openwrt-xburst/target/linux/omap24xx/patches-3.3/900-n810-battery-management.patch

--- a/drivers/cbus/Kconfig
+++ b/drivers/cbus/Kconfig
@@ -83,4 +83,12 @@ config CBUS_RETU_HEADSET
 
 endif # CBUS_RETU
 
+config N810BM
+	depends on CBUS_RETU && CBUS_TAHVO
+	tristate "Nokia n810 battery management"
+	---help---
+	  Nokia n810 device battery management.
+
+	  If unsure, say N.
+
 endmenu
--- a/drivers/cbus/Makefile
+++ b/drivers/cbus/Makefile
@@ -11,3 +11,6 @@ obj-$(CONFIG_CBUS_RETU_POWERBUTTON) += r
 obj-$(CONFIG_CBUS_RETU_RTC)	+= retu-rtc.o
 obj-$(CONFIG_CBUS_RETU_WDT)	+= retu-wdt.o
 obj-$(CONFIG_CBUS_RETU_HEADSET)	+= retu-headset.o
+n810bm-y			+= n810bm_main.o
+n810bm-y			+= lipocharge.o
+obj-$(CONFIG_N810BM)		+= n810bm.o
--- /dev/null
+++ b/drivers/cbus/n810bm_main.c
@@ -0,0 +1,1572 @@
+/*
+ *   Nokia n810 battery management
+ *
+ *   WARNING: This driver is based on unconfirmed documentation.
+ *            It is possibly dangerous to use this software.
+ *            Use this software at your own risk!
+ *
+ *   Copyright (c) 2010-2011 Michael Buesch <mb@bu3sch.de>
+ *
+ *   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.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#define DEBUG
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/timer.h>
+#include <linux/firmware.h>
+#include <linux/bitops.h>
+#include <linux/workqueue.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+
+#include "cbus.h"
+#include "retu.h"
+#include "tahvo.h"
+#include "lipocharge.h"
+
+
+#define N810BM_PMM_BLOCK_FILENAME	"n810-cal-bme-pmm.fw"
+#define N810BM_PMM_BLOCK_SIZE		0x600
+#define N810BM_PMM_GROUP_SIZE		0x200
+#define N810BM_PMM_ELEM_SIZE		0x10
+
+#define N810BM_CHECK_INTERVAL		(HZ * 2)
+#define N810BM_MIN_VOLTAGE_THRES	3200 /* Absolute minimum voltage threshold */
+
+
+/* RETU_ADC_BSI
+ * The battery size indicator ADC measures the resistance between
+ * the battery BSI pin and ground. This is used to detect the battery
+ * capacity, as the BSI resistor is related to capacity.
+ *
+ * Manually measured lookup table.
+ * Hard to measure, thus not very accurate.
+ *
+ * Resistance  |  ADC value
+ * ========================
+ * 120k        |  0x3AC
+ * 110k        |  0x37C
+ * 100k        |  0x351
+ *  90k        |  0x329
+ */
+
+/* RETU_ADC_BATTVOLT
+ * Manually measured lookup table.
+ * Hard to measure, thus not very accurate.
+ *
+ * Voltage  |  ADC value
+ * =====================
+ * 2.80V    |  0x037
+ * 2.90V    |  0x05E
+ * 3.00V    |  0x090
+ * 3.10V    |  0x0A4
+ * 3.20V    |  0x0CC
+ * 3.30V    |  0x0EF
+ * 3.40V    |  0x115
+ * 3.50V    |  0x136
+ * 3.60V    |  0x15C
+ * 3.70V    |  0x187
+ * 3.80V    |  0x1A5
+ * 3.90V    |  0x1C9
+ * 4.00V    |  0x1ED
+ * 4.10V    |  0x212
+ * 4.20V    |  0x236
+ */
+
+
+/* PMM block ADC IDs */
+enum n810bm_pmm_adc_id {
+	N810BM_PMM_ADC_BATVOLT		= 0x01,	/* Battery voltage */
+	N810BM_PMM_ADC_CHGVOLT		= 0x02,	/* Charger voltage */
+	N810BM_PMM_ADC_GND2		= 0x03,	/* Ground 0V */
+	N810BM_PMM_ADC_BSI		= 0x04,	/* Battery size indicator */
+	N810BM_PMM_ADC_BATTEMP		= 0x05,	/* Battery temperature */
+	N810BM_PMM_ADC_HEADSET		= 0x06,	/* Headset detection */
+	N810BM_PMM_ADC_HOOKDET		= 0x07,	/* Hook detection */
+	N810BM_PMM_ADC_LIGHTSENS	= 0x08,	/* Light sensor */
+	N810BM_PMM_ADC_BATCURR		= 0x0E,	/* Battery current */
+	N810BM_PMM_ADC_BKUPVOLT		= 0x13,	/* Backup battery voltage */
+	N810BM_PMM_ADC_LIGHTTEMP	= 0x14,	/* Light sensor temperature */
+	N810BM_PMM_ADC_RFGP		= 0x15,	/* RF GP */
+	N810BM_PMM_ADC_WBTX		= 0x16,	/* Wideband TX detection */
+	N810BM_PMM_ADC_RETUTEMP		= 0x17,	/* RETU chip temperature */
+	N810BM_PMM_ADC_0xFE		= 0xFE,
+};
+
+struct n810bm_adc_calib {
+	enum n810bm_pmm_adc_id id;
+	u8 flags;
+	u8 adc_groupnr;
+	u32 field1;
+	u32 field2;
+	u16 field3;
+	u16 field4;
+};
+
+struct n810bm_calib {
+	struct n810bm_adc_calib adc[25];
+};
+
+enum n810bm_capacity {
+	N810BM_CAP_UNKNOWN	= -1,
+	N810BM_CAP_NONE		= 0,
+	N810BM_CAP_1500MAH	= 1500,	/* 1500 mAh battery */
+};
+
+enum n810bm_notify_flags {
+	N810BM_NOTIFY_charger_present,
+	N810BM_NOTIFY_charger_state,
+	N810BM_NOTIFY_charger_pwm,
+};
+
+struct n810bm {
+	int tahvo_irq;
+	bool tahvo_irq_enabled;
+
+	bool battery_present;			/* A battery is inserted */
+	bool charger_present;			/* The charger is connected */
+	enum n810bm_capacity capacity;		/* The capacity of the inserted battery (if any) */
+
+	bool charger_enabled;			/* Want to charge? */
+	struct lipocharge charger;		/* Charger subsystem */
+	unsigned int active_current_pwm;	/* Active value of TAHVO_REG_CHGCURR */
+	int current_measure_enabled;		/* Current measure enable refcount */
+
+	struct platform_device *pdev;
+	struct n810bm_calib calib;		/* Calibration data */
+
+	bool verbose_charge_log;		/* Verbose charge logging */
+
+	unsigned long notify_flags;
+	struct work_struct notify_work;
+	struct delayed_work periodic_check_work;
+
+	bool initialized;			/* The hardware was initialized */
+	struct mutex mutex;
+};
+
+static void n810bm_notify_charger_present(struct n810bm *bm);
+static void n810bm_notify_charger_state(struct n810bm *bm);
+static void n810bm_notify_charger_pwm(struct n810bm *bm);
+
+
+static struct platform_device *n810bm_retu_device;
+static struct platform_device *n810bm_tahvo_device;
+
+
+static inline struct n810bm * device_to_n810bm(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct n810bm *bm = platform_get_drvdata(pdev);
+
+	return bm;
+}
+
+static inline bool n810bm_known_battery_present(struct n810bm *bm)
+{
+	return bm->battery_present &&
+	       bm->capacity != N810BM_CAP_UNKNOWN &&
+	       bm->capacity != N810BM_CAP_NONE;
+}
+
+static void n810bm_emergency(struct n810bm *bm, const char *message) __noreturn;
+static void n810bm_emergency(struct n810bm *bm, const char *message)
+{
+	printk(KERN_EMERG "n810 battery management fatal fault: %s\n", message);
+	cbus_emergency();
+}
+
+static u16 tahvo_read(struct n810bm *bm, unsigned int reg)
+{
