Root/drivers/mfd/ucb1x00-ts.c

1/*
2 * Touchscreen driver for UCB1x00-based touchscreens
3 *
4 * Copyright (C) 2001 Russell King, All Rights Reserved.
5 * Copyright (C) 2005 Pavel Machek
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * 21-Jan-2002 <jco@ict.es> :
12 *
13 * Added support for synchronous A/D mode. This mode is useful to
14 * avoid noise induced in the touchpanel by the LCD, provided that
15 * the UCB1x00 has a valid LCD sync signal routed to its ADCSYNC pin.
16 * It is important to note that the signal connected to the ADCSYNC
17 * pin should provide pulses even when the LCD is blanked, otherwise
18 * a pen touch needed to unblank the LCD will never be read.
19 */
20#include <linux/module.h>
21#include <linux/moduleparam.h>
22#include <linux/init.h>
23#include <linux/interrupt.h>
24#include <linux/sched.h>
25#include <linux/spinlock.h>
26#include <linux/completion.h>
27#include <linux/delay.h>
28#include <linux/string.h>
29#include <linux/input.h>
30#include <linux/device.h>
31#include <linux/freezer.h>
32#include <linux/slab.h>
33#include <linux/kthread.h>
34#include <linux/mfd/ucb1x00.h>
35
36#include <mach/collie.h>
37#include <asm/mach-types.h>
38
39
40
41struct ucb1x00_ts {
42    struct input_dev *idev;
43    struct ucb1x00 *ucb;
44
45    spinlock_t irq_lock;
46    unsigned irq_disabled;
47    wait_queue_head_t irq_wait;
48    struct task_struct *rtask;
49    u16 x_res;
50    u16 y_res;
51
52    unsigned int adcsync:1;
53};
54
55static int adcsync;
56
57static inline void ucb1x00_ts_evt_add(struct ucb1x00_ts *ts, u16 pressure, u16 x, u16 y)
58{
59    struct input_dev *idev = ts->idev;
60
61    input_report_abs(idev, ABS_X, x);
62    input_report_abs(idev, ABS_Y, y);
63    input_report_abs(idev, ABS_PRESSURE, pressure);
64    input_report_key(idev, BTN_TOUCH, 1);
65    input_sync(idev);
66}
67
68static inline void ucb1x00_ts_event_release(struct ucb1x00_ts *ts)
69{
70    struct input_dev *idev = ts->idev;
71
72    input_report_abs(idev, ABS_PRESSURE, 0);
73    input_report_key(idev, BTN_TOUCH, 0);
74    input_sync(idev);
75}
76
77/*
78 * Switch to interrupt mode.
79 */
80static inline void ucb1x00_ts_mode_int(struct ucb1x00_ts *ts)
81{
82    ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
83            UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
84            UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
85            UCB_TS_CR_MODE_INT);
86}
87
88/*
89 * Switch to pressure mode, and read pressure. We don't need to wait
90 * here, since both plates are being driven.
91 */
92static inline unsigned int ucb1x00_ts_read_pressure(struct ucb1x00_ts *ts)
93{
94    if (machine_is_collie()) {
95        ucb1x00_io_write(ts->ucb, COLLIE_TC35143_GPIO_TBL_CHK, 0);
96        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
97                  UCB_TS_CR_TSPX_POW | UCB_TS_CR_TSMX_POW |
98                  UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
99
100        udelay(55);
101
102        return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_AD2, ts->adcsync);
103    } else {
104        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
105                  UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
106                  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
107                  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
108
109        return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
110    }
111}
112
113/*
114 * Switch to X position mode and measure Y plate. We switch the plate
115 * configuration in pressure mode, then switch to position mode. This
116 * gives a faster response time. Even so, we need to wait about 55us
117 * for things to stabilise.
118 */
119static inline unsigned int ucb1x00_ts_read_xpos(struct ucb1x00_ts *ts)
120{
121    if (machine_is_collie())
122        ucb1x00_io_write(ts->ucb, 0, COLLIE_TC35143_GPIO_TBL_CHK);
123    else {
124        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
125                  UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
126                  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
127        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
128                  UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
129                  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
130    }
131    ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
132            UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
133            UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
134
135    udelay(55);
136
137    return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
138}
139
140/*
141 * Switch to Y position mode and measure X plate. We switch the plate
142 * configuration in pressure mode, then switch to position mode. This
143 * gives a faster response time. Even so, we need to wait about 55us
144 * for things to stabilise.
