staging: iio: adc: new driver for AD7298 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

@@ -48,6 +48,13 @@ config AD7291
 	  Say yes here to build support for Analog Devices AD7291
 	  temperature sensors.
 
+config AD7298
+	tristate "Analog Devices AD7298 temperature sensor and ADC driver"
+	depends on SPI
+	help
+	  Say yes here to build support for Analog Devices AD7298
+	  temperature sensors and ADC.
+
 config AD799X
 	tristate "Analog Devices AD799x ADC driver"
 	depends on I2C

drivers/staging/iio/adc/Makefile

@@ -18,3 +18,4 @@ obj-$(CONFIG_AD7476) += ad7476.o
 obj-$(CONFIG_AD7150) += ad7150.o
 obj-$(CONFIG_AD7152) += ad7152.o
 obj-$(CONFIG_AD7291) += ad7291.o
+obj-$(CONFIG_AD7298) += ad7298.o

drivers/staging/iio/adc/ad7298.c

+/*
+ * AD7298 digital temperature sensor driver supporting AD7298
+ *
+ * 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"
+
+/*
+ * AD7298 command
+ */
+#define AD7298_PD			0x1
+#define AD7298_T_AVG_MASK		0x2
+#define AD7298_EXT_REF			0x4
+#define AD7298_T_SENSE_MASK		0x20
+#define AD7298_VOLTAGE_MASK		0x3fc0
+#define AD7298_VOLTAGE_OFFSET		0x6
+#define AD7298_VOLTAGE_LIMIT_COUNT	8
+#define AD7298_REPEAT			0x40
+#define AD7298_WRITE			0x80
+
+/*
+ * AD7298 value masks
+ */
+#define AD7298_CHANNEL_MASK		0xf000
+#define AD7298_VALUE_MASK		0xfff
+#define AD7298_T_VALUE_SIGN		0x400
+#define AD7298_T_VALUE_FLOAT_OFFSET	2
+#define AD7298_T_VALUE_FLOAT_MASK	0x2
+
+/*
+ * struct ad7298_chip_info - chip specifc information
+ */
+
+struct ad7298_chip_info {
+	const char *name;
+	struct spi_device *spi_dev;
+	struct iio_dev *indio_dev;
+	u16 command;
+	u16 busy_pin;
+	u8  channels;	/* Active voltage channels */
+};
+
+/*
+ * ad7298 register access by SPI
+ */
+static int ad7298_spi_write(struct ad7298_chip_info *chip, u16 data)
+{
+	struct spi_device *spi_dev = chip->spi_dev;
+	int ret = 0;
+
+	data |= AD7298_WRITE;
+	data = cpu_to_be16(data);
+	ret = spi_write(spi_dev, (u8 *)&data, sizeof(data));
+	if (ret < 0)
+		dev_err(&spi_dev->dev, "SPI write error\n");
+
+	return ret;
+}
+
+static int ad7298_spi_read(struct ad7298_chip_info *chip, u16 mask, u16 *data)
+{
+	struct spi_device *spi_dev = chip->spi_dev;
+	int ret = 0;
+	u8 count = chip->channels;
+	u16 command;
+	int i;
+
+	if (mask & AD7298_T_SENSE_MASK) {
+		command = chip->command & ~(AD7298_T_AVG_MASK | AD7298_VOLTAGE_MASK);
+		command |= AD7298_T_SENSE_MASK;
+		count = 1;
+	} else if (mask & AD7298_T_AVG_MASK) {
+		command = chip->command & ~AD7298_VOLTAGE_MASK;
+		command |= AD7298_T_SENSE_MASK | AD7298_T_AVG_MASK;
+		count = 2;
+	} else if (mask & AD7298_VOLTAGE_MASK) {
+		command = chip->command & ~(AD7298_T_AVG_MASK | AD7298_T_SENSE_MASK);
+		count = chip->channels;
+	}
+
+	ret = ad7298_spi_write(chip, chip->command);
+	if (ret < 0) {
+		dev_err(&spi_dev->dev, "SPI write command error\n");
+		return ret;
+	}
+
+	ret = spi_read(spi_dev, (u8 *)&command, sizeof(command));
+	if (ret < 0) {
+		dev_err(&spi_dev->dev, "SPI read error\n");
+		return ret;
+	}
+
+	i = 10000;
+	while (i && gpio_get_value(chip->busy_pin)) {
+		cpu_relax();
+		i--;
+	}
+	if (!i) {
+		dev_err(&spi_dev->dev, "Always in busy convertion.\n");
+		return -EBUSY;
+	}
+
+	for (i = 0; i < count; i++) {
+		ret = spi_read(spi_dev, (u8 *)&data[i], sizeof(data[i]));
+		if (ret < 0) {
+			dev_err(&spi_dev->dev, "SPI read error\n");
+			return ret;
+		}
+		*data = be16_to_cpu(data[i]);
+	}
+
+	return 0;
+}
+
+static ssize_t ad7298_show_mode(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7298_chip_info *chip = dev_info->dev_data;
+
+	if (chip->command & AD7298_REPEAT)
+		return sprintf(buf, "repeat\n");
+	else
+		return sprintf(buf, "normal\n");
+}
+
+static ssize_t ad7298_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 ad7298_chip_info *chip = dev_info->dev_data;
