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ffa458c1 DB |
1 | /* |
2 | * ADS7846 based touchscreen and sensor driver | |
3 | * | |
4 | * Copyright (c) 2005 David Brownell | |
7de90a8c ID |
5 | * Copyright (c) 2006 Nokia Corporation |
6 | * Various changes: Imre Deak <imre.deak@nokia.com> | |
ffa458c1 DB |
7 | * |
8 | * Using code from: | |
9 | * - corgi_ts.c | |
10 | * Copyright (C) 2004-2005 Richard Purdie | |
11 | * - omap_ts.[hc], ads7846.h, ts_osk.c | |
12 | * Copyright (C) 2002 MontaVista Software | |
13 | * Copyright (C) 2004 Texas Instruments | |
14 | * Copyright (C) 2005 Dirk Behme | |
15 | * | |
16 | * This program is free software; you can redistribute it and/or modify | |
17 | * it under the terms of the GNU General Public License version 2 as | |
18 | * published by the Free Software Foundation. | |
19 | */ | |
20 | #include <linux/device.h> | |
21 | #include <linux/init.h> | |
22 | #include <linux/delay.h> | |
23 | #include <linux/input.h> | |
24 | #include <linux/interrupt.h> | |
25 | #include <linux/slab.h> | |
26 | #include <linux/spi/spi.h> | |
27 | #include <linux/spi/ads7846.h> | |
3ac8bf07 | 28 | #include <asm/irq.h> |
ffa458c1 DB |
29 | |
30 | #ifdef CONFIG_ARM | |
31 | #include <asm/mach-types.h> | |
32 | #ifdef CONFIG_ARCH_OMAP | |
33 | #include <asm/arch/gpio.h> | |
34 | #endif | |
ffa458c1 DB |
35 | #endif |
36 | ||
37 | ||
38 | /* | |
9084533e DB |
39 | * This code has been heavily tested on a Nokia 770, and lightly |
40 | * tested on other ads7846 devices (OSK/Mistral, Lubbock). | |
ffa458c1 DB |
41 | * Support for ads7843 and ads7845 has only been stubbed in. |
42 | * | |
7de90a8c ID |
43 | * IRQ handling needs a workaround because of a shortcoming in handling |
44 | * edge triggered IRQs on some platforms like the OMAP1/2. These | |
45 | * platforms don't handle the ARM lazy IRQ disabling properly, thus we | |
46 | * have to maintain our own SW IRQ disabled status. This should be | |
47 | * removed as soon as the affected platform's IRQ handling is fixed. | |
48 | * | |
ffa458c1 DB |
49 | * app note sbaa036 talks in more detail about accurate sampling... |
50 | * that ought to help in situations like LCDs inducing noise (which | |
51 | * can also be helped by using synch signals) and more generally. | |
7de90a8c ID |
52 | * This driver tries to utilize the measures described in the app |
53 | * note. The strength of filtering can be set in the board-* specific | |
54 | * files. | |
ffa458c1 DB |
55 | */ |
56 | ||
57 | #define TS_POLL_PERIOD msecs_to_jiffies(10) | |
58 | ||
d93f70b2 DB |
59 | /* this driver doesn't aim at the peak continuous sample rate */ |
60 | #define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */) | |
61 | ||
ffa458c1 DB |
62 | struct ts_event { |
63 | /* For portability, we can't read 12 bit values using SPI (which | |
64 | * would make the controller deliver them as native byteorder u16 | |
d93f70b2 | 65 | * with msbs zeroed). Instead, we read them as two 8-bit values, |
ffa458c1 DB |
66 | * which need byteswapping then range adjustment. |
67 | */ | |
68 | __be16 x; | |
69 | __be16 y; | |
70 | __be16 z1, z2; | |
d5b415c9 | 71 | int ignore; |
ffa458c1 DB |
72 | }; |
73 | ||
74 | struct ads7846 { | |
a90f7e98 | 75 | struct input_dev *input; |
ffa458c1 DB |
76 | char phys[32]; |
77 | ||
78 | struct spi_device *spi; | |
8dd51650 | 79 | struct attribute_group *attr_group; |
ffa458c1 DB |
80 | u16 model; |
81 | u16 vref_delay_usecs; | |
82 | u16 x_plate_ohms; | |
d5b415c9 | 83 | u16 pressure_max; |
ffa458c1 | 84 | |
53a0ef89 ID |
85 | u8 read_x, read_y, read_z1, read_z2, pwrdown; |
86 | u16 dummy; /* for the pwrdown read */ | |
ffa458c1 DB |
87 | struct ts_event tc; |
88 | ||
53a0ef89 | 89 | struct spi_transfer xfer[10]; |
0b7018aa | 90 | struct spi_message msg[5]; |
d5b415c9 | 91 | struct spi_message *last_msg; |
0b7018aa ID |
92 | int msg_idx; |
93 | int read_cnt; | |
d5b415c9 | 94 | int read_rep; |
0b7018aa ID |
95 | int last_read; |
96 | ||
97 | u16 debounce_max; | |
98 | u16 debounce_tol; | |
d5b415c9 | 99 | u16 debounce_rep; |
ffa458c1 DB |
100 | |
101 | spinlock_t lock; | |
102 | struct timer_list timer; /* P: lock */ | |
103 | unsigned pendown:1; /* P: lock */ | |
104 | unsigned pending:1; /* P: lock */ | |
105 | // FIXME remove "irq_disabled" | |
