From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E5BD9C433FF for ; Fri, 2 Aug 2019 16:17:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B809F20644 for ; Fri, 2 Aug 2019 16:17:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=lechnology.com header.i=@lechnology.com header.b="gv/Y1onS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390663AbfHBQRR (ORCPT ); Fri, 2 Aug 2019 12:17:17 -0400 Received: from vern.gendns.com ([98.142.107.122]:43374 "EHLO vern.gendns.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728853AbfHBQRO (ORCPT ); Fri, 2 Aug 2019 12:17:14 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lechnology.com; s=default; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=Xh1krsXQ4OmAr0IgdObgohDnJErEyjk90MXL/lKpUtU=; b=gv/Y1onS6VrRWH9/CW7Ne05LMF wJhlJRZa/KUY8yP3RquMvvTs6/O6A7lxwbHkyk3XGYXmHtpt6yFPBY26EuNU64NgiXhCDBqp6YPrH 8MFusQmZ+r9o+osnzLGO8PWtNFTGB2r+Hhp9s8vHwtbVmr9/qc0jTO+NRxZHmc4sIvz0mu3Hid2id k9WzyavVm4airyryyTmbwPq0eYvJjfBA+UQCwUYRO1hhNfDvNx+7s4rwmxnGvWKAxX+u9jxBYTO3J kwM5CYs5Oqbkf6ASOoGXYTCbSV8e3avp65xKQxjtesq0TPxxEH2n7CAxGoVGnS80fNqRgc3dqw0Yh XrVsq8PA==; Received: from 108-198-5-147.lightspeed.okcbok.sbcglobal.net ([108.198.5.147]:42876 helo=[192.168.0.134]) by vern.gendns.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.92) (envelope-from ) id 1htaEy-004w7U-Ps; Fri, 02 Aug 2019 12:17:12 -0400 Subject: Re: [PATCH 2/4] counter: new TI eQEP driver To: William Breathitt Gray Cc: linux-iio@vger.kernel.org, linux-omap@vger.kernel.org, devicetree@vger.kernel.org, Rob Herring , Mark Rutland , =?UTF-8?Q?Beno=c3=aet_Cousson?= , Tony Lindgren , Thierry Reding , linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org References: <20190722154538.5314-1-david@lechnology.com> <20190722154538.5314-3-david@lechnology.com> <20190802092727.GB30522@icarus> From: David Lechner Message-ID: <680ed555-c5db-6640-8fd3-121422077eff@lechnology.com> Date: Fri, 2 Aug 2019 11:17:11 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190802092727.GB30522@icarus> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - vern.gendns.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - lechnology.com X-Get-Message-Sender-Via: vern.gendns.com: authenticated_id: davidmain+lechnology.com/only user confirmed/virtual account not confirmed X-Authenticated-Sender: vern.gendns.com: davidmain@lechnology.com X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/2/19 4:27 AM, William Breathitt Gray wrote: >> +static const struct counter_ops ti_eqep_counter_ops = { >> + .count_read = ti_eqep_count_read, >> + .count_write = ti_eqep_count_write, >> + .function_get = ti_eqep_function_get, >> + .function_set = ti_eqep_function_set, >> +}; > Are you able to provide a signal_read function, or are the Signals not > exposed to the user by this device? Sometimes quadrature encoder devices > provide an instanteous read of the signal lines to tell whether they are > high or low, so I figured I'd ask. No, it does not look like these signals can be read directly. > > You should define an action_get function as well along with Synapses > corresponding to each Signal. This will allow users to know whether the > Synapse fires on a rising edge, falling edge, no edge, or both edges. > > For example, consider the drivers/counter/104-quad-8.c file. Each count > register has three associated signal lines: Quadrature A, Quadrature B, > and Index. > > Quadrature A and B are your typical quadrature encoder lines and > depending on the function mode selected (quadrature x4, pulse-direction, > etc.) could have a Synapse action mode of none, rising edge, falling > edge, or both edges; see the quad8_synapse_actions_list array. > > In contrast, the Index signal line only has two Synapse action modes: > rising edge (in the case preset functionality is enabled) or none. The encoders I have don't use the index or strobe signals, so I was thinking maybe I should omit those two signals from the driver for the time being since I don't have a way of testing. > > For the TI eQEP driver, there will be four Synapses corresponding to the > four Signals: QEPA, QEPB, QEPI, and QEPS. See if you are able to > implement the Synapses and action_get function by using the 104-quad-8.c > file as a reference. That file does have a lot of extra functionality > tossed in compared to yours, so if you have trouble groking it, just let > me know and I'll try to help. >