[Letux-kernel] [PATCH v5 4/8] drivers:input:tsc2007: add iio interface to read external ADC input and temperature

Jonathan Cameron jic23 at kernel.org
Sun Oct 30 17:42:55 CET 2016


On 25/10/16 20:26, H. Nikolaus Schaller wrote:
> The tsc2007 chip not only has a resistive touch screen controller but
> also an external AUX adc imput which can be used for an ambient
> light sensor, battery voltage monitoring or any general purpose.
> 
> Additionally it can measure the chip temperature.
> 
> This extension provides an iio interface for these adc channels.
> 
> Since it is not wasting much resources and is very straightforward,
> we simply provide all other adc channels as optional iio interfaces
> as weel. This can be used for debugging or special applications.
well
> 
> This patch also splits the tsc2007 driver in several source files:
> tsc2007.h -- constants, structs and stubs
> tsc2007_core.c -- functional parts of the original driver
> tsc2007_iio.c -- the optional iio stuff
> 
> Makefile magic allows to conditionally link the iio
> stuff if CONFIG_IIO=y in a way that it works with
> CONFIG_TOUCHSCREEN_TSC2007=m.
> 
> Signed-off-by: H. Nikolaus Schaller <hns at goldelico.com>
Basically sound, just a few minor bits inline.  In particular the point
about including iio.h (and it applies to input.h etc) in your header.

You can define a pointer to a struct iio_dev without having to let the compiler
know what is actually in it - as long as you don't dereference it in any
place where the compiler needs to know.

Couple of examples in for example drivers/iio/adc/xilinx-xadc.h
The struct clk; stuff is just what we need here for example.

All about keeping internal structures opaque where we don't need to know
what is in them.

Anyhow, nearly there! (as far as I'm concerned anyway)

Thanks,

Jonathan
> ---
>  drivers/input/touchscreen/Makefile                 |   2 +
>  drivers/input/touchscreen/tsc2007.h                | 124 ++++++++++++++++
>  .../touchscreen/{tsc2007.c => tsc2007_core.c}      | 119 +++++----------
>  drivers/input/touchscreen/tsc2007_iio.c            | 162 +++++++++++++++++++++
>  4 files changed, 323 insertions(+), 84 deletions(-)
>  create mode 100644 drivers/input/touchscreen/tsc2007.h
>  rename drivers/input/touchscreen/{tsc2007.c => tsc2007_core.c} (85%)
>  create mode 100644 drivers/input/touchscreen/tsc2007_iio.c
> 
> diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
> index 81b8645..d932e2d 100644
> --- a/drivers/input/touchscreen/Makefile
> +++ b/drivers/input/touchscreen/Makefile
> @@ -80,6 +80,8 @@ obj-$(CONFIG_TOUCHSCREEN_TSC_SERIO)	+= tsc40.o
>  obj-$(CONFIG_TOUCHSCREEN_TSC200X_CORE)	+= tsc200x-core.o
>  obj-$(CONFIG_TOUCHSCREEN_TSC2004)	+= tsc2004.o
>  obj-$(CONFIG_TOUCHSCREEN_TSC2005)	+= tsc2005.o
> +tsc2007-y				:= tsc2007_core.o
> +tsc2007-$(CONFIG_IIO)			+= tsc2007_iio.o
>  obj-$(CONFIG_TOUCHSCREEN_TSC2007)	+= tsc2007.o
>  obj-$(CONFIG_TOUCHSCREEN_UCB1400)	+= ucb1400_ts.o
>  obj-$(CONFIG_TOUCHSCREEN_WACOM_W8001)	+= wacom_w8001.o
> diff --git a/drivers/input/touchscreen/tsc2007.h b/drivers/input/touchscreen/tsc2007.h
> new file mode 100644
> index 0000000..7153bf3
> --- /dev/null
> +++ b/drivers/input/touchscreen/tsc2007.h
> @@ -0,0 +1,124 @@
> +/*
> + * drivers/input/touchscreen/tsc2007.h
> + *
> + * Copyright (c) 2008 MtekVision Co., Ltd.
