From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Tali Perry <tali.perry1@gmail.com>
Cc: ofery@google.com, Brendan Higgins <brendanhiggins@google.com>,
avifishman70@gmail.com, Tomer Maimon <tmaimon77@gmail.com>,
kfting@nuvoton.com, Patrick Venture <venture@google.com>,
Nancy Yuen <yuenn@google.com>,
Benjamin Fair <benjaminfair@google.com>,
Rob Herring <robh+dt@kernel.org>,
Wolfram Sang <wsa@the-dreams.de>,
linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org,
OpenBMC Maillist <openbmc@lists.ozlabs.org>,
devicetree <devicetree@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v10 2/3] i2c: npcm7xx: Add Nuvoton NPCM I2C controller driver
Date: Wed, 13 May 2020 18:24:13 +0300 [thread overview]
Message-ID: <20200513152413.GQ185537@smile.fi.intel.com> (raw)
In-Reply-To: <CAHb3i=tERsM+gwmQN1+vjnML9o5NxRK=uBokEUsd-Ljyje4s3A@mail.gmail.com>
On Mon, May 11, 2020 at 02:28:50PM +0300, Tali Perry wrote:
> On Mon, May 11, 2020 at 12:18 PM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> > On Sun, May 10, 2020 at 01:23:29PM +0300, Tali Perry wrote:
...
> > > +#if IS_ENABLED(CONFIG_DEBUG_FS)
> >
> > Why?
>
> We wanted to add an optional feature to track i2c slave status.
> the NPCM has 16 channels handling multiple devices each. Some of the devices
> are polled periodically, and might power down.
> The user wanted to implement a health monitoring option
> to occasionally check the status of the buses (how many timeouts, recovery etc.)
> This feature is optional and depends on CONFIG_DEBUG_FS The counters are exposed
> to user through the file system.
What I meant is why do you need an #ifdef?
...
> > > +#define I2C_NUM_OF_ADDR 10
> >
> > Is it 10-bit address support or what?
> >
>
> No, the NPCM has an option to respond to multiple slave addresses
> (10 own slave addresses)
Perhaps more descriptive name then?
...
> > > + // Repeat the following sequence until SDA is released
> > > + do {
> > > + // Issue a single SCL toggle
> > > + iowrite8(NPCM_I2CCST_TGSCL, bus->reg + NPCM_I2CCST);
> > > + udelay(20);
> > > + // If SDA line is inactive (high), stop
> > > + if (npcm_i2c_get_SDA(_adap)) {
> > > + done = true;
> > > + status = 0;
> > > + }
> > > + } while (!done && iter--);
> >
> > readx_poll_timeout() ?
>
> Not exactly, readx_poll_timeout includes only a read operation, here there is a
> write in the middle. (iowrite8)
Ah, indeed. Perhaps time to add writex_poll_timeout() ?
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2020-05-13 15:24 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-10 10:23 [PATCH v10 0/3] i2c: npcm7xx: add NPCM i2c controller driver Tali Perry
2020-05-10 10:23 ` [PATCH v10 1/3] dt-bindings: i2c: npcm7xx: add NPCM I2C controller Tali Perry
2020-05-11 16:09 ` Rob Herring
2020-05-10 10:23 ` [PATCH v10 2/3] i2c: npcm7xx: Add Nuvoton NPCM I2C controller driver Tali Perry
2020-05-11 9:17 ` Andy Shevchenko
2020-05-11 11:28 ` Tali Perry
2020-05-13 15:24 ` Andy Shevchenko [this message]
2020-05-10 10:23 ` [PATCH v10 3/3] i2c: npcm7xx: Add support for slave mode for Nuvoton Tali Perry
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