1 files changed, 583 insertions, 0 deletions

diff --git a/drivers/iio/adc/ad7606.c b/drivers/iio/adc/ad7606.c
new file mode 100644
index 000000000000..ebb8de03bbce
--- /dev/null
+++ b/drivers/iio/adc/ad7606.c
@@ -0,0 +1,583 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AD7606 SPI ADC driver
+ *
+ * Copyright 2011 Analog Devices Inc.
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/util_macros.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+
+#include "ad7606.h"
+
+/*
+ * Scales are computed as 5000/32768 and 10000/32768 respectively,
+ * so that when applied to the raw values they provide mV values
+ */
+static const unsigned int scale_avail[2] = {
+	152588, 305176
+};
+
+static const unsigned int ad7606_oversampling_avail[7] = {
+	1, 2, 4, 8, 16, 32, 64,
+};
+
+static int ad7606_reset(struct ad7606_state *st)
+{
+	if (st->gpio_reset) {
+		gpiod_set_value(st->gpio_reset, 1);
+		ndelay(100); /* t_reset >= 100ns */
+		gpiod_set_value(st->gpio_reset, 0);
+		return 0;
+	}
+
+	return -ENODEV;
+}
+
+static int ad7606_read_samples(struct ad7606_state *st)
+{
+	unsigned int num = st->chip_info->num_channels;
+	u16 *data = st->data;
+	int ret;
+
+	/*
+	 * The frstdata signal is set to high while and after reading the sample
+	 * of the first channel and low for all other channels. This can be used
+	 * to check that the incoming data is correctly aligned. During normal
+	 * operation the data should never become unaligned, but some glitch or
+	 * electrostatic discharge might cause an extra read or clock cycle.
+	 * Monitoring the frstdata signal allows to recover from such failure
+	 * situations.
+	 */
+
+	if (st->gpio_frstdata) {
+		ret = st->bops->read_block(st->dev, 1, data);
+		if (ret)
+			return ret;
+
+		if (!gpiod_get_value(st->gpio_frstdata)) {
+			ad7606_reset(st);
+			return -EIO;
+		}
+
+		data++;
+		num--;
+	}
+
+	return st->bops->read_block(st->dev, num, data);
+}
+
+static irqreturn_t ad7606_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct ad7606_state *st = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&st->lock);
+
+	ret = ad7606_read_samples(st);
+	if (ret == 0)
+		iio_push_to_buffers_with_timestamp(indio_dev, st->data,
+						   iio_get_time_ns(indio_dev));
+
+	iio_trigger_notify_done(indio_dev->trig);
+	/* The rising edge of the CONVST signal starts a new conversion. */
+	gpiod_set_value(st->gpio_convst, 1);
+
+	mutex_unlock(&st->lock);
+
+	return IRQ_HANDLED;
+}
+
+static int ad7606_scan_direct(struct iio_dev *indio_dev, unsigned int ch)
+{
+	struct ad7606_state *st = iio_priv(indio_dev);
+	int ret;
+
+	gpiod_set_value(st->gpio_convst, 1);
+	ret = wait_for_completion_timeout(&st->completion,
+					  msecs_to_jiffies(1000));
+	if (!ret) {
+		ret = -ETIMEDOUT;
+		goto error_ret;
+	}
+
+	ret = ad7606_read_samples(st);
+	if (ret == 0)
+		ret = st->data[ch];
+
+error_ret:
+	gpiod_set_value(st->gpio_convst, 0);
+
+	return ret;
+}
+
+static int ad7606_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val,
+			   int *val2,
+			   long m)
+{
+	int ret;
+	struct ad7606_state *st = iio_priv(indio_dev);
+
+	switch (m) {
+	case IIO_CHAN_INFO_RAW:
+		ret = iio_device_claim_direct_mode(indio_dev);
+		if (ret)
+			return ret;
+
+		ret = ad7606_scan_direct(indio_dev, chan->address);
+		iio_device_release_direct_mode(indio_dev);
+
+		if (ret < 0)
+			return ret;
+		*val = (short)ret;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = 0;
+		*val2 = scale_avail[st->range];
