Add hdq and bq27000 driver.

4 files changed, 1007 insertions, 0 deletions

diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index bdbc4f73fcd..2acfcd12e48 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -103,4 +103,16 @@ config CHARGER_PCF50633
 	help
 	 Say Y to include support for NXP PCF50633 Main Battery Charger.
 
+config BATTERY_BQ27000_HDQ
+	tristate "BQ27000 HDQ battery monitor driver"
+	help
+	  Say Y to enable support for the battery on the Neo Freerunner
+
+config HDQ_GPIO_BITBANG
+	bool "Generic gpio based HDQ bitbang"
+	help
+	  Say Y to enable supoort for generic gpio based HDQ bitbang driver.
+	  This can not be built as a module.
+
 endif # POWER_SUPPLY
+
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index 380d17c9ae2..027ee9fdbcd 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -28,3 +28,6 @@ obj-$(CONFIG_BATTERY_BQ27x00)	+= bq27x00_battery.o
 obj-$(CONFIG_BATTERY_DA9030)	+= da9030_battery.o
 obj-$(CONFIG_BATTERY_MAX17040)	+= max17040_battery.o
 obj-$(CONFIG_CHARGER_PCF50633)	+= pcf50633-charger.o
+obj-$(CONFIG_BATTERY_BQ27000_HDQ)	+= bq27000_battery.o
+
+obj-$(CONFIG_HDQ_GPIO_BITBANG)  += hdq.o
diff --git a/drivers/power/bq27000_battery.c b/drivers/power/bq27000_battery.c
new file mode 100644
index 00000000000..32655dce1f3
--- /dev/null
+++ b/drivers/power/bq27000_battery.c
@@ -0,0 +1,477 @@
+/*
+ * Driver for batteries with bq27000 chips inside via HDQ
+ *
+ * Copyright 2008 Openmoko, Inc
+ * Andy Green <andy@openmoko.com>
+ *
+ * based on ds2760 driver, original copyright notice for that --->
+ *
+ * Copyright © 2007 Anton Vorontsov
+ *	       2004-2007 Matt Reimer
+ *	       2004 Szabolcs Gyurko
+ *
+ * Use consistent with the GNU GPL is permitted,
+ * provided that this copyright notice is
+ * preserved in its entirety in all copies and derived works.
+ *
+ * Author:  Anton Vorontsov <cbou@mail.ru>
+ *	    February 2007
+ *
+ *	    Matt Reimer <mreimer@vpop.net>
+ *	    April 2004, 2005, 2007
+ *
+ *	    Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
+ *	    September 2004
+ */
+
+#include <linux/module.h>
+#include <linux/param.h>
+#include <linux/jiffies.h>
+#include <linux/delay.h>
+#include <linux/pm.h>
+#include <linux/workqueue.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/bq27000_battery.h>
+
+enum bq27000_regs {
+	/* RAM regs */
+		/* read-write after this */
+	BQ27000_CTRL = 0, /* Device Control Register */
+	BQ27000_MODE, /* Device Mode Register */
+	BQ27000_AR_L, /* At-Rate H L */
+	BQ27000_AR_H,
+		/* read-only after this */
+	BQ27000_ARTTE_L, /* At-Rate Time To Empty H L */
+	BQ27000_ARTTE_H,
+	BQ27000_TEMP_L, /* Reported Temperature H L */
+	BQ27000_TEMP_H,
+	BQ27000_VOLT_L, /* Reported Voltage H L */
+	BQ27000_VOLT_H,
+	BQ27000_FLAGS, /* Status Flags */
+	BQ27000_RSOC, /* Relative State of Charge */
+	BQ27000_NAC_L, /* Nominal Available Capacity H L */
+	BQ27000_NAC_H,
+	BQ27000_CACD_L, /* Discharge Compensated H L */
+	BQ27000_CACD_H,
+	BQ27000_CACT_L, /* Temperature Compensated H L */
+	BQ27000_CACT_H,
