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    Subject[RESEND PATCH v5 1/4] devfreq: exynos-bus: correct clock enable sequence
    Date
    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>
    ---
    Changes:
    v5:
    - added Acked-by tag
    v4:
    - move regulator disable after clock disable
    - remove unrelated changes
    - add disabling regulators in error path in exynos_bus_probe()

    ---
    drivers/devfreq/exynos-bus.c | 31 +++++++++++++++++--------------
    1 file changed, 17 insertions(+), 14 deletions(-)

    diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
    index 486cc5b422f1..f34fa26f00d0 100644
    --- 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 @@ static int exynos_bus_probe(struct platform_device *pdev)
    err:
    dev_pm_opp_of_remove_table(dev);
    clk_disable_unprepare(bus->clk);
    +err_reg:
    + if (!passive)
    + regulator_disable(bus->regulator);

    return ret;
    }
    --
    2.22.0
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