106 | unsigned irq_disabled:1; /* P: lock */ | |
7de90a8c | 107 | unsigned disabled:1; |
c9e617a5 ID |
108 | |
109 | int (*get_pendown_state)(void); | |
ffa458c1 DB |
110 | }; |
111 | ||
112 | /* leave chip selected when we're done, for quicker re-select? */ | |
113 | #if 0 | |
114 | #define CS_CHANGE(xfer) ((xfer).cs_change = 1) | |
115 | #else | |
116 | #define CS_CHANGE(xfer) ((xfer).cs_change = 0) | |
117 | #endif | |
118 | ||
119 | /*--------------------------------------------------------------------------*/ | |
120 | ||
121 | /* The ADS7846 has touchscreen and other sensors. | |
122 | * Earlier ads784x chips are somewhat compatible. | |
123 | */ | |
124 | #define ADS_START (1 << 7) | |
125 | #define ADS_A2A1A0_d_y (1 << 4) /* differential */ | |
126 | #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */ | |
127 | #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */ | |
128 | #define ADS_A2A1A0_d_x (5 << 4) /* differential */ | |
129 | #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */ | |
130 | #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */ | |
131 | #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */ | |
132 | #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */ | |
133 | #define ADS_8_BIT (1 << 3) | |
134 | #define ADS_12_BIT (0 << 3) | |
135 | #define ADS_SER (1 << 2) /* non-differential */ | |
136 | #define ADS_DFR (0 << 2) /* differential */ | |
137 | #define ADS_PD10_PDOWN (0 << 0) /* lowpower mode + penirq */ | |
138 | #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */ | |
139 | #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */ | |
140 | #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */ | |
141 | ||
142 | #define MAX_12BIT ((1<<12)-1) | |
143 | ||
144 | /* leave ADC powered up (disables penirq) between differential samples */ | |
145 | #define READ_12BIT_DFR(x) (ADS_START | ADS_A2A1A0_d_ ## x \ | |
146 | | ADS_12_BIT | ADS_DFR) | |
147 | ||
d93f70b2 DB |
148 | #define READ_Y (READ_12BIT_DFR(y) | ADS_PD10_ADC_ON) |
149 | #define READ_Z1 (READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON) | |
150 | #define READ_Z2 (READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON) | |
53a0ef89 ID |
151 | |
152 | #define READ_X (READ_12BIT_DFR(x) | ADS_PD10_ADC_ON) | |
153 | #define PWRDOWN (READ_12BIT_DFR(y) | ADS_PD10_PDOWN) /* LAST */ | |
ffa458c1 DB |
154 | |
155 | /* single-ended samples need to first power up reference voltage; | |
156 | * we leave both ADC and VREF powered | |
157 | */ | |
158 | #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \ | |
159 | | ADS_12_BIT | ADS_SER) | |
160 | ||
d93f70b2 DB |
161 | #define REF_ON (READ_12BIT_DFR(x) | ADS_PD10_ALL_ON) |
162 | #define REF_OFF (READ_12BIT_DFR(y) | ADS_PD10_PDOWN) | |
ffa458c1 DB |
163 | |
164 | /*--------------------------------------------------------------------------*/ | |
165 | ||
166 | /* | |
167 | * Non-touchscreen sensors only use single-ended conversions. | |
168 | */ | |
169 | ||
170 | struct ser_req { | |
d93f70b2 | 171 | u8 ref_on; |
ffa458c1 | 172 | u8 command; |
d93f70b2 | 173 | u8 ref_off; |
ffa458c1 DB |
174 | u16 scratch; |
175 | __be16 sample; | |
176 | struct spi_message msg; | |
177 | struct spi_transfer xfer[6]; | |
178 | }; | |
179 | ||
7de90a8c ID |
180 | static void ads7846_enable(struct ads7846 *ts); |
181 | static void ads7846_disable(struct ads7846 *ts); | |
182 | ||
c9e617a5 ID |
183 | static int device_suspended(struct device *dev) |
184 | { | |
185 | struct ads7846 *ts = dev_get_drvdata(dev); | |
186 | return dev->power.power_state.event != PM_EVENT_ON || ts->disabled; | |
187 | } | |
188 | ||
ffa458c1 DB |
189 | static int ads7846_read12_ser(struct device *dev, unsigned command) |
190 | { | |
191 | struct spi_device *spi = to_spi_device(dev); | |
192 | struct ads7846 *ts = dev_get_drvdata(dev); | |
e94b1766 | 193 | struct ser_req *req = kzalloc(sizeof *req, GFP_KERNEL); |
ffa458c1 DB |
194 | int status; |
195 | int sample; | |
a90f7e98 | 196 | int i; |
ffa458c1 DB |
197 | |
198 | if (!req) | |
199 | return -ENOMEM; | |
200 | ||
0b7018aa | 201 | spi_message_init(&req->msg); |
8275c642 | 202 | |
ffa458c1 | 203 | /* activate reference, so it has time to settle; */ |
d93f70b2 DB |
204 | req->ref_on = REF_ON; |
205 | req->xfer[0].tx_buf = &req->ref_on; | |
