Re: [PATCH 08/14] OMAPDSS: DSS: add new clock calculation code

[Tomi Valkeinen <tomi.valkeinen@ti.com>]

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On 2013-03-20 17:17, Archit Taneja wrote:
> On Friday 08 March 2013 05:22 PM, Tomi Valkeinen wrote:
>> Add new way to iterate over DSS clock divisors. dss_div_calc() provides
>> a generic way to go over all the divisors, within given clock range.
>> dss_div_calc() will call a callback function for each divider set,
>> making the function reusable for all use cases.
>>
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
>> ---
>>   drivers/video/omap2/dss/dss.c |   36
>> ++++++++++++++++++++++++++++++++++++
>>   drivers/video/omap2/dss/dss.h |    3 +++
>>   2 files changed, 39 insertions(+)
>>
>> diff --git a/drivers/video/omap2/dss/dss.c
>> b/drivers/video/omap2/dss/dss.c
>> index 054c2a2..21a3dc8 100644
>> --- a/drivers/video/omap2/dss/dss.c
>> +++ b/drivers/video/omap2/dss/dss.c
>> @@ -473,6 +473,42 @@ int dss_calc_clock_rates(struct dss_clock_info
>> *cinfo)
>>       return 0;
>>   }
>>
>> +bool dss_div_calc(unsigned long fck_min, dss_div_calc_func func, void
>> *data)
>> +{
>> +    int fckd, fckd_start, fckd_stop;
>> +    unsigned long fck;
>> +    unsigned long fck_hw_max;
>> +    unsigned long fckd_hw_max;
>> +    unsigned long prate;
>> +
>> +    if (dss.dpll4_m4_ck == NULL) {
>> +        /* XXX can we change the clock on omap2? */
> 
> We can change dss_fclk1 on omap2, and the cclock2420_data.c and
> cclock2430_data.c have clksel structs which allow a set of dividers. The
> dividers are not continuous though, 1 to 12 and 16 are allowed. So we
> might need to change the code here a bit, if we want to change the clock
> in the first place.

Ok, good to know. Note that the comment is copied from the old code. I
think I tried changing the clock on N800 with clk_set_rate long ago, but
I didn't get it to work. Things might have changed, but, well, I don't
think we should spend time on omap2 code. I'm sure we'll get a patch if
somebody needs it =).

 Tomi



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