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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;
 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,
218                                    msecs_to_jiffies(ts->poll_period));
219         }
220 
221         dev_dbg(&ts->client->dev, "UP\n");
222 
223         input_report_key(input, BTN_TOUCH, 0);
224         input_report_abs(input, ABS_PRESSURE, 0);
225         input_sync(input);
226 
227         if (ts->clear_penirq)
228                 ts->clear_penirq();
229 
230         return IRQ_HANDLED;
231 }
232 
233 static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
234 {
235         struct tsc2007 *ts = handle;
236 
237         if (tsc2007_is_pen_down(ts))
238                 return IRQ_WAKE_THREAD;
239 
240         if (ts->clear_penirq)
241                 ts->clear_penirq();
242 
243         return IRQ_HANDLED;
244 }
245 
246 static void tsc2007_stop(struct tsc2007 *ts)
247 {
248         ts->stopped = true;
249         mb();
250         wake_up(&ts->wait);
251 
252         disable_irq(ts->irq);
253 }
254 
255 static int tsc2007_open(struct input_dev *input_dev)
256 {
257         struct tsc2007 *ts = input_get_drvdata(input_dev);
258         int err;
259 
260         ts->stopped = false;
261         mb();
262 
263         enable_irq(ts->irq);
264 
265         /* Prepare for touch readings - power down ADC and enable PENIRQ */
266         err = tsc2007_xfer(ts, PWRDOWN);
267         if (err < 0) {
268                 tsc2007_stop(ts);
269                 return err;
270         }
271 
272         return 0;
273 }
274 
275 static void tsc2007_close(struct input_dev *input_dev)
276 {
277         struct tsc2007 *ts = input_get_drvdata(input_dev);
278 
279         tsc2007_stop(ts);
280 }
281 
282 #ifdef CONFIG_OF
283 static int tsc2007_get_pendown_state_gpio(struct device *dev)
284 {
285         struct i2c_client *client = to_i2c_client(dev);
286         struct tsc2007 *ts = i2c_get_clientdata(client);
287 
288         return !gpio_get_value(ts->gpio);
289 }
290 
291 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
292 {
293         struct device_node *np = client->dev.of_node;
294         u32 val32;
295         u64 val64;
296 
297         if (!np) {
298                 dev_err(&client->dev, "missing device tree data\n");
299                 return -EINVAL;
300         }
301 
302         if (!of_property_read_u32(np, "ti,max-rt", &val32))
303                 ts->max_rt = val32;
304         else
305                 ts->max_rt = MAX_12BIT;
306 
307         if (!of_property_read_u32(np, "ti,fuzzx", &val32))
308                 ts->fuzzx = val32;
309 
310         if (!of_property_read_u32(np, "ti,fuzzy", &val32))
311                 ts->fuzzy = val32;
312 
313         if (!of_property_read_u32(np, "ti,fuzzz", &val32))
314                 ts->fuzzz = val32;
315 
316         if (!of_property_read_u64(np, "ti,poll-period", &val64))
317                 ts->poll_period = val64;
318         else
319                 ts->poll_period = 1;
320 
321         if (!of_property_read_u32(np, "ti,x-plate-ohms", &val32)) {
322                 ts->x_plate_ohms = val32;
323         } else {
324                 dev_err(&client->dev, "missing ti,x-plate-ohms devicetree property.");
325                 return -EINVAL;
326         }
327 
328         ts->gpio = of_get_gpio(np, 0);
329         if (gpio_is_valid(ts->gpio))
330                 ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
331         else
332                 dev_warn(&client->dev,
333                          "GPIO not specified in DT (of_get_gpio returned %d)\n",
334                          ts->gpio);
335 
336         return 0;
337 }
338 #else
339 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
340 {
341         dev_err(&client->dev, "platform data is required!\n");
342         return -EINVAL;
343 }
344 #endif
345 
346 static int tsc2007_probe_pdev(struct i2c_client *client, struct tsc2007 *ts,
347                               const struct tsc2007_platform_data *pdata,
348                               const struct i2c_device_id *id)
349 {
350         ts->model             = pdata->model;
351         ts->x_plate_ohms      = pdata->x_plate_ohms;
352         ts->max_rt            = pdata->max_rt ? : MAX_12BIT;
353         ts->poll_period       = pdata->poll_period ? : 1;
354         ts->get_pendown_state = pdata->get_pendown_state;
355         ts->clear_penirq      = pdata->clear_penirq;
356         ts->fuzzx             = pdata->fuzzx;
357         ts->fuzzy             = pdata->fuzzy;
358         ts->fuzzz             = pdata->fuzzz;
359 
360         if (pdata->x_plate_ohms == 0) {
361                 dev_err(&client->dev, "x_plate_ohms is not set up in platform data");
362                 return -EINVAL;