ffa458c1 DB |
206 | req->xfer[0].len = 1; |
207 | req->xfer[1].rx_buf = &req->scratch; | |
208 | req->xfer[1].len = 2; | |
209 | ||
210 | /* | |
211 | * for external VREF, 0 usec (and assume it's always on); | |
212 | * for 1uF, use 800 usec; | |
213 | * no cap, 100 usec. | |
214 | */ | |
215 | req->xfer[1].delay_usecs = ts->vref_delay_usecs; | |
216 | ||
217 | /* take sample */ | |
218 | req->command = (u8) command; | |
219 | req->xfer[2].tx_buf = &req->command; | |
220 | req->xfer[2].len = 1; | |
221 | req->xfer[3].rx_buf = &req->sample; | |
222 | req->xfer[3].len = 2; | |
223 | ||
224 | /* REVISIT: take a few more samples, and compare ... */ | |
225 | ||
226 | /* turn off reference */ | |
d93f70b2 DB |
227 | req->ref_off = REF_OFF; |
228 | req->xfer[4].tx_buf = &req->ref_off; | |
ffa458c1 DB |
229 | req->xfer[4].len = 1; |
230 | req->xfer[5].rx_buf = &req->scratch; | |
231 | req->xfer[5].len = 2; | |
232 | ||
233 | CS_CHANGE(req->xfer[5]); | |
234 | ||
235 | /* group all the transfers together, so we can't interfere with | |
236 | * reading touchscreen state; disable penirq while sampling | |
237 | */ | |
8275c642 VW |
238 | for (i = 0; i < 6; i++) |
239 | spi_message_add_tail(&req->xfer[i], &req->msg); | |
ffa458c1 | 240 | |
c9e617a5 | 241 | ts->irq_disabled = 1; |
ffa458c1 DB |
242 | disable_irq(spi->irq); |
243 | status = spi_sync(spi, &req->msg); | |
c9e617a5 | 244 | ts->irq_disabled = 0; |
ffa458c1 DB |
245 | enable_irq(spi->irq); |
246 | ||
247 | if (req->msg.status) | |
248 | status = req->msg.status; | |
9084533e DB |
249 | |
250 | /* on-wire is a must-ignore bit, a BE12 value, then padding */ | |
ffa458c1 | 251 | sample = be16_to_cpu(req->sample); |
9084533e DB |
252 | sample = sample >> 3; |
253 | sample &= 0x0fff; | |
ffa458c1 | 254 | |
9084533e | 255 | kfree(req); |
ffa458c1 DB |
256 | return status ? status : sample; |
257 | } | |
258 | ||
259 | #define SHOW(name) static ssize_t \ | |
260 | name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \ | |
261 | { \ | |
262 | ssize_t v = ads7846_read12_ser(dev, \ | |
263 | READ_12BIT_SER(name) | ADS_PD10_ALL_ON); \ | |
264 | if (v < 0) \ | |
265 | return v; \ | |
266 | return sprintf(buf, "%u\n", (unsigned) v); \ | |
267 | } \ | |
268 | static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL); | |
269 | ||
270 | SHOW(temp0) | |
271 | SHOW(temp1) | |
272 | SHOW(vaux) | |
273 | SHOW(vbatt) | |
274 | ||
438f2a74 ID |
275 | static int is_pen_down(struct device *dev) |
276 | { | |
277 | struct ads7846 *ts = dev_get_drvdata(dev); | |
278 | ||
279 | return ts->pendown; | |
280 | } | |
281 | ||
282 | static ssize_t ads7846_pen_down_show(struct device *dev, | |
283 | struct device_attribute *attr, char *buf) | |
284 | { | |
285 | return sprintf(buf, "%u\n", is_pen_down(dev)); | |
286 | } | |
287 | ||
288 | static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL); | |
289 | ||
7de90a8c ID |
290 | static ssize_t ads7846_disable_show(struct device *dev, |
291 | struct device_attribute *attr, char *buf) | |
292 | { | |
293 | struct ads7846 *ts = dev_get_drvdata(dev); | |
294 | ||
295 | return sprintf(buf, "%u\n", ts->disabled); | |
296 | } | |
297 | ||
298 | static ssize_t ads7846_disable_store(struct device *dev, | |
299 | struct device_attribute *attr, | |
300 | const char *buf, size_t count) | |
301 | { | |
302 | struct ads7846 *ts = dev_get_drvdata(dev); | |
303 | char *endp; | |
304 | int i; | |
305 | ||
306 | i = simple_strtoul(buf, &endp, 10); | |
307 | spin_lock_irq(&ts->lock); | |
308 | ||
309 | if (i) | |
310 | ads7846_disable(ts); | |
311 | else | |
312 | ads7846_enable(ts); | |
313 | ||
314 | spin_unlock_irq(&ts->lock); | |
315 | ||
316 | return count; | |
317 | } | |
318 | ||
319 | static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store); | |
320 | ||
8dd51650 DT |
321 | static struct attribute *ads7846_attributes[] = { |
322 | &dev_attr_temp0.attr, | |
323 | &dev_attr_temp1.attr, | |
324 | &dev_attr_vbatt.attr, | |
325 | &dev_attr_vaux.attr, | |
326 | &dev_attr_pen_down.attr, | |
327 | &dev_attr_disable.attr, | |
328 | NULL, | |
329 | }; | |
330 | ||
331 | static struct attribute_group ads7846_attr_group = { | |
332 | .attrs = ads7846_attributes, | |
333 | }; | |
334 | ||
335 | /* | |
336 | * ads7843/7845 don't have temperature sensors, and | |