+	return tahvo_read_reg(&n810bm_tahvo_device->dev, reg);
+}
+
+static void tahvo_maskset(struct n810bm *bm, unsigned int reg, u16 mask, u16 set)
+{
+	tahvo_set_clear_reg_bits(&n810bm_tahvo_device->dev, reg, set, mask);
+}
+
+static inline void tahvo_write(struct n810bm *bm, unsigned int reg, u16 value)
+{
+	tahvo_write_reg(&n810bm_tahvo_device->dev, reg, value);
+}
+
+static inline void tahvo_set(struct n810bm *bm, unsigned int reg, u16 mask)
+{
+	tahvo_set_clear_reg_bits(&n810bm_tahvo_device->dev, reg, mask, mask);
+}
+
+static inline void tahvo_clear(struct n810bm *bm, unsigned int reg, u16 mask)
+{
+	tahvo_set_clear_reg_bits(&n810bm_tahvo_device->dev, reg, 0, mask);
+}
+
+static u16 retu_read(struct n810bm *bm, unsigned int reg)
+{
+	return retu_read_reg(&n810bm_retu_device->dev, reg);
+}
+
+static void retu_maskset(struct n810bm *bm, unsigned int reg, u16 mask, u16 set)
+{
+	retu_set_clear_reg_bits(&n810bm_retu_device->dev, reg, set, mask);
+}
+
+static inline void retu_write(struct n810bm *bm, unsigned int reg, u16 value)
+{
+	retu_write_reg(&n810bm_retu_device->dev, reg, value);
+}
+
+static int retu_adc_average(struct n810bm *bm, unsigned int chan,
+			    unsigned int nr_passes)
+{
+	unsigned int i, value = 0;
+	int ret;
+
+	if (WARN_ON(!nr_passes))
+		return 0;
+	for (i = 0; i < nr_passes; i++) {
+		ret = retu_read_adc(&n810bm_retu_device->dev, chan);
+		if (ret < 0)
+			return ret;
+		value += ret;
+	}
+	value /= nr_passes;
+
+	return value;
+}
+
+static struct n810bm_adc_calib * n810bm_get_adc_calib(struct n810bm *bm,
+						enum n810bm_pmm_adc_id id)
+{
+	unsigned int index = 0;
+	struct n810bm_adc_calib *cal;
+
+	if (id != N810BM_PMM_ADC_0xFE)
+		index = (unsigned int)id + 1;
+	if (index >= ARRAY_SIZE(bm->calib.adc))
+		return NULL;
+
+	cal = &bm->calib.adc[index];
+	WARN_ON(cal->id && cal->id != id);
+
+	return cal;
+}
+
+static int pmm_record_get(struct n810bm *bm,
+			  const struct firmware *pmm_block,
+			  void *buffer, size_t length,
+			  unsigned int group, unsigned int element, unsigned int offset)
+{
+	const u8 *pmm_area = pmm_block->data;
+	u8 active_group_mask;
+
+	if (pmm_block->size != N810BM_PMM_BLOCK_SIZE)
+		return -EINVAL;
+	if (group >= N810BM_PMM_BLOCK_SIZE / N810BM_PMM_GROUP_SIZE)
+		return -EINVAL;
+	if (element >= N810BM_PMM_GROUP_SIZE / N810BM_PMM_ELEM_SIZE)
+		return -EINVAL;
+	if (offset >= N810BM_PMM_ELEM_SIZE || length > N810BM_PMM_ELEM_SIZE ||
+	    length + offset > N810BM_PMM_ELEM_SIZE)
+		return -EINVAL;
+
+	active_group_mask = pmm_area[16];
+	if (!(active_group_mask & (1 << group))) {
+		dev_dbg(&bm->pdev->dev, "pwm_record_get: Requested group %u, "
+			"but group is not active", group);
+		return -ENOENT;
+	}
+
+	memcpy(buffer,
+	       pmm_area + group * N810BM_PMM_GROUP_SIZE
+			+ element * N810BM_PMM_ELEM_SIZE
+			+ offset,
+	       length);
+
+	return 0;
+}
+
+/* PMM block group 1 element */
+struct group1_element {
+	u8 id;
+	u8 flags;
+	u8 adc_groupnr;
+	u8 _padding;
+	__le32 field1;
+	__le32 field2;
+} __packed;
+
+static int extract_group1_elem(struct n810bm *bm,
+			       const struct firmware *pmm_block,
+			       const enum n810bm_pmm_adc_id *pmm_adc_ids, size_t nr_pmm_adc_ids,
+			       u32 field1_mask, u32 field2_mask)
+{
+	struct group1_element elem;
+	int err;
+	unsigned int i, element_nr;
+	struct n810bm_adc_calib *adc_calib;
+
+	for (i = 0; i < nr_pmm_adc_ids; i++) {
+		element_nr = (unsigned int)(pmm_adc_ids[i]) + 3;
+
+		err = pmm_record_get(bm, pmm_block, &elem, sizeof(elem),
+				     1, element_nr, 0);
+		if (err)
+			continue;
+		adc_calib = n810bm_get_adc_calib(bm, elem.id);
+		if (!adc_calib) {
+			dev_err(&bm->pdev->dev, "extract_group1_elem: "
+				"Could not get calib element for 0x%02X",
+				elem.id);
+			return -EINVAL;
+		}
+
+		if (adc_calib->flags == elem.flags) {
+			adc_calib->field1 = le32_to_cpu(elem.field1) & field1_mask;
+			adc_calib->field2 = le32_to_cpu(elem.field2) & field2_mask;
+		} else {
+			dev_dbg(&bm->pdev->dev, "extract_group1_elem: "
+				"Not extracting fields due to flags mismatch: "
+				"0x%02X vs 0x%02X",
+				adc_calib->flags, elem.flags);
+		}
+	}
+
+	return 0;
+}
+
+static int n810bm_parse_pmm_group1(struct n810bm *bm,
+				   const struct firmware *pmm_block)
+{
+	struct n810bm_adc_calib *adc_calib;
+	struct group1_element elem;
+	int err;
+
+	static const enum n810bm_pmm_adc_id pmm_adc_ids_1[] = {
+		N810BM_PMM_ADC_BATVOLT,
+		N810BM_PMM_ADC_CHGVOLT,
+		N810BM_PMM_ADC_BKUPVOLT,
+		N810BM_PMM_ADC_BATCURR,
+	};
+	static const enum n810bm_pmm_adc_id pmm_adc_ids_2[] = {
+		N810BM_PMM_ADC_BSI,
+	};
+	static const enum n810bm_pmm_adc_id pmm_adc_ids_3[] = {
+		N810BM_PMM_ADC_BATTEMP,
+	};
+
+	/* Parse element 2 */
+	err = pmm_record_get(bm, pmm_block, &elem, sizeof(elem),
+			     1, 2, 0);
+	if (err) {
+		dev_err(&bm->pdev->dev,
+			"PMM: Failed to get group 1 / element 2");
+		return err;
+	}
+	if (elem.id == N810BM_PMM_ADC_0xFE && elem.flags == 0x05) {
+		adc_calib = n810bm_get_adc_calib(bm, elem.id);
+		if (!adc_calib) {
+			dev_err(&bm->pdev->dev,
+				"calib extract: Failed to get 0xFE calib");
+			return -EINVAL;
+		}
+		adc_calib->id = elem.id;
+		adc_calib->flags = elem.flags;
+		adc_calib->field1 = le32_to_cpu(elem.field1);
+		adc_calib->field2 = le32_to_cpu(elem.field2);
+	}
+
+	err = extract_group1_elem(bm, pmm_block,
+				  pmm_adc_ids_1, ARRAY_SIZE(pmm_adc_ids_1),
+				  0xFFFFFFFF, 0xFFFFFFFF);
+	if (err)
+		return err;
+	err = extract_group1_elem(bm, pmm_block,
+				  pmm_adc_ids_2, ARRAY_SIZE(pmm_adc_ids_2),
+				  0xFFFFFFFF, 0);
+	if (err)
+		return err;
+	err = extract_group1_elem(bm, pmm_block,
+				  pmm_adc_ids_3, ARRAY_SIZE(pmm_adc_ids_3),
+				  0xFFFFFFFF, 0x0000FFFF);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static int n810bm_parse_pmm_group2(struct n810bm *bm,
+				   const struct firmware *pmm_block)
+{
+	dev_err(&bm->pdev->dev, "TODO: CAL BME PMM group 2 parser not implemented, yet");
