389 lines
9.9 KiB
C
389 lines
9.9 KiB
C
/*
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* rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.
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*
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* Copyright (C) 2005 James Chapman (ds1337 core)
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* Copyright (C) 2006 David Brownell
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/i2c.h>
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#include <linux/string.h>
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#include <linux/rtc.h>
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#include <linux/bcd.h>
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/* We can't determine type by probing, but if we expect pre-Linux code
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* to have set the chip up as a clock (turning on the oscillator and
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* setting the date and time), Linux can ignore the non-clock features.
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* That's a natural job for a factory or repair bench.
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*
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* If the I2C "force" mechanism is used, we assume the chip is a ds1337.
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* (Much better would be board-specific tables of I2C devices, along with
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* the platform_data drivers would use to sort such issues out.)
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*/
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enum ds_type {
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unknown = 0,
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ds_1307, /* or ds1338, ... */
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ds_1337, /* or ds1339, ... */
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ds_1340, /* or st m41t00, ... */
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// rs5c372 too? different address...
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};
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static unsigned short normal_i2c[] = { 0x68, I2C_CLIENT_END };
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I2C_CLIENT_INSMOD;
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/* RTC registers don't differ much, except for the century flag */
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#define DS1307_REG_SECS 0x00 /* 00-59 */
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# define DS1307_BIT_CH 0x80
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#define DS1307_REG_MIN 0x01 /* 00-59 */
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#define DS1307_REG_HOUR 0x02 /* 00-23, or 1-12{am,pm} */
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# define DS1340_BIT_CENTURY_EN 0x80 /* in REG_HOUR */
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# define DS1340_BIT_CENTURY 0x40 /* in REG_HOUR */
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#define DS1307_REG_WDAY 0x03 /* 01-07 */
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#define DS1307_REG_MDAY 0x04 /* 01-31 */
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#define DS1307_REG_MONTH 0x05 /* 01-12 */
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# define DS1337_BIT_CENTURY 0x80 /* in REG_MONTH */
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#define DS1307_REG_YEAR 0x06 /* 00-99 */
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/* Other registers (control, status, alarms, trickle charge, NVRAM, etc)
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* start at 7, and they differ a lot. Only control and status matter for RTC;
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* be careful using them.
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*/
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#define DS1307_REG_CONTROL 0x07
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# define DS1307_BIT_OUT 0x80
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# define DS1307_BIT_SQWE 0x10
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# define DS1307_BIT_RS1 0x02
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# define DS1307_BIT_RS0 0x01
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#define DS1337_REG_CONTROL 0x0e
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# define DS1337_BIT_nEOSC 0x80
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# define DS1337_BIT_RS2 0x10
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# define DS1337_BIT_RS1 0x08
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# define DS1337_BIT_INTCN 0x04
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# define DS1337_BIT_A2IE 0x02
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# define DS1337_BIT_A1IE 0x01
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#define DS1337_REG_STATUS 0x0f
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# define DS1337_BIT_OSF 0x80
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# define DS1337_BIT_A2I 0x02
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# define DS1337_BIT_A1I 0x01
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#define DS1339_REG_TRICKLE 0x10
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struct ds1307 {
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u8 reg_addr;
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u8 regs[8];
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enum ds_type type;
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struct i2c_msg msg[2];
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struct i2c_client client;
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struct rtc_device *rtc;
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};
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static int ds1307_get_time(struct device *dev, struct rtc_time *t)
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{
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struct ds1307 *ds1307 = dev_get_drvdata(dev);
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int tmp;
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/* read the RTC registers all at once */
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ds1307->msg[1].flags = I2C_M_RD;
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ds1307->msg[1].len = 7;
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tmp = i2c_transfer(ds1307->client.adapter, ds1307->msg, 2);
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if (tmp != 2) {
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dev_err(dev, "%s error %d\n", "read", tmp);
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return -EIO;
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}
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dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
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"read",
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ds1307->regs[0], ds1307->regs[1],
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ds1307->regs[2], ds1307->regs[3],
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ds1307->regs[4], ds1307->regs[5],
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ds1307->regs[6]);
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t->tm_sec = BCD2BIN(ds1307->regs[DS1307_REG_SECS] & 0x7f);
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t->tm_min = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);
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tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
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t->tm_hour = BCD2BIN(tmp);
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t->tm_wday = BCD2BIN(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
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t->tm_mday = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
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tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
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t->tm_mon = BCD2BIN(tmp) - 1;
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/* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
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t->tm_year = BCD2BIN(ds1307->regs[DS1307_REG_YEAR]) + 100;
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dev_dbg(dev, "%s secs=%d, mins=%d, "
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"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
