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