+	return -EOPNOTSUPP;
+}
+
+static void n810bm_adc_calib_set_defaults(struct n810bm *bm)
+{
+	struct n810bm_adc_calib *adc_calib;
+	unsigned int i;
+
+	static const struct n810bm_adc_calib defaults[] = {
+		/* ADC group-nr 0 */
+		{
+			.id		= N810BM_PMM_ADC_HEADSET,
+			.flags		= 0x00,
+			.adc_groupnr	= 0,
+		}, {
+			.id		= N810BM_PMM_ADC_HOOKDET,
+			.flags		= 0x00,
+			.adc_groupnr	= 0,
+		}, {
+			.id		= N810BM_PMM_ADC_RFGP,
+			.flags		= 0x00,
+			.adc_groupnr	= 0,
+		}, {
+			.id		= N810BM_PMM_ADC_LIGHTSENS,
+			.flags		= 0x00,
+			.adc_groupnr	= 0,
+		}, {
+			.id		= N810BM_PMM_ADC_WBTX,
+			.flags		= 0x00,
+			.adc_groupnr	= 0,
+		}, {
+			.id		= N810BM_PMM_ADC_RETUTEMP,
+			.flags		= 0x00,
+			.adc_groupnr	= 0,
+		}, {
+			.id		= N810BM_PMM_ADC_GND2,
+			.flags		= 0x00,
+			.adc_groupnr	= 0,
+		},
+		/* ADC group-nr 1 */
+		{
+			.id		= N810BM_PMM_ADC_0xFE,
+			.flags		= 0x05,
+			.adc_groupnr	= 1,
+			.field1		= (u32)-2,
+			.field2		= 13189,
+		}, {
+			.id		= N810BM_PMM_ADC_BATVOLT,
+			.flags		= 0x01,
+			.adc_groupnr	= 1,
+			.field1		= 2527,
+			.field2		= 21373,
+		}, {
+			.id		= N810BM_PMM_ADC_CHGVOLT,
+			.flags		= 0x01,
+			.adc_groupnr	= 1,
+			.field1		= 0,
+			.field2		= 129848,
+		}, {
+			.id		= N810BM_PMM_ADC_BKUPVOLT,
+			.flags		= 0x01,
+			.adc_groupnr	= 1,
+			.field1		= 0,
+			.field2		= 20000,
+		}, {
+			.id		= N810BM_PMM_ADC_BATCURR,
+			.flags		= 0x06,
+			.adc_groupnr	= 1,
+			.field1		= 0,
+			.field2		= 9660,
+		},
+		/* ADC group-nr 2 */
+		{
+			.id		= N810BM_PMM_ADC_BSI,
+			.flags		= 0x02,
+			.adc_groupnr	= 2,
+			.field1		= 1169,
+			.field2		= 0,
+		},
+		/* ADC group-nr 3 */
+		{
+			.id		= N810BM_PMM_ADC_BATTEMP,
+			.flags		= 0x03,
+			.adc_groupnr	= 3,
+			.field1		= 265423000,
+			.field2		= 298,
+		},
+		/* ADC group-nr 4 */
+		{
+			.id		= N810BM_PMM_ADC_LIGHTTEMP,
+			.flags		= 0x04,
+			.adc_groupnr	= 4,
+			.field1		= 19533778,
+			.field2		= 308019670,
+			.field3		= 4700,
+			.field4		= 2500,
+		},
+	};
+
+	/* Clear the array */
+	memset(&bm->calib.adc, 0, sizeof(bm->calib.adc));
+	for (i = 0; i < ARRAY_SIZE(bm->calib.adc); i++)
+		bm->calib.adc[i].flags = 0xFF;
+
+	/* Copy the defaults */
+	for (i = 0; i < ARRAY_SIZE(defaults); i++) {
+		adc_calib = n810bm_get_adc_calib(bm, defaults[i].id);
+		if (WARN_ON(!adc_calib))
+			continue;
+		*adc_calib = defaults[i];
+	}
+}
+
+static int n810bm_parse_pmm_block(struct n810bm *bm,
+				  const struct firmware *pmm_block)
+{
+	u8 byte;
+	int err;
+	unsigned int i, count;
+	struct n810bm_adc_calib *adc_calib;
+
+	/* Initialize to defaults */
+	n810bm_adc_calib_set_defaults(bm);
+
+	/* Parse the PMM data */
+	err = pmm_record_get(bm, pmm_block, &byte, sizeof(byte),
+			     1, 0, 0); /* group 1 / element 0 */
+	err |= (byte != 0x01);
+	err |= pmm_record_get(bm, pmm_block, &byte, sizeof(byte),
+			      1, 1, 0); /* group 1 / element 1 */
+	err |= (byte != 0x01);
+	if (err)
+		err = n810bm_parse_pmm_group2(bm, pmm_block);
+	else
+		err = n810bm_parse_pmm_group1(bm, pmm_block);
+	if (err)
+		return err;
+
+	/* Sanity checks */
+	for (i = 0, count = 0; i < ARRAY_SIZE(bm->calib.adc); i++) {
+		adc_calib = &bm->calib.adc[i];
+		if (adc_calib->flags == 0xFF)
+			continue;
+		switch (adc_calib->id) {
+		case N810BM_PMM_ADC_BATVOLT:
+			if (adc_calib->field1 < 2400 ||
+			    adc_calib->field1 > 2700)
+				goto value_check_fail;
+			if (adc_calib->field2 < 20000 ||
+			    adc_calib->field2 > 23000)
+				goto value_check_fail;
+			count++;
+			break;
+		case N810BM_PMM_ADC_BSI:
+			if (adc_calib->field1 < 1100 ||
+			    adc_calib->field1 > 1300)
+				goto value_check_fail;
+			count++;
+			break;
+		case N810BM_PMM_ADC_BATCURR:
+			if (adc_calib->field2 < 7000 ||
+			    adc_calib->field2 > 12000)
+				goto value_check_fail;
+			count++;
+			break;
+		case N810BM_PMM_ADC_0xFE:
+			if ((s32)adc_calib->field1 > 14 ||
+			    (s32)adc_calib->field1 < -14)
+				goto value_check_fail;
+			if (adc_calib->field2 < 13000 ||
+			    adc_calib->field2 > 13350)
+				goto value_check_fail;
+			count++;
+			break;
+		case N810BM_PMM_ADC_CHGVOLT:
+		case N810BM_PMM_ADC_BATTEMP:
+		case N810BM_PMM_ADC_BKUPVOLT:
+			count++;
+			break;
+		case N810BM_PMM_ADC_GND2:
+		case N810BM_PMM_ADC_HOOKDET:
+		case N810BM_PMM_ADC_LIGHTSENS:
+		case N810BM_PMM_ADC_HEADSET:
+		case N810BM_PMM_ADC_LIGHTTEMP:
+		case N810BM_PMM_ADC_RFGP:
+		case N810BM_PMM_ADC_WBTX:
+		case N810BM_PMM_ADC_RETUTEMP:
+			break;
+		}
+		dev_dbg(&bm->pdev->dev,
+			"ADC 0x%02X calib: 0x%02X 0x%02X 0x%08X 0x%08X 0x%04X 0x%04X",
+			adc_calib->id, adc_calib->flags, adc_calib->adc_groupnr,
+			adc_calib->field1, adc_calib->field2,
+			adc_calib->field3, adc_calib->field4);
+	}
+	if (count != 7) {
+		dev_err(&bm->pdev->dev, "PMM sanity check: Did not find "
+			"all required values (count=%u)", count);
+		goto check_fail;
+	}
+
+	return 0;
+
+value_check_fail:
+	dev_err(&bm->pdev->dev, "PMM image sanity check failed "
+		"(id=%02X, field1=%08X, field2=%08X)",
+		adc_calib->id, adc_calib->field1, adc_calib->field2);
+check_fail:
+	return -EILSEQ;
+}
+
+/* Set the current measure timer that triggers on Tahvo IRQ 7
+ * An interval of zero disables the timer. */
+static void n810bm_set_current_measure_timer(struct n810bm *bm,
+					     u16 millisec_interval)
+{
+	u16 value = millisec_interval;
+
+	if (value <= 0xF905) {
+		value = ((u64)0x10624DD3 * (u64)(value + 0xF9)) >> 32;
+		value /= 16;
+	} else
+		value = 0xFF;
+
+	tahvo_write(bm, TAHVO_REG_BATCURRTIMER, value & 0xFF);
+
+	tahvo_set(bm, TAHVO_REG_CHGCTL,
+		  TAHVO_REG_CHGCTL_CURTIMRST);
+	tahvo_clear(bm, TAHVO_REG_CHGCTL,
+		    TAHVO_REG_CHGCTL_CURTIMRST);
+
+	if (millisec_interval) {
+		if (!bm->tahvo_irq_enabled) {
+			bm->tahvo_irq_enabled = 1;
+			enable_irq(bm->tahvo_irq);
+		}
+	} else {
+		if (bm->tahvo_irq_enabled) {
+			bm->tahvo_irq_enabled = 0;
+			disable_irq_nosync(bm->tahvo_irq);
+		}
+	}
+
+	//TODO also do a software timer for safety.
