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Linux/drivers/input/touchscreen/tsc2007.c

  1 /*
  2  * drivers/input/touchscreen/tsc2007.c
  3  *
  4  * Copyright (c) 2008 MtekVision Co., Ltd.
  5  *      Kwangwoo Lee <kwlee@mtekvision.com>
  6  *
  7  * Using code from:
  8  *  - ads7846.c
  9  *      Copyright (c) 2005 David Brownell
 10  *      Copyright (c) 2006 Nokia Corporation
 11  *  - corgi_ts.c
 12  *      Copyright (C) 2004-2005 Richard Purdie
 13  *  - omap_ts.[hc], ads7846.h, ts_osk.c
 14  *      Copyright (C) 2002 MontaVista Software
 15  *      Copyright (C) 2004 Texas Instruments
 16  *      Copyright (C) 2005 Dirk Behme
 17  *
 18  *  This program is free software; you can redistribute it and/or modify
 19  *  it under the terms of the GNU General Public License version 2 as
 20  *  published by the Free Software Foundation.
 21  */
 22 
 23 #include <linux/module.h>
 24 #include <linux/slab.h>
 25 #include <linux/input.h>
 26 #include <linux/interrupt.h>
 27 #include <linux/i2c.h>
 28 #include <linux/i2c/tsc2007.h>
 29 #include <linux/of_device.h>
 30 #include <linux/of.h>
 31 #include <linux/of_gpio.h>
 32 
 33 #define TSC2007_MEASURE_TEMP0           (0x0 << 4)
 34 #define TSC2007_MEASURE_AUX             (0x2 << 4)
 35 #define TSC2007_MEASURE_TEMP1           (0x4 << 4)
 36 #define TSC2007_ACTIVATE_XN             (0x8 << 4)
 37 #define TSC2007_ACTIVATE_YN             (0x9 << 4)
 38 #define TSC2007_ACTIVATE_YP_XN          (0xa << 4)
 39 #define TSC2007_SETUP                   (0xb << 4)
 40 #define TSC2007_MEASURE_X               (0xc << 4)
 41 #define TSC2007_MEASURE_Y               (0xd << 4)
 42 #define TSC2007_MEASURE_Z1              (0xe << 4)
 43 #define TSC2007_MEASURE_Z2              (0xf << 4)
 44 
 45 #define TSC2007_POWER_OFF_IRQ_EN        (0x0 << 2)
 46 #define TSC2007_ADC_ON_IRQ_DIS0         (0x1 << 2)
 47 #define TSC2007_ADC_OFF_IRQ_EN          (0x2 << 2)
 48 #define TSC2007_ADC_ON_IRQ_DIS1         (0x3 << 2)
 49 
 50 #define TSC2007_12BIT                   (0x0 << 1)
 51 #define TSC2007_8BIT                    (0x1 << 1)
 52 
 53 #define MAX_12BIT                       ((1 << 12) - 1)
 54 
 55 #define ADC_ON_12BIT    (TSC2007_12BIT | TSC2007_ADC_ON_IRQ_DIS0)
 56 
 57 #define READ_Y          (ADC_ON_12BIT | TSC2007_MEASURE_Y)
 58 #define READ_Z1         (ADC_ON_12BIT | TSC2007_MEASURE_Z1)
 59 #define READ_Z2         (ADC_ON_12BIT | TSC2007_MEASURE_Z2)
 60 #define READ_X          (ADC_ON_12BIT | TSC2007_MEASURE_X)
 61 #define PWRDOWN         (TSC2007_12BIT | TSC2007_POWER_OFF_IRQ_EN)
 62 
 63 struct ts_event {
 64         u16     x;
 65         u16     y;
 66         u16     z1, z2;
 67 };
 68 
 69 struct tsc2007 {
 70         struct input_dev        *input;
 71         char                    phys[32];
 72 
 73         struct i2c_client       *client;
 74 
 75         u16                     model;
 76         u16                     x_plate_ohms;
 77         u16                     max_rt;
 78         unsigned long           poll_period; /* in jiffies */
 79         int                     fuzzx;
 80         int                     fuzzy;
 81         int                     fuzzz;
 82 
 83         unsigned                gpio;
 84         int                     irq;
 85 
 86         wait_queue_head_t       wait;
 87         bool                    stopped;
 88 
 89         int                     (*get_pendown_state)(struct device *);
 90         void                    (*clear_penirq)(void);
 91 };
 92 
 93 static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
 94 {
 95         s32 data;
 96         u16 val;
 97 
 98         data = i2c_smbus_read_word_data(tsc->client, cmd);
 99         if (data < 0) {
100                 dev_err(&tsc->client->dev, "i2c io error: %d\n", data);
101                 return data;
102         }
103 
104         /* The protocol and raw data format from i2c interface:
105          * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P
106          * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit].