+	BQ27000_LMD_L, /* Last measured discharge H L */
+	BQ27000_LMD_H,
+	BQ27000_AI_L, /* Average Current H L */
+	BQ27000_AI_H,
+	BQ27000_TTE_L, /* Time to Empty H L */
+	BQ27000_TTE_H,
+	BQ27000_TTF_L, /* Time to Full H L */
+	BQ27000_TTF_H,
+	BQ27000_SI_L, /* Standby Current H L */
+	BQ27000_SI_H,
+	BQ27000_STTE_L, /* Standby Time To Empty H L */
+	BQ27000_STTE_H,
+	BQ27000_MLI_L, /* Max Load Current H L */
+	BQ27000_MLI_H,
+	BQ27000_MLTTE_L, /* Max Load Time To Empty H L */
+	BQ27000_MLTTE_H,
+	BQ27000_SAE_L, /* Available Energy H L */
+	BQ27000_SAE_H,
+	BQ27000_AP_L, /* Available Power H L */
+	BQ27000_AP_H,
+	BQ27000_TTECP_L, /* Time to Empty at Constant Power H L */
+	BQ27000_TTECP_H,
+	BQ27000_CYCL_L, /* Cycle count since learning cycle H L */
+	BQ27000_CYCL_H,
+	BQ27000_CYCT_L, /* Cycle Count Total H L */
+	BQ27000_CYCT_H,
+	BQ27000_CSOC, /* Compensated State Of Charge */
+	/* EEPROM regs */
+		/* read-write after this */
+	BQ27000_EE_EE_EN = 0x6e, /* EEPROM Program Enable */
+	BQ27000_EE_ILMD = 0x76, /* Initial Last Measured Discharge High Byte */
+	BQ27000_EE_SEDVF, /* Scaled EDVF Threshold */
+	BQ27000_EE_SEDV1, /* Scaled EDV1 Threshold */
+	BQ27000_EE_ISLC, /* Initial Standby Load Current */
+	BQ27000_EE_DMFSD, /* Digital Magnitude Filter and Self Discharge */
+	BQ27000_EE_TAPER, /* Aging Estimate Enable, Charge Termination Taper */
+	BQ27000_EE_PKCFG, /* Pack Configuration Values */
+	BQ27000_EE_IMLC, /* Initial Max Load Current or ID #3 */
+	BQ27000_EE_DCOMP, /* Discharge rate compensation constants or ID #2 */
+	BQ27000_EE_TCOMP, /* Temperature Compensation constants or ID #1 */
+};
+
+enum bq27000_status_flags {
+	BQ27000_STATUS_CHGS = 0x80, /* 1 = being charged */
+	BQ27000_STATUS_NOACT = 0x40, /* 1 = no activity */
+	BQ27000_STATUS_IMIN = 0x20, /* 1 = Lion taper current mode */
+	BQ27000_STATUS_CI = 0x10, /* 1 = capacity likely  innacurate */
+	BQ27000_STATUS_CALIP = 0x08, /* 1 = calibration in progress */
+	BQ27000_STATUS_VDQ = 0x04, /* 1 = capacity should be accurate */
+	BQ27000_STATUS_EDV1 = 0x02, /* 1 = end of discharge.. <6% left */
+	BQ27000_STATUS_EDVF = 0x01, /* 1 = no, it's really empty now */
+};
+
+#define NANOVOLTS_UNIT 3750
+
+struct bq27000_bat_regs {
+	int		ai;
+	int		flags;
+	int		lmd;
+	int		rsoc;
+	int		temp;
+	int		tte;
+	int		ttf;
+	int		volt;
+};
+
+struct bq27000_device_info {
+	struct device *dev;
+	struct power_supply bat;
+	struct power_supply ac;
+	struct power_supply usb;
+	struct delayed_work work;
+	struct bq27000_platform_data *pdata;
+
+	struct bq27000_bat_regs regs;
+};
+
+static unsigned int cache_time = 5000;
+module_param(cache_time, uint, 0644);
+MODULE_PARM_DESC(cache_time, "cache time in milliseconds");
+
+/*
+ * reading 16 bit values over HDQ has a special hazard where the
+ * hdq device firmware can update the 16-bit register during the time we
+ * read the two halves.  TI document SLUS556D recommends the algorithm here
+ * to avoid trouble
+ */
+
+static int hdq_read16(struct bq27000_device_info *di, int address)
+{
+	int acc;
