Merge tag 'iio-for-4.19a' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-next

Jonathan writes:

First set of IIO new device support, features and cleanups in the 4.19 cycle

The usual mixed bunch.  Particular good to see is the generic
touch screen driver.  Will be interesting to see if this works
for other ADCs without major changes.

Core features
* Channel types
  - New position relative channel type primarily for touch screen
    sensors to feed the generic touchscreen driver.

New device support
* ad5586
  - Add support for the AD5311R DAC.

* Generic touch screen driver as an IIO consumer.
  - Note this is in input, but due to dependencies is coming through
    the IIO tree.
  - Specific support for this added to the at91-sama5d2 ADC.
  - Various necessary DT bindings added.

Staging Drops
* ADIS16060 gyro
  - A device with a very odd interface that was never cleanly supported.
    It's now very difficult to get, so unlikely it'll ever be fixed up.

Cleanups and minor features and fixes
* core
  - Fix y2038 timestamp issues now the core support is in place.
* 104-quad-8
  - Provide some defines for magic numbers to help readability.
  - Fix an off by one error in register selection
* ad7606
  - Put in a missing function parameter name in a prototype.
* adis16023
  - Use generic sign_extend function rather than local version.
* adis16240
  - Use generic sign_extend funciton rather than local version.
* at91-sama5d2
  - Drop dependency on HAS_DMA now this is handled elsewhere.  Will
    improve build test coverage.
  - Add oversampling ratio control.  Note there is a minor ABI change
    here to increase the apparent depth to 14 bits so as to allow
    for transparent provision of different oversampling ratios that
    drop the actual bit depth to 13 or 12 bits.
* hx711
  - Add a MAINTAINERS entry for this device.
* inv_mpu6050
  - Replace the timestamp fifo 'special' code with generic timestamp
    handling.
  - Switch to using local store of timestamp divider rather than rate
    as that is more helpful for accurate time measurement.
  - Fix an unaligned access that didn't seem to be causing any trouble.
  - Use the fifo overflow bit to track the overflow status rather than
    a software counter.
  - New timestamping mechanism to deal with missed sample interrupts.
* stm32-adc
  - Drop HAS_DMA build dependency.
* sun4i-gpadc
  - Select REGMAP_IRQ a very rarely hit build issue fix.

3 files changed, 218 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 32267c1afebc..66d1a220726a 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -92,6 +92,19 @@ config TOUCHSCREEN_AD7879_SPI
 	  To compile this driver as a module, choose M here: the
 	  module will be called ad7879-spi.
 
