[PATCH 02/15] power: supply: ab8500_fg: Report sub-percent charge changes

[Linus Walleij <linusw@kernel.org>]

The fuel gauge updates bat_cap.mah from the coulomb counter but exposes
bat_cap.prev_mah through CHARGE_NOW and ENERGY_NOW. It only refreshes
prev_mah when the rounded integer capacity percentage changes, making the
momentary properties appear frozen between percentage steps.

Refresh prev_mah and notify userspace whenever the new charge remains
within the currently accepted percentage. If a discharge estimate tries
to cross upward into a higher percentage, the existing rejection still
leaves both the reported percentage and charge unchanged.

The AB8500 fuel-gauge implementations in the Samsung-GT-I8160-Codina,
Samsung-GT-I8160_HD-Codina, Samsung-GT-I8530-Gavini,
Samsung-GT-S7710-Skomer, Samsung-SGH-I407-Kyle and
Samsung-SGH-T599-Codina-TMO product trees retain the same percentage-gated
prev_mah update and contain no finer-grained reporting workaround.

Fixes: 13151631b5bd ("ab8500-fg: A8500 fuel gauge driver")
Cc: stable@vger.kernel.org
Assisted-by: LLM
Signed-off-by: Linus Walleij <linusw@kernel.org>
---
 drivers/power/supply/ab8500_fg.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/power/supply/ab8500_fg.c b/drivers/power/supply/ab8500_fg.c
index 016ed35e90f9..c5eaa32c4a2d 100644
--- a/drivers/power/supply/ab8500_fg.c
+++ b/drivers/power/supply/ab8500_fg.c
@@ -1387,6 +1387,13 @@ static void ab8500_fg_check_capacity_limits(struct ab8500_fg *di, bool init)
 		}
 	}
 
+	/* Keep the charge properties current between percentage changes. */
+	if (di->bat_cap.prev_percent == percent &&
+	    di->bat_cap.prev_mah != di->bat_cap.mah) {
+		di->bat_cap.prev_mah = di->bat_cap.mah;
+		changed = true;
+	}
+
 	if (changed) {
 		if (di->bm->capacity_scaling) {
 			di->bat_cap.cap_scale.scaled_cap =

-- 
2.55.0