ARM: imx6: register pm_power_off handler if "fsl,pmic-stby-poweroff" is set

One of the Freescale recommended sequences for power off with external
PMIC is the following:
...
3.  SoC is programming PMIC for power off when standby is asserted.
4.  In CCM STOP mode, Standby is asserted, PMIC gates SoC supplies.

See:
http://www.nxp.com/assets/documents/data/en/reference-manuals/IMX6DQRM.pdf
page 5083

This patch implements step 4. of this sequence.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/arch/arm/mach-imx/pm-imx6.c b/arch/arm/mach-imx/pm-imx6.c
index b08e407d8d96..529f4b5bbd3a 100644
--- a/arch/arm/mach-imx/pm-imx6.c
+++ b/arch/arm/mach-imx/pm-imx6.c
@@ -618,6 +618,28 @@ static void __init imx6_pm_common_init(const struct imx6_pm_socdata
                                    IMX6Q_GPR1_GINT);
 }
 
+static void imx6_pm_stby_poweroff(void)
+{
+        imx6_set_lpm(STOP_POWER_OFF);
+        imx6q_suspend_finish(0);
+
+        mdelay(1000);
+
+        pr_emerg("Unable to poweroff system\n");
+}
+
+static int imx6_pm_stby_poweroff_probe(void)
+{
+        if (pm_power_off) {
+                pr_warn("%s: pm_power_off already claimed  %p %pf!\n",
+                        __func__, pm_power_off, pm_power_off);
+                return -EBUSY;
+        }
+
+        pm_power_off = imx6_pm_stby_poweroff;
+        return 0;
+}
+
 void __init imx6_pm_ccm_init(const char *ccm_compat)
 {
         struct device_node *np;
@@ -634,6 +656,9 @@ void __init imx6_pm_ccm_init(const char *ccm_compat)
         val = readl_relaxed(ccm_base + CLPCR);
         val &= ~BM_CLPCR_LPM;
         writel_relaxed(val, ccm_base + CLPCR);
+
+        if (of_property_read_bool(np, "fsl,pmic-stby-poweroff"))
+                imx6_pm_stby_poweroff_probe();
 }
 
 void __init imx6q_pm_init(void)