ads7846.c 27 KB

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  1. /*
  2. * ADS7846 based touchscreen and sensor driver
  3. *
  4. * Copyright (c) 2005 David Brownell
  5. * Copyright (c) 2006 Nokia Corporation
  6. * Various changes: Imre Deak <imre.deak@nokia.com>
  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/hwmon.h>
  21. #include <linux/init.h>
  22. #include <linux/err.h>
  23. #include <linux/delay.h>
  24. #include <linux/input.h>
  25. #include <linux/interrupt.h>
  26. #include <linux/slab.h>
  27. #include <linux/spi/spi.h>
  28. #include <linux/spi/ads7846.h>
  29. #include <asm/irq.h>
  30. #ifdef CONFIG_ARM
  31. #include <asm/mach-types.h>
  32. #ifdef CONFIG_ARCH_OMAP
  33. #include <asm/arch/gpio.h>
  34. #endif
  35. #endif
  36. /*
  37. * This code has been heavily tested on a Nokia 770, and lightly
  38. * tested on other ads7846 devices (OSK/Mistral, Lubbock).
  39. * Support for ads7843 and ads7845 has only been stubbed in.
  40. *
  41. * IRQ handling needs a workaround because of a shortcoming in handling
  42. * edge triggered IRQs on some platforms like the OMAP1/2. These
  43. * platforms don't handle the ARM lazy IRQ disabling properly, thus we
  44. * have to maintain our own SW IRQ disabled status. This should be
  45. * removed as soon as the affected platform's IRQ handling is fixed.
  46. *
  47. * app note sbaa036 talks in more detail about accurate sampling...
  48. * that ought to help in situations like LCDs inducing noise (which
  49. * can also be helped by using synch signals) and more generally.
  50. * This driver tries to utilize the measures described in the app
  51. * note. The strength of filtering can be set in the board-* specific
  52. * files.
  53. */
  54. #define TS_POLL_DELAY (1 * 1000000) /* ns delay before the first sample */
  55. #define TS_POLL_PERIOD (5 * 1000000) /* ns delay between samples */
  56. /* this driver doesn't aim at the peak continuous sample rate */
  57. #define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
  58. struct ts_event {
  59. /* For portability, we can't read 12 bit values using SPI (which
  60. * would make the controller deliver them as native byteorder u16
  61. * with msbs zeroed). Instead, we read them as two 8-bit values,
  62. * *** WHICH NEED BYTESWAPPING *** and range adjustment.
  63. */
  64. u16 x;
  65. u16 y;
  66. u16 z1, z2;
  67. int ignore;
  68. };
  69. struct ads7846 {
  70. struct input_dev *input;
  71. char phys[32];
  72. struct spi_device *spi;
  73. #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
  74. struct attribute_group *attr_group;
  75. struct class_device *hwmon;
  76. #endif
  77. u16 model;
  78. u16 vref_delay_usecs;
  79. u16 x_plate_ohms;
  80. u16 pressure_max;
  81. u8 read_x, read_y, read_z1, read_z2, pwrdown;
  82. u16 dummy; /* for the pwrdown read */
  83. struct ts_event tc;
  84. struct spi_transfer xfer[10];
  85. struct spi_message msg[5];
  86. struct spi_message *last_msg;
  87. int msg_idx;
  88. int read_cnt;
  89. int read_rep;
  90. int last_read;
  91. u16 debounce_max;
  92. u16 debounce_tol;
  93. u16 debounce_rep;
  94. spinlock_t lock;
  95. struct hrtimer timer;
  96. unsigned pendown:1; /* P: lock */
  97. unsigned pending:1; /* P: lock */
  98. // FIXME remove "irq_disabled"
  99. unsigned irq_disabled:1; /* P: lock */
  100. unsigned disabled:1;
  101. int (*filter)(void *data, int data_idx, int *val);
  102. void *filter_data;
  103. void (*filter_cleanup)(void *data);
  104. int (*get_pendown_state)(void);
  105. };
  106. /* leave chip selected when we're done, for quicker re-select? */
  107. #if 0
  108. #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
  109. #else
  110. #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
  111. #endif
  112. /*--------------------------------------------------------------------------*/
  113. /* The ADS7846 has touchscreen and other sensors.
  114. * Earlier ads784x chips are somewhat compatible.