+	int high;
+	int retries = 3;
+
+	while (retries--) {
+
+		high = (di->pdata->hdq_read)(address + 1); /* high part */
+
+		if (high < 0)
+			return high;
+		acc = (di->pdata->hdq_read)(address);
+		if (acc < 0)
+			return acc;
+
+		/* confirm high didn't change between reading it and low */
+		if (high == (di->pdata->hdq_read)(address + 1))
+			return (high << 8) | acc;
+	}
+
+	return -ETIME;
+}
+
+static void bq27000_battery_external_power_changed(struct power_supply *psy)
+{
+	struct bq27000_device_info *di = container_of(psy, struct bq27000_device_info, bat);
+
+	dev_dbg(di->dev, "%s\n", __FUNCTION__);
+	schedule_delayed_work(&di->work, 0);
+}
+
+static int bq27000_battery_get_property(struct power_supply *psy,
+				       enum power_supply_property psp,
+				       union power_supply_propval *val)
+{
+	int n;
+	struct bq27000_device_info *di = container_of(psy, struct bq27000_device_info, bat);
+
+	if (di->regs.rsoc < 0 && psp != POWER_SUPPLY_PROP_PRESENT)
+		return -ENODEV;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_STATUS:
+		val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
+
+		if (!di->pdata->get_charger_online_status)
+			goto use_bat;
+		if ((di->pdata->get_charger_online_status)()) {
+			/*
+			 * charger is definitively present
+			 * we report our state in terms of what it says it
+			 * is doing
+			 */
+			if (!di->pdata->get_charger_active_status)
+				goto use_bat;
+
+			if ((di->pdata->get_charger_active_status)()) {
+				val->intval = POWER_SUPPLY_STATUS_CHARGING;
+				break;
+			}
+			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+			break;
+		}
+
+		/*
+		 * platform provided definite indication of charger presence,
+		 * and it is telling us it isn't there... but we are on so we
+		 * must be running from battery --->
+		 */
+
+		val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+		break;
+
+use_bat:
+		/*
+		 * either the charger is not connected, or the
+		 * platform doesn't give info about charger, use battery state
+		 * but... battery state can be out of date by 4 seconds or
+		 * so... use the platform callbacks if possible.
+		 */
+
+		/* no real activity on the battery */
+		if (di->regs.ai < 2) {
+			if (!di->regs.ttf)
+				val->intval = POWER_SUPPLY_STATUS_FULL;
+			else
+				val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+			break;
+		}
+		/* power is actually going in or out... */
+		if (di->regs.flags < 0)
+			return di->regs.flags;
+		if (di->regs.flags & BQ27000_STATUS_CHGS)
+			val->intval = POWER_SUPPLY_STATUS_CHARGING;
+		else
+			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+		break;
+	case POWER_SUPPLY_PROP_HEALTH:
+		val->intval = POWER_SUPPLY_HEALTH_UNKNOWN;
+		/* Do we have accurate readings... */
+		if (di->regs.flags < 0)
+			return di->regs.flags;
+		if (di->regs.flags & BQ27000_STATUS_VDQ)
+			val->intval = POWER_SUPPLY_HEALTH_GOOD;
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		if (di->regs.volt < 0)
+			return di->regs.volt;
+		/* mV -> uV */
+		val->intval = di->regs.volt * 1000;