+}
+
+static void n810bm_enable_current_measure(struct n810bm *bm)
+{
+	WARN_ON(bm->current_measure_enabled < 0);
+	if (!bm->current_measure_enabled) {
+		/* Enable the current measurement circuitry */
+		tahvo_set(bm, TAHVO_REG_CHGCTL,
+			  TAHVO_REG_CHGCTL_CURMEAS);
+		dev_dbg(&bm->pdev->dev,
+			"Current measurement circuitry enabled");
+	}
+	bm->current_measure_enabled++;
+}
+
+static void n810bm_disable_current_measure(struct n810bm *bm)
+{
+	bm->current_measure_enabled--;
+	WARN_ON(bm->current_measure_enabled < 0);
+	if (!bm->current_measure_enabled) {
+		/* Disable the current measurement circuitry */
+		tahvo_clear(bm, TAHVO_REG_CHGCTL,
+			    TAHVO_REG_CHGCTL_CURMEAS);
+		dev_dbg(&bm->pdev->dev,
+			"Current measurement circuitry disabled");
+	}
+}
+
+/* Measure the actual battery current. Returns a signed value in mA.
+ * Does only work, if current measurement was enabled. */
+static int n810bm_measure_batt_current(struct n810bm *bm)
+{
+	u16 retval;
+	int adc = 0, ma, i;
+
+	if (WARN_ON(bm->current_measure_enabled <= 0))
+		return 0;
+	for (i = 0; i < 3; i++) {
+		retval = tahvo_read(bm, TAHVO_REG_BATCURR);
+		adc += (s16)retval; /* Value is signed */
+	}
+	adc /= 3;
+
+	//TODO convert to mA
+	ma = adc;
+
+	return ma;
+}
+
+/* Requires bm->mutex locked */
+static int n810bm_measure_batt_current_async(struct n810bm *bm)
+{
+	int ma;
+	bool charging = lipocharge_is_charging(&bm->charger);
+
+	n810bm_enable_current_measure(bm);
+	if (!charging)
+		WARN_ON(bm->active_current_pwm != 0);
+	tahvo_maskset(bm, TAHVO_REG_CHGCTL,
+		      TAHVO_REG_CHGCTL_EN |
+		      TAHVO_REG_CHGCTL_PWMOVR |
+		      TAHVO_REG_CHGCTL_PWMOVRZERO,
+		      TAHVO_REG_CHGCTL_EN |
+		      TAHVO_REG_CHGCTL_PWMOVR |
+		      (charging ? 0 : TAHVO_REG_CHGCTL_PWMOVRZERO));
+	ma = n810bm_measure_batt_current(bm);
+	tahvo_maskset(bm, TAHVO_REG_CHGCTL,
+		      TAHVO_REG_CHGCTL_EN |
+		      TAHVO_REG_CHGCTL_PWMOVR |
+		      TAHVO_REG_CHGCTL_PWMOVRZERO,
+		      (charging ? TAHVO_REG_CHGCTL_EN : 0));
+	n810bm_disable_current_measure(bm);
+
+	return ma;
+}
+
+static int adc_sanity_check(struct n810bm *bm, unsigned int channel)
+{
+	int value;
+
+	value = retu_read_adc(&n810bm_retu_device->dev, channel);
+	if (value < 0) {
+		dev_err(&bm->pdev->dev, "Failed to read GND ADC channel %u",
+			channel);
+		return -EIO;
+	}
+	dev_dbg(&bm->pdev->dev,
+		"GND ADC channel %u sanity check got value: %d",
+		channel, value);
+	if (value > 5) {
+		n810bm_emergency(bm, "GND ADC sanity check failed");
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int n810bm_check_adc_sanity(struct n810bm *bm)
+{
+	int err;
+
+	/* Discard one conversion */
+	retu_write(bm, RETU_REG_ADCSCR, 0);
+	retu_read_adc(&n810bm_retu_device->dev, RETU_ADC_GND2);
+
+	err = adc_sanity_check(bm, RETU_ADC_GND2);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+/* Measure the battery voltage. Returns the value in mV (or negative value on error). */
+static int n810bm_measure_batt_voltage(struct n810bm *bm)
+{
+	int adc;
+	unsigned int mv;
+	const unsigned int scale = 1000;
+
+	adc = retu_adc_average(bm, RETU_ADC_BATTVOLT, 5);
+	if (adc < 0)
+		return adc;
+	if (adc <= 0x37)
+		return 2800;
+	mv = 2800 + ((adc - 0x37) * (((4200 - 2800) * scale) / (0x236 - 0x37))) / scale;
+
+	//TODO compensate for power consumption
+	//TODO honor calibration values
+
+	return mv;
+}
+
+/* Measure the charger voltage. Returns the value in mV (or negative value on error). */
+static int n810bm_measure_charger_voltage(struct n810bm *bm)
+{
+	int adc;
+	unsigned int mv;
+
+	adc = retu_adc_average(bm, RETU_ADC_CHGVOLT, 5);
+	if (adc < 0)
+		return adc;
+	//TODO convert to mV
+	mv = adc;
+
+	return mv;
+}
+
+/* Measure backup battery voltage. Returns the value in mV (or negative value on error). */
+static int n810bm_measure_backup_batt_voltage(struct n810bm *bm)
+{
+	int adc;
+	unsigned int mv;
+
+	adc = retu_adc_average(bm, RETU_ADC_BKUPVOLT, 3);
+	if (adc < 0)
+		return adc;
+	//TODO convert to mV
+	mv = adc;
+
+	return mv;
+}
+
+/* Measure the battery temperature. Returns the value in K (or negative value on error). */
+static int n810bm_measure_batt_temp(struct n810bm *bm)
+{
+	int adc;
+	unsigned int k;
+
+	adc = retu_adc_average(bm, RETU_ADC_BATTEMP, 3);
+	if (adc < 0)
+		return adc;
+	//TODO convert to K
+	k = adc;
+
+	return k;
+}
+
+/* Read the battery capacity via BSI pin. */
+static enum n810bm_capacity n810bm_read_batt_capacity(struct n810bm *bm)
+{
+	int adc;
+	const unsigned int hyst = 20;
+
+	adc = retu_adc_average(bm, RETU_ADC_BSI, 5);
+	if (adc < 0) {
+		dev_err(&bm->pdev->dev, "Failed to read BSI ADC");
+		return N810BM_CAP_UNKNOWN;
+	}
+
+	if (adc >= 0x3B5 - hyst && adc <= 0x3B5 + hyst)
+		return N810BM_CAP_1500MAH;
+
+	dev_err(&bm->pdev->dev, "Capacity indicator 0x%X unknown", adc);
+
+	return N810BM_CAP_UNKNOWN;
+}
+
+/* Convert a battery voltage (in mV) to percentage. */
+static unsigned int n810bm_mvolt2percent(unsigned int mv)
+{
+	const unsigned int minv = 3700;
+	const unsigned int maxv = 4150;
+	unsigned int percent;
+
+	mv = clamp(mv, minv, maxv);
+	percent = (mv - minv) * 100 / (maxv - minv);
+
+	return percent;
+}
+
+static void n810bm_start_charge(struct n810bm *bm)
+{
+	int err;
+
+	WARN_ON(!bm->battery_present);
+	WARN_ON(!bm->charger_present);
+
+	/* Set PWM to zero */
+	bm->active_current_pwm = 0;
+	tahvo_write(bm, TAHVO_REG_CHGCURR, bm->active_current_pwm);
+
+	/* Charge global enable */
+	tahvo_maskset(bm, TAHVO_REG_CHGCTL,
+		      TAHVO_REG_CHGCTL_EN |
+		      TAHVO_REG_CHGCTL_PWMOVR |
+		      TAHVO_REG_CHGCTL_PWMOVRZERO,
+		      TAHVO_REG_CHGCTL_EN);
+
+	WARN_ON((int)bm->capacity <= 0);
+	bm->charger.capacity = bm->capacity;
+	err = lipocharge_start(&bm->charger);
+	WARN_ON(err);
+
+	/* Initialize current measurement circuitry */
+	n810bm_enable_current_measure(bm);
+	n810bm_set_current_measure_timer(bm, 250);
+
+	dev_info(&bm->pdev->dev, "Charging battery");
+	n810bm_notify_charger_state(bm);
+	n810bm_notify_charger_pwm(bm);
+}
+
+static void n810bm_stop_charge(struct n810bm *bm)
+{
+	if (lipocharge_is_charging(&bm->charger)) {
+		n810bm_set_current_measure_timer(bm, 0);
+		n810bm_disable_current_measure(bm);
+	}
+	lipocharge_stop(&bm->charger);
+
+	/* Set PWM to zero */
+	bm->active_current_pwm = 0;
+	tahvo_write(bm, TAHVO_REG_CHGCURR, bm->active_current_pwm);
+
+	/* Charge global disable */
+	tahvo_maskset(bm, TAHVO_REG_CHGCTL,
+		      TAHVO_REG_CHGCTL_EN |
+		      TAHVO_REG_CHGCTL_PWMOVR |
+		      TAHVO_REG_CHGCTL_PWMOVRZERO,
+		      0);
+
+	dev_info(&bm->pdev->dev, "Not charging battery");
