Re: [PATCH v2 04/12] i2c: designware: Convert driver to using regmap API

Serge Semin
2020-05-21T02:03:03Z

On Wed, May 20, 2020 at 03:16:07PM +0300, Jarkko Nikula wrote:
> On 5/10/20 12:50 PM, Serge Semin wrote:
> > Seeing the DW I2C driver is using flags-based accessors with two
> > conditional clauses it would be better to replace them with the regmap
> > API IO methods and to initialize the regmap object with read/write
> > callbacks specific to the controller registers map implementation. This
> > will be also handy for the drivers with non-standard registers mapping
> > (like an embedded into the Baikal-T1 System Controller DW I2C block, which
> > glue-driver is a part of this series).
> >
> > As before the driver tries to detect the mapping setup at probe stage and
> > creates a regmap object accordingly, which will be used by the rest of the
> > code to correctly access the controller registers. In two places it was
> > appropriate to convert the hand-written read-modify-write and
> > read-poll-loop design patterns to the corresponding regmap API
> > ready-to-use methods.
> >
> > Note the regmap IO methods return value is checked only at the probe
> > stage. The rest of the code won't do this because basically we have
> > MMIO-based regmap so non of the read/write methods can fail (this also
> > won't be needed for the Baikal-T1-specific I2C controller).
> >
> > Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> > Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
> > Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
> > Cc: Paul Burton <paulburton@kernel.org>
> > Cc: Ralf Baechle <ralf@linux-mips.org>
> > Cc: Wolfram Sang <wsa@the-dreams.de>
> > Cc: Rob Herring <robh+dt@kernel.org>
> > Cc: Frank Rowand <frowand.list@gmail.com>
> > Cc: devicetree@vger.kernel.org
> > Cc: linux-mips@vger.kernel.org
> > ---
> > drivers/i2c/busses/Kconfig | 1 +
> > drivers/i2c/busses/i2c-designware-common.c | 171 +++++++++++++++------
> > drivers/i2c/busses/i2c-designware-core.h | 18 +--
> > drivers/i2c/busses/i2c-designware-master.c | 125 ++++++++-------
> > drivers/i2c/busses/i2c-designware-slave.c | 77 +++++-----
> > 5 files changed, 239 insertions(+), 153 deletions(-)
> >
> Looking at patches 4/12-12/12 I think it would be good to move fixes and
> less invasive patches before this. Like
>
> i2c: designware: slave: Set DW I2C core module dependency
> i2c: designware: Use `-y` to build multi-object modules
> i2c: designware: Move Baytrail sem config to the platform if-clause
>
> That said, you may add:
>
> Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
> Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>

Ok. I'll move those three patches to be before this one in v3. Thanks.

-Sergey