AM335x WakeUp&Sleep

static int am33xx_pm_suspend(void)
{
	int state, ret = 0;

	struct omap_hwmod *gpmc_oh, *usb_oh, *gpio1_oh, *rtc_oh;

	usb_oh		= omap_hwmod_lookup("usb_otg_hs");
	gpmc_oh		= omap_hwmod_lookup("gpmc");
	gpio1_oh	= omap_hwmod_lookup("gpio1");	/* WKUP domain GPIO */
	rtc_oh		= omap_hwmod_lookup("rtc");

	omap_hwmod_enable(usb_oh);
	omap_hwmod_enable(gpmc_oh);
	
	/*
	 * Keep USB module enabled during standby
	 * to enable USB remote wakeup
	 * Note: This will result in hard-coding USB state
	 * during standby
	 */

	if (suspend_state != PM_SUSPEND_STANDBY)
	   omap_hwmod_idle(usb_oh);

	omap_hwmod_idle(gpmc_oh);

	/*
	 * Keep RTC module enabled during standby
	 * for PG2.x to enable wakeup from RTC.
	 */
	if ((omap_rev() >= AM335X_REV_ES2_0) &&
		(suspend_state == PM_SUSPEND_STANDBY)){
		omap_hwmod_enable(rtc_oh);
	}

	/*
	 * Disable the GPIO module. This ensure that
	 * only sWAKEUP interrupts to Cortex-M3 get generated
	 *
	 * XXX: EVM_SK uses a GPIO0 pin for VTP control
	 * in suspend and hence we can't do this for EVM_SK
	 * alone. The side-effect of this is that GPIO wakeup
	 * might have issues. Refer to commit 672639b for the
	 * details
	 */
	/*
	 * Keep GPIO0 module enabled during standby to
	 * support wakeup via GPIO0 keys.
	 */
	if ((suspend_cfg_param_list[EVM_ID] != EVM_SK) && (suspend_state != PM_SUSPEND_STANDBY)){
		omap_hwmod_idle(gpio1_oh);
	}

	/*
	 * Update Suspend_State value to be used in sleep33xx.S to keep
	 * GPIO0 module enabled during standby for EVM-SK
	 */
	if (suspend_state == PM_SUSPEND_STANDBY)
		suspend_cfg_param_list[SUSPEND_STATE] = PM_STANDBY;
	else
		suspend_cfg_param_list[SUSPEND_STATE] = PM_DS0;

#if 0  /*by szf*/
	/*
	 * Keep Touchscreen module enabled during standby
	 * to enable wakeup from standby.
	 */

	if (suspend_state == PM_SUSPEND_STANDBY)
		writel(0x2, AM33XX_CM_WKUP_ADC_TSC_CLKCTRL);
#endif

	if (gfx_l3_clkdm && gfx_l4ls_clkdm) {
		clkdm_sleep(gfx_l3_clkdm);
		clkdm_sleep(gfx_l4ls_clkdm);
	}

	/* Try to put GFX to sleep */
	if (gfx_pwrdm)
		pwrdm_set_next_pwrst(gfx_pwrdm, PWRDM_POWER_OFF);
	else
		pr_err("Could not program GFX to low power state\n");

	omap3_intc_suspend();

	am33xx_standby_setup(suspend_state);

	writel(0x0, AM33XX_CM_MPU_MPU_CLKCTRL);

	ret = cpu_suspend(0, am33xx_do_sram_idle);

	writel(0x2, AM33XX_CM_MPU_MPU_CLKCTRL);

	if (gfx_pwrdm) {
		state = pwrdm_read_pwrst(gfx_pwrdm);
		if (state != PWRDM_POWER_OFF)
			pr_err("GFX domain did not transition to low power state\n");
		else
			pr_info("GFX domain entered low power state\n");
	}

	/* XXX: Why do we need to wakeup the clockdomains? */
	if(gfx_l3_clkdm && gfx_l4ls_clkdm) {
		clkdm_wakeup(gfx_l3_clkdm);
		clkdm_wakeup(gfx_l4ls_clkdm);
	}

	/*
	 * Touchscreen module was enabled during standby
	 * Disable it here.
	 */
	if (suspend_state == PM_SUSPEND_STANDBY)
		writel(0x0, AM33XX_CM_WKUP_ADC_TSC_CLKCTRL);

	/*
	 * Put USB module to idle on resume from standby
	 */

	if (suspend_state == PM_SUSPEND_STANDBY)
		omap_hwmod_idle(usb_oh);

	/*
	 * Put RTC module to idle on resume from standby
	 * for PG2.x.
	 */
	if ((omap_rev() >= AM335X_REV_ES2_0) && (suspend_state == PM_SUSPEND_STANDBY))
		omap_hwmod_idle(rtc_oh);

	ret = am33xx_verify_lp_state(ret);

	/*
	 * Enable the GPIO module. Once the driver is
	 * fully adapted to runtime PM this will go away
	 */
	/*suspend_enter
	 * During standby, GPIO was not disabled. Hence no
	 * need to enable it here.
	 */
	if ((suspend_cfg_param_list[EVM_ID] != EVM_SK) &&
			(suspend_state != PM_SUSPEND_STANDBY))
		omap_hwmod_enable(gpio1_oh);

	return ret;
}