--- /dev/null
+/*
+ * Dallas Semiconductor DS1682 Elapsed Time Recorder device driver
+ *
+ * Written by: Grant Likely <grant.likely@secretlab.ca>
+ *
+ * Copyright (C) 2007 Secret Lab Technologies Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/*
+ * The DS1682 elapsed timer recorder is a simple device that implements
+ * one elapsed time counter, one event counter, an alarm signal and 10
+ * bytes of general purpose EEPROM.
+ *
+ * This driver provides access to the DS1682 counters and user data via
+ * the sysfs. The following attributes are added to the device node:
+ * elapsed_time (u32): Total elapsed event time in ms resolution
+ * alarm_time (u32): When elapsed time exceeds the value in alarm_time,
+ * then the alarm pin is asserted.
+ * event_count (u16): number of times the event pin has gone low.
+ * eeprom (u8[10]): general purpose EEPROM
+ *
+ * Counter registers and user data are both read/write unless the device
+ * has been write protected. This driver does not support turning off write
+ * protection. Once write protection is turned on, it is impossible to
+ * turn it off again, so I have left the feature out of this driver to avoid
+ * accidental enabling, but it is trivial to add write protect support.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/string.h>
+#include <linux/list.h>
+#include <linux/sysfs.h>
+#include <linux/ctype.h>
+#include <linux/hwmon-sysfs.h>
+
+/* Device registers */
+#define DS1682_REG_CONFIG 0x00
+#define DS1682_REG_ALARM 0x01
+#define DS1682_REG_ELAPSED 0x05
+#define DS1682_REG_EVT_CNTR 0x09
+#define DS1682_REG_EEPROM 0x0b
+#define DS1682_REG_RESET 0x1d
+#define DS1682_REG_WRITE_DISABLE 0x1e
+#define DS1682_REG_WRITE_MEM_DISABLE 0x1f
+
+#define DS1682_EEPROM_SIZE 10
+
+/*
+ * Generic counter attributes
+ */
+static ssize_t ds1682_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
+ struct i2c_client *client = to_i2c_client(dev);
+ __le32 val = 0;
+ int rc;
+
+ dev_dbg(dev, "ds1682_show() called on %s\n", attr->attr.name);
+
+ /* Read the register */
+ rc = i2c_smbus_read_i2c_block_data(client, sattr->index, sattr->nr,
+ (u8 *) & val);
+ if (rc < 0)
+ return -EIO;
+
+ /* Special case: the 32 bit regs are time values with 1/4s
+ * resolution, scale them up to milliseconds */
+ if (sattr->nr == 4)
+ return sprintf(buf, "%llu\n", ((u64) le32_to_cpu(val)) * 250);
+
+ /* Format the output string and return # of bytes */
+ return sprintf(buf, "%li\n", (long)le32_to_cpu(val));
+}
+
+static ssize_t ds1682_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
+ struct i2c_client *client = to_i2c_client(dev);
+ char *endp;
+ u64 val;
+ __le32 val_le;
+ int rc;
+
+ dev_dbg(dev, "ds1682_store() called on %s\n", attr->attr.name);
+
+ /* Decode input */
+ val = simple_strtoull(buf, &endp, 0);
+ if (buf == endp) {
+ dev_dbg(dev, "input string not a number\n");
+ return -EINVAL;
+ }
+
+ /* Special case: the 32 bit regs are time values with 1/4s
+ * resolution, scale input down to quarter-seconds */
+ if (sattr->nr == 4)
+ do_div(val, 250);
+
+ /* write out the value */
+ val_le = cpu_to_le32(val);
+ rc = i2c_smbus_write_i2c_block_data(client, sattr->index, sattr->nr,
+ (u8 *) & val_le);
+ if (rc < 0) {
+ dev_err(dev, "register write failed; reg=0x%x, size=%i\n",
+ sattr->index, sattr->nr);
+ return -EIO;
+ }
+
+ return count;
