cregit-Linux how code gets into the kernel

Release 4.11 drivers/input/touchscreen/ad7877.c

Directory: drivers/input/touchscreen
/*
 * Copyright (C) 2006-2008 Michael Hennerich, Analog Devices Inc.
 *
 * Description: AD7877 based touchscreen, sensor (ADCs), DAC and GPIO driver
 * Based on:    ads7846.c
 *
 * Bugs:        Enter bugs at http://blackfin.uclinux.org/
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see the file COPYING, or write
 * to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * History:
 * 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
 */


#include <linux/device.h>
#include <linux/delay.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/pm.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/spi/ad7877.h>
#include <linux/module.h>
#include <asm/irq.h>


#define	TS_PEN_UP_TIMEOUT	msecs_to_jiffies(100)


#define MAX_SPI_FREQ_HZ			20000000

#define	MAX_12BIT			((1<<12)-1)


#define AD7877_REG_ZEROS			0

#define AD7877_REG_CTRL1			1

#define AD7877_REG_CTRL2			2

#define AD7877_REG_ALERT			3

#define AD7877_REG_AUX1HIGH			4

#define AD7877_REG_AUX1LOW			5

#define AD7877_REG_BAT1HIGH			6

#define AD7877_REG_BAT1LOW			7

#define AD7877_REG_BAT2HIGH			8

#define AD7877_REG_BAT2LOW			9

#define AD7877_REG_TEMP1HIGH			10

#define AD7877_REG_TEMP1LOW			11

#define AD7877_REG_SEQ0				12

#define AD7877_REG_SEQ1				13

#define AD7877_REG_DAC				14

#define AD7877_REG_NONE1			15

#define AD7877_REG_EXTWRITE			15

#define AD7877_REG_XPLUS			16

#define AD7877_REG_YPLUS			17

#define AD7877_REG_Z2				18

#define AD7877_REG_aux1				19

#define AD7877_REG_aux2				20

#define AD7877_REG_aux3				21

#define AD7877_REG_bat1				22

#define AD7877_REG_bat2				23

#define AD7877_REG_temp1			24

#define AD7877_REG_temp2			25

#define AD7877_REG_Z1				26

#define AD7877_REG_GPIOCTRL1			27

#define AD7877_REG_GPIOCTRL2			28

#define AD7877_REG_GPIODATA			29

#define AD7877_REG_NONE2			30

#define AD7877_REG_NONE3			31


#define AD7877_SEQ_YPLUS_BIT			(1<<11)

#define AD7877_SEQ_XPLUS_BIT			(1<<10)

#define AD7877_SEQ_Z2_BIT			(1<<9)

#define AD7877_SEQ_AUX1_BIT			(1<<8)

#define AD7877_SEQ_AUX2_BIT			(1<<7)

#define AD7877_SEQ_AUX3_BIT			(1<<6)

#define AD7877_SEQ_BAT1_BIT			(1<<5)

#define AD7877_SEQ_BAT2_BIT			(1<<4)

#define AD7877_SEQ_TEMP1_BIT			(1<<3)

#define AD7877_SEQ_TEMP2_BIT			(1<<2)

#define AD7877_SEQ_Z1_BIT			(1<<1)

enum {
	
AD7877_SEQ_YPOS  = 0,
	
AD7877_SEQ_XPOS  = 1,
	
AD7877_SEQ_Z2    = 2,
	
AD7877_SEQ_AUX1  = 3,
	
AD7877_SEQ_AUX2  = 4,
	
AD7877_SEQ_AUX3  = 5,
	
AD7877_SEQ_BAT1  = 6,
	
AD7877_SEQ_BAT2  = 7,
	
AD7877_SEQ_TEMP1 = 8,
	
AD7877_SEQ_TEMP2 = 9,
	
AD7877_SEQ_Z1    = 10,
	
AD7877_NR_SENSE  = 11,
};

/* DAC Register Default RANGE 0 to Vcc, Volatge Mode, DAC On */

#define AD7877_DAC_CONF			0x1

/* If gpio3 is set AUX3/GPIO3 acts as GPIO Output */

#define AD7877_EXTW_GPIO_3_CONF		0x1C4

#define AD7877_EXTW_GPIO_DATA		0x200

/* Control REG 2 */

#define AD7877_TMR(x)			((x & 0x3) << 0)

