From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Lechner Subject: [PATCH 0/4] new driver for TI eQEP Date: Mon, 22 Jul 2019 10:45:34 -0500 Message-ID: <20190722154538.5314-1-david@lechnology.com> Return-path: Sender: linux-kernel-owner@vger.kernel.org To: linux-iio@vger.kernel.org, linux-omap@vger.kernel.org, devicetree@vger.kernel.org Cc: David Lechner , Rob Herring , Mark Rutland , =?UTF-8?q?Beno=C3=AEt=20Cousson?= , Tony Lindgren , William Breathitt Gray , Thierry Reding , linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org List-Id: devicetree@vger.kernel.org This series adds device tree bindings and a new counter driver for the Texas Instruments Enhanced Quadrature Encoder Pulse (eQEP). As mentioned in one of the commit messages, to start with, the driver only supports reading the current counter value and setting the min/max values. Other features can be added on an as-needed basis. The only other feature I am interested in is adding is getting time data in order to calculate the rotational speed of a motor. However, there probably needs to be a higher level discussion of how this can fit into the counter subsystem in general first. This series has been tested on a BeagleBone Blue with the following script: #!/usr/bin/env python3 from os import path from time import sleep COUNTER_PATH = '/sys/bus/counter/devices' COUNTERS = ['counter0', 'counter1', 'counter2'] COUNT0 = 'count0' COUNT = 'count' CEILING = 'ceiling' FLOOR = 'floor' ENABLE = 'enable' cnts = [] for c in COUNTERS: enable_path = path.join(COUNTER_PATH, c, COUNT0, ENABLE) with open(enable_path, 'w') as f: f.write('1') ceiling_path = path.join(COUNTER_PATH, c, COUNT0, CEILING) with open(ceiling_path, 'w') as f: f.write(str(0xffffffff)) cnt_path = path.join(COUNTER_PATH, c, COUNT0, COUNT) cnts.append(open(cnt_path, 'r')) while True: for c in cnts: c.seek(0) val = int(c.read()) if val >= 0x80000000: val -= 0x100000000 print(val, end=' ') print() sleep(1) David Lechner (4): dt-bindings: counter: new bindings for TI eQEP counter: new TI eQEP driver ARM: dts: am33xx: Add nodes for eQEP ARM: dts: am335x-boneblue: Enable eQEP .../devicetree/bindings/counter/ti-eqep.txt | 18 + MAINTAINERS | 6 + arch/arm/boot/dts/am335x-boneblue.dts | 54 +++ arch/arm/boot/dts/am33xx-l4.dtsi | 27 ++ drivers/counter/Kconfig | 12 + drivers/counter/Makefile | 1 + drivers/counter/ti-eqep.c | 381 ++++++++++++++++++ drivers/pwm/Kconfig | 2 +- 8 files changed, 500 insertions(+), 1 deletion(-) create mode 100644 Documentation/devicetree/bindings/counter/ti-eqep.txt create mode 100644 drivers/counter/ti-eqep.c -- 2.17.1