From mboxrd@z Thu Jan  1 00:00:00 1970
From: Hans de Goede <hdegoede@redhat.com>
Subject: Re: [PATCH] i2c: designware: Round down ACPI provided clk to nearest
 supported clk
Date: Tue, 29 Aug 2017 22:27:14 +0200
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To: Wolfram Sang <wsa@the-dreams.de>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>, Jarkko Nikula <jarkko.nikula@linux.intel.com>, linux-i2c@vger.kernel.org

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