Author | Tokens | Token Proportion | Commits | Commit Proportion |
---|---|---|---|---|
Eugen Hristev | 854 | 100.00% | 1 | 100.00% |
Total | 854 | 1 |
// SPDX-License-Identifier: GPL-2.0 /* * ADC generic resistive touchscreen (GRTS) * This is a generic input driver that connects to an ADC * given the channels in device tree, and reports events to the input * subsystem. * * Copyright (C) 2017,2018 Microchip Technology, * Author: Eugen Hristev <eugen.hristev@microchip.com> * */ #include <linux/input.h> #include <linux/input/touchscreen.h> #include <linux/iio/consumer.h> #include <linux/iio/iio.h> #include <linux/module.h> #include <linux/of.h> #include <linux/of_device.h> #include <linux/platform_device.h> #define DRIVER_NAME "resistive-adc-touch" #define GRTS_DEFAULT_PRESSURE_MIN 50000 #define GRTS_MAX_POS_MASK GENMASK(11, 0) /** * grts_state - generic resistive touch screen information struct * @pressure_min: number representing the minimum 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 * @prop: touchscreen properties struct */ struct grts_state { u32 pressure_min; bool pressure; struct iio_channel *iio_chans; struct iio_cb_buffer *iio_cb; struct input_dev *input; struct touchscreen_properties prop; }; static int grts_cb(const void *data, void *private) { const u16 *touch_info = data; struct grts_state *st = private; unsigned int x, y, press = 0x0; /* 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_min))) { /* report end of touch */ input_report_key(st->input, BTN_TOUCH, 0); input_sync(st->input); return 0; } /* report proper touch to subsystem*/ touchscreen_report_pos(st->input, &st->prop, x, y, false); if (st->pressure) input_report_abs(st->input, ABS_PRESSURE, press); input_report_key(st->input, BTN_TOUCH, 1); input_sync(st->input); return 0; } static int grts_open(struct input_dev *dev) { int error; struct grts_state *st = input_get_drvdata(dev); error = iio_channel_start_all_cb(st->iio_cb); if (error) { dev_err(dev->dev.parent, "failed to start callback buffer.\n"); return error; } 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 void grts_disable(void *data) { iio_channel_release_all_cb(data); } static int grts_probe(struct platform_device *pdev) { struct grts_state *st; struct input_dev *input; struct device *dev = &pdev->dev; struct iio_channel *chan; int error; st = devm_kzalloc(dev, sizeof(struct grts_state), GFP_KERNEL); if (!st) return -ENOMEM; /* get the channels from IIO device */ st->iio_chans = devm_iio_channel_get_all(dev); if (IS_ERR(st->iio_chans)) { error = PTR_ERR(st->iio_chans); if (error != -EPROBE_DEFER) dev_err(dev, "can't get iio channels.\n"); return error; } chan = &st->iio_chans[0]; st->pressure = false; while (chan && chan->indio_dev) { if (!strcmp(chan->channel->datasheet_name, "pressure")) st->pressure = true; chan++; } if (st->pressure) { error = device_property_read_u32(dev, "touchscreen-min-pressure", &st->pressure_min); if (error) { dev_dbg(dev, "can't get touchscreen-min-pressure property.\n"); st->pressure_min = GRTS_DEFAULT_PRESSURE_MIN; } } 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->open = grts_open; input->close = grts_close; input_set_abs_params(input, ABS_X, 0, GRTS_MAX_POS_MASK - 1, 0, 0); input_set_abs_params(input, ABS_Y, 0, GRTS_MAX_POS_MASK - 1, 0, 0); if (st->pressure) input_set_abs_params(input, ABS_PRESSURE, st->pressure_min, 0xffff, 0, 0); input_set_capability(input, EV_KEY, BTN_TOUCH); /* parse optional device tree properties */ touchscreen_parse_properties(input, false, &st->prop); st->input = input; input_set_drvdata(input, st); error = input_register_device(input); if (error) { dev_err(dev, "failed to register input device."); return error; } st->iio_cb = iio_channel_get_all_cb(dev, grts_cb, st); if (IS_ERR(st->iio_cb)) { dev_err(dev, "failed to allocate callback buffer.\n"); return PTR_ERR(st->iio_cb); } error = devm_add_action_or_reset(dev, grts_disable, st->iio_cb); if (error) { dev_err(dev, "failed to add disable action.\n"); return error; } return 0; } static const struct of_device_id grts_of_match[] = { { .compatible = "resistive-adc-touch", }, { /* sentinel */ }, }; MODULE_DEVICE_TABLE(of, grts_of_match); static struct platform_driver grts_driver = { .probe = grts_probe, .driver = { .name = DRIVER_NAME, .of_match_table = of_match_ptr(grts_of_match), }, }; module_platform_driver(grts_driver); MODULE_AUTHOR("Eugen Hristev <eugen.hristev@microchip.com>"); MODULE_DESCRIPTION("Generic ADC Resistive Touch Driver"); MODULE_LICENSE("GPL v2");
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