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pm.c

/*
 * Alchemy Development Board example suspend userspace interface.
 *
 * (c) 2008 Manuel Lauss <mano@roarinelk.homelinux.net>
 */

#include <linux/init.h>
#include <linux/kobject.h>
#include <linux/suspend.h>
#include <linux/sysfs.h>
#include <asm/mach-au1x00/au1000.h>
#include <asm/mach-au1x00/gpio.h>

/*
 * Generic suspend userspace interface for Alchemy development boards.
 * This code exports a few sysfs nodes under /sys/power/db1x/ which
 * can be used by userspace to en/disable all au1x-provided wakeup
 * sources and configure the timeout after which the the TOYMATCH2 irq
 * is to trigger a wakeup.
 */


static unsigned long db1x_pm_sleep_secs;
static unsigned long db1x_pm_wakemsk;
static unsigned long db1x_pm_last_wakesrc;

static int db1x_pm_enter(suspend_state_t state)
{
      /* enable GPIO based wakeup */
      alchemy_gpio1_input_enable();

      /* clear and setup wake cause and source */
      au_writel(0, SYS_WAKEMSK);
      au_sync();
      au_writel(0, SYS_WAKESRC);
      au_sync();

      au_writel(db1x_pm_wakemsk, SYS_WAKEMSK);
      au_sync();

      /* setup 1Hz-timer-based wakeup: wait for reg access */
      while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_M20)
            asm volatile ("nop");

      au_writel(au_readl(SYS_TOYREAD) + db1x_pm_sleep_secs, SYS_TOYMATCH2);
      au_sync();

      /* wait for value to really hit the register */
      while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_M20)
            asm volatile ("nop");

      /* ...and now the sandman can come! */
      au_sleep();

      return 0;
}

static int db1x_pm_begin(suspend_state_t state)
{
      if (!db1x_pm_wakemsk) {
            printk(KERN_ERR "db1x: no wakeup source activated!\n");
            return -EINVAL;
      }

      return 0;
}

static void db1x_pm_end(void)
{
      /* read and store wakeup source, the clear the register. To
       * be able to clear it, WAKEMSK must be cleared first.
       */
      db1x_pm_last_wakesrc = au_readl(SYS_WAKESRC);

      au_writel(0, SYS_WAKEMSK);
      au_writel(0, SYS_WAKESRC);
      au_sync();

}

static struct platform_suspend_ops db1x_pm_ops = {
      .valid            = suspend_valid_only_mem,
      .begin            = db1x_pm_begin,
      .enter            = db1x_pm_enter,
      .end        = db1x_pm_end,
};

#define ATTRCMP(x) (0 == strcmp(attr->attr.name, #x))

static ssize_t db1x_pmattr_show(struct kobject *kobj,
                        struct kobj_attribute *attr,
                        char *buf)
{
      int idx;

      if (ATTRCMP(timer_timeout))
            return sprintf(buf, "%lu\n", db1x_pm_sleep_secs);

      else if (ATTRCMP(timer))
            return sprintf(buf, "%u\n",
                        !!(db1x_pm_wakemsk & SYS_WAKEMSK_M2));

      else if (ATTRCMP(wakesrc))
            return sprintf(buf, "%lu\n", db1x_pm_last_wakesrc);

      else if (ATTRCMP(gpio0) || ATTRCMP(gpio1) || ATTRCMP(gpio2) ||
             ATTRCMP(gpio3) || ATTRCMP(gpio4) || ATTRCMP(gpio5) ||
             ATTRCMP(gpio6) || ATTRCMP(gpio7)) {
            idx = (attr->attr.name)[4] - '0';
            return sprintf(buf, "%d\n",
                  !!(db1x_pm_wakemsk & SYS_WAKEMSK_GPIO(idx)));

