Commit d81738b7 authored by Lee Jones's avatar Lee Jones Committed by Thierry Reding
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pwm: sti: Only request clock rate when needed 



In the original code the clock rate was only obtained during
initialisation; however, the rate may change between then and
its use.  This patch ensures the correct rate is acquired just
before use.

Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
parent c5f94ae6

drivers/pwm/pwm-sti.c

+8 −8
Original line number Original line Diff line number Diff line
@@ -51,7 +51,6 @@ struct sti_pwm_compat_data { 




struct sti_pwm_chip {

struct sti_pwm_chip {

	struct device *dev;

	struct device *dev;

	unsigned long clk_rate;

	struct clk *pwm_clk;

	struct clk *pwm_clk;

	struct regmap *regmap;

	struct regmap *regmap;

	struct sti_pwm_compat_data *cdata;

	struct sti_pwm_compat_data *cdata;
@@ -86,13 +85,20 @@ static int sti_pwm_get_prescale(struct sti_pwm_chip *pc, unsigned long period, 
				unsigned int *prescale)

				unsigned int *prescale)

{

{

	struct sti_pwm_compat_data *cdata = pc->cdata;

	struct sti_pwm_compat_data *cdata = pc->cdata;

	unsigned long clk_rate;

	unsigned long val;

	unsigned long val;

	unsigned int ps;

	unsigned int ps;





	clk_rate = clk_get_rate(pc->pwm_clk);

	if (!clk_rate) {

		dev_err(pc->dev, "failed to get clock rate\n");

		return -EINVAL;

	}



	/*

	/*

	 * prescale = ((period_ns * clk_rate) / (10^9 * (max_pwm_count + 1)) - 1

	 * prescale = ((period_ns * clk_rate) / (10^9 * (max_pwm_count + 1)) - 1

	 */

	 */

	val = NSEC_PER_SEC / pc->clk_rate;

	val = NSEC_PER_SEC / clk_rate;

	val *= cdata->max_pwm_cnt + 1;

	val *= cdata->max_pwm_cnt + 1;





	if (period % val) {

	if (period % val) {
@@ -353,12 +359,6 @@ static int sti_pwm_probe(struct platform_device *pdev) 
		return PTR_ERR(pc->pwm_clk);

		return PTR_ERR(pc->pwm_clk);

	}

	}





	pc->clk_rate = clk_get_rate(pc->pwm_clk);

	if (!pc->clk_rate) {

		dev_err(dev, "failed to get clock rate\n");

		return -EINVAL;

	}



	ret = clk_prepare(pc->pwm_clk);

	ret = clk_prepare(pc->pwm_clk);

	if (ret) {

	if (ret) {

		dev_err(dev, "failed to prepare clock\n");

		dev_err(dev, "failed to prepare clock\n");