+		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		*val = st->oversampling;
+		return IIO_VAL_INT;
+	}
+	return -EINVAL;
+}
+
+static ssize_t in_voltage_scale_available_show(struct device *dev,
+					       struct device_attribute *attr,
+					       char *buf)
+{
+	int i, len = 0;
+
+	for (i = 0; i < ARRAY_SIZE(scale_avail); i++)
+		len += scnprintf(buf + len, PAGE_SIZE - len, "0.%06u ",
+				 scale_avail[i]);
+
+	buf[len - 1] = '\n';
+
+	return len;
+}
+
+static IIO_DEVICE_ATTR_RO(in_voltage_scale_available, 0);
+
+static int ad7606_write_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int val,
+			    int val2,
+			    long mask)
+{
+	struct ad7606_state *st = iio_priv(indio_dev);
+	DECLARE_BITMAP(values, 3);
+	int i;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		mutex_lock(&st->lock);
+		i = find_closest(val2, scale_avail, ARRAY_SIZE(scale_avail));
+		gpiod_set_value(st->gpio_range, i);
+		st->range = i;
+		mutex_unlock(&st->lock);
+
+		return 0;
+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		if (val2)
+			return -EINVAL;
+		i = find_closest(val, ad7606_oversampling_avail,
+				 ARRAY_SIZE(ad7606_oversampling_avail));
+
+		values[0] = i;
+
+		mutex_lock(&st->lock);
+		gpiod_set_array_value(ARRAY_SIZE(values), st->gpio_os->desc,
+				      st->gpio_os->info, values);
+		st->oversampling = ad7606_oversampling_avail[i];
+		mutex_unlock(&st->lock);
+
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+static IIO_CONST_ATTR(oversampling_ratio_available, "1 2 4 8 16 32 64");
+
+static struct attribute *ad7606_attributes_os_and_range[] = {
+	&iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
+	&iio_const_attr_oversampling_ratio_available.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ad7606_attribute_group_os_and_range = {
+	.attrs = ad7606_attributes_os_and_range,
+};
+
+static struct attribute *ad7606_attributes_os[] = {
+	&iio_const_attr_oversampling_ratio_available.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ad7606_attribute_group_os = {
+	.attrs = ad7606_attributes_os,
+};
+
+static struct attribute *ad7606_attributes_range[] = {
+	&iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ad7606_attribute_group_range = {
+	.attrs = ad7606_attributes_range,
+};
+
+#define AD760X_CHANNEL(num, mask) {				\
+		.type = IIO_VOLTAGE,				\
+		.indexed = 1,					\
+		.channel = num,					\
+		.address = num,					\
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\
+		.info_mask_shared_by_all = mask,		\
+		.scan_index = num,				\
+		.scan_type = {					\
+			.sign = 's',				\
+			.realbits = 16,				\
+			.storagebits = 16,			\
+			.endianness = IIO_CPU,			\
+		},						\
+}
+
+#define AD7605_CHANNEL(num)	\
+	AD760X_CHANNEL(num, 0)
+
+#define AD7606_CHANNEL(num)	\
+	AD760X_CHANNEL(num, BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO))
+
+static const struct iio_chan_spec ad7605_channels[] = {
+	IIO_CHAN_SOFT_TIMESTAMP(4),
+	AD7605_CHANNEL(0),
+	AD7605_CHANNEL(1),
+	AD7605_CHANNEL(2),
+	AD7605_CHANNEL(3),
+};
+
+static const struct iio_chan_spec ad7606_channels[] = {
+	IIO_CHAN_SOFT_TIMESTAMP(8),
+	AD7606_CHANNEL(0),
+	AD7606_CHANNEL(1),
+	AD7606_CHANNEL(2),
+	AD7606_CHANNEL(3),
+	AD7606_CHANNEL(4),
+	AD7606_CHANNEL(5),
+	AD7606_CHANNEL(6),
+	AD7606_CHANNEL(7),
+};
+
+static const struct ad7606_chip_info ad7606_chip_info_tbl[] = {
+	/* More devices added in future */
+	[ID_AD7605_4] = {
+		.channels = ad7605_channels,
+		.num_channels = 5,
+	},
+	[ID_AD7606_8] = {
+		.channels = ad7606_channels,
