Re: [PATCH v4 02/11] dt-bindings: i2c: Discard i2c-slave flag from the DW I2C example

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Serge Semin <fancer.lancer@gmail.com>,
	Rob Herring <robh@kernel.org>,
	Jarkko Nikula <jarkko.nikula@linux.intel.com>,
	Wolfram Sang <wsa@the-dreams.de>,
	Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	linux-mips@vger.kernel.org, linux-i2c@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 02/11] dt-bindings: i2c: Discard i2c-slave flag from the DW I2C example
Date: Thu, 28 May 2020 13:00:00 +0300	[thread overview]
Message-ID: <20200528100000.GF1634618@smile.fi.intel.com> (raw)
In-Reply-To: <20200528083923.yjlm5ur7cslgxdau@mobilestation>

On Thu, May 28, 2020 at 11:39:23AM +0300, Serge Semin wrote:
> On Wed, May 27, 2020 at 08:56:24PM +0300, Andy Shevchenko wrote:
> > On Wed, May 27, 2020 at 08:18:41PM +0300, Serge Semin wrote:
> > > On Wed, May 27, 2020 at 11:12:04AM -0600, Rob Herring wrote:
> > > > On Wed, May 27, 2020 at 03:01:02PM +0300, Serge Semin wrote:
> > > > > dtc currently doesn't support I2C_OWN_SLAVE_ADDRESS flag set in the
> > > > > i2c "reg" property. If it is the compiler will print a warning:
> > > > > 
> > > > > Warning (i2c_bus_reg): /example-2/i2c@1120000/eeprom@64: I2C bus unit address format error, expected "40000064"
> > > > > Warning (i2c_bus_reg): /example-2/i2c@1120000/eeprom@64:reg: I2C address must be less than 10-bits, got "0x40000064"
> > > > > 
> > > > > In order to silence dtc up let's discard the flag from the DW I2C DT
> > > > > binding example for now. Just revert this commit when dtc is fixed.
> > 
> > > > >        eeprom@64 {
> > > > >          compatible = "linux,slave-24c02";
> > > > > -        reg = <0x40000064>;
> > > > > +        reg = <0x64>;
> > > > 
> > > > But the compatible is a slave, so you need an example with a different 
> > > > device.
> > > 
> > 
> > > Ok. I'll replace the sub-node with just "atmel,24c02" compatible string then.
> > 
> > But how it will be different to the another slave connected to the master?
> > 
> > This example is specifically to show that DesingWare I²C controller may be
> > switched to slave mode.
> 
> Well, dtc doesn't support it and prints warning that the address is invalid.
> Though I do understand you concern and is mostly agree with it. Let's do this in
> the next way. I'll resend the series with eeprom@64 sub-node replaced with just
> a normal eeprom-device. The message log will have an info why this has been
> done. In the non-mergeable section of the patch I'll suggest to Rob reconsider
> the patch acking, since we can leave the slave-marked sub-node and just live
> with the dtc warning until it's fixed in there.

Thanks!

-- 
With Best Regards,
Andy Shevchenko