diff options
| -rw-r--r-- | drivers/rtc/Kconfig | 18 | ||||
| -rw-r--r-- | drivers/rtc/Makefile | 1 | ||||
| -rw-r--r-- | drivers/rtc/rtc-ds1307.c | 388 |
3 files changed, 407 insertions, 0 deletions
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index 875ff5e5792..9e249650baf 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -86,6 +86,24 @@ config RTC_DRV_X1205 This driver can also be built as a module. If so, the module will be called rtc-x1205. +config RTC_DRV_DS1307 + tristate "Dallas/Maxim DS1307 and similar I2C RTC chips" + depends on RTC_CLASS && I2C + help + If you say yes here you get support for various compatible RTC + chips (often with battery backup) connected with I2C. This driver + should handle DS1307, DS1337, DS1338, DS1339, DS1340, ST M41T00, + and probably other chips. In some cases the RTC must already + have been initialized (by manufacturing or a bootloader). + + The first seven registers on these chips hold an RTC, and other + registers may add features such as NVRAM, a trickle charger for + the RTC/NVRAM backup power, and alarms. This driver may not + expose all those available chip features. + + This driver can also be built as a module. If so, the module + will be called rtc-ds1307. + config RTC_DRV_DS1672 tristate "Dallas/Maxim DS1672" depends on RTC_CLASS && I2C diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile index 1b3f32ecec8..ca8bed53079 100644 --- a/drivers/rtc/Makefile +++ b/drivers/rtc/Makefile @@ -13,6 +13,7 @@ obj-$(CONFIG_RTC_INTF_DEV) += rtc-dev.o obj-$(CONFIG_RTC_DRV_X1205) += rtc-x1205.o obj-$(CONFIG_RTC_DRV_TEST) += rtc-test.o +obj-$(CONFIG_RTC_DRV_DS1307) += rtc-ds1307.o obj-$(CONFIG_RTC_DRV_DS1672) += rtc-ds1672.o obj-$(CONFIG_RTC_DRV_PCF8563) += rtc-pcf8563.o obj-$(CONFIG_RTC_DRV_RS5C372) += rtc-rs5c372.o diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c new file mode 100644 index 00000000000..e8afb938478 --- /dev/null +++ b/drivers/rtc/rtc-ds1307.c @@ -0,0 +1,388 @@ +/* + * 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. + * + * 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", dt->tm_sec, dt->tm_min, + dt->tm_hour, dt->tm_mday, + dt->tm_mon, dt->tm_year, dt->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 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"); |