Re: [SPAM] [PATCH v3 1/1] mfd: Add I2C based System Configuaration (SYSCON) access

From: Lee Jones <lee.jones@linaro.org>
To: Michael Walle <michael@walle.cc>
Cc: devicetree@vger.kernel.org, arnd@arndb.de,
	gregkh@linuxfoundation.org, linus.walleij@linaro.org,
	linux-kernel@vger.kernel.org, robh+dt@kernel.org,
	bgolaszewski@baylibre.com, broonie@kernel.org,
	andriy.shevchenko@linux.intel.com,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [SPAM] [PATCH v3 1/1] mfd: Add I2C based System Configuaration (SYSCON) access
Date: Thu, 18 Jun 2020 11:11:03 +0100	[thread overview]
Message-ID: <20200618101103.GD954398@dell> (raw)
In-Reply-To: <46f098524c7bf13dd6adbd1faeb8c758@walle.cc>

Ha ha!  SPAM!

On Thu, 18 Jun 2020, Michael Walle wrote:
> Am 2020-06-18 10:02, schrieb Lee Jones:
> > The existing SYSCON implementation only supports MMIO (memory mapped)
> > accesses, facilitated by Regmap.  This extends support for registers
> > held behind I2C busses.
> > 
> > Signed-off-by: Lee Jones <lee.jones@linaro.org>
> > ---
> > Changelog:
> > 
> > v2 => v3
> >   - Change 'is CONFIG' present check to include loadable modules
> >     - s/#ifdef CONFIG_MFD_SYSCON_I2C/#if
> > IS_ENABLED(CONFIG_MFD_SYSCON_I2C)/
> > 
> > v1 => v2
> >   - Remove legacy references to OF
> >   - Allow building as a module (fixes h8300 0-day issue)
> > 
> > drivers/mfd/Kconfig            |  7 +++
> >  drivers/mfd/Makefile           |  1 +
> >  drivers/mfd/syscon-i2c.c       | 90 ++++++++++++++++++++++++++++++++++
> >  include/linux/mfd/syscon-i2c.h | 26 ++++++++++
> >  4 files changed, 124 insertions(+)
> >  create mode 100644 drivers/mfd/syscon-i2c.c
> >  create mode 100644 include/linux/mfd/syscon-i2c.h

[...]

> > +static const struct regmap_config syscon_i2c_regmap_config = {
> > +	.reg_bits = 8,
> > +	.val_bits = 8,
> > +};
> 
> What about other configs? eg. 16 bit offsets. And putting that
> config into the device tree, was always pushed back so far.

We can pass it as a parameter, no problem there.  Although it does
sounds H/W related, so not sure why it wouldn't be allowed in DT.

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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