+config TOUCHSCREEN_ADC
+	tristate "Generic ADC based resistive touchscreen"
+	depends on IIO
+	select IIO_BUFFER_CB
+	help
+	  Say Y here if you want to use the generic ADC
+	  resistive touchscreen driver.
+
+	  If unsure, say N (but it's safe to say "Y").
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called resistive-adc-touch.ko.
+
 config TOUCHSCREEN_AR1021_I2C
 	tristate "Microchip AR1020/1021 i2c touchscreen"
 	depends on I2C && OF
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index fd4fd32fb73f..35bd0619edf1 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_TOUCHSCREEN_AD7877)	+= ad7877.o
 obj-$(CONFIG_TOUCHSCREEN_AD7879)	+= ad7879.o
 obj-$(CONFIG_TOUCHSCREEN_AD7879_I2C)	+= ad7879-i2c.o
 obj-$(CONFIG_TOUCHSCREEN_AD7879_SPI)	+= ad7879-spi.o
+obj-$(CONFIG_TOUCHSCREEN_ADC)		+= resistive-adc-touch.o
 obj-$(CONFIG_TOUCHSCREEN_ADS7846)	+= ads7846.o
 obj-$(CONFIG_TOUCHSCREEN_AR1021_I2C)	+= ar1021_i2c.o
 obj-$(CONFIG_TOUCHSCREEN_ATMEL_MXT)	+= atmel_mxt_ts.o
diff --git a/drivers/input/touchscreen/resistive-adc-touch.c b/drivers/input/touchscreen/resistive-adc-touch.c
new file mode 100644
index 000000000000..cfc8bb4553f7
--- /dev/null
+++ b/drivers/input/touchscreen/resistive-adc-touch.c
@@ -0,0 +1,204 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ADC generic resistive touchscreen (GRTS)
+ * This is a generic input driver that connects to an ADC
+ * given the channels in device tree, and reports events to the input
+ * subsystem.
+ *
+ * Copyright (C) 2017,2018 Microchip Technology,
+ * Author: Eugen Hristev <eugen.hristev@microchip.com>
+ *
+ */
+#include <linux/input.h>
+#include <linux/input/touchscreen.h>
+#include <linux/iio/consumer.h>
+#include <linux/iio/iio.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+
+#define DRIVER_NAME					"resistive-adc-touch"
+#define GRTS_DEFAULT_PRESSURE_MIN			50000
+#define GRTS_MAX_POS_MASK				GENMASK(11, 0)
+
+/**
+ * grts_state - generic resistive touch screen information struct
+ * @pressure_min:	number representing the minimum for the pressure
+ * @pressure:		are we getting pressure info or not
+ * @iio_chans:		list of channels acquired
+ * @iio_cb:		iio_callback buffer for the data
+ * @input:		the input device structure that we register
+ * @prop:		touchscreen properties struct
+ */
+struct grts_state {
+	u32				pressure_min;
+	bool				pressure;
+	struct iio_channel		*iio_chans;
+	struct iio_cb_buffer		*iio_cb;
+	struct input_dev		*input;
+	struct touchscreen_properties	prop;
+};
+
+static int grts_cb(const void *data, void *private)
+{
+	const u16 *touch_info = data;
+	struct grts_state *st = private;
+	unsigned int x, y, press = 0x0;
+
+	/* channel data coming in buffer in the order below */
+	x = touch_info[0];
+	y = touch_info[1];
+	if (st->pressure)
+		press = touch_info[2];
+
+	if ((!x && !y) || (st->pressure && (press < st->pressure_min))) {
+		/* report end of touch */
+		input_report_key(st->input, BTN_TOUCH, 0);
+		input_sync(st->input);
+		return 0;
+	}
+
+	/* report proper touch to subsystem*/
+	touchscreen_report_pos(st->input, &st->prop, x, y, false);
+	if (st->pressure)
+		input_report_abs(st->input, ABS_PRESSURE, press);
+	input_report_key(st->input, BTN_TOUCH, 1);
+	input_sync(st->input);
+
+	return 0;
+}
+
+static int grts_open(struct input_dev *dev)
+{
+	int error;
+	struct grts_state *st = input_get_drvdata(dev);
+
+	error = iio_channel_start_all_cb(st->iio_cb);
+	if (error) {
+		dev_err(dev->dev.parent, "failed to start callback buffer.\n");
+		return error;
+	}
+	return 0;
+}
+
+static void grts_close(struct input_dev *dev)
+{
+	struct grts_state *st = input_get_drvdata(dev);
+
+	iio_channel_stop_all_cb(st->iio_cb);
+}
+
+static void grts_disable(void *data)
+{
+	iio_channel_release_all_cb(data);
+}
+
+static int grts_probe(struct platform_device *pdev)
+{
+	struct grts_state *st;
+	struct input_dev *input;
+	struct device *dev = &pdev->dev;
+	struct iio_channel *chan;
+	int error;
+
+	st = devm_kzalloc(dev, sizeof(struct grts_state), GFP_KERNEL);
+	if (!st)
+		return -ENOMEM;
+
+	/* get the channels from IIO device */
+	st->iio_chans = devm_iio_channel_get_all(dev);
+	if (IS_ERR(st->iio_chans)) {
+		error = PTR_ERR(st->iio_chans);
+		if (error != -EPROBE_DEFER)
+			dev_err(dev, "can't get iio channels.\n");
+		return error;
+	}
+
+	chan = &st->iio_chans[0];
+	st->pressure = false;
+	while (chan && chan->indio_dev) {
+		if (!strcmp(chan->channel->datasheet_name, "pressure"))
+			st->pressure = true;
+		chan++;
+	}
+
+	if (st->pressure) {
+		error = device_property_read_u32(dev,
+						 "touchscreen-min-pressure",
+						 &st->pressure_min);
+		if (error) {
+			dev_dbg(dev, "can't get touchscreen-min-pressure property.\n");
+			st->pressure_min = GRTS_DEFAULT_PRESSURE_MIN;
+		}
+	}
+
+	input = devm_input_allocate_device(dev);
+	if (!input) {
+		dev_err(dev, "failed to allocate input device.\n");
+		return -ENOMEM;
+	}
+
+	input->name = DRIVER_NAME;
+	input->id.bustype = BUS_HOST;
+	input->open = grts_open;
+	input->close = grts_close;
+
+	input_set_abs_params(input, ABS_X, 0, GRTS_MAX_POS_MASK - 1, 0, 0);
+	input_set_abs_params(input, ABS_Y, 0, GRTS_MAX_POS_MASK - 1, 0, 0);
+	if (st->pressure)
+		input_set_abs_params(input, ABS_PRESSURE, st->pressure_min,
+				     0xffff, 0, 0);
+
+	input_set_capability(input, EV_KEY, BTN_TOUCH);
+
+	/* parse optional device tree properties */
+	touchscreen_parse_properties(input, false, &st->prop);
+
+	st->input = input;
+	input_set_drvdata(input, st);
+
+	error = input_register_device(input);
+	if (error) {
+		dev_err(dev, "failed to register input device.");
+		return error;
+	}
+
+	st->iio_cb = iio_channel_get_all_cb(dev, grts_cb, st);
+	if (IS_ERR(st->iio_cb)) {
+		dev_err(dev, "failed to allocate callback buffer.\n");
+		return PTR_ERR(st->iio_cb);
+	}
+
+	error = devm_add_action_or_reset(dev, grts_disable, st->iio_cb);
+	if (error) {
+		dev_err(dev, "failed to add disable action.\n");
+		return error;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id grts_of_match[] = {
+	{
+		.compatible = "resistive-adc-touch",
+	}, {
+		/* sentinel */
+	},
+};
+
+MODULE_DEVICE_TABLE(of, grts_of_match);
+
+static struct platform_driver grts_driver = {
+	.probe = grts_probe,
+	.driver = {
+		.name = DRIVER_NAME,
+		.of_match_table = of_match_ptr(grts_of_match),
+	},
+};
+
+module_platform_driver(grts_driver);
+
+MODULE_AUTHOR("Eugen Hristev <eugen.hristev@microchip.com>");
+MODULE_DESCRIPTION("Generic ADC Resistive Touch Driver");
+MODULE_LICENSE("GPL v2");