> + *	Kwangwoo Lee <kwlee at mtekvision.com>
> + *
> + * Using code from:
> + *  - ads7846.c
> + *	Copyright (c) 2005 David Brownell
> + *	Copyright (c) 2006 Nokia Corporation
> + *  - 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/module.h>
> +#include <linux/slab.h>
> +#include <linux/input.h>
You shouldn't need to include input.h in here...
(see below comment on the struct iio_dev *
> +#include <linux/interrupt.h>
> +#include <linux/i2c.h>
> +#include <linux/i2c/tsc2007.h>
> +#include <linux/of_device.h>
> +#include <linux/of.h>
> +#include <linux/of_gpio.h>
> +#include <linux/input/touchscreen.h>
Not sure why this is included either here.
> +
> +#define TSC2007_MEASURE_TEMP0		(0x0 << 4)
> +#define TSC2007_MEASURE_AUX		(0x2 << 4)
> +#define TSC2007_MEASURE_TEMP1		(0x4 << 4)
> +#define TSC2007_ACTIVATE_XN		(0x8 << 4)
> +#define TSC2007_ACTIVATE_YN		(0x9 << 4)
> +#define TSC2007_ACTIVATE_YP_XN		(0xa << 4)
> +#define TSC2007_SETUP			(0xb << 4)
> +#define TSC2007_MEASURE_X		(0xc << 4)
> +#define TSC2007_MEASURE_Y		(0xd << 4)
> +#define TSC2007_MEASURE_Z1		(0xe << 4)
> +#define TSC2007_MEASURE_Z2		(0xf << 4)
> +
> +#define TSC2007_POWER_OFF_IRQ_EN	(0x0 << 2)
> +#define TSC2007_ADC_ON_IRQ_DIS0		(0x1 << 2)
> +#define TSC2007_ADC_OFF_IRQ_EN		(0x2 << 2)
> +#define TSC2007_ADC_ON_IRQ_DIS1		(0x3 << 2)
> +
> +#define TSC2007_12BIT			(0x0 << 1)
> +#define TSC2007_8BIT			(0x1 << 1)
> +
> +#define	MAX_12BIT			((1 << 12) - 1)
> +
> +#define ADC_ON_12BIT	(TSC2007_12BIT | TSC2007_ADC_ON_IRQ_DIS0)
> +
> +#define READ_Y		(ADC_ON_12BIT | TSC2007_MEASURE_Y)
> +#define READ_Z1		(ADC_ON_12BIT | TSC2007_MEASURE_Z1)
> +#define READ_Z2		(ADC_ON_12BIT | TSC2007_MEASURE_Z2)
> +#define READ_X		(ADC_ON_12BIT | TSC2007_MEASURE_X)
> +#define PWRDOWN		(TSC2007_12BIT | TSC2007_POWER_OFF_IRQ_EN)
> +
> +struct ts_event {
> +	u16	x;
> +	u16	y;
> +	u16	z1, z2;
> +};
> +
> +struct tsc2007 {
> +	struct input_dev	*input;
> +	char			phys[32];
> +
> +	struct i2c_client	*client;
> +
> +	u16			model;
> +	u16			x_plate_ohms;
> +
> +	struct touchscreen_properties prop;
> +
> +	bool			report_resistance;
> +	u16			min_x;
> +	u16			min_y;
> +	u16			max_x;
> +	u16			max_y;
> +	u16			max_rt;
> +	unsigned long		poll_period; /* in jiffies */
> +	int			fuzzx;
> +	int			fuzzy;
> +	int			fuzzz;
> +
> +	unsigned int		gpio;
> +	int			irq;
> +
> +	wait_queue_head_t	wait;
> +	bool			stopped;
> +	bool			pendown;
> +
> +	int			(*get_pendown_state)(struct device *);
> +	void			(*clear_penirq)(void);
> +
> +	struct mutex		mlock;
> +#ifdef CONFIG_IIO
I don't like this.  Nothing stops you using a struct iio_dev * pointer
without including iio.h.  It's a commmon thing to do.  Just put
struct *iio_dev above and don't ever dereference it without having include
iio.h in the file.
