Re: [PATCH v3 2/2] i2c: designware: Some broken DSTDs use 1MiHz instead of 1MHz

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 16-07-17 16:04, Andy Shevchenko wrote:
> On Thu, 2017-07-13 at 15:45 +0200, Hans de Goede wrote:
>> At least the Acer Iconia Tab8 / aka W1-810 uses 1MiHz instead of
>> 1MHz for one of its busses, fix this up to 1MHz instead of failing
>> the probe of that bus.
>>
>> This fixes the accelerometer on the Acer Iconia Tab8 not working.
>>
> 
> Should it have a Fixes tag?

No I don't think so, as this worksaround a firmware bug the original
commit introducing the check is not really fixed by this, as the
original commit is fine really.

Regards,

Hans



> 
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> 
> (on condition Jarkko and Wolfram are okay with this; in the future it
> would be better to have a list of possible speeds and algo that chooses
> one based on FW configuration)
> 
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>> ---
>>   drivers/i2c/busses/i2c-designware-platdrv.c | 3 +++
>>   1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c
>> b/drivers/i2c/busses/i2c-designware-platdrv.c
>> index d139b156f9c9..143a8fd582b4 100644
>> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
>> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
>> @@ -298,6 +298,9 @@ static int dw_i2c_plat_probe(struct
>> platform_device *pdev)
>>   	}
>>   
>>   	acpi_speed = i2c_acpi_find_bus_speed(&pdev->dev);
>> +	/* Some broken DSTDs use 1MiHz instead of 1MHz */
>> +	if (acpi_speed == 1048576)
>> +		acpi_speed = 1000000;
>>   	/*
>>   	 * Find bus speed from the "clock-frequency" device property,
>> ACPI
>>   	 * or by using fast mode if neither is set.
>