Re: [PATCH] i2c: designware: Round down ACPI provided clk to nearest supported clk

[Hans de Goede <hdegoede@xxxxxxxxxx>]

Hi,

On 08/29/2017 10:18 PM, Wolfram Sang wrote:
> Hi,
>
> > > I dunno what standard says if we may or may not use 100 kHz as a last
> > > resort even for speeds defined less than 100 kHz.
> >
> > The < 100000 case is for when i2c_acpi_find_bus_speed() returns 0, so
> > that we then keep it 0, in which case the code a bit lower will pick
> > a default.
>
> This is fine by me.
>
> > Since speeds < 100000 are clearly not valid treating them
>
> Here I wonder: Not valid because of ACPI specs? Because I2C specs surely
> allow speeds < 100kHz.

The speed comes from an ACPI entry describing an i2c client,
any compliant i2c client must at least support 100KHz, right ?

Alternatively I could wrap the entire round-down for loop in
an if (acpi_speed) {} block.

Regards,

Hans