/* * rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips. * * Copyright (C) 2005 James Chapman (ds1337 core) * Copyright (C) 2006 David Brownell * * 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. */ #include <linux/module.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/i2c.h> #include <linux/string.h> #include <linux/rtc.h> #include <linux/bcd.h> /* We can't determine type by probing, but if we expect pre-Linux code * to have set the chip up as a clock (turning on the oscillator and * setting the date and time), Linux can ignore the non-clock features. * That's a natural job for a factory or repair bench. * * This is currently a simple no-alarms driver. If your board has the * alarm irq wired up on a ds1337 or ds1339, and you want to use that, * then look at the rtc-rs5c372 driver for code to steal... */ enum ds_type { ds_1307, ds_1337, ds_1338, ds_1339, ds_1340, m41t00, // rs5c372 too? different address... }; /* RTC registers don't differ much, except for the century flag */ #define DS1307_REG_SECS 0x00 /* 00-59 */ # define DS1307_BIT_CH 0x80 # define DS1340_BIT_nEOSC 0x80 #define DS1307_REG_MIN 0x01 /* 00-59 */ #define DS1307_REG_HOUR 0x02 /* 00-23, or 1-12{am,pm} */ # define DS1307_BIT_12HR 0x40 /* in REG_HOUR */ # define DS1307_BIT_PM 0x20 /* in REG_HOUR */ # define DS1340_BIT_CENTURY_EN 0x80 /* in REG_HOUR */ # define DS1340_BIT_CENTURY 0x40 /* in REG_HOUR */ #define DS1307_REG_WDAY 0x03 /* 01-07 */ #define DS1307_REG_MDAY 0x04 /* 01-31 */ #define DS1307_REG_MONTH 0x05 /* 01-12 */ # define DS1337_BIT_CENTURY 0x80 /* in REG_MONTH */ #define DS1307_REG_YEAR 0x06 /* 00-99 */ /* Other registers (control, status, alarms, trickle charge, NVRAM, etc) * start at 7, and they differ a LOT. Only control and status matter for * basic RTC date and time functionality; be careful using them. */ #define DS1307_REG_CONTROL 0x07 /* or ds1338 */ # define DS1307_BIT_OUT 0x80 # define DS1338_BIT_OSF 0x20 # define DS1307_BIT_SQWE 0x10 # define DS1307_BIT_RS1 0x02 # define DS1307_BIT_RS0 0x01 #define DS1337_REG_CONTROL 0x0e # define DS1337_BIT_nEOSC 0x80 # define DS1337_BIT_RS2 0x10 # define DS1337_BIT_RS1 0x08 # define DS1337_BIT_INTCN 0x04 # define DS1337_BIT_A2IE 0x02 # define DS1337_BIT_A1IE 0x01 #define DS1340_REG_CONTROL 0x07 # define DS1340_BIT_OUT 0x80 # define DS1340_BIT_FT 0x40 # define DS1340_BIT_CALIB_SIGN 0x20 # define DS1340_M_CALIBRATION 0x1f #define DS1340_REG_FLAG 0x09 # define DS1340_BIT_OSF 0x80 #define DS1337_REG_STATUS 0x0f # define DS1337_BIT_OSF 0x80 # define DS1337_BIT_A2I 0x02 # define DS1337_BIT_A1I 0x01 #define DS1339_REG_TRICKLE 0x10 struct ds1307 { u8 reg_addr; bool has_nvram; u8 regs[8]; enum ds_type type; struct i2c_msg msg[2]; struct i2c_client *client; struct i2c_client dev; struct rtc_device *rtc; }; struct chip_desc { unsigned nvram56:1; unsigned alarm:1; }; static const struct chip_desc chips[] = { [ds_1307] = { .nvram56 = 1, }, [ds_1337] = { .alarm = 1, }, [ds_1338] = { .nvram56 = 1, }, [ds_1339] = { .alarm = 1, }, [ds_1340] = { }, [m41t00] = { }, }; static const struct i2c_device_id ds1307_id[] = { { "ds1307", ds_1307 }, { "ds1337", ds_1337 }, { "ds1338", ds_1338 }, { "ds1339", ds_1339 }, { "ds1340", ds_1340 }, { "m41t00", m41t00 }, { } }; MODULE_DEVICE_TABLE(i2c, ds1307_id); static int ds1307_get_time(struct device *dev, struct rtc_time *t) { struct ds1307 *ds1307 = dev_get_drvdata(dev); int tmp; /* read the RTC date and time registers all at once */ ds1307->msg[1].flags = I2C_M_RD; ds1307->msg[1].len = 7; tmp = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent), ds1307->msg, 2); if (tmp != 2) { dev_err(dev, "%s error %d\n", "read", tmp); return -EIO; } dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n", "read", ds1307->regs[0], ds1307->regs[1], ds1307->regs[2], ds1307->regs[3], ds1307->regs[4], ds1307->regs[5], ds1307->regs[6]); t->tm_sec = BCD2BIN(ds1307->regs[DS1307_REG_SECS] & 0x7f); t->tm_min = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f); tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f; t->tm_hour = BCD2BIN(tmp); t->tm_wday = BCD2BIN(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1; t->tm_mday = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f); tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f; t->tm_mon = BCD2BIN(tmp) - 1; /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */ t->tm_year = BCD2BIN(ds1307->regs[DS1307_REG_YEAR]) + 