staging: IIO: ADC: New driver for AD7606/AD7606-6/AD7606-4

This patch adds support for the:
AD7606/AD7606-6/AD7606-4 8/6/4-Channel Data Acquisition
system (DAS) with 16-Bit, Bipolar, Simultaneous Sampling ADC.

Changes since V1:
IIO: ADC: New driver for AD7606/AD7606-6/AD7606-4: Apply review feedback

Rename sysfs node oversampling to oversampling_ratio.
Kconfig: Add GPIOLIB dependency.
Use range in mV to better match HWMON.
Rename ad7606_check_oversampling.
Fix various comments and style.
Reorder is_visible cases.
Use new gpio_request_one/array and friends.
Drop check for SPI max_speed_hz.

Changes since V2:
IIO: ADC: New driver for AD7606/AD7606-6/AD7606-4: Apply review feedback

Documentation: specify unit
Avoid raise condition in ad7606_scan_direct()
Check return value of bus ops read_block()

Changes since V3:
IIO: ADC: New driver for AD7606/AD7606-6/AD7606-4: Add missing include file

Add linux/sched.h

Changes since V4:
IIO: ADC: New driver for AD7606/AD7606-6/AD7606-4: Fix kconfig declaration

consistently use tristate to avoid configuration mismatches

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 556 insertions, 0 deletions

