569 строки
14 KiB
C
569 строки
14 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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* This is currently a simple no-alarms driver. If your board has the
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* alarm irq wired up on a ds1337 or ds1339, and you want to use that,
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* then look at the rtc-rs5c372 driver for code to steal...
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*/
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enum ds_type {
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ds_1307,
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ds_1337,
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ds_1338,
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ds_1339,
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ds_1340,
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m41t00,
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// rs5c372 too? different address...
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};
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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 DS1340_BIT_nEOSC 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 DS1307_BIT_12HR 0x40 /* in REG_HOUR */
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# define DS1307_BIT_PM 0x20 /* in REG_HOUR */
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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
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* basic RTC date and time functionality; be careful using them.
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*/
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#define DS1307_REG_CONTROL 0x07 /* or ds1338 */
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# define DS1307_BIT_OUT 0x80
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# define DS1338_BIT_OSF 0x20
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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 DS1340_REG_CONTROL 0x07
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# define DS1340_BIT_OUT 0x80
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# define DS1340_BIT_FT 0x40
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# define DS1340_BIT_CALIB_SIGN 0x20
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# define DS1340_M_CALIBRATION 0x1f
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#define DS1340_REG_FLAG 0x09
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# define DS1340_BIT_OSF 0x80
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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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bool has_nvram;
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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 i2c_client dev;
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struct rtc_device *rtc;
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};
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struct chip_desc {
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char name[9];
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unsigned nvram56:1;
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unsigned alarm:1;
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enum ds_type type;
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};
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static const struct chip_desc chips[] = { {
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.name = "ds1307",
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.type = ds_1307,
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.nvram56 = 1,
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}, {
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.name = "ds1337",
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.type = ds_1337,
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.alarm = 1,
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}, {
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.name = "ds1338",
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.type = ds_1338,
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.nvram56 = 1,
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}, {
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.name = "ds1339",
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.type = ds_1339,
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.alarm = 1,
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}, {
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.name = "ds1340",
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.type = ds_1340,
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}, {
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.name = "m41t00",
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.type = m41t00,
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}, };
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static inline const struct chip_desc *find_chip(const char *s)
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{
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unsigned i;
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for (i = 0; i < ARRAY_SIZE(chips); i++)
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if (strnicmp(s, chips[i].name, sizeof chips[i].name) == 0)
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return &chips[i];
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return NULL;
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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 date and time 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(to_i2c_adapter(ds1307->client->dev.parent),
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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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/* initial clock setting can be undefined */
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return rtc_valid_tm(t);
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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", 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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*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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switch (ds1307->type) {
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case ds_1337:
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case ds_1339:
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buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
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break;
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case 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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break;
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default:
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break;
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}
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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(to_i2c_adapter(ds1307->client->dev.parent),
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&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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/*----------------------------------------------------------------------*/
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#define NVRAM_SIZE 56
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static ssize_t
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ds1307_nvram_read(struct kobject *kobj, struct bin_attribute *attr,
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char *buf, loff_t off, size_t count)
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{
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struct i2c_client *client;
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struct ds1307 *ds1307;
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struct i2c_msg msg[2];
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int result;
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client = kobj_to_i2c_client(kobj);
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ds1307 = i2c_get_clientdata(client);
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if (unlikely(off >= NVRAM_SIZE))
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return 0;
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if ((off + count) > NVRAM_SIZE)
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count = NVRAM_SIZE - off;
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if (unlikely(!count))
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return count;
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msg[0].addr = client->addr;
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msg[0].flags = 0;
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msg[0].len = 1;
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msg[0].buf = buf;
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buf[0] = 8 + off;
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msg[1].addr = client->addr;
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msg[1].flags = I2C_M_RD;
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msg[1].len = count;
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msg[1].buf = buf;
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result = i2c_transfer(to_i2c_adapter(client->dev.parent), msg, 2);
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if (result != 2) {
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dev_err(&client->dev, "%s error %d\n", "nvram read", result);
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return -EIO;
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}
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return count;
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}
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static ssize_t
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ds1307_nvram_write(struct kobject *kobj, struct bin_attribute *attr,
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char *buf, loff_t off, size_t count)
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{
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struct i2c_client *client;
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u8 buffer[NVRAM_SIZE + 1];
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int ret;
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client = kobj_to_i2c_client(kobj);
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if (unlikely(off >= NVRAM_SIZE))
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return -EFBIG;
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if ((off + count) > NVRAM_SIZE)
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count = NVRAM_SIZE - off;
