Re: [PATCH v5 2/2] i2c: rk3x: add i2c support for rk3399 soc

David.Wu
2016-04-18T13:15:46Z

Hi Wolfram，

在 2016/4/16 1:58, Wolfram Sang 写道:
>> The default frequency rate of function clock is 50M Hz, it can match
>> F/S mode, but HS mode not. If use default rate 50M to get 1.7M
>> scl-frequency rate , we could not get accurately 1.7M frequecy rate.
>> The input-clk-rate is more higher, we get more accurately
>> scl-frequency rate, as 200M is a suitable input-clk-rate.
>>
>> If 200M was used for F/S mode, it would increase power consumption, so
>> add a option that could be configured from DT.
> If I understand you correctly, couldn't you use clk_set_rate() depending
> on the desired scl frequency which is already described in DT as
> clock-frequency?

Yeap, the default input clock rate is too low for HS mode, and it 's
flexible that
we get it from DT.