+}
+
+/*
+ * Simple register attributes
+ */
+static SENSOR_DEVICE_ATTR_2(elapsed_time, S_IRUGO | S_IWUSR, ds1682_show,
+ ds1682_store, 4, DS1682_REG_ELAPSED);
+static SENSOR_DEVICE_ATTR_2(alarm_time, S_IRUGO | S_IWUSR, ds1682_show,
+ ds1682_store, 4, DS1682_REG_ALARM);
+static SENSOR_DEVICE_ATTR_2(event_count, S_IRUGO | S_IWUSR, ds1682_show,
+ ds1682_store, 2, DS1682_REG_EVT_CNTR);
+
+static const struct attribute_group ds1682_group = {
+ .attrs = (struct attribute *[]) {
+ &sensor_dev_attr_elapsed_time.dev_attr.attr,
+ &sensor_dev_attr_alarm_time.dev_attr.attr,
+ &sensor_dev_attr_event_count.dev_attr.attr,
+ NULL,
+ },
+};
+
+/*
+ * User data attribute
+ */
+static ssize_t ds1682_eeprom_read(struct kobject *kobj, char *buf, loff_t off,
+ size_t count)
+{
+ struct i2c_client *client = kobj_to_i2c_client(kobj);
+ int rc;
+
+ dev_dbg(&client->dev, "ds1682_eeprom_read(p=%p, off=%lli, c=%zi)\n",
+ buf, off, count);
+
+ if (off >= DS1682_EEPROM_SIZE)
+ return 0;
+
+ if (off + count > DS1682_EEPROM_SIZE)
+ count = DS1682_EEPROM_SIZE - off;
+
+ rc = i2c_smbus_read_i2c_block_data(client, DS1682_REG_EEPROM + off,
+ count, buf);
+ if (rc < 0)
+ return -EIO;
+
+ return count;
+}
+
+static ssize_t ds1682_eeprom_write(struct kobject *kobj, char *buf, loff_t off,
+ size_t count)
+{
+ struct i2c_client *client = kobj_to_i2c_client(kobj);
+
+ dev_dbg(&client->dev, "ds1682_eeprom_write(p=%p, off=%lli, c=%zi)\n",
+ buf, off, count);
+
+ if (off >= DS1682_EEPROM_SIZE)
+ return -ENOSPC;
+
+ if (off + count > DS1682_EEPROM_SIZE)
+ count = DS1682_EEPROM_SIZE - off;
+
+ /* Write out to the device */
+ if (i2c_smbus_write_i2c_block_data(client, DS1682_REG_EEPROM + off,
+ count, buf) < 0)
+ return -EIO;
+
+ return count;
+}
+
+static struct bin_attribute ds1682_eeprom_attr = {
+ .attr = {
+ .name = "eeprom",
+ .mode = S_IRUGO | S_IWUSR,
+ .owner = THIS_MODULE,
+ },
+ .size = DS1682_EEPROM_SIZE,
+ .read = ds1682_eeprom_read,
+ .write = ds1682_eeprom_write,
+};
+
+/*
+ * Called when a ds1682 device is matched with this driver
+ */
+static int ds1682_probe(struct i2c_client *client)
+{
+ int rc;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_I2C_BLOCK)) {
+ dev_err(&client->dev, "i2c bus does not support the ds1682\n");
+ rc = -ENODEV;
+ goto exit;
+ }
+
+ rc = sysfs_create_group(&client->dev.kobj, &ds1682_group);
+ if (rc)
+ goto exit;
+
+ rc = sysfs_create_bin_file(&client->dev.kobj, &ds1682_eeprom_attr);
+ if (rc)
+ goto exit_bin_attr;
+
+ return 0;
+
+ exit_bin_attr:
+ sysfs_remove_group(&client->dev.kobj, &ds1682_group);
+ exit:
+ return rc;
+}
+
+static int ds1682_remove(struct i2c_client *client)
+{
+ sysfs_remove_bin_file(&client->dev.kobj, &ds1682_eeprom_attr);
+ sysfs_remove_group(&client->dev.kobj, &ds1682_group);
+ return 0;
+}
+
+static struct i2c_driver ds1682_driver = {
+ .driver = {
+ .name = "ds1682",
+ },
+ .probe = ds1682_probe,
+ .remove = ds1682_remove,
+};
+
+static int __init ds1682_init(void)
+{
+ return i2c_add_driver(&ds1682_driver);
+}
+
+static void __exit ds1682_exit(void)
+{
+ i2c_del_driver(&ds1682_driver);
+}
+
+MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
+MODULE_DESCRIPTION("DS1682 Elapsed Time Indicator driver");
+MODULE_LICENSE("GPL");
+
+module_init(ds1682_init);
+module_exit(ds1682_exit);
projects / linux-2.6-omap-h63xx.git / commitdiff