145 */
146static inline unsigned int ucb1x00_ts_read_ypos(struct ucb1x00_ts *ts)
147{
148    if (machine_is_collie())
149        ucb1x00_io_write(ts->ucb, 0, COLLIE_TC35143_GPIO_TBL_CHK);
150    else {
151        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
152                  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
153                  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
154        ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
155                  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
156                  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
157    }
158
159    ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
160            UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
161            UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
162
163    udelay(55);
164
165    return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPX, ts->adcsync);
166}
167
168/*
169 * Switch to X plate resistance mode. Set MX to ground, PX to
170 * supply. Measure current.
171 */
172static inline unsigned int ucb1x00_ts_read_xres(struct ucb1x00_ts *ts)
173{
174    ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
175            UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
176            UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
177    return ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
178}
179
180/*
181 * Switch to Y plate resistance mode. Set MY to ground, PY to
182 * supply. Measure current.
183 */
184static inline unsigned int ucb1x00_ts_read_yres(struct ucb1x00_ts *ts)
185{
186    ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
187            UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
188            UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
189    return ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
190}
191
192static inline int ucb1x00_ts_pen_down(struct ucb1x00_ts *ts)
193{
194    unsigned int val = ucb1x00_reg_read(ts->ucb, UCB_TS_CR);
195
196    if (machine_is_collie())
197        return (!(val & (UCB_TS_CR_TSPX_LOW)));
198    else
199        return (val & (UCB_TS_CR_TSPX_LOW | UCB_TS_CR_TSMX_LOW));
200}
201
202/*
203 * This is a RT kernel thread that handles the ADC accesses
204 * (mainly so we can use semaphores in the UCB1200 core code
205 * to serialise accesses to the ADC).
206 */
207static int ucb1x00_thread(void *_ts)
208{
209    struct ucb1x00_ts *ts = _ts;
210    DECLARE_WAITQUEUE(wait, current);
211    bool frozen, ignore = false;
212    int valid = 0;
213
214    set_freezable();
215    add_wait_queue(&ts->irq_wait, &wait);
216    while (!kthread_freezable_should_stop(&frozen)) {
217        unsigned int x, y, p;
218        signed long timeout;
219
220        if (frozen)
221            ignore = true;
222
223        ucb1x00_adc_enable(ts->ucb);
224
225        x = ucb1x00_ts_read_xpos(ts);
226        y = ucb1x00_ts_read_ypos(ts);
227        p = ucb1x00_ts_read_pressure(ts);
228
229        /*
230         * Switch back to interrupt mode.
231         */
232        ucb1x00_ts_mode_int(ts);
233        ucb1x00_adc_disable(ts->ucb);
234
235        msleep(10);
236
237        ucb1x00_enable(ts->ucb);
238
239
240        if (ucb1x00_ts_pen_down(ts)) {
241            set_current_state(TASK_INTERRUPTIBLE);
242
243            spin_lock_irq(&ts->irq_lock);
244            if (ts->irq_disabled) {
245                ts->irq_disabled = 0;
246                enable_irq(ts->ucb->irq_base + UCB_IRQ_TSPX);
247            }
248            spin_unlock_irq(&ts->irq_lock);
249            ucb1x00_disable(ts->ucb);
250
251            /*
252             * If we spat out a valid sample set last time,
253             * spit out a "pen off" sample here.
254             */
255            if (valid) {
256                ucb1x00_ts_event_release(ts);
257                valid = 0;
258            }
259
260            timeout = MAX_SCHEDULE_TIMEOUT;
261        } else {
262            ucb1x00_disable(ts->ucb);
263
264            /*
265             * Filtering is policy. Policy belongs in user
266             * space. We therefore leave it to user space
267             * to do any filtering they please.
268             */
269            if (!ignore) {
270                ucb1x00_ts_evt_add(ts, p, x, y);
271                valid = 1;
272            }
273
274            set_current_state(TASK_INTERRUPTIBLE);
275            timeout = HZ / 100;
276        }
277
278        schedule_timeout(timeout);
279    }
280
281    remove_wait_queue(&ts->irq_wait, &wait);
282
283    ts->rtask = NULL;
284    return 0;
285}
286
287/*
288 * We only detect touch screen _touches_ with this interrupt
289 * handler, and even then we just schedule our task.
290 */
291static irqreturn_t ucb1x00_ts_irq(int irq, void *id)
292{
293    struct ucb1x00_ts *ts = id;
294
295    spin_lock(&ts->irq_lock);
296    ts->irq_disabled = 1;
297    disable_irq_nosync(ts->ucb->irq_base + UCB_IRQ_TSPX);
298    spin_unlock(&ts->irq_lock);
299    wake_up(&ts->irq_wait);
300
301    return IRQ_HANDLED;
302}
303
304static int ucb1x00_ts_open(struct input_dev *idev)
305{
306    struct ucb1x00_ts *ts = input_get_drvdata(idev);
307    unsigned long flags = 0;
308    int ret = 0;
309
310    BUG_ON(ts->rtask);
311
312    if (machine_is_collie())
313        flags = IRQF_TRIGGER_RISING;
314    else
315        flags = IRQF_TRIGGER_FALLING;
316
317    ts->irq_disabled = 0;
318
319    init_waitqueue_head(&ts->irq_wait);
320    ret = request_irq(ts->ucb->irq_base + UCB_IRQ_TSPX, ucb1x00_ts_irq,
321              flags, "ucb1x00-ts", ts);
322    if (ret < 0)
323        goto out;
324
325    /*
326     * If we do this at all, we should allow the user to
327     * measure and read the X and Y resistance at any time.