  115. */
  116. #define ADS_START (1 << 7)
  117. #define ADS_A2A1A0_d_y (1 << 4) /* differential */
  118. #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
  119. #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
  120. #define ADS_A2A1A0_d_x (5 << 4) /* differential */
  121. #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
  122. #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
  123. #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
  124. #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
  125. #define ADS_8_BIT (1 << 3)
  126. #define ADS_12_BIT (0 << 3)
  127. #define ADS_SER (1 << 2) /* non-differential */
  128. #define ADS_DFR (0 << 2) /* differential */
  129. #define ADS_PD10_PDOWN (0 << 0) /* lowpower mode + penirq */
  130. #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
  131. #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
  132. #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
  133. #define MAX_12BIT ((1<<12)-1)
  134. /* leave ADC powered up (disables penirq) between differential samples */
  135. #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
  136. | ADS_12_BIT | ADS_DFR | \
  137. (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
  138. #define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref))
  139. #define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref))
  140. #define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref))
  141. #define READ_X(vref) (READ_12BIT_DFR(x, 1, vref))
  142. #define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */
  143. /* single-ended samples need to first power up reference voltage;
  144. * we leave both ADC and VREF powered
  145. */
  146. #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
  147. | ADS_12_BIT | ADS_SER)
  148. #define REF_ON (READ_12BIT_DFR(x, 1, 1))
  149. #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
  150. /*--------------------------------------------------------------------------*/
  151. /*
  152. * Non-touchscreen sensors only use single-ended conversions.
  153. * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
  154. * ads7846 lets that pin be unconnected, to use internal vREF.
  155. */
  156. static unsigned vREF_mV;
  157. module_param(vREF_mV, uint, 0);
  158. MODULE_PARM_DESC(vREF_mV, "external vREF voltage, in milliVolts");
  159. struct ser_req {
  160. u8 ref_on;
  161. u8 command;
  162. u8 ref_off;
  163. u16 scratch;
  164. __be16 sample;
  165. struct spi_message msg;
  166. struct spi_transfer xfer[6];
  167. };
  168. static void ads7846_enable(struct ads7846 *ts);
  169. static void ads7846_disable(struct ads7846 *ts);
  170. static int device_suspended(struct device *dev)
  171. {
  172. struct ads7846 *ts = dev_get_drvdata(dev);
  173. return dev->power.power_state.event != PM_EVENT_ON || ts->disabled;
  174. }
  175. static int ads7846_read12_ser(struct device *dev, unsigned command)
  176. {
  177. struct spi_device *spi = to_spi_device(dev);
  178. struct ads7846 *ts = dev_get_drvdata(dev);
  179. struct ser_req *req = kzalloc(sizeof *req, GFP_KERNEL);
  180. int status;
  181. int sample;
  182. int use_internal;
  183. if (!req)
  184. return -ENOMEM;
  185. spi_message_init(&req->msg);
  186. /* FIXME boards with ads7846 might use external vref instead ... */
  187. use_internal = (ts->model == 7846);
  188. /* maybe turn on internal vREF, and let it settle */
  189. if (use_internal) {
  190. req->ref_on = REF_ON;
  191. req->xfer[0].tx_buf = &req->ref_on;
  192. req->xfer[0].len = 1;
  193. spi_message_add_tail(&req->xfer[0], &req->msg);
  194. req->xfer[1].rx_buf = &req->scratch;
  195. req->xfer[1].len = 2;
  196. /* for 1uF, settle for 800 usec; no cap, 100 usec. */
  197. req->xfer[1].delay_usecs = ts->vref_delay_usecs;
  198. spi_message_add_tail(&req->xfer[1], &req->msg);
  199. }
  200. /* take sample */
  201. req->command = (u8) command;
  202. req->xfer[2].tx_buf = &req->command;
  203. req->xfer[2].len = 1;
  204. spi_message_add_tail(&req->xfer[2], &req->msg);
  205. req->xfer[3].rx_buf = &req->sample;
  206. req->xfer[3].len = 2;
  207. spi_message_add_tail(&req->xfer[3], &req->msg);
  208. /* REVISIT: take a few more samples, and compare ... */
  209. /* maybe off internal vREF */
  210. if (use_internal) {
  211. req->ref_off = REF_OFF;
  212. req->xfer[4].tx_buf = &req->ref_off;
  213. req->xfer[4].len = 1;
  214. spi_message_add_tail(&req->xfer[4], &req->msg);
  215. req->xfer[5].rx_buf = &req->scratch;
  216. req->xfer[5].len = 2;
  217. CS_CHANGE(req->xfer[5]);
  218. spi_message_add_tail(&req->xfer[5], &req->msg);
  219. }
  220. ts->irq_disabled = 1;
  221. disable_irq(spi->irq);
  222. status = spi_sync(spi, &req->msg);
  223. ts->irq_disabled = 0;
  224. enable_irq(spi->irq);
  225. if (req->msg.status)
  226. status = req->msg.status;
  227. /* on-wire is a must-ignore bit, a BE12 value, then padding */
  228. sample = be16_to_cpu(req->sample);
  229. sample = sample >> 3;
  230. sample &= 0x0fff;
  231. kfree(req);
  232. return status ? status : sample;
  233. }
  234. #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
  235. #define SHOW(name, var, adjust) static ssize_t \
  236. name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
  237. { \
  238. struct ads7846 *ts = dev_get_drvdata(dev); \
  239. ssize_t v = ads7846_read12_ser(dev, \
  240. READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \
  241. if (v < 0) \
  242. return v; \
  243. return sprintf(buf, "%u\n", adjust(ts, v)); \
  244. } \
  245. static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
  246. /* Sysfs conventions report temperatures in millidegrees Celcius.
