/* * 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", ((unsigned long long)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, struct bin_attribute *attr, 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, struct bin_attribute *attr, 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, }, .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, const struct i2c_device_id *id) { 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 const struct i2c_device_id ds1682_id[] = { { "ds1682", 0 }, { } }; MODULE_DEVICE_TABLE(i2c, ds1682_id); static struct i2c_driver ds1682_driver = { .driver = { .name = "ds1682", }, .probe = ds1682_probe, .remove = ds1682_remove, .id_table = ds1682_id, }; 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);