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"read", t->tm_sec, t->tm_min,
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t->tm_hour, t->tm_mday,
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t->tm_mon, t->tm_year, t->tm_wday);
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return 0;
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}
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static int ds1307_set_time(struct device *dev, struct rtc_time *t)
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{
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struct ds1307 *ds1307 = dev_get_drvdata(dev);
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int result;
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int tmp;
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u8 *buf = ds1307->regs;
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dev_dbg(dev, "%s secs=%d, mins=%d, "
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"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
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"write", dt->tm_sec, dt->tm_min,
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dt->tm_hour, dt->tm_mday,
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dt->tm_mon, dt->tm_year, dt->tm_wday);
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*buf++ = 0; /* first register addr */
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buf[DS1307_REG_SECS] = BIN2BCD(t->tm_sec);
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buf[DS1307_REG_MIN] = BIN2BCD(t->tm_min);
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buf[DS1307_REG_HOUR] = BIN2BCD(t->tm_hour);
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buf[DS1307_REG_WDAY] = BIN2BCD(t->tm_wday + 1);
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buf[DS1307_REG_MDAY] = BIN2BCD(t->tm_mday);
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buf[DS1307_REG_MONTH] = BIN2BCD(t->tm_mon + 1);
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/* assume 20YY not 19YY */
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tmp = t->tm_year - 100;
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buf[DS1307_REG_YEAR] = BIN2BCD(tmp);
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if (ds1307->type == ds_1337)
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buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
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else if (ds1307->type == ds_1340)
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buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
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| DS1340_BIT_CENTURY;
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ds1307->msg[1].flags = 0;
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ds1307->msg[1].len = 8;
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dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
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"write", buf[0], buf[1], buf[2], buf[3],
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buf[4], buf[5], buf[6]);
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result = i2c_transfer(ds1307->client.adapter, &ds1307->msg[1], 1);
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if (result != 1) {
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dev_err(dev, "%s error %d\n", "write", tmp);
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return -EIO;
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}
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return 0;
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}
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static const struct rtc_class_ops ds13xx_rtc_ops = {
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.read_time = ds1307_get_time,
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.set_time = ds1307_set_time,
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};
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static struct i2c_driver ds1307_driver;
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static int __devinit
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ds1307_detect(struct i2c_adapter *adapter, int address, int kind)
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{
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struct ds1307 *ds1307;
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int err = -ENODEV;
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struct i2c_client *client;
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int tmp;
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if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL))) {
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err = -ENOMEM;
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goto exit;
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}
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client = &ds1307->client;
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client->addr = address;
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client->adapter = adapter;
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client->driver = &ds1307_driver;
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client->flags = 0;
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i2c_set_clientdata(client, ds1307);
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ds1307->msg[0].addr = client->addr;
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ds1307->msg[0].flags = 0;
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ds1307->msg[0].len = 1;
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ds1307->msg[0].buf = &ds1307->reg_addr;
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ds1307->msg[1].addr = client->addr;
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ds1307->msg[1].flags = I2C_M_RD;
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ds1307->msg[1].len = sizeof(ds1307->regs);
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ds1307->msg[1].buf = ds1307->regs;
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/* HACK: "force" implies "needs ds1337-style-oscillator setup" */
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if (kind >= 0) {
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ds1307->type = ds_1337;
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ds1307->reg_addr = DS1337_REG_CONTROL;
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ds1307->msg[1].len = 2;
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tmp = i2c_transfer(client->adapter, ds1307->msg, 2);
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if (tmp != 2) {
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pr_debug("read error %d\n", tmp);
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err = -EIO;
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goto exit_free;
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}
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ds1307->reg_addr = 0;
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ds1307->msg[1].len = sizeof(ds1307->regs);
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/* oscillator is off; need to turn it on */
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if ((ds1307->regs[0] & DS1337_BIT_nEOSC)
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|| (ds1307->regs[1] & DS1337_BIT_OSF)) {
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printk(KERN_ERR "no ds1337 oscillator code\n");
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goto exit_free;
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}
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} else
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ds1307->type = ds_1307;
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read_rtc:
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/* read RTC registers */
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tmp = i2c_transfer(client->adapter, ds1307->msg, 2);
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if (tmp != 2) {
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pr_debug("read error %d\n", tmp);
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err = -EIO;
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goto exit_free;
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}
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/* minimal sanity checking; some chips (like DS1340) don't
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* specify the extra bits as must-be-zero, but there are
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* still a few values that are clearly out-of-range.
