This source file includes following definitions.
- adc_ts_measure
- vf50_ts_enable_touch_detection
- vf50_ts_irq_bh
- vf50_ts_open
- vf50_ts_close
- vf50_ts_get_gpiod
- vf50_ts_channel_release
- vf50_ts_probe
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10 #include <linux/delay.h>
11 #include <linux/err.h>
12 #include <linux/gpio.h>
13 #include <linux/gpio/consumer.h>
14 #include <linux/iio/consumer.h>
15 #include <linux/iio/types.h>
16 #include <linux/input.h>
17 #include <linux/interrupt.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/of.h>
21 #include <linux/pinctrl/consumer.h>
22 #include <linux/platform_device.h>
23 #include <linux/slab.h>
24 #include <linux/types.h>
25
26 #define DRIVER_NAME "colibri-vf50-ts"
27
28 #define VF_ADC_MAX ((1 << 12) - 1)
29
30 #define COLI_TOUCH_MIN_DELAY_US 1000
31 #define COLI_TOUCH_MAX_DELAY_US 2000
32 #define COLI_PULLUP_MIN_DELAY_US 10000
33 #define COLI_PULLUP_MAX_DELAY_US 11000
34 #define COLI_TOUCH_NO_OF_AVGS 5
35 #define COLI_TOUCH_REQ_ADC_CHAN 4
36
37 struct vf50_touch_device {
38 struct platform_device *pdev;
39 struct input_dev *ts_input;
40 struct iio_channel *channels;
41 struct gpio_desc *gpio_xp;
42 struct gpio_desc *gpio_xm;
43 struct gpio_desc *gpio_yp;
44 struct gpio_desc *gpio_ym;
45 int pen_irq;
46 int min_pressure;
47 bool stop_touchscreen;
48 };
49
50
51
52
53 static int adc_ts_measure(struct iio_channel *channel,
54 struct gpio_desc *plate_p, struct gpio_desc *plate_m)
55 {
56 int i, value = 0, val = 0;
57 int error;
58
59 gpiod_set_value(plate_p, 1);
60 gpiod_set_value(plate_m, 1);
61
62 usleep_range(COLI_TOUCH_MIN_DELAY_US, COLI_TOUCH_MAX_DELAY_US);
63
64 for (i = 0; i < COLI_TOUCH_NO_OF_AVGS; i++) {
65 error = iio_read_channel_raw(channel, &val);
66 if (error < 0) {
67 value = error;
68 goto error_iio_read;
69 }
70
71 value += val;
72 }
73
74 value /= COLI_TOUCH_NO_OF_AVGS;
75
76 error_iio_read:
77 gpiod_set_value(plate_p, 0);
78 gpiod_set_value(plate_m, 0);
79
80 return value;
81 }
82
83
84
85
86 static void vf50_ts_enable_touch_detection(struct vf50_touch_device *vf50_ts)
87 {
88
89 gpiod_set_value(vf50_ts->gpio_ym, 1);
90
91
92
93
94
95 pinctrl_pm_select_idle_state(&vf50_ts->pdev->dev);
96
97
98 usleep_range(COLI_PULLUP_MIN_DELAY_US, COLI_PULLUP_MAX_DELAY_US);
99 }
100
101
102
103
104 static irqreturn_t vf50_ts_irq_bh(int irq, void *private)
105 {
106 struct vf50_touch_device *vf50_ts = private;
107 struct device *dev = &vf50_ts->pdev->dev;
108 int val_x, val_y, val_z1, val_z2, val_p = 0;
109 bool discard_val_on_start = true;
110
111
112 gpiod_set_value(vf50_ts->gpio_ym, 0);
113
114
115 pinctrl_pm_select_default_state(dev);
116
117 while (!vf50_ts->stop_touchscreen) {
118
119 val_x = adc_ts_measure(&vf50_ts->channels[0],
120 vf50_ts->gpio_xp, vf50_ts->gpio_xm);
121 if (val_x < 0)
122 break;
123
124
125 val_y = adc_ts_measure(&vf50_ts->channels[1],
126 vf50_ts->gpio_yp, vf50_ts->gpio_ym);
127 if (val_y < 0)
128 break;
129
130
131
132
133
134 val_z1 = adc_ts_measure(&vf50_ts->channels[2],
135 vf50_ts->gpio_yp, vf50_ts->gpio_xm);
