On Tue, Jul 17, 2018 at 01:34:36PM +0000, Alexey Brodkin wrote: > Hi Alexander, Tom, > > > -----Original Message----- > > From: Alexander Graf [mailto:[email protected]] > > Sent: Tuesday, July 17, 2018 4:33 PM > > To: Tom Rini <[email protected]> > > Cc: Wolfgang Denk <[email protected]>; Felix Brack <[email protected]>; > > [email protected]; Stefan Roese <[email protected]>; Alexey Brodkin > > <[email protected]>; Michal Simek <[email protected]> > > Subject: Re: [U-Boot] [PATCH] serial: ns16550: Add register shift variable > > > > On 07/17/2018 03:25 PM, Tom Rini wrote: > > > On Mon, Jul 16, 2018 at 02:53:26PM +0200, Alexander Graf wrote: > > >> On 07/14/2018 05:49 PM, Tom Rini wrote: > > >>> On Sat, Jul 14, 2018 at 12:47:21PM +0200, Wolfgang Denk wrote: > > >>>> Dear Felix, > > >>>> > > >>>> In message <[email protected]> you wrote: > > >>>>> The motivation for writing this patch originates in the > > >>>>> effort of synchronizing U-Boot DT to Linux DT for am33xx SOCs. > > >>>>> The current am33xx.dtsi file from U-Boot defines the <reg-shift> > > >>>>> property for all UART nodes. The actual (4.18+) am33xx.dtsi > > >>>>> file from Linux does not define <reg-shift> anymore. To prevent > > >>>>> (probably difficult) changes in many .dts and .dtsi files once > > >>>>> the synchronization is done, one can use this new variable. For > > >>>>> the pdu001 board, for example, SYS_NS16550_REG_SHIFT is set > > >>>>> to 2; no need to clutter U-Boot and board specific dts files > > >>>>> with <reg-shift> properties. > > >>>> Does this mean that U-Boot will not be able to use the same DTB as > > >>>> Linux? > > >>> To be clear, it's the other way around. We can't use the Linux dtb/dts > > >>> files as they've dropped (and in other cases, aren't adding) these > > >>> properties as it's handled differently. > > >> What does "differently" mean? Linux tries quite hard to be platform > > >> agnostic, so a per-build-target #define surely isn't what they're doing. > > > Yes, what exactly is the Linux kernel doing here? > > > > > > Linux has a completely separate driver for omap3 (which is wrong too). > > But in a nutshell, it basically determines the shift value by the > > "compatible" string, so we should too. > > Here's the driver: > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/tty/serial/omap-serial.c
But I would swear that's also not required and the generic ns1655x driver can be used. -- Tom
signature.asc
Description: PGP signature
_______________________________________________ U-Boot mailing list [email protected] https://lists.denx.de/listinfo/u-boot