+
+	if (strcmp(buf, "repeat"))
+		chip->command |= AD7298_REPEAT;
+	else
+		chip->command &= (~AD7298_REPEAT);
+
+	return 1;
+}
+
+static IIO_DEVICE_ATTR(mode, S_IRUGO | S_IWUSR,
+		ad7298_show_mode,
+		ad7298_store_mode,
+		0);
+
+static ssize_t ad7298_show_available_modes(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	return sprintf(buf, "normal\nrepeat\n");
+}
+
+static IIO_DEVICE_ATTR(available_modes, S_IRUGO, ad7298_show_available_modes, NULL, 0);
+
+static ssize_t ad7298_store_reset(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf,
+		size_t len)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7298_chip_info *chip = dev_info->dev_data;
+	u16 command;
+	int ret;
+
+	command = chip->command & ~AD7298_PD;
+
+	ret = ad7298_spi_write(chip, command);
+	if (ret)
+		return -EIO;
+
+	command = chip->command | AD7298_PD;
+
+	ret = ad7298_spi_write(chip, command);
+	if (ret)
+		return -EIO;
+
+	return len;
+}
+
+static IIO_DEVICE_ATTR(reset, S_IWUSR,
+		NULL,
+		ad7298_store_reset,
+		0);
+
+static ssize_t ad7298_show_ext_ref(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7298_chip_info *chip = dev_info->dev_data;
+
+	return sprintf(buf, "%d\n", !!(chip->command & AD7298_EXT_REF));
+}
+
+static ssize_t ad7298_store_ext_ref(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf,
+		size_t len)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7298_chip_info *chip = dev_info->dev_data;
+	u16 command;
+	int ret;
+
+	command = chip->command & (~AD7298_EXT_REF);
+	if (strcmp(buf, "1"))
+		command |= AD7298_EXT_REF;
+
+	ret = ad7298_spi_write(chip, command);
+	if (ret)
+		return -EIO;
+
+	chip->command = command;
+
+	return len;
+}
+
+static IIO_DEVICE_ATTR(ext_ref, S_IRUGO | S_IWUSR,
+		ad7298_show_ext_ref,
+		ad7298_store_ext_ref,
+		0);
+
+static ssize_t ad7298_show_t_sense(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7298_chip_info *chip = dev_info->dev_data;
+	u16 data;
+	char sign = ' ';
+	int ret;
+
+	ret = ad7298_spi_read(chip, AD7298_T_SENSE_MASK, &data);
+	if (ret)
+		return -EIO;
+
+	if (data & AD7298_T_VALUE_SIGN) {
+		/* convert supplement to positive value */
+		data = (AD7298_T_VALUE_SIGN << 1) - data;
+		sign = '-';
+	}
+
+	return sprintf(buf, "%c%d.%.2d\n", sign,
+		(data >> AD7298_T_VALUE_FLOAT_OFFSET),
+		(data & AD7298_T_VALUE_FLOAT_MASK) * 25);
+}
+
+static IIO_DEVICE_ATTR(t_sense, S_IRUGO, ad7298_show_t_sense, NULL, 0);
+
+static ssize_t ad7298_show_t_average(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7298_chip_info *chip = dev_info->dev_data;
+	u16 data[2];
+	char sign = ' ';
+	int ret;
+
+	ret = ad7298_spi_read(chip, AD7298_T_AVG_MASK, data);
+	if (ret)
+		return -EIO;
+
+	if (data[1] & AD7298_T_VALUE_SIGN) {
+		/* convert supplement to positive value */
+		data[1] = (AD7298_T_VALUE_SIGN << 1) - data[1];
+		sign = '-';
+	}
+
+	return sprintf(buf, "%c%d.%.2d\n", sign,
+		(data[1] >> AD7298_T_VALUE_FLOAT_OFFSET),
+		(data[1] & AD7298_T_VALUE_FLOAT_MASK) * 25);
+}
+
+static IIO_DEVICE_ATTR(t_average, S_IRUGO, ad7298_show_t_average, NULL, 0);
+
+static ssize_t ad7298_show_voltage(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7298_chip_info *chip = dev_info->dev_data;
+	u16 data[AD7298_VOLTAGE_LIMIT_COUNT];
+	int i, size, ret;
+
+	ret = ad7298_spi_read(chip, AD7298_VOLTAGE_MASK, data);
+	if (ret)
+		return -EIO;
+
+	for (i = 0; i < AD7298_VOLTAGE_LIMIT_COUNT; i++) {
+		if (chip->command & (AD7298_T_SENSE_MASK << i)) {
+			ret = sprintf(buf, "channel[%d]=%d\n", i,
+					data[i] & AD7298_VALUE_MASK);
+			if (ret < 0)
+				break;
+			buf += ret;
+			size += ret;
+		}
+	}
+
+	return size;
+}
+
+static IIO_DEVICE_ATTR(voltage, S_IRUGO, ad7298_show_voltage, NULL, 0);
+