+		break;
+	case POWER_SUPPLY_PROP_CURRENT_NOW:
+		if (di->regs.flags < 0)
+			return di->regs.flags;
+		if (di->regs.flags & BQ27000_STATUS_CHGS)
+			n = -NANOVOLTS_UNIT;
+		else
+			n = NANOVOLTS_UNIT;
+		if (di->regs.ai < 0)
+			return di->regs.ai;
+		val->intval = (di->regs.ai * n) / di->pdata->rsense_mohms;
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_FULL:
+		if (di->regs.lmd < 0)
+			return di->regs.lmd;
+		val->intval = (di->regs.lmd * 3570) / di->pdata->rsense_mohms;
+		break;
+	case POWER_SUPPLY_PROP_TEMP:
+		if (di->regs.temp < 0)
+			return di->regs.temp;
+		/* K (in 0.25K units) is 273.15 up from C (in 0.1C)*/
+		/* 10926 = 27315 * 4 / 10 */
+		val->intval = (((long)di->regs.temp * 10l) - 10926) / 4;
+		break;
+	case POWER_SUPPLY_PROP_TECHNOLOGY:
+		val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
+		break;
+	case POWER_SUPPLY_PROP_CAPACITY:
+		val->intval = di->regs.rsoc;
+		if (val->intval < 0)
+			return val->intval;
+		break;
+	case POWER_SUPPLY_PROP_PRESENT:
+		val->intval = !(di->regs.rsoc < 0);
+		break;
+	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
+		if (di->regs.tte < 0)
+			return di->regs.tte;
+		val->intval = 60 * di->regs.tte;
+		break;
+	case POWER_SUPPLY_PROP_TIME_TO_FULL_NOW:
+		if (di->regs.ttf < 0)
+			return di->regs.ttf;
+		val->intval = 60 * di->regs.ttf;
+		break;
+	case POWER_SUPPLY_PROP_ONLINE:
+		if (di->pdata->get_charger_online_status)
+			val->intval = (di->pdata->get_charger_online_status)();
+		else
+			return -EINVAL;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void bq27000_battery_work(struct work_struct *work)
+{
+	struct bq27000_device_info *di =
+		container_of(work, struct bq27000_device_info, work.work);
+
+	if ((di->pdata->hdq_initialized)()) {
+		struct bq27000_bat_regs regs;
+
+		regs.ai    = hdq_read16(di, BQ27000_AI_L);
+		regs.flags = (di->pdata->hdq_read)(BQ27000_FLAGS);
+		regs.lmd   = hdq_read16(di, BQ27000_LMD_L);
+		regs.rsoc  = (di->pdata->hdq_read)(BQ27000_RSOC);
+		regs.temp  = hdq_read16(di, BQ27000_TEMP_L);
+		regs.tte   = hdq_read16(di, BQ27000_TTE_L);
+		regs.ttf   = hdq_read16(di, BQ27000_TTF_L);
+		regs.volt  = hdq_read16(di, BQ27000_VOLT_L);
+
+		if (memcmp (&regs, &di->regs, sizeof(regs)) != 0) {
+			di->regs = regs;
+			power_supply_changed(&di->bat);
+		}
+	}
+
+	if (!schedule_delayed_work(&di->work, cache_time))
+		dev_err(di->dev, "battery service reschedule failed\n");
+}
+
+static enum power_supply_property bq27000_battery_props[] = {
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_HEALTH,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_CURRENT_NOW,
+	POWER_SUPPLY_PROP_CHARGE_FULL,
+	POWER_SUPPLY_PROP_TEMP,
+	POWER_SUPPLY_PROP_TECHNOLOGY,
+	POWER_SUPPLY_PROP_PRESENT,
+	POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
+	POWER_SUPPLY_PROP_TIME_TO_FULL_NOW,
+	POWER_SUPPLY_PROP_CAPACITY,
+	POWER_SUPPLY_PROP_ONLINE
+};
+
+static int bq27000_battery_probe(struct platform_device *pdev)
+{
+	int retval = 0;
+	struct bq27000_device_info *di;
+	struct bq27000_platform_data *pdata;