> +	void			*private;
> +#endif
> +};
> +
> +int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd);
> +u32 tsc2007_calculate_resistance(struct tsc2007 *tsc,
> +					struct ts_event *tc);
> +bool tsc2007_is_pen_down(struct tsc2007 *ts);
> +
> +#ifdef CONFIG_IIO
> +
> +/* defined in tsc2007_iio.c */
> +int tsc2007_iio_configure(struct tsc2007 *ts);
> +void tsc2007_iio_unconfigure(struct tsc2007 *ts);
> +
> +#else /* CONFIG_IIO */
> +
> +static inline int tsc2007_iio_configure(struct tsc2007 *ts) { }
should return 0.
> +static inline void tsc2007_iio_unconfigure(struct tsc2007 *ts) { }
> +
> +#endif /* CONFIG_IIO */
> diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007_core.c
> similarity index 85%
> rename from drivers/input/touchscreen/tsc2007.c
> rename to drivers/input/touchscreen/tsc2007_core.c
> index 5e3c4bf..19dfc9b 100644
> --- a/drivers/input/touchscreen/tsc2007.c
> +++ b/drivers/input/touchscreen/tsc2007_core.c
> @@ -20,87 +20,9 @@
>   *  published by the Free Software Foundation.
>   */
>  
> -#include <linux/module.h>
> -#include <linux/slab.h>
> -#include <linux/input.h>
> -#include <linux/interrupt.h>
> -#include <linux/i2c.h>
> -#include <linux/i2c/tsc2007.h>
> -#include <linux/of_device.h>
> -#include <linux/of.h>
> -#include <linux/of_gpio.h>
> -#include <linux/input/touchscreen.h>
> -
> -#define TSC2007_MEASURE_TEMP0		(0x0 << 4)
> -#define TSC2007_MEASURE_AUX		(0x2 << 4)
> -#define TSC2007_MEASURE_TEMP1		(0x4 << 4)
> -#define TSC2007_ACTIVATE_XN		(0x8 << 4)
> -#define TSC2007_ACTIVATE_YN		(0x9 << 4)
> -#define TSC2007_ACTIVATE_YP_XN		(0xa << 4)
> -#define TSC2007_SETUP			(0xb << 4)
> -#define TSC2007_MEASURE_X		(0xc << 4)
> -#define TSC2007_MEASURE_Y		(0xd << 4)
> -#define TSC2007_MEASURE_Z1		(0xe << 4)
> -#define TSC2007_MEASURE_Z2		(0xf << 4)
> -
> -#define TSC2007_POWER_OFF_IRQ_EN	(0x0 << 2)
> -#define TSC2007_ADC_ON_IRQ_DIS0		(0x1 << 2)
> -#define TSC2007_ADC_OFF_IRQ_EN		(0x2 << 2)
> -#define TSC2007_ADC_ON_IRQ_DIS1		(0x3 << 2)
> -
> -#define TSC2007_12BIT			(0x0 << 1)
> -#define TSC2007_8BIT			(0x1 << 1)
> -
> -#define	MAX_12BIT			((1 << 12) - 1)
> -
> -#define ADC_ON_12BIT	(TSC2007_12BIT | TSC2007_ADC_ON_IRQ_DIS0)
> -
> -#define READ_Y		(ADC_ON_12BIT | TSC2007_MEASURE_Y)
> -#define READ_Z1		(ADC_ON_12BIT | TSC2007_MEASURE_Z1)
> -#define READ_Z2		(ADC_ON_12BIT | TSC2007_MEASURE_Z2)
> -#define READ_X		(ADC_ON_12BIT | TSC2007_MEASURE_X)
> -#define PWRDOWN		(TSC2007_12BIT | TSC2007_POWER_OFF_IRQ_EN)
> -
> -struct ts_event {
> -	u16	x;
> -	u16	y;
> -	u16	z1, z2;
> -};
> -
> -struct tsc2007 {
> -	struct input_dev	*input;
> -	char			phys[32];
> -
> -	struct i2c_client	*client;
> -
> -	u16			model;
> -	u16			x_plate_ohms;
> -
> -	struct touchscreen_properties prop;
> -
> -	bool			report_resistance;
> -	u16			min_x;
> -	u16			min_y;
> -	u16			max_x;
> -	u16			max_y;
> -	u16			max_rt;
> -	unsigned long		poll_period; /* in jiffies */
> -	int			fuzzx;
> -	int			fuzzy;
> -	int			fuzzz;
> +#include "tsc2007.h"