107          */
108         val = swab16(data) >> 4;
109 
110         dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val);
111 
112         return val;
113 }
114 
115 static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
116 {
117         /* y- still on; turn on only y+ (and ADC) */
118         tc->y = tsc2007_xfer(tsc, READ_Y);
119 
120         /* turn y- off, x+ on, then leave in lowpower */
121         tc->x = tsc2007_xfer(tsc, READ_X);
122 
123         /* turn y+ off, x- on; we'll use formula #1 */
124         tc->z1 = tsc2007_xfer(tsc, READ_Z1);
125         tc->z2 = tsc2007_xfer(tsc, READ_Z2);
126 
127         /* Prepare for next touch reading - power down ADC, enable PENIRQ */
128         tsc2007_xfer(tsc, PWRDOWN);
129 }
130 
131 static u32 tsc2007_calculate_pressure(struct tsc2007 *tsc, struct ts_event *tc)
132 {
133         u32 rt = 0;
134 
135         /* range filtering */
136         if (tc->x == MAX_12BIT)
137                 tc->x = 0;
138 
139         if (likely(tc->x && tc->z1)) {
140                 /* compute touch pressure resistance using equation #1 */
141                 rt = tc->z2 - tc->z1;
142                 rt *= tc->x;
143                 rt *= tsc->x_plate_ohms;
144                 rt /= tc->z1;
145                 rt = (rt + 2047) >> 12;
146         }
147 
148         return rt;
149 }
150 
151 static bool tsc2007_is_pen_down(struct tsc2007 *ts)
152 {
153         /*
154          * NOTE: We can't rely on the pressure to determine the pen down
155          * state, even though this controller has a pressure sensor.
156          * The pressure value can fluctuate for quite a while after
157          * lifting the pen and in some cases may not even settle at the
158          * expected value.
159          *
160          * The only safe way to check for the pen up condition is in the
161          * work function by reading the pen signal state (it's a GPIO
162          * and IRQ). Unfortunately such callback is not always available,
163          * in that case we assume that the pen is down and expect caller
164          * to fall back on the pressure reading.
165          */
166 
167         if (!ts->get_pendown_state)
168                 return true;
169 
170         return ts->get_pendown_state(&ts->client->dev);
171 }
172 
173 static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
174 {
175         struct tsc2007 *ts = handle;
176         struct input_dev *input = ts->input;
177         struct ts_event tc;
178         u32 rt;
179 
180         while (!ts->stopped && tsc2007_is_pen_down(ts)) {
181 
182                 /* pen is down, continue with the measurement */
183                 tsc2007_read_values(ts, &tc);
184 
185                 rt = tsc2007_calculate_pressure(ts, &tc);
186 
187                 if (!rt && !ts->get_pendown_state) {
188                         /*
189                          * If pressure reported is 0 and we don't have
190                          * callback to check pendown state, we have to
191                          * assume that pen was lifted up.
192                          */
193                         break;
194                 }
195 
196                 if (rt <= ts->max_rt) {
197                         dev_dbg(&ts->client->dev,
198                                 "DOWN point(%4d,%4d), pressure (%4u)\n",
199                                 tc.x, tc.y, rt);
200 
201                         input_report_key(input, BTN_TOUCH, 1);
202                         input_report_abs(input, ABS_X, tc.x);
203                         input_report_abs(input, ABS_Y, tc.y);
204                         input_report_abs(input, ABS_PRESSURE, rt);
205 
206                         input_sync(input);
207 
208                 } else {
209                         /*
210                          * Sample found inconsistent by debouncing or pressure is
211                          * beyond the maximum. Don't report it to user space,
212                          * repeat at least once more the measurement.
