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

Dmitry Osipenko
2019-05-01T23:41:55Z

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>
---
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