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

David.Wu
2016-04-15T12:10:16Z

Hi Wolfram,

在 2016/4/15 2:48, Wolfram Sang 写道:
>> + - input-clk-rate : frequency rate of function clock used(in Hz). If omitted,
>> + the default clock rate is used. It is just used at rk3399 soc.
> Why is this needed? Why don't we simply use the default or calculate the
> best value somehow?
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.

>> + * @t_calc: Caculated rk3x private timings that would
>> + * be written into regs
> double space
>