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*/
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tmp = ds1307->regs[DS1307_REG_SECS];
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if (tmp & DS1307_BIT_CH) {
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if (ds1307->type && ds1307->type != ds_1307) {
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pr_debug("not a ds1307?\n");
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goto exit_free;
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}
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ds1307->type = ds_1307;
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/* this partial initialization should work for ds1307,
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* ds1338, ds1340, st m41t00, and more.
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*/
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dev_warn(&client->dev, "oscillator started; SET TIME!\n");
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i2c_smbus_write_byte_data(client, 0, 0);
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goto read_rtc;
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}
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tmp = BCD2BIN(tmp & 0x7f);
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if (tmp > 60)
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goto exit_free;
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tmp = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);
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if (tmp > 60)
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goto exit_free;
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tmp = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
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if (tmp == 0 || tmp > 31)
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goto exit_free;
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tmp = BCD2BIN(ds1307->regs[DS1307_REG_MONTH] & 0x1f);
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if (tmp == 0 || tmp > 12)
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goto exit_free;
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/* force into in 24 hour mode (most chips) or
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* disable century bit (ds1340)
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*/
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tmp = ds1307->regs[DS1307_REG_HOUR];
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if (tmp & (1 << 6)) {
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if (tmp & (1 << 5))
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tmp = BCD2BIN(tmp & 0x1f) + 12;
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else
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tmp = BCD2BIN(tmp);
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i2c_smbus_write_byte_data(client,
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DS1307_REG_HOUR,
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BIN2BCD(tmp));
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}
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/* FIXME chips like 1337 can generate alarm irqs too; those are
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* worth exposing through the API (especially when the irq is
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* wakeup-capable).
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*/
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switch (ds1307->type) {
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case unknown:
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strlcpy(client->name, "unknown", I2C_NAME_SIZE);
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break;
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case ds_1307:
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strlcpy(client->name, "ds1307", I2C_NAME_SIZE);
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break;
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case ds_1337:
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strlcpy(client->name, "ds1337", I2C_NAME_SIZE);
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break;
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case ds_1340:
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strlcpy(client->name, "ds1340", I2C_NAME_SIZE);
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break;
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}
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/* Tell the I2C layer a new client has arrived */
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if ((err = i2c_attach_client(client)))
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goto exit_free;
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ds1307->rtc = rtc_device_register(client->name, &client->dev,
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&ds13xx_rtc_ops, THIS_MODULE);
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if (IS_ERR(ds1307->rtc)) {
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err = PTR_ERR(ds1307->rtc);
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dev_err(&client->dev,
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"unable to register the class device\n");
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goto exit_detach;
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}
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return 0;
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exit_detach:
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i2c_detach_client(client);
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exit_free:
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kfree(ds1307);
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exit:
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return err;
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}
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static int __devinit
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ds1307_attach_adapter(struct i2c_adapter *adapter)
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{
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if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
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return 0;
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return i2c_probe(adapter, &addr_data, ds1307_detect);
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}
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static int __devexit ds1307_detach_client(struct i2c_client *client)
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{
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int err;
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struct ds1307 *ds1307 = i2c_get_clientdata(client);
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rtc_device_unregister(ds1307->rtc);
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if ((err = i2c_detach_client(client)))
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return err;
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kfree(ds1307);
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return 0;
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}
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static struct i2c_driver ds1307_driver = {
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.driver = {
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.name = "ds1307",
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.owner = THIS_MODULE,
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},
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.attach_adapter = ds1307_attach_adapter,
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.detach_client = __devexit_p(ds1307_detach_client),
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};
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static int __init ds1307_init(void)
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{
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return i2c_add_driver(&ds1307_driver);
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}
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module_init(ds1307_init);
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static void __exit ds1307_exit(void)
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{
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i2c_del_driver(&ds1307_driver);
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}
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module_exit(ds1307_exit);
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MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
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MODULE_LICENSE("GPL");
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