linux-imx

/*

 * Copyright (C) 2007-2009 ST-Ericsson AB

 * License terms: GNU General Public License (GPL) version 2

 * RTC clock driver for the AB3100 Analog Baseband Chip

 * Author: Linus Walleij <linus.walleij@stericsson.com>

 */

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/init.h>

#include <linux/platform_device.h>

#include <linux/rtc.h>

#include <linux/mfd/abx500.h>

​

/* Clock rate in Hz */

#define AB3100_RTC_CLOCK_RATE   32768

​

/*

 * The AB3100 RTC registers. These are the same for

 * AB3000 and AB3100.

 * Control register:

 * Bit 0: RTC Monitor cleared=0, active=1, if you set it

 *        to 1 it remains active until RTC power is lost.

 * Bit 1: 32 kHz Oscillator, 0 = on, 1 = bypass

 * Bit 2: Alarm on, 0 = off, 1 = on

 * Bit 3: 32 kHz buffer disabling, 0 = enabled, 1 = disabled

 */

#define AB3100_RTC      0x53

/* default setting, buffer disabled, alarm on */

#define RTC_SETTING     0x30

/* Alarm when AL0-AL3 == TI0-TI3  */

#define AB3100_AL0      0x56

#define AB3100_AL1      0x57

#define AB3100_AL2      0x58

#define AB3100_AL3      0x59

/* This 48-bit register that counts up at 32768 Hz */

#define AB3100_TI0      0x5a

#define AB3100_TI1      0x5b

#define AB3100_TI2      0x5c

#define AB3100_TI3      0x5d

#define AB3100_TI4      0x5e

#define AB3100_TI5      0x5f

​

/*

 * RTC clock functions and device struct declaration

 */

static int ab3100_rtc_set_mmss(struct device *dev, time64_t secs)

{

    u8 regs[] = {AB3100_TI0, AB3100_TI1, AB3100_TI2,

             AB3100_TI3, AB3100_TI4, AB3100_TI5};

    unsigned char buf[6];

    u64 hw_counter = secs * AB3100_RTC_CLOCK_RATE * 2;

    int err = 0;

    int i;

​

    buf[0] = (hw_counter) & 0xFF;

    buf[1] = (hw_counter >> 8) & 0xFF;

    buf[2] = (hw_counter >> 16) & 0xFF;

    buf[3] = (hw_counter >> 24) & 0xFF;

    buf[4] = (hw_counter >> 32) & 0xFF;

    buf[5] = (hw_counter >> 40) & 0xFF;

​

    for (i = 0; i < 6; i++) {

        err = abx500_set_register_interruptible(dev, 0,