/* * ADS7846 based touchscreen and sensor driver * * Copyright (c) 2005 David Brownell * Copyright (c) 2006 Nokia Corporation * Various changes: Imre Deak * * Using code from: * - corgi_ts.c * Copyright (C) 2004-2005 Richard Purdie * - omap_ts.[hc], ads7846.h, ts_osk.c * Copyright (C) 2002 MontaVista Software * Copyright (C) 2004 Texas Instruments * Copyright (C) 2005 Dirk Behme * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include #include #include #include #include #include #include #include #include #include #include #include /* * This code has been heavily tested on a Nokia 770, and lightly * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz). * TSC2046 is just newer ads7846 silicon. * Support for ads7843 tested on Atmel at91sam926x-EK. * Support for ads7845 has only been stubbed in. * Support for Analog Devices AD7873 and AD7843 tested. * * IRQ handling needs a workaround because of a shortcoming in handling * edge triggered IRQs on some platforms like the OMAP1/2. These * platforms don't handle the ARM lazy IRQ disabling properly, thus we * have to maintain our own SW IRQ disabled status. This should be * removed as soon as the affected platform's IRQ handling is fixed. * * App note sbaa036 talks in more detail about accurate sampling... * that ought to help in situations like LCDs inducing noise (which * can also be helped by using synch signals) and more generally. * This driver tries to utilize the measures described in the app * note. The strength of filtering can be set in the board-* specific * files. */ #define TS_POLL_DELAY (1 * 1000000) /* ns delay before the first sample */ #define TS_POLL_PERIOD (5 * 1000000) /* ns delay between samples */ /* this driver doesn't aim at the peak continuous sample rate */ #define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */) struct ts_event { /* For portability, we can't read 12 bit values using SPI (which * would make the controller deliver them as native byteorder u16 * with msbs zeroed). Instead, we read them as two 8-bit values, * *** WHICH NEED BYTESWAPPING *** and range adjustment. */ u16 x; u16 y; u16 z1, z2; int ignore; }; /* * We allocate this separately to avoid cache line sharing issues when * driver is used with DMA-based SPI controllers (like atmel_spi) on * systems where main memory is not DMA-coherent (most non-x86 boards). */ struct ads7846_packet { u8 read_x, read_y, read_z1, read_z2, pwrdown; u16 dummy; /* for the pwrdown read */ struct ts_event tc; }; struct ads7846 { struct input_dev *input; char phys[32]; char name[32]; struct spi_device *spi; struct regulator *reg; #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE) struct attribute_group *attr_group; struct device *hwmon; #endif u16 model; u16 vref_mv; u16 vref_delay_usecs; u16 x_plate_ohms; u16 pressure_max; bool swap_xy; struct ads7846_packet *packet; struct spi_transfer xfer[18]; struct spi_message msg[5]; struct spi_message *last_msg; int msg_idx; int read_cnt; int read_rep; int last_read; u16 debounce_max; u16 debounce_tol; u16 debounce_rep; u16 penirq_recheck_delay_usecs; spinlock_t lock; struct hrtimer timer; unsigned pendown:1; /* P: lock */ unsigned pending:1; /* P: lock */ // FIXME remove "irq_disabled" unsigned irq_disabled:1; /* P: lock */ unsigned disabled:1; unsigned is_suspended:1; int (*filter)(void *data, int data_idx, int *val); void *filter_data; void (*filter_cleanup)(void *data); int (*get_pendown_state)(void); int gpio_pendown; void (*wait_for_sync)(void); }; /* leave chip selected when we're done, for quicker re-select? */ #if 0 #define CS_CHANGE(xfer) ((xfer).cs_change = 1) #else #define CS_CHANGE(xfer) ((xfer).cs_change = 0) #endif /*--------------------------------------------------------------------------*/ /* The ADS7846 has touchscreen and other sensors. * Earlier ads784x chips are somewhat compatible. */ #define ADS_START (1 << 7) #define ADS_A2A1A0_d_y (1 << 4) /* differential */ #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */ #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */ #define ADS_A2A1A0_d_x (5 << 4) /* differential */ #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */ #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */ #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */ #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */ #define ADS_8_BIT (1 << 3) #define ADS_12_BIT (0 << 3) #define ADS_SER (1 << 2) /* non-differential */ #define ADS_DFR (0 << 2) /* differential */ #define ADS_PD10_PDOWN (0 << 0) /* lowpower mode + penirq */ #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */ #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */ #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */ #define MAX_12BIT ((1<<12)-1) /* leave ADC powered up (disables penirq) between differential samples */ #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \ | ADS_12_BIT | ADS_DFR | \ (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0)) #define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref)) #define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref)) #define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref)) #define READ_X(vref) (READ_12BIT_DFR(x, 1, vref)) #define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */ /* single-ended samples need to first power up reference voltage; * we leave both ADC and VREF powered */ #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \ | ADS_12_BIT | ADS_SER) #define REF_ON (READ_12BIT_DFR(x, 1, 1)) #define REF_OFF (READ_12BIT_DFR(y, 0, 0)) /*--------------------------------------------------------------------------*/ /* * Non-touchscreen sensors only use single-ended conversions. * The range is GND..vREF. The ads7843 and ads7835 must use external vREF; * ads7846 lets that pin be unconnected, to use internal vREF. */ struct ser_req { u8 ref_on; u8 command; u8 ref_off; u16 scratch; __be16 sample; struct spi_message msg; struct spi_transfer xfer[6]; }; static void ads7846_enable(struct ads7846 *ts); static void ads7846_disable(struct ads7846 *ts); static int device_suspended(struct device *dev) { struct ads7846 *ts = dev_get_drvdata(dev); return ts->is_suspended || ts->disabled; } static int ads7846_read12_ser(struct device *dev, unsigned command) { struct spi_device *spi = to_spi_device(dev); struct ads7846 *ts = dev_get_drvdata(dev); struct ser_req *req = kzalloc(sizeof *req, GFP_KERNEL); int status; int use_internal; if (!req) return -ENOMEM; spi_message_init(&req->msg); /* FIXME boards with ads7846 might use external vref instead ... */ use_internal = (ts->model == 7846); /* maybe turn on internal vREF, and let it settle */ if (use_internal) { req->ref_on = REF_ON; req->xfer[0].tx_buf = &req->ref_on; req->xfer[0].len = 1; spi_message_add_tail(&req->xfer[0], &req->msg); req->xfer[1].rx_buf = &req->scratch; req->xfer[1].len = 2; /* for 1uF, settle for 800 usec; no cap, 100 usec. */ req->xfer[1].delay_usecs = ts->vref_delay_usecs; spi_message_add_tail(&req->xfer[1], &req->msg); } /* take sample */ req->command = (u8) command; req->xfer[2].tx_buf = &req->command; req->xfer[2].len = 1; spi_message_add_tail(&req->xfer[2], &req->msg); req->xfer[3].rx_buf = &req->sample; req->xfer[3].len = 2; spi_message_add_tail(&req->xfer[3], &req->msg); /* REVISIT: take a few more samples, and compare ... */ /* converter in low power mode & enable PENIRQ */ req->ref_off = PWRDOWN; req->xfer[4].tx_buf = &req->ref_off; req->xfer[4].len = 1; spi_message_add_tail(&req->xfer[4], &req->msg); req->xfer[5].rx_buf = &req->scratch; req->xfer[5].len = 2; CS_CHANGE(req->xfer[5]); spi_message_add_tail(&req->xfer[5], &req->msg); ts->irq_disabled = 1; disable_irq(spi->irq); status = spi_sync(spi, &req->msg); ts->irq_disabled = 0; enable_irq(spi->irq); if (status == 0) { /* on-wire is a must-ignore bit, a BE12 value, then padding */ status = be16_to_cpu(req->sample); status = status >> 3; status &= 0x0fff; } kfree(req); return status; } #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE) #define SHOW(name, var, adjust) static ssize_t \ name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \ { \ struct ads7846 *ts = dev_get_drvdata(dev); \ ssize_t v = ads7846_read12_ser(dev, \ READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \ if (v < 0) \ return v; \ return sprintf(buf, "%u\n", adjust(ts, v)); \ } \ static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL); /* Sysfs conventions report temperatures in millidegrees Celsius. * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high * accuracy scheme without calibration data. For now we won't try either; * userspace sees raw sensor values, and must scale/calibrate appropriately. */ static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v) { return v; } SHOW(temp0, temp0, null_adjust) /* temp1_input */ SHOW(temp1, temp1, null_adjust) /* temp2_input */ /* sysfs conventions report voltages in millivolts. We can convert voltages * if we know vREF. userspace may need to scale vAUX to match the board's * external resistors; we assume that vBATT only uses the internal ones. */ static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v) { unsigned retval = v; /* external resistors may scale vAUX into 0..vREF */ retval *= ts->vref_mv; retval = retval >> 12; return retval; } static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v) { unsigned retval = vaux_adjust(ts, v); /* ads7846 has a resistor ladder to scale this signal down */ if (ts->model == 7846) retval *= 4; return retval; } SHOW(in0_input, vaux, vaux_adjust) SHOW(in1_input, vbatt, vbatt_adjust) static struct attribute *ads7846_attributes[] = { &dev_attr_temp0.attr, &dev_attr_temp1.attr, &dev_attr_in0_input.attr, &dev_attr_in1_input.attr, NULL, }; static struct attribute_group ads7846_attr_group = { .attrs = ads7846_attributes, }; static struct attribute *ads7843_attributes[] = { &dev_attr_in0_input.attr, &dev_attr_in1_input.attr, NULL, }; static struct attribute_group ads7843_attr_group = { .attrs = ads7843_attributes, }; static struct attribute *ads7845_attributes[] = { &dev_attr_in0_input.attr, NULL, }; static struct attribute_group ads7845_attr_group = { .attrs = ads7845_attributes, }; static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts) { struct device *hwmon; int err; /* hwmon sensors need a reference voltage */ switch (ts->model) { case 7846: if (!ts->vref_mv) { dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n"); ts->vref_mv = 2500; } break; case 7845: case 7843: if (!ts->vref_mv) { dev_warn(&spi->dev, "external vREF for ADS%d not specified\n", ts->model); return 0; } break; } /* different chips have different sensor groups */ switch (ts->model) { case 7846: ts->attr_group = &ads7846_attr_group; break; case 7845: ts->attr_group = &ads7845_attr_group; break; case 7843: ts->attr_group = &ads7843_attr_group; break; default: dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model); return 0; } err = sysfs_create_group(&spi->dev.kobj, ts->attr_group); if (err) return err; hwmon = hwmon_device_register(&spi->dev); if (IS_ERR(hwmon)) { sysfs_remove_group(&spi->dev.kobj, ts->attr_group); return