pwm-sti.c @@ -10,7 +10,6 @@ * (at your option) any later version. */ -#include <linux/bsearch.h> #include <linux/clk.h> #include <linux/math64.h> #include <linux/mfd/syscon.h> @@ -56,7 +55,6 @@ struct sti_pwm_chip { struct regmap_field *prescale_high; struct regmap_field *pwm_en; struct regmap_field *pwm_int_en; - unsigned long *pwm_periods; struct pwm_chip chip; struct pwm_device *cur; unsigned int en_count; @@ -77,29 +75,31 @@ static inline struct sti_pwm_chip *to_sti_pwmchip(struct pwm_chip *chip) } /* - * Calculate the period values supported by the PWM for the - * current clock rate. + * Calculate the prescaler value corresponding to the period. */ -static void sti_pwm_calc_periods(struct sti_pwm_chip *pc) +static int sti_pwm_get_prescale(struct sti_pwm_chip *pc, unsigned long period, + unsigned int *prescale) { struct sti_pwm_compat_data *cdata = pc->cdata; - struct device *dev = pc->dev; unsigned long val; - int i; + unsigned int ps; /* - * period_ns = (10^9 * (prescaler + 1) * (MAX_PWM_COUNT + 1)) / CLK_RATE + * prescale = ((period_ns * clk_rate) / (10^9 * (max_pwm_count + 1)) - 1 */ val = NSEC_PER_SEC / pc->clk_rate; val *= cdata->max_pwm_cnt + 1; - dev_dbg(dev, "possible periods for clkrate[HZ]:%lu\n", pc->clk_rate); - - for (i = 0; i <= cdata->max_prescale; i++) { - pc->pwm_periods[i] = val * (i + 1); - dev_dbg(dev, "prescale:%d, period[ns]:%lu\n", - i, pc->pwm_periods[i]); + if (period % val) { + return -EINVAL; + } else { + ps = period / val - 1; + if (ps > cdata->max_prescale) + return -EINVAL; } + *prescale = ps; + + return 0; } /* Calculate the number of PWM devices configured with a period. */ @@ -120,17 +120,6 @@ static unsigned int sti_pwm_count_configured(struct pwm_chip *chip) return ncfg; } -static int sti_pwm_cmp_periods(const void *key, const void *elt) -{ - unsigned long i = *(unsigned long *)key; - unsigned long j = *(unsigned long *)elt; - - if (i < j) - return -1; - else - return i == j ? 0 : 1; -} - /* * For STiH4xx PWM IP, the PWM period is fixed to 256 local clock cycles. * The only way to change the period (apart from changing the PWM input clock) @@ -148,7 +137,6 @@ static int sti_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_device *cur = pc->cur; struct device *dev = pc->dev; unsigned int prescale = 0, pwmvalx; - unsigned long *found; int ret; unsigned int ncfg; bool period_same = false; @@ -178,21 +166,9 @@ static int sti_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, return ret; if (!period_same) { - /* - * Search for matching period value. - * The corresponding index is our prescale value. - */ - found = bsearch(&period_ns, &pc->pwm_periods[0], - cdata->max_prescale + 1, - sizeof(unsigned long), - sti_pwm_cmp_periods); - if (!found) { - dev_err(dev, - "failed to find matching period\n"); - ret = -EINVAL; + ret = sti_pwm_get_prescale(pc, period_ns, &prescale); + if (ret) goto clk_dis; - } - prescale = found - &pc->pwm_periods[0]; ret = regmap_field_write(pc->prescale_low, @@ -373,12 +349,6 @@ static int sti_pwm_probe(struct platform_device *pdev) if (ret) return ret; - pc->pwm_periods = devm_kzalloc(dev, - sizeof(unsigned long) * (pc->cdata->max_prescale + 1), - GFP_KERNEL); - if (!pc->pwm_periods) - return -ENOMEM; - pc->clk = of_clk_get_by_name(dev->of_node, "pwm"); if (IS_ERR(pc->clk)) { dev_err(dev, "failed to get PWM clock\n"); @@ -397,8 +367,6 @@ static int sti_pwm_probe(struct platform_device *pdev) return ret; } - sti_pwm_calc_periods(pc); - pc->chip.dev = dev; pc->chip.ops = &sti_pwm_ops; pc->chip.base = -1; |