staging: iio: adc: new driver for AD7816 devices

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/adc/Kconfig

@@ -106,3 +106,10 @@ config AD7745
 
 	  To compile this driver as a module, choose M here: the
 	  module will be called ad7745.
+
+config AD7816
+	tristate "Analog Devices AD7816/7/8 temperature sensor and ADC driver"
+	depends on SPI
+	help
+	  Say yes here to build support for Analog Devices AD7816/7/8
+	  temperature sensors and ADC.

drivers/staging/iio/adc/Makefile

@@ -21,3 +21,4 @@ obj-$(CONFIG_AD7291) += ad7291.o
 obj-$(CONFIG_AD7298) += ad7298.o
 obj-$(CONFIG_AD7314) += ad7314.o
 obj-$(CONFIG_AD7745) += ad7745.o
+obj-$(CONFIG_AD7816) += ad7816.o

drivers/staging/iio/adc/ad7816.c

+/*
+ * AD7816 digital temperature sensor driver supporting AD7816/7/8
+ *
+ * Copyright 2010 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/gpio.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/spi/spi.h>
+#include <linux/rtc.h>
+
+#include "../iio.h"
+#include "../sysfs.h"
+
+/*
+ * AD7816 config masks
+ */
+#define AD7816_FULL			0x1
+#define AD7816_PD			0x2
+#define AD7816_CS_MASK			0x7
+#define AD7816_CS_MAX			0x4
+
+/*
+ * AD7816 temperature masks
+ */
+#define AD7816_VALUE_OFFSET		6
+#define AD7816_BOUND_VALUE_BASE		0x8
+#define AD7816_BOUND_VALUE_MIN		-95
+#define AD7816_BOUND_VALUE_MAX		152
+#define AD7816_TEMP_FLOAT_OFFSET	2
+#define AD7816_TEMP_FLOAT_MASK		0x3
+
+
+/*
+ * struct ad7816_chip_info - chip specifc information
+ */
+
+struct ad7816_chip_info {
+	const char *name;
+	struct spi_device *spi_dev;
+	struct iio_dev *indio_dev;
+	struct work_struct thresh_work;
+	s64 last_timestamp;
+	u16 rdwr_pin;
+	u16 convert_pin;
+	u16 busy_pin;
+	u8  oti_data[AD7816_CS_MAX+1];
+	u8  channel_id;	/* 0 always be temperature */
+	u8  mode;
+};
+
+/*
+ * ad7816 data access by SPI
+ */
+static int ad7816_spi_read(struct ad7816_chip_info *chip, u16 *data)
+{
+	struct spi_device *spi_dev = chip->spi_dev;
+	int ret = 0;
+
+	gpio_set_value(chip->rdwr_pin, 1);
+	gpio_set_value(chip->rdwr_pin, 0);
+	ret = spi_write(spi_dev, &chip->channel_id, sizeof(chip->channel_id));
+	if (ret < 0) {
+		dev_err(&spi_dev->dev, "SPI channel setting error\n");
+		return ret;
+	}
+	gpio_set_value(chip->rdwr_pin, 1);
+
+
+	if (chip->mode == AD7816_PD) { /* operating mode 2 */
+		gpio_set_value(chip->convert_pin, 1);
+		gpio_set_value(chip->convert_pin, 0);
+	} else { /* operating mode 1 */
+		gpio_set_value(chip->convert_pin, 0);
+		gpio_set_value(chip->convert_pin, 1);
+	}
+
+	while (gpio_get_value(chip->busy_pin))
+		cpu_relax();
+
+	gpio_set_value(chip->rdwr_pin, 0);
+	gpio_set_value(chip->rdwr_pin, 1);
+	ret = spi_read(spi_dev, (u8 *)data, sizeof(*data));
+	if (ret < 0) {
+		dev_err(&spi_dev->dev, "SPI data read error\n");
+		return ret;
+	}
+
+	*data = be16_to_cpu(*data);
+
+	return ret;
+}
+
+static int ad7816_spi_write(struct ad7816_chip_info *chip, u8 data)
+{
+	struct spi_device *spi_dev = chip->spi_dev;
+	int ret = 0;
+
+	gpio_set_value(chip->rdwr_pin, 1);
+	gpio_set_value(chip->rdwr_pin, 0);
+	ret = spi_write(spi_dev, &data, sizeof(data));
+	if (ret < 0)
+		dev_err(&spi_dev->dev, "SPI oti data write error\n");
+
+	return ret;
+}
+
+static ssize_t ad7816_show_mode(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7816_chip_info *chip = dev_info->dev_data;