diff --git a/drivers/staging/iio/adc/ad7606_core.c b/drivers/staging/iio/adc/ad7606_core.c
new file mode 100644
index 000000000000..4c700f07fb83
--- /dev/null
+++ b/drivers/staging/iio/adc/ad7606_core.c
@@ -0,0 +1,556 @@
+/*
+ * AD7606 SPI ADC driver
+ *
+ * Copyright 2011 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/workqueue.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/list.h>
+#include <linux/regulator/consumer.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/delay.h>
+#include <linux/sched.h>
+
+#include "../iio.h"
+#include "../sysfs.h"
+#include "../ring_generic.h"
+#include "adc.h"
+
+#include "ad7606.h"
+
+int ad7606_reset(struct ad7606_state *st)
+{
+	if (st->have_reset) {
+		gpio_set_value(st->pdata->gpio_reset, 1);
+		ndelay(100); /* t_reset >= 100ns */
+		gpio_set_value(st->pdata->gpio_reset, 0);
+		return 0;
+	}
+
+	return -ENODEV;
+}
+
+static int ad7606_scan_direct(struct ad7606_state *st, unsigned ch)
+{
+	int ret;
+
+	st->done = false;
+	gpio_set_value(st->pdata->gpio_convst, 1);
+
+	ret = wait_event_interruptible(st->wq_data_avail, st->done);
+	if (ret)
+		goto error_ret;
+
+	if (st->have_frstdata) {
+		ret = st->bops->read_block(st->dev, 1, st->data);
+		if (ret)
+			goto error_ret;
+		if (!gpio_get_value(st->pdata->gpio_frstdata)) {
+			/* This should never happen */
+			ad7606_reset(st);
+			ret = -EIO;
+			goto error_ret;
+		}
+		ret = st->bops->read_block(st->dev,
+			st->chip_info->num_channels - 1, &st->data[1]);
+		if (ret)
+			goto error_ret;
+	} else {
+		ret = st->bops->read_block(st->dev,
+			st->chip_info->num_channels, st->data);
+		if (ret)
+			goto error_ret;
+	}
+
+	ret = st->data[ch];
+
+error_ret:
+	gpio_set_value(st->pdata->gpio_convst, 0);
+
+	return ret;
+}
+
+static ssize_t ad7606_scan(struct device *dev,
+			    struct device_attribute *attr,
+			    char *buf)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7606_state *st = dev_info->dev_data;
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	int ret;
+
+	mutex_lock(&dev_info->mlock);
+	if (iio_ring_enabled(dev_info))
+		ret = ad7606_scan_from_ring(st, this_attr->address);
+	else
+		ret = ad7606_scan_direct(st, this_attr->address);
+	mutex_unlock(&dev_info->mlock);
+
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%d\n", (short) ret);
+}
+
+static IIO_DEV_ATTR_IN_RAW(0, ad7606_scan, 0);
+static IIO_DEV_ATTR_IN_RAW(1, ad7606_scan, 1);
+static IIO_DEV_ATTR_IN_RAW(2, ad7606_scan, 2);
+static IIO_DEV_ATTR_IN_RAW(3, ad7606_scan, 3);
+static IIO_DEV_ATTR_IN_RAW(4, ad7606_scan, 4);
+static IIO_DEV_ATTR_IN_RAW(5, ad7606_scan, 5);
+static IIO_DEV_ATTR_IN_RAW(6, ad7606_scan, 6);
+static IIO_DEV_ATTR_IN_RAW(7, ad7606_scan, 7);
+
+static ssize_t ad7606_show_scale(struct device *dev,
+				struct device_attribute *attr,
+				char *buf)
+{
+	/* Driver currently only support internal vref */
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7606_state *st = iio_dev_get_devdata(dev_info);
+	unsigned int scale_uv = (st->range * 1000 * 2) >> st->chip_info->bits;
+
+	return sprintf(buf, "%d.%03d\n", scale_uv / 1000, scale_uv % 1000);
+}
+static IIO_DEVICE_ATTR(in_scale, S_IRUGO, ad7606_show_scale, NULL, 0);
+
+static ssize_t ad7606_show_name(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7606_state *st = iio_dev_get_devdata(dev_info);
+
+	return sprintf(buf, "%s\n", st->chip_info->name);
+}
+
+static IIO_DEVICE_ATTR(name, S_IRUGO, ad7606_show_name, NULL, 0);