#define AD7877_REF(x)			((x & 0x1) << 2)

#define AD7877_POL(x)			((x & 0x1) << 3)

#define AD7877_FCD(x)			((x & 0x3) << 4)

#define AD7877_PM(x)			((x & 0x3) << 6)

#define AD7877_ACQ(x)			((x & 0x3) << 8)

#define AD7877_AVG(x)			((x & 0x3) << 10)

/* Control REG 1 */

#define	AD7877_SER			(1 << 11)	
/* non-differential */

#define	AD7877_DFR			(0 << 11)	
/* differential */


#define AD7877_MODE_NOC  (0)	
/* Do not convert */

#define AD7877_MODE_SCC  (1)	
/* Single channel conversion */

#define AD7877_MODE_SEQ0 (2)	
/* Sequence 0 in Slave Mode */

#define AD7877_MODE_SEQ1 (3)	
/* Sequence 1 in Master Mode */


#define AD7877_CHANADD(x)		((x&0xF)<<7)

#define AD7877_READADD(x)		((x)<<2)

#define AD7877_WRITEADD(x)		((x)<<12)


#define AD7877_READ_CHAN(x) (AD7877_WRITEADD(AD7877_REG_CTRL1) | AD7877_SER | \
                AD7877_MODE_SCC | AD7877_CHANADD(AD7877_REG_ ## x) | \
                AD7877_READADD(AD7877_REG_ ## x))


#define AD7877_MM_SEQUENCE (AD7877_SEQ_YPLUS_BIT | AD7877_SEQ_XPLUS_BIT | \
                AD7877_SEQ_Z2_BIT | AD7877_SEQ_Z1_BIT)

/*
 * Non-touchscreen sensors only use single-ended conversions.
 */


struct ser_req {
	
u16			reset;
	
u16			ref_on;
	
u16			command;
	
struct spi_message	msg;
	
struct spi_transfer	xfer[6];

	/*
         * DMA (thus cache coherency maintenance) requires the
         * transfer buffers to live in their own cache lines.
         */
	
u16 sample ____cacheline_aligned;
};


struct ad7877 {
	
struct input_dev	*input;
	
char			phys[32];

	
struct spi_device	*spi;
	
u16			model;
	
u16			vref_delay_usecs;
	
u16			x_plate_ohms;
	
u16			pressure_max;

	
u16			cmd_crtl1;
	
u16			cmd_crtl2;
	
u16			cmd_dummy;
	
u16			dac;

	
u8			stopacq_polarity;
	
u8			first_conversion_delay;
	
u8			acquisition_time;
	
u8			averaging;
	
u8			pen_down_acc_interval;

	
struct spi_transfer	xfer[AD7877_NR_SENSE + 2];
	
struct spi_message	msg;

	
struct mutex		mutex;
	
bool			disabled;	/* P: mutex */
	
bool			gpio3;		/* P: mutex */
	
bool			gpio4;		/* P: mutex */

	
spinlock_t		lock;
	
struct timer_list	timer;		/* P: lock */

	/*
         * DMA (thus cache coherency maintenance) requires the
         * transfer buffers to live in their own cache lines.
         */
	
u16 conversion_data[AD7877_NR_SENSE] ____cacheline_aligned;
};


static bool gpio3;
module_param(gpio3, bool, 0);
MODULE_PARM_DESC(gpio3, "If gpio3 is set to 1 AUX3 acts as GPIO3");




static int ad7877_read(struct spi_device *spi, u16 reg)
{
	struct ser_req *req;
	int status, ret;

	req = kzalloc(sizeof *req, GFP_KERNEL);
	if (!req)
		return -ENOMEM;

	spi_message_init(&req->msg);

	req->command = (u16) (AD7877_WRITEADD(AD7877_REG_CTRL1) |
			AD7877_READADD(reg));
	req->xfer[0].tx_buf = &req->command;
	req->xfer[0].len = 2;
	req->xfer[0].cs_change = 1;

	req->xfer[1].rx_buf = &req->sample;
	req->xfer[1].len = 2;

	spi_message_add_tail(&req->xfer[0], &req->msg);
	spi_message_add_tail(&req->xfer[1], &req->msg);

	status = spi_sync(spi, &req->msg);
	ret = status ? : req->sample;

	kfree(req);

	return ret;
}


Contributors
PersonTokensPropCommitsCommitProp
Michael Hennerich193100.00%2100.00%


