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pwm: sti: Only request clock rate when needed

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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: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Lee Jones 2016-08-16 10:35:00 +01:00 committed by Thierry Reding
parent c5f94ae639
commit d81738b76f
1 changed files with 8 additions and 8 deletions
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16
drivers/pwm/pwm-sti.c
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@ -51,7 +51,6 @@ struct sti_pwm_compat_data {
struct sti_pwm_chip {
struct device *dev;
unsigned long clk_rate;
struct clk *pwm_clk;
struct regmap *regmap;
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)
{
struct sti_pwm_compat_data *cdata = pc->cdata;
unsigned long clk_rate;
unsigned long val;
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
*/
val = NSEC_PER_SEC / pc->clk_rate;
val = NSEC_PER_SEC / clk_rate;
val *= cdata->max_pwm_cnt + 1;
if (period % val) {
@ -353,12 +359,6 @@ static int sti_pwm_probe(struct platform_device *pdev)
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);
if (ret) {
dev_err(dev, "failed to prepare clock\n");