hwmon: AD7314 driver (ported from IIO)

Driver for AD7314, ADT7301, and ADT7302, ported from IIO.

Currently dropped power down mode support.

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
[guenter.roeck@ericsson.com: Added MODULE_DEVICE_TABLE]
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>

diff --git a/Documentation/hwmon/ad7314 b/Documentation/hwmon/ad7314
new file mode 100644 (file)
index 0000000..1912549
--- /dev/null
+++ b/Documentation/hwmon/ad7314
@@ -0,0 +1,25 @@
+Kernel driver ad7314
+====================
+
+Supported chips:
+   * Analog Devices AD7314
+     Prefix: 'ad7314'
+     Datasheet: Publicly available at Analog Devices website.
+   * Analog Devices ADT7301
+     Prefix: 'adt7301'
+     Datasheet: Publicly available at Analog Devices website.
+   * Analog Devices ADT7302
+     Prefix: 'adt7302'
+     Datasheet: Publicly available at Analog Devices website.
+
+Description
+-----------
+
+Driver supports the above parts.  The ad7314 has a 10 bit
+sensor with 1lsb = 0.25 degrees centigrade. The adt7301 and
+adt7302 have 14 bit sensors with 1lsb = 0.03125 degrees centigrade.
+
+Notes
+-----
+
+Currently power down mode is not supported.

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index c6fb761..378ed8a 100644 (file)
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -68,6 +68,16 @@ config SENSORS_ABITUGURU3
          This driver can also be built as a module.  If so, the module
          will be called abituguru3.
 
+config SENSORS_AD7314
+       tristate "Analog Devices AD7314 and compatibles"
+       depends on SPI && EXPERIMENTAL
+       help
+         If you say yes here you get support for the Analog Devices
+         AD7314, ADT7301 and ADT7302 temperature sensors.
+
+         This driver can also be built as a module. If so, the module
+         will be called ad7314.
+
 config SENSORS_AD7414
        tristate "Analog Devices AD7414"
        depends on I2C && EXPERIMENTAL

diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index dbd8963..8251ce8 100644 (file)
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_SENSORS_W83791D) += w83791d.o
 
 obj-$(CONFIG_SENSORS_ABITUGURU)        += abituguru.o
 obj-$(CONFIG_SENSORS_ABITUGURU3)+= abituguru3.o
+obj-$(CONFIG_SENSORS_AD7314)   += ad7314.o
 obj-$(CONFIG_SENSORS_AD7414)   += ad7414.o
 obj-$(CONFIG_SENSORS_AD7418)   += ad7418.o
 obj-$(CONFIG_SENSORS_ADCXX)    += adcxx.o

diff --git a/drivers/hwmon/ad7314.c b/drivers/hwmon/ad7314.c
new file mode 100644 (file)
index 0000000..318e38e
--- /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");