# Re: \[PATCH 2/3\] i2c-mpc: add support for the MPC512x processors from Freescale

- From: Wolfgang Grandegger \<hidden\>
- Date: 2010-01-26 18:44:57 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2010/01/8050397
- Thread: https://ratatoskr.run/linux-devicetree/2010/01/8050397/t.md

```text
Ben Dooks wrote:
> On Mon, Jan 25, 2010 at 04:15:09PM +0100, Wolfram Sang wrote:
>>>>>  
>>>>> -static void __devinit mpc_i2c_setclock_52xx(struct device_node *node,
>>>>> -					    struct mpc_i2c *i2c,
>>>>> -					    u32 clock, u32 prescaler)
>>>>> +static void __devinit mpc_i2c_setup_52xx(struct device_node *node,
>>>>> +					 struct mpc_i2c *i2c,
>>>>> +					 u32 clock, u32 prescaler)
>>>>>  {
>>>>>  	int ret, fdr;
>>>>>  
>>>>> +	if (clock == -1) {
>>>> Could we use 0 for 'no_clock'? This would make the above statement simply
>>> "0" is already used to maintain backward compatibility setting a safe
>>> divider.
>> Ah, now I see:
>>
>> 'clock == -1' means 'preserve clocks' (and is checked here in mpc_i2c_setup_52xx())
>> 'clock ==  0' means 'safe divider' (and is checked in mpc_i2c_get_fdr_52xx())
> 
> hmm, sounds like a job for a  #define or similar.

See v2 of this patch.

Wolfgang.
```