msp_hwbutton.c

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/*
 * Sets up interrupt handlers for various hardware switches which are
 * connected to interrupt lines.
 *
 * Copyright 2005-2207 PMC-Sierra, Inc.
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
 *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
 *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
 *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *  You should have received a copy of the  GNU General Public License along
 *  with this program; if not, write  to the Free Software Foundation, Inc.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>

#include <msp_int.h>
#include <msp_regs.h>
#include <msp_regops.h>

/* For hwbutton_interrupt->initial_state */
#define HWBUTTON_HI 0x1
#define HWBUTTON_LO 0x2

/*
 * This struct describes a hardware button
 */
struct hwbutton_interrupt {
    char *name;         /* Name of button */
    int irq;            /* Actual LINUX IRQ */
    int eirq;           /* Extended IRQ number (0-7) */
    int initial_state;      /* The "normal" state of the switch */
    void (*handle_hi)(void *);  /* Handler: switch input has gone HI */
    void (*handle_lo)(void *);  /* Handler: switch input has gone LO */
    void *data;         /* Optional data to pass to handler */
};

#ifdef CONFIG_PMC_MSP7120_GW
extern void msp_restart(char *);

static void softreset_push(void *data)
{
    printk(KERN_WARNING "SOFTRESET switch was pushed\n");

    /*
     * In the future you could move this to the release handler,
     * timing the difference between the 'push' and 'release', and only
     * doing this ungraceful restart if the button has been down for
     * a certain amount of time; otherwise doing a graceful restart.
     */

    msp_restart(NULL);
}

static void softreset_release(void *data)
{
    printk(KERN_WARNING "SOFTRESET switch was released\n");

    /* Do nothing */
}

static void standby_on(void *data)
{
    printk(KERN_WARNING "STANDBY switch was set to ON (not implemented)\n");

    /* TODO: Put board in standby mode */
}

static void standby_off(void *data)
{
    printk(KERN_WARNING
        "STANDBY switch was set to OFF (not implemented)\n");

    /* TODO: Take out of standby mode */
}

static struct hwbutton_interrupt softreset_sw = {
    .name = "Softreset button",
    .irq = MSP_INT_EXT0,
    .eirq = 0,
    .initial_state = HWBUTTON_HI,
    .handle_hi = softreset_release,
    .handle_lo = softreset_push,
    .data = NULL,
};

static struct hwbutton_interrupt standby_sw = {
    .name = "Standby switch",
    .irq = MSP_INT_EXT1,
    .eirq = 1,
    .initial_state = HWBUTTON_HI,
    .handle_hi = standby_off,
    .handle_lo = standby_on,
    .data = NULL,
};
#endif /* CONFIG_PMC_MSP7120_GW */

static irqreturn_t hwbutton_handler(int irq, void *data)
{
    struct hwbutton_interrupt *hirq = data;
    unsigned long cic_ext = *CIC_EXT_CFG_REG;

    if (CIC_EXT_IS_ACTIVE_HI(cic_ext, hirq->eirq)) {
        /* Interrupt: pin is now HI */
        CIC_EXT_SET_ACTIVE_LO(cic_ext, hirq->eirq);
        hirq->handle_hi(hirq->data);
    } else {
        /* Interrupt: pin is now LO */
        CIC_EXT_SET_ACTIVE_HI(cic_ext, hirq->eirq);
        hirq->handle_lo(hirq->data);
    }

    /*
     * Invert the POLARITY of this level interrupt to ack the interrupt
     * Thus next state change will invoke the opposite message
     */
    *CIC_EXT_CFG_REG = cic_ext;

    return IRQ_HANDLED;
}

static int msp_hwbutton_register(struct hwbutton_interrupt *hirq)
{
    unsigned long cic_ext;

    if (hirq->handle_hi == NULL || hirq->handle_lo == NULL)
        return -EINVAL;

    cic_ext = *CIC_EXT_CFG_REG;
    CIC_EXT_SET_TRIGGER_LEVEL(cic_ext, hirq->eirq);
    if (hirq->initial_state == HWBUTTON_HI)
        CIC_EXT_SET_ACTIVE_LO(cic_ext, hirq->eirq);
    else
        CIC_EXT_SET_ACTIVE_HI(cic_ext, hirq->eirq);
    *CIC_EXT_CFG_REG = cic_ext;

    return request_irq(hirq->irq, hwbutton_handler, 0,
               hirq->name, hirq);
}

static int __init msp_hwbutton_setup(void)
{
#ifdef CONFIG_PMC_MSP7120_GW
    msp_hwbutton_register(&softreset_sw);
    msp_hwbutton_register(&standby_sw);
#endif
    return 0;
}

subsys_initcall(msp_hwbutton_setup);