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/input-polldev.h>
21#include <linux/platform_device.h>
22#include <linux/mfd/tps6507x.h>
23#include <linux/input/tps6507x-ts.h>
24#include <linux/delay.h>
25
26#define TSC_DEFAULT_POLL_PERIOD 30 /* ms */
27#define TPS_DEFAULT_MIN_PRESSURE 0x30
28#define MAX_10BIT ((1 << 10) - 1)
29
30#define	TPS6507X_ADCONFIG_CONVERT_TS (TPS6507X_ADCONFIG_AD_ENABLE | \
31					 TPS6507X_ADCONFIG_START_CONVERSION | \
32					 TPS6507X_ADCONFIG_INPUT_REAL_TSC)
33#define	TPS6507X_ADCONFIG_POWER_DOWN_TS (TPS6507X_ADCONFIG_INPUT_REAL_TSC)
34
35struct ts_event {
36	u16	x;
37	u16	y;
38	u16	pressure;
39};
40
41struct tps6507x_ts {
42	struct device		*dev;
43	struct input_polled_dev	*poll_dev;
44	struct tps6507x_dev	*mfd;
45	char			phys[32];
46	struct ts_event		tc;
47	u16			min_pressure;
48	bool			pendown;
49};
50
51static int tps6507x_read_u8(struct tps6507x_ts *tsc, u8 reg, u8 *data)
52{
53	int err;
54
55	err = tsc->mfd->read_dev(tsc->mfd, reg, 1, data);
56
57	if (err)
58		return err;
59
60	return 0;
61}
62
63static int tps6507x_write_u8(struct tps6507x_ts *tsc, u8 reg, u8 data)
64{
65	return tsc->mfd->write_dev(tsc->mfd, reg, 1, &data);
66}
67
68static s32 tps6507x_adc_conversion(struct tps6507x_ts *tsc,
69				   u8 tsc_mode, u16 *value)
70{
71	s32 ret;
72	u8 adc_status;
73	u8 result;
74
75	/* Route input signal to A/D converter */
76
77	ret = tps6507x_write_u8(tsc, TPS6507X_REG_TSCMODE, tsc_mode);
78	if (ret) {
79		dev_err(tsc->dev, "TSC mode read failed\n");
80		goto err;
81	}
82
83	/* Start A/D conversion */
84
85	ret = tps6507x_write_u8(tsc, TPS6507X_REG_ADCONFIG,
86				TPS6507X_ADCONFIG_CONVERT_TS);
87	if (ret) {
88		dev_err(tsc->dev, "ADC config write failed\n");
89		return ret;
90	}
91
92	do {
93		ret = tps6507x_read_u8(tsc, TPS6507X_REG_ADCONFIG,
94				       &adc_status);
95		if (ret) {
96			dev_err(tsc->dev, "ADC config read failed\n");
97			goto err;
98		}
99	} while (adc_status & TPS6507X_ADCONFIG_START_CONVERSION);
100
101	ret = tps6507x_read_u8(tsc, TPS6507X_REG_ADRESULT_2, &result);
102	if (ret) {
103		dev_err(tsc->dev, "ADC result 2 read failed\n");
104		goto err;
105	}
106
107	*value = (result & TPS6507X_REG_ADRESULT_2_MASK) << 8;
108
109	ret = tps6507x_read_u8(tsc, TPS6507X_REG_ADRESULT_1, &result);
110	if (ret) {
111		dev_err(tsc->dev, "ADC result 1 read failed\n");
112		goto err;
113	}
114
115	*value |= result;
116
117	dev_dbg(tsc->dev, "TSC channel %d = 0x%X\n", tsc_mode, *value);
118
119err:
120	return ret;
121}
122
123/* Need to call tps6507x_adc_standby() after using A/D converter for the
124 * touch screen interrupt to work properly.
