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14#include <linux/delay.h>
15#include <linux/err.h>
16#include <linux/gpio.h>
17#include <linux/gpio/consumer.h>
18#include <linux/iio/consumer.h>
19#include <linux/iio/types.h>
20#include <linux/input.h>
21#include <linux/interrupt.h>
22#include <linux/kernel.h>
23#include <linux/module.h>
24#include <linux/of.h>
25#include <linux/pinctrl/consumer.h>
26#include <linux/platform_device.h>
27#include <linux/slab.h>
28#include <linux/types.h>
29
30#define DRIVER_NAME "colibri-vf50-ts"
31#define DRV_VERSION "1.0"
32
33#define VF_ADC_MAX ((1 << 12) - 1)
34
35#define COLI_TOUCH_MIN_DELAY_US 1000
36#define COLI_TOUCH_MAX_DELAY_US 2000
37#define COLI_PULLUP_MIN_DELAY_US 10000
38#define COLI_PULLUP_MAX_DELAY_US 11000
39#define COLI_TOUCH_NO_OF_AVGS 5
40#define COLI_TOUCH_REQ_ADC_CHAN 4
41
42struct vf50_touch_device {
43 struct platform_device *pdev;
44 struct input_dev *ts_input;
45 struct iio_channel *channels;
46 struct gpio_desc *gpio_xp;
47 struct gpio_desc *gpio_xm;
48 struct gpio_desc *gpio_yp;
49 struct gpio_desc *gpio_ym;
50 int pen_irq;
51 int min_pressure;
52 bool stop_touchscreen;
53};
54
55
56
57
58static int adc_ts_measure(struct iio_channel *channel,
59 struct gpio_desc *plate_p, struct gpio_desc *plate_m)
60{
61 int i, value = 0, val = 0;
62 int error;
63
64 gpiod_set_value(plate_p, 1);
65 gpiod_set_value(plate_m, 1);
66
67 usleep_range(COLI_TOUCH_MIN_DELAY_US, COLI_TOUCH_MAX_DELAY_US);
68
69 for (i = 0; i < COLI_TOUCH_NO_OF_AVGS; i++) {
70 error = iio_read_channel_raw(channel, &val);
71 if (error < 0) {
72 value = error;
73 goto error_iio_read;
74 }
75
76 value += val;
77 }
78
79 value /= COLI_TOUCH_NO_OF_AVGS;
80
81error_iio_read:
82 gpiod_set_value(plate_p, 0);
83 gpiod_set_value(plate_m, 0);
84
85 return value;
86}
87
88
89
90
91static void vf50_ts_enable_touch_detection(struct vf50_touch_device *vf50_ts)
92{
93
94 gpiod_set_value(vf50_ts->gpio_ym, 1);
95
96
97
98
99
100 pinctrl_pm_select_idle_state(&vf50_ts->pdev->dev);
101
102
103 usleep_range(COLI_PULLUP_MIN_DELAY_US, COLI_PULLUP_MAX_DELAY_US);
104}
105
106
107
108
109static irqreturn_t vf50_ts_irq_bh(int irq, void *private)
110{
111 struct vf50_touch_device *vf50_ts = private;
112 struct device *dev = &vf50_ts->pdev->dev;
113 int val_x, val_y, val_z1, val_z2, val_p = 0;
114 bool discard_val_on_start = true;
115
116
117 gpiod_set_value(vf50_ts->gpio_ym, 0);
118
119
120 pinctrl_pm_select_default_state(dev);
121
122 while (!vf50_ts->stop_touchscreen) {
123
124 val_x = adc_ts_measure(&vf50_ts->channels[0],
125 vf50_ts->gpio_xp, vf50_ts->gpio_xm);
126 if (val_x < 0)
127 break;
128
129
130 val_y = adc_ts_measure(&vf50_ts->channels[1],
131 vf50_ts->gpio_yp, vf50_ts->gpio_ym);
132 if (val_y < 0)
133 break;
134
135
136
137
138
139 val_z1 = adc_ts_measure(&vf50_ts->channels[2],
140 vf50_ts->gpio_yp, vf50_ts->gpio_xm);
141 if (val_z1 < 0)
142 break;
143 val_z2 = adc_ts_measure(&vf50_ts->channels[3],
144 vf50_ts->gpio_yp, vf50_ts->gpio_xm);