+
+	if (chip->mode)
+		return sprintf(buf, "power-save\n");
+	else
+		return sprintf(buf, "full\n");
+}
+
+static ssize_t ad7816_store_mode(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf,
+		size_t len)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7816_chip_info *chip = dev_info->dev_data;
+
+	if (strcmp(buf, "full")) {
+		gpio_set_value(chip->rdwr_pin, 1);
+		chip->mode = AD7816_FULL;
+	} else {
+		gpio_set_value(chip->rdwr_pin, 0);
+		chip->mode = AD7816_PD;
+	}
+
+	return len;
+}
+
+static IIO_DEVICE_ATTR(mode, S_IRUGO | S_IWUSR,
+		ad7816_show_mode,
+		ad7816_store_mode,
+		0);
+
+static ssize_t ad7816_show_available_modes(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	return sprintf(buf, "full\npower-save\n");
+}
+
+static IIO_DEVICE_ATTR(available_modes, S_IRUGO, ad7816_show_available_modes, NULL, 0);
+
+static ssize_t ad7816_show_channel(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7816_chip_info *chip = dev_info->dev_data;
+
+	return sprintf(buf, "%d\n", chip->channel_id);
+}
+
+static ssize_t ad7816_store_channel(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf,
+		size_t len)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7816_chip_info *chip = dev_info->dev_data;
+	unsigned long data;
+	int ret;
+
+	ret = strict_strtoul(buf, 10, &data);
+	if (ret)
+		return -EINVAL;
+
+	if (data > AD7816_CS_MAX && data != AD7816_CS_MASK) {
+		dev_err(&chip->spi_dev->dev, "Invalid channel id %lu for %s.\n",
+			data, chip->name);
+		return -EINVAL;
+	} else if (strcmp(chip->name, "ad7818") == 0 && data > 1) {
+		dev_err(&chip->spi_dev->dev,
+			"Invalid channel id %lu for ad7818.\n", data);
+		return -EINVAL;
+	} else if (strcmp(chip->name, "ad7816") == 0 && data > 0) {
+		dev_err(&chip->spi_dev->dev,
+			"Invalid channel id %lu for ad7816.\n", data);
+		return -EINVAL;
+	}
+
+	chip->channel_id = data;
+
+	return len;
+}
+
+static IIO_DEVICE_ATTR(channel, S_IRUGO | S_IWUSR,
+		ad7816_show_channel,
+		ad7816_store_channel,
+		0);
+
+
+static ssize_t ad7816_show_value(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7816_chip_info *chip = dev_info->dev_data;
+	u16 data;
+	s8 value;
+	int ret;
+
+	ret = ad7816_spi_read(chip, &data);
+	if (ret)
+		return -EIO;
+
+	data >>= AD7816_VALUE_OFFSET;
+
+	if (chip->channel_id == 0) {
+		value = (s8)((data >> AD7816_TEMP_FLOAT_OFFSET) - 103);
+		data &= AD7816_TEMP_FLOAT_MASK;
+		if (value < 0)
+			data = (1 << AD7816_TEMP_FLOAT_OFFSET) - data;
+		return sprintf(buf, "%d.%.2d\n", value, data * 25);
+	} else
+		return sprintf(buf, "%u\n", data);
+}
+
+static IIO_DEVICE_ATTR(value, S_IRUGO, ad7816_show_value, NULL, 0);
+
+static ssize_t ad7816_show_name(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7816_chip_info *chip = dev_info->dev_data;
+	return sprintf(buf, "%s\n", chip->name);
+}
+
+static IIO_DEVICE_ATTR(name, S_IRUGO, ad7816_show_name, NULL, 0);
+
+static struct attribute *ad7816_attributes[] = {
+	&iio_dev_attr_available_modes.dev_attr.attr,
+	&iio_dev_attr_mode.dev_attr.attr,
+	&iio_dev_attr_channel.dev_attr.attr,
+	&iio_dev_attr_value.dev_attr.attr,
+	&iio_dev_attr_name.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ad7816_attribute_group = {
+	.attrs = ad7816_attributes,
+};
+
+/*
+ * temperature bound events
+ */
+
