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: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

diff --git a/drivers/pwm/pwm-sti.c b/drivers/pwm/pwm-sti.c
index 388f2aa285aed2aec3f8bf4bf127eb99901cf3b6..da0c1bf2a7054dcc115fd89316c10c5b0cd24aea 100644 (file)
--- a/drivers/pwm/pwm-sti.c
+++ b/drivers/pwm/pwm-sti.c
@@ -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");