  247. * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
  248. * accuracy scheme without calibration data. For now we won't try either;
  249. * userspace sees raw sensor values, and must scale/calibrate appropriately.
  250. */
  251. static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
  252. {
  253. return v;
  254. }
  255. SHOW(temp0, temp0, null_adjust) /* temp1_input */
  256. SHOW(temp1, temp1, null_adjust) /* temp2_input */
  257. /* sysfs conventions report voltages in millivolts. We can convert voltages
  258. * if we know vREF. userspace may need to scale vAUX to match the board's
  259. * external resistors; we assume that vBATT only uses the internal ones.
  260. */
  261. static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
  262. {
  263. unsigned retval = v;
  264. /* external resistors may scale vAUX into 0..vREF */
  265. retval *= vREF_mV;
  266. retval = retval >> 12;
  267. return retval;
  268. }
  269. static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
  270. {
  271. unsigned retval = vaux_adjust(ts, v);
  272. /* ads7846 has a resistor ladder to scale this signal down */
  273. if (ts->model == 7846)
  274. retval *= 4;
  275. return retval;
  276. }
  277. SHOW(in0_input, vaux, vaux_adjust)
  278. SHOW(in1_input, vbatt, vbatt_adjust)
  279. static struct attribute *ads7846_attributes[] = {
  280. &dev_attr_temp0.attr,
  281. &dev_attr_temp1.attr,
  282. &dev_attr_in0_input.attr,
  283. &dev_attr_in1_input.attr,
  284. NULL,
  285. };
  286. static struct attribute_group ads7846_attr_group = {
  287. .attrs = ads7846_attributes,
  288. };
  289. static struct attribute *ads7843_attributes[] = {
  290. &dev_attr_in0_input.attr,
  291. &dev_attr_in1_input.attr,
  292. NULL,
  293. };
  294. static struct attribute_group ads7843_attr_group = {
  295. .attrs = ads7843_attributes,
  296. };
  297. static struct attribute *ads7845_attributes[] = {
  298. &dev_attr_in0_input.attr,
  299. NULL,
  300. };
  301. static struct attribute_group ads7845_attr_group = {
  302. .attrs = ads7845_attributes,
  303. };
  304. static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
  305. {
  306. struct class_device *hwmon;
  307. int err;
  308. /* hwmon sensors need a reference voltage */
  309. switch (ts->model) {
  310. case 7846:
  311. if (!vREF_mV) {
  312. dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
  313. vREF_mV = 2500;
  314. }
  315. break;
  316. case 7845:
  317. case 7843:
  318. if (!vREF_mV) {
  319. dev_warn(&spi->dev,
  320. "external vREF for ADS%d not specified\n",
  321. ts->model);
  322. return 0;
  323. }
  324. break;
  325. }
  326. /* different chips have different sensor groups */
  327. switch (ts->model) {
  328. case 7846:
  329. ts->attr_group = &ads7846_attr_group;
  330. break;
  331. case 7845:
  332. ts->attr_group = &ads7845_attr_group;
  333. break;
  334. case 7843:
  335. ts->attr_group = &ads7843_attr_group;
  336. break;
  337. default:
  338. dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
  339. return 0;
  340. }
  341. err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
  342. if (err)
  343. return err;
  344. hwmon = hwmon_device_register(&spi->dev);
  345. if (IS_ERR(hwmon)) {
  346. sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
  347. return PTR_ERR(hwmon);
  348. }
  349. ts->hwmon = hwmon;
  350. return 0;
  351. }
  352. static void ads784x_hwmon_unregister(struct spi_device *spi,
  353. struct ads7846 *ts)
  354. {
  355. if (ts->hwmon) {
  356. sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