213                          */
214                         dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
215                 }
216 
217                 wait_event_timeout(ts->wait, ts->stopped, ts->poll_period);
218         }
219 
220         dev_dbg(&ts->client->dev, "UP\n");
221 
222         input_report_key(input, BTN_TOUCH, 0);
223         input_report_abs(input, ABS_PRESSURE, 0);
224         input_sync(input);
225 
226         if (ts->clear_penirq)
227                 ts->clear_penirq();
228 
229         return IRQ_HANDLED;
230 }
231 
232 static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
233 {
234         struct tsc2007 *ts = handle;
235 
236         if (tsc2007_is_pen_down(ts))
237                 return IRQ_WAKE_THREAD;
238 
239         if (ts->clear_penirq)
240                 ts->clear_penirq();
241 
242         return IRQ_HANDLED;
243 }
244 
245 static void tsc2007_stop(struct tsc2007 *ts)
246 {
247         ts->stopped = true;
248         mb();
249         wake_up(&ts->wait);
250 
251         disable_irq(ts->irq);
252 }
253 
254 static int tsc2007_open(struct input_dev *input_dev)
255 {
256         struct tsc2007 *ts = input_get_drvdata(input_dev);
257         int err;
258 
259         ts->stopped = false;
260         mb();
261 
262         enable_irq(ts->irq);
263 
264         /* Prepare for touch readings - power down ADC and enable PENIRQ */
265         err = tsc2007_xfer(ts, PWRDOWN);
266         if (err < 0) {
267                 tsc2007_stop(ts);
268                 return err;
269         }
270 
271         return 0;
272 }
273 
274 static void tsc2007_close(struct input_dev *input_dev)
275 {
276         struct tsc2007 *ts = input_get_drvdata(input_dev);
277 
278         tsc2007_stop(ts);
279 }
280 
281 #ifdef CONFIG_OF
282 static int tsc2007_get_pendown_state_gpio(struct device *dev)
283 {
284         struct i2c_client *client = to_i2c_client(dev);
285         struct tsc2007 *ts = i2c_get_clientdata(client);
286 
287         return !gpio_get_value(ts->gpio);
288 }
289 
290 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
291 {
292         struct device_node *np = client->dev.of_node;
293         u32 val32;
294         u64 val64;
295 
296         if (!np) {
297                 dev_err(&client->dev, "missing device tree data\n");
298                 return -EINVAL;
299         }
300 
301         if (!of_property_read_u32(np, "ti,max-rt", &val32))
302                 ts->max_rt = val32;
303         else
304                 ts->max_rt = MAX_12BIT;
305 
306         if (!of_property_read_u32(np, "ti,fuzzx", &val32))
307                 ts->fuzzx = val32;
308 
309         if (!of_property_read_u32(np, "ti,fuzzy", &val32))
310                 ts->fuzzy = val32;
311 
312         if (!of_property_read_u32(np, "ti,fuzzz", &val32))
313                 ts->fuzzz = val32;
314 
315         if (!of_property_read_u64(np, "ti,poll-period", &val64))
316                 ts->poll_period = msecs_to_jiffies(val64);
317         else
318                 ts->poll_period = msecs_to_jiffies(1);
319 
320         if (!of_property_read_u32(np, "ti,x-plate-ohms", &val32)) {
321                 ts->x_plate_ohms = val32;
322         } else {
323                 dev_err(&client->dev, "missing ti,x-plate-ohms devicetree property.");
324                 return -EINVAL;
325         }
326 
327         ts->gpio = of_get_gpio(np, 0);
328         if (gpio_is_valid(ts->gpio))
329                 ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
330         else
331                 dev_warn(&client->dev,
332                          "GPIO not specified in DT (of_get_gpio returned %d)\n",
333                          ts->gpio);
334 
335         return 0;
336 }
337 #else
338 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
339 {
340         dev_err(&client->dev, "platform data is required!\n");
341         return -EINVAL;
342 }
343 #endif
344 
345 static int tsc2007_probe_pdev(struct i2c_client *client, struct tsc2007 *ts,
346                               const struct tsc2007_platform_data *pdata,
347                               const struct i2c_device_id *id)
348 {
349         ts->model             = pdata->model;
350         ts->x_plate_ohms      = pdata->x_plate_ohms;
351         ts->max_rt            = pdata->max_rt ? : MAX_12BIT;
352         ts->poll_period       = msecs_to_jiffies(pdata->poll_period ? : 1);
353         ts->get_pendown_state = pdata->get_pendown_state;
354         ts->clear_penirq      = pdata->clear_penirq;
355         ts->fuzzx             = pdata->fuzzx;
356         ts->fuzzy             = pdata->fuzzy;
357         ts->fuzzz             = pdata->fuzzz;
358 
359         if (pdata->x_plate_ohms == 0) {
360                 dev_err(&client->dev, "x_plate_ohms is not set up in platform data");