+		.num_channels = 9,
+		.has_oversampling = true,
+	},
+	[ID_AD7606_6] = {
+		.channels = ad7606_channels,
+		.num_channels = 7,
+		.has_oversampling = true,
+	},
+	[ID_AD7606_4] = {
+		.channels = ad7606_channels,
+		.num_channels = 5,
+		.has_oversampling = true,
+	},
+};
+
+static int ad7606_request_gpios(struct ad7606_state *st)
+{
+	struct device *dev = st->dev;
+
+	st->gpio_convst = devm_gpiod_get(dev, "adi,conversion-start",
+					 GPIOD_OUT_LOW);
+	if (IS_ERR(st->gpio_convst))
+		return PTR_ERR(st->gpio_convst);
+
+	st->gpio_reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(st->gpio_reset))
+		return PTR_ERR(st->gpio_reset);
+
+	st->gpio_range = devm_gpiod_get_optional(dev, "adi,range",
+						 GPIOD_OUT_LOW);
+	if (IS_ERR(st->gpio_range))
+		return PTR_ERR(st->gpio_range);
+
+	st->gpio_standby = devm_gpiod_get_optional(dev, "standby",
+						   GPIOD_OUT_HIGH);
+	if (IS_ERR(st->gpio_standby))
+		return PTR_ERR(st->gpio_standby);
+
+	st->gpio_frstdata = devm_gpiod_get_optional(dev, "adi,first-data",
+						    GPIOD_IN);
+	if (IS_ERR(st->gpio_frstdata))
+		return PTR_ERR(st->gpio_frstdata);
+
+	if (!st->chip_info->has_oversampling)
+		return 0;
+
+	st->gpio_os = devm_gpiod_get_array_optional(dev,
+						    "adi,oversampling-ratio",
+						    GPIOD_OUT_LOW);
+	return PTR_ERR_OR_ZERO(st->gpio_os);
+}
+
+/*
+ * The BUSY signal indicates when conversions are in progress, so when a rising
+ * edge of CONVST is applied, BUSY goes logic high and transitions low at the
+ * end of the entire conversion process. The falling edge of the BUSY signal
+ * triggers this interrupt.
+ */
+static irqreturn_t ad7606_interrupt(int irq, void *dev_id)
+{
+	struct iio_dev *indio_dev = dev_id;
+	struct ad7606_state *st = iio_priv(indio_dev);
+
+	if (iio_buffer_enabled(indio_dev)) {
+		gpiod_set_value(st->gpio_convst, 0);
+		iio_trigger_poll_chained(st->trig);
+	} else {
+		complete(&st->completion);
+	}
+
+	return IRQ_HANDLED;
+};
+
+static int ad7606_validate_trigger(struct iio_dev *indio_dev,
+				   struct iio_trigger *trig)
+{
+	struct ad7606_state *st = iio_priv(indio_dev);
+
+	if (st->trig != trig)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int ad7606_buffer_postenable(struct iio_dev *indio_dev)
+{
+	struct ad7606_state *st = iio_priv(indio_dev);
+
+	iio_triggered_buffer_postenable(indio_dev);
+	gpiod_set_value(st->gpio_convst, 1);
+
+	return 0;
+}
+
+static int ad7606_buffer_predisable(struct iio_dev *indio_dev)
+{
+	struct ad7606_state *st = iio_priv(indio_dev);
+
+	gpiod_set_value(st->gpio_convst, 0);
+
+	return iio_triggered_buffer_predisable(indio_dev);
+}
+
+static const struct iio_buffer_setup_ops ad7606_buffer_ops = {
+	.postenable = &ad7606_buffer_postenable,
+	.predisable = &ad7606_buffer_predisable,
+};
+
+static const struct iio_info ad7606_info_no_os_or_range = {
+	.read_raw = &ad7606_read_raw,
+	.validate_trigger = &ad7606_validate_trigger,
+};
+
+static const struct iio_info ad7606_info_os_and_range = {
+	.read_raw = &ad7606_read_raw,
+	.write_raw = &ad7606_write_raw,
+	.attrs = &ad7606_attribute_group_os_and_range,
+	.validate_trigger = &ad7606_validate_trigger,
+};
+
+static const struct iio_info ad7606_info_os = {
+	.read_raw = &ad7606_read_raw,
+	.write_raw = &ad7606_write_raw,
+	.attrs = &ad7606_attribute_group_os,
+	.validate_trigger = &ad7606_validate_trigger,
+};
+
+static const struct iio_info ad7606_info_range = {
+	.read_raw = &ad7606_read_raw,
+	.write_raw = &ad7606_write_raw,
+	.attrs = &ad7606_attribute_group_range,
