[PATCH 1/1] sunxi: Add option to prevent power-on when plug in

[Chris Morgan <macroalpha82@gmail.com>]

From: Chris Morgan <macromorgan@hotmail.com>

For sunxi boards with the AXP209, AXP221, AXP809, and AXP818 PMICs
(plus possibly others, I only confirmed the datasheets for these),
it is sometimes desirable to not power up whenever the device is
plugged in. An example would be when using the NTC CHIP inside a
PocketCHIP. This provides a configurable option to check if bit 0 of
register 0 of the PMIC says it was powered because of a power button
press (0) or a plug-in event (1). If the value is 1 and this option
is selected, the device shuts down shortly after printing a message
to console stating the reason why it's shutting down. Powering up the
board with the power button is not affected.

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
---
 arch/arm/mach-sunxi/Kconfig | 10 ++++++++++
 board/sunxi/board.c         | 17 ++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/arch/arm/mach-sunxi/Kconfig b/arch/arm/mach-sunxi/Kconfig
index 2c18cf02d1..d94046dc54 100644
--- a/arch/arm/mach-sunxi/Kconfig
+++ b/arch/arm/mach-sunxi/Kconfig
@@ -785,6 +785,16 @@ config AXP_GPIO
 	---help---
 	Say Y here to enable support for the gpio pins of the axp PMIC ICs.
 
+config AXP_DISABLE_POWERON_VIN
+	bool "Disable device power-on when plugged in"
+	depends on AXP209_POWER || AXP221_POWER || AXP809_POWER || AXP818_POWER
+	default n
+	---help---
+	  Say Y here to prevent the device from powering up because of a plug-in
+	  event. When set, the device will power on briefly to determine why it
+	  was powered on, and if it was determined because of a plug-in event
+	  instead of a button press event it will shut back off.
+
 config VIDEO_SUNXI
 	bool "Enable graphical uboot console on HDMI, LCD or VGA"
 	depends on !MACH_SUN8I_A83T
diff --git a/board/sunxi/board.c b/board/sunxi/board.c
index fdbcd40269..9f656b56f1 100644
--- a/board/sunxi/board.c
+++ b/board/sunxi/board.c
@@ -27,6 +27,7 @@
 #include <asm/arch/dram.h>
 #include <asm/arch/mmc.h>
 #include <asm/arch/prcm.h>
+#include <asm/arch/pmic_bus.h>
 #include <asm/arch/spl.h>
 #include <asm/global_data.h>
 #include <linux/delay.h>
@@ -586,6 +587,7 @@ static void sunxi_spl_store_dram_size(phys_addr_t dram_size)
 void sunxi_board_init(void)
 {
 	int power_failed = 0;
+	__maybe_unused u8 boot_reason;
 
 #ifdef CONFIG_LED_STATUS
 	if (IS_ENABLED(CONFIG_SPL_DRIVERS_MISC))
@@ -601,6 +603,21 @@ void sunxi_board_init(void)
 	defined CONFIG_AXP809_POWER || defined CONFIG_AXP818_POWER
 	power_failed = axp_init();
 
+#if IS_ENABLED(CONFIG_AXP_DISABLE_POWERON_VIN)
+/* This behavior (bit(0) of register 0x00 and shutdown by setting bit(7) of
+ * register 0x32 appears to be common to many AXP chips, at least according to
+ * the datasheets of the AXP209, the AXP221, the AXP803, the AXP809, and the
+ * AXP818.
+ */
+	if (!power_failed) {
+		pmic_bus_read(AXP_POWER_STATUS, &boot_reason);
+		if (boot_reason & BIT(0)) {
+			printf("Power on by charger, shutting down.\n");
+			pmic_bus_write(0x32, BIT(7));
+		}
+	}
+#endif
+
 #if defined CONFIG_AXP221_POWER || defined CONFIG_AXP809_POWER || \
 	defined CONFIG_AXP818_POWER
 	power_failed |= axp_set_dcdc1(CONFIG_AXP_DCDC1_VOLT);
-- 
2.30.2