Total193100.00%2100.00%






static int ad7877_write(struct spi_device *spi, u16 reg, u16 val)
{
	struct ser_req *req;
	int status;

	req = kzalloc(sizeof *req, GFP_KERNEL);
	if (!req)
		return -ENOMEM;

	spi_message_init(&req->msg);

	req->command = (u16) (AD7877_WRITEADD(reg) | (val & MAX_12BIT));
	req->xfer[0].tx_buf = &req->command;
	req->xfer[0].len = 2;

	spi_message_add_tail(&req->xfer[0], &req->msg);

	status = spi_sync(spi, &req->msg);

	kfree(req);

	return status;
}


Contributors
PersonTokensPropCommitsCommitProp
Michael Hennerich134100.00%1100.00%


Total134100.00%1100.00%






static int ad7877_read_adc(struct spi_device *spi, unsigned command)
{
	struct ad7877 *ts = spi_get_drvdata(spi);
	struct ser_req *req;
	int status;
	int sample;
	int i;

	req = kzalloc(sizeof *req, GFP_KERNEL);
	if (!req)
		return -ENOMEM;

	spi_message_init(&req->msg);

	/* activate reference, so it has time to settle; */
	req->ref_on = AD7877_WRITEADD(AD7877_REG_CTRL2) |
			 AD7877_POL(ts->stopacq_polarity) |
			 AD7877_AVG(0) | AD7877_PM(2) | AD7877_TMR(0) |
			 AD7877_ACQ(ts->acquisition_time) | AD7877_FCD(0);

	req->reset = AD7877_WRITEADD(AD7877_REG_CTRL1) | AD7877_MODE_NOC;

	req->command = (u16) command;

	req->xfer[0].tx_buf = &req->reset;
	req->xfer[0].len = 2;
	req->xfer[0].cs_change = 1;

	req->xfer[1].tx_buf = &req->ref_on;
	req->xfer[1].len = 2;
	req->xfer[1].delay_usecs = ts->vref_delay_usecs;
	req->xfer[1].cs_change = 1;

	req->xfer[2].tx_buf = &req->command;
	req->xfer[2].len = 2;
	req->xfer[2].delay_usecs = ts->vref_delay_usecs;
	req->xfer[2].cs_change = 1;

	req->xfer[3].rx_buf = &req->sample;
	req->xfer[3].len = 2;
	req->xfer[3].cs_change = 1;

	req->xfer[4].tx_buf = &ts->cmd_crtl2;	/*REF OFF*/
	req->xfer[4].len = 2;
	req->xfer[4].cs_change = 1;

	req->xfer[5].tx_buf = &ts->cmd_crtl1;	/*DEFAULT*/
	req->xfer[5].len = 2;

	/* group all the transfers together, so we can't interfere with
         * reading touchscreen state; disable penirq while sampling
         */
	for (i = 0; i < 6; i++)
		spi_message_add_tail(&req->xfer[i], &req->msg);

	status = spi_sync(spi, &req->msg);
	sample = req->sample;

	kfree(req);

	return status ? : sample;
}


Contributors
PersonTokensPropCommitsCommitProp
Michael Hennerich42199.76%266.67%


Jingoo Han10.24%133.33%


Total422100.00%3100.00%






static int ad7877_process_data(struct ad7877 *ts)
{
	struct input_dev *input_dev = ts->input;
	unsigned Rt;
	u16 x, y, z1, z2;

	x = ts->conversion_data[AD7877_SEQ_XPOS] & MAX_12BIT;
	y = ts->conversion_data[AD7877_SEQ_YPOS] & MAX_12BIT;
	z1 = ts->conversion_data[AD7877_SEQ_Z1] & MAX_12BIT;
	z2 = ts->conversion_data[AD7877_SEQ_Z2] & MAX_12BIT;

	/*
         * The samples processed here are already preprocessed by the AD7877.
         * The preprocessing function consists of an averaging filter.
         * The combination of 'first conversion delay' and averaging provides a robust solution,
         * discarding the spurious noise in the signal and keeping only the data of interest.
         * The size of the averaging filter is programmable. (dev.platform_data, see linux/spi/ad7877.h)
         * Other user-programmable conversion controls include variable acquisition time,
         * and first conversion delay. Up to 16 averages can be taken per conversion.
         */

	if (likely(x && z1)) {
		/* compute touch pressure resistance using equation #1 */
		Rt = (z2 - z1) * x * ts->x_plate_ohms;
		Rt /= z1;
		Rt = (Rt + 2047) >> 12;

