From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: device tree binding documentation outdated
Date: Fri, 4 Oct 2013 16:58:25 +0100 [thread overview]
Message-ID: <20131004155825.GO12758@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20131004154536.GB2734@S2101-09.ap.freescale.net>
On Fri, Oct 04, 2013 at 11:45:39PM +0800, Shawn Guo wrote:
> On Thu, Oct 03, 2013 at 12:49:11AM +0100, Russell King - ARM Linux wrote:
> > RGMII mode.
> >
> > In current hardware, the phy has its own 25MHz crystal. This provides
> > the phy with its clocks, and the phy itself contains a PLL, which it
> > uses to generate 125MHz.
> >
> > The phy can be (and is) configured to generate this 125MHz clock on
> > the CLK_25M pin, which is connected to the IMX6 ENET_REF_CLK pad (V22
> > ball).
> >
> > Hence, we have in DT:
> > MX6QDL_PAD_ENET_REF_CLK__ENET_TX_CLK
> >
> > So far, so good.
> >
> >
> > On current hardware, GPIO 16 is not connected to anything except some
> > 0402 resistor pads where the resistor is not fitted. On future hardware,
> > the above crystal will be removed, and the appropriate 0402 resistor
> > placed to supply a clock provided on GPIO 16 to the phy.
> >
> > Hence, to support both hardware configurations transparently, GPIO 16
> > should be configured to generate a 25MHz clock for use by the phy.
>
> On AR8035 XTLI pin? Here is what I read from AR8035 data sheet.
>
> XTLI (Analog input signal): Crystal oscillator input. Requires a 27 pF
> capacitor to GND. Support external 25 MHz, 1.2V swing clock input
> through this pin.
>
> XTLO (Analog output signal): Crystal oscillator output; 27 pF to GND.
>
> Will AR8035 just work if we provide a digital 25Mhz clock (from GPIO_16)
> on its XTLI pin?
Well, "Support external 25 MHz, 1.2V swing clock input through this pin."
suggests the answer is yes. The characterists suggest that if the supplied
clock is within -0.3 to 0.15V for the low level, and 0.8 to 1.5V for the
high level, it should work.
next prev parent reply other threads:[~2013-10-04 15:58 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-26 19:51 device tree binding documentation outdated Russell King - ARM Linux
2013-09-26 20:29 ` Fabio Estevam
2013-09-26 20:59 ` Russell King - ARM Linux
2013-09-26 23:10 ` Matt Sealey
2013-09-26 23:29 ` Russell King - ARM Linux
2013-09-26 23:48 ` Matt Sealey
2013-09-27 13:15 ` Jason Cooper
2013-09-27 17:05 ` Russell King - ARM Linux
2013-09-27 18:31 ` Russell King - ARM Linux
2013-09-27 18:52 ` Fabio Estevam
2013-09-27 20:16 ` Matt Sealey
2013-09-27 20:43 ` Russell King - ARM Linux
2013-09-26 23:25 ` Fabio Estevam
2013-09-27 12:13 ` Russell King - ARM Linux
2013-09-27 13:26 ` Shawn Guo
2013-09-27 15:19 ` Russell King - ARM Linux
2013-09-27 15:49 ` Russell King - ARM Linux
2013-09-27 16:52 ` Matt Sealey
2013-09-27 17:49 ` Russell King - ARM Linux
2013-09-27 18:33 ` Matt Sealey
2013-09-27 19:05 ` Russell King - ARM Linux
2013-09-27 19:41 ` Matt Sealey
2013-09-27 19:48 ` Matt Sealey
2013-09-27 20:21 ` Russell King - ARM Linux
2013-09-28 8:38 ` Russell King - ARM Linux
2013-09-29 6:13 ` Shawn Guo
2013-09-29 6:23 ` Duan Fugang-B38611
2013-09-29 6:35 ` Shawn Guo
2013-09-29 6:47 ` Duan Fugang-B38611
2013-10-02 19:33 ` Russell King - ARM Linux
2013-10-02 23:49 ` Russell King - ARM Linux
2013-10-03 2:21 ` Fabio Estevam
2013-10-04 15:45 ` Shawn Guo
2013-10-04 15:58 ` Russell King - ARM Linux [this message]
2013-09-29 5:01 ` Shawn Guo
2013-09-27 20:18 ` Russell King - ARM Linux
2013-09-28 3:28 ` Fabio Estevam
2013-09-26 21:35 ` Linus Walleij
2013-09-27 2:51 ` Shawn Guo
2013-09-27 8:45 ` Russell King - ARM Linux
2013-09-27 12:28 ` Shawn Guo
2013-09-27 13:12 ` Jason Cooper
2013-09-27 13:21 ` Russell King - ARM Linux
2013-09-27 13:29 ` Linus Walleij
2013-09-27 13:31 ` Jason Cooper
2013-09-27 16:33 ` Matt Sealey
2013-09-27 20:52 ` Russell King - ARM Linux
2013-09-27 13:52 ` Arnaud Patard (Rtp)
2013-09-27 15:40 ` Matt Sealey
2013-09-27 9:49 ` Russell King - ARM Linux
2013-09-27 12:08 ` Sascha Hauer
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20131004155825.GO12758@n2100.arm.linux.org.uk \
--to=linux@arm.linux.org.uk \
--cc=linux-arm-kernel@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).