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OpenCloudOS-Kernel/drivers/input/touchscreen/ads7846.c

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/*
* 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(&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(&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");
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