diff options
Diffstat (limited to 'drivers/hwmon/ad7314.c')
| -rw-r--r-- | drivers/hwmon/ad7314.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/drivers/hwmon/ad7314.c b/drivers/hwmon/ad7314.c new file mode 100644 index 00000000000..318e38e8537 --- /dev/null +++ b/drivers/hwmon/ad7314.c @@ -0,0 +1,186 @@ +/* + * AD7314 digital temperature sensor driver for AD7314, ADT7301 and ADT7302 + * + * Copyright 2010 Analog Devices Inc. + * + * Licensed under the GPL-2 or later. + * + * Conversion to hwmon from IIO done by Jonathan Cameron <jic23@cam.ac.uk> + */ +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/sysfs.h> +#include <linux/spi/spi.h> +#include <linux/module.h> +#include <linux/err.h> +#include <linux/hwmon.h> +#include <linux/hwmon-sysfs.h> + +/* + * AD7314 power mode + */ +#define AD7314_PD 0x2000 + +/* + * AD7314 temperature masks + */ +#define AD7314_TEMP_SIGN 0x200 +#define AD7314_TEMP_MASK 0x7FE0 +#define AD7314_TEMP_OFFSET 5 + +/* + * ADT7301 and ADT7302 temperature masks + */ +#define ADT7301_TEMP_SIGN 0x2000 +#define ADT7301_TEMP_MASK 0x3FFF + +enum ad7314_variant { + adt7301, + adt7302, + ad7314, +}; + +struct ad7314_data { + struct spi_device *spi_dev; + struct device *hwmon_dev; + u16 rx ____cacheline_aligned; +}; + +static int ad7314_spi_read(struct ad7314_data *chip, s16 *data) +{ + int ret; + + ret = spi_read(chip->spi_dev, (u8 *)&chip->rx, sizeof(chip->rx)); + if (ret < 0) { + dev_err(&chip->spi_dev->dev, "SPI read error\n"); + return ret; + } + + *data = be16_to_cpu(chip->rx); + + return ret; +} + +static ssize_t ad7314_show_temperature(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct ad7314_data *chip = dev_get_drvdata(dev); + s16 data; + int ret; + + ret = ad7314_spi_read(chip, &data); + if (ret < 0) + return ret; + switch (spi_get_device_id(chip->spi_dev)->driver_data) { + case ad7314: + data = (data & AD7314_TEMP_MASK) >> AD7314_TEMP_OFFSET; + data = (data << 6) >> 6; + + return sprintf(buf, "%d\n", 250 * data); + case adt7301: + case adt7302: + /* + * Documented as a 13 bit twos complement register + * with a sign bit - which is a 14 bit 2's complement + * register. 1lsb - 31.25 milli degrees centigrade + */ + data &= ADT7301_TEMP_MASK; + data = (data << 2) >> 2; + + return sprintf(buf, "%d\n", + DIV_ROUND_CLOSEST(data * 3125, 100)); + default: + return -EINVAL; + } +} + +static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, + ad7314_show_temperature, NULL, 0); + +static struct attribute *ad7314_attributes[] = { + &sensor_dev_attr_temp1_input.dev_attr.attr, + NULL, +}; + +static const struct attribute_group ad7314_group = { + .attrs = ad7314_attributes, +}; + +static int __devinit ad7314_probe(struct spi_device *spi_dev) +{ + int ret; + struct ad7314_data *chip; + + chip = kzalloc(sizeof(*chip), GFP_KERNEL); + if (chip == NULL) { + ret = -ENOMEM; + goto error_ret; + } + dev_set_drvdata(&spi_dev->dev, chip); + + ret = sysfs_create_group(&spi_dev->dev.kobj, &ad7314_group); + if (ret < 0) + goto error_free_chip; + chip->hwmon_dev = hwmon_device_register(&spi_dev->dev); + if (IS_ERR(chip->hwmon_dev)) { + ret = PTR_ERR(chip->hwmon_dev); + goto error_remove_group; + } + + return 0; +error_remove_group: + sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group); +error_free_chip: + kfree(chip); +error_ret: + return ret; +} + +static int __devexit ad7314_remove(struct spi_device *spi_dev) +{ + struct ad7314_data *chip = dev_get_drvdata(&spi_dev->dev); + + hwmon_device_unregister(chip->hwmon_dev); + sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group); + kfree(chip); + + return 0; +} + +static const struct spi_device_id ad7314_id[] = { + { "adt7301", adt7301 }, + { "adt7302", adt7302 }, + { "ad7314", ad7314 }, + { } +}; +MODULE_DEVICE_TABLE(spi, ad7314_id); + +static struct spi_driver ad7314_driver = { + .driver = { + .name = "ad7314", + .bus = &spi_bus_type, + .owner = THIS_MODULE, + }, + .probe = ad7314_probe, + .remove = __devexit_p(ad7314_remove), + .id_table = ad7314_id, +}; + +static __init int ad7314_init(void) +{ + return spi_register_driver(&ad7314_driver); +} +module_init(ad7314_init); + +static __exit void ad7314_exit(void) +{ + spi_unregister_driver(&ad7314_driver); +} +module_exit(ad7314_exit); + +MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>"); +MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital" + " temperature sensor driver"); +MODULE_LICENSE("GPL v2"); |