337 | * use the other sensors a bit differently too | |
338 | */ | |
339 | ||
340 | static struct attribute *ads7843_attributes[] = { | |
341 | &dev_attr_vbatt.attr, | |
342 | &dev_attr_vaux.attr, | |
343 | &dev_attr_pen_down.attr, | |
344 | &dev_attr_disable.attr, | |
345 | NULL, | |
346 | }; | |
347 | ||
348 | static struct attribute_group ads7843_attr_group = { | |
349 | .attrs = ads7843_attributes, | |
350 | }; | |
351 | ||
352 | static struct attribute *ads7845_attributes[] = { | |
353 | &dev_attr_vaux.attr, | |
354 | &dev_attr_pen_down.attr, | |
355 | &dev_attr_disable.attr, | |
356 | NULL, | |
357 | }; | |
358 | ||
359 | static struct attribute_group ads7845_attr_group = { | |
360 | .attrs = ads7845_attributes, | |
361 | }; | |
362 | ||
ffa458c1 DB |
363 | /*--------------------------------------------------------------------------*/ |
364 | ||
365 | /* | |
366 | * PENIRQ only kicks the timer. The timer only reissues the SPI transfer, | |
367 | * to retrieve touchscreen status. | |
368 | * | |
369 | * The SPI transfer completion callback does the real work. It reports | |
370 | * touchscreen events and reactivates the timer (or IRQ) as appropriate. | |
371 | */ | |
372 | ||
373 | static void ads7846_rx(void *ads) | |
374 | { | |
a90f7e98 DT |
375 | struct ads7846 *ts = ads; |
376 | struct input_dev *input_dev = ts->input; | |
377 | unsigned Rt; | |
378 | unsigned sync = 0; | |
379 | u16 x, y, z1, z2; | |
380 | unsigned long flags; | |
ffa458c1 | 381 | |
9084533e DB |
382 | /* adjust: on-wire is a must-ignore bit, a BE12 value, then padding; |
383 | * built from two 8 bit values written msb-first. | |
ffa458c1 | 384 | */ |
9084533e DB |
385 | x = (be16_to_cpu(ts->tc.x) >> 3) & 0x0fff; |
386 | y = (be16_to_cpu(ts->tc.y) >> 3) & 0x0fff; | |
387 | z1 = (be16_to_cpu(ts->tc.z1) >> 3) & 0x0fff; | |
388 | z2 = (be16_to_cpu(ts->tc.z2) >> 3) & 0x0fff; | |
ffa458c1 DB |
389 | |
390 | /* range filtering */ | |
391 | if (x == MAX_12BIT) | |
392 | x = 0; | |
393 | ||
c9e617a5 | 394 | if (likely(x && z1 && !device_suspended(&ts->spi->dev))) { |
ffa458c1 DB |
395 | /* compute touch pressure resistance using equation #2 */ |
396 | Rt = z2; | |
397 | Rt -= z1; | |
398 | Rt *= x; | |
399 | Rt *= ts->x_plate_ohms; | |
400 | Rt /= z1; | |
401 | Rt = (Rt + 2047) >> 12; | |
402 | } else | |
403 | Rt = 0; | |
404 | ||
d5b415c9 ID |
405 | /* Sample found inconsistent by debouncing or pressure is beyond |
406 | * the maximum. Don't report it to user space, repeat at least | |
407 | * once more the measurement */ | |
408 | if (ts->tc.ignore || Rt > ts->pressure_max) { | |
409 | mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD); | |
410 | return; | |
411 | } | |
412 | ||
ffa458c1 DB |
413 | /* NOTE: "pendown" is inferred from pressure; we don't rely on |
414 | * being able to check nPENIRQ status, or "friendly" trigger modes | |
415 | * (both-edges is much better than just-falling or low-level). | |
416 | * | |
417 | * REVISIT: some boards may require reading nPENIRQ; it's | |
418 | * needed on 7843. and 7845 reads pressure differently... | |
419 | * | |
420 | * REVISIT: the touchscreen might not be connected; this code | |
421 | * won't notice that, even if nPENIRQ never fires ... | |
422 | */ | |
423 | if (!ts->pendown && Rt != 0) { | |
a90f7e98 | 424 | input_report_key(input_dev, BTN_TOUCH, 1); |
ffa458c1 DB |
425 | sync = 1; |
426 | } else if (ts->pendown && Rt == 0) { | |
a90f7e98 | 427 | input_report_key(input_dev, BTN_TOUCH, 0); |
ffa458c1 DB |
428 | sync = 1; |
429 | } | |
430 | ||
431 | if (Rt) { | |
a90f7e98 DT |
432 | input_report_abs(input_dev, ABS_X, x); |
433 | input_report_abs(input_dev, ABS_Y, y); | |
ffa458c1 DB |
434 | sync = 1; |
435 | } | |
ae82d5ab ID |
436 | |
437 | if (sync) { | |
438 | input_report_abs(input_dev, ABS_PRESSURE, Rt); | |
a90f7e98 | 439 | input_sync(input_dev); |
ae82d5ab | 440 | } |
ffa458c1 DB |
441 | |
442 | #ifdef VERBOSE | |
443 | if (Rt || ts->pendown) | |
444 | pr_debug("%s: %d/%d/%d%s\n", ts->spi->dev.bus_id, | |
445 | x, y, Rt, Rt ? "" : " UP"); | |
446 | #endif | |
447 | ||
ffa458c1 DB |
448 | spin_lock_irqsave(&ts->lock, flags); |
449 | ||
450 | ts->pendown = (Rt != 0); | |
c9e617a5 | 451 | mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD); |
ffa458c1 DB |
452 | |