		/*
                 * Sample found inconsistent, pressure is beyond
                 * the maximum. Don't report it to user space.
                 */
		if (Rt > ts->pressure_max)
			return -EINVAL;

		if (!timer_pending(&ts->timer))
			input_report_key(input_dev, BTN_TOUCH, 1);

		input_report_abs(input_dev, ABS_X, x);
		input_report_abs(input_dev, ABS_Y, y);
		input_report_abs(input_dev, ABS_PRESSURE, Rt);
		input_sync(input_dev);

		return 0;
	}

	return -EINVAL;
}


Contributors
PersonTokensPropCommitsCommitProp
Michael Hennerich18899.47%375.00%


Dmitry Torokhov10.53%125.00%


Total189100.00%4100.00%






static inline void ad7877_ts_event_release(struct ad7877 *ts)
{
	struct input_dev *input_dev = ts->input;

	input_report_abs(input_dev, ABS_PRESSURE, 0);
	input_report_key(input_dev, BTN_TOUCH, 0);
	input_sync(input_dev);
}


Contributors
PersonTokensPropCommitsCommitProp
Michael Hennerich44100.00%2100.00%


Total44100.00%2100.00%






static void ad7877_timer(unsigned long handle)
{
	struct ad7877 *ts = (void *)handle;
	unsigned long flags;

	spin_lock_irqsave(&ts->lock, flags);
	ad7877_ts_event_release(ts);
	spin_unlock_irqrestore(&ts->lock, flags);
}


Contributors
PersonTokensPropCommitsCommitProp
Michael Hennerich2652.00%150.00%


Dmitry Torokhov2448.00%150.00%


Total50100.00%2100.00%






static irqreturn_t ad7877_irq(int irq, void *handle)
{
	struct ad7877 *ts = handle;
	unsigned long flags;
	int error;

	error = spi_sync(ts->spi, &ts->msg);
	if (error) {
		dev_err(&ts->spi->dev, "spi_sync --> %d\n", error);
		goto out;
	}

	spin_lock_irqsave(&ts->lock, flags);
	error = ad7877_process_data(ts);
	if (!error)
		mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
	spin_unlock_irqrestore(&ts->lock, flags);

out:
	return IRQ_HANDLED;
}


Contributors
PersonTokensPropCommitsCommitProp
Michael Hennerich9180.53%266.67%


Dmitry Torokhov2219.47%133.33%


Total113100.00%3100.00%






static void ad7877_disable(struct ad7877 *ts)
{
	mutex_lock(&ts->mutex);

	if (!ts->disabled) {
		ts->disabled = true;
		disable_irq(ts->spi->irq);

		if (del_timer_sync(&ts->timer))
			ad7877_ts_event_release(ts);
	}

	/*
         * We know the chip's in lowpower mode since we always
         * leave it that way after every request
         */

	mutex_unlock(&ts->mutex);
}


Contributors
PersonTokensPropCommitsCommitProp
Michael Hennerich6597.01%150.00%


Dmitry Torokhov22.99%150.00%


Total67100.00%2100.00%






static void ad7877_enable(struct ad7877 *ts)
{
	mutex_lock(&ts->mutex);

	if (ts->disabled) {
		ts->disabled = false;
		enable_irq(ts->spi->irq);
	}

	mutex_unlock(&ts->mutex);
}


Contributors
PersonTokensPropCommitsCommitProp
Michael Hennerich4998.00%150.00%


Dmitry Torokhov12.00%150.00%


Total50100.00%2100.00%




#define SHOW(name) static ssize_t \
name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
{ \
        struct ad7877 *ts = dev_get_drvdata(dev); \
        ssize_t v = ad7877_read_adc(ts->spi, \
                        AD7877_READ_CHAN(name)); \
        if (v < 0) \
                return v; \
        return sprintf(buf, "%u\n", (unsigned) v); \
} \
static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);