>  
> -	unsigned		gpio;
> -	int			irq;
> -
> -	wait_queue_head_t	wait;
> -	bool			stopped;
> -	bool			pendown;
> -
> -	int			(*get_pendown_state)(struct device *);
> -	void			(*clear_penirq)(void);
> -};
> -
> -static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
> +int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
>  {
>  	s32 data;
>  	u16 val;
> @@ -121,6 +43,7 @@ static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
>  
>  	return val;
>  }
> +EXPORT_SYMBOL(tsc2007_xfer);
>  
>  static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
>  {
> @@ -138,7 +61,7 @@ static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
>  	tsc2007_xfer(tsc, PWRDOWN);
>  }
>  
> -static u32 tsc2007_calculate_resistance(struct tsc2007 *tsc,
> +u32 tsc2007_calculate_resistance(struct tsc2007 *tsc,
>  					struct ts_event *tc)
>  {
>  	u32 rt = 0;
> @@ -158,8 +81,9 @@ static u32 tsc2007_calculate_resistance(struct tsc2007 *tsc,
>  
>  	return rt;
>  }
> +EXPORT_SYMBOL(tsc2007_calculate_resistance);
>  
> -static bool tsc2007_is_pen_down(struct tsc2007 *ts)
> +bool tsc2007_is_pen_down(struct tsc2007 *ts)
>  {
>  	/*
>  	 * NOTE: We can't rely on the pressure to determine the pen down
> @@ -180,6 +104,7 @@ static bool tsc2007_is_pen_down(struct tsc2007 *ts)
>  
>  	return ts->get_pendown_state(&ts->client->dev);
>  }
> +EXPORT_SYMBOL(tsc2007_is_pen_down);
>  
>  static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
>  {
> @@ -192,7 +117,10 @@ static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
>  	while (!ts->stopped && tsc2007_is_pen_down(ts)) {
>  
>  		/* pen is down, continue with the measurement */
> +
> +		mutex_lock(&ts->mlock);
>  		tsc2007_read_values(ts, &tc);
> +		mutex_unlock(&ts->mlock);
>  
>  		rt = tsc2007_calculate_resistance(ts, &tc);
>  
> @@ -450,7 +378,8 @@ static void tsc2007_call_exit_platform_hw(void *data)
>  static int tsc2007_probe(struct i2c_client *client,
>  			 const struct i2c_device_id *id)
>  {
> -	const struct tsc2007_platform_data *pdata = dev_get_platdata(&client->dev);
> +	const struct tsc2007_platform_data *pdata =
> +		dev_get_platdata(&client->dev);
>  	struct tsc2007 *ts;
>  	struct input_dev *input_dev;
>  	int err;
> @@ -472,7 +401,13 @@ static int tsc2007_probe(struct i2c_client *client,
>  	ts->client = client;
>  	ts->irq = client->irq;
>  	ts->input = input_dev;
> +
> +	err = tsc2007_iio_configure(ts);
> +	if (err < 0)
> +		return err;
> +
>  	init_waitqueue_head(&ts->wait);
> +	mutex_init(&ts->mlock);
>  
>  	snprintf(ts->phys, sizeof(ts->phys),
>  		 "%s/input0", dev_name(&client->dev));
> @@ -503,8 +438,10 @@ static int tsc2007_probe(struct i2c_client *client,
>  							  ts->fuzzz, 0);
>  	} else {
>  		err = tsc2007_probe_dt(client, ts);
> -		if (err)
> +		if (err) {
> +			tsc2007_iio_unconfigure(ts);
>  			return err;
> +		}
>  	}
>  
>  	if (pdata) {
> @@ -516,6 +453,7 @@ static int tsc2007_probe(struct i2c_client *client,
>  				dev_err(&client->dev,
