[PATCH V2 3/4] power: supply: rk817-charger: Clear SYS_CAN_SD register by default

[Chris Morgan]

From: Chris Morgan <macromorgan at hotmail.com>

The BSP driver for the rk817 charger by default clears the SYS_CAN_SD.
This register tells the PMIC that the system voltage can be shut down in
battery off mode. Though the BSP driver also included a way to bypass
this behavior, no boards have been observed using the override.

When this register is not cleared, it can result in a persistent power
drain on certain devices while the device is off, as observed by users.

Fixes: 11cb8da0189b ("power: supply: Add charger driver for Rockchip RK817")
Signed-off-by: Chris Morgan <macromorgan at hotmail.com>
Suggested-by: Zetarancio <zetarancio at users.noreply.github.com>
---
 drivers/power/supply/rk817_charger.c | 9 +++++++++
 include/linux/mfd/rk808.h            | 1 +
 2 files changed, 10 insertions(+)

diff --git a/drivers/power/supply/rk817_charger.c b/drivers/power/supply/rk817_charger.c
index 0c7287ad27c6..d7d367211d5e 100644
--- a/drivers/power/supply/rk817_charger.c
+++ b/drivers/power/supply/rk817_charger.c
@@ -1166,6 +1166,15 @@ static int rk817_battery_init(struct rk817_charger *charger,
 	regmap_write_bits(rk808->regmap, RK817_PMIC_CHRG_IN, RK817_USB_ILIM_EN,
 			  (0x01 << 3));
 
+	/*
+	 * Do not shut down the system voltage in bat_off mode. The BSP driver
+	 * cleared this bit for all devices unless a specific device tree
+	 * parameter was used, however I have yet to see such parameter on any
+	 * device.
+	 */
+	regmap_clear_bits(rk808->regmap,
+			  RK817_PMIC_CHRG_TERM, RK817_SYS_CAN_SD);
+
 	return 0;
 }
 
diff --git a/include/linux/mfd/rk808.h b/include/linux/mfd/rk808.h
index 72419d311626..2bc58de53d82 100644
--- a/include/linux/mfd/rk808.h
+++ b/include/linux/mfd/rk808.h
@@ -1297,6 +1297,7 @@ enum rk809_reg_id {
 #define RK817_USB_ILIM_EN		(0x01 << 3)
 #define RK817_USB_ILIM_SEL		(0x07 << 0)
 #define RK817_PMIC_CHRG_TERM		0xe6
+#define RK817_SYS_CAN_SD		(0x01 << 7)
 #define RK817_CHRG_TERM_ANA_DIG		(0x01 << 2)
 #define RK817_CHRG_TERM_ANA_SEL		(0x03 << 0)
 #define RK817_CHRG_EN			(0x01 << 6)
-- 
2.53.0