Some optimization for SC27XX poweroff driver

This patch set fixes external subsystems' power issue and allows the SC27XX poweroff driver building into a module.

Baolin Wang (2):
power: reset: sc27xx: Change to use cpu_down()
power: reset: sc27xx: Allow the SC27XX poweroff driver building into a
module

Sherry Zong (1):
power: reset: sc27xx: Power off the external subsystems' connection

 drivers/power/reset/Kconfig           |  2 +-
 drivers/power/reset/sc27xx-poweroff.c | 21 +++++++++++++++++----
 2 files changed, 18 insertions(+), 5 deletions(-)

1.9.1

From: Sherry Zong <[email protected]>

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.

---
 drivers/power/reset/sc27xx-poweroff.c | 5 +++++
 1 file changed, 5 insertions(+)

index 29fb08b..2bedd4c 100644
@@ -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 void sc27xx_poweroff_shutdown(void)
 
 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);
 }
 

1.9.1

To allow the SC27XX driver can be built as a module, and the freeze_secondary_cpus() symbol is not exported, thus we can change to use the exported cpu_down() API to shut down other cpus to avoid racing, which is same as the freeze_secondary_cpus().

---
 drivers/power/reset/sc27xx-poweroff.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

index 2bedd4c..91b5ece 100644
@@ -29,10 +29,13 @@
  */
 static void sc27xx_poweroff_shutdown(void)
 {
-#ifdef CONFIG_PM_SLEEP_SMP
-	int cpu = smp_processor_id();
+#ifdef CONFIG_HOTPLUG_CPU
+	int cpu;
 
-	freeze_secondary_cpus(cpu);
+	for_each_online_cpu(cpu) {
+		if (cpu != smp_processor_id())
+			cpu_down(cpu);
+	}
 #endif
 }
 

1.9.1

Change the config to 'tristate' and use module_platform_driver() to allow the SC27XX poweroff driver building into a module, as well as adding some mudule information.

---
 drivers/power/reset/Kconfig           | 2 +-
 drivers/power/reset/sc27xx-poweroff.c | 7 ++++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

index 513efe8..8903803 100644
@@ -248,7 +248,7 @@ config SYSCON_REBOOT_MODE
 	  action according to the mode.
 
 config POWER_RESET_SC27XX
-	bool "Spreadtrum SC27xx PMIC power-off driver"
+	tristate "Spreadtrum SC27xx PMIC power-off driver"
 	depends on MFD_SC27XX_PMIC || COMPILE_TEST
 	help
 	  This driver supports powering off a system through

index 91b5ece..6986307 100644
@@ -6,6 +6,7 @@
 
 #include <linux/cpu.h>
 #include <linux/kernel.h>
+#include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/pm.h>
 #include <linux/regmap.h>

@@ -71,4 +72,8 @@ static int sc27xx_poweroff_probe(struct platform_device *pdev)
 		.name = "sc27xx-poweroff",
 	},
 };
-builtin_platform_driver(sc27xx_poweroff_driver);
+module_platform_driver(sc27xx_poweroff_driver);
+
+MODULE_DESCRIPTION("Power off driver for SC27XX PMIC Device");
+MODULE_AUTHOR("Baolin Wang <[email protected]>");
+MODULE_LICENSE("GPL v2");

1.9.1

Hi,

Thanks, queued.

-- Sebastian