>  					"Failed to register exit_platform_hw action, %d\n",
>  					err);
> +				tsc2007_iio_unconfigure(ts);
>  				return err;
>  			}
>  		}
> @@ -533,6 +471,7 @@ static int tsc2007_probe(struct i2c_client *client,
>  	if (err) {
>  		dev_err(&client->dev, "Failed to request irq %d: %d\n",
>  			ts->irq, err);
> +		tsc2007_iio_unconfigure(ts);
>  		return err;
>  	}
>  
> @@ -543,6 +482,7 @@ static int tsc2007_probe(struct i2c_client *client,
>  	if (err < 0) {
>  		dev_err(&client->dev,
>  			"Failed to setup chip: %d\n", err);
> +		tsc2007_iio_unconfigure(ts);
>  		return err;	/* usually, chip does not respond */
>  	}
>  
> @@ -550,12 +490,22 @@ static int tsc2007_probe(struct i2c_client *client,
>  	if (err) {
>  		dev_err(&client->dev,
>  			"Failed to register input device: %d\n", err);
> +		tsc2007_iio_unconfigure(ts);
>  		return err;
>  	}
>  
>  	return 0;
>  }
>  
> +static int tsc2007_remove(struct i2c_client *client)
> +{
> +	struct tsc2007 *ts = i2c_get_clientdata(client);
> +
> +	tsc2007_iio_unconfigure(ts);
> +	input_unregister_device(ts->input);
> +	return 0;
> +}
> +
>  static const struct i2c_device_id tsc2007_idtable[] = {
>  	{ "tsc2007", 0 },
>  	{ }
> @@ -578,6 +528,7 @@ static struct i2c_driver tsc2007_driver = {
>  	},
>  	.id_table	= tsc2007_idtable,
>  	.probe		= tsc2007_probe,
> +	.remove		= tsc2007_remove,
>  };
>  
>  module_i2c_driver(tsc2007_driver);
> diff --git a/drivers/input/touchscreen/tsc2007_iio.c b/drivers/input/touchscreen/tsc2007_iio.c
> new file mode 100644
> index 0000000..608db45
> --- /dev/null
> +++ b/drivers/input/touchscreen/tsc2007_iio.c
> @@ -0,0 +1,162 @@
> +/*
> + * drivers/input/touchscreen/tsc2007_iio.c
> + *
> + * Copyright (c) 2008 MtekVision Co., Ltd.
> + *	Kwangwoo Lee <kwlee at mtekvision.com>
> + *
> + * Using code from:
> + *  - ads7846.c
> + *	Copyright (c) 2005 David Brownell
> + *	Copyright (c) 2006 Nokia Corporation
> + *  - 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 "tsc2007.h"
> +#include <linux/iio/iio.h>
> +
> +struct tsc2007_iio {
> +	struct tsc2007 *ts;
> +};
> +
> +#define TSC2007_CHAN_IIO(_chan, _name, _type, _chan_info) \
> +{ \
> +	.datasheet_name = _name, \
> +	.type = _type, \
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	\
> +			BIT(_chan_info), \
> +	.indexed = 1, \
> +	.channel = _chan, \
> +}
> +
> +static const struct iio_chan_spec tsc2007_iio_channel[] = {
> +	TSC2007_CHAN_IIO(0, "x", IIO_VOLTAGE, IIO_CHAN_INFO_RAW),
> +	TSC2007_CHAN_IIO(1, "y", IIO_VOLTAGE, IIO_CHAN_INFO_RAW),
> +	TSC2007_CHAN_IIO(2, "z1", IIO_VOLTAGE, IIO_CHAN_INFO_RAW),
> +	TSC2007_CHAN_IIO(3, "z2", IIO_VOLTAGE, IIO_CHAN_INFO_RAW),
> +	TSC2007_CHAN_IIO(4, "adc", IIO_VOLTAGE, IIO_CHAN_INFO_RAW),
> +	TSC2007_CHAN_IIO(5, "rt", IIO_VOLTAGE, IIO_CHAN_INFO_RAW), /* Ohms? */
> +	TSC2007_CHAN_IIO(6, "pen", IIO_PRESSURE, IIO_CHAN_INFO_RAW),
> +	TSC2007_CHAN_IIO(7, "temp0", IIO_TEMP, IIO_CHAN_INFO_RAW),
> +	TSC2007_CHAN_IIO(8, "temp1", IIO_TEMP, IIO_CHAN_INFO_RAW),
