mirror of https://gitee.com/openkylin/linux.git
205 lines
5.0 KiB
C
205 lines
5.0 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* ADC generic resistive touchscreen (GRTS)
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* This is a generic input driver that connects to an ADC
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* given the channels in device tree, and reports events to the input
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* subsystem.
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*
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* Copyright (C) 2017,2018 Microchip Technology,
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* Author: Eugen Hristev <eugen.hristev@microchip.com>
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*
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*/
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#include <linux/input.h>
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#include <linux/input/touchscreen.h>
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#include <linux/iio/consumer.h>
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#include <linux/iio/iio.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#define DRIVER_NAME "resistive-adc-touch"
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#define GRTS_DEFAULT_PRESSURE_MIN 50000
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#define GRTS_MAX_POS_MASK GENMASK(11, 0)
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/**
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* grts_state - generic resistive touch screen information struct
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* @pressure_min: number representing the minimum for the pressure
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* @pressure: are we getting pressure info or not
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* @iio_chans: list of channels acquired
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* @iio_cb: iio_callback buffer for the data
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* @input: the input device structure that we register
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* @prop: touchscreen properties struct
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*/
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struct grts_state {
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u32 pressure_min;
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bool pressure;
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struct iio_channel *iio_chans;
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struct iio_cb_buffer *iio_cb;
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struct input_dev *input;
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struct touchscreen_properties prop;
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};
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static int grts_cb(const void *data, void *private)
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{
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const u16 *touch_info = data;
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struct grts_state *st = private;
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unsigned int x, y, press = 0x0;
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/* channel data coming in buffer in the order below */
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x = touch_info[0];
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y = touch_info[1];
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if (st->pressure)
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press = touch_info[2];
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if ((!x && !y) || (st->pressure && (press < st->pressure_min))) {
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/* report end of touch */
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input_report_key(st->input, BTN_TOUCH, 0);
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input_sync(st->input);
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return 0;
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}
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/* report proper touch to subsystem*/
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touchscreen_report_pos(st->input, &st->prop, x, y, false);
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if (st->pressure)
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input_report_abs(st->input, ABS_PRESSURE, press);
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input_report_key(st->input, BTN_TOUCH, 1);
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input_sync(st->input);
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return 0;
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}
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static int grts_open(struct input_dev *dev)
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{
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int error;
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struct grts_state *st = input_get_drvdata(dev);
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error = iio_channel_start_all_cb(st->iio_cb);
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if (error) {
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dev_err(dev->dev.parent, "failed to start callback buffer.\n");
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return error;
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}
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return 0;
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}
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static void grts_close(struct input_dev *dev)
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{
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struct grts_state *st = input_get_drvdata(dev);
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iio_channel_stop_all_cb(st->iio_cb);
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}
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static void grts_disable(void *data)
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{
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iio_channel_release_all_cb(data);
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}
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static int grts_probe(struct platform_device *pdev)
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{
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struct grts_state *st;
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struct input_dev *input;
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struct device *dev = &pdev->dev;
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struct iio_channel *chan;
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int error;
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st = devm_kzalloc(dev, sizeof(struct grts_state), GFP_KERNEL);
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if (!st)
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return -ENOMEM;
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/* get the channels from IIO device */
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st->iio_chans = devm_iio_channel_get_all(dev);
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if (IS_ERR(st->iio_chans)) {
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error = PTR_ERR(st->iio_chans);
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if (error != -EPROBE_DEFER)
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dev_err(dev, "can't get iio channels.\n");
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return error;
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}
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chan = &st->iio_chans[0];
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st->pressure = false;
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while (chan && chan->indio_dev) {
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if (!strcmp(chan->channel->datasheet_name, "pressure"))
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st->pressure = true;
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chan++;
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}
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if (st->pressure) {
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error = device_property_read_u32(dev,
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"touchscreen-min-pressure",
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&st->pressure_min);
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if (error) {
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dev_dbg(dev, "can't get touchscreen-min-pressure property.\n");
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st->pressure_min = GRTS_DEFAULT_PRESSURE_MIN;
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}
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}
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input = devm_input_allocate_device(dev);
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if (!input) {
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dev_err(dev, "failed to allocate input device.\n");
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return -ENOMEM;
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}
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input->name = DRIVER_NAME;
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input->id.bustype = BUS_HOST;
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input->open = grts_open;
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input->close = grts_close;
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input_set_abs_params(input, ABS_X, 0, GRTS_MAX_POS_MASK - 1, 0, 0);
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input_set_abs_params(input, ABS_Y, 0, GRTS_MAX_POS_MASK - 1, 0, 0);
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if (st->pressure)
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input_set_abs_params(input, ABS_PRESSURE, st->pressure_min,
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0xffff, 0, 0);
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input_set_capability(input, EV_KEY, BTN_TOUCH);
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/* parse optional device tree properties */
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touchscreen_parse_properties(input, false, &st->prop);
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st->input = input;
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input_set_drvdata(input, st);
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error = input_register_device(input);
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if (error) {
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dev_err(dev, "failed to register input device.");
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return error;
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}
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st->iio_cb = iio_channel_get_all_cb(dev, grts_cb, st);
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if (IS_ERR(st->iio_cb)) {
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dev_err(dev, "failed to allocate callback buffer.\n");
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return PTR_ERR(st->iio_cb);
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}
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error = devm_add_action_or_reset(dev, grts_disable, st->iio_cb);
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if (error) {
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dev_err(dev, "failed to add disable action.\n");
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return error;
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}
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return 0;
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}
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static const struct of_device_id grts_of_match[] = {
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{
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.compatible = "resistive-adc-touch",
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}, {
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/* sentinel */
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},
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};
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MODULE_DEVICE_TABLE(of, grts_of_match);
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static struct platform_driver grts_driver = {
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.probe = grts_probe,
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.driver = {
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.name = DRIVER_NAME,
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.of_match_table = of_match_ptr(grts_of_match),
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},
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};
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module_platform_driver(grts_driver);
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MODULE_AUTHOR("Eugen Hristev <eugen.hristev@microchip.com>");
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MODULE_DESCRIPTION("Generic ADC Resistive Touch Driver");
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MODULE_LICENSE("GPL v2");
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