+	.validate_trigger = &ad7606_validate_trigger,
+};
+
+static const struct iio_trigger_ops ad7606_trigger_ops = {
+	.validate_device = iio_trigger_validate_own_device,
+};
+
+static void ad7606_regulator_disable(void *data)
+{
+	struct ad7606_state *st = data;
+
+	regulator_disable(st->reg);
+}
+
+int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
+		 const char *name, unsigned int id,
+		 const struct ad7606_bus_ops *bops)
+{
+	struct ad7606_state *st;
+	int ret;
+	struct iio_dev *indio_dev;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	st = iio_priv(indio_dev);
+	dev_set_drvdata(dev, indio_dev);
+
+	st->dev = dev;
+	mutex_init(&st->lock);
+	st->bops = bops;
+	st->base_address = base_address;
+	/* tied to logic low, analog input range is +/- 5V */
+	st->range = 0;
+	st->oversampling = 1;
+
+	st->reg = devm_regulator_get(dev, "avcc");
+	if (IS_ERR(st->reg))
+		return PTR_ERR(st->reg);
+
+	ret = regulator_enable(st->reg);
+	if (ret) {
+		dev_err(dev, "Failed to enable specified AVcc supply\n");
+		return ret;
+	}
+
+	ret = devm_add_action_or_reset(dev, ad7606_regulator_disable, st);
+	if (ret)
+		return ret;
+
+	st->chip_info = &ad7606_chip_info_tbl[id];
+
+	ret = ad7606_request_gpios(st);
+	if (ret)
+		return ret;
+
+	indio_dev->dev.parent = dev;
+	if (st->gpio_os) {
+		if (st->gpio_range)
+			indio_dev->info = &ad7606_info_os_and_range;
+		else
+			indio_dev->info = &ad7606_info_os;
+	} else {
+		if (st->gpio_range)
+			indio_dev->info = &ad7606_info_range;
+		else
+			indio_dev->info = &ad7606_info_no_os_or_range;
+	}
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->name = name;
+	indio_dev->channels = st->chip_info->channels;
+	indio_dev->num_channels = st->chip_info->num_channels;
+
+	init_completion(&st->completion);
+
+	ret = ad7606_reset(st);
+	if (ret)
+		dev_warn(st->dev, "failed to RESET: no RESET GPIO specified\n");
+
+	st->trig = devm_iio_trigger_alloc(dev, "%s-dev%d",
+					  indio_dev->name, indio_dev->id);
+	if (!st->trig)
+		return -ENOMEM;
+
+	st->trig->ops = &ad7606_trigger_ops;
+	st->trig->dev.parent = dev;
+	iio_trigger_set_drvdata(st->trig, indio_dev);
+	ret = devm_iio_trigger_register(dev, st->trig);
+	if (ret)
+		return ret;
+
+	indio_dev->trig = iio_trigger_get(st->trig);
+
+	ret = devm_request_threaded_irq(dev, irq,
+					NULL,
+					&ad7606_interrupt,
+					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+					name, indio_dev);
+	if (ret)
+		return ret;
+
+	ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
+					      &iio_pollfunc_store_time,
+					      &ad7606_trigger_handler,
+					      &ad7606_buffer_ops);
+	if (ret)
+		return ret;
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+EXPORT_SYMBOL_GPL(ad7606_probe);
+
+#ifdef CONFIG_PM_SLEEP
+
+static int ad7606_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad7606_state *st = iio_priv(indio_dev);
+
+	if (st->gpio_standby) {
+		gpiod_set_value(st->gpio_range, 1);
+		gpiod_set_value(st->gpio_standby, 0);
+	}
+
+	return 0;
+}
+
+static int ad7606_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad7606_state *st = iio_priv(indio_dev);
+
+	if (st->gpio_standby) {
+		gpiod_set_value(st->gpio_range, st->range);
+		gpiod_set_value(st->gpio_standby, 1);
+		ad7606_reset(st);
+	}
+
+	return 0;
+}
+
+SIMPLE_DEV_PM_OPS(ad7606_pm_ops, ad7606_suspend, ad7606_resume);
+EXPORT_SYMBOL_GPL(ad7606_pm_ops);
+
+#endif
+
+MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD7606 ADC");
+MODULE_LICENSE("GPL v2");