145 if (val_z2 < 0)
146 break;
147
148
149 if (val_z1 > 64 && val_x > 64) {
150
151
152
153
154 int r_x = (1000 * val_x) / VF_ADC_MAX;
155
156 val_p = (r_x * val_z2) / val_z1 - r_x;
157
158 } else {
159 val_p = 2000;
160 }
161
162 val_p = 2000 - val_p;
163 dev_dbg(dev,
164 "Measured values: x: %d, y: %d, z1: %d, z2: %d, p: %d\n",
165 val_x, val_y, val_z1, val_z2, val_p);
166
167
168
169
170
171 if (val_p < vf50_ts->min_pressure || val_p > 2000)
172 break;
173
174
175
176
177
178
179
180 if (discard_val_on_start) {
181 discard_val_on_start = false;
182 } else {
183
184
185
186
187 input_report_abs(vf50_ts->ts_input,
188 ABS_X, VF_ADC_MAX - val_x);
189 input_report_abs(vf50_ts->ts_input,
190 ABS_Y, VF_ADC_MAX - val_y);
191 input_report_abs(vf50_ts->ts_input,
192 ABS_PRESSURE, val_p);
193 input_report_key(vf50_ts->ts_input, BTN_TOUCH, 1);
194 input_sync(vf50_ts->ts_input);
195 }
196
197 usleep_range(COLI_PULLUP_MIN_DELAY_US,
198 COLI_PULLUP_MAX_DELAY_US);
199 }
200
201
202 input_report_abs(vf50_ts->ts_input, ABS_PRESSURE, 0);
203 input_report_key(vf50_ts->ts_input, BTN_TOUCH, 0);
204 input_sync(vf50_ts->ts_input);
205
206 vf50_ts_enable_touch_detection(vf50_ts);
207
208 return IRQ_HANDLED;
209}
210
211static int vf50_ts_open(struct input_dev *dev_input)
212{
213 struct vf50_touch_device *touchdev = input_get_drvdata(dev_input);
214 struct device *dev = &touchdev->pdev->dev;
215
216 dev_dbg(dev, "Input device %s opened, starting touch detection\n",
217 dev_input->name);
218
219 touchdev->stop_touchscreen = false;
220
221
222 vf50_ts_enable_touch_detection(touchdev);
223
224 return 0;
225}
226
227static void vf50_ts_close(struct input_dev *dev_input)
228{
229 struct vf50_touch_device *touchdev = input_get_drvdata(dev_input);
230 struct device *dev = &touchdev->pdev->dev;
231
232 touchdev->stop_touchscreen = true;
233
234
235 mb();
236 synchronize_irq(touchdev->pen_irq);
237
238 gpiod_set_value(touchdev->gpio_ym, 0);
239 pinctrl_pm_select_default_state(dev);
240
241 dev_dbg(dev, "Input device %s closed, disable touch detection\n",
242 dev_input->name);
243}
244
245static int vf50_ts_get_gpiod(struct device *dev, struct gpio_desc **gpio_d,
246 const char *con_id, enum gpiod_flags flags)
247{
248 int error;
249
250 *gpio_d = devm_gpiod_get(dev, con_id, flags);
251 if (IS_ERR(*gpio_d)) {
252 error = PTR_ERR(*gpio_d);
253 dev_err(dev, "Could not get gpio_%s %d\n", con_id, error);
254 return error;
255 }
256
257 return 0;
258}
259
260static void vf50_ts_channel_release(void *data)
261{
262 struct iio_channel *channels = data;
263
264 iio_channel_release_all(channels);
265}
266
267static int vf50_ts_probe(struct platform_device *pdev)
268{
269 struct input_dev *input;
270 struct iio_channel *channels;
271 struct device *dev = &pdev->dev;
272 struct vf50_touch_device *touchdev;
273 int num_adc_channels;
274 int error;
275
276 channels = iio_channel_get_all(dev);
277 if (IS_ERR(channels))
278 return PTR_ERR(channels);
279
