From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753586AbdBARSI (ORCPT ); Wed, 1 Feb 2017 12:18:08 -0500 Received: from mail-wm0-f65.google.com ([74.125.82.65]:34666 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753080AbdBARSD (ORCPT ); Wed, 1 Feb 2017 12:18:03 -0500 MIME-Version: 1.0 In-Reply-To: <20170118215755.xoamoc2rrzhy4kyz@rob-hp-laptop> References: <1484260543-80300-1-git-send-email-christopher.lee.bostic@gmail.com> <20170118215755.xoamoc2rrzhy4kyz@rob-hp-laptop> From: Christopher Bostic Date: Wed, 1 Feb 2017 11:17:51 -0600 Message-ID: Subject: Re: [PATCH v2 15/18] drivers/fsi: Add documentation for GPIO based FSI master To: Rob Herring Cc: Mark Rutland , linux@armlinux.org.uk, Greg KH , Michael Turquette , geert+renesas@glider.be, Open List OF Flattened dev tree bindings , "Moderated list: ARM PORT" , Joel Stanley , Jeremy Kerr , Linux open list , Andrew Jeffery , Alistair Popple , Benjamin Herrenschmidt , Chris Bostic Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 18, 2017 at 3:57 PM, Rob Herring wrote: > On Thu, Jan 12, 2017 at 04:35:43PM -0600, christopher.lee.bostic@gmail.com wrote: >> From: Chris Bostic >> >> Define the device tree bindings for the GPIO master type. >> >> Signed-off-by: Chris Bostic >> >> --- >> >> V2 - Break out this documentation update from the code implementing >> The GPIO master function. >> >> - Move the documentation to an earlier patch than the code >> implementing the function. >> >> - Document all 'compatible' strings used in the series. >> >> - Write binding document in terms of hardware, not software. >> >> - Elaborate on what a GPIO based FSI master is versus a non >> GPIO based master. >> >> - Give a more detailed description of what each pin in the GPIO >> FSI master is to be used for. >> >> - Re-order compatible strings in example so that most specific >> comes first. >> >> - Indicate the proper order each pin should be initialized. >> >> - Fix an unmatched '>' bracket in the example for binding. >> >> - Bracket each element of the example list items individually. >> --- >> .../devicetree/bindings/fsi/fsi-master-gpio.txt | 71 ++++++++++++++++++++++ >> 1 file changed, 71 insertions(+) >> create mode 100644 Documentation/devicetree/bindings/fsi/fsi-master-gpio.txt >> >> diff --git a/Documentation/devicetree/bindings/fsi/fsi-master-gpio.txt b/Documentation/devicetree/bindings/fsi/fsi-master-gpio.txt >> new file mode 100644 >> index 0000000..5d589bf >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/fsi/fsi-master-gpio.txt >> @@ -0,0 +1,71 @@ >> +Device-tree bindings for FSI master implemented with GPIO >> +--------------------------------------------------------- >> + >> +Typically a FSI master is defined in hardware with output control >> +lines designated for Enable, Data, Clock, etc.. In the case of >> +a 'GPIO FSI master', however, it may be the case that there is no >> +such master defined in hardware and must be implemented in standard >> +GPIO to interact with its slaves. In this 'virtual' FSI master >> +case the GPIO pins representing clk and data are directly >> +connected to the slaves. >> + >> +The GPIO FSI master node >> +------------------------- >> +This node describes a FSI master implmented with GPIO. >> +Required property: >> + compatible = "ibm,fsi-master-gpio" > > Generally, we don't have a vendor prefix for GPIO based implementations. > Hi Rob Will make the change in the next revision (v4). >> + >> +The standard FSI master node >> +---------------------------- >> +This node describes a FSI master implmemented fully in hardware >> +with dedicated input/output pins required for its function (i.e. >> +not using generic GPIO pins). >> +Required property: >> + compatible = "ibm,fsi-master" > > This and GPIO binding should be in 2 docs. > Will separate out. >> + >> + >> +GPIO FSI master property/pin descriptions >> +------------------------------------------ >> +clk - The master controlled clock line that indicates to the >> + slave when to read in or send out new data - required. >> +data - The serial data line containing information to be sent or >> + received by the master. This line is bi-directional. During >> + command phase the master controls the line and when a response >> + is required the slave takes control - required. >> +enable - Controls power state of data line - optional. >> +trans - Voltage translator control. In some applications the data line >> + must have its signal levels altered by a translator. If this is >> + necessary then control of signal direction is managed via this >> + line - optional. >> +mux - Multiplexor control. This activates/deactivates the data line >> + in cases where it is one of many possible selections via mux - >> + optional. > > Combine these descriptions and the property names, grouped as below. > Will update. >> + >> +Required properties: >> + - compatible = "ibm,fsi-master-gpio"; >> + - clk-gpios; >> + - data-gpios; >> + >> +Optional properties: >> + - enable-gpios; >> + - trans-gpios; >> + - mux-gpios; >> + >> +Order of property activation: >> +1. clk >> +2. data >> +3. trans >> +4. enable >> +5. mux >> + >> + >> +Example: >> + >> +fsi-master { >> + compatible = "ibm,fsi-master-gpio", "ibm,fsi-master"; > > From the description, these should be mutually exclusive. Will change. Thanks for your input. > >> + clk-gpios = <&gpio 0>, <&gpio 6>; >> + data-gpios = <&gpio 1>, <&gpio 7>; >> + enable-gpios = <&gpio 2>, <&gpio 8>; >> + trans-gpios = <&gpio 3>, <&gpio 9>; >> + mux-gpios = <&gpio 4>, <&gpio 10>; >> +} >> -- >> 1.8.2.2 >>