[PATCH v4] i2c: designware-platdrv: fix unbalanced clk enable and prepare

Jisheng Zhang
2016-04-22T08:53:43Z

If i2c_dw_probe() fails, we should disable and unprepare the clock,
otherwise the clock enable and prepare is left unbalanced.

In dw_i2c_plat_remove(), we'd better to not rely on runtime PM to
disable and unprepare the clock since CONFIG_PM may be disabled when
configuring the kernel. So we explicitly disable and unprepare the
clock in dw_i2c_plat_remove() rather than implicitly rely on
pm_runtime_put_sync(). To keep the device usage count balanced, we
call pm_runtime_put_noidle() to decrease the usage count.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
---
Since v3:
- use runtime PM rather than rpm in commit msg
- remove duplicated "(" in commit msg

Since v2:
- s/clk/clock
- describe why use pm_runtime_put_noidle()

Since v1:
- fix commit msg: "not rely on rpm" rather than "rely on rpm"
- call i2c_dw_plat_prepare_clk after pm_rumtime_disable()
drivers/i2c/busses/i2c-designware-platdrv.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index d656657..a771781 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -253,8 +253,11 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
}

r = i2c_dw_probe(dev);
- if (r && !dev->pm_runtime_disabled)
- pm_runtime_disable(&pdev->dev);
+ if (r) {
+ if (!dev->pm_runtime_disabled)
+ pm_runtime_disable(&pdev->dev);
+ i2c_dw_plat_prepare_clk(dev, false);
+ }

return r;
}
@@ -264,15 +267,16 @@ static int dw_i2c_plat_remove(struct platform_device *pdev)
struct dw_i2c_dev *dev = platform_get_drvdata(pdev);

pm_runtime_get_sync(&pdev->dev);
+ pm_runtime_dont_use_autosuspend(&pdev->dev);
+ if (!dev->pm_runtime_disabled)
+ pm_runtime_disable(&pdev->dev);
+ pm_runtime_put_noidle(&pdev->dev);

i2c_del_adapter(&dev->adapter);

i2c_dw_disable(dev);

- pm_runtime_dont_use_autosuspend(&pdev->dev);
- pm_runtime_put_sync(&pdev->dev);
- if (!dev->pm_runtime_disabled)
- pm_runtime_disable(&pdev->dev);
+ i2c_dw_plat_prepare_clk(dev, false);

return 0;
}
--
2.8.1