[PATCH 5.15 03/42] power: supply: bq27xxx: Ensure power_supply_changed() is called on current sign changes

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Hans de Goede <hdegoede@redhat.com>

[ Upstream commit 939a116142012926e25de0ea6b7e2f8d86a5f1b6 ]

On gauges where the current register is signed, there is no charging
flag in the flags register. So only checking flags will not result
in power_supply_changed() getting called when e.g. a charger is plugged
in and the current sign changes from negative (discharging) to
positive (charging).

This causes userspace's notion of the status to lag until userspace
does a poll.

And when a power_supply_leds.c LED trigger is used to indicate charging
status with a LED, this LED will lag until the capacity percentage
changes, which may take many minutes (because the LED trigger only is
updated on power_supply_changed() calls).

Fix this by calling bq27xxx_battery_current_and_status() on gauges with
a signed current register and checking if the status has changed.

Fixes: 297a533b3e62 ("bq27x00: Cache battery registers")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/power/supply/bq27xxx_battery.c | 13 ++++++++++++-
 include/linux/power/bq27xxx_battery.h  |  3 +++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/power/supply/bq27xxx_battery.c b/drivers/power/supply/bq27xxx_battery.c
index 2fca4b9403ff9..e6d67655732aa 100644
--- a/drivers/power/supply/bq27xxx_battery.c
+++ b/drivers/power/supply/bq27xxx_battery.c
@@ -1836,6 +1836,7 @@ static int bq27xxx_battery_current_and_status(
 
 static void bq27xxx_battery_update_unlocked(struct bq27xxx_device_info *di)
 {
+	union power_supply_propval status = di->last_status;
 	struct bq27xxx_reg_cache cache = {0, };
 	bool has_singe_flag = di->opts & BQ27XXX_O_ZERO;
 
@@ -1860,14 +1861,24 @@ static void bq27xxx_battery_update_unlocked(struct bq27xxx_device_info *di)
 		if (di->regs[BQ27XXX_REG_CYCT] != INVALID_REG_ADDR)
 			cache.cycle_count = bq27xxx_battery_read_cyct(di);
 
+		/*
+		 * On gauges with signed current reporting the current must be
+		 * checked to detect charging <-> discharging status changes.
+		 */
+		if (!(di->opts & BQ27XXX_O_ZERO))
+			bq27xxx_battery_current_and_status(di, NULL, &status, &cache);
+
 		/* We only have to read charge design full once */
 		if (di->charge_design_full <= 0)
 			di->charge_design_full = bq27xxx_battery_read_dcap(di);
 	}
 
 	if ((di->cache.capacity != cache.capacity) ||
-	    (di->cache.flags != cache.flags))
+	    (di->cache.flags != cache.flags) ||
+	    (di->last_status.intval != status.intval)) {
+		di->last_status.intval = status.intval;
 		power_supply_changed(di->bat);
+	}
 
 	if (memcmp(&di->cache, &cache, sizeof(cache)) != 0)
 		di->cache = cache;
diff --git a/include/linux/power/bq27xxx_battery.h b/include/linux/power/bq27xxx_battery.h
index e3322dad9c85c..7c8d65414a70a 100644
--- a/include/linux/power/bq27xxx_battery.h
+++ b/include/linux/power/bq27xxx_battery.h
@@ -2,6 +2,8 @@
 #ifndef __LINUX_BQ27X00_BATTERY_H__
 #define __LINUX_BQ27X00_BATTERY_H__
 
+#include <linux/power_supply.h>
+
 enum bq27xxx_chip {
 	BQ27000 = 1, /* bq27000, bq27200 */
 	BQ27010, /* bq27010, bq27210 */
@@ -70,6 +72,7 @@ struct bq27xxx_device_info {
 	int charge_design_full;
 	bool removed;
 	unsigned long last_update;
+	union power_supply_propval last_status;
 	struct delayed_work work;
 	struct power_supply *bat;
 	struct list_head list;
-- 
2.39.2