linux-kernel - Re: [PATCH V5 4/8] mfd: da9061: MFD core support

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Date:   Wed, 4 Jan 2017 12:18:30 +0000
From:   Lee Jones <lee.jones@...aro.org>
To:     Steve Twiss <stwiss.opensource@...semi.com>
Cc:     LINUX-KERNEL <linux-kernel@...r.kernel.org>,
        DEVICETREE <devicetree@...r.kernel.org>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Eduardo Valentin <edubezval@...il.com>,
        Guenter Roeck <linux@...ck-us.net>,
        LINUX-INPUT <linux-input@...r.kernel.org>,
        LINUX-PM <linux-pm@...r.kernel.org>,
        LINUX-WATCHDOG <linux-watchdog@...r.kernel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Rob Herring <robh+dt@...nel.org>,
        Support Opensource <Support.Opensource@...semi.com>,
        Wim Van Sebroeck <wim@...ana.be>,
        Zhang Rui <rui.zhang@...el.com>
Subject: Re: [PATCH V5 4/8] mfd: da9061: MFD core support

On Wed, 04 Jan 2017, Steve Twiss wrote:

> Hi Lee,
> 
> On 04 January 2017 10:12, Lee Jones wrote:
> 
> > Subject: Re: [PATCH V5 4/8] mfd: da9061: MFD core support
> > On Thu, 15 Dec 2016, Steve Twiss wrote:
> > > From: Steve Twiss <stwiss.opensource@...semi.com>
> 
> [...]
> 
> > > +static const struct of_device_id da9062_dt_ids[] = {
> > > +	{ .compatible = "dlg,da9061", .data = (void *)COMPAT_TYPE_DA9061,
> > },
> > > +	{ .compatible = "dlg,da9062", .data = (void *)COMPAT_TYPE_DA9062,
> > },
> > 
> > It looks like this device can dynamically obtain this information from
> > the device.  Please use that method instead.
> 
> As I mentioned in an earlier post,
> https://lkml.org/lkml/2016/11/7/418
> 
> The 61/62 device type has been defined by the device tree in this case, and
> that definition is used to set the register map. With the regmap defined,
> access to the registers is then possible.
> 
> It is not possible to detect the device type automatically in this case because
> it suggests a predefined regmap.
> 
> This is the reason I define the chip type (DA9061 or DA9062) in the device
> tree and then assign the correct regmap first before accessing any registers.

Well at least I'm consistent. :D

> > > +	if (i2c->dev.of_node) {
> > > +		match = of_match_node(da9062_dt_ids, i2c->dev.of_node);
> > > +		if (!match)
> > > +			return -EINVAL;
> > > +
> > > +		chip->chip_type = (int)match->data;
> > > +	} else
> > > +		chip->chip_type = id->driver_data;
> > 
> > Please obtain this information from DA9062AA_VARIANT_ID.
> 
> The variant ID does contain the information about whether it is a 61 or 62, but
> in order to read the register the regmap definition needs to be defined
> first.
> 
> [...]
> 
> > >  static const struct i2c_device_id da9062_i2c_id[] = {
> > > -	{ "da9062", 0 },
> > > +	{ "da9061", COMPAT_TYPE_DA9061 },
> > > +	{ "da9062", COMPAT_TYPE_DA9062 },
> > 
> > This too.
> 
> Regards,
> Steve

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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