+#define IIO_EVENT_CODE_AD7816_OTI    IIO_BUFFER_EVENT_CODE(0)
+
+static void ad7816_interrupt_bh(struct work_struct *work_s)
+{
+	struct ad7816_chip_info *chip =
+		container_of(work_s, struct ad7816_chip_info, thresh_work);
+
+	enable_irq(chip->spi_dev->irq);
+
+	iio_push_event(chip->indio_dev, 0,
+			IIO_EVENT_CODE_AD7816_OTI,
+			chip->last_timestamp);
+}
+
+static int ad7816_interrupt(struct iio_dev *dev_info,
+		int index,
+		s64 timestamp,
+		int no_test)
+{
+	struct ad7816_chip_info *chip = dev_info->dev_data;
+
+	chip->last_timestamp = timestamp;
+	schedule_work(&chip->thresh_work);
+
+	return 0;
+}
+
+IIO_EVENT_SH(ad7816, &ad7816_interrupt);
+
+static ssize_t ad7816_show_oti(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7816_chip_info *chip = dev_info->dev_data;
+	int value;
+
+	if (chip->channel_id > AD7816_CS_MAX) {
+		dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
+		return -EINVAL;
+	} else if (chip->channel_id == 0) {
+		value = AD7816_BOUND_VALUE_MIN +
+			(chip->oti_data[chip->channel_id] -
+			AD7816_BOUND_VALUE_BASE);
+		return sprintf(buf, "%d\n", value);
+	} else
+		return sprintf(buf, "%u\n", chip->oti_data[chip->channel_id]);
+}
+
+static inline ssize_t ad7816_set_oti(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf,
+		size_t len)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7816_chip_info *chip = dev_info->dev_data;
+	long value;
+	u8 data;
+	int ret;
+
+	ret = strict_strtol(buf, 10, &value);
+
+	if (chip->channel_id > AD7816_CS_MAX) {
+		dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
+		return -EINVAL;
+	} else if (chip->channel_id == 0) {
+		if (ret || value < AD7816_BOUND_VALUE_MIN ||
+			value > AD7816_BOUND_VALUE_MAX)
+			return -EINVAL;
+
+		data = (u8)(value - AD7816_BOUND_VALUE_MIN +
+			AD7816_BOUND_VALUE_BASE);
+	} else {
+		if (ret || value < AD7816_BOUND_VALUE_BASE || value > 255)
+			return -EINVAL;
+
+		data = (u8)value;
+	}
+
+	ret = ad7816_spi_write(chip, data);
+	if (ret)
+		return -EIO;
+
+	chip->oti_data[chip->channel_id] = data;
+
+	return len;
+}
+
+IIO_EVENT_ATTR_SH(oti, iio_event_ad7816,
+		ad7816_show_oti, ad7816_set_oti, 0);
+
+static struct attribute *ad7816_event_attributes[] = {
+	&iio_event_attr_oti.dev_attr.attr,
+	NULL,
+};
+
+static struct attribute_group ad7816_event_attribute_group = {
+	.attrs = ad7816_event_attributes,
+};
+
+/*
+ * device probe and remove
+ */
+
+static int __devinit ad7816_probe(struct spi_device *spi_dev)
+{
+	struct ad7816_chip_info *chip;
+	unsigned short *pins = spi_dev->dev.platform_data;
+	int ret = 0;
+	int i;
+
+	if (!pins) {
+		dev_err(&spi_dev->dev, "No necessary GPIO platform data.\n");
+		return -EINVAL;
+	}
+
+	chip = kzalloc(sizeof(struct ad7816_chip_info), GFP_KERNEL);
+
+	if (chip == NULL)
+		return -ENOMEM;
+
+	/* this is only used for device removal purposes */
+	dev_set_drvdata(&spi_dev->dev, chip);
+
+	chip->spi_dev = spi_dev;
+	chip->name = spi_dev->modalias;
+	for (i = 0; i <= AD7816_CS_MAX; i++)
+		chip->oti_data[i] = 203;
+	chip->rdwr_pin = pins[0];
+	chip->convert_pin = pins[1];
+	chip->busy_pin = pins[2];
+
+	ret = gpio_request(chip->rdwr_pin, chip->name);
+	if (ret) {
+		dev_err(&spi_dev->dev, "Fail to request rdwr gpio PIN %d.\n",
+			chip->rdwr_pin);
+		goto error_free_chip;
+	}
