PM / devfreq: tegra: Don't ignore clk errors

The clk_set_min_rate() could fail and in this case clk_set_rate() sets
rate to 0, which may drop EMC rate to minimum and make machine very
difficult to use.

Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>

diff --git a/drivers/devfreq/tegra-devfreq.c b/drivers/devfreq/tegra-devfreq.c
index 986f3df..325443f 100644 (file)
--- a/drivers/devfreq/tegra-devfreq.c
+++ b/drivers/devfreq/tegra-devfreq.c
@@ -472,8 +472,10 @@ static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
                                u32 flags)
 {
        struct tegra_devfreq *tegra = dev_get_drvdata(dev);
+       struct devfreq *devfreq = tegra->devfreq;
        struct dev_pm_opp *opp;
        unsigned long rate;
+       int err;
 
        opp = devfreq_recommended_opp(dev, freq, flags);
        if (IS_ERR(opp)) {
@@ -483,10 +485,20 @@ static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
        rate = dev_pm_opp_get_freq(opp);
        dev_pm_opp_put(opp);
 
-       clk_set_min_rate(tegra->emc_clock, rate);
-       clk_set_rate(tegra->emc_clock, 0);
+       err = clk_set_min_rate(tegra->emc_clock, rate);
+       if (err)
+               return err;
+
+       err = clk_set_rate(tegra->emc_clock, 0);
+       if (err)
+               goto restore_min_rate;
 
        return 0;
+
+restore_min_rate:
+       clk_set_min_rate(tegra->emc_clock, devfreq->previous_freq);
+
+       return err;
 }
 
 static int tegra_devfreq_get_dev_status(struct device *dev,