power: pm8921-bms: Enable batt alarm

Set the batt alarm to wake up the system if the
battery voltage falls below a threshold. This is to
make sure that the device does not shutdown abruptly
without any notification.

Hold the low voltage wakelock to prevent the device
from going to sleep immediately after the low voltage
notification.

Change-Id: Ifaeeeb27bd85f9c95f026ac3565681432e247b02
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>

arch/arm/mach-msm/board-8064-pmic.c

@@ -473,6 +473,8 @@ apq8064_pm8921_bms_pdata __devinitdata = {
 	.chg_term_ua			= CHG_TERM_MA * 1000,
 	.normal_voltage_calc_ms		= 20000,
 	.low_voltage_calc_ms		= 1000,
+	.alarm_low_mv			= 3400,
+	.alarm_high_mv			= 4000,
 };
 
 static struct pm8921_platform_data

arch/arm/mach-msm/board-8930-pmic.c

@@ -476,6 +476,8 @@ static struct pm8921_bms_platform_data pm8921_bms_pdata __devinitdata = {
 	.rconn_mohm			= 18,
 	.normal_voltage_calc_ms		= 20000,
 	.low_voltage_calc_ms		= 1000,
+	.alarm_low_mv			= 3400,
+	.alarm_high_mv			= 4000,
 };
 
 static struct pm8038_platform_data pm8038_platform_data __devinitdata = {

arch/arm/mach-msm/board-8960-pmic.c

-/* Copyright (c) 2011-2012, Code Aurora Forum. All rights reserved.
+/* Copyright (c) 2011-2013, 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
@@ -433,6 +433,8 @@ static struct pm8921_bms_platform_data pm8921_bms_pdata __devinitdata = {
 	.chg_term_ua			= CHG_TERM_MA * 1000,
 	.normal_voltage_calc_ms		= 20000,
 	.low_voltage_calc_ms		= 1000,
+	.alarm_low_mv			= 3400,
+	.alarm_high_mv			= 4000,
 };
 
 #define	PM8921_LC_LED_MAX_CURRENT	4	/* I = 4mA */

drivers/power/pm8921-bms.c

@@ -23,6 +23,7 @@
 #include <linux/mfd/pm8xxx/pm8921-charger.h>
 #include <linux/mfd/pm8xxx/ccadc.h>
 #include <linux/mfd/pm8xxx/batterydata-lib.h>
+#include <linux/mfd/pm8xxx/batt-alarm.h>
 #include <linux/interrupt.h>
 #include <linux/bitops.h>
 #include <linux/debugfs.h>
@@ -120,6 +121,9 @@ struct pm8921_bms_chip {
 	unsigned int		charging_began;
 	unsigned int		start_percent;
 	unsigned int		end_percent;
+	unsigned int		alarm_low_mv;
+	unsigned int		alarm_high_mv;
+
 	int			charge_time_us;
 	int			catch_up_time_us;
 	enum battery_type	batt_type;
@@ -192,6 +196,13 @@ static int last_soc = -EINVAL;
 static int last_real_fcc_mah = -EINVAL;
 static int last_real_fcc_batt_temp = -EINVAL;
 
+static int pm8921_battery_gauge_alarm_notify(struct notifier_block *nb,
+				unsigned long status, void *unused);
+
+static struct notifier_block alarm_notifier = {
+	.notifier_call = pm8921_battery_gauge_alarm_notify,
+};
+
 static int bms_ops_set(const char *val, const struct kernel_param *kp)
 {
 	if (*(int *)kp->arg == -EINVAL)
@@ -379,6 +390,124 @@ static int usb_chg_plugged_in(struct pm8921_bms_chip *chip)
 	return val;
 }
 