328     */
329    ucb1x00_adc_enable(ts->ucb);
330    ts->x_res = ucb1x00_ts_read_xres(ts);
331    ts->y_res = ucb1x00_ts_read_yres(ts);
332    ucb1x00_adc_disable(ts->ucb);
333
334    ts->rtask = kthread_run(ucb1x00_thread, ts, "ktsd");
335    if (!IS_ERR(ts->rtask)) {
336        ret = 0;
337    } else {
338        free_irq(ts->ucb->irq_base + UCB_IRQ_TSPX, ts);
339        ts->rtask = NULL;
340        ret = -EFAULT;
341    }
342
343 out:
344    return ret;
345}
346
347/*
348 * Release touchscreen resources. Disable IRQs.
349 */
350static void ucb1x00_ts_close(struct input_dev *idev)
351{
352    struct ucb1x00_ts *ts = input_get_drvdata(idev);
353
354    if (ts->rtask)
355        kthread_stop(ts->rtask);
356
357    ucb1x00_enable(ts->ucb);
358    free_irq(ts->ucb->irq_base + UCB_IRQ_TSPX, ts);
359    ucb1x00_reg_write(ts->ucb, UCB_TS_CR, 0);
360    ucb1x00_disable(ts->ucb);
361}
362
363
364/*
365 * Initialisation.
366 */
367static int ucb1x00_ts_add(struct ucb1x00_dev *dev)
368{
369    struct ucb1x00_ts *ts;
370    struct input_dev *idev;
371    int err;
372
373    ts = kzalloc(sizeof(struct ucb1x00_ts), GFP_KERNEL);
374    idev = input_allocate_device();
375    if (!ts || !idev) {
376        err = -ENOMEM;
377        goto fail;
378    }
379
380    ts->ucb = dev->ucb;
381    ts->idev = idev;
382    ts->adcsync = adcsync ? UCB_SYNC : UCB_NOSYNC;
383    spin_lock_init(&ts->irq_lock);
384
385    idev->name = "Touchscreen panel";
386    idev->id.product = ts->ucb->id;
387    idev->open = ucb1x00_ts_open;
388    idev->close = ucb1x00_ts_close;
389    idev->dev.parent = &ts->ucb->dev;
390
391    idev->evbit[0] = BIT_MASK(EV_ABS) | BIT_MASK(EV_KEY);
392    idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
393
394    input_set_drvdata(idev, ts);
395
396    ucb1x00_adc_enable(ts->ucb);
397    ts->x_res = ucb1x00_ts_read_xres(ts);
398    ts->y_res = ucb1x00_ts_read_yres(ts);
399    ucb1x00_adc_disable(ts->ucb);
400
401    input_set_abs_params(idev, ABS_X, 0, ts->x_res, 0, 0);
402    input_set_abs_params(idev, ABS_Y, 0, ts->y_res, 0, 0);
403    input_set_abs_params(idev, ABS_PRESSURE, 0, 0, 0, 0);
404
405    err = input_register_device(idev);
406    if (err)
407        goto fail;
408
409    dev->priv = ts;
410
411    return 0;
412
413 fail:
414    input_free_device(idev);
415    kfree(ts);
416    return err;
417}
418
419static void ucb1x00_ts_remove(struct ucb1x00_dev *dev)
420{
421    struct ucb1x00_ts *ts = dev->priv;
422
423    input_unregister_device(ts->idev);
424    kfree(ts);
425}
426
427static struct ucb1x00_driver ucb1x00_ts_driver = {
428    .add = ucb1x00_ts_add,
429    .remove = ucb1x00_ts_remove,
430};
431
432static int __init ucb1x00_ts_init(void)
433{
434    return ucb1x00_register_driver(&ucb1x00_ts_driver);
435}
436
437static void __exit ucb1x00_ts_exit(void)
438{
439    ucb1x00_unregister_driver(&ucb1x00_ts_driver);
440}
441
442module_param(adcsync, int, 0444);
443module_init(ucb1x00_ts_init);
444module_exit(ucb1x00_ts_exit);
445
446MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
447MODULE_DESCRIPTION("UCB1x00 touchscreen driver");
448MODULE_LICENSE("GPL");
449

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