On 27.07.2018 11:15, Robin Gong wrote:

quoted

-----Original Message-----
From: Oleksij Rempel [mailto:o.rempel@pengutronix.de]
Sent: 2018年7月26日 17:22
To: Shawn Guo <shawnguo@kernel.org>; Mark Brown <broonie@kernel.org>;
Rafael J. Wysocki [off-list ref]
Cc: Oleksij Rempel <o.rempel@pengutronix.de>; kernel@pengutronix.de;
devicetree@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
linux-clk@vger.kernel.org; linux-kernel@vger.kernel.org; Andrew Morton
[off-list ref]; Liam Girdwood [off-list ref];
Leonard Crestez [off-list ref]; Rob Herring
[off-list ref]; Mark Rutland [off-list ref]; Michael
Turquette [off-list ref]; Stephen Boyd
[off-list ref]; Fabio Estevam [off-list ref]; Russell
King [off-list ref]; dl-linux-imx [off-list ref]; Robin Gong
[off-list ref]; A.s. Dong [off-list ref]
Subject: [PATCH v8 2/6] 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:
https://emea01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.
nxp.com%2Fassets%2Fdocuments%2Fdata%2Fen%2Freference-manuals%2FIM
X6DQRM.pdf&amp;data=02%7C01%7Cyibin.gong%40nxp.com%7C193fd19e3a
40416ffa4a08d5f2d9583c%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C1
%7C636681937661914076&amp;sdata=lICAelYpUh4%2Ft%2Fs7N9mdk2cLQMi
cHcOqQ07vTOUoyNY%3D&amp;reserved=0
page 5083

This patch implements step 4. of this sequence.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 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 017539dd712b..2f5c643f62fb 100644
--- a/arch/arm/mach-imx/pm-imx6.c
+++ b/arch/arm/mach-imx/pm-imx6.c

@@ -601,6 +601,28 @@ 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);

'syscon-poweroff' and 'pmic-stby-poweroff ' should be chosen as a single
Poweroff way for any i.mx6 board. Why not delete directly 'syscon-poweroff' in dts 
to avoid such two power off ways coexist?

pm_power_off can be registred by any part of the kernel. So, we need it
to avoid conflicts or at least to be able see them.

On other hand, you are right. syscon-poweroff should be disabled for
this board.

quoted

+		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;

@@ -617,6 +639,9 @@ 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)
--
2.18.0