453 | spin_unlock_irqrestore(&ts->lock, flags); | |
454 | } | |
455 | ||
0b7018aa ID |
456 | static void ads7846_debounce(void *ads) |
457 | { | |
458 | struct ads7846 *ts = ads; | |
459 | struct spi_message *m; | |
460 | struct spi_transfer *t; | |
d5b415c9 | 461 | int val; |
0b7018aa ID |
462 | int status; |
463 | ||
464 | m = &ts->msg[ts->msg_idx]; | |
465 | t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list); | |
9084533e | 466 | val = (be16_to_cpu(*(__be16 *)t->rx_buf) >> 3) & 0x0fff; |
d5b415c9 ID |
467 | if (!ts->read_cnt || (abs(ts->last_read - val) > ts->debounce_tol)) { |
468 | /* Repeat it, if this was the first read or the read | |
469 | * wasn't consistent enough. */ | |
470 | if (ts->read_cnt < ts->debounce_max) { | |
471 | ts->last_read = val; | |
472 | ts->read_cnt++; | |
473 | } else { | |
474 | /* Maximum number of debouncing reached and still | |
475 | * not enough number of consistent readings. Abort | |
476 | * the whole sample, repeat it in the next sampling | |
477 | * period. | |
478 | */ | |
479 | ts->tc.ignore = 1; | |
480 | ts->read_cnt = 0; | |
481 | /* Last message will contain ads7846_rx() as the | |
482 | * completion function. | |
483 | */ | |
484 | m = ts->last_msg; | |
485 | } | |
486 | /* Start over collecting consistent readings. */ | |
487 | ts->read_rep = 0; | |
0b7018aa | 488 | } else { |
d5b415c9 ID |
489 | if (++ts->read_rep > ts->debounce_rep) { |
490 | /* Got a good reading for this coordinate, | |
491 | * go for the next one. */ | |
492 | ts->tc.ignore = 0; | |
493 | ts->msg_idx++; | |
494 | ts->read_cnt = 0; | |
495 | ts->read_rep = 0; | |
496 | m++; | |
497 | } else | |
498 | /* Read more values that are consistent. */ | |
499 | ts->read_cnt++; | |
0b7018aa ID |
500 | } |
501 | status = spi_async(ts->spi, m); | |
502 | if (status) | |
503 | dev_err(&ts->spi->dev, "spi_async --> %d\n", | |
504 | status); | |
505 | } | |
506 | ||
ffa458c1 DB |
507 | static void ads7846_timer(unsigned long handle) |
508 | { | |
509 | struct ads7846 *ts = (void *)handle; | |
510 | int status = 0; | |
0b7018aa | 511 | |
c9e617a5 ID |
512 | spin_lock_irq(&ts->lock); |
513 | ||
514 | if (unlikely(ts->msg_idx && !ts->pendown)) { | |
9084533e | 515 | /* measurement cycle ended */ |
c9e617a5 ID |
516 | if (!device_suspended(&ts->spi->dev)) { |
517 | ts->irq_disabled = 0; | |
518 | enable_irq(ts->spi->irq); | |
519 | } | |
520 | ts->pending = 0; | |
521 | ts->msg_idx = 0; | |
522 | } else { | |
523 | /* pen is still down, continue with the measurement */ | |
524 | ts->msg_idx = 0; | |
525 | status = spi_async(ts->spi, &ts->msg[0]); | |
526 | if (status) | |
527 | dev_err(&ts->spi->dev, "spi_async --> %d\n", status); | |
528 | } | |
529 | ||
530 | spin_unlock_irq(&ts->lock); | |
0b7018aa ID |
531 | } |
532 | ||
7d12e780 | 533 | static irqreturn_t ads7846_irq(int irq, void *handle) |
0b7018aa ID |
534 | { |
535 | struct ads7846 *ts = handle; | |
536 | unsigned long flags; | |
ffa458c1 DB |
537 | |
538 | spin_lock_irqsave(&ts->lock, flags); | |
c9e617a5 | 539 | if (likely(ts->get_pendown_state())) { |
ffa458c1 | 540 | if (!ts->irq_disabled) { |
9084533e DB |
541 | /* The ARM do_simple_IRQ() dispatcher doesn't act |
542 | * like the other dispatchers: it will report IRQs | |
543 | * even after they've been disabled. We work around | |
544 | * that here. (The "generic irq" framework may help...) | |
0b7018aa | 545 | */ |
ffa458c1 DB |
546 | ts->irq_disabled = 1; |
547 | disable_irq(ts->spi->irq); | |
0b7018aa ID |
548 | ts->pending = 1; |
549 | mod_timer(&ts->timer, jiffies); | |
550 | } | |
ffa458c1 DB |
551 | } |
552 | spin_unlock_irqrestore(&ts->lock, flags); | |
7de90a8c ID |
553 | |
554 | return IRQ_HANDLED; | |
ffa458c1 DB |
555 | } |
556 | ||
557 | /*--------------------------------------------------------------------------*/ | |
558 | ||
7de90a8c ID |
559 | /* Must be called with ts->lock held */ |
560 | static void ads7846_disable(struct ads7846 *ts) | |
ffa458c1 | 561 | { |
7de90a8c ID |
562 | if (ts->disabled) |
563 | return; | |
ffa458c1 | 564 | |
c9e617a5 ID |
565 | ts->disabled = 1; |
566 | ||
ffa458c1 | 567 | /* are we waiting for IRQ, or polling? */ |
c9e617a5 ID |
568 | if (!ts->pending) { |
569 | ts->irq_disabled = 1; | |
570 | disable_irq(ts->spi->irq); | |
ffa458c1 | 571 | } else { |