100; dev_dbg(dev, "%s secs=%d, mins=%d, " "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n", "read", t->tm_sec, t->tm_min, t->tm_hour, t->tm_mday, t->tm_mon, t->tm_year, t->tm_wday); /* initial clock setting can be undefined */ return rtc_valid_tm(t); } static int ds1307_set_time(struct device *dev, struct rtc_time *t) { struct ds1307 *ds1307 = dev_get_drvdata(dev); int result; int tmp; u8 *buf = ds1307->regs; dev_dbg(dev, "%s secs=%d, mins=%d, " "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n", "write", t->tm_sec, t->tm_min, t->tm_hour, t->tm_mday, t->tm_mon, t->tm_year, t->tm_wday); *buf++ = 0; /* first register addr */ buf[DS1307_REG_SECS] = BIN2BCD(t->tm_sec); buf[DS1307_REG_MIN] = BIN2BCD(t->tm_min); buf[DS1307_REG_HOUR] = BIN2BCD(t->tm_hour); buf[DS1307_REG_WDAY] = BIN2BCD(t->tm_wday + 1); buf[DS1307_REG_MDAY] = BIN2BCD(t->tm_mday); buf[DS1307_REG_MONTH] = BIN2BCD(t->tm_mon + 1); /* assume 20YY not 19YY */ tmp = t->tm_year - 100; buf[DS1307_REG_YEAR] = BIN2BCD(tmp); switch (ds1307->type) { case ds_1337: case ds_1339: buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY; break; case ds_1340: buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN | DS1340_BIT_CENTURY; break; default: break; } ds1307->msg[1].flags = 0; ds1307->msg[1].len = 8; dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n", "write", buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6]); result = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent), &ds1307->msg[1], 1); if (result != 1) { dev_err(dev, "%s error %d\n", "write", tmp); return -EIO; } return 0; } static const struct rtc_class_ops ds13xx_rtc_ops = { .read_time = ds1307_get_time, .set_time = ds1307_set_time, }; /*----------------------------------------------------------------------*/ #define NVRAM_SIZE 56 static ssize_t ds1307_nvram_read(struct kobject *kobj, struct bin_attribute *attr, char *buf, loff_t off, size_t count) { struct i2c_client *client; struct ds1307 *ds1307; struct i2c_msg msg[2]; int result; client = kobj_to_i2c_client(kobj); ds1307 = i2c_get_clientdata(client); if (unlikely(off >= NVRAM_SIZE)) return 0; if ((off + count) > NVRAM_SIZE) count = NVRAM_SIZE - off; if (unlikely(!count)) return count; msg[0].addr = client->addr; msg[0].flags = 0; msg[0].len = 1; msg[0].buf = buf; buf[0] = 8 + off; msg[1].addr = client->addr; msg[1].flags = I2C_M_RD; msg[1].len = count; msg[1].buf = buf; result = i2c_transfer(to_i2c_adapter(client->dev.parent), msg, 2); if (result != 2) { dev_err(&client->dev, "%s error %d\n", "nvram read", result); return -EIO; } return count; } static ssize_t ds1307_nvram_write(struct kobject *kobj, struct bin_attribute *attr, char *buf, loff_t off, size_t count) { struct i2c_client *client; u8 buffer[NVRAM_SIZE + 1]; int ret; client = kobj_to_i2c_client(kobj); if (unlikely(off >= NVRAM_SIZE)) return -EFBIG; if ((off + count) > NVRAM_SIZE) count = NVRAM_SIZE - off; if (unlikely(!count)) return count; buffer[0] = 8 + off; memcpy(buffer + 1, buf, count); ret = i2c_master_send(client, buffer, count + 1); return (ret < 0) ? ret : (ret - 1); } static struct bin_attribute nvram = { .attr = { .name = "nvram", .mode = S_IRUGO | S_IWUSR, .owner = THIS_MODULE, }, .read = ds1307_nvram_read, .write = ds1307_nvram_write, .size = NVRAM_SIZE, }; /*----------------------------------------------------------------------*/ static struct i2c_driver ds1307_driver; static int __devinit ds1307_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct ds1307 *ds1307; int err = -ENODEV; int tmp; const struct chip_desc *chip = &chips[id->driver_data]; struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); if (!i2c_check_functionality(adapter, I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) return -EIO; if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL))) return -ENOMEM; ds1307->client = client; i2c_set_clientdata(client, ds1307); ds1307->msg[0].addr = client->addr; ds1307->msg[0].flags = 0; ds1307->msg[0].len = 1; ds1307->msg[0].buf = &ds1307->reg_addr; ds1307->msg[1].addr = client->addr; ds1307->msg[1].flags = I2C_M_RD; ds1307->msg[1].len = sizeof(ds1307->regs); ds1307->msg[1].buf = ds1307->regs; ds1307->type = id->driver_data; switch (ds1307->type) { case ds_1337: case ds_1339: ds1307->reg_addr = DS1337_REG_CONTROL; ds1307->msg[1].len = 2; /* get registers that the "rtc" read below won't read... */ tmp = i2c_transfer(adapter, ds1307->msg, 2); if (tmp != 2) { pr_debug("read error %d\n", tmp); err = -EIO; goto exit_free; } ds1307->reg_addr = 0; ds1307->msg[1].len = sizeof(ds1307->regs); /* oscillator off? turn it on, so clock can tick. */ if (ds1307->regs[0] & DS1337_BIT_nEOSC) i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ds1307->regs[0] & ~DS1337_BIT_nEOSC); /* oscillator fault? clear flag, and warn */ if (ds1307->regs[1] & DS1337_BIT_OSF) { i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, ds1307->regs[1] & ~DS1337_BIT_OSF); dev_warn(&client->dev, "SET TIME!