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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 
 30 #define TS_POLL_DELAY                   1 /* ms delay between samples */
 31 #define TS_POLL_PERIOD                  1 /* ms delay between samples */
 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         struct delayed_work     work;
 73 
 74         struct i2c_client       *client;
 75 
 76         u16                     model;
 77         u16                     x_plate_ohms;
 78 
 79         bool                    pendown;
 80         int                     irq;
 81 
 82         int                     (*get_pendown_state)(void);
 83         void                    (*clear_penirq)(void);
 84 };
 85 
 86 static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
 87 {
 88         s32 data;
 89         u16 val;
 90 
 91         data = i2c_smbus_read_word_data(tsc->client, cmd);
 92         if (data < 0) {
 93                 dev_err(&tsc->client->dev, "i2c io error: %d\n", data);
 94                 return data;
 95         }
 96 
 97         /* The protocol and raw data format from i2c interface:
 98          * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P
 99          * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit].
100          */
101         val = swab16(data) >> 4;
102 
103         dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val);
104 
105         return val;
106 }
107 
108 static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
109 {
110         /* y- still on; turn on only y+ (and ADC) */
111         tc->y = tsc2007_xfer(tsc, READ_Y);
112 
113         /* turn y- off, x+ on, then leave in lowpower */
114         tc->x = tsc2007_xfer(tsc, READ_X);
115 
116         /* turn y+ off, x- on; we'll use formula #1 */
117         tc->z1 = tsc2007_xfer(tsc, READ_Z1);
118         tc->z2 = tsc2007_xfer(tsc, READ_Z2);
119 
120         /* Prepare for next touch reading - power down ADC, enable PENIRQ */
121         tsc2007_xfer(tsc, PWRDOWN);
122 }
123 
124 static u32 tsc2007_calculate_pressure(struct tsc2007 *tsc, struct ts_event *tc)
125 {
126         u32 rt = 0;
127 
128         /* range filtering */
129         if (tc->x == MAX_12BIT)
130                 tc->x = 0;
131 
132         if (likely(tc->x && tc->z1)) {
133                 /* compute touch pressure resistance using equation #1 */
134                 rt = tc->z2 - tc->z1;
135                 rt *= tc->x;
136                 rt *= tsc->x_plate_ohms;
137                 rt /= tc->z1;
138                 rt = (rt + 2047) >> 12;
139         }
140 
141         return rt;
142 }
143 
144 static void tsc2007_send_up_event(struct tsc2007 *tsc)
145 {
146         struct input_dev *input = tsc->input;
147 
148         dev_dbg(&tsc->client->dev, "UP\n");
149 
150         input_report_key(input, BTN_TOUCH, 0);
151         input_report_abs(input, ABS_PRESSURE, 0);
152         input_sync(input);
153 }
154 
155 static void tsc2007_work(struct work_struct *work)
156 {
157         struct tsc2007 *ts =
158                 container_of(to_delayed_work(work), struct tsc2007, work);
159         struct ts_event tc;
160         u32 rt;
161 
162         /*
163          * NOTE: We can't rely on the pressure to determine the pen down
164          * state, even though this controller has a pressure sensor.
165          * The pressure value can fluctuate for quite a while after
166          * lifting the pen and in some cases may not even settle at the
167          * expected value.
168          *
169          * The only safe way to check for the pen up condition is in the
170          * work function by reading the pen signal state (it's a GPIO
171          * and IRQ). Unfortunately such callback is not always available,
172          * in that case we have rely on the pressure anyway.
173          */
174         if (ts->get_pendown_state) {
175                 if (unlikely(!ts->get_pendown_state())) {
176                         tsc2007_send_up_event(ts);
177                         ts->pendown = false;
178                         goto out;
179                 }
180 
181                 dev_dbg(&ts->client->dev, "pen is still down\n");
182         }
183 
184         tsc2007_read_values(ts, &tc);
185 
186         rt = tsc2007_calculate_pressure(ts, &tc);
187         if (rt > MAX_12BIT) {
188                 /*
189                  * Sample found inconsistent by debouncing or pressure is
190                  * beyond the maximum. Don't report it to user space,
191                  * repeat at least once more the measurement.
192                  */
193                 dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
194                 goto out;
195 
196         }
197 
198         if (rt) {
199                 struct input_dev *input = ts->input;
200 
201                 if (!ts->pendown) {
202                         dev_dbg(&ts->client->dev, "DOWN\n");
203 
204                         input_report_key(input, BTN_TOUCH, 1);
205                         ts->pendown = true;
206                 }
207 
208                 input_report_abs(input, ABS_X, tc.x);
209                 input_report_abs(input, ABS_Y, tc.y);
210                 input_report_abs(input, ABS_PRESSURE, rt);
211 
212                 input_sync(input);
213 
214                 dev_dbg(&ts->client->dev, "point(%4d,%4d), pressure (%4u)\n",
215                         tc.x, tc.y, rt);
216 
217         } else if (!ts->get_pendown_state && ts->pendown) {
218                 /*
219                  * We don't have callback to check pendown state, so we
220                  * have to assume that since pressure reported is 0 the
221                  * pen was lifted up.