+
+static ssize_t ad7606_show_range(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7606_state *st = iio_dev_get_devdata(dev_info);
+
+	return sprintf(buf, "%u\n", st->range);
+}
+
+static ssize_t ad7606_store_range(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7606_state *st = iio_dev_get_devdata(dev_info);
+	unsigned long lval;
+
+	if (strict_strtoul(buf, 10, &lval))
+		return -EINVAL;
+	if (!(lval == 5000 || lval == 10000)) {
+		dev_err(dev, "range is not supported\n");
+		return -EINVAL;
+	}
+	mutex_lock(&dev_info->mlock);
+	gpio_set_value(st->pdata->gpio_range, lval == 10000);
+	st->range = lval;
+	mutex_unlock(&dev_info->mlock);
+
+	return count;
+}
+
+static IIO_DEVICE_ATTR(range, S_IRUGO | S_IWUSR, \
+		       ad7606_show_range, ad7606_store_range, 0);
+static IIO_CONST_ATTR(range_available, "5000 10000");
+
+static ssize_t ad7606_show_oversampling_ratio(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7606_state *st = iio_dev_get_devdata(dev_info);
+
+	return sprintf(buf, "%u\n", st->oversampling);
+}
+
+static int ad7606_oversampling_get_index(unsigned val)
+{
+	unsigned char supported[] = {0, 2, 4, 8, 16, 32, 64};
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(supported); i++)
+		if (val == supported[i])
+			return i;
+
+	return -EINVAL;
+}
+
+static ssize_t ad7606_store_oversampling_ratio(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7606_state *st = iio_dev_get_devdata(dev_info);
+	unsigned long lval;
+	int ret;
+
+	if (strict_strtoul(buf, 10, &lval))
+		return -EINVAL;
+
+	ret = ad7606_oversampling_get_index(lval);
+	if (ret < 0) {
+		dev_err(dev, "oversampling %lu is not supported\n", lval);
+		return ret;
+	}
+
+	mutex_lock(&dev_info->mlock);
+	gpio_set_value(st->pdata->gpio_os0, (ret >> 0) & 1);
+	gpio_set_value(st->pdata->gpio_os1, (ret >> 1) & 1);
+	gpio_set_value(st->pdata->gpio_os1, (ret >> 2) & 1);
+	st->oversampling = lval;
+	mutex_unlock(&dev_info->mlock);
+
+	return count;
+}
+
+static IIO_DEVICE_ATTR(oversampling_ratio, S_IRUGO | S_IWUSR,
+		       ad7606_show_oversampling_ratio,
+		       ad7606_store_oversampling_ratio, 0);
+static IIO_CONST_ATTR(oversampling_ratio_available, "0 2 4 8 16 32 64");
+
+static struct attribute *ad7606_attributes[] = {
+	&iio_dev_attr_in0_raw.dev_attr.attr,
+	&iio_dev_attr_in1_raw.dev_attr.attr,
+	&iio_dev_attr_in2_raw.dev_attr.attr,
+	&iio_dev_attr_in3_raw.dev_attr.attr,
+	&iio_dev_attr_in4_raw.dev_attr.attr,
+	&iio_dev_attr_in5_raw.dev_attr.attr,
+	&iio_dev_attr_in6_raw.dev_attr.attr,
+	&iio_dev_attr_in7_raw.dev_attr.attr,
+	&iio_dev_attr_in_scale.dev_attr.attr,
+	&iio_dev_attr_name.dev_attr.attr,
+	&iio_dev_attr_range.dev_attr.attr,
+	&iio_const_attr_range_available.dev_attr.attr,
+	&iio_dev_attr_oversampling_ratio.dev_attr.attr,
+	&iio_const_attr_oversampling_ratio_available.dev_attr.attr,
+	NULL,
+};
+
+static mode_t ad7606_attr_is_visible(struct kobject *kobj,
+				     struct attribute *attr, int n)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7606_state *st = iio_dev_get_devdata(dev_info);
+
+	mode_t mode = attr->mode;
+
+	if (st->chip_info->num_channels <= 6 &&
+		(attr == &iio_dev_attr_in7_raw.dev_attr.attr ||
+		attr == &iio_dev_attr_in6_raw.dev_attr.attr))
+		mode = 0;
+	else if (st->chip_info->num_channels <= 4 &&
+		(attr == &iio_dev_attr_in5_raw.dev_attr.attr ||
+		attr == &iio_dev_attr_in4_raw.dev_attr.attr))
+		mode = 0;
+	else if (!st->have_os &&
