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 
34 struct ts_event {
35 	u16	x;
36 	u16	y;
37 	u16	pressure;
38 };
39 
40 struct 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 
tps6507x_read_u8(struct tps6507x_ts * tsc,u8 reg,u8 * data)50 static 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 
tps6507x_write_u8(struct tps6507x_ts * tsc,u8 reg,u8 data)55 static 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 
tps6507x_adc_conversion(struct tps6507x_ts * tsc,u8 tsc_mode,u16 * value)60 static 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 
111 err:
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 
tps6507x_adc_standby(struct tps6507x_ts * tsc)119 static 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 
tps6507x_ts_poll(struct input_dev * input_dev)148 static 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 
194 done:
195 	tps6507x_adc_standby(tsc);
196 }
197 
tps6507x_ts_probe(struct platform_device * pdev)198 static 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 
281 static struct platform_driver tps6507x_ts_driver = {
282 	.driver = {
283 		.name = "tps6507x-ts",
284 	},
285 	.probe = tps6507x_ts_probe,
286 };
287 module_platform_driver(tps6507x_ts_driver);
288 
289 MODULE_AUTHOR("Todd Fischer <todd.fischer@ridgerun.com>");
290 MODULE_DESCRIPTION("TPS6507x - TouchScreen driver");
291 MODULE_LICENSE("GPL v2");
292 MODULE_ALIAS("platform:tps6507x-ts");
293