[U-Boot] [PATCH] Tegra: clk: always use find_best_divider() for periph clocks
Allen Martin
amartin at nvidia.com
Tue May 14 04:11:41 CEST 2013
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 at 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
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