| /* |
| * 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... |
| * |
| * 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, |
| ds_1337, |
| ds_1338, |
| ds_1339, |
| ds_1340, |
| 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 DS1340_BIT_nEOSC 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 |
| * 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; |
| 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 { |
| char name[9]; |
| unsigned nvram56:1; |
| unsigned alarm:1; |
| enum ds_type type; |
| }; |
| |
| static const struct chip_desc chips[] = { { |
| .name = "ds1307", |
| .type = ds_1307, |
| .nvram56 = 1, |
| }, { |
| .name = "ds1337", |
| .type = ds_1337, |
| .alarm = 1, |
| }, { |
| .name = "ds1338", |
| .type = ds_1338, |
| .nvram56 = 1, |
| }, { |
| .name = "ds1339", |
| .type = ds_1339, |
| .alarm = 1, |
| }, { |
| .name = "ds1340", |
| .type = ds_1340, |
| }, { |
| .name = "m41t00", |
| .type = m41t00, |
| }, }; |
| |
| static inline const struct chip_desc *find_chip(const char *s) |
| { |
| unsigned i; |
| |
| for (i = 0; i < ARRAY_SIZE(chips); i++) |
| if (strnicmp(s, chips[i].name, sizeof chips[i].name) == 0) |
| return &chips[i]; |
| return NULL; |
| } |
| |
| 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, |
| }; |
| |
| 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; |
| const struct chip_desc *chip; |
| |
| if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL))) { |
| err = -ENOMEM; |
| goto exit; |
| } |
| |
| /* REVISIT: pending driver model conversion, set up "client" |
| * ourselves, and use a hack to determine the RTC type (instead |
| * of reading the client->name we're given) |
| */ |
| client = &ds1307->dev; |
| client->addr = address; |
| client->adapter = adapter; |
| client->driver = &ds1307_driver; |
| |
| /* HACK: "force" implies "needs ds1337-style-oscillator setup", and |
| * that's the only kind of chip setup we'll know about. Until the |
| * driver model conversion, here's where to add any board-specific |
| * code to say what kind of chip is present... |
| */ |
| if (kind >= 0) |
| chip = find_chip("ds1337"); |
| else |
| chip = find_chip("ds1307"); |
| strlcpy(client->name, chip->name, I2C_NAME_SIZE); |
| |
| 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 = chip->type; |
| |
| 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_1340: |
| /* FIXME read register with DS1340_BIT_OSF, use that to |
| * trigger the "set time" warning (*after* restarting the |
| * oscillator!) instead of this weaker ds1307/m41t00 test. |
| */ |
| 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[DS1337_REG_CONTROL] |
| & ~DS1338_BIT_OSF); |
| dev_warn(&client->dev, "SET TIME!\n"); |
| goto read_rtc; |
| } |
| break; |
| default: |
| break; |
| } |
| |
| tmp = ds1307->regs[DS1307_REG_SECS]; |
| 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) |
| * |
| * REVISIT forcing 24 hour mode can prevent multi-master |
| * configs from sharing this RTC ... don't do this. |
| * The clock needs to be reset after changing it, too... |
| */ |
| 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)); |
| } |
| |
| /* 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"); |