Re: [PATCH 2/2] i2c designware add support of I2C standard mode

From: Wolfram Sang
Date: Thu Jan 16 2014 - 14:34:32 EST


On Tue, Oct 08, 2013 at 05:00:55PM +0200, Romain Baeriswyl wrote:
> Some legacy devices support ony I2C standard mode at 100kHz.
> This patch allows to select the standard mode through the DTS
> with the use of the existing clock-frequency parameter.
>
> When clock-frequency parameter is not set, the fast mode is selected.
> Only when the parameter is set at 100000, the standard mode is selected.
>
> Signed-off-by: Romain Baeriswyl <romainba@xxxxxxxxxx>
> Reviewed-by: Christian Ruppert <christian.ruppert@xxxxxxxxxx>

Pretty much OK. One change needed, though:

> ---
> .../devicetree/bindings/i2c/i2c-designware.txt | 1 +
> drivers/i2c/busses/i2c-designware-platdrv.c | 17 +++++++++++++++--
> 2 files changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> index 5199b0c..16d0bef 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> @@ -9,6 +9,7 @@ Required properties :
> Recommended properties :
>
> - clock-frequency : desired I2C bus clock frequency in Hz.
> + Only standard mode at 100kHz and fast mode at 400kHz are supported.

This should not go the bindings doc, since this is a linux specific
detail. It should go...

> + if (clk_freq != 100000 && clk_freq != 400000)
> + return -EINVAL;

... here as an dev_err message "Only x and y supported".

Rest looks good, thanks!

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