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