PTR_ERR(hwmon); } ts->hwmon = hwmon; return 0; } static void ads784x_hwmon_unregister(struct spi_device *spi, struct ads7846 *ts) { if (ts->hwmon) { sysfs_remove_group(&spi->dev.kobj, ts->attr_group); hwmon_device_unregister(ts->hwmon); } } #else static inline int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts) { return 0; } static inline void ads784x_hwmon_unregister(struct spi_device *spi, struct ads7846 *ts) { } #endif static int is_pen_down(struct device *dev) { struct ads7846 *ts = dev_get_drvdata(dev); return ts->pendown; } static ssize_t ads7846_pen_down_show(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "%u\n", is_pen_down(dev)); } static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL); static ssize_t ads7846_disable_show(struct device *dev, struct device_attribute *attr, char *buf) { struct ads7846 *ts = dev_get_drvdata(dev); return sprintf(buf, "%u\n", ts->disabled); } static ssize_t ads7846_disable_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct ads7846 *ts = dev_get_drvdata(dev); unsigned long i; if (strict_strtoul(buf, 10, &i)) return -EINVAL; spin_lock_irq(&ts->lock); if (i) ads7846_disable(ts); else ads7846_enable(ts); spin_unlock_irq(&ts->lock); return count; } static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store); static struct attribute *ads784x_attributes[] = { &dev_attr_pen_down.attr, &dev_attr_disable.attr, NULL, }; static struct attribute_group ads784x_attr_group = { .attrs = ads784x_attributes, }; /*--------------------------------------------------------------------------*/ static int get_pendown_state(struct ads7846 *ts) { if (ts->get_pendown_state) return ts->get_pendown_state(); return !gpio_get_value(ts->gpio_pendown); } static void null_wait_for_sync(void) { } /* * PENIRQ only kicks the timer. The timer only reissues the SPI transfer, * to retrieve touchscreen status. * * The SPI transfer completion callback does the real work. It reports * touchscreen events and reactivates the timer (or IRQ) as appropriate. */ static void ads7846_rx(void *ads) { struct ads7846 *ts = ads; struct ads7846_packet *packet = ts->packet; unsigned Rt; u16 x, y, z1, z2; /* ads7846_rx_val() did in-place conversion (including byteswap) from * on-the-wire format as part of debouncing to get stable readings. */ x = packet->tc.x; y = packet->tc.y; z1 = packet->tc.z1; z2 = packet->tc.z2; /* range filtering */ if (x == MAX_12BIT) x = 0; if (ts->model == 7843) { Rt = ts->pressure_max / 2; } else if (likely(x && z1)) { /* compute touch pressure resistance using equation #2 */ Rt = z2; Rt -= z1; Rt *= x; Rt *= ts->x_plate_ohms; Rt /= z1; Rt = (Rt + 2047) >> 12; } else { Rt = 0; } /* Sample found inconsistent by debouncing or pressure is beyond * the maximum. Don't report it to user space, repeat at least * once more the measurement */ if (packet->tc.ignore || Rt > ts->pressure_max) { dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n", packet->tc.ignore, Rt); hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD), HRTIMER_MODE_REL); return; } /* Maybe check the pendown state before reporting. This discards * false readings when the pen is lifted. */ if (ts->penirq_recheck_delay_usecs) { udelay(ts->penirq_recheck_delay_usecs); if (!get_pendown_state(ts)) Rt = 0; } /* NOTE: We can't rely on the pressure to determine the pen down * state, even this controller has a pressure sensor. The pressure * value can fluctuate for quite a while after lifting the pen and * in some cases may not even settle at the expected value. * * The only safe way to check for the pen up condition is in the * timer by reading the pen signal state (it's a GPIO _and_ IRQ). */ if (Rt) { struct input_dev *input = ts->input; if (!ts->pendown) { input_report_key(input, BTN_TOUCH, 1); ts->pendown = 1; dev_vdbg(&ts->spi->dev, "DOWN\n"); } if (ts->swap_xy) swap(x, y); input_report_abs(input, ABS_X, x); input_report_abs(input, ABS_Y, y); input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt); input_sync(input); dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt); } hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD), HRTIMER_MODE_REL); } static int ads7846_debounce(void *ads, int data_idx, int *val) { struct ads7846 *ts = ads; if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) { /* Start over collecting consistent readings. */ ts->read_rep = 0; /* Repeat it, if this was the first read or the read * wasn't consistent enough. */ if (ts->read_cnt < ts->debounce_max) { ts->last_read = *val; ts->read_cnt++; return ADS7846_FILTER_REPEAT; } else { /* Maximum number of debouncing reached and still * not enough number of consistent readings. Abort * the whole sample, repeat it in the next sampling * period. */ ts->read_cnt = 0; return ADS7846_FILTER_IGNORE; } } else { if (++ts->read_rep > ts->debounce_rep) { /* Got a good reading for this coordinate, * go for the next one. */ ts->read_cnt = 0; ts->read_rep = 0; return ADS7846_FILTER_OK; } else { /* Read more values that are consistent. */ ts->read_cnt++; return ADS7846_FILTER_REPEAT; } } } static int ads7846_no_filter(void *ads, int data_idx, int *val) { return ADS7846_FILTER_OK; } static void ads7846_rx_val(void *ads) { struct ads7846 *ts = ads; struct ads7846_packet *packet = ts->packet; struct spi_message *m; struct spi_transfer *t; int val; int action; int status; m = &ts->msg[ts->msg_idx]; t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list); /* adjust: on-wire is a must-ignore bit, a BE12 value, then padding; * built from two 8 bit values written msb-first. */ val = be16_to_cpup((__be16 *)t->rx_buf) >> 3; action = ts->filter(ts->filter_data, ts->msg_idx, &val); switch (action) { case ADS7846_FILTER_REPEAT: break; case ADS7846_FILTER_IGNORE: packet->tc.ignore = 1; /* Last message will contain ads7846_rx() as the * completion function. */ m = ts->last_msg; break; case ADS7846_FILTER_OK: *(u16 *)t->rx_buf = val; packet->tc.ignore = 0; m = &ts->msg[++ts->msg_idx]; break; default: BUG(); } ts->wait_for_sync(); status = spi_async(ts->spi, m); if (status) dev_err(&ts->spi->dev, "spi_async --> %d\n", status); } static enum hrtimer_restart ads7846_timer(struct hrtimer *handle) { struct ads7846 *ts = container_of(handle, struct ads7846, timer); int status = 0; spin_lock(&ts->lock); if (unlikely(!get_pendown_state(ts) || device_suspended(&ts->spi->dev))) { if (ts->pendown) { struct input_dev *input = ts->input; input_report_key(input, BTN_TOUCH, 0); input_report_abs(input, ABS_PRESSURE, 0); input_sync(input); ts->pendown = 0; dev_vdbg(&ts->spi->dev, "UP\n"); } /* measurement cycle ended */ if (!device_suspended(&ts->spi->dev)) { ts->irq_disabled = 0; enable_irq(ts->spi->irq); } ts->pending = 0; } else { /* pen is still down, continue with the measurement */ ts->msg_idx = 0; ts->wait_for_sync(); status = spi_async(ts->spi, &ts->msg[0]); if (status) dev_err(&ts->spi->dev, "spi_async --> %d\n", status); } spin_unlock(&ts->lock); return HRTIMER_NORESTART; } static irqreturn_t ads7846_irq(int irq, void *handle) { struct ads7846 *ts = handle; unsigned long flags; spin_lock_irqsave(&ts->lock, flags); if (likely(get_pendown_state(ts))) { if (!ts->irq_disabled) { /* The ARM do_simple_IRQ() dispatcher doesn't act * like the other dispatchers: it will report IRQs * even after they've been disabled. We work around * that here. (The "generic