136 if (val_z1 < 0)
137 break;
138 val_z2 = adc_ts_measure(&vf50_ts->channels[3],
139 vf50_ts->gpio_yp, vf50_ts->gpio_xm);
140 if (val_z2 < 0)
141 break;
142
143
144 if (val_z1 > 64 && val_x > 64) {
145
146
147
148
149 int r_x = (1000 * val_x) / VF_ADC_MAX;
150
151 val_p = (r_x * val_z2) / val_z1 - r_x;
152
153 } else {
154 val_p = 2000;
155 }
156
157 val_p = 2000 - val_p;
158 dev_dbg(dev,
159 "Measured values: x: %d, y: %d, z1: %d, z2: %d, p: %d\n",
160 val_x, val_y, val_z1, val_z2, val_p);
161
162
163
164
165
166 if (val_p < vf50_ts->min_pressure || val_p > 2000)
167 break;
168
169
170
171
172
173
174
175 if (discard_val_on_start) {
176 discard_val_on_start = false;
177 } else {
178
179
180
181
182 input_report_abs(vf50_ts->ts_input,
183 ABS_X, VF_ADC_MAX - val_x);
184 input_report_abs(vf50_ts->ts_input,
185 ABS_Y, VF_ADC_MAX - val_y);
186 input_report_abs(vf50_ts->ts_input,
187 ABS_PRESSURE, val_p);
188 input_report_key(vf50_ts->ts_input, BTN_TOUCH, 1);
189 input_sync(vf50_ts->ts_input);
190 }
191
192 usleep_range(COLI_PULLUP_MIN_DELAY_US,
193 COLI_PULLUP_MAX_DELAY_US);
194 }
195
196
197 input_report_abs(vf50_ts->ts_input, ABS_PRESSURE, 0);
198 input_report_key(vf50_ts->ts_input, BTN_TOUCH, 0);
199 input_sync(vf50_ts->ts_input);
200
201 vf50_ts_enable_touch_detection(vf50_ts);
202
203 return IRQ_HANDLED;
204 }
205
206 static int vf50_ts_open(struct input_dev *dev_input)
207 {
208 struct vf50_touch_device *touchdev = input_get_drvdata(dev_input);
209 struct device *dev = &touchdev->pdev->dev;
210
211 dev_dbg(dev, "Input device %s opened, starting touch detection\n",
212 dev_input->name);
213
214 touchdev->stop_touchscreen = false;
215
216
217 vf50_ts_enable_touch_detection(touchdev);
218
219 return 0;
220 }
221
222 static void vf50_ts_close(struct input_dev *dev_input)
223 {
224 struct vf50_touch_device *touchdev = input_get_drvdata(dev_input);
225 struct device *dev = &touchdev->pdev->dev;
226
227 touchdev->stop_touchscreen = true;
228
229
230 mb();
231 synchronize_irq(touchdev->pen_irq);
232
233 gpiod_set_value(touchdev->gpio_ym, 0);
234 pinctrl_pm_select_default_state(dev);
235
236 dev_dbg(dev, "Input device %s closed, disable touch detection\n",
237 dev_input->name);
238 }
239
240 static int vf50_ts_get_gpiod(struct device *dev, struct gpio_desc **gpio_d,
241 const char *con_id, enum gpiod_flags flags)
242 {
243 int error;
244
245 *gpio_d = devm_gpiod_get(dev, con_id, flags);
246 if (IS_ERR(*gpio_d)) {
247 error = PTR_ERR(*gpio_d);
248 dev_err(dev, "Could not get gpio_%s %d\n", con_id, error);
249 return error;
250 }
251
252 return 0;
253 }
254
255 static void vf50_ts_channel_release(void *data)
256 {
257 struct iio_channel *channels = data;
258
259 iio_channel_release_all(channels);
260 }
261
262 static int vf50_ts_probe(struct platform_device *pdev)
263 {
264 struct input_dev *input;
265 struct iio_channel *channels;
266 struct device *dev = &pdev->dev;
267 struct vf50_touch_device *touchdev;
268 int num_adc_channels;
269 int error;
270
271 channels = iio_channel_get_all(dev);
