1 // SPDX-License-Identifier: GPL-2.0
21 #define DRIVER_NAME					"resistive-adc-touch"
37  * struct grts_state - generic resistive touch screen information struct
39  * @pressure_min:	number representing the minimum for the pressure
40  * @pressure:		are we getting pressure info or not
50 	bool				pressure;  member
64 	x = touch_info[st->ch_map[GRTS_CH_X]];  in grts_cb()
65 	y = touch_info[st->ch_map[GRTS_CH_Y]];  in grts_cb()
67 	if (st->ch_map[GRTS_CH_PRESSURE] < GRTS_MAX_CHANNELS) {  in grts_cb()
68 		press = touch_info[st->ch_map[GRTS_CH_PRESSURE]];  in grts_cb()
69 	} else if (st->ch_map[GRTS_CH_Z1] < GRTS_MAX_CHANNELS) {  in grts_cb()
70 		unsigned int z1 = touch_info[st->ch_map[GRTS_CH_Z1]];  in grts_cb()
71 		unsigned int z2 = touch_info[st->ch_map[GRTS_CH_Z2]];  in grts_cb()
76 			Rt -= z1;  in grts_cb()
77 			Rt *= st->x_plate_ohms;  in grts_cb()
83 			 * On increased pressure the resistance (Rt) is  in grts_cb()
85 			 * real pressure.  in grts_cb()
88 				press = GRTS_DEFAULT_PRESSURE_MAX - Rt;  in grts_cb()
92 	if ((!x && !y) || (st->pressure && (press < st->pressure_min))) {  in grts_cb()
94 		input_report_key(st->input, BTN_TOUCH, 0);  in grts_cb()
95 		input_sync(st->input);  in grts_cb()
100 	touchscreen_report_pos(st->input, &st->prop, x, y, false);  in grts_cb()
101 	if (st->pressure)  in grts_cb()
102 		input_report_abs(st->input, ABS_PRESSURE, press);  in grts_cb()
103 	input_report_key(st->input, BTN_TOUCH, 1);  in grts_cb()
104 	input_sync(st->input);  in grts_cb()
114 	error = iio_channel_start_all_cb(st->iio_cb);  in grts_open()
116 		dev_err(dev->dev.parent, "failed to start callback buffer.\n");  in grts_open()
126 	iio_channel_stop_all_cb(st->iio_cb);  in grts_close()
140 	idx = device_property_match_string(dev, "io-channel-names", name);  in grts_map_channel()
146 		return -EOVERFLOW;  in grts_map_channel()
149 	st->ch_map[type] = idx;  in grts_map_channel()
165 	/* pressure is optional */  in grts_get_properties()
166 	error = grts_map_channel(st, dev, GRTS_CH_PRESSURE, "pressure", true);  in grts_get_properties()
170 	if (st->ch_map[GRTS_CH_PRESSURE] < GRTS_MAX_CHANNELS) {  in grts_get_properties()
171 		st->pressure = true;  in grts_get_properties()
175 	/* if no pressure is defined, try optional z1 + z2 */  in grts_get_properties()
180 	if (st->ch_map[GRTS_CH_Z1] >= GRTS_MAX_CHANNELS)  in grts_get_properties()
189 					 "touchscreen-x-plate-ohms",  in grts_get_properties()
190 					 &st->x_plate_ohms);  in grts_get_properties()
192 		dev_err(dev, "can't get touchscreen-x-plate-ohms property\n");  in grts_get_properties()
196 	st->pressure = true;  in grts_get_properties()
204 	struct device *dev = &pdev->dev;  in grts_probe()
209 		return -ENOMEM;  in grts_probe()
212 	st->iio_chans = devm_iio_channel_get_all(dev);  in grts_probe()
213 	if (IS_ERR(st->iio_chans))  in grts_probe()
214 		return dev_err_probe(dev, PTR_ERR(st->iio_chans), "can't get iio channels\n");  in grts_probe()
216 	if (!device_property_present(dev, "io-channel-names"))  in grts_probe()
217 		return -ENODEV;  in grts_probe()
225 	if (st->pressure) {  in grts_probe()
227 						 "touchscreen-min-pressure",  in grts_probe()
228 						 &st->pressure_min);  in grts_probe()
230 			dev_dbg(dev, "can't get touchscreen-min-pressure property.\n");  in grts_probe()
231 			st->pressure_min = GRTS_DEFAULT_PRESSURE_MIN;  in grts_probe()
238 		return -ENOMEM;  in grts_probe()
241 	input->name = DRIVER_NAME;  in grts_probe()
242 	input->id.bustype = BUS_HOST;  in grts_probe()
243 	input->open = grts_open;  in grts_probe()
244 	input->close = grts_close;  in grts_probe()
246 	input_set_abs_params(input, ABS_X, 0, GRTS_MAX_POS_MASK - 1, 0, 0);  in grts_probe()
247 	input_set_abs_params(input, ABS_Y, 0, GRTS_MAX_POS_MASK - 1, 0, 0);  in grts_probe()
248 	if (st->pressure)  in grts_probe()
249 		input_set_abs_params(input, ABS_PRESSURE, st->pressure_min,  in grts_probe()
255 	touchscreen_parse_properties(input, false, &st->prop);  in grts_probe()
257 	st->input = input;  in grts_probe()
266 	st->iio_cb = iio_channel_get_all_cb(dev, grts_cb, st);  in grts_probe()
267 	if (IS_ERR(st->iio_cb)) {  in grts_probe()
269 		return PTR_ERR(st->iio_cb);  in grts_probe()
272 	error = devm_add_action_or_reset(dev, grts_disable, st->iio_cb);  in grts_probe()
283 		.compatible = "resistive-adc-touch",