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

Dmitry Torokhov
2017-02-17T21:27:34Z

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@goldelico.com>
> > Reviewed-by: Jonathan Cameron <jic23@kernel.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@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/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@goldelico.com>
> > + *
> > + * 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