linux-imx

/*

 * rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.

 *

 *  Copyright (C) 2005 James Chapman (ds1337 core)

 *  Copyright (C) 2006 David Brownell

 *  Copyright (C) 2009 Matthias Fuchs (rx8025 support)

 *  Copyright (C) 2012 Bertrand Achard (nvram access fixes)

 *

 * 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/acpi.h>

#include <linux/bcd.h>

#include <linux/i2c.h>

#include <linux/init.h>

#include <linux/module.h>

#include <linux/of_device.h>

#include <linux/rtc/ds1307.h>

#include <linux/rtc.h>

#include <linux/slab.h>

#include <linux/string.h>

#include <linux/hwmon.h>

#include <linux/hwmon-sysfs.h>

#include <linux/clk-provider.h>

#include <linux/regmap.h>

​

/*

 * We can't determine type by probing, but if we expect pre-Linux code

 * to have set the chip up as a clock (turning on the oscillator and

 * setting the date and time), Linux can ignore the non-clock features.

 * That's a natural job for a factory or repair bench.

 */

enum ds_type {

    ds_1307,

    ds_1308,

    ds_1337,

    ds_1338,

    ds_1339,

    ds_1340,

    ds_1341,

    ds_1388,

    ds_3231,

    m41t0,

    m41t00,

    m41t11,

    mcp794xx,

    rx_8025,

    rx_8130,

    last_ds_type /* always last */

    /* rs5c372 too?  different address... */

};

​

/* RTC registers don't differ much, except for the century flag */

#define DS1307_REG_SECS     0x00    /* 00-59 */

#   define DS1307_BIT_CH        0x80

#   define DS1340_BIT_nEOSC     0x80

#   define MCP794XX_BIT_ST      0x80

#define DS1307_REG_MIN      0x01    /* 00-59 */

#   define M41T0_BIT_OF     0x80

#define DS1307_REG_HOUR     0x02    /* 00-23, or 1-12{am,pm} */

#   define DS1307_BIT_12HR      0x40    /* in REG_HOUR */