  357. hwmon_device_unregister(ts->hwmon);
  358. }
  359. }
  360. #else
  361. static inline int ads784x_hwmon_register(struct spi_device *spi,
  362. struct ads7846 *ts)
  363. {
  364. return 0;
  365. }
  366. static inline void ads784x_hwmon_unregister(struct spi_device *spi,
  367. struct ads7846 *ts)
  368. {
  369. }
  370. #endif
  371. static int is_pen_down(struct device *dev)
  372. {
  373. struct ads7846 *ts = dev_get_drvdata(dev);
  374. return ts->pendown;
  375. }
  376. static ssize_t ads7846_pen_down_show(struct device *dev,
  377. struct device_attribute *attr, char *buf)
  378. {
  379. return sprintf(buf, "%u\n", is_pen_down(dev));
  380. }
  381. static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
  382. static ssize_t ads7846_disable_show(struct device *dev,
  383. struct device_attribute *attr, char *buf)
  384. {
  385. struct ads7846 *ts = dev_get_drvdata(dev);
  386. return sprintf(buf, "%u\n", ts->disabled);
  387. }
  388. static ssize_t ads7846_disable_store(struct device *dev,
  389. struct device_attribute *attr,
  390. const char *buf, size_t count)
  391. {
  392. struct ads7846 *ts = dev_get_drvdata(dev);
  393. char *endp;
  394. int i;
  395. i = simple_strtoul(buf, &endp, 10);
  396. spin_lock_irq(&ts->lock);
  397. if (i)
  398. ads7846_disable(ts);
  399. else
  400. ads7846_enable(ts);
  401. spin_unlock_irq(&ts->lock);
  402. return count;
  403. }
  404. static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
  405. static struct attribute *ads784x_attributes[] = {
  406. &dev_attr_pen_down.attr,
  407. &dev_attr_disable.attr,
  408. NULL,
  409. };
  410. static struct attribute_group ads784x_attr_group = {
  411. .attrs = ads784x_attributes,
  412. };
  413. /*--------------------------------------------------------------------------*/
  414. /*
  415. * PENIRQ only kicks the timer. The timer only reissues the SPI transfer,
  416. * to retrieve touchscreen status.
  417. *
  418. * The SPI transfer completion callback does the real work. It reports
  419. * touchscreen events and reactivates the timer (or IRQ) as appropriate.
  420. */
  421. static void ads7846_rx(void *ads)
  422. {
  423. struct ads7846 *ts = ads;
  424. unsigned Rt;
  425. u16 x, y, z1, z2;
  426. /* ads7846_rx_val() did in-place conversion (including byteswap) from
  427. * on-the-wire format as part of debouncing to get stable readings.
  428. */
  429. x = ts->tc.x;
  430. y = ts->tc.y;
  431. z1 = ts->tc.z1;
  432. z2 = ts->tc.z2;
  433. /* range filtering */
  434. if (x == MAX_12BIT)
  435. x = 0;
  436. if (likely(x && z1)) {
  437. /* compute touch pressure resistance using equation #2 */
  438. Rt = z2;
  439. Rt -= z1;
  440. Rt *= x;
  441. Rt *= ts->x_plate_ohms;
  442. Rt /= z1;
  443. Rt = (Rt + 2047) >> 12;
  444. } else
  445. Rt = 0;
  446. /* Sample found inconsistent by debouncing or pressure is beyond
  447. * the maximum. Don't report it to user space, repeat at least
  448. * once more the measurement
  449. */
  450. if (ts->tc.ignore || Rt > ts->pressure_max) {
  451. #ifdef VERBOSE
  452. pr_debug("%s: ignored %d pressure %d\n",
  453. ts->spi->dev.bus_id, ts->tc.ignore, Rt);
  454. #endif
  455. hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
  456. HRTIMER_MODE_REL);
  457. return;
  458. }
  459. /* NOTE: We can't rely on the pressure to determine the pen down
  460. * state, even this controller has a pressure sensor. The pressure
  461. * value can fluctuate for quite a while after lifting the pen and
  462. * in some cases may not even settle at the expected value.