      } else if (ATTRCMP(wakemsk)) {
            return sprintf(buf, "%08lx\n", db1x_pm_wakemsk);
      }

      return -ENOENT;
}

static ssize_t db1x_pmattr_store(struct kobject *kobj,
                         struct kobj_attribute *attr,
                         const char *instr,
                         size_t bytes)
{
      unsigned long l;
      int tmp;

      if (ATTRCMP(timer_timeout)) {
            tmp = strict_strtoul(instr, 0, &l);
            if (tmp)
                  return tmp;

            db1x_pm_sleep_secs = l;

      } else if (ATTRCMP(timer)) {
            if (instr[0] != '0')
                  db1x_pm_wakemsk |= SYS_WAKEMSK_M2;
            else
                  db1x_pm_wakemsk &= ~SYS_WAKEMSK_M2;

      } else if (ATTRCMP(gpio0) || ATTRCMP(gpio1) || ATTRCMP(gpio2) ||
               ATTRCMP(gpio3) || ATTRCMP(gpio4) || ATTRCMP(gpio5) ||
               ATTRCMP(gpio6) || ATTRCMP(gpio7)) {
            tmp = (attr->attr.name)[4] - '0';
            if (instr[0] != '0') {
                  db1x_pm_wakemsk |= SYS_WAKEMSK_GPIO(tmp);
            } else {
                  db1x_pm_wakemsk &= ~SYS_WAKEMSK_GPIO(tmp);
            }

      } else if (ATTRCMP(wakemsk)) {
            tmp = strict_strtoul(instr, 0, &l);
            if (tmp)
                  return tmp;

            db1x_pm_wakemsk = l & 0x0000003f;

      } else
            bytes = -ENOENT;

      return bytes;
}

#define ATTR(x)                                       \
      static struct kobj_attribute x##_attribute =          \
            __ATTR(x, 0664, db1x_pmattr_show,         \
                        db1x_pmattr_store);

ATTR(gpio0)       /* GPIO-based wakeup enable */
ATTR(gpio1)
ATTR(gpio2)
ATTR(gpio3)
ATTR(gpio4)
ATTR(gpio5)
ATTR(gpio6)
ATTR(gpio7)
ATTR(timer)       /* TOYMATCH2-based wakeup enable */
ATTR(timer_timeout)     /* timer-based wakeup timeout value, in seconds */
ATTR(wakesrc)           /* contents of SYS_WAKESRC after last wakeup */
ATTR(wakemsk)           /* direct access to SYS_WAKEMSK */

#define ATTR_LIST(x)    & x ## _attribute.attr
static struct attribute *db1x_pmattrs[] = {
      ATTR_LIST(gpio0),
      ATTR_LIST(gpio1),
      ATTR_LIST(gpio2),
      ATTR_LIST(gpio3),
      ATTR_LIST(gpio4),
      ATTR_LIST(gpio5),
      ATTR_LIST(gpio6),
      ATTR_LIST(gpio7),
      ATTR_LIST(timer),
      ATTR_LIST(timer_timeout),
      ATTR_LIST(wakesrc),
      ATTR_LIST(wakemsk),
      NULL,       /* terminator */
};

static struct attribute_group db1x_pmattr_group = {
      .name = "db1x",
      .attrs      = db1x_pmattrs,
};

/*
 * Initialize suspend interface
 */
static int __init pm_init(void)
{
      /* init TOY to tick at 1Hz if not already done. No need to wait
       * for confirmation since there's plenty of time from here to
       * the next suspend cycle.
       */
      if (au_readl(SYS_TOYTRIM) != 32767) {
            au_writel(32767, SYS_TOYTRIM);
            au_sync();
      }

      db1x_pm_last_wakesrc = au_readl(SYS_WAKESRC);

      au_writel(0, SYS_WAKESRC);
      au_sync();
      au_writel(0, SYS_WAKEMSK);
      au_sync();

      suspend_set_ops(&db1x_pm_ops);

      return sysfs_create_group(power_kobj, &db1x_pmattr_group);
}

late_initcall(pm_init);

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