280 error = devm_add_action(dev, vf50_ts_channel_release, channels);
281 if (error) {
282 iio_channel_release_all(channels);
283 dev_err(dev, "Failed to register iio channel release action");
284 return error;
285 }
286
287 num_adc_channels = 0;
288 while (channels[num_adc_channels].indio_dev)
289 num_adc_channels++;
290
291 if (num_adc_channels != COLI_TOUCH_REQ_ADC_CHAN) {
292 dev_err(dev, "Inadequate ADC channels specified\n");
293 return -EINVAL;
294 }
295
296 touchdev = devm_kzalloc(dev, sizeof(*touchdev), GFP_KERNEL);
297 if (!touchdev)
298 return -ENOMEM;
299
300 touchdev->pdev = pdev;
301 touchdev->channels = channels;
302
303 error = of_property_read_u32(dev->of_node, "vf50-ts-min-pressure",
304 &touchdev->min_pressure);
305 if (error)
306 return error;
307
308 input = devm_input_allocate_device(dev);
309 if (!input) {
310 dev_err(dev, "Failed to allocate TS input device\n");
311 return -ENOMEM;
312 }
313
314 input->name = DRIVER_NAME;
315 input->id.bustype = BUS_HOST;
316 input->dev.parent = dev;
317 input->open = vf50_ts_open;
318 input->close = vf50_ts_close;
319
320 input_set_capability(input, EV_KEY, BTN_TOUCH);
321 input_set_abs_params(input, ABS_X, 0, VF_ADC_MAX, 0, 0);
322 input_set_abs_params(input, ABS_Y, 0, VF_ADC_MAX, 0, 0);
323 input_set_abs_params(input, ABS_PRESSURE, 0, VF_ADC_MAX, 0, 0);
324
325 touchdev->ts_input = input;
326 input_set_drvdata(input, touchdev);
327
328 error = input_register_device(input);
329 if (error) {
330 dev_err(dev, "Failed to register input device\n");
331 return error;
332 }
333
334 error = vf50_ts_get_gpiod(dev, &touchdev->gpio_xp, "xp", GPIOD_OUT_LOW);
335 if (error)
336 return error;
337
338 error = vf50_ts_get_gpiod(dev, &touchdev->gpio_xm,
339 "xm", GPIOD_OUT_LOW);
340 if (error)
341 return error;
342
343 error = vf50_ts_get_gpiod(dev, &touchdev->gpio_yp, "yp", GPIOD_OUT_LOW);
344 if (error)
345 return error;
346
347 error = vf50_ts_get_gpiod(dev, &touchdev->gpio_ym, "ym", GPIOD_OUT_LOW);
348 if (error)
349 return error;
350
351 touchdev->pen_irq = platform_get_irq(pdev, 0);
352 if (touchdev->pen_irq < 0)
353 return touchdev->pen_irq;
354
355 error = devm_request_threaded_irq(dev, touchdev->pen_irq,
356 NULL, vf50_ts_irq_bh, IRQF_ONESHOT,
357 "vf50 touch", touchdev);
358 if (error) {
359 dev_err(dev, "Failed to request IRQ %d: %d\n",
360 touchdev->pen_irq, error);
361 return error;
362 }
363
364 return 0;
365}
366
367static const struct of_device_id vf50_touch_of_match[] = {
368 { .compatible = "toradex,vf50-touchscreen", },
369 { }
370};
371MODULE_DEVICE_TABLE(of, vf50_touch_of_match);
372
373static struct platform_driver vf50_touch_driver = {
374 .driver = {
375 .name = "toradex,vf50_touchctrl",
376 .of_match_table = vf50_touch_of_match,
377 },
378 .probe = vf50_ts_probe,
379};
380module_platform_driver(vf50_touch_driver);
381
382MODULE_AUTHOR("Sanchayan Maity");
383MODULE_DESCRIPTION("Colibri VF50 Touchscreen driver");
384MODULE_LICENSE("GPL");
385MODULE_VERSION(DRV_VERSION);
386