+
+	dev_info(&pdev->dev, "BQ27000 Battery Driver (C) 2008 Openmoko, Inc\n");
+
+	di = kzalloc(sizeof(*di), GFP_KERNEL);
+	if (!di) {
+		retval = -ENOMEM;
+		goto di_alloc_failed;
+	}
+
+	platform_set_drvdata(pdev, di);
+
+	pdata = pdev->dev.platform_data;
+	di->dev		= &pdev->dev;
+	/* di->w1_dev	     = pdev->dev.parent; */
+	di->bat.name	   = pdata->name;
+	di->bat.type	   = POWER_SUPPLY_TYPE_BATTERY;
+	di->bat.properties     = bq27000_battery_props;
+	di->bat.num_properties = ARRAY_SIZE(bq27000_battery_props);
+	di->bat.get_property   = bq27000_battery_get_property;
+	di->bat.external_power_changed =
+				  bq27000_battery_external_power_changed;
+	di->bat.use_for_apm = 1;
+	di->pdata = pdata;
+
+	retval = power_supply_register(&pdev->dev, &di->bat);
+	if (retval) {
+		dev_err(di->dev, "failed to register battery\n");
+		goto batt_failed;
+	}
+
+	INIT_DELAYED_WORK(&di->work, bq27000_battery_work);
+
+	if (!schedule_delayed_work(&di->work, 0))
+		dev_err(di->dev, "failed to schedule bq27000_battery_work\n");
+
+	return 0;
+
+batt_failed:
+	kfree(di);
+di_alloc_failed:
+	return retval;
+}
+
+static int bq27000_battery_remove(struct platform_device *pdev)
+{
+	struct bq27000_device_info *di = platform_get_drvdata(pdev);
+
+	cancel_delayed_work(&di->work);
+
+	power_supply_unregister(&di->bat);
+
+	return 0;
+}
+
+void bq27000_charging_state_change(struct platform_device *pdev)
+{
+	struct bq27000_device_info *di = platform_get_drvdata(pdev);
+
+	if (!di)
+	    return;
+}
+EXPORT_SYMBOL_GPL(bq27000_charging_state_change);
+
+#ifdef CONFIG_PM
+
+static int bq27000_battery_suspend(struct platform_device *pdev,
+				  pm_message_t state)
+{
+	struct bq27000_device_info *di = platform_get_drvdata(pdev);
+
+	cancel_delayed_work(&di->work);
+	return 0;
+}
+
+static int bq27000_battery_resume(struct platform_device *pdev)
+{
+	struct bq27000_device_info *di = platform_get_drvdata(pdev);
+
+	schedule_delayed_work(&di->work, 0);
+	return 0;
+}
+
+#else
+
+#define bq27000_battery_suspend NULL
+#define bq27000_battery_resume NULL
+
+#endif /* CONFIG_PM */
+
+static struct platform_driver bq27000_battery_driver = {
+	.driver = {
+		.name = "bq27000-battery",
+	},
+	.probe	  = bq27000_battery_probe,
+	.remove   = bq27000_battery_remove,
+	.suspend  = bq27000_battery_suspend,
+	.resume	  = bq27000_battery_resume,
+};
+
+static int __init bq27000_battery_init(void)
+{
+	return platform_driver_register(&bq27000_battery_driver);
+}
+
+static void __exit bq27000_battery_exit(void)
+{
+	platform_driver_unregister(&bq27000_battery_driver);
+}
+
+module_init(bq27000_battery_init);
+module_exit(bq27000_battery_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Andy Green <andy@openmoko.com>");
+MODULE_DESCRIPTION("bq27000 battery driver");
diff --git a/drivers/power/hdq.c b/drivers/power/hdq.c
new file mode 100644
index 00000000000..f03fabfb1aa
--- /dev/null
+++ b/drivers/power/hdq.c
@@ -0,0 +1,515 @@
+/*
+ * HDQ generic GPIO bitbang driver using FIQ
+ *
+ * (C) 2006-2007 by Openmoko, Inc.