  463. *
  464. * The only safe way to check for the pen up condition is in the
  465. * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
  466. */
  467. if (Rt) {
  468. struct input_dev *input = ts->input;
  469. if (!ts->pendown) {
  470. input_report_key(input, BTN_TOUCH, 1);
  471. ts->pendown = 1;
  472. #ifdef VERBOSE
  473. dev_dbg(&ts->spi->dev, "DOWN\n");
  474. #endif
  475. }
  476. input_report_abs(input, ABS_X, x);
  477. input_report_abs(input, ABS_Y, y);
  478. input_report_abs(input, ABS_PRESSURE, Rt);
  479. input_sync(input);
  480. #ifdef VERBOSE
  481. dev_dbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
  482. #endif
  483. }
  484. hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
  485. HRTIMER_MODE_REL);
  486. }
  487. static int ads7846_debounce(void *ads, int data_idx, int *val)
  488. {
  489. struct ads7846 *ts = ads;
  490. if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
  491. /* Start over collecting consistent readings. */
  492. ts->read_rep = 0;
  493. /* Repeat it, if this was the first read or the read
  494. * wasn't consistent enough. */
  495. if (ts->read_cnt < ts->debounce_max) {
  496. ts->last_read = *val;
  497. ts->read_cnt++;
  498. return ADS7846_FILTER_REPEAT;
  499. } else {
  500. /* Maximum number of debouncing reached and still
  501. * not enough number of consistent readings. Abort
  502. * the whole sample, repeat it in the next sampling
  503. * period.
  504. */
  505. ts->read_cnt = 0;
  506. return ADS7846_FILTER_IGNORE;
  507. }
  508. } else {
  509. if (++ts->read_rep > ts->debounce_rep) {
  510. /* Got a good reading for this coordinate,
  511. * go for the next one. */
  512. ts->read_cnt = 0;
  513. ts->read_rep = 0;
  514. return ADS7846_FILTER_OK;
  515. } else {
  516. /* Read more values that are consistent. */
  517. ts->read_cnt++;
  518. return ADS7846_FILTER_REPEAT;
  519. }
  520. }
  521. }
  522. static int ads7846_no_filter(void *ads, int data_idx, int *val)
  523. {
  524. return ADS7846_FILTER_OK;
  525. }
  526. static void ads7846_rx_val(void *ads)
  527. {
  528. struct ads7846 *ts = ads;
  529. struct spi_message *m;
  530. struct spi_transfer *t;
  531. u16 *rx_val;
  532. int val;
  533. int action;
  534. int status;
  535. m = &ts->msg[ts->msg_idx];
  536. t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
  537. rx_val = t->rx_buf;
  538. /* adjust: on-wire is a must-ignore bit, a BE12 value, then padding;
  539. * built from two 8 bit values written msb-first.
  540. */
  541. val = be16_to_cpu(*rx_val) >> 3;
  542. action = ts->filter(ts->filter_data, ts->msg_idx, &val);
  543. switch (action) {
  544. case ADS7846_FILTER_REPEAT:
  545. break;
  546. case ADS7846_FILTER_IGNORE:
  547. ts->tc.ignore = 1;
  548. /* Last message will contain ads7846_rx() as the
  549. * completion function.
  550. */
  551. m = ts->last_msg;
  552. break;
  553. case ADS7846_FILTER_OK:
  554. *rx_val = val;
  555. ts->tc.ignore = 0;
  556. m = &ts->msg[++ts->msg_idx];
  557. break;
  558. default:
  559. BUG();
  560. }
  561. status = spi_async(ts->spi, m);
  562. if (status)
  563. dev_err(&ts->spi->dev, "spi_async --> %d\n",
  564. status);
  565. }
  566. static enum hrtimer_restart ads7846_timer(struct hrtimer *handle)
  567. {
  568. struct ads7846 *ts = container_of(handle, struct ads7846, timer);
  569. int status = 0;
  570. spin_lock_irq(&ts->lock);
  571. if (unlikely(!ts->get_pendown_state() ||
  572. device_suspended(&ts->spi->dev))) {
  573. if (ts->pendown) {
  574. struct input_dev *input = ts->input;
  575. input_report_key(input, BTN_TOUCH, 0);
  576. input_report_abs(input, ABS_PRESSURE, 0);
  577. input_sync(input);
  578. ts->pendown = 0;
  579. #ifdef VERBOSE
  580. dev_dbg(&ts->spi->dev, "UP\n");
  581. #endif
  582. }
  583. /* measurement cycle ended */
  584. if (!device_suspended(&ts->spi->dev)) {
  585. ts->irq_disabled = 0;
  586. enable_irq(ts->spi->irq);
  587. }
  588. ts->pending = 0;
  589. } else {
  590. /* pen is still down, continue with the measurement */
  591. ts->msg_idx = 0;
  592. status = spi_async(ts->spi, &ts->msg[0]);
  593. if (status)
  594. dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
  595. }
  596. spin_unlock_irq(&ts->lock);
  597. return HRTIMER_NORESTART;
  598. }
  599. static irqreturn_t ads7846_irq(int irq, void *handle)
  600. {
  601. struct ads7846 *ts = handle;
  602. unsigned long flags;
  603. spin_lock_irqsave(&ts->lock, flags);
  604. if (likely(ts->get_pendown_state())) {
  605. if (!ts->irq_disabled) {
  606. /* The ARM do_simple_IRQ() dispatcher doesn't act
  607. * like the other dispatchers: it will report IRQs
  608. * even after they've been disabled. We work around
  609. * that here. (The "generic irq" framework may help...)