c9e617a5 ID |
572 | /* the timer will run at least once more, and |
573 | * leave everything in a clean state, IRQ disabled | |
ffa458c1 | 574 | */ |
c9e617a5 | 575 | while (ts->pending) { |
7de90a8c | 576 | spin_unlock_irq(&ts->lock); |
c4febb94 | 577 | msleep(1); |
7de90a8c | 578 | spin_lock_irq(&ts->lock); |
ffa458c1 DB |
579 | } |
580 | } | |
581 | ||
582 | /* we know the chip's in lowpower mode since we always | |
583 | * leave it that way after every request | |
584 | */ | |
585 | ||
7de90a8c ID |
586 | } |
587 | ||
588 | /* Must be called with ts->lock held */ | |
589 | static void ads7846_enable(struct ads7846 *ts) | |
590 | { | |
591 | if (!ts->disabled) | |
592 | return; | |
593 | ||
594 | ts->disabled = 0; | |
595 | ts->irq_disabled = 0; | |
596 | enable_irq(ts->spi->irq); | |
597 | } | |
598 | ||
599 | static int ads7846_suspend(struct spi_device *spi, pm_message_t message) | |
600 | { | |
601 | struct ads7846 *ts = dev_get_drvdata(&spi->dev); | |
602 | ||
603 | spin_lock_irq(&ts->lock); | |
604 | ||
605 | spi->dev.power.power_state = message; | |
606 | ads7846_disable(ts); | |
607 | ||
608 | spin_unlock_irq(&ts->lock); | |
609 | ||
ffa458c1 | 610 | return 0; |
7de90a8c | 611 | |
ffa458c1 DB |
612 | } |
613 | ||
2e5a7bd9 | 614 | static int ads7846_resume(struct spi_device *spi) |
ffa458c1 | 615 | { |
2e5a7bd9 | 616 | struct ads7846 *ts = dev_get_drvdata(&spi->dev); |
ffa458c1 | 617 | |
7de90a8c ID |
618 | spin_lock_irq(&ts->lock); |
619 | ||
2e5a7bd9 | 620 | spi->dev.power.power_state = PMSG_ON; |
7de90a8c ID |
621 | ads7846_enable(ts); |
622 | ||
623 | spin_unlock_irq(&ts->lock); | |
624 | ||
ffa458c1 DB |
625 | return 0; |
626 | } | |
627 | ||
2e5a7bd9 | 628 | static int __devinit ads7846_probe(struct spi_device *spi) |
ffa458c1 | 629 | { |
ffa458c1 | 630 | struct ads7846 *ts; |
a90f7e98 | 631 | struct input_dev *input_dev; |
2e5a7bd9 | 632 | struct ads7846_platform_data *pdata = spi->dev.platform_data; |
0b7018aa | 633 | struct spi_message *m; |
ffa458c1 | 634 | struct spi_transfer *x; |
a90f7e98 | 635 | int err; |
ffa458c1 DB |
636 | |
637 | if (!spi->irq) { | |
2e5a7bd9 | 638 | dev_dbg(&spi->dev, "no IRQ?\n"); |
ffa458c1 DB |
639 | return -ENODEV; |
640 | } | |
641 | ||
642 | if (!pdata) { | |
2e5a7bd9 | 643 | dev_dbg(&spi->dev, "no platform data?\n"); |
ffa458c1 DB |
644 | return -ENODEV; |
645 | } | |
646 | ||
647 | /* don't exceed max specified sample rate */ | |
d93f70b2 | 648 | if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) { |
2e5a7bd9 | 649 | dev_dbg(&spi->dev, "f(sample) %d KHz?\n", |
d93f70b2 | 650 | (spi->max_speed_hz/SAMPLE_BITS)/1000); |
ffa458c1 DB |
651 | return -EINVAL; |
652 | } | |
653 | ||
9084533e DB |
654 | /* REVISIT when the irq can be triggered active-low, or if for some |
655 | * reason the touchscreen isn't hooked up, we don't need to access | |
656 | * the pendown state. | |
657 | */ | |
c9e617a5 ID |
658 | if (pdata->get_pendown_state == NULL) { |
659 | dev_dbg(&spi->dev, "no get_pendown_state function?\n"); | |
660 | return -EINVAL; | |
661 | } | |
662 | ||
9084533e DB |
663 | /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except |
664 | * that even if the hardware can do that, the SPI controller driver | |
665 | * may not. So we stick to very-portable 8 bit words, both RX and TX. | |
ffa458c1 | 666 | */ |
9084533e | 667 | spi->bits_per_word = 8; |
ffa458c1 | 668 | |
a90f7e98 DT |
669 | ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL); |
670 | input_dev = input_allocate_device(); | |
671 | if (!ts || !input_dev) { | |
672 | err = -ENOMEM; | |
673 | goto err_free_mem; | |
674 | } | |
ffa458c1 | 675 | |
2e5a7bd9 | 676 | dev_set_drvdata(&spi->dev, ts); |
a90f7e98 | 677 | spi->dev.power.power_state = PMSG_ON; |
ffa458c1 DB |
678 | |
679 | ts->spi = spi; | |
a90f7e98 | 680 | ts->input = input_dev; |
ffa458c1 DB |
681 | |
682 | init_timer(&ts->timer); | |
683 | ts->timer.data = (unsigned long) ts; | |
684 | ts->timer.function = ads7846_timer; | |
685 | ||
7de90a8c ID |
686 | spin_lock_init(&ts->lock); |
687 | ||
ffa458c1 DB |
688 | ts->model = pdata->model ? : 7846; |
689 | ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100; | |
690 | ts->x_plate_ohms = pdata->x_plate_ohms ? : 400; | |
d5b415c9 ID |
691 | ts->pressure_max = pdata->pressure_max ? : ~0; |
