PM / devfreq: exynos-bus: Correct clock enable sequence

[ Upstream commit 2c2b20e0da89c76759ee28c6824413ab2fa3bfc6 ]

Regulators should be enabled before clocks to avoid h/w hang. This
require change in exynos_bus_probe() to move exynos_bus_parse_of()
after exynos_bus_parent_parse_of() and change in error handling.
Similar change is needed in exynos_bus_exit() where clock should be
disabled before regulators.

Signed-off-by: Kamil Konieczny <k.konieczny@partner.samsung.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
index c25658b..24a9658 100644 (file)
--- a/drivers/devfreq/exynos-bus.c
+++ b/drivers/devfreq/exynos-bus.c
@@ -194,11 +194,10 @@ static void exynos_bus_exit(struct device *dev)
        if (ret < 0)
                dev_warn(dev, "failed to disable the devfreq-event devices\n");
 
-       if (bus->regulator)
-               regulator_disable(bus->regulator);
-
        dev_pm_opp_of_remove_table(dev);
        clk_disable_unprepare(bus->clk);
+       if (bus->regulator)
+               regulator_disable(bus->regulator);
 }
 
 /*
@@ -386,6 +385,7 @@ static int exynos_bus_probe(struct platform_device *pdev)
        struct exynos_bus *bus;
        int ret, max_state;
        unsigned long min_freq, max_freq;
+       bool passive = false;
 
        if (!np) {
                dev_err(dev, "failed to find devicetree node\n");
@@ -399,27 +399,27 @@ static int exynos_bus_probe(struct platform_device *pdev)
        bus->dev = &pdev->dev;
        platform_set_drvdata(pdev, bus);
 
-       /* Parse the device-tree to get the resource information */
-       ret = exynos_bus_parse_of(np, bus);
-       if (ret < 0)
-               return ret;
-
        profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL);
-       if (!profile) {
-               ret = -ENOMEM;
-               goto err;
-       }
+       if (!profile)
+               return -ENOMEM;
 
        node = of_parse_phandle(dev->of_node, "devfreq", 0);
        if (node) {
                of_node_put(node);
-               goto passive;
+               passive = true;
        } else {
                ret = exynos_bus_parent_parse_of(np, bus);
+               if (ret < 0)
+                       return ret;
        }
 
+       /* Parse the device-tree to get the resource information */
+       ret = exynos_bus_parse_of(np, bus);
        if (ret < 0)
-               goto err;
+               goto err_reg;
+
+       if (passive)
+               goto passive;
 
        /* Initialize the struct profile and governor data for parent device */
        profile->polling_ms = 50;
@@ -510,6 +510,9 @@ out:
 err:
        dev_pm_opp_of_remove_table(dev);
        clk_disable_unprepare(bus->clk);
+err_reg:
+       if (!passive)
+               regulator_disable(bus->regulator);
 
        return ret;
 }