  610. */
  611. ts->irq_disabled = 1;
  612. disable_irq(ts->spi->irq);
  613. ts->pending = 1;
  614. hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY),
  615. HRTIMER_MODE_REL);
  616. }
  617. }
  618. spin_unlock_irqrestore(&ts->lock, flags);
  619. return IRQ_HANDLED;
  620. }
  621. /*--------------------------------------------------------------------------*/
  622. /* Must be called with ts->lock held */
  623. static void ads7846_disable(struct ads7846 *ts)
  624. {
  625. if (ts->disabled)
  626. return;
  627. ts->disabled = 1;
  628. /* are we waiting for IRQ, or polling? */
  629. if (!ts->pending) {
  630. ts->irq_disabled = 1;
  631. disable_irq(ts->spi->irq);
  632. } else {
  633. /* the timer will run at least once more, and
  634. * leave everything in a clean state, IRQ disabled
  635. */
  636. while (ts->pending) {
  637. spin_unlock_irq(&ts->lock);
  638. msleep(1);
  639. spin_lock_irq(&ts->lock);
  640. }
  641. }
  642. /* we know the chip's in lowpower mode since we always
  643. * leave it that way after every request
  644. */
  645. }
  646. /* Must be called with ts->lock held */
  647. static void ads7846_enable(struct ads7846 *ts)
  648. {
  649. if (!ts->disabled)
  650. return;
  651. ts->disabled = 0;
  652. ts->irq_disabled = 0;
  653. enable_irq(ts->spi->irq);
  654. }
  655. static int ads7846_suspend(struct spi_device *spi, pm_message_t message)
  656. {
  657. struct ads7846 *ts = dev_get_drvdata(&spi->dev);
  658. spin_lock_irq(&ts->lock);
  659. spi->dev.power.power_state = message;
  660. ads7846_disable(ts);
  661. spin_unlock_irq(&ts->lock);
  662. return 0;
  663. }
  664. static int ads7846_resume(struct spi_device *spi)
  665. {
  666. struct ads7846 *ts = dev_get_drvdata(&spi->dev);
  667. spin_lock_irq(&ts->lock);
  668. spi->dev.power.power_state = PMSG_ON;
  669. ads7846_enable(ts);
  670. spin_unlock_irq(&ts->lock);
  671. return 0;
  672. }
  673. static int __devinit ads7846_probe(struct spi_device *spi)
  674. {
  675. struct ads7846 *ts;
  676. struct input_dev *input_dev;
  677. struct ads7846_platform_data *pdata = spi->dev.platform_data;
  678. struct spi_message *m;
  679. struct spi_transfer *x;
  680. int vref;
  681. int err;
  682. if (!spi->irq) {
  683. dev_dbg(&spi->dev, "no IRQ?\n");
  684. return -ENODEV;
  685. }
  686. if (!pdata) {
  687. dev_dbg(&spi->dev, "no platform data?\n");
  688. return -ENODEV;
  689. }
  690. /* don't exceed max specified sample rate */
  691. if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
  692. dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
  693. (spi->max_speed_hz/SAMPLE_BITS)/1000);
  694. return -EINVAL;
  695. }
  696. /* REVISIT when the irq can be triggered active-low, or if for some
  697. * reason the touchscreen isn't hooked up, we don't need to access
  698. * the pendown state.
  699. */
  700. if (pdata->get_pendown_state == NULL) {
  701. dev_dbg(&spi->dev, "no get_pendown_state function?\n");
  702. return -EINVAL;
  703. }
  704. /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except
  705. * that even if the hardware can do that, the SPI controller driver
  706. * may not. So we stick to very-portable 8 bit words, both RX and TX.
