From: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
To: Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Cc: Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
"devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
U-Boot Mailing List
<u-boot-0aAXYlwwYIKGBzrmiIFOJg@public.gmane.org>,
Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>,
Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>,
Joe Hershberger <joe.hershberger-acOepvfBmUk@public.gmane.org>,
Masahiro Yamada
<yamada.masahiro-uWyLwvC0a2jby3iVrkZq2A@public.gmane.org>,
Masahiro Yamada
<yamada.m-NAum8xwdG0+S7A1Ibl2khg@public.gmane.org>,
Marek Vasut <marek.vasut-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Tom Rini <trini-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>,
Albert Aribaud
<albert.u.boot-LhW3hqR2+23R7s880joybQ@public.gmane.org>,
Vikas Manocha <vikas.manocha-qxv4g6HH51o@public.gmane.org>,
Pavel Herrmann
<morpheus.ibis-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: [PATCH 11/20] dm: serial: Update binding for PL01x serial UART
Date: Wed, 15 Jul 2015 11:38:33 +0200 [thread overview]
Message-ID: <1510062.S45KkZCs96@wuerfel> (raw)
In-Reply-To: <CACRpkdb=t21=qpqar5VXd4mtqTWrq6MvoX1OsVgmWpkyFqhj3w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
On Wednesday 15 July 2015 11:00:59 Linus Walleij wrote:
> On Wed, Jul 8, 2015 at 4:53 AM, Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> wrote:
>
> > This binding differs from that of Linux. Update it and change existing
> > users.
> >
> > Signed-off-by: Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
>
> I'm confused by this. Isn't devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org the place to discuss
> device tree bindings? This is sent only to the U-Boot list, does this mean
> that there will now be *two* ontologies for DT bindings? That sounds like
> a recepie for ... something not good.
>
> > +- clock-frequency:
> > + Input clock frequency for UART.
>
> This is the real trick is it not?
>
> Is the real commit blurb for this patch something like:
>
> "we want a simple way to look up the clock frequency for our serial
> ports during early boot, and following clocks = <&...> phandles
> is too much trouble and might imply having to implement a whole
> clock framework in U-Boot so we just see a lot of trouble, instead
> provide a default frequency here"
>
> I suggest in that case, instead do this:
>
> - boot-frequency:
> input clock frequency at boot time, to be used by boot loaders
> and other early access.
>
> This would be good for early Linux stuff as well I believe and I
> do not think it's very controversial.
The CHRP ISA binding defines that a 8250 compatible UART must have this
property:
"clock-frequency" S
Standard property, encoded as with encode-int, that shall be the baud-rate
generator's clock input frequency (in hertz).
Typically, the clock frequency is nominally 1,843,200 Hz. Some devices
generate the baud rate input clock by dividing a higher-frequency clock
source that is not an exact multiple of 1,843,200 Hz, resulting in a
small but acceptable error in the nominal clock frequency. In such cases,
the "clock-frequency" shall report the actual nominal frequency. For
example, if the baud rate input clock is generated by dividing a 24
MHz clock by 13, the value of the "clock-frequency" property shall be 1846153.
Arnd
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WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 11/20] dm: serial: Update binding for PL01x serial UART
Date: Wed, 15 Jul 2015 11:38:33 +0200 [thread overview]
Message-ID: <1510062.S45KkZCs96@wuerfel> (raw)
In-Reply-To: <CACRpkdb=t21=qpqar5VXd4mtqTWrq6MvoX1OsVgmWpkyFqhj3w@mail.gmail.com>
On Wednesday 15 July 2015 11:00:59 Linus Walleij wrote:
> On Wed, Jul 8, 2015 at 4:53 AM, Simon Glass <sjg@chromium.org> wrote:
>
> > This binding differs from that of Linux. Update it and change existing
> > users.
> >
> > Signed-off-by: Simon Glass <sjg@chromium.org>
>
> I'm confused by this. Isn't devicetree at vger.kernel.org the place to discuss
> device tree bindings? This is sent only to the U-Boot list, does this mean
> that there will now be *two* ontologies for DT bindings? That sounds like
> a recepie for ... something not good.
>
> > +- clock-frequency:
> > + Input clock frequency for UART.
>
> This is the real trick is it not?
>
> Is the real commit blurb for this patch something like:
>
> "we want a simple way to look up the clock frequency for our serial
> ports during early boot, and following clocks = <&...> phandles
> is too much trouble and might imply having to implement a whole
> clock framework in U-Boot so we just see a lot of trouble, instead
> provide a default frequency here"
>
> I suggest in that case, instead do this:
>
> - boot-frequency:
> input clock frequency at boot time, to be used by boot loaders
> and other early access.
>
> This would be good for early Linux stuff as well I believe and I
> do not think it's very controversial.
The CHRP ISA binding defines that a 8250 compatible UART must have this
property:
"clock-frequency" S
Standard property, encoded as with encode-int, that shall be the baud-rate
generator's clock input frequency (in hertz).