+	n810bm_notify_charger_state(bm);
+	n810bm_notify_charger_pwm(bm);
+}
+
+/* Periodic check */
+static void n810bm_periodic_check_work(struct work_struct *work)
+{
+	struct n810bm *bm = container_of(to_delayed_work(work),
+					 struct n810bm, periodic_check_work);
+	u16 status;
+	bool battery_was_present, charger_was_present;
+	int mv;
+
+	mutex_lock(&bm->mutex);
+
+	status = retu_read(bm, RETU_REG_STATUS);
+	battery_was_present = bm->battery_present;
+	charger_was_present = bm->charger_present;
+	bm->battery_present = !!(status & RETU_REG_STATUS_BATAVAIL);
+	bm->charger_present = !!(status & RETU_REG_STATUS_CHGPLUG);
+
+	if (bm->battery_present != battery_was_present) {
+		/* Battery state changed */
+		if (bm->battery_present) {
+			bm->capacity = n810bm_read_batt_capacity(bm);
+			if (bm->capacity == N810BM_CAP_UNKNOWN) {
+				dev_err(&bm->pdev->dev, "Unknown battery detected");
+			} else {
+				dev_info(&bm->pdev->dev, "Detected %u mAh battery",
+					 (unsigned int)bm->capacity);
+			}
+		} else {
+			bm->capacity = N810BM_CAP_NONE;
+			dev_info(&bm->pdev->dev, "The main battery was removed");
+			//TODO disable charging
+		}
+	}
+
+	if (bm->charger_present != charger_was_present) {
+		/* Charger state changed */
+		dev_info(&bm->pdev->dev, "The charger was %s",
+			 bm->charger_present ? "plugged in" : "removed");
+		n810bm_notify_charger_present(bm);
+	}
+
+	if ((bm->battery_present && !bm->charger_present) ||
+	    !n810bm_known_battery_present(bm)){
+		/* We're draining the battery */
+		mv = n810bm_measure_batt_voltage(bm);
+		if (mv < 0) {
+			n810bm_emergency(bm,
+				"check: Failed to measure voltage");
+		}
+		if (mv < N810BM_MIN_VOLTAGE_THRES) {
+			n810bm_emergency(bm,
+				"check: Minimum voltage threshold reached");
+		}
+	}
+
+	if (bm->charger_present && n810bm_known_battery_present(bm)) {
+		/* Known battery and charger are connected */
+		if (bm->charger_enabled) {
+			/* Charger is enabled */
+			if (!lipocharge_is_charging(&bm->charger)) {
+				//TODO start charging, if battery is below some threshold
+				n810bm_start_charge(bm);
+			}
+		}
+	}
+
+	if (lipocharge_is_charging(&bm->charger) && !bm->charger_present) {
+		/* Charger was unplugged. */
+		n810bm_stop_charge(bm);
+	}
+
+	mutex_unlock(&bm->mutex);
+	schedule_delayed_work(&bm->periodic_check_work,
+			      round_jiffies_relative(N810BM_CHECK_INTERVAL));
+}
+
+/*XXX
+static void n810bm_adc_irq_handler(unsigned long data)
+{
+	struct n810bm *bm = (struct n810bm *)data;
+
+	retu_ack_irq(RETU_INT_ADCS);
+	//TODO
+dev_info(&bm->pdev->dev, "ADC interrupt triggered\n");
+}
+*/
+
+static irqreturn_t n810bm_tahvo_current_measure_irq_handler(int irq, void *data)
+{
+	struct n810bm *bm = data;
+	int res, ma, mv, temp;
+
+	mutex_lock(&bm->mutex);
+	if (!lipocharge_is_charging(&bm->charger))
+		goto out_unlock;
+
+	tahvo_maskset(bm, TAHVO_REG_CHGCTL,
+		      TAHVO_REG_CHGCTL_PWMOVR |
+		      TAHVO_REG_CHGCTL_PWMOVRZERO,
+		      TAHVO_REG_CHGCTL_PWMOVR);
+	ma = n810bm_measure_batt_current(bm);
+	tahvo_maskset(bm, TAHVO_REG_CHGCTL,
+		      TAHVO_REG_CHGCTL_PWMOVR |
+		      TAHVO_REG_CHGCTL_PWMOVRZERO,
+		      TAHVO_REG_CHGCTL_PWMOVR |
+		      TAHVO_REG_CHGCTL_PWMOVRZERO);
+	msleep(10);
+	mv = n810bm_measure_batt_voltage(bm);
+	tahvo_maskset(bm, TAHVO_REG_CHGCTL,
+		      TAHVO_REG_CHGCTL_PWMOVR |
+		      TAHVO_REG_CHGCTL_PWMOVRZERO,
+		      0);
+	temp = n810bm_measure_batt_temp(bm);
+	if (WARN_ON(mv < 0))
+		goto out_unlock;
+	if (WARN_ON(temp < 0))
+		goto out_unlock;
+
+	if (bm->verbose_charge_log) {
+		dev_info(&bm->pdev->dev,
+			 "Battery charge state: %d mV, %d mA (%s)",
+			 mv, ma,
+			 (ma <= 0) ? "discharging" : "charging");
+	}
+	res = lipocharge_update_state(&bm->charger, mv, ma, temp);
+	if (res) {
+		if (res > 0)
+			dev_info(&bm->pdev->dev, "Battery fully charged");
+		n810bm_stop_charge(bm);
+	}
+out_unlock:
+	mutex_unlock(&bm->mutex);
+
+	return IRQ_HANDLED;
+}
+
+#define DEFINE_ATTR_NOTIFY(attr_name)						\
+	void n810bm_notify_##attr_name(struct n810bm *bm)			\
+	{									\
+		set_bit(N810BM_NOTIFY_##attr_name, &bm->notify_flags);		\
+		wmb();								\
+		schedule_work(&bm->notify_work);				\
+	}
+
+#define DEFINE_SHOW_INT_FUNC(name, member)					\
+	static ssize_t n810bm_attr_##name##_show(struct device *dev,		\
+						 struct device_attribute *attr,	\
+						 char *buf)			\
+	{									\
+		struct n810bm *bm = device_to_n810bm(dev);			\
+		ssize_t count;							\
+										\
+		mutex_lock(&bm->mutex);						\
+		count = snprintf(buf, PAGE_SIZE, "%d\n", (int)(bm->member));	\
+		mutex_unlock(&bm->mutex);					\
+										\
+		return count;							\
+	}
+
+#define DEFINE_STORE_INT_FUNC(name, member)					\
+	static ssize_t n810bm_attr_##name##_store(struct device *dev,		\
+						  struct device_attribute *attr,\
+						  const char *buf, size_t count)\
+	{									\
+		struct n810bm *bm = device_to_n810bm(dev);			\
+		long val;							\
+		int err;							\
+										\
+		mutex_lock(&bm->mutex);						\
+		err = strict_strtol(buf, 0, &val);				\
+		if (!err)							\
+			bm->member = (typeof(bm->member))val;			\
+		mutex_unlock(&bm->mutex);					\
+										\
+		return err ? err : count;					\
+	}
+
+#define DEFINE_ATTR_SHOW_INT(name, member)					\
+	DEFINE_SHOW_INT_FUNC(name, member)					\
+	static DEVICE_ATTR(name, S_IRUGO,					\
+			   n810bm_attr_##name##_show, NULL);
+
+#define DEFINE_ATTR_SHOW_STORE_INT(name, member)				\
+	DEFINE_SHOW_INT_FUNC(name, member)					\
+	DEFINE_STORE_INT_FUNC(name, member)					\
+	static DEVICE_ATTR(name, S_IRUGO | S_IWUSR,				\
+			   n810bm_attr_##name##_show,				\
+			   n810bm_attr_##name##_store);
+
+DEFINE_ATTR_SHOW_INT(battery_present, battery_present);
+DEFINE_ATTR_SHOW_INT(charger_present, charger_present);
+static DEFINE_ATTR_NOTIFY(charger_present);
+DEFINE_ATTR_SHOW_INT(charger_state, charger.state);
+static DEFINE_ATTR_NOTIFY(charger_state);
+DEFINE_ATTR_SHOW_INT(charger_pwm, active_current_pwm);
+static DEFINE_ATTR_NOTIFY(charger_pwm);
+DEFINE_ATTR_SHOW_STORE_INT(charger_enable, charger_enabled);
+DEFINE_ATTR_SHOW_STORE_INT(charger_verbose, verbose_charge_log);
+
+static ssize_t n810bm_attr_battery_level_show(struct device *dev,
+					      struct device_attribute *attr,
+					      char *buf)
+{
+	struct n810bm *bm = device_to_n810bm(dev);
+	ssize_t count = -ENODEV;
+	int millivolt;
+
+	mutex_lock(&bm->mutex);
+	if (!bm->battery_present || lipocharge_is_charging(&bm->charger))
+		millivolt = 0;
+	else
+		millivolt = n810bm_measure_batt_voltage(bm);
+	if (millivolt >= 0) {
+		count = snprintf(buf, PAGE_SIZE, "%u\n",
