Re: [PATCH v9 8/8] drivers:input:tsc2007: add iio interface to read external ADC input and temperature

[Dmitry Torokhov <dmitry.torokhov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On Fri, Dec 30, 2016 at 08:36:30PM +0000, Jonathan Cameron wrote:
> On 28/12/16 14:53, 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.
> > 
> > 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 or =m in a way that it works with
> > CONFIG_TOUCHSCREEN_TSC2007=m.
> > 
> > Signed-off-by: H. Nikolaus Schaller <hns-xXXSsgcRVICgSpxsJD1C4w@public.gmane.org>
> > Reviewed-by: Jonathan Cameron <jic23-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> Just for the record, I'm happy with the few changes from earlier versions.

I untangled this from the rest of the patches (as it turned out to be
the least controversial ;) ) and applied with some minor changes (see
below). Please take a look at my tsc2007 branch on kernel.org to see if
I missed anything.

Thanks.

> 
> Jonathan
> > ---
> >  drivers/input/touchscreen/Kconfig                  |  10 ++
> >  drivers/input/touchscreen/Makefile                 |   2 +
> >  drivers/input/touchscreen/tsc2007.h                | 116 ++++++++++++++++
> >  .../touchscreen/{tsc2007.c => tsc2007_core.c}      |  95 +++----------
> >  drivers/input/touchscreen/tsc2007_iio.c            | 150 +++++++++++++++++++++
> >  5 files changed, 299 insertions(+), 74 deletions(-)
> >  create mode 100644 drivers/input/touchscreen/tsc2007.h
> >  rename drivers/input/touchscreen/{tsc2007.c => tsc2007_core.c} (86%)
> >  create mode 100644 drivers/input/touchscreen/tsc2007_iio.c
> > 
> > diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> > index efca013..1616a8d 100644
> > --- a/drivers/input/touchscreen/Kconfig
> > +++ b/drivers/input/touchscreen/Kconfig
> > @@ -1035,6 +1035,16 @@ config TOUCHSCREEN_TSC2007
> >  	  To compile this driver as a module, choose M here: the
> >  	  module will be called tsc2007.
> >  
> > +config TOUCHSCREEN_TSC2007_IIO
> > +	bool "IIO interface for external ADC input and temperature"
> > +	depends on TOUCHSCREEN_TSC2007
> > +	depends on IIO=y || IIO=TOUCHSCREEN_TSC2007
> > +	help
> > +	  Saying Y here adds an iio interface to the tsc2007 which
> > +	  provides values for the AUX input (used for e.g. battery
> > +	  or ambient light monitoring), temperature and raw input
> > +	  values.
> > +
> >  config TOUCHSCREEN_W90X900
> >  	tristate "W90P910 touchscreen driver"
> >  	depends on ARCH_W90X900
> > diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
> > index 81b8645..05d1cc8 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-$(CONFIG_TOUCHSCREEN_TSC2007_IIO)	+= tsc2007_iio.o
> >  obj-$(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..16efb60
> > --- /dev/null
> > +++ b/drivers/input/touchscreen/tsc2007.h
> > @@ -0,0 +1,116 @@
> > +/*
> > + * Copyright (c) 2008 MtekVision Co., Ltd.
> > + *	Kwangwoo Lee <kwlee-ec7hoAtq5SbSUeElwK9/Pw@public.gmane.org>
> > + *
> > + * 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/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;
> > +
> > +	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;
> > +	struct iio_dev		*iio_dev;	/* optional */
> > +};
> > +
> > +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);
> > +
> > +#if IS_ENABLED(CONFIG_TOUCHSCREEN_TSC2007_IIO)
> > +
> > +/* defined in tsc2007_iio.c */
> > +int tsc2007_iio_configure(struct tsc2007 *ts);
> > +void tsc2007_iio_unconfigure(struct tsc2007 *ts);
> > +
> > +#else /* CONFIG_TOUCHSCREEN_TSC2007_IIO */
> > +
> > +static inline int tsc2007_iio_configure(struct tsc2007 *ts)
> > +{
> > +	return 0;
> > +}
> > +static inline void tsc2007_iio_unconfigure(struct tsc2007 *ts)
> > +{
> > +}
> > +
> > +#endif /* CONFIG_TOUCHSCREEN_TSC2007_IIO */
> > diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007_core.c
> > similarity index 86%
> > rename from drivers/input/touchscreen/tsc2007.c
> > rename to drivers/input/touchscreen/tsc2007_core.c
> > index 76b462b..812ded8 100644
> > --- a/drivers/input/touchscreen/tsc2007.c
> > +++ b/drivers/input/touchscreen/tsc2007_core.c
> > @@ -27,79 +27,11 @@
> >  #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;
> > -
> > -	unsigned		gpio;
> > -	int			irq;
> > -
> > -	wait_queue_head_t	wait;
> > -	bool			stopped;
> > +#include "tsc2007.h"
> >  
> > -	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;
> > @@ -137,7 +69,7 @@ static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
> >  	tsc2007_xfer(tsc, PWRDOWN);
> >  }
> >  
> > -static u32 tsc2007_calculate_resistance(struct tsc2007 *tsc,

