diff options
Diffstat (limited to 'drivers/rtc/rtc-ds1672.c')
| -rw-r--r-- | drivers/rtc/rtc-ds1672.c | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-ds1672.c b/drivers/rtc/rtc-ds1672.c new file mode 100644 index 0000000..358695a --- /dev/null +++ b/drivers/rtc/rtc-ds1672.c @@ -0,0 +1,233 @@ +/* + * An rtc/i2c driver for the Dallas DS1672 + * Copyright 2005 Alessandro Zummo + * + * 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/i2c.h> +#include <linux/rtc.h> + +#define DRV_VERSION "0.2" + +/* Addresses to scan: none. This chip cannot be detected. */ +static unsigned short normal_i2c[] = { I2C_CLIENT_END }; + +/* Insmod parameters */ +I2C_CLIENT_INSMOD; + +/* Registers */ + +#define DS1672_REG_CNT_BASE 0 +#define DS1672_REG_CONTROL 4 +#define DS1672_REG_TRICKLE 5 + + +/* Prototypes */ +static int ds1672_probe(struct i2c_adapter *adapter, int address, int kind); + +/* + * In the routines that deal directly with the ds1672 hardware, we use + * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch + * Epoch is initialized as 2000. Time is set to UTC. + */ +static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm) +{ + unsigned long time; + unsigned char addr = DS1672_REG_CNT_BASE; + unsigned char buf[4]; + + struct i2c_msg msgs[] = { + { client->addr, 0, 1, &addr }, /* setup read ptr */ + { client->addr, I2C_M_RD, 4, buf }, /* read date */ + }; + + /* read date registers */ + if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { + dev_err(&client->dev, "%s: read error\n", __FUNCTION__); + return -EIO; + } + + dev_dbg(&client->dev, + "%s: raw read data - counters=%02x,%02x,%02x,%02x\n" + __FUNCTION__, + buf[0], buf[1], buf[2], buf[3]); + + time = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0]; + + rtc_time_to_tm(time, tm); + + dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " + "mday=%d, mon=%d, year=%d, wday=%d\n", + __FUNCTION__, + tm->tm_sec, tm->tm_min, tm->tm_hour, + tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); + + return 0; +} + +static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs) +{ + int xfer; + unsigned char buf[5]; + + buf[0] = DS1672_REG_CNT_BASE; + buf[1] = secs & 0x000000FF; + buf[2] = (secs & 0x0000FF00) >> 8; + buf[3] = (secs & 0x00FF0000) >> 16; + buf[4] = (secs & 0xFF000000) >> 24; + + xfer = i2c_master_send(client, buf, 5); + if (xfer != 5) { + dev_err(&client->dev, "%s: send: %d\n", __FUNCTION__, xfer); + return -EIO; + } + + return 0; +} + +static int ds1672_set_datetime(struct i2c_client *client, struct rtc_time *tm) +{ + unsigned long secs; + + dev_dbg(&client->dev, + "%s: secs=%d, mins=%d, hours=%d, ", + "mday=%d, mon=%d, year=%d, wday=%d\n", + __FUNCTION__, + tm->tm_sec, tm->tm_min, tm->tm_hour, + tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); + + rtc_tm_to_time(tm, &secs); + + return ds1672_set_mmss(client, secs); +} + +static int ds1672_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + return ds1672_get_datetime(to_i2c_client(dev), tm); +} + +static int ds1672_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + return ds1672_set_datetime(to_i2c_client(dev), tm); +} + +static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs) +{ + return ds1672_set_mmss(to_i2c_client(dev), secs); +} + +static struct rtc_class_ops ds1672_rtc_ops = { + .read_time = ds1672_rtc_read_time, + .set_time = ds1672_rtc_set_time, + .set_mmss = ds1672_rtc_set_mmss, +}; + +static int ds1672_attach(struct i2c_adapter *adapter) +{ + dev_dbg(&adapter->dev, "%s\n", __FUNCTION__); + return i2c_probe(adapter, &addr_data, ds1672_probe); +} + +static int ds1672_detach(struct i2c_client *client) +{ + int err; + struct rtc_device *rtc = i2c_get_clientdata(client); + + dev_dbg(&client->dev, "%s\n", __FUNCTION__); + + if (rtc) + rtc_device_unregister(rtc); + + if ((err = i2c_detach_client(client))) + return err; + + kfree(client); + + return 0; +} + +static struct i2c_driver ds1672_driver = { + .driver = { + .name = "ds1672", + }, + .id = I2C_DRIVERID_DS1672, + .attach_adapter = &ds1672_attach, + .detach_client = &ds1672_detach, +}; + +static int ds1672_probe(struct i2c_adapter *adapter, int address, int kind) +{ + int err = 0; + struct i2c_client *client; + struct rtc_device *rtc; + + dev_dbg(&adapter->dev, "%s\n", __FUNCTION__); + + if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) { + err = -ENODEV; + goto exit; + } + + if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) { + err = -ENOMEM; + goto exit; + } + + /* I2C client */ + client->addr = address; + client->driver = &ds1672_driver; + client->adapter = adapter; + + strlcpy(client->name, ds1672_driver.driver.name, I2C_NAME_SIZE); + + /* Inform the i2c layer */ + if ((err = i2c_attach_client(client))) + goto exit_kfree; + + dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); + + rtc = rtc_device_register(ds1672_driver.driver.name, &client->dev, + &ds1672_rtc_ops, THIS_MODULE); + + if (IS_ERR(rtc)) { + err = PTR_ERR(rtc); + dev_err(&client->dev, + "unable to register the class device\n"); + goto exit_detach; + } + + i2c_set_clientdata(client, rtc); + + return 0; + +exit_detach: + i2c_detach_client(client); + +exit_kfree: + kfree(client); + +exit: + return err; +} + +static int __init ds1672_init(void) +{ + return i2c_add_driver(&ds1672_driver); +} + +static void __exit ds1672_exit(void) +{ + i2c_del_driver(&ds1672_driver); +} + +MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); +MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver"); +MODULE_LICENSE("GPL"); +MODULE_VERSION(DRV_VERSION); + +module_init(ds1672_init); +module_exit(ds1672_exit); |