SHOW(aux1)
SHOW(aux2)
SHOW(aux3)
SHOW(bat1)
SHOW(bat2)
SHOW(temp1)
SHOW(temp2)




static ssize_t ad7877_disable_show(struct device *dev,
				     struct device_attribute *attr, char *buf)
{
	struct ad7877 *ts = dev_get_drvdata(dev);

	return sprintf(buf, "%u\n", ts->disabled);
}


Contributors
PersonTokensPropCommitsCommitProp
Michael Hennerich42100.00%1100.00%


Total42100.00%1100.00%






static ssize_t ad7877_disable_store(struct device *dev,
				     struct device_attribute *attr,
				     const char *buf, size_t count)
{
	struct ad7877 *ts = dev_get_drvdata(dev);
	unsigned int val;
	int error;

	error = kstrtouint(buf, 10, &val);
	if (error)
		return error;

	if (val)
		ad7877_disable(ts);
	else
		ad7877_enable(ts);

	return count;
}


Contributors
PersonTokensPropCommitsCommitProp
Michael Hennerich7697.44%150.00%


JJ Ding22.56%150.00%


Total78100.00%2100.00%



static DEVICE_ATTR(disable, 0664, ad7877_disable_show, ad7877_disable_store);




static ssize_t ad7877_dac_show(struct device *dev,
				     struct device_attribute *attr, char *buf)
{
	struct ad7877 *ts = dev_get_drvdata(dev);

	return sprintf(buf, "%u\n", ts->dac);
}


Contributors
PersonTokensPropCommitsCommitProp
Michael Hennerich42100.00%1100.00%


Total42100.00%1100.00%






static ssize_t ad7877_dac_store(struct device *dev,
				     struct device_attribute *attr,
				     const char *buf, size_t count)
{
	struct ad7877 *ts = dev_get_drvdata(dev);
	unsigned int val;
	int error;

	error = kstrtouint(buf, 10, &val);
	if (error)
		return error;

	mutex_lock(&ts->mutex);
	ts->dac = val & 0xFF;
	ad7877_write(ts->spi, AD7877_REG_DAC, (ts->dac << 4) | AD7877_DAC_CONF);
	mutex_unlock(&ts->mutex);

	return count;
}


Contributors
PersonTokensPropCommitsCommitProp
Michael Hennerich10498.11%150.00%


JJ Ding21.89%150.00%


Total106100.00%2100.00%



static DEVICE_ATTR(dac, 0664, ad7877_dac_show, ad7877_dac_store);




static ssize_t ad7877_gpio3_show(struct device *dev,
				     struct device_attribute *attr, char *buf)
{
	struct ad7877 *ts = dev_get_drvdata(dev);

	return sprintf(buf, "%u\n", ts->gpio3);
}


Contributors
PersonTokensPropCommitsCommitProp
Michael Hennerich42100.00%1100.00%


Total42100.00%1100.00%






static ssize_t ad7877_gpio3_store(struct device *dev,
				     struct device_attribute *attr,
				     const char *buf, size_t count)
{
	struct ad7877 *ts = dev_get_drvdata(dev);
	unsigned int val;
	int error;

	error = kstrtouint(buf, 10, &val);
	if (error)
		return error;

	mutex_lock(&ts->mutex);
	ts->gpio3 = !!val;
	ad7877_write(ts->spi, AD7877_REG_EXTWRITE, AD7877_EXTW_GPIO_DATA |
		 (ts->gpio4 << 4) | (ts->gpio3 << 5));
	mutex_unlock(&ts->mutex);

	return count;
}


Contributors
PersonTokensPropCommitsCommitProp
Michael Hennerich11298.25%150.00%


JJ Ding21.75%150.00%


Total114100.00%2100.00%



static DEVICE_ATTR(gpio3, 0664, ad7877_gpio3_show, ad7877_gpio3_store);




static ssize_t ad7877_gpio4_show(struct device *dev,
				     struct device_attribute *attr, char *buf)
{
	struct ad7877 *ts = dev_get_drvdata(dev);

	return sprintf(buf, "%u\n", ts->gpio4);
}


Contributors
PersonTokensPropCommitsCommitProp
Michael Hennerich42100.00%1100.00%