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if (unlikely(!count))
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return count;
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buffer[0] = 8 + off;
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memcpy(buffer + 1, buf, count);
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ret = i2c_master_send(client, buffer, count + 1);
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return (ret < 0) ? ret : (ret - 1);
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}
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static struct bin_attribute nvram = {
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.attr = {
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.name = "nvram",
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.mode = S_IRUGO | S_IWUSR,
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.owner = THIS_MODULE,
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},
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.read = ds1307_nvram_read,
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.write = ds1307_nvram_write,
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.size = NVRAM_SIZE,
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};
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/*----------------------------------------------------------------------*/
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static struct i2c_driver ds1307_driver;
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static int __devinit ds1307_probe(struct i2c_client *client)
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{
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struct ds1307 *ds1307;
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int err = -ENODEV;
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int tmp;
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const struct chip_desc *chip;
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struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
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chip = find_chip(client->name);
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if (!chip) {
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dev_err(&client->dev, "unknown chip type '%s'\n",
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client->name);
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return -ENODEV;
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}
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if (!i2c_check_functionality(adapter,
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I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
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return -EIO;
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if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL)))
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return -ENOMEM;
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ds1307->client = client;
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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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ds1307->type = chip->type;
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switch (ds1307->type) {
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case ds_1337:
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case ds_1339:
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ds1307->reg_addr = DS1337_REG_CONTROL;
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ds1307->msg[1].len = 2;
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/* get registers that the "rtc" read below won't read... */
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tmp = i2c_transfer(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 off? turn it on, so clock can tick. */
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if (ds1307->regs[0] & DS1337_BIT_nEOSC)
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i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
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ds1307->regs[0] & ~DS1337_BIT_nEOSC);
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/* oscillator fault? clear flag, and warn */
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if (ds1307->regs[1] & DS1337_BIT_OSF) {
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i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
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ds1307->regs[1] & ~DS1337_BIT_OSF);
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dev_warn(&client->dev, "SET TIME!\n");
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}
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break;
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default:
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break;
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}
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read_rtc:
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/* read RTC registers */
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tmp = i2c_transfer(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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switch (ds1307->type) {
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case ds_1307:
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case m41t00:
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/* clock halted? turn it on, so clock can tick. */
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if (tmp & DS1307_BIT_CH) {
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i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
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dev_warn(&client->dev, "SET TIME!\n");
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goto read_rtc;
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}
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break;
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case ds_1338:
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/* clock halted? turn it on, so clock can tick. */
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if (tmp & DS1307_BIT_CH)
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i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
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/* oscillator fault? clear flag, and warn */
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if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
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i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
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ds1307->regs[DS1307_REG_CONTROL]
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& ~DS1338_BIT_OSF);
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dev_warn(&client->dev, "SET TIME!\n");
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goto read_rtc;
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}
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break;
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case ds_1340:
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/* clock halted? turn it on, so clock can tick. */
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if (tmp & DS1340_BIT_nEOSC)
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i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
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tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
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if (tmp < 0) {
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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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/* oscillator fault? clear flag, and warn */
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if (tmp & DS1340_BIT_OSF) {
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i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
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dev_warn(&client->dev, "SET TIME!\n");
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}
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break;
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case ds_1337:
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case ds_1339:
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break;
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}
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tmp = ds1307->regs[DS1307_REG_SECS];
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tmp = BCD2BIN(tmp & 0x7f);
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if (tmp > 60)
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goto exit_bad;
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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_bad;
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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_bad;
|
|
|
|
tmp = BCD2BIN(ds1307->regs[DS1307_REG_MONTH] & 0x1f);
|
|
if (tmp == 0 || tmp > 12)
|
|
goto exit_bad;
|
|
|
|
tmp = ds1307->regs[DS1307_REG_HOUR];
|
|
switch (ds1307->type) {
|
|
case ds_1340:
|
|
case m41t00:
|
|
/* NOTE: ignores century bits; fix before deploying
|
|
* systems that will run through year 2100.
|
|
*/
|
|
break;
|
|
default:
|
|
if (!(tmp & DS1307_BIT_12HR))
|
|
break;
|
|
|
|
/* Be sure we're in 24 hour mode. Multi-master systems
|
|
* take note...
|
|
*/
|
|
tmp = BCD2BIN(tmp & 0x1f);
|
|
if (tmp == 12)
|
|
tmp = 0;
|
|
if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
|
|
tmp += 12;
|
|
i2c_smbus_write_byte_data(client,
|
|
DS1307_REG_HOUR,
|
|
BIN2BCD(tmp));
|
|
}
|
|
|
|
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_free;
|
|
}
|
|
|
|
if (chip->nvram56) {
|
|
err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
|
|
if (err == 0) {
|
|
ds1307->has_nvram = true;
|
|
dev_info(&client->dev, "56 bytes nvram\n");
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
|
|
exit_bad:
|
|
dev_dbg(&client->dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
|
|
"bogus register",
|
|
ds1307->regs[0], ds1307->regs[1],
|
|
ds1307->regs[2], ds1307->regs[3],
|
|
ds1307->regs[4], ds1307->regs[5],
|
|
ds1307->regs[6]);
|
|
|
|
exit_free:
|
|
kfree(ds1307);
|
|
return err;
|
|
}
|
|
|
|
static int __devexit ds1307_remove(struct i2c_client *client)
|
|
{
|
|
struct ds1307 *ds1307 = i2c_get_clientdata(client);
|
|
|
|
if (ds1307->has_nvram)
|
|
sysfs_remove_bin_file(&client->dev.kobj, &nvram);
|
|
|
|
rtc_device_unregister(ds1307->rtc);
|
|
kfree(ds1307);
|
|
return 0;
|
|
}
|
|
|
|
static struct i2c_driver ds1307_driver = {
|
|
.driver = {
|
|
.name = "rtc-ds1307",
|
|
.owner = THIS_MODULE,
|
|
},
|
|
.probe = ds1307_probe,
|
|
.remove = __devexit_p(ds1307_remove),
|
|
};
|
|
|
|
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");
|