power: Add twl4030_madc battery driver.

This driver is used and tested on gta04 phone. It's using twl4030_madc
(similar to rx51 existing driver). Driver also implement charging and
discharging calibration data so user can define ranges and level.

Signed-off-by: Marek Belisko <[e-mail]>
Signed-off-by: Lukas Märdian <[e-mail]>
Signed-off-by: Anton Vorontsov <[e-mail]>

drivers/power/Kconfig

···
 	help
 	  Say Y here to enable support for iPAQ h1930/h1940/rx1950 battery
 
+config BATTERY_TWL4030_MADC
+	tristate "TWL4030 MADC battery driver"
+	depends on TWL4030_MADC
+	help
+	  Say Y here to enable this dumb driver for batteries managed
+	  through the TWL4030 MADC.
+
 config CHARGER_88PM860X
 	tristate "Marvell 88PM860x Charger driver"
 	depends on MFD_88PM860X && BATTERY_88PM860X

drivers/power/Makefile

···
 obj-$(CONFIG_BATTERY_MAX17042)	+= max17042_battery.o
 obj-$(CONFIG_BATTERY_Z2)	+= z2_battery.o
 obj-$(CONFIG_BATTERY_S3C_ADC)	+= s3c_adc_battery.o
+obj-$(CONFIG_BATTERY_TWL4030_MADC)	+= twl4030_madc_battery.o
 obj-$(CONFIG_CHARGER_88PM860X)	+= 88pm860x_charger.o
 obj-$(CONFIG_CHARGER_PCF50633)	+= pcf50633-charger.o
 obj-$(CONFIG_BATTERY_JZ4740)	+= jz4740-battery.o

