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	u8 val;
123
124	ret = tps6507x_write_u8(tsc,  TPS6507X_REG_ADCONFIG,
125				TPS6507X_ADCONFIG_INPUT_TSC);
126	if (ret)
127		return ret;
128
129	ret = tps6507x_write_u8(tsc, TPS6507X_REG_TSCMODE,
130				TPS6507X_TSCMODE_STANDBY);
131	if (ret)
132		return ret;
133
134	ret = tps6507x_read_u8(tsc, TPS6507X_REG_INT, &val);
135	if (ret)
136		return ret;
137
138	while (val & TPS6507X_REG_TSC_INT) {
139		mdelay(10);
140		ret = tps6507x_read_u8(tsc, TPS6507X_REG_INT, &val);
141		if (ret)
142			return ret;
143	}
144
145	return ret;
146}
147
148static void tps6507x_ts_poll(struct input_dev *input_dev)
149{
150	struct tps6507x_ts *tsc = input_get_drvdata(input_dev);
151	bool pendown;
152	s32 ret;
153
154	ret = tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_PRESSURE,
155				      &tsc->tc.pressure);
156	if (ret)
157		goto done;
158
159	pendown = tsc->tc.pressure > tsc->min_pressure;
160
161	if (unlikely(!pendown && tsc->pendown)) {
162		dev_dbg(tsc->dev, "UP\n");
163		input_report_key(input_dev, BTN_TOUCH, 0);
164		input_report_abs(input_dev, ABS_PRESSURE, 0);
165		input_sync(input_dev);
166		tsc->pendown = false;
167	}
168
169	if (pendown) {
170
171		if (!tsc->pendown) {
172			dev_dbg(tsc->dev, "DOWN\n");
173			input_report_key(input_dev, BTN_TOUCH, 1);
174		} else
175			dev_dbg(tsc->dev, "still down\n");
176
177		ret =  tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_X_POSITION,
178					       &tsc->tc.x);
179		if (ret)
180			goto done;
181
182		ret =  tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_Y_POSITION,
183					       &tsc->tc.y);
184		if (ret)
185			goto done;
186
187		input_report_abs(input_dev, ABS_X, tsc->tc.x);
188		input_report_abs(input_dev, ABS_Y, tsc->tc.y);
189		input_report_abs(input_dev, ABS_PRESSURE, tsc->tc.pressure);
190		input_sync(input_dev);
191		tsc->pendown = true;
192	}
193
194done:
195	tps6507x_adc_standby(tsc);
196}
197
198static int tps6507x_ts_probe(struct platform_device *pdev)
199{
200	struct tps6507x_dev *tps6507x_dev = dev_get_drvdata(pdev->dev.parent);
201	const struct tps6507x_board *tps_board;
202	const struct touchscreen_init_data *init_data;
203	struct tps6507x_ts *tsc;
204	struct input_dev *input_dev;
205	int error;
206
207	/*
208	 * tps_board points to pmic related constants
209	 * coming from the board-evm file.
210	 */
211	tps_board = dev_get_platdata(tps6507x_dev->dev);
212	if (!tps_board) {
213		dev_err(tps6507x_dev->dev,
214			"Could not find tps6507x platform data\n");
215		return -ENODEV;
216	}
217
218	/*
219	 * init_data points to array of regulator_init structures
220	 * coming from the board-evm file.
221	 */
222	init_data = tps_board->tps6507x_ts_init_data;
223
224	tsc = devm_kzalloc(&pdev->dev, sizeof(struct tps6507x_ts), GFP_KERNEL);
225	if (!tsc) {
226		dev_err(tps6507x_dev->dev, "failed to allocate driver data\n");
227		return -ENOMEM;
228	}
229
230	tsc->mfd = tps6507x_dev;
231	tsc->dev = tps6507x_dev->dev;
232	tsc->min_pressure = init_data ?
233			init_data->min_pressure : TPS_DEFAULT_MIN_PRESSURE;
234
235	snprintf(tsc->phys, sizeof(tsc->phys),
236		 "%s/input0", dev_name(tsc->dev));
237
238	input_dev = devm_input_allocate_device(&pdev->dev);
239	if (!input_dev) {
240		dev_err(tsc->dev, "Failed to allocate polled input device.\n");
241		return -ENOMEM;
242	}
243
244	tsc->input = input_dev;
245	input_set_drvdata(input_dev, tsc);
246
247	input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
248	input_set_abs_params(input_dev, ABS_X, 0, MAX_10BIT, 0, 0);
249	input_set_abs_params(input_dev, ABS_Y, 0, MAX_10BIT, 0, 0);
250	input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_10BIT, 0, 0);
251
252	input_dev->name = "TPS6507x Touchscreen";
253	input_dev->phys = tsc->phys;
254	input_dev->dev.parent = tsc->dev;
255	input_dev->id.bustype = BUS_I2C;
256	if (init_data) {
257		input_dev->id.vendor = init_data->vendor;
258		input_dev->id.product = init_data->product;
259		input_dev->id.version = init_data->version;
260	}
261
262	error = tps6507x_adc_standby(tsc);
263	if (error)
264		return error;
265
266	error = input_setup_polling(input_dev, tps6507x_ts_poll);
267	if (error)
268		return error;
269
270	input_set_poll_interval(input_dev,
271				init_data ? init_data->poll_period :
272					    TSC_DEFAULT_POLL_PERIOD);
273
274	error = input_register_device(input_dev);
275	if (error)
276		return error;
277
278	return 0;
279}
280
281static struct platform_driver tps6507x_ts_driver = {
282	.driver = {
283		.name = "tps6507x-ts",
284	},
285	.probe = tps6507x_ts_probe,
286};
287module_platform_driver(tps6507x_ts_driver);
288
289MODULE_AUTHOR("Todd Fischer <todd.fischer@ridgerun.com>");
290MODULE_DESCRIPTION("TPS6507x - TouchScreen driver");
291MODULE_LICENSE("GPL v2");
292MODULE_ALIAS("platform:tps6507x-ts");
293