+				 n810bm_mvolt2percent(millivolt));
+	}
+	mutex_unlock(&bm->mutex);
+
+	return count;
+}
+static DEVICE_ATTR(battery_level, S_IRUGO,
+		   n810bm_attr_battery_level_show, NULL);
+
+static ssize_t n810bm_attr_battery_capacity_show(struct device *dev,
+						 struct device_attribute *attr,
+						 char *buf)
+{
+	struct n810bm *bm = device_to_n810bm(dev);
+	ssize_t count;
+	int capacity = 0;
+
+	mutex_lock(&bm->mutex);
+	if (n810bm_known_battery_present(bm))
+		capacity = (int)bm->capacity;
+	count = snprintf(buf, PAGE_SIZE, "%d\n", capacity);
+	mutex_unlock(&bm->mutex);
+
+	return count;
+}
+static DEVICE_ATTR(battery_capacity, S_IRUGO,
+		   n810bm_attr_battery_capacity_show, NULL);
+
+static ssize_t n810bm_attr_battery_temp_show(struct device *dev,
+					     struct device_attribute *attr,
+					     char *buf)
+{
+	struct n810bm *bm = device_to_n810bm(dev);
+	ssize_t count = -ENODEV;
+	int k;
+
+	mutex_lock(&bm->mutex);
+	k = n810bm_measure_batt_temp(bm);
+	if (k >= 0)
+		count = snprintf(buf, PAGE_SIZE, "%d\n", k);
+	mutex_unlock(&bm->mutex);
+
+	return count;
+}
+static DEVICE_ATTR(battery_temp, S_IRUGO,
+		   n810bm_attr_battery_temp_show, NULL);
+
+static ssize_t n810bm_attr_charger_voltage_show(struct device *dev,
+						struct device_attribute *attr,
+						char *buf)
+{
+	struct n810bm *bm = device_to_n810bm(dev);
+	ssize_t count = -ENODEV;
+	int mv = 0;
+
+	mutex_lock(&bm->mutex);
+	if (bm->charger_present)
+		mv = n810bm_measure_charger_voltage(bm);
+	if (mv >= 0)
+		count = snprintf(buf, PAGE_SIZE, "%d\n", mv);
+	mutex_unlock(&bm->mutex);
+
+	return count;
+}
+static DEVICE_ATTR(charger_voltage, S_IRUGO,
+		   n810bm_attr_charger_voltage_show, NULL);
+
+static ssize_t n810bm_attr_backup_battery_voltage_show(struct device *dev,
+						       struct device_attribute *attr,
+						       char *buf)
+{
+	struct n810bm *bm = device_to_n810bm(dev);
+	ssize_t count = -ENODEV;
+	int mv;
+
+	mutex_lock(&bm->mutex);
+	mv = n810bm_measure_backup_batt_voltage(bm);
+	if (mv >= 0)
+		count = snprintf(buf, PAGE_SIZE, "%d\n", mv);
+	mutex_unlock(&bm->mutex);
+
+	return count;
+}
+static DEVICE_ATTR(backup_battery_voltage, S_IRUGO,
+		   n810bm_attr_backup_battery_voltage_show, NULL);
+
+static ssize_t n810bm_attr_battery_current_show(struct device *dev,
+						struct device_attribute *attr,
+						char *buf)
+{
+	struct n810bm *bm = device_to_n810bm(dev);
+	ssize_t count = -ENODEV;
+	int ma = 0;
+
+	mutex_lock(&bm->mutex);
+	if (bm->battery_present)
+		ma = n810bm_measure_batt_current_async(bm);
+	count = snprintf(buf, PAGE_SIZE, "%d\n", ma);
+	mutex_unlock(&bm->mutex);
+
+	return count;
+}
+static DEVICE_ATTR(battery_current, S_IRUGO,
+		   n810bm_attr_battery_current_show, NULL);
+
+static const struct device_attribute *n810bm_attrs[] = {
+	&dev_attr_battery_present,
+	&dev_attr_battery_level,
+	&dev_attr_battery_current,
+	&dev_attr_battery_capacity,
+	&dev_attr_battery_temp,
+	&dev_attr_backup_battery_voltage,
+	&dev_attr_charger_present,
+	&dev_attr_charger_state,
+	&dev_attr_charger_verbose,
+	&dev_attr_charger_voltage,
+	&dev_attr_charger_enable,
+	&dev_attr_charger_pwm,
+};
+
+static void n810bm_notify_work(struct work_struct *work)
+{
+	struct n810bm *bm = container_of(work, struct n810bm, notify_work);
+	unsigned long notify_flags;
+
+	notify_flags = xchg(&bm->notify_flags, 0);
+	mb();
+
+#define do_notify(attr_name)						\
+	do {								\
+		if (notify_flags & (1 << N810BM_NOTIFY_##attr_name)) {	\
+			sysfs_notify(&bm->pdev->dev.kobj, NULL,		\
+				     dev_attr_##attr_name.attr.name);	\
+		}							\
+	} while (0)
+
+	do_notify(charger_present);
+	do_notify(charger_state);
+	do_notify(charger_pwm);
+}
+
+static int n810bm_charger_set_current_pwm(struct lipocharge *c,
+					  unsigned int duty_cycle)
+{
+	struct n810bm *bm = container_of(c, struct n810bm, charger);
+	int err = -EINVAL;
+
+	WARN_ON(!mutex_is_locked(&bm->mutex));
+	if (WARN_ON(duty_cycle > 0xFF))
+		goto out;
+	if (WARN_ON(!bm->charger_enabled))
+		goto out;
+	if (WARN_ON(!bm->battery_present || !bm->charger_present))
+		goto out;
+
+	if (duty_cycle != bm->active_current_pwm) {
+		bm->active_current_pwm = duty_cycle;
+		tahvo_write(bm, TAHVO_REG_CHGCURR, duty_cycle);
+		n810bm_notify_charger_pwm(bm);
+	}
+
+	err = 0;
+out:
+
+	return err;
+}
+
+static void n810bm_charger_emergency(struct lipocharge *c)
+{
+	struct n810bm *bm = container_of(c, struct n810bm, charger);
+
+	n810bm_emergency(bm, "Battery charger fault");
+}
+
+static void n810bm_hw_exit(struct n810bm *bm)
+{
+	n810bm_stop_charge(bm);
+	retu_write(bm, RETU_REG_ADCSCR, 0);
+}
+
+static int n810bm_hw_init(struct n810bm *bm)
+{
+	int err;
+
+	err = n810bm_check_adc_sanity(bm);
+	if (err)
+		return err;
+
+	n810bm_stop_charge(bm);
+
+	return 0;
+}
+
+static void n810bm_cancel_and_flush_work(struct n810bm *bm)
+{
+	cancel_delayed_work_sync(&bm->periodic_check_work);
+	cancel_work_sync(&bm->notify_work);
+	flush_scheduled_work();
+}
+
+static int n810bm_device_init(struct n810bm *bm)
+{
+	int attr_index;
+	int err;
+
+	bm->charger.rate = LIPORATE_p6C;
+	bm->charger.top_voltage = 4100;
+	bm->charger.duty_cycle_max = 0xFF;
+	bm->charger.set_current_pwm = n810bm_charger_set_current_pwm;
+	bm->charger.emergency = n810bm_charger_emergency;
+	lipocharge_init(&bm->charger, &bm->pdev->dev);
+
+	err = n810bm_hw_init(bm);
+	if (err)
+		goto error;
+	for (attr_index = 0; attr_index < ARRAY_SIZE(n810bm_attrs); attr_index++) {
+		err = device_create_file(&bm->pdev->dev, n810bm_attrs[attr_index]);
+		if (err)
+			goto err_unwind_attrs;
+	}
+/*XXX
+	err = retu_request_irq(RETU_INT_ADCS,
+			       n810bm_adc_irq_handler,
+			       (unsigned long)bm, "n810bm");
+	if (err)
+		goto err_unwind_attrs;
+*/
+	bm->tahvo_irq = platform_get_irq(n810bm_tahvo_device, 0);
+	err = request_threaded_irq(bm->tahvo_irq, NULL,
+				   n810bm_tahvo_current_measure_irq_handler,
+				   IRQF_ONESHOT, "tahvo-n810bm", bm);
+	if (err)
+		goto err_free_retu_irq;
+	disable_irq_nosync(bm->tahvo_irq);
+	bm->tahvo_irq_enabled = 0;
+
+	schedule_delayed_work(&bm->periodic_check_work,
+			      round_jiffies_relative(N810BM_CHECK_INTERVAL));
+
+	bm->initialized = 1;
+	dev_info(&bm->pdev->dev, "Battery management initialized");
+
+	return 0;
+
+err_free_retu_irq:
+//XXX	retu_free_irq(RETU_INT_ADCS);
+err_unwind_attrs:
+	for (attr_index--; attr_index >= 0; attr_index--)
+		device_remove_file(&bm->pdev->dev, n810bm_attrs[attr_index]);
+/*err_exit:*/
+	n810bm_hw_exit(bm);
+error:
+	n810bm_cancel_and_flush_work(bm);
+
+	return err;
+}
+
+static void n810bm_device_exit(struct n810bm *bm)