drivers/power/twl4030_madc_battery.c

···
+/*
+ * Dumb driver for LiIon batteries using TWL4030 madc.
+ *
+ * Copyright 2013 Golden Delicious Computers
+ * Lukas Märdian <[e-mail]>
+ *
+ * Based on dumb driver for gta01 battery
+ * Copyright 2009 Openmoko, Inc
+ * Balaji Rao <[e-mail]>
+ */
+
+#include <linux/module.h>
+#include <linux/param.h>
+#include <linux/delay.h>
+#include <linux/workqueue.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/slab.h>
+#include <linux/sort.h>
+#include <linux/i2c/twl4030-madc.h>
+#include <linux/power/twl4030_madc_battery.h>
+
+struct twl4030_madc_battery {
+	struct power_supply psy;
+	struct twl4030_madc_bat_platform_data *pdata;
+};
+
+static enum power_supply_property twl4030_madc_bat_props[] = {
+	POWER_SUPPLY_PROP_PRESENT,
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_TECHNOLOGY,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_CURRENT_NOW,
+	POWER_SUPPLY_PROP_CAPACITY,
+	POWER_SUPPLY_PROP_CHARGE_FULL,
+	POWER_SUPPLY_PROP_CHARGE_NOW,
+	POWER_SUPPLY_PROP_TEMP,
+	POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
+};
+
+static int madc_read(int index)
+{
+	struct twl4030_madc_request req;
+	int val;
+
+	req.channels = index;
+	req.method = TWL4030_MADC_SW2;
+	req.type = TWL4030_MADC_WAIT;
+	req.do_avg = 0;
+	req.raw = false;
+	req.func_cb = NULL;
+
+	val = twl4030_madc_conversion(&req);
+	if (val < 0)
+		return val;
+
+	return req.rbuf[ffs(index) - 1];
+}
+
+static int twl4030_madc_bat_get_charging_status(void)
+{
+	return (madc_read(TWL4030_MADC_ICHG) > 0) ? 1 : 0;
+}
+
+static int twl4030_madc_bat_get_voltage(void)
+{
+	return madc_read(TWL4030_MADC_VBAT);
+}
+
+static int twl4030_madc_bat_get_current(void)
+{
+	return madc_read(TWL4030_MADC_ICHG) * 1000;
+}
+
+static int twl4030_madc_bat_get_temp(void)
+{
+	return madc_read(TWL4030_MADC_BTEMP) * 10;
+}
+
+static int twl4030_madc_bat_voltscale(struct twl4030_madc_battery *bat,
+					int volt)
+{
+	struct twl4030_madc_bat_calibration *calibration;
+	int i, res = 0;
+
+	/* choose charging curve */
+	if (twl4030_madc_bat_get_charging_status())
+		calibration = bat->pdata->charging;
+	else
+		calibration = bat->pdata->discharging;
+
+	if (volt > calibration[0].voltage) {
+		res = calibration[0].level;
+	} else {
+		for (i = 0; calibration[i+1].voltage >= 0; i++) {
+			if (volt <= calibration[i].voltage &&
+					volt >= calibration[i+1].voltage) {
+				/* interval found - interpolate within range */
+				res = calibration[i].level -
+					((calibration[i].voltage - volt) *
+					(calibration[i].level -
+					calibration[i+1].level)) /
+					(calibration[i].voltage -
+					calibration[i+1].voltage);
+				break;
+			}
+		}
+	}
+	return res;
+}
+
+static int twl4030_madc_bat_get_property(struct power_supply *psy,
+					enum power_supply_property psp,
+					union power_supply_propval *val)
+{
+	struct twl4030_madc_battery *bat = container_of(psy,
+					struct twl4030_madc_battery, psy);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_STATUS:
+		if (twl4030_madc_bat_voltscale(bat,
+				twl4030_madc_bat_get_voltage()) > 95)
+			val->intval = POWER_SUPPLY_STATUS_FULL;
+		else {
+			if (twl4030_madc_bat_get_charging_status())
+				val->intval = POWER_SUPPLY_STATUS_CHARGING;
+			else
+				val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+		}
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		val->intval = twl4030_madc_bat_get_voltage() * 1000;
+		break;
+	case POWER_SUPPLY_PROP_TECHNOLOGY:
+		val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
+		break;
+	case POWER_SUPPLY_PROP_CURRENT_NOW:
+		val->intval = twl4030_madc_bat_get_current();
+		break;
+	case POWER_SUPPLY_PROP_PRESENT:
+		/* assume battery is always present */
+		val->intval = 1;
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_NOW: {
+			int percent = twl4030_madc_bat_voltscale(bat,
+					twl4030_madc_bat_get_voltage());
+			val->intval = (percent * bat->pdata->capacity) / 100;
+			break;
+		}
+	case POWER_SUPPLY_PROP_CAPACITY:
+		val->intval = twl4030_madc_bat_voltscale(bat,
+					twl4030_madc_bat_get_voltage());
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_FULL:
+		val->intval = bat->pdata->capacity;
+		break;
+	case POWER_SUPPLY_PROP_TEMP:
+		val->intval = twl4030_madc_bat_get_temp();
+		break;
+	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW: {
+			int percent = twl4030_madc_bat_voltscale(bat,
+					twl4030_madc_bat_get_voltage());
+			/* in mAh */
+			int chg = (percent * (bat->pdata->capacity/1000))/100;
+
+			/* assume discharge with 400 mA (ca. 1.5W) */
+			val->intval = (3600l * chg) / 400;
+			break;
+		}
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void twl4030_madc_bat_ext_changed(struct power_supply *psy)
+{
+	struct twl4030_madc_battery *bat = container_of(psy,
+					struct twl4030_madc_battery, psy);
+
+	power_supply_changed(&bat->psy);
+}
+
+static int twl4030_cmp(const void *a, const void *b)
+{
+	return ((struct twl4030_madc_bat_calibration *)b)->voltage -
+		((struct twl4030_madc_bat_calibration *)a)->voltage;
+}
+
+static int twl4030_madc_battery_probe(struct platform_device *pdev)
+{
+	struct twl4030_madc_battery *twl4030_madc_bat;
+	struct twl4030_madc_bat_platform_data *pdata = pdev->dev.platform_data;
+
+	twl4030_madc_bat = kzalloc(sizeof(*twl4030_madc_bat), GFP_KERNEL);
+	if (!twl4030_madc_bat)
+		return -ENOMEM;
+
+	twl4030_madc_bat->psy.name = "twl4030_battery";
+	twl4030_madc_bat->psy.type = POWER_SUPPLY_TYPE_BATTERY;
+	twl4030_madc_bat->psy.properties = twl4030_madc_bat_props;
+	twl4030_madc_bat->psy.num_properties =
+					ARRAY_SIZE(twl4030_madc_bat_props);
+	twl4030_madc_bat->psy.get_property = twl4030_madc_bat_get_property;
+	twl4030_madc_bat->psy.external_power_changed =
+					twl4030_madc_bat_ext_changed;
+
+	/* sort charging and discharging calibration data */
+	sort(pdata->charging, pdata->charging_size,
+		sizeof(struct twl4030_madc_bat_calibration),
+		twl4030_cmp, NULL);
+	sort(pdata->discharging, pdata->discharging_size,
+		sizeof(struct twl4030_madc_bat_calibration),
+		twl4030_cmp, NULL);
+
+	twl4030_madc_bat->pdata = pdata;
+	platform_set_drvdata(pdev, twl4030_madc_bat);
+	power_supply_register(&pdev->dev, &twl4030_madc_bat->psy);
+
+	return 0;
+}
+
+static int twl4030_madc_battery_remove(struct platform_device *pdev)
+{
+	struct twl4030_madc_battery *bat = platform_get_drvdata(pdev);
+
+	power_supply_unregister(&bat->psy);
+	kfree(bat);
+
+	return 0;
+}
+
+static struct platform_driver twl4030_madc_battery_driver = {
+	.driver = {
+		.name = "twl4030_madc_battery",
+	},
+	.probe  = twl4030_madc_battery_probe,
+	.remove = twl4030_madc_battery_remove,
+};
+module_platform_driver(twl4030_madc_battery_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Lukas Märdian <[e-mail]>");
+MODULE_DESCRIPTION("twl4030_madc battery driver");

include/linux/power/twl4030_madc_battery.h

···
+/*
+ * Dumb driver for LiIon batteries using TWL4030 madc.
+ *
+ * Copyright 2013 Golden Delicious Computers
+ * Nikolaus Schaller <[e-mail]>
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation;  either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#ifndef __TWL4030_MADC_BATTERY_H
+#define __TWL4030_MADC_BATTERY_H
+
+/*
+ * Usually we can assume 100% @ 4.15V and 0% @ 3.3V but curves differ for
+ * charging and discharging!
+ */
+
+struct twl4030_madc_bat_calibration {
+	short voltage;	/* in mV - specify -1 for end of list */
+	short level;	/* in percent (0 .. 100%) */
+};
+
+struct twl4030_madc_bat_platform_data {
+	unsigned int capacity;	/* total capacity in uAh */
+	struct twl4030_madc_bat_calibration *charging;
+	int charging_size;
+	struct twl4030_madc_bat_calibration *discharging;
+	int discharging_size;
+};
+
+#endif