+		(attr == &iio_dev_attr_oversampling_ratio.dev_attr.attr ||
+		attr ==
+		&iio_const_attr_oversampling_ratio_available.dev_attr.attr))
+		mode = 0;
+	else if (!st->have_range &&
+		(attr == &iio_dev_attr_range.dev_attr.attr ||
+		attr == &iio_const_attr_range_available.dev_attr.attr))
+			mode = 0;
+
+	return mode;
+}
+
+static const struct attribute_group ad7606_attribute_group = {
+	.attrs = ad7606_attributes,
+	.is_visible = ad7606_attr_is_visible,
+};
+
+static const struct ad7606_chip_info ad7606_chip_info_tbl[] = {
+	/*
+	 * More devices added in future
+	 */
+	[ID_AD7606_8] = {
+		.name = "ad7606",
+		.bits = 16,
+		.sign = IIO_SCAN_EL_TYPE_SIGNED,
+		.int_vref_mv = 2500,
+		.num_channels = 8,
+	},
+	[ID_AD7606_6] = {
+		.name = "ad7606-6",
+		.bits = 16,
+		.sign = IIO_SCAN_EL_TYPE_SIGNED,
+		.int_vref_mv = 2500,
+		.num_channels = 6,
+	},
+	[ID_AD7606_4] = {
+		.name = "ad7606-4",
+		.bits = 16,
+		.sign = IIO_SCAN_EL_TYPE_SIGNED,
+		.int_vref_mv = 2500,
+		.num_channels = 4,
+	},
+};
+
+static int ad7606_request_gpios(struct ad7606_state *st)
+{
+	struct gpio gpio_array[3] = {
+		[0] = {
+			.gpio =  st->pdata->gpio_os0,
+			.flags = GPIOF_DIR_OUT | ((st->oversampling & 1) ?
+				 GPIOF_INIT_HIGH : GPIOF_INIT_LOW),
+			.label = "AD7606_OS0",
+		},
+		[1] = {
+			.gpio =  st->pdata->gpio_os1,
+			.flags = GPIOF_DIR_OUT | ((st->oversampling & 2) ?
+				 GPIOF_INIT_HIGH : GPIOF_INIT_LOW),
+			.label = "AD7606_OS1",
+		},
+		[2] = {
+			.gpio =  st->pdata->gpio_os2,
+			.flags = GPIOF_DIR_OUT | ((st->oversampling & 4) ?
+				 GPIOF_INIT_HIGH : GPIOF_INIT_LOW),
+			.label = "AD7606_OS2",
+		},
+	};
+	int ret;
+
+	ret = gpio_request_one(st->pdata->gpio_convst, GPIOF_OUT_INIT_LOW,
+			       "AD7606_CONVST");
+	if (ret) {
+		dev_err(st->dev, "failed to request GPIO CONVST\n");
+		return ret;
+	}
+
+	ret = gpio_request_array(gpio_array, ARRAY_SIZE(gpio_array));
+	if (!ret) {
+		st->have_os = true;
+	}
+
+	ret = gpio_request_one(st->pdata->gpio_reset, GPIOF_OUT_INIT_LOW,
+			       "AD7606_RESET");
+	if (!ret)
+		st->have_reset = true;
+
+	ret = gpio_request_one(st->pdata->gpio_range, GPIOF_DIR_OUT |
+			       ((st->range == 10000) ? GPIOF_INIT_HIGH :
+			       	GPIOF_INIT_LOW), "AD7606_RANGE");
+	if (!ret)
+		st->have_range = true;
+
+	ret = gpio_request_one(st->pdata->gpio_stby, GPIOF_OUT_INIT_HIGH,
+			       "AD7606_STBY");
+	if (!ret)
+		st->have_stby = true;
+
+	if (gpio_is_valid(st->pdata->gpio_frstdata)) {
+		ret = gpio_request_one(st->pdata->gpio_frstdata, GPIOF_IN,
+				       "AD7606_FRSTDATA");
+		if (!ret)
+			st->have_frstdata = true;
+	}
+
+	return 0;
+}
+
+static void ad7606_free_gpios(struct ad7606_state *st)
+{
+	if (st->have_range)
+		gpio_free(st->pdata->gpio_range);
+
+	if (st->have_stby)
+		gpio_free(st->pdata->gpio_stby);
+
+	if (st->have_os) {
+		gpio_free(st->pdata->gpio_os0);
+		gpio_free(st->pdata->gpio_os1);
+		gpio_free(st->pdata->gpio_os2);
+	}
+
+	if (st->have_reset)
+		gpio_free(st->pdata->gpio_reset);
+
+	if (st->have_frstdata)
+		gpio_free(st->pdata->gpio_frstdata);
+
+	gpio_free(st->pdata->gpio_convst);
+}
+
+/**
+ *  Interrupt handler
+ */
+static irqreturn_t ad7606_interrupt(int irq, void *dev_id)
+{
+	struct ad7606_state *st = dev_id;
+
+	if (iio_ring_enabled(st->indio_dev)) {
+		if (!work_pending(&st->poll_work))
+			schedule_work(&st->poll_work);
+	} else {
+		st->done = true;
+		wake_up_interruptible(&st->wq_data_avail);
+	}
+
+	return IRQ_HANDLED;