363         }
364 
365         return 0;
366 }
367 
368 static void tsc2007_call_exit_platform_hw(void *data)
369 {
370         struct device *dev = data;
371         const struct tsc2007_platform_data *pdata = dev_get_platdata(dev);
372 
373         pdata->exit_platform_hw();
374 }
375 
376 static int tsc2007_probe(struct i2c_client *client,
377                          const struct i2c_device_id *id)
378 {
379         const struct tsc2007_platform_data *pdata = dev_get_platdata(&client->dev);
380         struct tsc2007 *ts;
381         struct input_dev *input_dev;
382         int err;
383 
384         if (!i2c_check_functionality(client->adapter,
385                                      I2C_FUNC_SMBUS_READ_WORD_DATA))
386                 return -EIO;
387 
388         ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL);
389         if (!ts)
390                 return -ENOMEM;
391 
392         if (pdata)
393                 err = tsc2007_probe_pdev(client, ts, pdata, id);
394         else
395                 err = tsc2007_probe_dt(client, ts);
396         if (err)
397                 return err;
398 
399         input_dev = devm_input_allocate_device(&client->dev);
400         if (!input_dev)
401                 return -ENOMEM;
402 
403         i2c_set_clientdata(client, ts);
404 
405         ts->client = client;
406         ts->irq = client->irq;
407         ts->input = input_dev;
408         init_waitqueue_head(&ts->wait);
409 
410         snprintf(ts->phys, sizeof(ts->phys),
411                  "%s/input0", dev_name(&client->dev));
412 
413         input_dev->name = "TSC2007 Touchscreen";
414         input_dev->phys = ts->phys;
415         input_dev->id.bustype = BUS_I2C;
416 
417         input_dev->open = tsc2007_open;
418         input_dev->close = tsc2007_close;
419 
420         input_set_drvdata(input_dev, ts);
421 
422         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
423         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
424 
425         input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);
426         input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0);
427         input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
428                              ts->fuzzz, 0);
429 
430         if (pdata) {
431                 if (pdata->exit_platform_hw) {
432                         err = devm_add_action(&client->dev,
433                                               tsc2007_call_exit_platform_hw,
434                                               &client->dev);
435                         if (err) {
436                                 dev_err(&client->dev,
437                                         "Failed to register exit_platform_hw action, %d\n",
438                                         err);
439                                 return err;
440                         }
441                 }
442 
443                 if (pdata->init_platform_hw)
444                         pdata->init_platform_hw();
445         }
446 
447         err = devm_request_threaded_irq(&client->dev, ts->irq,
448                                         tsc2007_hard_irq, tsc2007_soft_irq,
449                                         IRQF_ONESHOT,
450                                         client->dev.driver->name, ts);
451         if (err) {
452                 dev_err(&client->dev, "Failed to request irq %d: %d\n",
453                         ts->irq, err);
454                 return err;
455         }
456 
457         tsc2007_stop(ts);
458 
459         err = input_register_device(input_dev);
460         if (err) {
461                 dev_err(&client->dev,
462                         "Failed to register input device: %d\n", err);
463                 return err;
464         }
465 
466         return 0;
467 }
468 
469 static const struct i2c_device_id tsc2007_idtable[] = {
470         { "tsc2007", 0 },
471         { }
472 };
473 
474 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
475 
476 #ifdef CONFIG_OF
477 static const struct of_device_id tsc2007_of_match[] = {
478         { .compatible = "ti,tsc2007" },
479         { /* sentinel */ }
480 };
481 MODULE_DEVICE_TABLE(of, tsc2007_of_match);
482 #endif
483 
484 static struct i2c_driver tsc2007_driver = {
485         .driver = {
486                 .owner  = THIS_MODULE,
487                 .name   = "tsc2007",
488                 .of_match_table = of_match_ptr(tsc2007_of_match),
489         },
490         .id_table       = tsc2007_idtable,
491         .probe          = tsc2007_probe,
492 };
493 
494 module_i2c_driver(tsc2007_driver);
495 
496 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
497 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
498 MODULE_LICENSE("GPL");
499 

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