692 | if (pdata->debounce_max) { | |
693 | ts->debounce_max = pdata->debounce_max; | |
694 | ts->debounce_tol = pdata->debounce_tol; | |
695 | ts->debounce_rep = pdata->debounce_rep; | |
696 | if (ts->debounce_rep > ts->debounce_max + 1) | |
697 | ts->debounce_rep = ts->debounce_max - 1; | |
698 | } else | |
699 | ts->debounce_tol = ~0; | |
c9e617a5 | 700 | ts->get_pendown_state = pdata->get_pendown_state; |
ffa458c1 | 701 | |
a90f7e98 | 702 | snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id); |
ffa458c1 | 703 | |
a90f7e98 DT |
704 | input_dev->name = "ADS784x Touchscreen"; |
705 | input_dev->phys = ts->phys; | |
706 | input_dev->cdev.dev = &spi->dev; | |
ffa458c1 | 707 | |
a90f7e98 DT |
708 | input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS); |
709 | input_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH); | |
710 | input_set_abs_params(input_dev, ABS_X, | |
ffa458c1 DB |
711 | pdata->x_min ? : 0, |
712 | pdata->x_max ? : MAX_12BIT, | |
713 | 0, 0); | |
a90f7e98 | 714 | input_set_abs_params(input_dev, ABS_Y, |
ffa458c1 DB |
715 | pdata->y_min ? : 0, |
716 | pdata->y_max ? : MAX_12BIT, | |
717 | 0, 0); | |
a90f7e98 | 718 | input_set_abs_params(input_dev, ABS_PRESSURE, |
ffa458c1 DB |
719 | pdata->pressure_min, pdata->pressure_max, 0, 0); |
720 | ||
ffa458c1 DB |
721 | /* set up the transfers to read touchscreen state; this assumes we |
722 | * use formula #2 for pressure, not #3. | |
723 | */ | |
0b7018aa | 724 | m = &ts->msg[0]; |
ffa458c1 DB |
725 | x = ts->xfer; |
726 | ||
0b7018aa ID |
727 | spi_message_init(m); |
728 | ||
ffa458c1 | 729 | /* y- still on; turn on only y+ (and ADC) */ |
d93f70b2 DB |
730 | ts->read_y = READ_Y; |
731 | x->tx_buf = &ts->read_y; | |
ffa458c1 | 732 | x->len = 1; |
0b7018aa | 733 | spi_message_add_tail(x, m); |
d93f70b2 | 734 | |
ffa458c1 DB |
735 | x++; |
736 | x->rx_buf = &ts->tc.y; | |
737 | x->len = 2; | |
0b7018aa ID |
738 | spi_message_add_tail(x, m); |
739 | ||
740 | m->complete = ads7846_debounce; | |
741 | m->context = ts; | |
742 | ||
743 | m++; | |
744 | spi_message_init(m); | |
745 | ||
746 | /* turn y- off, x+ on, then leave in lowpower */ | |
747 | x++; | |
748 | ts->read_x = READ_X; | |
749 | x->tx_buf = &ts->read_x; | |
750 | x->len = 1; | |
751 | spi_message_add_tail(x, m); | |
752 | ||
753 | x++; | |
754 | x->rx_buf = &ts->tc.x; | |
755 | x->len = 2; | |
756 | spi_message_add_tail(x, m); | |
757 | ||
758 | m->complete = ads7846_debounce; | |
759 | m->context = ts; | |
ffa458c1 DB |
760 | |
761 | /* turn y+ off, x- on; we'll use formula #2 */ | |
762 | if (ts->model == 7846) { | |
0b7018aa ID |
763 | m++; |
764 | spi_message_init(m); | |
765 | ||
d93f70b2 DB |
766 | x++; |
767 | ts->read_z1 = READ_Z1; | |
768 | x->tx_buf = &ts->read_z1; | |
ffa458c1 | 769 | x->len = 1; |
0b7018aa | 770 | spi_message_add_tail(x, m); |
d93f70b2 | 771 | |
ffa458c1 DB |
772 | x++; |
773 | x->rx_buf = &ts->tc.z1; | |
774 | x->len = 2; | |
0b7018aa ID |
775 | spi_message_add_tail(x, m); |
776 | ||
777 | m->complete = ads7846_debounce; | |
778 | m->context = ts; | |
779 | ||
780 | m++; | |
781 | spi_message_init(m); | |
ffa458c1 | 782 | |
d93f70b2 DB |
783 | x++; |
784 | ts->read_z2 = READ_Z2; | |
785 | x->tx_buf = &ts->read_z2; | |
ffa458c1 | 786 | x->len = 1; |
0b7018aa | 787 | spi_message_add_tail(x, m); |
d93f70b2 | 788 | |
ffa458c1 DB |
789 | x++; |
790 | x->rx_buf = &ts->tc.z2; | |
791 | x->len = 2; | |
0b7018aa | 792 | spi_message_add_tail(x, m); |
ffa458c1 | 793 | |
0b7018aa ID |
794 | m->complete = ads7846_debounce; |
795 | m->context = ts; | |
796 | } | |
53a0ef89 ID |
797 | |
798 | /* power down */ | |
0b7018aa ID |
799 | m++; |
800 | spi_message_init(m); | |
801 | ||
53a0ef89 ID |
802 | x++; |
803 | ts->pwrdown = PWRDOWN; | |
804 | x->tx_buf = &ts->pwrdown; | |
805 | x->len = 1; | |
0b7018aa | 806 | spi_message_add_tail(x, m); |
53a0ef89 ID |
807 | |
808 | x++; | |
809 | x->rx_buf = &ts->dummy; | |
810 | x->len = 2; | |
d93f70b2 | 811 | CS_CHANGE(*x); |
0b7018aa | 812 | spi_message_add_tail(x, m); |
ffa458c1 | 813 | |
0b7018aa ID |
814 | m->complete = ads7846_rx; |
815 | m->context = ts; | |
ffa458c1 | 816 | |
d5b415c9 ID |
817 | ts->last_msg = m; |
818 | ||
dace1453 | 819 | if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING, |