Typically, the clock frequency is nominally 1,843,200 Hz. Some devices
generate the baud rate input clock by dividing a higher-frequency clock
source that is not an exact multiple of 1,843,200 Hz, resulting in a
small but acceptable error in the nominal clock frequency. In such cases,
the "clock-frequency" shall report the actual nominal frequency. For
example, if the baud rate input clock is generated by dividing a 24
MHz clock by 13, the value of the "clock-frequency" property shall be 1846153.
Arnd
next prev parent reply other threads:[~2015-07-15 9:38 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-08 2:53 [U-Boot] [PATCH 00/20] arm: rpi: Enable USB and Ethernet driver model Raspberry Pi Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 01/20] dm: net: Support usbethaddr environment variable Simon Glass
2015-07-08 4:04 ` Joe Hershberger
2015-07-08 20:31 ` Simon Glass
2015-07-08 20:43 ` Joe Hershberger
2015-07-08 21:07 ` Simon Glass
2015-07-20 13:56 ` Simon Glass
2015-07-20 18:10 ` Joe Hershberger
2015-07-21 21:25 ` Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 02/20] dm: usb: Allow USB Ethernet whenever CONFIG_DM_ETH is not defined Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 03/20] dm: usb: Add an errno.h header to usb_ether.c Simon Glass
2015-07-27 23:31 ` Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 04/20] dm: usb: Prepare dwc2 driver for driver-model conversion Simon Glass
2015-07-27 23:31 ` Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 05/20] dm: usb: Add driver-model support to dwc2 Simon Glass
2015-07-27 23:32 ` Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 06/20] net: smsc95xx: Sort the include files Simon Glass
2015-07-27 23:32 ` Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 07/20] net: smsc95xx: Rename AX_RX_URB_SIZE to RX_URB_SIZE Simon Glass
2015-07-27 23:32 ` Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 08/20] net: smsc95xx: Correct the error numbers Simon Glass
2015-07-27 23:32 ` Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 09/20] net: smsc95xx: Prepare for conversion to driver model Simon Glass
2015-07-27 23:32 ` Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 10/20] net: smsc95xx: Add driver-model support Simon Glass
2015-07-27 23:32 ` Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 11/20] dm: serial: Update binding for PL01x serial UART Simon Glass
2015-07-08 22:00 ` Vikas MANOCHA
[not found] ` <1436324032-17931-12-git-send-email-sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
2015-07-15 9:00 ` Linus Walleij
2015-07-15 9:00 ` [U-Boot] " Linus Walleij
[not found] ` <CACRpkdb=t21=qpqar5VXd4mtqTWrq6MvoX1OsVgmWpkyFqhj3w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-07-15 9:38 ` Arnd Bergmann [this message]
2015-07-15 9:38 ` Arnd Bergmann
2015-07-15 10:08 ` Linus Walleij
2015-07-15 10:08 ` [U-Boot] " Linus Walleij
[not found] ` <CACRpkdakAVcBT8phhbFjE+mkfA0pTcHYiaL0dV4UNieH54fd+w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-07-15 10:17 ` Arnd Bergmann
2015-07-15 10:17 ` [U-Boot] " Arnd Bergmann
2015-07-16 7:41 ` Geert Uytterhoeven
2015-07-16 7:41 ` [U-Boot] " Geert Uytterhoeven
2015-10-19 7:19 ` Linus Walleij
2015-10-19 7:19 ` [U-Boot] " Linus Walleij
2015-07-08 2:53 ` [U-Boot] [PATCH 12/20] dm: Support address translation for simple-bus Simon Glass
2015-07-27 23:32 ` Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 13/20] arm: rpi: Define CONFIG_TFTP_TSIZE to show tftp size info Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 14/20] arm: rpi: Bring in kernel device tree files Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 15/20] arm: rpi: Device tree modifications for U-Boot Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 16/20] arm: rpi: Enable device tree control for Rasberry Pi Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 17/20] arm: rpi: Drop the UART console platform data Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 18/20] arm: rpi: Drop the GPIO " Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 19/20] arm: rpi: Move to driver model for USB Simon Glass
2015-07-08 2:53 ` [U-Boot] [PATCH 20/20] arm: rpi: Use driver model for Ethernet Simon Glass
2015-07-11 5:34 ` [U-Boot] [PATCH 00/20] arm: rpi: Enable USB and Ethernet driver model Raspberry Pi Stephen Warren
2015-07-11 14:04 ` Simon Glass
2015-07-14 4:52 ` Stephen Warren
2015-07-14 15:44 ` Simon Glass
2015-07-24 4:17 ` Stephen Warren
2015-07-24 13:44 ` Tom Rini
2015-07-28 3:10 ` Stephen Warren
2015-07-28 13:55 ` Tom Rini
2015-07-28 15:44 ` Simon Glass
2015-08-01 3:10 ` Stephen Warren
2015-08-01 3:01 ` Stephen Warren
2015-07-16 14:10 ` Pavel Machek
2015-07-20 14:25 ` Simon Glass
2015-07-24 4:20 ` Stephen Warren
2015-08-03 23:45 ` Marek Vasut
2015-08-04 0:07 ` Simon Glass
2015-08-04 0:37 ` Marek Vasut
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