+};
+
+struct ad7606_state *ad7606_probe(struct device *dev, int irq,
+			      void __iomem *base_address,
+			      unsigned id,
+			      const struct ad7606_bus_ops *bops)
+{
+	struct ad7606_platform_data *pdata = dev->platform_data;
+	struct ad7606_state *st;
+	int ret;
+
+	st = kzalloc(sizeof(*st), GFP_KERNEL);
+	if (st == NULL) {
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+
+	st->dev = dev;
+	st->id = id;
+	st->irq = irq;
+	st->bops = bops;
+	st->base_address = base_address;
+	st->range = pdata->default_range == 10000 ? 10000 : 5000;
+
+	ret = ad7606_oversampling_get_index(pdata->default_os);
+	if (ret < 0) {
+		dev_warn(dev, "oversampling %d is not supported\n",
+			 pdata->default_os);
+		st->oversampling = 0;
+	} else {
+		st->oversampling = pdata->default_os;
+	}
+
+	st->reg = regulator_get(dev, "vcc");
+	if (!IS_ERR(st->reg)) {
+		ret = regulator_enable(st->reg);
+		if (ret)
+			goto error_put_reg;
+	}
+
+	st->pdata = pdata;
+	st->chip_info = &ad7606_chip_info_tbl[id];
+
+	atomic_set(&st->protect_ring, 0);
+
+	st->indio_dev = iio_allocate_device();
+	if (st->indio_dev == NULL) {
+		ret = -ENOMEM;
+		goto error_disable_reg;
+	}
+
+	st->indio_dev->dev.parent = dev;
+	st->indio_dev->attrs = &ad7606_attribute_group;
+	st->indio_dev->dev_data = (void *)(st);
+	st->indio_dev->driver_module = THIS_MODULE;
+	st->indio_dev->modes = INDIO_DIRECT_MODE;
+
+	init_waitqueue_head(&st->wq_data_avail);
+
+	ret = ad7606_request_gpios(st);
+	if (ret)
+		goto error_free_device;
+
+	ret = ad7606_reset(st);
+	if (ret)
+		dev_warn(st->dev, "failed to RESET: no RESET GPIO specified\n");
+
+	ret = request_irq(st->irq, ad7606_interrupt,
+		IRQF_TRIGGER_FALLING, st->chip_info->name, st);
+	if (ret)
+		goto error_free_gpios;
+
+	ret = ad7606_register_ring_funcs_and_init(st->indio_dev);
+	if (ret)
+		goto error_free_irq;
+
+	ret = iio_device_register(st->indio_dev);
+	if (ret)
+		goto error_free_irq;
+
+	ret = iio_ring_buffer_register(st->indio_dev->ring, 0);
+	if (ret)
+		goto error_cleanup_ring;
+
+	return st;
+
+error_cleanup_ring:
+	ad7606_ring_cleanup(st->indio_dev);
+	iio_device_unregister(st->indio_dev);
+
+error_free_irq:
+	free_irq(st->irq, st);
+
+error_free_gpios:
+	ad7606_free_gpios(st);
+
+error_free_device:
+	iio_free_device(st->indio_dev);
+
+error_disable_reg:
+	if (!IS_ERR(st->reg))
+		regulator_disable(st->reg);
+error_put_reg:
+	if (!IS_ERR(st->reg))
+		regulator_put(st->reg);
+	kfree(st);
+error_ret:
+	return ERR_PTR(ret);
+}
+
+int ad7606_remove(struct ad7606_state *st)
+{
+	struct iio_dev *indio_dev = st->indio_dev;
+	iio_ring_buffer_unregister(indio_dev->ring);
+	ad7606_ring_cleanup(indio_dev);
+	iio_device_unregister(indio_dev);
+	free_irq(st->irq, st);
+	if (!IS_ERR(st->reg)) {
+		regulator_disable(st->reg);
+		regulator_put(st->reg);
+	}
+
+	ad7606_free_gpios(st);
+
+	kfree(st);
+	return 0;
+}
+
+void ad7606_suspend(struct ad7606_state *st)
+{
+	if (st->have_stby) {
+		if (st->have_range)
+			gpio_set_value(st->pdata->gpio_range, 1);
+		gpio_set_value(st->pdata->gpio_stby, 0);
+	}
+}
+
+void ad7606_resume(struct ad7606_state *st)
+{
+	if (st->have_stby) {
+		if (st->have_range)
+			gpio_set_value(st->pdata->gpio_range,
+					st->range == 10000);
+
+		gpio_set_value(st->pdata->gpio_stby, 1);
+		ad7606_reset(st);
+	}
+}
+
+MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
+MODULE_DESCRIPTION("Analog Devices AD7606 ADC");
+MODULE_LICENSE("GPL v2");