power: reset: sc27xx: Power off the external subsystems' connection

sherryzong · sre · commit 6cdd5b09cbe6 · 2020-03-11T23:32:09.000+01:00
When powering off the whole system, we should power off some external
subsystems' connection firstly, otherwise some external subsystems
will hold some power and result in powering down abnormally.

Signed-off-by: Sherry Zong &lt;sherry.zong@unisoc.com&gt;
Signed-off-by: Baolin Wang &lt;baolin.wang7@gmail.com&gt;
Signed-off-by: Sebastian Reichel &lt;sebastian.reichel@collabora.com&gt;
diff --git a/drivers/power/reset/sc27xx-poweroff.c b/drivers/power/reset/sc27xx-poweroff.c
@@ -13,6 +13,8 @@
 
 #define SC27XX_PWR_PD_HW	0xc2c
 #define SC27XX_PWR_OFF_EN	BIT(0)
+#define SC27XX_SLP_CTRL		0xdf0
+#define SC27XX_LDO_XTL_EN	BIT(3)
 
 static struct regmap *regmap;
 
@@ -40,6 +42,9 @@ static struct syscore_ops poweroff_syscore_ops = {
 
 static void sc27xx_poweroff_do_poweroff(void)
 {
+	/* Disable the external subsys connection's power firstly */
+	regmap_write(regmap, SC27XX_SLP_CTRL, SC27XX_LDO_XTL_EN);
+
 	regmap_write(regmap, SC27XX_PWR_PD_HW, SC27XX_PWR_OFF_EN);
 }
 

Original file line number	Diff line number	Diff line change
`@@ -13,6 +13,8 @@`
`13`	`13`
`14`	`14`	`#define SC27XX_PWR_PD_HW 0xc2c`
`15`	`15`	`#define SC27XX_PWR_OFF_EN BIT(0)`
	`16`	`+#define SC27XX_SLP_CTRL 0xdf0`
	`17`	`+#define SC27XX_LDO_XTL_EN BIT(3)`
`16`	`18`
`17`	`19`	`static struct regmap *regmap;`
`18`	`20`
`@@ -40,6 +42,9 @@ static struct syscore_ops poweroff_syscore_ops = {`
`40`	`42`
`41`	`43`	`static void sc27xx_poweroff_do_poweroff(void)`
`42`	`44`	`{`
	`45`	`+ /* Disable the external subsys connection's power firstly */`
	`46`	`+ regmap_write(regmap, SC27XX_SLP_CTRL, SC27XX_LDO_XTL_EN);`
	`47`	`+`
`43`	`48`	`regmap_write(regmap, SC27XX_PWR_PD_HW, SC27XX_PWR_OFF_EN);`
`44`	`49`	`}`
`45`	`50`