Hello Roger, On Wed, Oct 07, 2015 at 10:45:50AM +0300, Roger Quadros wrote: > On 06/10/15 23:07, Uwe Kleine-König wrote: > > Most register values for the chip select setup depend on the frequency > > of the fck clock. > > So add a hint that the values setup by the bootloader might differ from > > the right setup for Linux if the bootloader uses a different frequency. > > > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> > > --- > > drivers/memory/Kconfig | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/drivers/memory/Kconfig b/drivers/memory/Kconfig > > index c6a644b22af4..1414dd53be57 100644 > > --- a/drivers/memory/Kconfig > > +++ b/drivers/memory/Kconfig > > @@ -64,6 +64,9 @@ config OMAP_GPMC_DEBUG > > Enables verbose debugging mostly to decode the bootloader provided > > timings. Enable this during development to configure devices > > connected to the GPMC bus. > > + Note that you cannot just tweak your device tree until the registers > > + setup by linux match what the bootloader did because that one might > > + use a different fck frequency influencing most register settings. > > Looks like we can't know for sure the GPMC fclk used at the bootloader > else we could have just printed the GPMC fclk pre and post gpmc settings. > > How about this instead? > > NOTE: Apart from matching the register setup with the bootloader you also need to > match the GPMC FCLK frequency used by the bootloader else the GPMC timings > won't be identical with the bootloader timings. Yeah, sounds better, thanks. > Also you might need to build this patch on top of > http://article.gmane.org/gmane.linux.kernel/2054796 I talked to Tony about this patch yesterday on irc, but I didn't find it in the archives yet when I sent my mail. Thanks Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