irq" framework may help...) */ ts->irq_disabled = 1; disable_irq_nosync(ts->spi->irq); ts->pending = 1; hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY), HRTIMER_MODE_REL); } } spin_unlock_irqrestore(&ts->lock, flags); return IRQ_HANDLED; } /*--------------------------------------------------------------------------*/ /* Must be called with ts->lock held */ static void ads7846_disable(struct ads7846 *ts) { if (ts->disabled) return; ts->disabled = 1; /* are we waiting for IRQ, or polling? */ if (!ts->pending) { ts->irq_disabled = 1; disable_irq(ts->spi->irq); } else { /* the timer will run at least once more, and * leave everything in a clean state, IRQ disabled */ while (ts->pending) { spin_unlock_irq(&ts->lock); msleep(1); spin_lock_irq(&ts->lock); } } regulator_disable(ts->reg); /* we know the chip's in lowpower mode since we always * leave it that way after every request */ } /* Must be called with ts->lock held */ static void ads7846_enable(struct ads7846 *ts) { if (!ts->disabled) return; regulator_enable(ts->reg); ts->disabled = 0; ts->irq_disabled = 0; enable_irq(ts->spi->irq); } static int ads7846_suspend(struct spi_device *spi, pm_message_t message) { struct ads7846 *ts = dev_get_drvdata(&spi->dev); spin_lock_irq(&ts->lock); ts->is_suspended = 1; ads7846_disable(ts); spin_unlock_irq(&ts->lock); return 0; } static int ads7846_resume(struct spi_device *spi) { struct ads7846 *ts = dev_get_drvdata(&spi->dev); spin_lock_irq(&ts->lock); ts->is_suspended = 0; ads7846_enable(ts); spin_unlock_irq(&ts->lock); return 0; } static int __devinit setup_pendown(struct spi_device *spi, struct ads7846 *ts) { struct ads7846_platform_data *pdata = spi->dev.platform_data; int err; /* REVISIT when the irq can be triggered active-low, or if for some * reason the touchscreen isn't hooked up, we don't need to access * the pendown state. */ if (!pdata->get_pendown_state && !gpio_is_valid(pdata->gpio_pendown)) { dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n"); return -EINVAL; } if (pdata->get_pendown_state) { ts->get_pendown_state = pdata->get_pendown_state; return 0; } err = gpio_request(pdata->gpio_pendown, "ads7846_pendown"); if (err) { dev_err(&spi->dev, "failed to request pendown GPIO%d\n", pdata->gpio_pendown); return err; } ts->gpio_pendown = pdata->gpio_pendown; return 0; } static int __devinit ads7846_probe(struct spi_device *spi) { struct ads7846 *ts; struct ads7846_packet *packet; struct input_dev *input_dev; struct ads7846_platform_data *pdata = spi->dev.platform_data; struct spi_message *m; struct spi_transfer *x; int vref; int err; if (!spi->irq) { dev_dbg(&spi->dev, "no IRQ?\n"); return -ENODEV; } if (!pdata) { dev_dbg(&spi->dev, "no platform data?\n"); return -ENODEV; } /* don't exceed max specified sample rate */ if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) { dev_dbg(&spi->dev, "f(sample) %d KHz?\n", (spi->max_speed_hz/SAMPLE_BITS)/1000); return -EINVAL; } /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except * that even if the hardware can do that, the SPI controller driver * may not. So we stick to very-portable 8 bit words, both RX and TX. */ spi->bits_per_word = 8; spi->mode = SPI_MODE_0; err = spi_setup(spi); if (err < 0) return err; ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL); packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL); input_dev = input_allocate_device(); if (!ts || !packet || !input_dev) { err = -ENOMEM; goto err_free_mem; } dev_set_drvdata(&spi->dev, ts); ts->packet = packet; ts->spi = spi; ts->input = input_dev; ts->vref_mv = pdata->vref_mv; ts->swap_xy = pdata->swap_xy; hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); ts->timer.function = ads7846_timer; spin_lock_init(&ts->lock); ts->model = pdata->model ? : 7846; ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100; ts->x_plate_ohms = pdata->x_plate_ohms ? : 400; ts->pressure_max = pdata->pressure_max ? : ~0; if (pdata->filter != NULL) { if (pdata->filter_init != NULL) { err = pdata->filter_init(pdata, &ts->filter_data); if (err < 0) goto err_free_mem; } ts->filter = pdata->filter; ts->filter_cleanup = pdata->filter_cleanup; } else if (pdata->debounce_max) { ts->debounce_max = pdata->debounce_max; if (ts->debounce_max < 2) ts->debounce_max = 2; ts->debounce_tol = pdata->debounce_tol; ts->debounce_rep = pdata->debounce_rep; ts->filter = ads7846_debounce; ts->filter_data = ts; } else ts->filter = ads7846_no_filter; err = setup_pendown(spi, ts); if (err) goto err_cleanup_filter; if (pdata->penirq_recheck_delay_usecs) ts->penirq_recheck_delay_usecs = pdata->penirq_recheck_delay_usecs; ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync; snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev)); snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model); input_dev->name = ts->name; input_dev->phys = ts->phys; input_dev->dev.parent = &spi->dev; input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH); input_set_abs_params(input_dev, ABS_X, pdata->x_min ? : 0, pdata->x_max ? : MAX_12BIT, 0, 0); input_set_abs_params(input_dev, ABS_Y, pdata->y_min ? : 0, pdata->y_max ? : MAX_12BIT, 0, 0); input_set_abs_params(input_dev, ABS_PRESSURE, pdata->pressure_min, pdata->pressure_max, 0, 0); vref = pdata->keep_vref_on; if (ts->model == 7873) { /* The AD7873 is almost identical to the ADS7846 * keep VREF off during differential/ratiometric * conversion modes */ ts->model = 7846; vref = 0; } /* set up the transfers to read touchscreen state; this assumes we * use formula #2 for pressure, not #3. */ m = &ts->msg[0]; x = ts->xfer; spi_message_init(m); /* y- still on; turn on only y+ (and ADC) */ packet->read_y = READ_Y(vref); x->tx_buf = &packet->read_y; x->len = 1; spi_message_add_tail(x, m); x++; x->rx_buf = &packet->tc.y; x->len = 2; spi_message_add_tail(x, m); /* the first sample after switching drivers can be low quality; * optionally discard it, using a second one after the signals * have had enough time to stabilize. */ if (pdata->settle_delay_usecs) { x->delay_usecs = pdata->settle_delay_usecs; x++; x->tx_buf = &packet->read_y; x->len = 1; spi_message_add_tail(x, m); x++; x->rx_buf = &packet->tc.y; x->len = 2; spi_message_add_tail(x, m); } m->complete = ads7846_rx_val; m->context = ts; m++; spi_message_init(m); /* turn y- off, x+ on, then leave in lowpower */ x++; packet->read_x = READ_X(vref); x->tx_buf = &packet->read_x; x->len = 1; spi_message_add_tail(x, m); x++; x->rx_buf = &packet->tc.x; x->len = 2; spi_message_add_tail(x, m); /* ... maybe discard first sample ... */ if (pdata->settle_delay_usecs) { x->delay_usecs = pdata->settle_delay_usecs; x++; x->tx_buf = &packet->read_x; x->len = 1; spi_message_add_tail(x, m); x++; x->rx_buf = &packet->tc.x; x->len = 2; spi_message_add_tail(x, m); } m->complete = ads7846_rx_val; m->context = ts; /* turn y+ off, x- on; we'll use formula #2 */ if (ts->model == 7846) { m++; spi_message_init(m); x++; packet->read_z1 = READ_Z1(vref); x->tx_buf = &packet->read_z1; x->len = 1; spi_message_add_tail(x, m); x++; x->rx_buf = &packet->tc.z1; x->len = 2; spi_message_add_tail(x, m); /* ... maybe discard first sample ... */ if (pdata->settle_delay_usecs) { x->delay_usecs = pdata->settle_delay_usecs; x++; x->tx_buf = &packet->read_z1; x->len = 1; spi_message_add_tail(x, m); x++; x->rx_buf = &packet->tc.z1; x->len = 2; spi_message_add_tail(x, m); } m->complete = ads7846_rx_val; m->context = ts; m++; spi_message_init(m); x++; packet->read_z2 = READ_Z2(vref); x->tx_buf = &packet->read_z2; x->len = 1; spi_message_add_tail(x, m); x++; x->rx_buf = &packet->tc.z2; x->len = 2; spi_message_add_tail(x, m); /* ... maybe discard first sample ... */ if (pdata->settle_delay_usecs) { x->delay_usecs = pdata->settle_delay_usecs; x++; x->tx_buf = &packet->read_z2; x->len = 1; spi_message_add_tail(x, m); x++; x->rx_buf = &packet->tc.z2; x->len = 2; spi_message_add_tail(x, m); } m->complete = ads7846_rx_val; m->context = ts; } /* power down */ m++; spi_message_init(m); x++; packet->pwrdown = PWRDOWN; x->tx_buf = &packet->pwrdown; x->len = 1; spi_message_add_tail(x, m); x++; x->rx_buf = &packet->dummy; x->len = 2; CS_CHANGE(*x); spi_message_add_tail(x, m); m->complete = ads7846_rx; m->context = ts; ts->last_msg = m; ts->reg = regulator_get(&spi->dev, "vcc"); if (IS_ERR(ts->reg)) { dev_err(&spi->dev, "unable to get regulator: %ld\n", PTR_ERR(ts->reg)); goto err_free_gpio; } err = regulator_enable(ts->reg); if (err) { dev_err(&spi->dev, "unable to enable regulator: %d\n", err); goto err_put_regulator; } if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING, spi->dev.driver->name, ts)) { dev_info(&spi->dev, "trying pin change workaround on irq %d\n", spi->irq); err = request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING, spi->dev.driver->name, ts); if (err) { dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq); goto err_disable_regulator; } } err = ads784x_hwmon_register(spi, ts); if (err) goto err_free_irq; dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq); /* take a first sample, leaving nPENIRQ active and vREF off; avoid * the touchscreen, in case it's not connected. */ (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON); err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group); if (err) goto err_remove_hwmon; err = input_register_device(input_dev); if (err) goto err_remove_attr_group; return 0; err_remove_attr_group: sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group); err_remove_hwmon: ads784x_hwmon_unregister(spi, ts); err_free_irq: free_irq(spi->irq, ts); err_disable_regulator: regulator_disable(ts->reg); err_put_regulator: regulator_put(ts->reg); err_free_gpio: if (ts->gpio_pendown != -1) gpio_free(ts->gpio_pendown); err_cleanup_filter: if (ts->filter_cleanup) ts->filter_cleanup(ts->filter_data); err_free_mem: input_free_device(input_dev); kfree(packet); kfree(ts); return err; } static int __devexit ads7846_remove(struct spi_device *spi) { struct ads7846 *ts = dev_get_drvdata(&spi->dev); ads784x_hwmon_unregister(spi, ts); input_unregister_device(ts->input); ads7846_suspend(spi, PMSG_SUSPEND); sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group); free_irq(ts->spi->irq, ts); /* suspend left the IRQ disabled */ enable_irq(ts->spi->irq); regulator_disable(ts->reg); regulator_put(ts->reg); if (ts->gpio_pendown != -1) gpio_free(ts->gpio_pendown); if (ts->filter_cleanup) ts->filter_cleanup(ts->filter_data); kfree(ts->packet); kfree(ts); dev_dbg(&spi->dev, "unregistered touchscreen\n"); return 0; } static struct spi_driver ads7846_driver = { .driver = { .name = "ads7846", .bus = &spi_bus_type, .owner = THIS_MODULE, }, .probe = ads7846_probe, .remove = __devexit_p(ads7846_remove), .suspend = ads7846_suspend, .resume = ads7846_resume, }; static int __init ads7846_init(void) { return spi_register_driver(&ads7846_driver); } module_init(ads7846_init); static void __exit ads7846_exit(void) { spi_unregister_driver(&ads7846_driver); } module_exit(ads7846_exit); MODULE_DESCRIPTION("ADS7846 TouchScreen Driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS("spi:ads7846");