+{
+	int i;
+
+	if (!bm->initialized)
+		return;
+
+	lipocharge_exit(&bm->charger);
+	free_irq(bm->tahvo_irq, bm);
+//XXX	retu_free_irq(RETU_INT_ADCS);
+	for (i = 0; i < ARRAY_SIZE(n810bm_attrs); i++)
+		device_remove_file(&bm->pdev->dev, n810bm_attrs[i]);
+
+	n810bm_cancel_and_flush_work(bm);
+
+	n810bm_hw_exit(bm);
+
+	bm->initialized = 0;
+}
+
+static void n810bm_pmm_block_found(const struct firmware *fw, void *context)
+{
+	struct n810bm *bm = context;
+	int err;
+
+	if (!fw) {
+		dev_err(&bm->pdev->dev,
+			"CAL PMM block image file not found");
+		goto err_release;
+	}
+	if (fw->size != N810BM_PMM_BLOCK_SIZE ||
+	    memcmp(fw->data, "BME-PMM-BLOCK01", 15) != 0) {
+		dev_err(&bm->pdev->dev,
+			"CAL PMM block image file has an invalid format");
+		goto err_release;
+	}
+
+	err = n810bm_parse_pmm_block(bm, fw);
+	if (err)
+		goto err_release;
+	release_firmware(fw);
+
+	err = n810bm_device_init(bm);
+	if (err) {
+		dev_err(&bm->pdev->dev,
+			"Failed to initialized battery management (%d)", err);
+		goto error;
+	}
+
+	return;
+err_release:
+	release_firmware(fw);
+error:
+	return;
+}
+
+static int __devinit n810bm_probe(void)
+{
+	struct n810bm *bm;
+	int err;
+
+	if (!n810bm_retu_device || !n810bm_tahvo_device)
+		return 0;
+
+	bm = kzalloc(sizeof(*bm), GFP_KERNEL);
+	if (!bm)
+		return -ENOMEM;
+	bm->pdev = n810bm_retu_device;
+	platform_set_drvdata(n810bm_retu_device, bm);
+	platform_set_drvdata(n810bm_tahvo_device, bm);
+	mutex_init(&bm->mutex);
+	INIT_DELAYED_WORK(&bm->periodic_check_work, n810bm_periodic_check_work);
+	INIT_WORK(&bm->notify_work, n810bm_notify_work);
+
+	dev_info(&bm->pdev->dev, "Requesting CAL BME PMM block firmware file "
+		 N810BM_PMM_BLOCK_FILENAME);
+	err = request_firmware_nowait(THIS_MODULE, 1,
+				      N810BM_PMM_BLOCK_FILENAME,
+				      &bm->pdev->dev, GFP_KERNEL,
+				      bm, n810bm_pmm_block_found);
+	if (err) {
+		dev_err(&bm->pdev->dev,
+			"Failed to request CAL PMM block image file (%d)", err);
+		goto err_free;
+	}
+
+	return 0;
+
+err_free:
+	kfree(bm);
+
+	return err;
+}
+
+static void __devexit n810bm_remove(void)
+{
+	struct n810bm *bm;
+
+	if (!n810bm_retu_device || !n810bm_tahvo_device)
+		return;
+	bm = platform_get_drvdata(n810bm_retu_device);
+
+	n810bm_device_exit(bm);
+
+	kfree(bm);
+	platform_set_drvdata(n810bm_retu_device, NULL);
+	platform_set_drvdata(n810bm_tahvo_device, NULL);
+}
+
+static int __devinit n810bm_retu_probe(struct platform_device *pdev)
+{
+	n810bm_retu_device = pdev;
+	return n810bm_probe();
+}
+
+static int __devexit n810bm_retu_remove(struct platform_device *pdev)
+{
+	n810bm_remove();
+	n810bm_retu_device = NULL;
+	return 0;
+}
+
+static int __devinit n810bm_tahvo_probe(struct platform_device *pdev)
+{
+	n810bm_tahvo_device = pdev;
+	return n810bm_probe();
+}
+
+static int __devexit n810bm_tahvo_remove(struct platform_device *pdev)
+{
+	n810bm_remove();
+	n810bm_tahvo_device = NULL;
+	return 0;
+}
+
+static struct platform_driver n810bm_retu_driver = {
+	.remove		= __devexit_p(n810bm_retu_remove),
+	.driver		= {
+		.name	= "retu-n810bm",
+	}
+};
+
+static struct platform_driver n810bm_tahvo_driver = {
+	.remove		= __devexit_p(n810bm_tahvo_remove),
+	.driver		= {
+		.name	= "tahvo-n810bm",
+	}
+};
+
+static int __init n810bm_modinit(void)
+{
+	int err;
+
+	err = platform_driver_probe(&n810bm_retu_driver, n810bm_retu_probe);
+	if (err)
+		return err;
+	err = platform_driver_probe(&n810bm_tahvo_driver, n810bm_tahvo_probe);
+	if (err) {
+		platform_driver_unregister(&n810bm_retu_driver);
+		return err;
+	}
+
+	return 0;
+}
+module_init(n810bm_modinit);
+
+static void __exit n810bm_modexit(void)
+{
+	platform_driver_unregister(&n810bm_tahvo_driver);
+	platform_driver_unregister(&n810bm_retu_driver);
+}
+module_exit(n810bm_modexit);
+
+MODULE_DESCRIPTION("Nokia n810 battery management");
+MODULE_FIRMWARE(N810BM_PMM_BLOCK_FILENAME);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Michael Buesch");
--- /dev/null
+++ b/drivers/cbus/lipocharge.c
@@ -0,0 +1,183 @@
+/*
+ *   Generic LIPO battery charger
+ *
+ *   Copyright (c) 2010-2011 Michael Buesch <mb@bu3sch.de>
+ *
+ *   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.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#define DEBUG
+
+#include "lipocharge.h"
+
+#include <linux/slab.h>
+
+
+/* Hysteresis constants */
+#define CURRENT_HYST		30 /* mA */
+#define VOLTAGE_HYST		10 /* mV */
+
+/* Threshold constants */
+#define FINISH_CURRENT_PERCENT	3
+
+
+/* Returns the requested first-stage charge current in mA */
+static inline unsigned int get_stage1_charge_current(struct lipocharge *c)
+{
+	/* current = (capacity * C) */
+	return c->capacity * c->rate / 1000;
+}
+
+void lipocharge_init(struct lipocharge *c, struct device *dev)
+{
+	c->dev = dev;
+	c->state = LIPO_IDLE;
+}
+
+void lipocharge_exit(struct lipocharge *c)
+{
+	c->state = LIPO_IDLE;
+}
+
+int lipocharge_start(struct lipocharge *c)
+{
+	int err;
+
+	if (c->state != LIPO_IDLE)
+		return -EBUSY;
+	if (!c->set_current_pwm || !c->emergency)
+		return -EINVAL;
+	if (!c->top_voltage || c->top_voltage > 4200)
+		return -EINVAL;
+
+	c->active_duty_cycle = 0;
+	err = c->set_current_pwm(c, c->active_duty_cycle);
+	if (err)
+		return err;
+	c->state = LIPO_FIRST_STAGE;
+
+	return 0;
+}
+
+void lipocharge_stop(struct lipocharge *c)
+{
+	if (c->state == LIPO_IDLE)
+		return;
+	c->state = LIPO_IDLE;
+}
+
+static int lipocharge_increase_current(struct lipocharge *c,
+				       unsigned int inc_permille)
+{
+	int old_pwm, new_pwm;
+
+	if (c->active_duty_cycle >= c->duty_cycle_max)
+		return 0;
+
+	old_pwm = c->active_duty_cycle;
+	new_pwm = old_pwm + (c->duty_cycle_max * inc_permille / 1000);
+	new_pwm = min(new_pwm, (int)c->duty_cycle_max);
+	c->active_duty_cycle = new_pwm;
+
+	dev_dbg(c->dev, "lipo: Increasing duty_cycle by "
+		"%u permille (0x%02X -> 0x%02X)",
+		inc_permille, old_pwm, new_pwm);
+
+	return c->set_current_pwm(c, c->active_duty_cycle);
+}
+
+static int lipocharge_decrease_current(struct lipocharge *c,
+				       unsigned int dec_permille)
+{
+	int old_pwm, new_pwm;
+
+	if (c->active_duty_cycle <= 0)
+		return 0;
+
+	old_pwm = c->active_duty_cycle;
+	new_pwm = old_pwm - (c->duty_cycle_max * dec_permille / 1000);
+	new_pwm = max(0, new_pwm);
+	c->active_duty_cycle = new_pwm;
+
+	dev_dbg(c->dev, "lipo: Decreasing duty_cycle by "
+		"%u permille (0x%02X -> 0x%02X)",
+		dec_permille, old_pwm, new_pwm);
+
+	return c->set_current_pwm(c, c->active_duty_cycle);
+}
+
+/** lipocharge_update_state - Update the charge state
+ * @c: The context.