+static ssize_t ad7298_show_channel_mask(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7298_chip_info *chip = dev_info->dev_data;
+
+	return sprintf(buf, "0x%x\n", (chip->command & AD7298_VOLTAGE_MASK) >>
+			AD7298_VOLTAGE_OFFSET);
+}
+
+static ssize_t ad7298_store_channel_mask(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf,
+		size_t len)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7298_chip_info *chip = dev_info->dev_data;
+	unsigned long data;
+	int i, ret;
+
+	ret = strict_strtoul(buf, 16, &data);
+	if (ret || data > 0xff)
+		return -EINVAL;
+
+	chip->command &= (~AD7298_VOLTAGE_MASK);
+	chip->command |= data << AD7298_VOLTAGE_OFFSET;
+
+	for (i = 0, chip->channels = 0; i < AD7298_VOLTAGE_LIMIT_COUNT; i++) {
+		if (chip->command & (AD7298_T_SENSE_MASK << i))
+			chip->channels++;
+	}
+
+	return ret;
+}
+
+static IIO_DEVICE_ATTR(channel_mask, S_IRUGO | S_IWUSR,
+		ad7298_show_channel_mask,
+		ad7298_store_channel_mask,
+		0);
+
+static ssize_t ad7298_show_name(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	struct iio_dev *dev_info = dev_get_drvdata(dev);
+	struct ad7298_chip_info *chip = dev_info->dev_data;
+	return sprintf(buf, "%s\n", chip->name);
+}
+
+static IIO_DEVICE_ATTR(name, S_IRUGO, ad7298_show_name, NULL, 0);
+
+static struct attribute *ad7298_attributes[] = {
+	&iio_dev_attr_available_modes.dev_attr.attr,
+	&iio_dev_attr_mode.dev_attr.attr,
+	&iio_dev_attr_reset.dev_attr.attr,
+	&iio_dev_attr_ext_ref.dev_attr.attr,
+	&iio_dev_attr_t_sense.dev_attr.attr,
+	&iio_dev_attr_t_average.dev_attr.attr,
+	&iio_dev_attr_voltage.dev_attr.attr,
+	&iio_dev_attr_channel_mask.dev_attr.attr,
+	&iio_dev_attr_name.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ad7298_attribute_group = {
+	.attrs = ad7298_attributes,
+};
+
+/*
+ * device probe and remove
+ */
+static int __devinit ad7298_probe(struct spi_device *spi_dev)
+{
+	struct ad7298_chip_info *chip;
+	unsigned short *pins = spi_dev->dev.platform_data;
+	int ret = 0;
+
+	chip = kzalloc(sizeof(struct ad7298_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;
+	chip->busy_pin = pins[0];
+
+	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_chip;
+	}
+	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 = &ad7298_attribute_group;
+	chip->indio_dev->dev_data = (void *)chip;
+	chip->indio_dev->driver_module = THIS_MODULE;
+	chip->indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = iio_device_register(chip->indio_dev);
+	if (ret)
+		goto error_free_dev;
+
+	dev_info(&spi_dev->dev, "%s temperature sensor and ADC registered.\n",
+			 chip->name);
+
+	return 0;
+
+error_free_dev:
+	iio_free_device(chip->indio_dev);
+error_free_gpio:
+	gpio_free(chip->busy_pin);
+error_free_chip:
+	kfree(chip);
+
+	return ret;
+}
+
+static int __devexit ad7298_remove(struct spi_device *spi_dev)
+{
+	struct ad7298_chip_info *chip = dev_get_drvdata(&spi_dev->dev);
+	struct iio_dev *indio_dev = chip->indio_dev;
+
+	dev_set_drvdata(&spi_dev->dev, NULL);
+	iio_device_unregister(indio_dev);
+	iio_free_device(chip->indio_dev);
+	gpio_free(chip->busy_pin);
+	kfree(chip);
+
+	return 0;
+}
+
+static const struct spi_device_id ad7298_id[] = {
+	{ "ad7298", 0 },
+	{}
+};
+
+MODULE_DEVICE_TABLE(spi, ad7298_id);
+
+static struct spi_driver ad7298_driver = {
+	.driver = {
+		.name = "ad7298",
+		.bus = &spi_bus_type,
+		.owner = THIS_MODULE,
+	},
+	.probe = ad7298_probe,
+	.remove = __devexit_p(ad7298_remove),
+	.id_table = ad7298_id,
+};
+
+static __init int ad7298_init(void)
+{
+	return spi_register_driver(&ad7298_driver);
+}
+
+static __exit void ad7298_exit(void)
+{
+	spi_unregister_driver(&ad7298_driver);
+}
+
+MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD7298 digital"
+			" temperature sensor and ADC driver");
+MODULE_LICENSE("GPL v2");
+
+module_init(ad7298_init);
+module_exit(ad7298_exit);