linux-kernel - Re: [PATCH] mfd: qcom-spmi-pmic: Add support for more chips versions

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Date:	Wed, 12 Nov 2014 11:12:23 +0200
From:	"Ivan T. Ivanov" <iivanov@...sol.com>
To:	Courtney Cavin <courtney.cavin@...ymobile.com>
Cc:	Bjorn Andersson <bjorn@...o.se>, Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Samuel Ortiz <sameo@...ux.intel.com>,
	Lee Jones <lee.jones@...aro.org>,
	Stanimir Varbanov <svarbanov@...sol.com>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	linux-arm-msm <linux-arm-msm@...r.kernel.org>
Subject: Re: [PATCH] mfd: qcom-spmi-pmic: Add support for more chips versions


On Tue, 2014-11-11 at 12:27 -0800, Courtney Cavin wrote:
> On Fri, Nov 07, 2014 at 04:40:52PM +0100, Ivan T. Ivanov wrote:
> > 
> > Forgot to add. PMIC subtype and version are used also in charger and BMS
> > drivers to workaround hardware issues.
> 
> All of the blocks on the PM8x41 series have their own version numbers.
> There's no need to look at the chip revision.

I am suspecting that, for whatever the reason is, after updates inside blocks,
the PMIC chip revisions update was made instead of blocks own version update.

> 
> In fact, the SMBB (charger) documentation (80-NA555-12) specifically

It would be nice if I had this document :-).

> refers to the SMBB_MISC block revision registers as the method for
> determining the hardware version.  The "qpnp-charger" SMBB driver in the
> CAF 3.4 & 3.10 trees utilizes block specific revision numbers, as do the
> "qpnp-bms" BMS driver, the "qpnp-adc-current" IADC driver, and the
> "qpnp-adc-voltage" VADC driver.

Hm, they read its own block revision, but they are using PMIC chip revision
for workaround decisions. What could be the reason for this?

> 
> The revision of the PMIC itself should be completely irrelevant to any
> of the software interfacing with it.
> 

It will be really nice if this is the case, but I am afraid it is not.

Regards,
Ivan



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