linux-imx

/*

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

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

 * Real Time Clock interface for ST-Ericsson AB COH 901 331 RTC.

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

 * Based on rtc-pl031.c by Deepak Saxena <dsaxena@plexity.net>

 * Copyright 2006 (c) MontaVista Software, Inc.

 */

#include <linux/init.h>

#include <linux/module.h>

#include <linux/mod_devicetable.h>

#include <linux/rtc.h>

#include <linux/clk.h>

#include <linux/interrupt.h>

#include <linux/pm.h>

#include <linux/platform_device.h>

#include <linux/io.h>

#include <linux/slab.h>

​

/*

 * Registers in the COH 901 331

 */

/* Alarm value 32bit (R/W) */

#define COH901331_ALARM     0x00U

/* Used to set current time 32bit (R/W) */

#define COH901331_SET_TIME  0x04U

/* Indication if current time is valid 32bit (R/-) */

#define COH901331_VALID     0x08U

/* Read the current time 32bit (R/-) */

#define COH901331_CUR_TIME  0x0cU

/* Event register for the "alarm" interrupt */

#define COH901331_IRQ_EVENT 0x10U

/* Mask register for the "alarm" interrupt */

#define COH901331_IRQ_MASK  0x14U

/* Force register for the "alarm" interrupt */

#define COH901331_IRQ_FORCE 0x18U

​

/*

 * Reference to RTC block clock

 * Notice that the frequent clk_enable()/clk_disable() on this

 * clock is mainly to be able to turn on/off other clocks in the

 * hierarchy as needed, the RTC clock is always on anyway.

 */

struct coh901331_port {

    struct rtc_device *rtc;

    struct clk *clk;

    void __iomem *virtbase;

    int irq;

#ifdef CONFIG_PM_SLEEP

    u32 irqmaskstore;

#endif

};

​

static irqreturn_t coh901331_interrupt(int irq, void *data)

{

    struct coh901331_port *rtap = data;

​

    clk_enable(rtap->clk);

    /* Ack IRQ */

    writel(1, rtap->virtbase + COH901331_IRQ_EVENT);

    /*

     * Disable the interrupt. This is necessary because

     * the RTC lives on a lower-clocked line and will

     * not release the IRQ line until after a few (slower)

     * clock cycles. The interrupt will be re-enabled when

     * a new alarm is set anyway.

     */

    writel(0, rtap->virtbase + COH901331_IRQ_MASK);

    clk_disable(rtap->clk);

​

    /* Set alarm flag */

    rtc_update_irq(rtap->rtc, 1, RTC_AF);

​

    return IRQ_HANDLED;

}

​

static int coh901331_read_time(struct device *dev, struct rtc_time *tm)

{

    struct coh901331_port *rtap = dev_get_drvdata(dev);

​

    clk_enable(rtap->clk);

    /* Check if the time is valid */

    if (readl(rtap->virtbase + COH901331_VALID)) {

        rtc_time_to_tm(readl(rtap->virtbase + COH901331_CUR_TIME), tm);

        clk_disable(rtap->clk);

        return 0;

    }

    clk_disable(rtap->clk);

    return -EINVAL;

}

​

static int coh901331_set_mmss(struct device *dev, unsigned long secs)