125 */
126
127static s32 tps6507x_adc_standby(struct tps6507x_ts *tsc)
128{
129	s32 ret;
130	s32 loops = 0;
131	u8 val;
132
133	ret = tps6507x_write_u8(tsc,  TPS6507X_REG_ADCONFIG,
134				TPS6507X_ADCONFIG_INPUT_TSC);
135	if (ret)
136		return ret;
137
138	ret = tps6507x_write_u8(tsc, TPS6507X_REG_TSCMODE,
139				TPS6507X_TSCMODE_STANDBY);
140	if (ret)
141		return ret;
142
143	ret = tps6507x_read_u8(tsc, TPS6507X_REG_INT, &val);
144	if (ret)
145		return ret;
146
147	while (val & TPS6507X_REG_TSC_INT) {
148		mdelay(10);
149		ret = tps6507x_read_u8(tsc, TPS6507X_REG_INT, &val);
150		if (ret)
151			return ret;
152		loops++;
153	}
154
155	return ret;
156}
157
158static void tps6507x_ts_poll(struct input_polled_dev *poll_dev)
159{
160	struct tps6507x_ts *tsc = poll_dev->private;
161	struct input_dev *input_dev = poll_dev->input;
162	bool pendown;
163	s32 ret;
164
165	ret = tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_PRESSURE,
166				      &tsc->tc.pressure);
167	if (ret)
168		goto done;
169
170	pendown = tsc->tc.pressure > tsc->min_pressure;
171
172	if (unlikely(!pendown && tsc->pendown)) {
173		dev_dbg(tsc->dev, "UP\n");
174		input_report_key(input_dev, BTN_TOUCH, 0);
175		input_report_abs(input_dev, ABS_PRESSURE, 0);
176		input_sync(input_dev);
177		tsc->pendown = false;
178	}
179
180	if (pendown) {
181
182		if (!tsc->pendown) {
183			dev_dbg(tsc->dev, "DOWN\n");
184			input_report_key(input_dev, BTN_TOUCH, 1);
185		} else
186			dev_dbg(tsc->dev, "still down\n");
187
188		ret =  tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_X_POSITION,
189					       &tsc->tc.x);
190		if (ret)
191			goto done;
192
193		ret =  tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_Y_POSITION,
194					       &tsc->tc.y);
195		if (ret)
196			goto done;
197
198		input_report_abs(input_dev, ABS_X, tsc->tc.x);
199		input_report_abs(input_dev, ABS_Y, tsc->tc.y);
200		input_report_abs(input_dev, ABS_PRESSURE, tsc->tc.pressure);
201		input_sync(input_dev);
202		tsc->pendown = true;
203	}
204
205done:
206	tps6507x_adc_standby(tsc);
207}
208
209static int tps6507x_ts_probe(struct platform_device *pdev)
210{
211	struct tps6507x_dev *tps6507x_dev = dev_get_drvdata(pdev->dev.parent);
212	const struct tps6507x_board *tps_board;
213	const struct touchscreen_init_data *init_data;
214	struct tps6507x_ts *tsc;
215	struct input_polled_dev *poll_dev;
216	struct input_dev *input_dev;
217	int error;
218
219	/*
220	 * tps_board points to pmic related constants
221	 * coming from the board-evm file.
222	 */
223	tps_board = dev_get_platdata(tps6507x_dev->dev);
224	if (!tps_board) {
225		dev_err(tps6507x_dev->dev,
226			"Could not find tps6507x platform data\n");
227		return -ENODEV;
228	}
229
230	/*
231	 * init_data points to array of regulator_init structures
232	 * coming from the board-evm file.
233	 */
234	init_data = tps_board->tps6507x_ts_init_data;
235
236	tsc = kzalloc(sizeof(struct tps6507x_ts), GFP_KERNEL);
237	if (!tsc) {
238		dev_err(tps6507x_dev->dev, "failed to allocate driver data\n");
239		return -ENOMEM;
240	}
241
242	tsc->mfd = tps6507x_dev;
243	tsc->dev = tps6507x_dev->dev;
244	tsc->min_pressure = init_data ?
245			init_data->min_pressure : TPS_DEFAULT_MIN_PRESSURE;
246
247	snprintf(tsc->phys, sizeof(tsc->phys),
248		 "%s/input0", dev_name(tsc->dev));
249
250	poll_dev = input_allocate_polled_device();
251	if (!poll_dev) {
252		dev_err(tsc->dev, "Failed to allocate polled input device.\n");
253		error = -ENOMEM;
254		goto err_free_mem;
255	}
256
257	tsc->poll_dev = poll_dev;
258
259	poll_dev->private = tsc;
260	poll_dev->poll = tps6507x_ts_poll;
261	poll_dev->poll_interval = init_data ?
262			init_data->poll_period : TSC_DEFAULT_POLL_PERIOD;
263
264	input_dev = poll_dev->input;
265	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
266	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
267
268	input_set_abs_params(input_dev, ABS_X, 0, MAX_10BIT, 0, 0);
269	input_set_abs_params(input_dev, ABS_Y, 0, MAX_10BIT, 0, 0);
270	input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_10BIT, 0, 0);
271
272	input_dev->name = "TPS6507x Touchscreen";
273	input_dev->phys = tsc->phys;
274	input_dev->dev.parent = tsc->dev;
275	input_dev->id.bustype = BUS_I2C;
276	if (init_data) {
277		input_dev->id.vendor = init_data->vendor;
278		input_dev->id.product = init_data->product;
279		input_dev->id.version = init_data->version;
280	}
281
282	error = tps6507x_adc_standby(tsc);
283	if (error)
284		goto err_free_polled_dev;
285
286	error = input_register_polled_device(poll_dev);
287	if (error)
288		goto err_free_polled_dev;
289
290	platform_set_drvdata(pdev, tsc);
291
292	return 0;
293
294err_free_polled_dev:
295	input_free_polled_device(poll_dev);
296err_free_mem:
297	kfree(tsc);
298	return error;
299}
300
301static int tps6507x_ts_remove(struct platform_device *pdev)
302{
303	struct tps6507x_ts *tsc = platform_get_drvdata(pdev);
304	struct input_polled_dev *poll_dev = tsc->poll_dev;
305
306	input_unregister_polled_device(poll_dev);
307	input_free_polled_device(poll_dev);
308
309	kfree(tsc);
310
311	return 0;
312}
313
314static struct platform_driver tps6507x_ts_driver = {
315	.driver = {
316		.name = "tps6507x-ts",
317	},
318	.probe = tps6507x_ts_probe,
319	.remove = tps6507x_ts_remove,
320};
321module_platform_driver(tps6507x_ts_driver);
322
323MODULE_AUTHOR("Todd Fischer <todd.fischer@ridgerun.com>");
324MODULE_DESCRIPTION("TPS6507x - TouchScreen driver");
325MODULE_LICENSE("GPL v2");
326MODULE_ALIAS("platform:tps6507x-ts");
327