\n"); } break; default: break; } read_rtc: /* read RTC registers */ tmp = i2c_transfer(adapter, ds1307->msg, 2); if (tmp != 2) { pr_debug("read error %d\n", tmp); err = -EIO; goto exit_free; } /* minimal sanity checking; some chips (like DS1340) don't * specify the extra bits as must-be-zero, but there are * still a few values that are clearly out-of-range. */ tmp = ds1307->regs[DS1307_REG_SECS]; switch (ds1307->type) { case ds_1307: case m41t00: /* clock halted? turn it on, so clock can tick. */ if (tmp & DS1307_BIT_CH) { i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0); dev_warn(&client->dev, "SET TIME!\n"); goto read_rtc; } break; case ds_1338: /* clock halted? turn it on, so clock can tick. */ if (tmp & DS1307_BIT_CH) i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0); /* oscillator fault? clear flag, and warn */ if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) { i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL, ds1307->regs[DS1307_REG_CONTROL] & ~DS1338_BIT_OSF); dev_warn(&client->dev, "SET TIME!\n"); goto read_rtc; } break; case ds_1340: /* clock halted? turn it on, so clock can tick. */ if (tmp & DS1340_BIT_nEOSC) i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0); tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG); if (tmp < 0) { pr_debug("read error %d\n", tmp); err = -EIO; goto exit_free; } /* oscillator fault? clear flag, and warn */ if (tmp & DS1340_BIT_OSF) { i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0); dev_warn(&client->dev, "SET TIME!\n"); } break; case ds_1337: case ds_1339: break; } tmp = ds1307->regs[DS1307_REG_SECS]; tmp = BCD2BIN(tmp & 0x7f); if (tmp > 60) goto exit_bad; tmp = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f); if (tmp > 60) goto exit_bad; tmp = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f); if (tmp == 0 || tmp > 31) goto exit_bad; tmp = BCD2BIN(ds1307->regs[DS1307_REG_MONTH] & 0x1f); if (tmp == 0 || tmp > 12) goto exit_bad; tmp = ds1307->regs[DS1307_REG_HOUR]; switch (ds1307->type) { case ds_1340: case m41t00: /* NOTE: ignores century bits; fix before deploying * systems that will run through year 2100. */ break; default: if (!(tmp & DS1307_BIT_12HR)) break; /* Be sure we're in 24 hour mode. Multi-master systems * take note... */ tmp = BCD2BIN(tmp & 0x1f); if (tmp == 12) tmp = 0; if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM) tmp += 12; i2c_smbus_write_byte_data(client, DS1307_REG_HOUR, BIN2BCD(tmp)); } ds1307->rtc = rtc_device_register(client->name, &client->dev, &ds13xx_rtc_ops, THIS_MODULE); if (IS_ERR(ds1307->rtc)) { err = PTR_ERR(ds1307->rtc); dev_err(&client->dev, "unable to register the class device\n"); goto exit_free; } if (chip->nvram56) { err = sysfs_create_bin_file(&client->dev.kobj, &nvram); if (err == 0) { ds1307->has_nvram = true; dev_info(&client->dev, "56 bytes nvram\n"); } } return 0; exit_bad: dev_dbg(&client->dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n", "bogus register", ds1307->regs[0], ds1307->regs[1], ds1307->regs[2], ds1307->regs[3], ds1307->regs[4], ds1307->regs[5], ds1307->regs[6]); exit_free: kfree(ds1307); return err; } static int __devexit ds1307_remove(struct i2c_client *client) { struct ds1307 *ds1307 = i2c_get_clientdata(client); if (ds1307->has_nvram) sysfs_remove_bin_file(&client->dev.kobj, &nvram); rtc_device_unregister(ds1307->rtc); kfree(ds1307); return 0; } static struct i2c_driver ds1307_driver = { .driver = { .name = "rtc-ds1307", .owner = THIS_MODULE, }, .probe = ds1307_probe, .remove = __devexit_p(ds1307_remove), .id_table = ds1307_id, }; static int __init ds1307_init(void) { return i2c_add_driver(&ds1307_driver); } module_init(ds1307_init); static void __exit ds1307_exit(void) { i2c_del_driver(&ds1307_driver); } module_exit(ds1307_exit); MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips"); MODULE_LICENSE("GPL");