[PATCH AUTOSEL 5.3 122/203] PM / devfreq: exynos-bus: Correct clock enable sequence

Sasha Levin
2019-09-22T18:47:29Z

From: Kamil Konieczny <k.konieczny@partner.samsung.com>

[ 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>
---
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 d9f377912c104..7c06df8bd74fe 100644
--- a/drivers/devfreq/exynos-bus.c
+++ b/drivers/devfreq/exynos-bus.c
@@ -191,11 +191,10 @@ 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);
}

/*
@@ -383,6 +382,7 @@ 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");
@@ -396,27 +396,27 @@ 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;
@@ -507,6 +507,9 @@ 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;
}
--
2.20.1