361                 return -EINVAL;
362         }
363 
364         return 0;
365 }
366 
367 static void tsc2007_call_exit_platform_hw(void *data)
368 {
369         struct device *dev = data;
370         const struct tsc2007_platform_data *pdata = dev_get_platdata(dev);
371 
372         pdata->exit_platform_hw();
373 }
374 
375 static int tsc2007_probe(struct i2c_client *client,
376                          const struct i2c_device_id *id)
377 {
378         const struct tsc2007_platform_data *pdata = dev_get_platdata(&client->dev);
379         struct tsc2007 *ts;
380         struct input_dev *input_dev;
381         int err;
382 
383         if (!i2c_check_functionality(client->adapter,
384                                      I2C_FUNC_SMBUS_READ_WORD_DATA))
385                 return -EIO;
386 
387         ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL);
388         if (!ts)
389                 return -ENOMEM;
390 
391         if (pdata)
392                 err = tsc2007_probe_pdev(client, ts, pdata, id);
393         else
394                 err = tsc2007_probe_dt(client, ts);
395         if (err)
396                 return err;
397 
398         input_dev = devm_input_allocate_device(&client->dev);
399         if (!input_dev)
400                 return -ENOMEM;
401 
402         i2c_set_clientdata(client, ts);
403 
404         ts->client = client;
405         ts->irq = client->irq;
406         ts->input = input_dev;
407         init_waitqueue_head(&ts->wait);
408 
409         snprintf(ts->phys, sizeof(ts->phys),
410                  "%s/input0", dev_name(&client->dev));
411 
412         input_dev->name = "TSC2007 Touchscreen";
413         input_dev->phys = ts->phys;
414         input_dev->id.bustype = BUS_I2C;
415 
416         input_dev->open = tsc2007_open;
417         input_dev->close = tsc2007_close;
418 
419         input_set_drvdata(input_dev, ts);
420 
421         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
422         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
423 
424         input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);
425         input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0);
426         input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
427                              ts->fuzzz, 0);
428 
429         if (pdata) {
430                 if (pdata->exit_platform_hw) {
431                         err = devm_add_action(&client->dev,
432                                               tsc2007_call_exit_platform_hw,
433                                               &client->dev);
434                         if (err) {
435                                 dev_err(&client->dev,
436                                         "Failed to register exit_platform_hw action, %d\n",
437                                         err);
438                                 return err;
439                         }
440                 }
441 
442                 if (pdata->init_platform_hw)
443                         pdata->init_platform_hw();
444         }
445 
446         err = devm_request_threaded_irq(&client->dev, ts->irq,
447                                         tsc2007_hard_irq, tsc2007_soft_irq,
448                                         IRQF_ONESHOT,
449                                         client->dev.driver->name, ts);
450         if (err) {
451                 dev_err(&client->dev, "Failed to request irq %d: %d\n",
452                         ts->irq, err);
453                 return err;
454         }
455 
456         tsc2007_stop(ts);
457 
458         err = input_register_device(input_dev);
459         if (err) {
460                 dev_err(&client->dev,
461                         "Failed to register input device: %d\n", err);
462                 return err;
463         }
464 
465         return 0;
466 }
467 
468 static const struct i2c_device_id tsc2007_idtable[] = {
469         { "tsc2007", 0 },
470         { }
471 };
472 
473 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
474 
475 #ifdef CONFIG_OF
476 static const struct of_device_id tsc2007_of_match[] = {
477         { .compatible = "ti,tsc2007" },
478         { /* sentinel */ }
479 };
480 MODULE_DEVICE_TABLE(of, tsc2007_of_match);
481 #endif
482 
483 static struct i2c_driver tsc2007_driver = {
484         .driver = {
485                 .owner  = THIS_MODULE,
486                 .name   = "tsc2007",
487                 .of_match_table = of_match_ptr(tsc2007_of_match),
488         },
489         .id_table       = tsc2007_idtable,
490         .probe          = tsc2007_probe,
491 };
492 
493 module_i2c_driver(tsc2007_driver);
494 
495 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
496 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
497 MODULE_LICENSE("GPL");
498 

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