> +};
> +
> +static int tsc2007_read_raw(struct iio_dev *indio_dev,
> +	struct iio_chan_spec const *chan, int *val, int *val2, long mask)
> +{
> +	struct tsc2007_iio *iio = iio_priv(indio_dev);
> +	struct tsc2007 *tsc = iio->ts;
> +	int adc_chan = chan->channel;
> +	int ret = 0;
> +
> +	if (adc_chan >= ARRAY_SIZE(tsc2007_iio_channel))
> +		return -EINVAL;
> +
> +	if (mask != IIO_CHAN_INFO_RAW)
> +		return -EINVAL;
> +
> +	mutex_lock(&tsc->mlock);
> +
> +	switch (chan->channel) {
> +	case 0:
> +		*val = tsc2007_xfer(tsc, READ_X);
> +		break;
> +	case 1:
> +		*val = tsc2007_xfer(tsc, READ_Y);
> +		break;
> +	case 2:
> +		*val = tsc2007_xfer(tsc, READ_Z1);
> +		break;
> +	case 3:
> +		*val = tsc2007_xfer(tsc, READ_Z2);
> +		break;
> +	case 4:
> +		*val = tsc2007_xfer(tsc, (ADC_ON_12BIT | TSC2007_MEASURE_AUX));
> +		break;
> +	case 5: {
> +		struct ts_event tc;
> +
> +		tc.x = tsc2007_xfer(tsc, READ_X);
> +		tc.z1 = tsc2007_xfer(tsc, READ_Z1);
> +		tc.z2 = tsc2007_xfer(tsc, READ_Z2);
> +		*val = tsc2007_calculate_resistance(tsc, &tc);
> +		break;
> +	}
> +	case 6:
> +		*val = tsc2007_is_pen_down(tsc);
> +		break;
> +	case 7:
> +		*val = tsc2007_xfer(tsc,
> +				    (ADC_ON_12BIT | TSC2007_MEASURE_TEMP0));
> +		break;
> +	case 8:
> +		*val = tsc2007_xfer(tsc,
> +				    (ADC_ON_12BIT | TSC2007_MEASURE_TEMP1));
> +		break;
> +	}
> +
> +	/* Prepare for next touch reading - power down ADC, enable PENIRQ */
> +	tsc2007_xfer(tsc, PWRDOWN);
> +
> +	mutex_unlock(&tsc->mlock);
> +
> +	ret = IIO_VAL_INT;
> +
> +	return ret;
return IIO_VAL_INT;

Though feels like tsc2007_xfer might return an error and should
be handled...
> +}
> +
> +static const struct iio_info tsc2007_iio_info = {
> +	.read_raw = tsc2007_read_raw,
> +	.driver_module = THIS_MODULE,
> +};
> +
> +int tsc2007_iio_configure(struct tsc2007 *ts)
> +{
> +	int err;
> +	struct iio_dev *indio_dev;
> +	struct tsc2007_iio *iio;
> +
> +	indio_dev = devm_iio_device_alloc(&ts->client->dev,
> +		sizeof(struct tsc2007_iio));
> +	if (!indio_dev) {
> +		dev_err(&ts->client->dev, "iio_device_alloc failed\n");
> +		return -ENOMEM;
> +	}
> +
> +	iio = iio_priv(indio_dev);
> +	iio->ts = ts;
> +	ts->private = (void *) indio_dev;
> +
> +	indio_dev->name = "tsc2007";
> +	indio_dev->dev.parent = &ts->client->dev;
> +	indio_dev->info = &tsc2007_iio_info;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->channels = tsc2007_iio_channel;
> +	indio_dev->num_channels = ARRAY_SIZE(tsc2007_iio_channel);
> +
> +	err = iio_device_register(indio_dev);
> +	if (err < 0) {
> +		dev_err(&ts->client->dev, "iio_device_register() failed: %d\n",
> +			err);
> +		return err;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(tsc2007_iio_configure);
> +
> +void tsc2007_iio_unconfigure(struct tsc2007 *ts)
> +{
> +	struct iio_dev *indio_dev = ts->private;
> +
> +	iio_device_unregister(indio_dev);
> +}
> +EXPORT_SYMBOL(tsc2007_iio_unconfigure);
> 



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