[PATCH 02/10] i2c: designware-platdrv: Gate clk in error path in ->probe()

[Ulf Hansson]

On 14 June 2016 at 17:22, Andy Shevchenko
<andriy.shevchenko at linux.intel.com> wrote:
> On Tue, 2016-06-14 at 17:07 +0200, Ulf Hansson wrote:
>> The call to i2c_dw_probe() may fail in ->probe() in which case the
>> clock
>> remains ungated. Fix the error path by gating the clock before the
>> error
>> code is returned.
>>
>> Signed-off-by: Ulf Hansson <ulf.hansson at linaro.org>
>> ---
>>  drivers/i2c/busses/i2c-designware-platdrv.c | 10 ++++++++--
>>  1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c
>> b/drivers/i2c/busses/i2c-designware-platdrv.c
>> index e39962b..19174e7 100644
>> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
>> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
>> @@ -235,6 +235,7 @@ static int dw_i2c_plat_probe(struct
>> platform_device *pdev)
>>       ACPI_COMPANION_SET(&adap->dev, ACPI_COMPANION(&pdev->dev));
>>       adap->dev.of_node = pdev->dev.of_node;
>>
>
>
>> +     pm_runtime_get_noresume(&pdev->dev);
>
>> +     pm_runtime_put(&pdev->dev);
>
> I don't see an explanation of these add-ons.

As we explicitly do clk_disable_unprepare() in the error path, we must
prevent the ->runtime_suspend() callback to be called during this
period.

This is a common pattern used by many drivers deploying runtime PM
support, which is probably why I left out the explanation.

I can update the change log with this information, if you like.

Kind regards
Uffe