  707. */
  708. spi->bits_per_word = 8;
  709. spi->mode = SPI_MODE_1;
  710. err = spi_setup(spi);
  711. if (err < 0)
  712. return err;
  713. ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
  714. input_dev = input_allocate_device();
  715. if (!ts || !input_dev) {
  716. err = -ENOMEM;
  717. goto err_free_mem;
  718. }
  719. dev_set_drvdata(&spi->dev, ts);
  720. spi->dev.power.power_state = PMSG_ON;
  721. ts->spi = spi;
  722. ts->input = input_dev;
  723. hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
  724. ts->timer.function = ads7846_timer;
  725. spin_lock_init(&ts->lock);
  726. ts->model = pdata->model ? : 7846;
  727. ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
  728. ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
  729. ts->pressure_max = pdata->pressure_max ? : ~0;
  730. if (pdata->filter != NULL) {
  731. if (pdata->filter_init != NULL) {
  732. err = pdata->filter_init(pdata, &ts->filter_data);
  733. if (err < 0)
  734. goto err_free_mem;
  735. }
  736. ts->filter = pdata->filter;
  737. ts->filter_cleanup = pdata->filter_cleanup;
  738. } else if (pdata->debounce_max) {
  739. ts->debounce_max = pdata->debounce_max;
  740. if (ts->debounce_max < 2)
  741. ts->debounce_max = 2;
  742. ts->debounce_tol = pdata->debounce_tol;
  743. ts->debounce_rep = pdata->debounce_rep;
  744. ts->filter = ads7846_debounce;
  745. ts->filter_data = ts;
  746. } else
  747. ts->filter = ads7846_no_filter;
  748. ts->get_pendown_state = pdata->get_pendown_state;
  749. snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
  750. input_dev->name = "ADS784x Touchscreen";
  751. input_dev->phys = ts->phys;
  752. input_dev->cdev.dev = &spi->dev;
  753. input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
  754. input_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
  755. input_set_abs_params(input_dev, ABS_X,
  756. pdata->x_min ? : 0,
  757. pdata->x_max ? : MAX_12BIT,
  758. 0, 0);
  759. input_set_abs_params(input_dev, ABS_Y,
  760. pdata->y_min ? : 0,
  761. pdata->y_max ? : MAX_12BIT,
  762. 0, 0);
  763. input_set_abs_params(input_dev, ABS_PRESSURE,
  764. pdata->pressure_min, pdata->pressure_max, 0, 0);
  765. vref = pdata->keep_vref_on;
  766. /* set up the transfers to read touchscreen state; this assumes we
  767. * use formula #2 for pressure, not #3.
  768. */
  769. m = &ts->msg[0];
  770. x = ts->xfer;
  771. spi_message_init(m);
  772. /* y- still on; turn on only y+ (and ADC) */
  773. ts->read_y = READ_Y(vref);
  774. x->tx_buf = &ts->read_y;
  775. x->len = 1;
  776. spi_message_add_tail(x, m);
  777. x++;
  778. x->rx_buf = &ts->tc.y;
  779. x->len = 2;
  780. spi_message_add_tail(x, m);
  781. m->complete = ads7846_rx_val;
  782. m->context = ts;
  783. m++;
  784. spi_message_init(m);
  785. /* turn y- off, x+ on, then leave in lowpower */
  786. x++;
  787. ts->read_x = READ_X(vref);
  788. x->tx_buf = &ts->read_x;
  789. x->len = 1;
  790. spi_message_add_tail(x, m);
  791. x++;
  792. x->rx_buf = &ts->tc.x;
  793. x->len = 2;
  794. spi_message_add_tail(x, m);
  795. m->complete = ads7846_rx_val;
  796. m->context = ts;
  797. /* turn y+ off, x- on; we'll use formula #2 */
  798. if (ts->model == 7846) {
  799. m++;
  800. spi_message_init(m);
  801. x++;
  802. ts->read_z1 = READ_Z1(vref);
  803. x->tx_buf = &ts->read_z1;
  804. x->len = 1;
  805. spi_message_add_tail(x, m);
  806. x++;
  807. x->rx_buf = &ts->tc.z1;
  808. x->len = 2;
  809. spi_message_add_tail(x, m);
  810. m->complete = ads7846_rx_val;
  811. m->context = ts;
  812. m++;
  813. spi_message_init(m);
  814. x++;
  815. ts->read_z2 = READ_Z2(vref);
  816. x->tx_buf = &ts->read_z2;
  817. x->len = 1;
  818. spi_message_add_tail(x, m);
  819. x++;
  820. x->rx_buf = &ts->tc.z2;
  821. x->len = 2;
  822. spi_message_add_tail(x, m);
  823. m->complete = ads7846_rx_val;
  824. m->context = ts;
  825. }
  826. /* power down */
  827. m++;
  828. spi_message_init(m);
  829. x++;
  830. ts->pwrdown = PWRDOWN;
  831. x->tx_buf = &ts->pwrdown;
  832. x->len = 1;
  833. spi_message_add_tail(x, m);
  834. x++;
  835. x->rx_buf = &ts->dummy;
  836. x->len = 2;
  837. CS_CHANGE(*x);
  838. spi_message_add_tail(x, m);
  839. m->complete = ads7846_rx;
  840. m->context = ts;
  841. ts->last_msg = m;
  842. if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING,
  843. spi->dev.driver->name, ts)) {
  844. dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
  845. err = -EBUSY;
  846. goto err_cleanup_filter;
  847. }
  848. err = ads784x_hwmon_register(spi, ts);
  849. if (err)
  850. goto err_free_irq;
  851. dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
  852. /* take a first sample, leaving nPENIRQ active and vREF off; avoid
  853. * the touchscreen, in case it's not connected.
