[PATCH v4 04/16] PM / devfreq: tegra: Don't ignore clk errors

[Dmitry Osipenko]

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@xxxxxxxxxxx>
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
 drivers/devfreq/tegra-devfreq.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/devfreq/tegra-devfreq.c b/drivers/devfreq/tegra-devfreq.c
index 7d7b9a5895b2..c7428c5eee23 100644
--- a/drivers/devfreq/tegra-devfreq.c
+++ b/drivers/devfreq/tegra-devfreq.c
@@ -484,8 +484,10 @@ 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)) {
@@ -495,10 +497,20 @@ 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,
-- 
2.21.0