272 if (IS_ERR(channels))
273 return PTR_ERR(channels);
274
275 error = devm_add_action(dev, vf50_ts_channel_release, channels);
276 if (error) {
277 iio_channel_release_all(channels);
278 dev_err(dev, "Failed to register iio channel release action");
279 return error;
280 }
281
282 num_adc_channels = 0;
283 while (channels[num_adc_channels].indio_dev)
284 num_adc_channels++;
285
286 if (num_adc_channels != COLI_TOUCH_REQ_ADC_CHAN) {
287 dev_err(dev, "Inadequate ADC channels specified\n");
288 return -EINVAL;
289 }
290
291 touchdev = devm_kzalloc(dev, sizeof(*touchdev), GFP_KERNEL);
292 if (!touchdev)
293 return -ENOMEM;
294
295 touchdev->pdev = pdev;
296 touchdev->channels = channels;
297
298 error = of_property_read_u32(dev->of_node, "vf50-ts-min-pressure",
299 &touchdev->min_pressure);
300 if (error)
301 return error;
302
303 input = devm_input_allocate_device(dev);
304 if (!input) {
305 dev_err(dev, "Failed to allocate TS input device\n");
306 return -ENOMEM;
307 }
308
309 input->name = DRIVER_NAME;
310 input->id.bustype = BUS_HOST;
311 input->dev.parent = dev;
312 input->open = vf50_ts_open;
313 input->close = vf50_ts_close;
314
315 input_set_capability(input, EV_KEY, BTN_TOUCH);
316 input_set_abs_params(input, ABS_X, 0, VF_ADC_MAX, 0, 0);
317 input_set_abs_params(input, ABS_Y, 0, VF_ADC_MAX, 0, 0);
318 input_set_abs_params(input, ABS_PRESSURE, 0, VF_ADC_MAX, 0, 0);
319
320 touchdev->ts_input = input;
321 input_set_drvdata(input, touchdev);
322
323 error = input_register_device(input);
324 if (error) {
325 dev_err(dev, "Failed to register input device\n");
326 return error;
327 }
328
329 error = vf50_ts_get_gpiod(dev, &touchdev->gpio_xp, "xp", GPIOD_OUT_LOW);
330 if (error)
331 return error;
332
333 error = vf50_ts_get_gpiod(dev, &touchdev->gpio_xm,
334 "xm", GPIOD_OUT_LOW);
335 if (error)
336 return error;
337
338 error = vf50_ts_get_gpiod(dev, &touchdev->gpio_yp, "yp", GPIOD_OUT_LOW);
339 if (error)
340 return error;
341
342 error = vf50_ts_get_gpiod(dev, &touchdev->gpio_ym, "ym", GPIOD_OUT_LOW);
343 if (error)
344 return error;
345
346 touchdev->pen_irq = platform_get_irq(pdev, 0);
347 if (touchdev->pen_irq < 0)
348 return touchdev->pen_irq;
349
350 error = devm_request_threaded_irq(dev, touchdev->pen_irq,
351 NULL, vf50_ts_irq_bh, IRQF_ONESHOT,
352 "vf50 touch", touchdev);
353 if (error) {
354 dev_err(dev, "Failed to request IRQ %d: %d\n",
355 touchdev->pen_irq, error);
356 return error;
357 }
358
359 return 0;
360 }
361
362 static const struct of_device_id vf50_touch_of_match[] = {
363 { .compatible = "toradex,vf50-touchscreen", },
364 { }
365 };
366 MODULE_DEVICE_TABLE(of, vf50_touch_of_match);
367
368 static struct platform_driver vf50_touch_driver = {
369 .driver = {
370 .name = "toradex,vf50_touchctrl",
371 .of_match_table = vf50_touch_of_match,
372 },
373 .probe = vf50_ts_probe,
374 };
375 module_platform_driver(vf50_touch_driver);
376
377 MODULE_AUTHOR("Sanchayan Maity");
378 MODULE_DESCRIPTION("Colibri VF50 Touchscreen driver");
379 MODULE_LICENSE("GPL");