348 lines
9.1 KiB
C
348 lines
9.1 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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* This code was ported from linux-3.15 kernel by Antony Pavlov.
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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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* Copyright (C) 2009 Matthias Fuchs (rx8025 support)
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* Copyright (C) 2012 Bertrand Achard (nvram access fixes)
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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 <common.h>
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#include <init.h>
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#include <driver.h>
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#include <xfuncs.h>
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#include <errno.h>
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#include <i2c/i2c.h>
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#include <rtc.h>
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#include <linux/rtc.h>
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#include <linux/bcd.h>
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/*
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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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enum ds_type {
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ds_1307,
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ds_1338,
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last_ds_type /* always last */
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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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/*
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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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struct ds1307 {
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struct rtc_device rtc;
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u8 offset; /* register's offset */
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u8 regs[11];
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enum ds_type type;
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unsigned long flags;
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struct i2c_client *client;
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s32 (*read_block_data)(const struct i2c_client *client, u8 command,
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u8 length, u8 *values);
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s32 (*write_block_data)(const struct i2c_client *client, u8 command,
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u8 length, const u8 *values);
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};
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static struct platform_device_id ds1307_id[] = {
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{ "ds1307", ds_1307 },
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{ "ds1338", ds_1338 },
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{ "pt7c4338", ds_1307 },
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{ }
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};
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/*----------------------------------------------------------------------*/
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#define BLOCK_DATA_MAX_TRIES 10
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static s32 ds1307_read_block_data_once(const struct i2c_client *client,
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u8 command, u8 length, u8 *values)
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{
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s32 i, data;
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for (i = 0; i < length; i++) {
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data = i2c_smbus_read_byte_data(client, command + i);
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if (data < 0)
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return data;
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values[i] = data;
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}
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return i;
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}
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static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
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u8 length, u8 *values)
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{
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u8 oldvalues[255];
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s32 ret;
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int tries = 0;
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dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
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ret = ds1307_read_block_data_once(client, command, length, values);
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if (ret < 0)
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return ret;
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do {
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if (++tries > BLOCK_DATA_MAX_TRIES) {
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dev_err(&client->dev,
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"ds1307_read_block_data failed\n");
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return -EIO;
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}
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memcpy(oldvalues, values, length);
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ret = ds1307_read_block_data_once(client, command, length,
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values);
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if (ret < 0)
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return ret;
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} while (memcmp(oldvalues, values, length));
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return length;
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}
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static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
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u8 length, const u8 *values)
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{
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u8 currvalues[255];
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int tries = 0;
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dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
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do {
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s32 i, ret;
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if (++tries > BLOCK_DATA_MAX_TRIES) {
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dev_err(&client->dev,
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"ds1307_write_block_data failed\n");
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return -EIO;
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}
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for (i = 0; i < length; i++) {
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ret = i2c_smbus_write_byte_data(client, command + i,
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values[i]);
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if (ret < 0)
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return ret;
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}
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ret = ds1307_read_block_data_once(client, command, length,
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currvalues);
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if (ret < 0)
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return ret;
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} while (memcmp(currvalues, values, length));
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return length;
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}
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static inline struct ds1307 *to_ds1307_priv(struct rtc_device *rtcdev)
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{
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return container_of(rtcdev, struct ds1307, rtc);
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}
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static int ds1307_get_time(struct rtc_device *rtcdev, struct rtc_time *t)
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{
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struct device_d *dev = rtcdev->dev;
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struct ds1307 *ds1307 = to_ds1307_priv(rtcdev);
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int tmp;
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/* read the RTC date and time registers all at once */
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tmp = ds1307->read_block_data(ds1307->client,
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ds1307->offset, 7, ds1307->regs);
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if (tmp != 7) {
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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: %7ph\n", "read", ds1307->regs);
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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 rtc_device *rtcdev, struct rtc_time *t)
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{
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struct device_d *dev = rtcdev->dev;
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struct ds1307 *ds1307 = to_ds1307_priv(rtcdev);
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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[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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dev_dbg(dev, "%s: %7ph\n", "write", buf);
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result = ds1307->write_block_data(ds1307->client,
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ds1307->offset, 7, buf);
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if (result < 0) {
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dev_err(dev, "%s error %d\n", "write", result);
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return result;
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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 int ds1307_probe(struct device_d *dev)
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{
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struct i2c_client *client = to_i2c_client(dev);
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struct ds1307 *ds1307;
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int err = -ENODEV;
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int tmp;
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unsigned char *buf;
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unsigned long driver_data;
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ds1307 = xzalloc(sizeof(struct ds1307));
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err = dev_get_drvdata(dev, &driver_data);
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if (err)
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goto exit;
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ds1307->client = client;
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ds1307->type = driver_data;
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buf = ds1307->regs;
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ds1307->read_block_data = ds1307_read_block_data;
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ds1307->write_block_data = ds1307_write_block_data;
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read_rtc:
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/* read RTC registers */
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tmp = ds1307->read_block_data(client, ds1307->offset, 8, buf);
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if (tmp != 8) {
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dev_dbg(&client->dev, "read error %d\n", tmp);
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err = -EIO;
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goto exit;
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}
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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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/* 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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default:
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break;
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}
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tmp = ds1307->regs[DS1307_REG_HOUR];
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switch (ds1307->type) {
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default:
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if (!(tmp & DS1307_BIT_12HR))
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break;
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/*
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* Be sure we're in 24 hour mode. Multi-master systems
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* take note...
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*/
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tmp = bcd2bin(tmp & 0x1f);
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if (tmp == 12)
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tmp = 0;
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if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
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tmp += 12;
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i2c_smbus_write_byte_data(client,
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ds1307->offset + DS1307_REG_HOUR,
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bin2bcd(tmp));
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}
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ds1307->rtc.ops = &ds13xx_rtc_ops;
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ds1307->rtc.dev = dev;
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err = rtc_register(&ds1307->rtc);
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exit:
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return err;
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}
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static struct driver_d ds1307_driver = {
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.name = "rtc-ds1307",
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.probe = ds1307_probe,
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.id_table = ds1307_id,
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};
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static int __init ds1307_init(void)
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{
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return i2c_driver_register(&ds1307_driver);
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}
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device_initcall(ds1307_init);
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