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

[Tom Warren]

Allen,

> -----Original Message-----
> From: Allen Martin [mailto:amartin at nvidia.com]
> Sent: Monday, May 13, 2013 7:12 PM
> To: Tom Warren
> Cc: Simon Glass; Stephen Warren; U-Boot Mailing List
> Subject: Re: [PATCH] Tegra: clk: always use find_best_divider() for periph
> clocks
> 
> 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

Nice. Thanks. I'll add it to u-boot-tegra/next tomorrow or Weds.

Tom
> 
> -Allen
--
nvpublic