222                  */
223                 tsc2007_send_up_event(ts);
224                 ts->pendown = false;
225         }
226 
227  out:
228         if (ts->pendown)
229                 schedule_delayed_work(&ts->work,
230                                       msecs_to_jiffies(TS_POLL_PERIOD));
231         else
232                 enable_irq(ts->irq);
233 }
234 
235 static irqreturn_t tsc2007_irq(int irq, void *handle)
236 {
237         struct tsc2007 *ts = handle;
238 
239         if (!ts->get_pendown_state || likely(ts->get_pendown_state())) {
240                 disable_irq_nosync(ts->irq);
241                 schedule_delayed_work(&ts->work,
242                                       msecs_to_jiffies(TS_POLL_DELAY));
243         }
244 
245         if (ts->clear_penirq)
246                 ts->clear_penirq();
247 
248         return IRQ_HANDLED;
249 }
250 
251 static void tsc2007_free_irq(struct tsc2007 *ts)
252 {
253         free_irq(ts->irq, ts);
254         if (cancel_delayed_work_sync(&ts->work)) {
255                 /*
256                  * Work was pending, therefore we need to enable
257                  * IRQ here to balance the disable_irq() done in the
258                  * interrupt handler.
259                  */
260                 enable_irq(ts->irq);
261         }
262 }
263 
264 static int __devinit tsc2007_probe(struct i2c_client *client,
265                                    const struct i2c_device_id *id)
266 {
267         struct tsc2007 *ts;
268         struct tsc2007_platform_data *pdata = pdata = client->dev.platform_data;
269         struct input_dev *input_dev;
270         int err;
271 
272         if (!pdata) {
273                 dev_err(&client->dev, "platform data is required!\n");
274                 return -EINVAL;
275         }
276 
277         if (!i2c_check_functionality(client->adapter,
278                                      I2C_FUNC_SMBUS_READ_WORD_DATA))
279                 return -EIO;
280 
281         ts = kzalloc(sizeof(struct tsc2007), GFP_KERNEL);
282         input_dev = input_allocate_device();
283         if (!ts || !input_dev) {
284                 err = -ENOMEM;
285                 goto err_free_mem;
286         }
287 
288         ts->client = client;
289         ts->irq = client->irq;
290         ts->input = input_dev;
291         INIT_DELAYED_WORK(&ts->work, tsc2007_work);
292 
293         ts->model             = pdata->model;
294         ts->x_plate_ohms      = pdata->x_plate_ohms;
295         ts->get_pendown_state = pdata->get_pendown_state;
296         ts->clear_penirq      = pdata->clear_penirq;
297 
298         snprintf(ts->phys, sizeof(ts->phys),
299                  "%s/input0", dev_name(&client->dev));
300 
301         input_dev->name = "TSC2007 Touchscreen";
302         input_dev->phys = ts->phys;
303         input_dev->id.bustype = BUS_I2C;
304 
305         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
306         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
307 
308         input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
309         input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
310         input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
311 
312         if (pdata->init_platform_hw)
313                 pdata->init_platform_hw();
314 
315         err = request_irq(ts->irq, tsc2007_irq, 0,
316                         client->dev.driver->name, ts);
317         if (err < 0) {
318                 dev_err(&client->dev, "irq %d busy?\n", ts->irq);
319                 goto err_free_mem;
320         }
321 
322         /* Prepare for touch readings - power down ADC and enable PENIRQ */
323         err = tsc2007_xfer(ts, PWRDOWN);
324         if (err < 0)
325                 goto err_free_irq;
326 
327         err = input_register_device(input_dev);
328         if (err)
329                 goto err_free_irq;
330 
331         i2c_set_clientdata(client, ts);
332 
333         return 0;
334 
335  err_free_irq:
336         tsc2007_free_irq(ts);
337         if (pdata->exit_platform_hw)
338                 pdata->exit_platform_hw();
339  err_free_mem:
340         input_free_device(input_dev);
341         kfree(ts);
342         return err;
343 }
344 
345 static int __devexit tsc2007_remove(struct i2c_client *client)
346 {
347         struct tsc2007  *ts = i2c_get_clientdata(client);
348         struct tsc2007_platform_data *pdata = client->dev.platform_data;
349 
350         tsc2007_free_irq(ts);
351 
352         if (pdata->exit_platform_hw)
353                 pdata->exit_platform_hw();
354 
355         input_unregister_device(ts->input);
356         kfree(ts);
357 
358         return 0;
359 }
360 
361 static struct i2c_device_id tsc2007_idtable[] = {
362         { "tsc2007", 0 },
363         { }
364 };
365 
366 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
367 
368 static struct i2c_driver tsc2007_driver = {
369         .driver = {
370                 .owner  = THIS_MODULE,
371                 .name   = "tsc2007"
372         },
373         .id_table       = tsc2007_idtable,
374         .probe          = tsc2007_probe,
375         .remove         = __devexit_p(tsc2007_remove),
376 };
377 
378 static int __init tsc2007_init(void)
379 {
380         return i2c_add_driver(&tsc2007_driver);
381 }
382 
383 static void __exit tsc2007_exit(void)
384 {
385         i2c_del_driver(&tsc2007_driver);
386 }
387 
388 module_init(tsc2007_init);
389 module_exit(tsc2007_exit);
390 
391 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
392 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
393 MODULE_LICENSE("GPL");
394 

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