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linux-next/drivers/input/touchscreen/ads7846.c
Kevin Hilman 067fb2f648 Input: ads7846 - return error on regulator_get() failure
In probe(), if regulator_get() failed, an error code was not being
returned causing the driver to be successfully bound, even though
probe failed.  This in turn caused the suspend, resume and remove
methods to be registered and accessed via the SPI core.  Since these
functions all access private driver data using pointers that had been
freed during the failed probe, this would lead to unpredictable
behavior.

This patch ensures that probe() returns an error code in this failure
case so the driver is not bound.

Found using lockdep and noticing the lock used in the suspend/resum
path pointed to a bogus lock due to the freed memory.

Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2010-05-26 23:34:56 -07:00

1297 lines
31 KiB
C

/*
* 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 <linux/regulator/consumer.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, 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);
if (device_may_wakeup(&ts->spi->dev))
enable_irq_wake(ts->spi->irq);
return 0;
}
static int ads7846_resume(struct spi_device *spi)
{
struct ads7846 *ts = dev_get_drvdata(&spi->dev);
if (device_may_wakeup(&ts->spi->dev))
disable_irq_wake(ts->spi->irq);
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)) {
err = PTR_ERR(ts->reg);
dev_err(&spi->dev, "unable to get regulator: %ld\n", err);
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;
device_init_wakeup(&spi->dev, pdata->wakeup);
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);
device_init_wakeup(&spi->dev, false);
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");