From: Jan Glauber <jan.glauber@caviumnetworks.com>
To: Wolfram Sang <wsa@the-dreams.de>
Cc: <linux-kernel@vger.kernel.org>, <linux-i2c@vger.kernel.org>,
David Daney <ddaney@caviumnetworks.com>
Subject: Re: [PATCH v6 07/19] i2c: octeon: Use i2c recovery framework
Date: Thu, 21 Apr 2016 15:08:35 +0200 [thread overview]
Message-ID: <20160421130835.GA2623@hardcore> (raw)
In-Reply-To: <20160420213121.GC1546@katana>
On Wed, Apr 20, 2016 at 11:31:21PM +0200, Wolfram Sang wrote:
> On Mon, Apr 11, 2016 at 05:28:38PM +0200, Jan Glauber wrote:
> > Switch to the i2c bus recovery framework using generic SCL recovery.
> > If this fails try to reset the hardware. The recovery is triggered
> > during START on timeout of the interrupt or failure to reach
> > the START / repeated-START condition.
> >
> > The START function is moved to xfer and while at it:
> > - removed xfer debug message (i2c core already provides debugging)
> > - removed length is zero check
> >
> > Signed-off-by: Jan Glauber <jglauber@cavium.com>
> > ---
> > drivers/i2c/busses/i2c-octeon.c | 178 +++++++++++++++++++++++++---------------
> > 1 file changed, 111 insertions(+), 67 deletions(-)
>
> Interesting, it got larger...
>
> >
> > +/**
> > + * octeon_i2c_write_int - read the TWSI_INT register
>
> read_int
OK
> > + int ret, retries = 2;
>
> I don't think 'retries' makes sense here. On failure, you return
> -EAGAIN, so the core will retry 'adapter->retries' times anyhow.
OK. I'll remove the retry looping and call recovery once
if the START condition is not reached. If recovery succeeds
I'll return -EAGAIN, otherwise the error code.
> > - if (length < 1)
> > - return -EINVAL;
>
> So, the adapter support 0-length messages now? Or why was it there? I
> have the feeling this is a seperate patch.
I assumed this check was bogus and there are no valid 0-length
messages...
If 0-length messages can indeed happen I'll keep this check (but why
would the i2c core not check for that in a central place and return
an error before calling xfer() ?).
> > +static void octeon_i2c_prepare_recovery(struct i2c_adapter *adap)
> > +{
> > + struct octeon_i2c *i2c = i2c_get_adapdata(adap);
> > +
> > + /*
> > + * The stop resets the state machine, does not _transmit_ STOP unless
> > + * engine was active.
> > + */
> > + octeon_i2c_stop(i2c);
> > +
> > + octeon_i2c_write_int(i2c, 0);
>
> Maybe a comment why the delay?
Later patch "Flush TWSI writes with readback" adds synchronization after
octeon_i2c_write_int(), so the delays in prepare/unprepare_recovery can
go away.
> > + udelay(5);
> > +}
next prev parent reply other threads:[~2016-04-21 13:23 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-11 15:28 [PATCH v6 00/19] i2c-octeon and i2c-thunderx drivers Jan Glauber
2016-04-11 15:28 ` [PATCH v6 01/19] i2c: octeon: Increase retry default and use fixed timeout value Jan Glauber
2016-04-13 8:39 ` Wolfram Sang
2016-04-11 15:28 ` [PATCH v6 02/19] i2c: octeon: Move set-clock and init-lowlevel upward Jan Glauber
2016-04-13 8:39 ` Wolfram Sang
2016-04-11 15:28 ` [PATCH v6 03/19] i2c: octeon: Rename [read|write]_sw to reg_[read|write] Jan Glauber
2016-04-13 8:44 ` Wolfram Sang
2016-04-14 7:58 ` Jan Glauber
2016-04-14 8:58 ` Wolfram Sang
2016-04-11 15:28 ` [PATCH v6 04/19] i2c: octeon: Introduce helper functions for register access Jan Glauber
2016-04-13 8:45 ` Wolfram Sang
2016-04-14 8:05 ` Jan Glauber
2016-04-14 8:58 ` Wolfram Sang
2016-04-11 15:28 ` [PATCH v6 05/19] i2c: octeon: Remove superfluous check in octeon_i2c_test_iflg Jan Glauber
2016-04-14 8:59 ` Wolfram Sang
2016-04-11 15:28 ` [PATCH v6 06/19] i2c: octeon: Improve error status checking Jan Glauber
2016-04-13 8:55 ` Wolfram Sang
2016-04-14 8:10 ` Jan Glauber
2016-04-14 9:01 ` Wolfram Sang
2016-04-11 15:28 ` [PATCH v6 07/19] i2c: octeon: Use i2c recovery framework Jan Glauber
2016-04-20 21:31 ` Wolfram Sang
2016-04-21 13:08 ` Jan Glauber [this message]
2016-04-21 13:54 ` Wolfram Sang
2016-04-21 17:51 ` Jan Glauber
2016-04-21 21:33 ` Wolfram Sang
2016-04-11 15:28 ` [PATCH v6 08/19] i2c: octeon: Enable High-Level Controller Jan Glauber
2016-04-20 21:43 ` Wolfram Sang
2016-04-20 21:55 ` David Daney
2016-04-21 13:40 ` Jan Glauber
2016-04-21 13:55 ` Wolfram Sang
2016-04-21 14:10 ` Jan Glauber
2016-04-11 15:28 ` [PATCH v6 09/19] dt-bindings: i2c: Add Octeon cn78xx TWSI Jan Glauber
2016-04-11 15:28 ` [PATCH v6 10/19] i2c: octeon: Add support for cn78xx chips Jan Glauber
2016-04-20 21:52 ` Wolfram Sang
2016-04-20 22:28 ` David Daney
2016-04-25 21:45 ` Wolfram Sang
2016-04-11 15:28 ` [PATCH v6 11/19] i2c: octeon: Flush TWSI writes with readback Jan Glauber
2016-04-11 15:28 ` [PATCH v6 12/19] i2c: octeon: Faster operation when IFLG signals late Jan Glauber
2016-04-11 15:28 ` [PATCH v6 13/19] i2c: octeon: Add workaround for broken irqs on CN3860 Jan Glauber
2016-04-11 15:28 ` [PATCH v6 14/19] i2c: octeon: Move read function before write Jan Glauber
2016-04-11 15:28 ` [PATCH v6 15/19] i2c: octeon: Rename driver to prepare for split Jan Glauber
2016-04-11 15:28 ` [PATCH v6 16/19] i2c: octeon: Split the driver into two parts Jan Glauber
2016-04-11 15:28 ` [PATCH v6 17/19] i2c: thunderx: Add i2c driver for ThunderX SOC Jan Glauber
2016-04-11 15:28 ` [PATCH v6 18/19] i2c: octeon,thunderx: Move register offsets to struct Jan Glauber
2016-04-11 15:28 ` [PATCH v6 19/19] i2c: thunderx: Add smbus alert support Jan Glauber
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=20160421130835.GA2623@hardcore \
--to=jan.glauber@caviumnetworks.com \
--cc=ddaney@caviumnetworks.com \
--cc=linux-i2c@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=wsa@the-dreams.de \
/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).