+ * @voltage_mV: The measured battery voltage.
+ * @current_mA: The measured charge current.
+ *		negative -> drain.
+ *		positive -> charge.
+ * @temp_K: Battery temperature in K.
+ *
+ * Returns 0 on success, -1 on error.
+ * Returns 1, if the charging process is finished.
+ */
+int lipocharge_update_state(struct lipocharge *c,
+			    unsigned int voltage_mV,
+			    int current_mA,
+			    unsigned int temp_K)
+{
+	int requested_current, current_diff;
+	int err;
+	unsigned int permille;
+
+	//TODO temp
+
+restart:
+	switch (c->state) {
+	case LIPO_IDLE:
+		dev_err(c->dev, "%s: called while idle", __func__);
+		return -EINVAL;
+	case LIPO_FIRST_STAGE:	/* Constant current */
+//printk("GOT %u %d %u\n", voltage_mV, current_mA, temp_K);
+		if (voltage_mV >= c->top_voltage) {
+			/* Float voltage reached.
+			 * Switch charger mode to "constant current" */
+			c->state = LIPO_SECOND_STAGE;
+			dev_dbg(c->dev, "Switched to second charging stage.");
+			goto restart;
+		}
+		/* Float voltage not reached, yet.
+		 * Try to get the requested constant current. */
+		requested_current = get_stage1_charge_current(c);
+		if (current_mA < 0)
+			current_mA = 0;
+		current_diff = requested_current - current_mA;
+		if (abs(requested_current - current_mA) > CURRENT_HYST) {
+			if (current_diff > 0) {
+				/* Increase current */
+				permille = current_diff * 1000 / requested_current;
+				permille /= 2;
+				err = lipocharge_increase_current(c, permille);
+				if (err)
+					return err;
+			} else {
+				/* Decrease current */
+				permille = (-current_diff) * 1000 / requested_current;
+				permille /= 2;
+				err = lipocharge_decrease_current(c, permille);
+				if (err)
+					return err;
+			}
+		}
+		break;
+	case LIPO_SECOND_STAGE:	/* Constant voltage */
+		//TODO
+		break;
+	}
+
+	return 0;
+}
--- /dev/null
+++ b/drivers/cbus/lipocharge.h
@@ -0,0 +1,60 @@
+#ifndef LIPOCHARGE_H_
+#define LIPOCHARGE_H_
+
+#include <linux/types.h>
+#include <linux/device.h>
+
+
+#define LIPORATE(a,b)	(((a) * 1000) + ((b) * 100))
+#define LIPORATE_p6C	LIPORATE(0,6)	/* 0.6C */
+
+enum lipocharge_state {
+	LIPO_IDLE = 0,		/* Not charging */
+	LIPO_FIRST_STAGE,	/* Charging: constant current */
+	LIPO_SECOND_STAGE,	/* Charging: constant voltage */
+};
+
+/** struct lipocharge - A generic LIPO charger
+ *
+ * @capacity: Battery capacity in mAh.
+ * @rate: Charge rate.
+ * @top_voltage: Fully charged voltage, in mV.
+ * @duty_cycle_max: Max value for duty_cycle.
+ *
+ * @set_charge_current: Set the charge current PWM duty cycle.
+ * @emergency: Something went wrong. Force shutdown.
+ */
+struct lipocharge {
+	unsigned int capacity;
+	unsigned int rate;
+	unsigned int top_voltage;
+	unsigned int duty_cycle_max;
+
+	int (*set_current_pwm)(struct lipocharge *c, unsigned int duty_cycle);
+	void (*emergency)(struct lipocharge *c);
+
+	/* internal */
+	struct device *dev;
+	enum lipocharge_state state;
+	unsigned int active_duty_cycle;
+
+	//TODO implement timer to cut power after maximum charge time.
+};
+
+void lipocharge_init(struct lipocharge *c, struct device *dev);
+void lipocharge_exit(struct lipocharge *c);
+
+int lipocharge_start(struct lipocharge *c);
+void lipocharge_stop(struct lipocharge *c);
+
+int lipocharge_update_state(struct lipocharge *c,
+			    unsigned int voltage_mV,
+			    int current_mA,
+			    unsigned int temp_K);
+
+static inline bool lipocharge_is_charging(struct lipocharge *c)
+{
+	return (c->state != LIPO_IDLE);
+}
+
+#endif /* LIPOCHARGE_H_ */
--- a/drivers/cbus/cbus.c
+++ b/drivers/cbus/cbus.c
@@ -36,6 +36,7 @@
 #include <linux/gpio.h>
 #include <linux/platform_device.h>
 #include <linux/platform_data/cbus.h>
+#include <linux/reboot.h>
 
 #include "cbus.h"
 
@@ -326,6 +327,13 @@ static void __exit cbus_bus_exit(void)
 }
 module_exit(cbus_bus_exit);
 
+void cbus_emergency(void)
+{
+	machine_power_off();
+	panic("cbus: Failed to halt machine in emergency state\n");
+}
+EXPORT_SYMBOL(cbus_emergency);
+
 MODULE_DESCRIPTION("CBUS serial protocol");
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Juha Yrj<72>l<EFBFBD>");
--- a/drivers/cbus/cbus.h
+++ b/drivers/cbus/cbus.h
@@ -27,4 +27,6 @@ extern int cbus_read_reg(struct device *
 extern int cbus_write_reg(struct device *, unsigned dev, unsigned reg,
 		unsigned val);
 
+void cbus_emergency(void) __noreturn;
+
 #endif /* __DRIVERS_CBUS_CBUS_H */
--- a/drivers/cbus/retu.c
+++ b/drivers/cbus/retu.c
@@ -399,6 +399,11 @@ static int retu_allocate_children(struct
 	if (!child)
 		return -ENOMEM;
 
+	child = retu_allocate_child("retu-n810bm", parent, irq_base,
+			RETU_INT_ADCS, -1, 1);
+	if (!child)
+		return -ENOMEM;
+
 	return 0;
 }
 
--- a/drivers/cbus/tahvo.c
+++ b/drivers/cbus/tahvo.c
@@ -129,6 +129,7 @@ void tahvo_set_clear_reg_bits(struct dev
 	__tahvo_write_reg(tahvo, reg, w);
 	mutex_unlock(&tahvo->mutex);
 }
+EXPORT_SYMBOL(tahvo_set_clear_reg_bits);
 
 static irqreturn_t tahvo_irq_handler(int irq, void *_tahvo)
 {
@@ -292,6 +293,11 @@ static int tahvo_allocate_children(struc
 	if (!child)
 		return -ENOMEM;
 
+	child = tahvo_allocate_child("tahvo-n810bm", parent,
+				     irq_base + TAHVO_INT_BATCURR);
+	if (!child)
+		return -ENOMEM;
+
 	return 0;
 }