Message-ID: <E42B1EF7-222E-46D6-878B-30C789CFBBC5@jic23.retrosnub.co.uk>
Date:   Thu, 24 Nov 2016 17:38:05 +0000
From:   Jonathan Cameron <jic23@...23.retrosnub.co.uk>
To:     "H. Nikolaus Schaller" <hns@...delico.com>,
        Sebastian Reichel <sre@...nel.org>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Mark Rutland <mark.rutland@....com>,
        Benoît Cousson <bcousson@...libre.com>,
        Tony Lindgren <tony@...mide.com>,
        Russell King <linux@...linux.org.uk>,
        Arnd Bergmann <arnd@...db.de>,
        Michael Welling <mwelling@...e.org>,
        Mika Penttilä <mika.penttila@...tfour.com>,
        Javier Martinez Canillas <javier@....samsung.com>,
        Igor Grinberg <grinberg@...pulab.co.il>,
        "Andrew F. Davis" <afd@...com>, Mark Brown <broonie@...nel.org>,
        Jonathan Cameron <jic23@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Alexander Stein <alexander.stein@...tec-electronic.com>,
        Eric Engestrom <eric@...estrom.ch>,
        Hans de Goede <hdegoede@...hat.com>,
        Benjamin Tissoires <benjamin.tissoires@...hat.com>,
        Denis Carikli <denis@...rea.com>, Petr Cvek <petr.cvek@....cz>
CC:     linux-input@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-omap@...r.kernel.org,
        letux-kernel@...nphoenux.org, linux-iio@...r.kernel.org,
        kernel@...a-handheld.com
Subject: Re: [PATCH v8 3/8] drivers:input:tsc2007: add iio interface to read external ADC input and temperature



On 22 November 2016 14:02:30 GMT+00:00, "H. Nikolaus Schaller" <hns@...delico.com> 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@...delico.com>
>Reviewed-by: Jonathan Cameron <jic23@...nel.org>
>---
> drivers/input/touchscreen/Makefile                 |   7 +
>drivers/input/touchscreen/tsc2007.h                | 116
>++++++++++++++++
> .../touchscreen/{tsc2007.c => tsc2007_core.c}      |  95 +++----------
>drivers/input/touchscreen/tsc2007_iio.c            | 150
>+++++++++++++++++++++
> 4 files changed, 294 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/Makefile
>b/drivers/input/touchscreen/Makefile
>index 81b8645..3be0d19 100644
>--- a/drivers/input/touchscreen/Makefile
>+++ b/drivers/input/touchscreen/Makefile
>@@ -80,6 +80,13 @@ 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
>+ifeq ($(CONFIG_IIO),y)
>+tsc2007-y				+= tsc2007_iio.o
>+endif
>+ifeq ($(CONFIG_IIO),m)
>+tsc2007-y				+= tsc2007_iio.o

Not tsc2007-m ?

I don't follow how this works!
>+endif
> 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..c25932f
>--- /dev/null
>+++ b/drivers/input/touchscreen/tsc2007.h
>@@ -0,0 +1,116 @@
>+/*
>+ * Copyright (c) 2008 MtekVision Co., Ltd.
>+ *	Kwangwoo Lee <kwlee@...kvision.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_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 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,
>+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@...delico.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);
>+	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->iio_dev;
>+
>+	iio_device_unregister(indio_dev);
>+}
>+EXPORT_SYMBOL(tsc2007_iio_unconfigure);

-- 
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