/* * 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 #include #include #include #include #include #include /* 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. * * If the I2C "force" mechanism is used, we assume the chip is a ds1337. * (Much better would be board-specific tables of I2C devices, along with * the platform_data drivers would use to sort such issues out.) */ enum ds_type { unknown = 0, ds_1307, /* or ds1338, ... */ ds_1337, /* or ds1339, ... */ ds_1340, /* or st m41t00, ... */ // rs5c372 too? different address... }; static unsigned short normal_i2c[] = { 0x68, I2C_CLIENT_END }; I2C_CLIENT_INSMOD; /* RTC registers don't differ much, except for the century flag */ #define DS1307_REG_SECS 0x00 /* 00-59 */ # define DS1307_BIT_CH 0x80 #define DS1307_REG_MIN 0x01 /* 00-59 */ #define DS1307_REG_HOUR 0x02 /* 00-23, or 1-12{am,pm} */ # 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 RTC; * be careful using them. */ #define DS1307_REG_CONTROL 0x07 # define DS1307_BIT_OUT 0x80 # 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 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; u8 regs[8]; enum ds_type type; struct i2c_msg msg[2]; struct i2c_client client; struct rtc_device *rtc; }; static int ds1307_get_time(struct device *dev, struct rtc_time *t) { struct ds1307 *ds1307 = dev_get_drvdata(dev); int tmp; /* read the RTC registers all at once */ ds1307->msg[1].flags = I2C_M_RD; ds1307->msg[1].len = 7; tmp = i2c_transfer(ds1307->client.adapter, 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); return 0; } 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); if (ds1307->type == ds_1337) buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY; else if (ds1307->type == ds_1340) buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN | DS1340_BIT_CENTURY; 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(ds1307->client.adapter, &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, }; static struct i2c_driver ds1307_driver; static int __devinit ds1307_detect(struct i2c_adapter *adapter, int address, int kind) { struct ds1307 *ds1307; int err = -ENODEV; struct i2c_client *client; int tmp; if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL))) { err = -ENOMEM; goto exit; } client = &ds1307->client; client->addr = address; client->adapter = adapter; client->driver = &ds1307_driver; client->flags = 0; 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; /* HACK: "force" implies "needs ds1337-style-oscillator setup" */ if (kind >= 0) { ds1307->type = ds_1337; ds1307->reg_addr = DS1337_REG_CONTROL; ds1307->msg[1].len = 2; tmp = i2c_transfer(client->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 is off; need to turn it on */ if ((ds1307->regs[0] & DS1337_BIT_nEOSC) || (ds1307->regs[1] & DS1337_BIT_OSF)) { printk(KERN_ERR "no ds1337 oscillator code\n"); goto exit_free; } } else ds1307->type = ds_1307; read_rtc: /* read RTC registers */ tmp = i2c_transfer(client->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]; if (tmp & DS1307_BIT_CH) { if (ds1307->type && ds1307->type != ds_1307) { pr_debug("not a ds1307?\n"); goto exit_free; } ds1307->type = ds_1307; /* this partial initialization should work for ds1307, * ds1338, ds1340, st m41t00, and more. */ dev_warn(&client->dev, "oscillator started; SET TIME!\n"); i2c_smbus_write_byte_data(client, 0, 0); goto read_rtc; } tmp = BCD2BIN(tmp & 0x7f); if (tmp > 60) goto exit_free; tmp = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f); if (tmp > 60) goto exit_free; tmp = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f); if (tmp == 0 || tmp > 31) goto exit_free; tmp = BCD2BIN(ds1307->regs[DS1307_REG_MONTH] & 0x1f); if (tmp == 0 || tmp > 12) goto exit_free; /* force into in 24 hour mode (most chips) or * disable century bit (ds1340) */ tmp = ds1307->regs[DS1307_REG_HOUR]; if (tmp & (1 << 6)) { if (tmp & (1 << 5)) tmp = BCD2BIN(tmp & 0x1f) + 12; else tmp = BCD2BIN(tmp); i2c_smbus_write_byte_data(client, DS1307_REG_HOUR, BIN2BCD(tmp)); } /* FIXME chips like 1337 can generate alarm irqs too; those are * worth exposing through the API (especially when the irq is * wakeup-capable). */ switch (ds1307->type) { case unknown: strlcpy(client->name, "unknown", I2C_NAME_SIZE); break; case ds_1307: strlcpy(client->name, "ds1307", I2C_NAME_SIZE); break; case ds_1337: strlcpy(client->name, "ds1337", I2C_NAME_SIZE); break; case ds_1340: strlcpy(client->name, "ds1340", I2C_NAME_SIZE); break; } /* Tell the I2C layer a new client has arrived */ if ((err = i2c_attach_client(client))) goto exit_free; 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_detach; } return 0; exit_detach: i2c_detach_client(client); exit_free: kfree(ds1307); exit: return err; } static int __devinit ds1307_attach_adapter(struct i2c_adapter *adapter) { if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) return 0; return i2c_probe(adapter, &addr_data, ds1307_detect); } static int __devexit ds1307_detach_client(struct i2c_client *client) { int err; struct ds1307 *ds1307 = i2c_get_clientdata(client); rtc_device_unregister(ds1307->rtc); if ((err = i2c_detach_client(client))) return err; kfree(ds1307); return 0; } static struct i2c_driver ds1307_driver = { .driver = { .name = "ds1307", .owner = THIS_MODULE, }, .attach_adapter = ds1307_attach_adapter, .detach_client = __devexit_p(ds1307_detach_client), }; 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");