[PATCH 15/36] ARM: OMAP2+: gpmc: Allow drivers to query GPMC_CLK period

[Roger Quadros]

On 06/13/2014 10:26 AM, Tony Lindgren wrote:
> * Roger Quadros <rogerq at ti.com> [140611 01:59]:
>> GPMC_CLK is the external clock output pin that is used for syncronous
>> accesses.
>>
>> Device drivers need to know the fastest possible GPMC_CLK period in order
>> to calculate the most optimal device timings. Add the function
>> omap_gpmc_get_clk_period() to allow drivers to get the nearset possible
>> (equal to or greater than) GPMC_CLK period given the minimum
>> clock period supported by the attached device.
>>
>> This is especially needed by the onenand driver as it calculates
>> device timings on the fly for various onenand speed grades.
> 
> Here too this should probably still be done by the gpmc to driver
> glue layer, not by the actual driver that shoud be Linux generic.

Well, this is only needed by the omap-onenand driver to perform the timing calculations at run-time.
Other option is to model the GPMC_CLK (external) as a clock and request the rate using the clock framework.
But since this and the retime() is only used by 2 OMAP specific drivers, I'm not sure if it is worth the effort.

cheers,
-roger