From 496afe51ba67a2ee8b194612e498ec5ae2a16e4c Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Thu, 2 Aug 2018 12:34:21 +0200
Subject: ARM: imx6: register pm_power_off handler if "fsl,pmic-stby-poweroff"
 is set

From: Oleksij Rempel <o.rempel@pengutronix.de>

[ Upstream commit 8148d2136002da2e2887caf6a07bbd9c033f14f3 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arm/mach-imx/pm-imx6.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/arch/arm/mach-imx/pm-imx6.c b/arch/arm/mach-imx/pm-imx6.c
index b08e407d8d96f..529f4b5bbd3a7 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)
-- 
2.20.1