+ * Author: Andy Green <andy@openmoko.com>
+ * 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 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/hdq.h>
+
+#define HDQ_READ 0
+#define HDQ_WRITE 0x80
+
+enum hdq_bitbang_states {
+	HDQB_IDLE = 0,
+	HDQB_TX_BREAK,
+	HDQB_TX_BREAK_RECOVERY,
+	HDQB_ADS_CALC,
+	HDQB_ADS_LOW,
+	HDQB_ADS_HIGH,
+	HDQB_WAIT_RX,
+	HDQB_DATA_RX_LOW,
+	HDQB_DATA_RX_HIGH,
+	HDQB_WAIT_TX,
+};
+
+static struct hdq_priv {
+	u8 hdq_probed; /* nonzero after HDQ driver probed */
+	struct mutex hdq_lock; /* if you want to use hdq, you have to take lock */
+	unsigned long hdq_gpio_pin; /* GTA02 = GPD14 which pin to meddle with */
+	u8 hdq_ads; /* b7..b6 = register address, b0 = r/w */
+	u8 hdq_tx_data; /* data to tx for write action */
+	u8 hdq_rx_data; /* data received in read action */
+	u8 hdq_request_ctr; /* incremented by "user" to request a transfer */
+	u8 hdq_transaction_ctr; /* incremented after each transfer */
+	u8 hdq_error; /* 0 = no error */
+	u8 hdq_ctr;
+	u8 hdq_ctr2;
+	u8 hdq_bit;
+	u8 hdq_shifter;
+	u8 hdq_tx_data_done;
+	enum hdq_bitbang_states hdq_state;
+	int reported_error;
+
+	struct hdq_platform_data *pdata;
+} hdq_priv;
+
+
+static void hdq_bad(void)
+{
+	if (!hdq_priv.reported_error)
+		printk(KERN_ERR "HDQ error: %d\n", hdq_priv.hdq_error);
+	hdq_priv.reported_error = 1;
+}
+
+static void hdq_good(void)
+{
+	if (hdq_priv.reported_error)
+		printk(KERN_INFO "HDQ responds again\n");
+	hdq_priv.reported_error = 0;
+}
+
+int hdq_fiq_handler(void)
+{
+	if (!hdq_priv.hdq_probed)
+		return 0;
+
+	switch (hdq_priv.hdq_state) {
+	case HDQB_IDLE:
+		if (hdq_priv.hdq_request_ctr == hdq_priv.hdq_transaction_ctr)
+			break;
+		hdq_priv.hdq_ctr = 250 / HDQ_SAMPLE_PERIOD_US;
+		hdq_priv.pdata->gpio_set(0);
+		hdq_priv.pdata->gpio_dir_out();
+		hdq_priv.hdq_tx_data_done = 0;
+		hdq_priv.hdq_state = HDQB_TX_BREAK;
+		break;
+
+	case HDQB_TX_BREAK: /* issue low for > 190us */
+		if (--hdq_priv.hdq_ctr == 0) {
+			hdq_priv.hdq_ctr = 60 / HDQ_SAMPLE_PERIOD_US;
+			hdq_priv.hdq_state = HDQB_TX_BREAK_RECOVERY;
+			hdq_priv.pdata->gpio_set(1);
+		}
+		break;
+
+	case HDQB_TX_BREAK_RECOVERY: /* issue low for > 40us */
+		if (--hdq_priv.hdq_ctr)
+			break;
+		hdq_priv.hdq_shifter = hdq_priv.hdq_ads;
+		hdq_priv.hdq_bit = 8; /* 8 bits of ads / rw */
+		hdq_priv.hdq_tx_data_done = 0; /* doing ads */
+		/* fallthru on last one */
+	case HDQB_ADS_CALC:
+		if (hdq_priv.hdq_shifter & 1)
+			hdq_priv.hdq_ctr = 50 / HDQ_SAMPLE_PERIOD_US;
+		else
+			hdq_priv.hdq_ctr = 120 / HDQ_SAMPLE_PERIOD_US;
+		/* carefully precompute the other phase length */
+		hdq_priv.hdq_ctr2 = (210 - (hdq_priv.hdq_ctr * HDQ_SAMPLE_PERIOD_US)) /
+				HDQ_SAMPLE_PERIOD_US;
+		hdq_priv.hdq_state = HDQB_ADS_LOW;
+		hdq_priv.hdq_shifter >>= 1;
+		hdq_priv.hdq_bit--;
+		hdq_priv.pdata->gpio_set(0);
