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

Andy Shevchenko
2017-07-08T14:03:37Z

On Sat, 2017-07-08 at 15:10 +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>
> ---
>  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 d5acaf8d65bf..c6f5a41d72b5 100644
> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> @@ -254,6 +254,9 @@ 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;

I would rather convert to choose closest one, though I am not sure at
all which approach would be better in long term.

>   /*
>    * 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