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/drivers/input/touchscreen/tps6507x-ts.c

http://github.com/mirrors/linux
C | 294 lines | 214 code | 53 blank | 27 comment | 25 complexity | 20fcfed2c7112af37f7bf7d2bbf4c7f5 MD5 | raw file
  1/*
  2 * Touchscreen driver for the tps6507x chip.
  3 *
  4 * Copyright (c) 2009 RidgeRun (todd.fischer@ridgerun.com)
  5 *
  6 * Credits:
  7 *
  8 *    Using code from tsc2007, MtekVision Co., Ltd.
  9 *
 10 * For licencing details see kernel-base/COPYING
 11 *
 12 * TPS65070, TPS65073, TPS650731, and TPS650732 support
 13 * 10 bit touch screen interface.
 14 */
 15
 16#include <linux/module.h>
 17#include <linux/workqueue.h>
 18#include <linux/slab.h>
 19#include <linux/input.h>
 20#include <linux/platform_device.h>
 21#include <linux/mfd/tps6507x.h>
 22#include <linux/input/tps6507x-ts.h>
 23#include <linux/delay.h>
 24
 25#define TSC_DEFAULT_POLL_PERIOD 30 /* ms */
 26#define TPS_DEFAULT_MIN_PRESSURE 0x30
 27#define MAX_10BIT ((1 << 10) - 1)
 28
 29#define	TPS6507X_ADCONFIG_CONVERT_TS (TPS6507X_ADCONFIG_AD_ENABLE | \
 30					 TPS6507X_ADCONFIG_START_CONVERSION | \
 31					 TPS6507X_ADCONFIG_INPUT_REAL_TSC)
 32#define	TPS6507X_ADCONFIG_POWER_DOWN_TS (TPS6507X_ADCONFIG_INPUT_REAL_TSC)
 33
 34struct ts_event {
 35	u16	x;
 36	u16	y;
 37	u16	pressure;
 38};
 39
 40struct tps6507x_ts {
 41	struct device		*dev;
 42	struct input_dev	*input;
 43	struct tps6507x_dev	*mfd;
 44	char			phys[32];
 45	struct ts_event		tc;
 46	u16			min_pressure;
 47	bool			pendown;
 48};
 49
 50static int tps6507x_read_u8(struct tps6507x_ts *tsc, u8 reg, u8 *data)
 51{
 52	return tsc->mfd->read_dev(tsc->mfd, reg, 1, data);
 53}
 54
 55static int tps6507x_write_u8(struct tps6507x_ts *tsc, u8 reg, u8 data)
 56{
 57	return tsc->mfd->write_dev(tsc->mfd, reg, 1, &data);
 58}
 59
 60static s32 tps6507x_adc_conversion(struct tps6507x_ts *tsc,
 61				   u8 tsc_mode, u16 *value)
 62{
 63	s32 ret;
 64	u8 adc_status;
 65	u8 result;
 66
 67	/* Route input signal to A/D converter */
 68
 69	ret = tps6507x_write_u8(tsc, TPS6507X_REG_TSCMODE, tsc_mode);
 70	if (ret) {
 71		dev_err(tsc->dev, "TSC mode read failed\n");
 72		goto err;
 73	}
 74
 75	/* Start A/D conversion */
 76
 77	ret = tps6507x_write_u8(tsc, TPS6507X_REG_ADCONFIG,
 78				TPS6507X_ADCONFIG_CONVERT_TS);
 79	if (ret) {
 80		dev_err(tsc->dev, "ADC config write failed\n");
 81		return ret;
 82	}
 83
 84	do {
 85		ret = tps6507x_read_u8(tsc, TPS6507X_REG_ADCONFIG,
 86				       &adc_status);
 87		if (ret) {
 88			dev_err(tsc->dev, "ADC config read failed\n");
 89			goto err;
 90		}
 91	} while (adc_status & TPS6507X_ADCONFIG_START_CONVERSION);
 92
 93	ret = tps6507x_read_u8(tsc, TPS6507X_REG_ADRESULT_2, &result);
 94	if (ret) {
 95		dev_err(tsc->dev, "ADC result 2 read failed\n");
 96		goto err;
 97	}
 98
 99	*value = (result & TPS6507X_REG_ADRESULT_2_MASK) << 8;
100
101	ret = tps6507x_read_u8(tsc, TPS6507X_REG_ADRESULT_1, &result);
102	if (ret) {
103		dev_err(tsc->dev, "ADC result 1 read failed\n");
104		goto err;
105	}
106
107	*value |= result;
108
109	dev_dbg(tsc->dev, "TSC channel %d = 0x%X\n", tsc_mode, *value);
110
111err:
112	return ret;
113}
114
115/* Need to call tps6507x_adc_standby() after using A/D converter for the
116 * touch screen interrupt to work properly.