+		break;
+
+	case HDQB_ADS_LOW:
+		if (--hdq_priv.hdq_ctr)
+			break;
+		hdq_priv.pdata->gpio_set(1);
+		hdq_priv.hdq_state = HDQB_ADS_HIGH;
+		break;
+
+	case HDQB_ADS_HIGH:
+		if (--hdq_priv.hdq_ctr2 > 1) /* account for HDQB_ADS_CALC */
+			break;
+		if (hdq_priv.hdq_bit) { /* more bits to do */
+			hdq_priv.hdq_state = HDQB_ADS_CALC;
+			break;
+		}
+		/* no more bits, wait it out until hdq_priv.hdq_ctr2 exhausted */
+		if (hdq_priv.hdq_ctr2)
+			break;
+		/* ok no more bits and very last state */
+		hdq_priv.hdq_ctr = 60 / HDQ_SAMPLE_PERIOD_US;
+		/* FIXME 0 = read */
+		if (hdq_priv.hdq_ads & 0x80) { /* write the byte out */
+			 /* set delay before payload */
+			hdq_priv.hdq_ctr = 300 / HDQ_SAMPLE_PERIOD_US;
+ 			/* already high, no need to write */
+			hdq_priv.hdq_state = HDQB_WAIT_TX;
+			break;
+		}
+		/* read the next byte */
+		hdq_priv.hdq_bit = 8; /* 8 bits of data */
+		hdq_priv.hdq_ctr = 2500 / HDQ_SAMPLE_PERIOD_US;
+		hdq_priv.hdq_state = HDQB_WAIT_RX;
+		hdq_priv.pdata->gpio_dir_in();
+		break;
+
+	case HDQB_WAIT_TX: /* issue low for > 40us */
+		if (--hdq_priv.hdq_ctr)
+			break;
+		if (!hdq_priv.hdq_tx_data_done) { /* was that the data sent? */
+			hdq_priv.hdq_tx_data_done++;
+			hdq_priv.hdq_shifter = hdq_priv.hdq_tx_data;
+			hdq_priv.hdq_bit = 8; /* 8 bits of data */
+			hdq_priv.hdq_state = HDQB_ADS_CALC; /* start sending */
+			break;
+		}
+		hdq_priv.hdq_error = 0;
+		hdq_priv.hdq_transaction_ctr = hdq_priv.hdq_request_ctr;
+		hdq_priv.hdq_state = HDQB_IDLE; /* all tx is done */
+		/* idle in input mode, it's pulled up by 10K */
+		hdq_priv.pdata->gpio_dir_in();
+		break;
+
+	case HDQB_WAIT_RX: /* wait for battery to talk to us */
+		if (hdq_priv.pdata->gpio_get() == 0) {
+			/* it talks to us! */
+			hdq_priv.hdq_ctr2 = 1;
+			hdq_priv.hdq_bit = 8; /* 8 bits of data */
+			/* timeout */
+			hdq_priv.hdq_ctr = 500 / HDQ_SAMPLE_PERIOD_US;
+			hdq_priv.hdq_state = HDQB_DATA_RX_LOW;
+			break;
+		}
+		if (--hdq_priv.hdq_ctr == 0) { /* timed out, error */
+			hdq_priv.hdq_error = 1;
+			hdq_priv.hdq_transaction_ctr = hdq_priv.hdq_request_ctr;
+			hdq_priv.hdq_state = HDQB_IDLE; /* abort */
+		}
+		break;
+
+	/*
+	 * HDQ basically works by measuring the low time of the bit cell
+	 * 32-50us --> '1', 80 - 145us --> '0'
+	 */
+
+	case HDQB_DATA_RX_LOW:
+		if (hdq_priv.pdata->gpio_get()) {
+			hdq_priv.hdq_rx_data >>= 1;
+			if (hdq_priv.hdq_ctr2 <= (65 / HDQ_SAMPLE_PERIOD_US))
+				hdq_priv.hdq_rx_data |= 0x80;
+
+			if (--hdq_priv.hdq_bit == 0) {
+				hdq_priv.hdq_error = 0;
+				hdq_priv.hdq_transaction_ctr =
+							hdq_priv.hdq_request_ctr;
+
+				hdq_priv.hdq_state = HDQB_IDLE;
+			} else
+				hdq_priv.hdq_state = HDQB_DATA_RX_HIGH;
+			/* timeout */
+			hdq_priv.hdq_ctr = 1000 / HDQ_SAMPLE_PERIOD_US;
+			hdq_priv.hdq_ctr2 = 1;
+			break;
+		}
