From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752536AbeC3M6q (ORCPT ); Fri, 30 Mar 2018 08:58:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:57022 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752349AbeC3M6l (ORCPT ); Fri, 30 Mar 2018 08:58:41 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 34E352175B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=jic23@kernel.org Date: Fri, 30 Mar 2018 13:58:35 +0100 From: Jonathan Cameron To: Eugen Hristev Cc: , , , , , , , , Subject: Re: [PATCH v2 07/10] input: touchscreen: touch_adc: add generic resistive ADC touchscreen Message-ID: <20180330135835.6a8f57f1@archlinux> In-Reply-To: <1522153963-1121-8-git-send-email-eugen.hristev@microchip.com> References: <1522153963-1121-1-git-send-email-eugen.hristev@microchip.com> <1522153963-1121-8-git-send-email-eugen.hristev@microchip.com> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 27 Mar 2018 15:32:40 +0300 Eugen Hristev wrote: > This adds a generic resistive touchscreen (GRTS) driver, which is based > on an IIO device (an ADC). It must be connected to the channels of an ADC > to receive touch data. Then it will feed the data into the input subsystem > where it registers an input device. > It uses an IIO callback buffer to register to the IIO device > > Some parts of this patch are based on initial original work by > Mohamed Jamsheeth Hajanajubudeen and Bandaru Venkateswara Swamy > > Signed-off-by: Eugen Hristev I like this a lot! A few minor bits and bobs inline. Over to Dmitry for the input side of things. Jonathan > --- > Changes in v2: > - this is now a generic resistive adc touchscreen driver > > drivers/input/touchscreen/Kconfig | 13 +++ > drivers/input/touchscreen/Makefile | 1 + > drivers/input/touchscreen/touch_adc.c | 199 ++++++++++++++++++++++++++++++++++ > 3 files changed, 213 insertions(+) > create mode 100644 drivers/input/touchscreen/touch_adc.c > > diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig > index 4f15496..afd879f 100644 > --- a/drivers/input/touchscreen/Kconfig > +++ b/drivers/input/touchscreen/Kconfig > @@ -92,6 +92,19 @@ config TOUCHSCREEN_AD7879_SPI > To compile this driver as a module, choose M here: the > module will be called ad7879-spi. > > +config TOUCHSCREEN_ADC > + tristate "Generic ADC based resistive touchscreen" > + depends on IIO > + select IIO_BUFFER_CB > + help > + Say Y here if you want to use the generic ADC > + resistive touchscreen driver. > + > + If unsure, say N (but it's safe to say "Y"). > + > + To compile this driver as a module, choose M here: the > + module will be called touch_adc.ko. > + > config TOUCHSCREEN_AR1021_I2C > tristate "Microchip AR1020/1021 i2c touchscreen" > depends on I2C && OF > diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile > index dddae79..cbe6121 100644 > --- a/drivers/input/touchscreen/Makefile > +++ b/drivers/input/touchscreen/Makefile > @@ -13,6 +13,7 @@ obj-$(CONFIG_TOUCHSCREEN_AD7877) += ad7877.o > obj-$(CONFIG_TOUCHSCREEN_AD7879) += ad7879.o > obj-$(CONFIG_TOUCHSCREEN_AD7879_I2C) += ad7879-i2c.o > obj-$(CONFIG_TOUCHSCREEN_AD7879_SPI) += ad7879-spi.o > +obj-$(CONFIG_TOUCHSCREEN_ADC) += touch_adc.o > obj-$(CONFIG_TOUCHSCREEN_ADS7846) += ads7846.o > obj-$(CONFIG_TOUCHSCREEN_AR1021_I2C) += ar1021_i2c.o > obj-$(CONFIG_TOUCHSCREEN_ATMEL_MXT) += atmel_mxt_ts.o > diff --git a/drivers/input/touchscreen/touch_adc.c b/drivers/input/touchscreen/touch_adc.c > new file mode 100644 > index 0000000..de4b929 > --- /dev/null > +++ b/drivers/input/touchscreen/touch_adc.c > @@ -0,0 +1,199 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * ADC generic resistive touchscreen (GRTS) > + * > + * Copyright (C) 2017,2018 Microchip Technology, > + * Author: Eugen Hristev > + * > + */ > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define DRIVER_NAME "touch_adc" > +#define GRTS_DEFAULT_PRESSURE_THRESHOLD 10000 > +#define MAX_POS_MASK GENMASK(11, 0) > + > +/** > + * grts_state - generic resistive touch screen information struct > + * @pressure_threshold: number representing the threshold for the pressure > + * @pressure: are we getting pressure info or not > + * @iio_chans: list of channels acquired > + * @iio_cb: iio_callback buffer for the data > + * @input: the input device structure that we register > + */ > +struct grts_state { > + u32 pressure_threshold; > + bool pressure; > + struct iio_channel *iio_chans; > + struct iio_cb_buffer *iio_cb; > + struct input_dev *input; > +}; > + > +static int grts_cb(const void *data, void *private) > +{ > + const u16 *touch_info = data; > + struct grts_state *st = private; > + > + unsigned int x, y, press = 0xFFFF; > + > + /* channel data coming in buffer in the order below */ > + x = touch_info[0]; > + y = touch_info[1]; > + if (st->pressure) > + press = touch_info[2]; > + > + if ((!x && !y) || (st->pressure && (press > st->pressure_threshold))) { Ah, clearly pressure is the other way around to I assumed and gets larger as the pressure is reduced. hmm. > + /* report end of touch */ > + input_report_key(st->input, BTN_TOUCH, 0); > + input_sync(st->input); > + return 0; > + } > + > + /* report proper touch to subsystem*/ > + input_report_abs(st->input, ABS_X, x); > + input_report_abs(st->input, ABS_Y, y); > + if (st->pressure) > + input_report_abs(st->input, ABS_PRESSURE, press); > + input_report_key(st->input, BTN_TOUCH, 1); > + input_sync(st->input); blank line preferred here. > + return 0; > +} > + > +static int grts_open(struct input_dev *dev) > +{ > + int ret; > + struct grts_state *st = input_get_drvdata(dev); > + > + ret = iio_channel_start_all_cb(st->iio_cb); > + if (ret) { > + dev_err(dev->dev.parent, "failed to start callback buffer.\n"); > + return ret; Drop the return ret out of the brackets. > + } > + return 0; > +} > + > +static void grts_close(struct input_dev *dev) > +{ > + struct grts_state *st = input_get_drvdata(dev); > + > + iio_channel_stop_all_cb(st->iio_cb); > +} > + > +static int grts_probe(struct platform_device *pdev) > +{ > + struct grts_state *st; > + struct input_dev *input; > + struct device *dev = &pdev->dev; > + struct device_node *node = dev->of_node; > + struct iio_channel *chan; > + int ret = 0; > + > + st = devm_kzalloc(dev, sizeof(struct grts_state), GFP_KERNEL); > + if (!st) > + return -ENOMEM; > + > + ret = of_property_read_u32(node, > + "generic-adc-resistive-touchscreen,pressure-threshold", > + &st->pressure_threshold); > + if (ret < 0) { > + dev_dbg(dev, "can't get touchscreen pressure threshold property.\n"); > + st->pressure_threshold = GRTS_DEFAULT_PRESSURE_THRESHOLD; > + } > + > + /* get the channels from IIO device */ > + st->iio_chans = devm_iio_channel_get_all(dev); > + > + if (IS_ERR(st->iio_chans)) { > + if (PTR_ERR(st->iio_chans) != -EPROBE_DEFER) > + dev_err(dev, "can't get iio channels.\n"); > + return PTR_ERR(st->iio_chans); > + } > + > + chan = &st->iio_chans[0]; > + st->pressure = false; > + while (chan && chan->indio_dev) { > + if (!strcmp(chan->channel->datasheet_name, "pressure")) > + st->pressure = true; > + chan++; > + } > + > + input = devm_input_allocate_device(dev); > + if (!input) { > + dev_err(dev, "failed to allocate input device.\n"); > + return -ENOMEM; > + } > + > + input->name = DRIVER_NAME; > + input->id.bustype = BUS_HOST; > + input->dev.parent = dev; > + input->open = grts_open; > + input->close = grts_close; > + > + input_set_abs_params(input, ABS_X, 0, MAX_POS_MASK - 1, 0, 0); > + input_set_abs_params(input, ABS_Y, 0, MAX_POS_MASK - 1, 0, 0); > + if (st->pressure) > + input_set_abs_params(input, ABS_PRESSURE, 0, 0xffffff, 0, 0); > + > + input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); > + input->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH); > + > + st->input = input; > + input_set_drvdata(input, st); > + > + ret = input_register_device(input); > + if (ret) { > + dev_err(dev, "failed to register input device."); > + return ret; > + } > + > + st->iio_cb = iio_channel_get_all_cb(&pdev->dev, grts_cb, st); > + > + if (IS_ERR(st->iio_cb)) { > + dev_err(dev, "failed to allocate callback buffer.\n"); > + ret = PTR_ERR(st->iio_cb); > + return ret; > + } > + > + platform_set_drvdata(pdev, st); > + > + return ret; > +} > + > +static int grts_remove(struct platform_device *pdev) > +{ > + struct grts_state *st = platform_get_drvdata(pdev); > + > + iio_channel_release_all_cb(st->iio_cb); > + input_unregister_device(st->input); blank line preferred before simple returns. > + return 0; > +} > + > +static const struct of_device_id grts_of_match[] = { > + { > + .compatible = "generic-resistive-adc-touch", > + }, { > + /* sentinel */ > + }, > +}; > + > +MODULE_DEVICE_TABLE(of, grts_of_match); > + > +static struct platform_driver grts_driver = { > + .probe = grts_probe, > + .remove = grts_remove, > + .driver = { > + .name = DRIVER_NAME, > + .of_match_table = of_match_ptr(grts_of_match), > + }, > +}; > + > +module_platform_driver(grts_driver); > + > +MODULE_AUTHOR("Eugen Hristev "); > +MODULE_DESCRIPTION("Generic ADC Resistive Touch Driver"); > +MODULE_LICENSE("GPL v2");