+static int pm8921_bms_enable_batt_alarm(struct pm8921_bms_chip *chip)
+{
+	int rc = 0;
+
+	rc = pm8xxx_batt_alarm_enable(PM8XXX_BATT_ALARM_LOWER_COMPARATOR);
+	if (!rc)
+		rc = pm8xxx_batt_alarm_disable(
+				PM8XXX_BATT_ALARM_UPPER_COMPARATOR);
+	if (rc) {
+		pr_err("unable to set batt alarm state rc=%d\n", rc);
+		return rc;
+	}
+
+	return rc;
+}
+
+static int pm8921_bms_configure_batt_alarm(struct pm8921_bms_chip *chip)
+{
+	int rc = 0;
+
+	rc = pm8xxx_batt_alarm_disable(PM8XXX_BATT_ALARM_UPPER_COMPARATOR);
+	if (!rc)
+		rc = pm8xxx_batt_alarm_disable(
+			PM8XXX_BATT_ALARM_LOWER_COMPARATOR);
+	if (rc) {
+		pr_err("unable to set batt alarm state rc=%d\n", rc);
+		return rc;
+	}
+
+	/*
+	* The batt-alarm driver requires sane values for both min / max,
+	* regardless of whether they're both activated.
+	*/
+	rc = pm8xxx_batt_alarm_threshold_set(
+			PM8XXX_BATT_ALARM_LOWER_COMPARATOR,
+					chip->alarm_low_mv);
+	if (!rc)
+		rc = pm8xxx_batt_alarm_threshold_set(
+			PM8XXX_BATT_ALARM_UPPER_COMPARATOR,
+					chip->alarm_high_mv);
+	if (rc) {
+		pr_err("unable to set batt alarm threshold rc=%d\n", rc);
+		return rc;
+	}
+
+	rc = pm8xxx_batt_alarm_hold_time_set(
+			PM8XXX_BATT_ALARM_HOLD_TIME_16_MS);
+	if (rc) {
+		pr_err("unable to set batt alarm hold time rc=%d\n", rc);
+		return rc;
+	}
+
+	/* PWM enabled at 2Hz */
+	rc = pm8xxx_batt_alarm_pwm_rate_set(1, 7, 4);
+	if (rc) {
+		pr_err("unable to set batt alarm pwm rate rc=%d\n", rc);
+		return rc;
+	}
+
+	rc = pm8xxx_batt_alarm_register_notifier(&alarm_notifier);
+	if (rc) {
+		pr_err("unable to register alarm notifier rc=%d\n", rc);
+		return rc;
+	}
+
+	return rc;
+}
+
+static int pm8921_battery_gauge_alarm_notify(struct notifier_block *nb,
+		unsigned long status, void *unused)
+{
+	int rc;
+
+	if (!the_chip) {
+		pr_err("not initialized\n");
+		return -EINVAL;
+	}
+
+	switch (status) {
+	case 0:
+		pr_debug("spurious interrupt\n");
+		break;
+	case 1:
+		pr_debug("Low voltage alarm triggered\n");
+		/*
+		 * hold the low voltage wakelock until the soc
+		 * work finds it appropriate to release it.
+		 */
+		wake_lock(&the_chip->low_voltage_wake_lock);
+		the_chip->low_voltage_wake_lock_held = 1;
+
+		rc = pm8xxx_batt_alarm_disable(
+				PM8XXX_BATT_ALARM_LOWER_COMPARATOR);
+		if (!rc)
+			rc = pm8xxx_batt_alarm_enable(
+				PM8XXX_BATT_ALARM_UPPER_COMPARATOR);
+		if (rc)
+			pr_err("unable to set alarm state rc=%d\n", rc);
+		break;
+	case 2:
+		rc = pm8xxx_batt_alarm_disable(
+			PM8XXX_BATT_ALARM_UPPER_COMPARATOR);
+		if (!rc)
+			rc = pm8xxx_batt_alarm_enable(
+				PM8XXX_BATT_ALARM_LOWER_COMPARATOR);
+		if (rc)
+			pr_err("unable to set alarm state rc=%d\n", rc);
+
+		break;
+	default:
+		pr_err("error received\n");
+		break;
+	}
+
+	return 0;
+};
+
+
 #define HOLD_OREG_DATA		BIT(1)
 static int pm_bms_lock_output_data(struct pm8921_bms_chip *chip)
 {
@@ -1599,6 +1728,7 @@ static int charging_adjustments(struct pm8921_bms_chip *chip,
 static void very_low_voltage_check(struct pm8921_bms_chip *chip,
 					int ibat_ua, int vbat_uv)
 {
+	int rc;
 	/*
 	 * if battery is very low (v_cutoff voltage + 20mv) hold
 	 * a wakelock untill soc = 0%
@@ -1617,6 +1747,9 @@ static void very_low_voltage_check(struct pm8921_bms_chip *chip,
 		chip->low_voltage_wake_lock_held = 0;
 		wake_unlock(&chip->low_voltage_wake_lock);
 		chip->soc_calc_period = chip->normal_voltage_calc_ms;
+		rc = pm8921_bms_enable_batt_alarm(chip);
+		if (rc)
+			pr_err("Unable to enable batt alarm\n");
 	}
 }
 
@@ -3148,6 +3281,9 @@ static int __devinit pm8921_bms_probe(struct platform_device *pdev)
 	chip->ocv_dis_high_soc = pdata->ocv_dis_high_soc;
 	chip->ocv_dis_low_soc = pdata->ocv_dis_low_soc;
 
+	chip->alarm_low_mv = pdata->alarm_low_mv;
+	chip->alarm_high_mv = pdata->alarm_high_mv;
+
 	mutex_init(&chip->calib_mutex);
 	INIT_WORK(&chip->calib_hkadc_work, calibrate_hkadc_work);
 
@@ -3188,6 +3324,18 @@ static int __devinit pm8921_bms_probe(struct platform_device *pdev)
 	pm8921_bms_enable_irq(chip, PM8921_BMS_GOOD_OCV);
 	pm8921_bms_enable_irq(chip, PM8921_BMS_OCV_FOR_R);
 
+	rc = pm8921_bms_configure_batt_alarm(chip);
+	if (rc) {
+		pr_err("Couldn't configure battery alarm! rc=%d\n", rc);
+		goto free_irqs;
+	}
+
+	rc = pm8921_bms_enable_batt_alarm(chip);
+	if (rc) {
+		pr_err("Couldn't enable battery alarm! rc=%d\n", rc);
+		goto free_irqs;
+	}
+
 	calculate_soc_work(&(chip->calculate_soc_delayed_work.work));
 
 	rc = get_battery_uvolts(chip, &vbatt);

include/linux/mfd/pm8xxx/pm8921-bms.h

@@ -53,6 +53,8 @@ struct pm8921_bms_platform_data {
 	unsigned int			v_cutoff;
 	unsigned int			max_voltage_uv;
 	unsigned int			rconn_mohm;
+	unsigned int			alarm_low_mv;
+	unsigned int			alarm_high_mv;
 	int				enable_fcc_learning;
 	int				shutdown_soc_valid_limit;
 	int				ignore_shutdown_soc;