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Commit 043957d6 authored by Anirudh Ghayal's avatar Anirudh Ghayal Committed by Gerrit - the friendly Code Review server
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power: vm-bms: Clamp SOC at v-cutoff during discharge 



Due to immaturities of the VBMS hw/sw there is a possibility
of SOC inaccuracy near the cutoff-voltage. In such cases
to avoid pre-mature reporting of SOC = 0, clamp the SOC to
1 if the VBMS calculated SOC is 0 and the battery voltage is
above the cutoff-voltage.

Change-Id: I11bdfec5a67ceead91412a20ea57dad2808228d8
Signed-off-by: default avatarAnirudh Ghayal <aghayal@codeaurora.org>
parent 635c5a56

drivers/power/qpnp-vm-bms.c

+29 −1
Original line number Diff line number Diff line 
/* Copyright (c) 2014, The Linux Foundation. All rights reserved.

/* Copyright (c) 2014-2015, The Linux Foundation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and
@@ -1989,6 +1989,31 @@ static void calculate_reported_soc(struct qpnp_bms_chip *chip) 
	power_supply_changed(&chip->bms_psy);

}



static int clamp_soc_based_on_voltage(struct qpnp_bms_chip *chip, int soc)

{

	int rc, vbat_uv;



	rc = get_battery_voltage(chip, &vbat_uv);

	if (rc < 0) {

		pr_err("adc vbat failed err = %d\n", rc);

		return soc;

	}



	/* only clamp when discharging */

	if (is_battery_charging(chip))

		return soc;



	if (soc <= 0 && vbat_uv > chip->dt.cfg_v_cutoff_uv) {

		pr_debug("clamping soc to 1, vbat (%d) > cutoff (%d)\n",

					vbat_uv, chip->dt.cfg_v_cutoff_uv);

		return 1;

	} else {

		pr_debug("not clamping, using soc = %d, vbat = %d and cutoff = %d\n",

				soc, vbat_uv, chip->dt.cfg_v_cutoff_uv);

		return soc;

	}

}



#define UI_SOC_CATCHUP_TIME	(60)

static void monitor_soc_work(struct work_struct *work)

{
@@ -2035,6 +2060,9 @@ static void monitor_soc_work(struct work_struct *work) 
			}

			new_soc = lookup_soc_ocv(chip, chip->last_ocv_uv,

								batt_temp);

			/* clamp soc due to BMS hw/sw immaturities */

			new_soc = clamp_soc_based_on_voltage(chip, new_soc);



			if (chip->calculated_soc != new_soc) {

				pr_debug("SOC changed! new_soc=%d prev_soc=%d\n",

						new_soc, chip->calculated_soc);