RE: [PATCH v5 01/10] pinctrl: generic: Add bi-directional and output-enable

From: Chris Brandt <Chris.Brandt@renesas.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>,
	Jacopo Mondi <jacopo+renesas@jmondi.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	"Russell King - ARM Linux" <linux@armlinux.org.uk>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	"linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
	devicetree <devicetree@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v5 01/10] pinctrl: generic: Add bi-directional and output-enable
Date: Fri, 28 Apr 2017 13:18:06 +0000	[thread overview]
Message-ID: <SG2PR06MB11658EC3A3A80C57E6F539AC8A130@SG2PR06MB1165.apcprd06.prod.outlook.com> (raw)
In-Reply-To: <CAHp75Vcp_eMWrjZRX-x3=Tt3JRXcL_wWG43MymF=oyLLP4EJwg@mail.gmail.com>

On Friday, April 28, 2017, Andy Shevchenko wrote:
> > In the RZ/A1 HW manual you can kind of see that in 54.18 Port Control
> Logical Diagram (but that wasn't obvious to me at first).
> 
> Please, post a link to it or copy essential parts.

This board the RZ/A1 GENMAI board.
https://www.renesas.com/en-us/products/software-tools/boards-and-kits/evaluation-demo-solution-boards/genmai-cpu-board-rtk772100bc00000br.html

The schematic is included in the "User's manual"
https://www.renesas.com/en-us/doc/products/tool/doc/003/r20ut2596ej_r7s72100evum.pdf

The RZ/A1H Hardware manual is here:
https://www.renesas.com/en-us/document/hw-manual?hwLayerShowFlg=true&prdLayerId=186374&layerName=RZ%252FA1H&coronrService=document-prd-search&hwDocUrl=%2Fen-us%2Fdoc%2Fproducts%2Fmpumcu%2Fdoc%2Frz%2Fr01uh0403ej0300_rz_a1h.pdf&hashKey=54f335753742b5add524d4725b7242e6

Chapter 54 is the port/pin controller.

"54.18 Port Control Logical Diagram" is the diagram I was talking about. Note that is says "Note: This figure shows the logic for reference, not the circuit."

"54.3.13 Port Bidirection Control Register (PBDCn)" is the magic register needed to get some pins to work.

> I'm quite skeptical  that cheap hardware can implement something more
> costable than simplest open-source / open-drain + bias

I don't think this is an open-source / open-drain + bias issue. It's a "the internal signal paths are not getting hooked up correctly" issue.

Regardless, on this part, we needed a way to flag that some pins when put in some function modes needed 'an extra register setting'. At first we tried to sneak that info in with a simple #define in the pin/pinmux DT node properties. But, Linus didn't want it there so we had to make up a new generic property called "bi-directional".

What is your end goal here? Get "bi-directional" changed to something else?

Chris