From mboxrd@z Thu Jan  1 00:00:00 1970
From: Timur Tabi <timur@codeaurora.org>
Subject: Re: Sparse GPIO maps with pinctrl-msm.c?
Date: Fri, 16 Jun 2017 11:26:49 -0500
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To: Andy Gross <andy.gross@linaro.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>, Stephen Boyd <sboyd@codeaurora.org>, linux-gpio@vger.kernel.org

On 6/16/17 11:21 AM, Andy Gross wrote:

>> 1) Approved by the XPU
> 
> How do you know what this is?  And this changes based on the TZ load.

An ACPI property in the TLMM node that lists the approved GPIOs by 
number.  It currently looks like this:

Name (_DSD, Package ()
{
	ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
	Package ()
	{
		// Expose only the qdss_tracedata pins as GPIOs,
		// numbered sequentially, so that "gpio X" maps
		// to qdss_tracedata[X].  These can be used as
		// generic GPIOs.
		Package (2) {"gpios", Package ()
			{116, 117, 118, 119, 120, 121, 122, 123,
			 124, 125, 126, 127, 128, 129, 130, 131,
			 80, 81, 82, 83, 84, 85, 86, 87, 88, 89,
			 90, 50, 36, 37, 38, 39}}
	}
})

I'm not crazy about it, but it's a compromise that allows some GPIOs to 
be exposed without a lot of coding.  One idea we're debating is 
forgetting about pinctrl-msm altogether and rewrite the driver from 
scratch as a pure GPIO driver.  I'm hoping to avoid having to do that.

-- 
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the
Code Aurora Forum, hosted by The Linux Foundation.