LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: "Lennart Sorensen" <lsorense@csclub.uwaterloo.ca>
To: Nishanth Menon <nm@ti.com>
Cc: Tony Lindgren <tony@atomide.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	"linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	Linux-OMAP <linux-omap@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	Lokesh Vutla <lokeshvutla@ti.com>
Subject: Re: [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration
Date: Wed, 15 Apr 2015 14:44:54 -0400	[thread overview]
Message-ID: <20150415184454.GT29558@csclub.uwaterloo.ca> (raw)
In-Reply-To: <552E9714.10001@ti.com>

On Wed, Apr 15, 2015 at 11:51:32AM -0500, Nishanth Menon wrote:
> I am yet to post a new revision to this series - few other stuff got
> in the way. IODelay driver in no way removes the constraint that the
> SoC architecture has - most of the pins still need to be muxed in
> bootloader - we cannot escape that. The reasoning for doing the mux in
> bootloader is independent of the need for iodelay.
> 
> Reasoning for mux in bootloader is because the mux and pull fields are
> glitchy - much more than previous generations of TI SoCs and
> significantly long enough to cause issues depending on the pins being
> muxed.

Well if we know glitching is NOT an issue on our boards, then we don't
have to do anything in the boot loader other than the basic setup for
the serial console and emmc and SD, which has always been necesary.

I consider moving the mux setup to the bootloader a terrible design and
won't go along with it.  We make sure all external devices have reset
lines being held while the pinmux is being setup, so glitching is a
non issue.

> Reasoning for iodelay is different - it is a hardware block meant to
> control the timing of signals in a particular signal path to ensure
> that specification compliance is met.
> 
> Lets try not to mix the two.

Well I was told by multiple people from TI that the reason for moving
the pinmux setup to the bootloader was because of the iodelay issue,
so you will have to get the message made clear within TI then.

-- 
Len Sorensen

  reply	other threads:[~2015-04-15 18:44 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-04  0:00 [PATCH 0/2] pinctrl: Introduce support for iodelay module in TI SoCs Nishanth Menon
2015-03-04  0:00 ` [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration Nishanth Menon
2015-03-10 10:39   ` Linus Walleij
2015-03-10 15:06     ` Nishanth Menon
2015-03-10 15:33     ` Tony Lindgren
2015-03-10 17:25       ` Nishanth Menon
2015-03-10 17:31         ` Tony Lindgren
2015-03-10 18:33           ` Nishanth Menon
2015-03-10 19:20             ` Nishanth Menon
2015-03-18  1:30             ` Linus Walleij
2015-03-18  1:41               ` Tony Lindgren
2015-04-15  1:29                 ` Lennart Sorensen
2015-04-15 16:51                   ` Nishanth Menon
2015-04-15 18:44                     ` Lennart Sorensen [this message]
2015-04-15 18:53                       ` Nishanth Menon
2015-03-04  0:00 ` [PATCH 2/2] pinctrl: Introduce TI IOdelay configuration driver Nishanth Menon
2015-03-04 22:58   ` Paul Bolle
2015-03-04 22:58     ` Tony Lindgren
2015-03-05  2:22       ` Nishanth Menon
2015-03-10 11:03   ` Linus Walleij
2015-03-11 12:39     ` Nishanth Menon

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=20150415184454.GT29558@csclub.uwaterloo.ca \
    --to=lsorense@csclub.uwaterloo.ca \
    --cc=devicetree@vger.kernel.org \
    --cc=linus.walleij@linaro.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-gpio@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-omap@vger.kernel.org \
    --cc=lokeshvutla@ti.com \
    --cc=nm@ti.com \
    --cc=tony@atomide.com \
    --subject='Re: [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI'\''s IODelay configuration' \
    /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

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).