117 */
118
119static s32 tps6507x_adc_standby(struct tps6507x_ts *tsc)
120{
121	s32 ret;
122	s32 loops = 0;
123	u8 val;
124
125	ret = tps6507x_write_u8(tsc,  TPS6507X_REG_ADCONFIG,
126				TPS6507X_ADCONFIG_INPUT_TSC);
127	if (ret)
128		return ret;
129
130	ret = tps6507x_write_u8(tsc, TPS6507X_REG_TSCMODE,
131				TPS6507X_TSCMODE_STANDBY);
132	if (ret)
133		return ret;
134
135	ret = tps6507x_read_u8(tsc, TPS6507X_REG_INT, &val);
136	if (ret)
137		return ret;
138
139	while (val & TPS6507X_REG_TSC_INT) {
140		mdelay(10);
141		ret = tps6507x_read_u8(tsc, TPS6507X_REG_INT, &val);
142		if (ret)
143			return ret;
144		loops++;
145	}
146
147	return ret;
148}
149
150static void tps6507x_ts_poll(struct input_dev *input_dev)
151{
152	struct tps6507x_ts *tsc = input_get_drvdata(input_dev);
153	bool pendown;
154	s32 ret;
155
156	ret = tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_PRESSURE,
157				      &tsc->tc.pressure);
158	if (ret)
159		goto done;
160
161	pendown = tsc->tc.pressure > tsc->min_pressure;
162
163	if (unlikely(!pendown && tsc->pendown)) {
164		dev_dbg(tsc->dev, "UP\n");
165		input_report_key(input_dev, BTN_TOUCH, 0);
166		input_report_abs(input_dev, ABS_PRESSURE, 0);
167		input_sync(input_dev);
168		tsc->pendown = false;
169	}
170
171	if (pendown) {
172
173		if (!tsc->pendown) {
174			dev_dbg(tsc->dev, "DOWN\n");
175			input_report_key(input_dev, BTN_TOUCH, 1);
176		} else
177			dev_dbg(tsc->dev, "still down\n");
178
179		ret =  tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_X_POSITION,
180					       &tsc->tc.x);
181		if (ret)
182			goto done;
183
184		ret =  tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_Y_POSITION,
185					       &tsc->tc.y);
186		if (ret)
187			goto done;
188
189		input_report_abs(input_dev, ABS_X, tsc->tc.x);
190		input_report_abs(input_dev, ABS_Y, tsc->tc.y);
191		input_report_abs(input_dev, ABS_PRESSURE, tsc->tc.pressure);
192		input_sync(input_dev);
193		tsc->pendown = true;
194	}
195
196done:
197	tps6507x_adc_standby(tsc);
198}
199
200static int tps6507x_ts_probe(struct platform_device *pdev)
201{
202	struct tps6507x_dev *tps6507x_dev = dev_get_drvdata(pdev->dev.parent);
203	const struct tps6507x_board *tps_board;
204	const struct touchscreen_init_data *init_data;
205	struct tps6507x_ts *tsc;
206	struct input_dev *input_dev;
207	int error;
208
209	/*
210	 * tps_board points to pmic related constants
211	 * coming from the board-evm file.
212	 */
213	tps_board = dev_get_platdata(tps6507x_dev->dev);
214	if (!tps_board) {
215		dev_err(tps6507x_dev->dev,
216			"Could not find tps6507x platform data\n");
217		return -ENODEV;
218	}
219
220	/*
221	 * init_data points to array of regulator_init structures
222	 * coming from the board-evm file.
223	 */
224	init_data = tps_board->tps6507x_ts_init_data;
225
226	tsc = devm_kzalloc(&pdev->dev, sizeof(struct tps6507x_ts), GFP_KERNEL);
227	if (!tsc) {
228		dev_err(tps6507x_dev->dev, "failed to allocate driver data\n");
229		return -ENOMEM;
230	}
231
232	tsc->mfd = tps6507x_dev;
233	tsc->dev = tps6507x_dev->dev;
234	tsc->min_pressure = init_data ?
235			init_data->min_pressure : TPS_DEFAULT_MIN_PRESSURE;
236
237	snprintf(tsc->phys, sizeof(tsc->phys),
238		 "%s/input0", dev_name(tsc->dev));
239
240	input_dev = devm_input_allocate_device(&pdev->dev);
241	if (!input_dev) {
242		dev_err(tsc->dev, "Failed to allocate polled input device.\n");
243		return -ENOMEM;
244	}
245
246	tsc->input = input_dev;
247	input_set_drvdata(input_dev, tsc);
248
249	input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
250	input_set_abs_params(input_dev, ABS_X, 0, MAX_10BIT, 0, 0);
251	input_set_abs_params(input_dev, ABS_Y, 0, MAX_10BIT, 0, 0);
252	input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_10BIT, 0, 0);
253
254	input_dev->name = "TPS6507x Touchscreen";
255	input_dev->phys = tsc->phys;
256	input_dev->dev.parent = tsc->dev;
257	input_dev->id.bustype = BUS_I2C;
258	if (init_data) {
259		input_dev->id.vendor = init_data->vendor;
260		input_dev->id.product = init_data->product;
261		input_dev->id.version = init_data->version;
262	}
263
264	error = tps6507x_adc_standby(tsc);
265	if (error)
266		return error;
267
268	error = input_setup_polling(input_dev, tps6507x_ts_poll);
269	if (error)
270		return error;
271
272	input_set_poll_interval(input_dev,
273				init_data ? init_data->poll_period :
274					    TSC_DEFAULT_POLL_PERIOD);
275
276	error = input_register_device(input_dev);
277	if (error)
278		return error;
279
280	return 0;
281}
282
283static struct platform_driver tps6507x_ts_driver = {
284	.driver = {
285		.name = "tps6507x-ts",
286	},
287	.probe = tps6507x_ts_probe,
288};
289module_platform_driver(tps6507x_ts_driver);
290
291MODULE_AUTHOR("Todd Fischer <todd.fischer@ridgerun.com>");
292MODULE_DESCRIPTION("TPS6507x - TouchScreen driver");
293MODULE_LICENSE("GPL v2");
294MODULE_ALIAS("platform:tps6507x-ts");