diff options
Diffstat (limited to 'drivers/input/touchscreen/ads7846.c')
| -rw-r--r-- | drivers/input/touchscreen/ads7846.c | 1233 |
1 files changed, 1233 insertions, 0 deletions
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c new file mode 100644 index 0000000..b9b7fc6 --- /dev/null +++ b/drivers/input/touchscreen/ads7846.c @@ -0,0 +1,1233 @@ +/* + * ADS7846 based touchscreen and sensor driver + * + * Copyright (c) 2005 David Brownell + * Copyright (c) 2006 Nokia Corporation + * Various changes: Imre Deak <imre.deak@nokia.com> + * + * 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 <linux/hwmon.h> +#include <linux/init.h> +#include <linux/err.h> +#include <linux/delay.h> +#include <linux/input.h> +#include <linux/interrupt.h> +#include <linux/slab.h> +#include <linux/gpio.h> +#include <linux/spi/spi.h> +#include <linux/spi/ads7846.h> +#include <asm/irq.h> + + +/* + * This code has been heavily tested on a Nokia 770, and lightly + * tested on other ads7846 devices (OSK/Mistral, Lubbock). + * TSC2046 is just newer ads7846 silicon. + * Support for ads7843 tested on Atmel at91sam926x-EK. + * Support for ads7845 has only been stubbed in. + * + * 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]; + + struct spi_device *spi; + +#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; + + 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; +}; + +/* 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 Celcius. + * 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); + 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); +} + +/* + * 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) { +#ifdef VERBOSE + pr_debug("%s: ignored %d pressure %d\n", + ts->spi->dev.bus_id, packet->tc.ignore, Rt); +#endif + 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; +#ifdef VERBOSE + dev_dbg(&ts->spi->dev, "DOWN\n"); +#endif + } + input_report_abs(input, ABS_X, x); + input_report_abs(input, ABS_Y, y); + input_report_abs(input, ABS_PRESSURE, Rt); + + input_sync(input); +#ifdef VERBOSE + dev_dbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt); +#endif + } + + 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(); + } + 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_irq(&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; +#ifdef VERBOSE + dev_dbg(&ts->spi->dev, "UP\n"); +#endif + } + + /* 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; + status = spi_async(ts->spi, &ts->msg[0]); + if (status) + dev_err(&ts->spi->dev, "spi_async --> %d\n", status); + } + + spin_unlock_irq(&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(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); + } + } + + /* 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; + + 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; + + 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; + + snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id); + + input_dev->name = "ADS784x Touchscreen"; + 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; + + /* 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; + + if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING, + spi->dev.driver->name, ts)) { + dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq); + err = -EBUSY; + goto err_free_gpio; + } + + 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_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); + + 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"); |
