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 	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 
63 static 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 
68 static 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 
119 err:
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 
127 static 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 
158 static 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 
205 done:
206 	tps6507x_adc_standby(tsc);
207 }
208 
209 static 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 
294 err_free_polled_dev:
295 	input_free_polled_device(poll_dev);
296 err_free_mem:
297 	kfree(tsc);
298 	return error;
299 }
300 
301 static 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 
314 static struct platform_driver tps6507x_ts_driver = {
315 	.driver = {
316 		.name = "tps6507x-ts",
317 		.owner = THIS_MODULE,
318 	},
319 	.probe = tps6507x_ts_probe,
320 	.remove = tps6507x_ts_remove,
321 };
322 module_platform_driver(tps6507x_ts_driver);
323 
324 MODULE_AUTHOR("Todd Fischer <todd.fischer@ridgerun.com>");
325 MODULE_DESCRIPTION("TPS6507x - TouchScreen driver");
326 MODULE_LICENSE("GPL v2");
327 MODULE_ALIAS("platform:tps6507x-ts");
328