Re: [PATCH v6 4/8] drivers:input:tsc2007: add iio interface to read external ADC input and temperature

From: Jonathan Cameron
Date: Sun Oct 30 2016 - 13:11:31 EST

On 27/10/16 09:44, 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 in a way that it works with
> CONFIG_TOUCHSCREEN_TSC2007=m.
>
> Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
oops. Missed this newer version. Replied to V5. Most of the comments are still
relevant I think.

J
> ---
> drivers/input/touchscreen/Makefile | 2 +
> drivers/input/touchscreen/tsc2007.h | 129 ++++++++++++++++++
> .../touchscreen/{tsc2007.c => tsc2007_core.c} | 127 ++++++-----------
> drivers/input/touchscreen/tsc2007_iio.c | 151 +++++++++++++++++++++
> 4 files changed, 320 insertions(+), 89 deletions(-)
> create mode 100644 drivers/input/touchscreen/tsc2007.h
> rename drivers/input/touchscreen/{tsc2007.c => tsc2007_core.c} (84%)
> 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..87d5ce5
> --- /dev/null
> +++ b/drivers/input/touchscreen/tsc2007.h
> @@ -0,0 +1,129 @@
> +/*
> + * drivers/input/touchscreen/tsc2007.h
> + *
> + * Copyright (c) 2008 MtekVision Co., Ltd.
> + * Kwangwoo Lee <kwlee@xxxxxxxxxxxxxx>
> + *
> + * 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>
> +#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;
> +
> + 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
> + 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)
> +{
> + 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 84%
> rename from drivers/input/touchscreen/tsc2007.c
> rename to drivers/input/touchscreen/tsc2007_core.c
> index 5e3c4bf..56c9a52 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));
> @@ -494,7 +429,7 @@ static int tsc2007_probe(struct i2c_client *client,
> if (pdata) {
> err = tsc2007_probe_pdev(client, ts, pdata, id);
> if (err)
> - return err;
> + goto probe_err;
> input_set_abs_params(input_dev, ABS_X, 0, ts->max_x-ts->min_x,
> ts->fuzzx, 0);
> input_set_abs_params(input_dev, ABS_Y, 0, ts->max_y-ts->min_y,
> @@ -504,7 +439,7 @@ static int tsc2007_probe(struct i2c_client *client,
> } else {
> err = tsc2007_probe_dt(client, ts);
> if (err)
> - return err;
> + goto probe_err;
> }
>
> if (pdata) {
> @@ -516,7 +451,7 @@ static int tsc2007_probe(struct i2c_client *client,
> dev_err(&client->dev,
> "Failed to register exit_platform_hw action, %d\n",
> err);
> - return err;
> + goto probe_err;
> }
> }
>
> @@ -533,7 +468,7 @@ static int tsc2007_probe(struct i2c_client *client,
> if (err) {
> dev_err(&client->dev, "Failed to request irq %d: %d\n",
> ts->irq, err);
> - return err;
> + goto probe_err;
> }
>
> tsc2007_stop(ts);
> @@ -543,17 +478,30 @@ 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 */
> + goto probe_err; /* chip does not respond */
> }
>
> err = input_register_device(input_dev);
> if (err) {
> dev_err(&client->dev,
> "Failed to register input device: %d\n", err);
> - return err;
> + goto probe_err;
> }
>
> return 0;
> +
> +probe_err:
> + tsc2007_iio_unconfigure(ts);
> + return err;
> +}
> +
> +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[] = {
> @@ -578,6 +526,7 @@ 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..0375d8b
> --- /dev/null
> +++ b/drivers/input/touchscreen/tsc2007_iio.c
> @@ -0,0 +1,151 @@
> +/*
> + * drivers/input/touchscreen/tsc2007_iio.c
> + *
> + * Copyright (c) 2016 Golden Delicious Comp. GmbH&Co. KG
> + * Nikolaus Schaller <hns@xxxxxxxxxxxxx>
> + *
> + * 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;
> +}
> +
> +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);
>