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Commit 3aacd3e1 authored by Ajit Pal Singh's avatar Ajit Pal Singh Committed by Thierry Reding
Browse files

pwm: sti: Remove PWM period table 



Removes the PWM period table. Instead the prescaler is computed
from the period value passed in the config() function.

Signed-off-by: default avatarAjit Pal Singh <ajitpal.singh@st.com>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
parent 6ad6b838

drivers/pwm/pwm-sti.c

+16 −48
Original line number Diff line number Diff line
@@ -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;