+	gpio_direction_input(chip->rdwr_pin);
+	ret = gpio_request(chip->convert_pin, chip->name);
+	if (ret) {
+		dev_err(&spi_dev->dev, "Fail to request convert gpio PIN %d.\n",
+			chip->convert_pin);
+		goto error_free_gpio_rdwr;
+	}
+	gpio_direction_input(chip->convert_pin);
+	ret = gpio_request(chip->busy_pin, chip->name);
+	if (ret) {
+		dev_err(&spi_dev->dev, "Fail to request busy gpio PIN %d.\n",
+			chip->busy_pin);
+		goto error_free_gpio_convert;
+	}
+	gpio_direction_input(chip->busy_pin);
+
+	chip->indio_dev = iio_allocate_device();
+	if (chip->indio_dev == NULL) {
+		ret = -ENOMEM;
+		goto error_free_gpio;
+	}
+
+	chip->indio_dev->dev.parent = &spi_dev->dev;
+	chip->indio_dev->attrs = &ad7816_attribute_group;
+	chip->indio_dev->event_attrs = &ad7816_event_attribute_group;
+	chip->indio_dev->dev_data = (void *)chip;
+	chip->indio_dev->driver_module = THIS_MODULE;
+	chip->indio_dev->num_interrupt_lines = 1;
+	chip->indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = iio_device_register(chip->indio_dev);
+	if (ret)
+		goto error_free_dev;
+
+	if (spi_dev->irq) {
+		/* Only low trigger is supported in ad7816/7/8 */
+		ret = iio_register_interrupt_line(spi_dev->irq,
+				chip->indio_dev,
+				0,
+				IRQF_TRIGGER_LOW,
+				chip->name);
+		if (ret)
+			goto error_unreg_dev;
+
+		/*
+		 * The event handler list element refer to iio_event_ad7816.
+		 * All event attributes bind to the same event handler.
+		 * So, only register event handler once.
+		 */
+		iio_add_event_to_list(&iio_event_ad7816,
+				&chip->indio_dev->interrupts[0]->ev_list);
+
+		INIT_WORK(&chip->thresh_work, ad7816_interrupt_bh);
+	}
+
+	dev_info(&spi_dev->dev, "%s temperature sensor and ADC registered.\n",
+			 chip->name);
+
+	return 0;
+
+error_unreg_dev:
+	iio_device_unregister(chip->indio_dev);
+error_free_dev:
+	iio_free_device(chip->indio_dev);
+error_free_gpio:
+	gpio_free(chip->busy_pin);
+error_free_gpio_convert:
+	gpio_free(chip->convert_pin);
+error_free_gpio_rdwr:
+	gpio_free(chip->rdwr_pin);
+error_free_chip:
+	kfree(chip);
+
+	return ret;
+}
+
+static int __devexit ad7816_remove(struct spi_device *spi_dev)
+{
+	struct ad7816_chip_info *chip = dev_get_drvdata(&spi_dev->dev);
+	struct iio_dev *indio_dev = chip->indio_dev;
+
+	dev_set_drvdata(&spi_dev->dev, NULL);
+	if (spi_dev->irq)
+		iio_unregister_interrupt_line(indio_dev, 0);
+	iio_device_unregister(indio_dev);
+	iio_free_device(chip->indio_dev);
+	gpio_free(chip->busy_pin);
+	gpio_free(chip->convert_pin);
+	gpio_free(chip->rdwr_pin);
+	kfree(chip);
+
+	return 0;
+}
+
+static const struct spi_device_id ad7816_id[] = {
+	{ "ad7816", 0 },
+	{ "ad7817", 0 },
+	{ "ad7818", 0 },
+	{}
+};
+
+MODULE_DEVICE_TABLE(spi, ad7816_id);
+
+static struct spi_driver ad7816_driver = {
+	.driver = {
+		.name = "ad7816",
+		.bus = &spi_bus_type,
+		.owner = THIS_MODULE,
+	},
+	.probe = ad7816_probe,
+	.remove = __devexit_p(ad7816_remove),
+	.id_table = ad7816_id,
+};
+
+static __init int ad7816_init(void)
+{
+	return spi_register_driver(&ad7816_driver);
+}
+
+static __exit void ad7816_exit(void)
+{
+	spi_unregister_driver(&ad7816_driver);
+}
+
+MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD7816/7/8 digital"
+			" temperature sensor driver");
+MODULE_LICENSE("GPL v2");
+
+module_init(ad7816_init);
+module_exit(ad7816_exit);