9084533e | 820 | spi->dev.driver->name, ts)) { |
2e5a7bd9 | 821 | dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq); |
a90f7e98 DT |
822 | err = -EBUSY; |
823 | goto err_free_mem; | |
ffa458c1 | 824 | } |
ffa458c1 | 825 | |
2e5a7bd9 | 826 | dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq); |
ffa458c1 DB |
827 | |
828 | /* take a first sample, leaving nPENIRQ active; avoid | |
829 | * the touchscreen, in case it's not connected. | |
830 | */ | |
2e5a7bd9 | 831 | (void) ads7846_read12_ser(&spi->dev, |
ffa458c1 DB |
832 | READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON); |
833 | ||
8dd51650 DT |
834 | switch (ts->model) { |
835 | case 7846: | |
836 | ts->attr_group = &ads7846_attr_group; | |
837 | break; | |
838 | case 7845: | |
839 | ts->attr_group = &ads7845_attr_group; | |
840 | break; | |
841 | default: | |
842 | ts->attr_group = &ads7843_attr_group; | |
843 | break; | |
ffa458c1 | 844 | } |
8dd51650 DT |
845 | err = sysfs_create_group(&spi->dev.kobj, ts->attr_group); |
846 | if (err) | |
847 | goto err_free_irq; | |
7de90a8c | 848 | |
a90f7e98 DT |
849 | err = input_register_device(input_dev); |
850 | if (err) | |
8dd51650 | 851 | goto err_remove_attr_group; |
a90f7e98 | 852 | |
ffa458c1 | 853 | return 0; |
a90f7e98 | 854 | |
8dd51650 DT |
855 | err_remove_attr_group: |
856 | sysfs_remove_group(&spi->dev.kobj, ts->attr_group); | |
857 | err_free_irq: | |
a90f7e98 DT |
858 | free_irq(spi->irq, ts); |
859 | err_free_mem: | |
860 | input_free_device(input_dev); | |
861 | kfree(ts); | |
862 | return err; | |
ffa458c1 DB |
863 | } |
864 | ||
2e5a7bd9 | 865 | static int __devexit ads7846_remove(struct spi_device *spi) |
ffa458c1 | 866 | { |
2e5a7bd9 | 867 | struct ads7846 *ts = dev_get_drvdata(&spi->dev); |
ffa458c1 | 868 | |
7de90a8c ID |
869 | input_unregister_device(ts->input); |
870 | ||
2e5a7bd9 | 871 | ads7846_suspend(spi, PMSG_SUSPEND); |
ffa458c1 | 872 | |
8dd51650 | 873 | sysfs_remove_group(&spi->dev.kobj, ts->attr_group); |
ffa458c1 | 874 | |
7de90a8c | 875 | free_irq(ts->spi->irq, ts); |
c9e617a5 ID |
876 | /* suspend left the IRQ disabled */ |
877 | enable_irq(ts->spi->irq); | |
7de90a8c | 878 | |
ffa458c1 DB |
879 | kfree(ts); |
880 | ||
2e5a7bd9 | 881 | dev_dbg(&spi->dev, "unregistered touchscreen\n"); |
ffa458c1 DB |
882 | return 0; |
883 | } | |
884 | ||
2e5a7bd9 DB |
885 | static struct spi_driver ads7846_driver = { |
886 | .driver = { | |
887 | .name = "ads7846", | |
888 | .bus = &spi_bus_type, | |
889 | .owner = THIS_MODULE, | |
890 | }, | |
ffa458c1 | 891 | .probe = ads7846_probe, |
2e5a7bd9 | 892 | .remove = __devexit_p(ads7846_remove), |
ffa458c1 DB |
893 | .suspend = ads7846_suspend, |
894 | .resume = ads7846_resume, | |
895 | }; | |
896 | ||
897 | static int __init ads7846_init(void) | |
898 | { | |
899 | /* grr, board-specific init should stay out of drivers!! */ | |
900 | ||
901 | #ifdef CONFIG_ARCH_OMAP | |
902 | if (machine_is_omap_osk()) { | |
903 | /* GPIO4 = PENIRQ; GPIO6 = BUSY */ | |
904 | omap_request_gpio(4); | |
905 | omap_set_gpio_direction(4, 1); | |
906 | omap_request_gpio(6); | |
907 | omap_set_gpio_direction(6, 1); | |
908 | } | |
909 | // also TI 1510 Innovator, bitbanging through FPGA | |
910 | // also Nokia 770 | |
911 | // also Palm Tungsten T2 | |
912 | #endif | |
913 | ||
914 | // PXA: | |
915 | // also Dell Axim X50 | |
916 | // also HP iPaq H191x/H192x/H415x/H435x | |
2e5a7bd9 | 917 | // also Intel Lubbock (additional to UCB1400; as temperature sensor) |
ffa458c1 DB |
918 | // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky) |
919 | ||
2e5a7bd9 DB |
920 | // Atmel at91sam9261-EK uses ads7843 |
921 | ||
ffa458c1 DB |
922 | // also various AMD Au1x00 devel boards |
923 | ||
2e5a7bd9 | 924 | return spi_register_driver(&ads7846_driver); |
ffa458c1 DB |
925 | } |
926 | module_init(ads7846_init); | |
927 | ||
928 | static void __exit ads7846_exit(void) | |
929 | { | |
2e5a7bd9 | 930 | spi_unregister_driver(&ads7846_driver); |
ffa458c1 DB |
931 | |
932 | #ifdef CONFIG_ARCH_OMAP | |
933 | if (machine_is_omap_osk()) { | |
934 | omap_free_gpio(4); | |
935 | omap_free_gpio(6); | |
936 | } | |
937 | #endif | |
938 | ||
939 | } | |
940 | module_exit(ads7846_exit); | |
941 | ||
942 | MODULE_DESCRIPTION("ADS7846 TouchScreen Driver"); | |
943 | MODULE_LICENSE("GPL"); |