Total42100.00%1100.00%






static ssize_t ad7877_gpio4_store(struct device *dev,
				     struct device_attribute *attr,
				     const char *buf, size_t count)
{
	struct ad7877 *ts = dev_get_drvdata(dev);
	unsigned int val;
	int error;

	error = kstrtouint(buf, 10, &val);
	if (error)
		return error;

	mutex_lock(&ts->mutex);
	ts->gpio4 = !!val;
	ad7877_write(ts->spi, AD7877_REG_EXTWRITE, AD7877_EXTW_GPIO_DATA |
		     (ts->gpio4 << 4) | (ts->gpio3 << 5));
	mutex_unlock(&ts->mutex);

	return count;
}


Contributors
PersonTokensPropCommitsCommitProp
Michael Hennerich11298.25%150.00%


JJ Ding21.75%150.00%


Total114100.00%2100.00%



static DEVICE_ATTR(gpio4, 0664, ad7877_gpio4_show, ad7877_gpio4_store);


static struct attribute *ad7877_attributes[] = {
	&dev_attr_temp1.attr,
	&dev_attr_temp2.attr,
	&dev_attr_aux1.attr,
	&dev_attr_aux2.attr,
	&dev_attr_aux3.attr,
	&dev_attr_bat1.attr,
	&dev_attr_bat2.attr,
	&dev_attr_disable.attr,
	&dev_attr_dac.attr,
	&dev_attr_gpio3.attr,
	&dev_attr_gpio4.attr,
	NULL
};




static umode_t ad7877_attr_is_visible(struct kobject *kobj,
				     struct attribute *attr, int n)
{
	umode_t mode = attr->mode;

	if (attr == &dev_attr_aux3.attr) {
		if (gpio3)
			mode = 0;
	} else if (attr == &dev_attr_gpio3.attr) {
		if (!gpio3)
			mode = 0;
	}

	return mode;
}


Contributors
PersonTokensPropCommitsCommitProp
Dmitry Torokhov6797.10%150.00%


Al Viro22.90%150.00%


Total69100.00%2100.00%




static const struct attribute_group ad7877_attr_group = {
	.is_visible	= ad7877_attr_is_visible,
	.attrs		= ad7877_attributes,
};




static void ad7877_setup_ts_def_msg(struct spi_device *spi, struct ad7877 *ts)
{
	struct spi_message *m;
	int i;

	ts->cmd_crtl2 = AD7877_WRITEADD(AD7877_REG_CTRL2) |
			AD7877_POL(ts->stopacq_polarity) |
			AD7877_AVG(ts->averaging) | AD7877_PM(1) |
			AD7877_TMR(ts->pen_down_acc_interval) |
			AD7877_ACQ(ts->acquisition_time) |
			AD7877_FCD(ts->first_conversion_delay);

	ad7877_write(spi, AD7877_REG_CTRL2, ts->cmd_crtl2);

	ts->cmd_crtl1 = AD7877_WRITEADD(AD7877_REG_CTRL1) |
			AD7877_READADD(AD7877_REG_XPLUS-1) |
			AD7877_MODE_SEQ1 | AD7877_DFR;

	ad7877_write(spi, AD7877_REG_CTRL1, ts->cmd_crtl1);

	ts->cmd_dummy = 0;

	m = &ts->msg;

	spi_message_init(m);

	m->context = ts;

	ts->xfer[0].tx_buf = &ts->cmd_crtl1;
	ts->xfer[0].len = 2;
	ts->xfer[0].cs_change = 1;

	spi_message_add_tail(&ts->xfer[0], m);

	ts->xfer[1].tx_buf = &ts->cmd_dummy; /* Send ZERO */
	ts->xfer[1].len = 2;
	ts->xfer[1].cs_change = 1;

	spi_message_add_tail(&ts->xfer[1], m);

	for (i = 0; i < AD7877_NR_SENSE; i++) {
		ts->xfer[i + 2].rx_buf = &ts->conversion_data[AD7877_SEQ_YPOS + i];
		ts->xfer[i + 2].len = 2;
		if (i < (AD7877_NR_SENSE - 1))
			ts->xfer[i + 2].cs_change = 1;
		spi_message_add_tail(&ts->xfer[i + 2], m);
	}
}


Contributors
PersonTokensPropCommitsCommitProp
Michael Hennerich325100.00%2100.00%


Total325100.00%2100.00%






static int ad7877_probe(struct spi_device *spi)
{
	struct ad7877			*ts;
	struct input_dev		*input_dev;
	struct ad7877_platform_data	*pdata = dev_get_platdata(&<