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

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

[Hans de Goede]

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.

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.
-- 
2.13.0

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

[Andy Shevchenko]

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?

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.

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy

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

[Hans de Goede]

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.
> 

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

[Wolfram Sang]

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> (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)

In deed, that sounds feasible if more broken firmware shows up.


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

[Wolfram Sang]

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On Thu, Jul 13, 2017 at 03:45:02PM +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.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Applied to for-current, thanks!


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