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
35struct ts_event {
36 u16 x;
37 u16 y;
38 u16 pressure;
39};
40
41struct 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
51static 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
56static 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
61static 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
112err:
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
120static 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
151static 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
198done:
199 tps6507x_adc_standby(tsc);
200}
201
202static 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
285static struct platform_driver tps6507x_ts_driver = {
286 .driver = {
287 .name = "tps6507x-ts",
288 },
289 .probe = tps6507x_ts_probe,
290};
291module_platform_driver(tps6507x_ts_driver);
292
293MODULE_AUTHOR("Todd Fischer <todd.fischer@ridgerun.com>");
294MODULE_DESCRIPTION("TPS6507x - TouchScreen driver");
295MODULE_LICENSE("GPL v2");
296MODULE_ALIAS("platform:tps6507x-ts");
297