Kept as tsc2007_calculate_resistance for now.

> > +u32 tsc2007_calculate_resistance(struct tsc2007 *tsc,
> >  					struct ts_event *tc)
> >  {
> >  	u32 rt = 0;
> > @@ -158,7 +90,7 @@ static u32 tsc2007_calculate_resistance(struct tsc2007 *tsc,
> >  	return rt;
> >  }
> >  
> > -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
> > @@ -191,7 +123,10 @@ 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);
> >  
> > @@ -441,7 +376,8 @@ 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;
> > @@ -463,7 +399,9 @@ static int tsc2007_probe(struct i2c_client *client,
> >  	ts->client = client;
> >  	ts->irq = client->irq;
> >  	ts->input = input_dev;
> > +
> >  	init_waitqueue_head(&ts->wait);
> > +	mutex_init(&ts->mlock);
> >  
> >  	snprintf(ts->phys, sizeof(ts->phys),
> >  		 "%s/input0", dev_name(&client->dev));
> > @@ -534,7 +472,7 @@ static int tsc2007_probe(struct i2c_client *client,
> >  	if (err < 0) {
> >  		dev_err(&client->dev,
> >  			"Failed to setup chip: %d\n", err);
> > -		return err;	/* usually, chip does not respond */
> > +		return err;	/* chip does not respond */
> >  	}
> >  
> >  	err = input_register_device(input_dev);
> > @@ -544,6 +482,14 @@ static int tsc2007_probe(struct i2c_client *client,
> >  		return err;
> >  	}
> >  
> > +	return tsc2007_iio_configure(ts);
> > +}
> > +
> > +static int tsc2007_remove(struct i2c_client *client)
> > +{
> > +	struct tsc2007 *ts = i2c_get_clientdata(client);
> > +
> > +	tsc2007_iio_unconfigure(ts);
> >  	return 0;
> >  }
> >  
> > @@ -569,6 +515,7 @@ 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..ed79944
> > --- /dev/null
> > +++ b/drivers/input/touchscreen/tsc2007_iio.c
> > @@ -0,0 +1,150 @@
> > +/*
> > + * Copyright (c) 2016 Golden Delicious Comp. GmbH&Co. KG
> > + *	Nikolaus Schaller <hns-xXXSsgcRVICgSpxsJD1C4w@public.gmane.org>
> > + *
> > + *  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/i2c.h>
> > +#include <linux/iio/iio.h>
> > +#include "tsc2007.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;
> > +}
> > +
> > +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->iio_dev = (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);

Changed this to devm.

> > +	if (err < 0) {
> > +		dev_err(&ts->client->dev, "iio_device_register() failed: %d\n",
> > +			err);
> > +		return err;
> > +	}
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL(tsc2007_iio_configure);

This is not a separate module, there is no need to export this symbol.

> > +
> > +void tsc2007_iio_unconfigure(struct tsc2007 *ts)
> > +{
> > +	struct iio_dev *indio_dev = ts->iio_dev;
> > +
> > +	iio_device_unregister(indio_dev);
> > +}
> > +EXPORT_SYMBOL(tsc2007_iio_unconfigure);

Dropped this as not needed with devm.

-- 
Dmitry