  854. */
  855. (void) ads7846_read12_ser(&spi->dev,
  856. READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
  857. err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
  858. if (err)
  859. goto err_remove_hwmon;
  860. err = input_register_device(input_dev);
  861. if (err)
  862. goto err_remove_attr_group;
  863. return 0;
  864. err_remove_attr_group:
  865. sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
  866. err_remove_hwmon:
  867. ads784x_hwmon_unregister(spi, ts);
  868. err_free_irq:
  869. free_irq(spi->irq, ts);
  870. err_cleanup_filter:
  871. if (ts->filter_cleanup)
  872. ts->filter_cleanup(ts->filter_data);
  873. err_free_mem:
  874. input_free_device(input_dev);
  875. kfree(ts);
  876. return err;
  877. }
  878. static int __devexit ads7846_remove(struct spi_device *spi)
  879. {
  880. struct ads7846 *ts = dev_get_drvdata(&spi->dev);
  881. ads784x_hwmon_unregister(spi, ts);
  882. input_unregister_device(ts->input);
  883. ads7846_suspend(spi, PMSG_SUSPEND);
  884. sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
  885. free_irq(ts->spi->irq, ts);
  886. /* suspend left the IRQ disabled */
  887. enable_irq(ts->spi->irq);
  888. if (ts->filter_cleanup)
  889. ts->filter_cleanup(ts->filter_data);
  890. kfree(ts);
  891. dev_dbg(&spi->dev, "unregistered touchscreen\n");
  892. return 0;
  893. }
  894. static struct spi_driver ads7846_driver = {
  895. .driver = {
  896. .name = "ads7846",
  897. .bus = &spi_bus_type,
  898. .owner = THIS_MODULE,
  899. },
  900. .probe = ads7846_probe,
  901. .remove = __devexit_p(ads7846_remove),
  902. .suspend = ads7846_suspend,
  903. .resume = ads7846_resume,
  904. };
  905. static int __init ads7846_init(void)
  906. {
  907. /* grr, board-specific init should stay out of drivers!! */
  908. #ifdef CONFIG_ARCH_OMAP
  909. if (machine_is_omap_osk()) {
  910. /* GPIO4 = PENIRQ; GPIO6 = BUSY */
  911. omap_request_gpio(4);
  912. omap_set_gpio_direction(4, 1);
  913. omap_request_gpio(6);
  914. omap_set_gpio_direction(6, 1);
  915. }
  916. // also TI 1510 Innovator, bitbanging through FPGA
  917. // also Nokia 770
  918. // also Palm Tungsten T2
  919. #endif
  920. // PXA:
  921. // also Dell Axim X50
  922. // also HP iPaq H191x/H192x/H415x/H435x
  923. // also Intel Lubbock (additional to UCB1400; as temperature sensor)
  924. // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky)
  925. // Atmel at91sam9261-EK uses ads7843
  926. // also various AMD Au1x00 devel boards
  927. return spi_register_driver(&ads7846_driver);
  928. }
  929. module_init(ads7846_init);
  930. static void __exit ads7846_exit(void)
  931. {
  932. spi_unregister_driver(&ads7846_driver);
  933. #ifdef CONFIG_ARCH_OMAP
  934. if (machine_is_omap_osk()) {
  935. omap_free_gpio(4);
  936. omap_free_gpio(6);
  937. }
  938. #endif
  939. }
  940. module_exit(ads7846_exit);
  941. MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
  942. MODULE_LICENSE("GPL");