[U-Boot] [PATCH] Tegra: clk: always use find_best_divider() for periph clocks

[Allen Martin <amartin@nvidia.com>]

On Mon, May 13, 2013 at 10:24:17AM -0700, Tom Warren wrote:
> Allen,
> 
> > -----Original Message-----
> > From: sjg at google.com [mailto:sjg at google.com] On Behalf Of Simon Glass
> > Sent: Friday, May 10, 2013 8:06 PM
> > To: Allen Martin
> > Cc: Tom Warren; Stephen Warren; U-Boot Mailing List
> > Subject: Re: [PATCH] Tegra: clk: always use find_best_divider() for periph
> > clocks
> > 
> > On Fri, May 10, 2013 at 8:56 PM, Allen Martin <amartin@nvidia.com> wrote:
> > > When adjusting peripheral clocks always use find_best_divider()
> > > instead of clk_get_divider() even when a secondary divider is not
> > > available.  In the case where is requested clock is too slow to be
> > > derived from the parent clock this allows a best effort to get close
> > > to the requested clock.
> > >
> > > This comes up for commands like "sf" where the user can pass a clock
> > > speed on the command line or "sspi" where the clock is hardcoded to
> > > 1MHz, but the Tegra114 SPI controller can't go that low.
> 
> Did you test all other periphs and check their config'd clocks to make sure this doesn't affect anything else negatively? This proc is pretty universal (called by clock_start_periph_pll, which is used by MMC/I2C/USB/display drivers).
> 

Testing done:

tegra20 seaboard:
 usb read/write
 i2c read
 emmc read
 sdcard read/write
 lcd
 uart read/write

tegra20 trimslice:
 spi read
 uart read/write

tegra30 cardhu:
 spi read/write
 uart read/write
 i2c read
 sdcard read/write
 emmc read

tegra114 dalmore:
 iwc read
 sdcard read/write
 emmc read
 uart read/write

-Allen
-- 
nvpublic