+		hdq_priv.hdq_ctr2++;
+		if (--hdq_priv.hdq_ctr)
+			break;
+		 /* timed out, error */
+		hdq_priv.hdq_error = 2;
+		hdq_priv.hdq_transaction_ctr = hdq_priv.hdq_request_ctr;
+		hdq_priv.hdq_state = HDQB_IDLE; /* abort */
+		break;
+
+	case HDQB_DATA_RX_HIGH:
+		if (!hdq_priv.pdata->gpio_get()) {
+			/* it talks to us! */
+			hdq_priv.hdq_ctr2 = 1;
+			/* timeout */
+			hdq_priv.hdq_ctr = 400 / HDQ_SAMPLE_PERIOD_US;
+			hdq_priv.hdq_state = HDQB_DATA_RX_LOW;
+			break;
+		}
+		if (--hdq_priv.hdq_ctr)
+			break;
+		/* timed out, error */
+		hdq_priv.hdq_error = 3;
+		hdq_priv.hdq_transaction_ctr = hdq_priv.hdq_request_ctr;
+
+		/* we're in input mode already */
+		hdq_priv.hdq_state = HDQB_IDLE; /* abort */
+		break;
+	}
+
+	/* Are we interested in keeping the FIQ source alive ? */
+	if (hdq_priv.hdq_state != HDQB_IDLE)
+		return 1;
+	else
+		return 0;
+}
+static int fiq_busy(void)
+{
+	int request = (volatile u8)hdq_priv.hdq_request_ctr;
+	int transact = (volatile u8)hdq_priv.hdq_transaction_ctr;
+
+
+	return (request != transact);
+}
+
+int hdq_initialized(void)
+{
+	return hdq_priv.hdq_probed;
+}
+EXPORT_SYMBOL_GPL(hdq_initialized);
+
+int hdq_read(int address)
+{
+	int count_sleeps = 5;
+	int ret = -ETIME;
+
+	if (!hdq_priv.hdq_probed)
+		return -EINVAL;
+
+	mutex_lock(&hdq_priv.hdq_lock);
+
+	hdq_priv.hdq_error = 0;
+	hdq_priv.hdq_ads = address | HDQ_READ;
+	hdq_priv.hdq_request_ctr++;
+	hdq_priv.pdata->kick_fiq();
+	/*
+	 * FIQ takes care of it while we block our calling process
+	 * But we're not spinning -- other processes run normally while
+	 * we wait for the result
+	 */
+	while (count_sleeps--) {
+		msleep(10); /* valid transaction always completes in < 10ms */
+
+		if (fiq_busy())
+			continue;
+
+		if (hdq_priv.hdq_error) {
+			hdq_bad();
+			goto done; /* didn't see a response in good time */
+		}
+		hdq_good();
+
+		ret = hdq_priv.hdq_rx_data;
+		goto done;
+	}
+
+done:
+	mutex_unlock(&hdq_priv.hdq_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hdq_read);
+
+int hdq_write(int address, u8 data)
+{
+	int count_sleeps = 5;
+	int ret = -ETIME;
+
+	if (!hdq_priv.hdq_probed)
+		return -EINVAL;
+
+	mutex_lock(&hdq_priv.hdq_lock);
+
+	hdq_priv.hdq_error = 0;
+	hdq_priv.hdq_ads = address | HDQ_WRITE;
+	hdq_priv.hdq_tx_data = data;
+	hdq_priv.hdq_request_ctr++;
+	hdq_priv.pdata->kick_fiq();
+	/*
+	 * FIQ takes care of it while we block our calling process
+	 * But we're not spinning -- other processes run normally while
+	 * we wait for the result
+	 */
+	while (count_sleeps--) {
+		msleep(10); /* valid transaction always completes in < 10ms */
+
+		if (fiq_busy())
+			continue; /* something bad with FIQ */
+
+		if (hdq_priv.hdq_error) {
+			hdq_bad();
+			goto done; /* didn't see a response in good time */
+		}
+		hdq_good();
+
+		ret = 0;
+		goto done;
+	}
+
+done:
+	mutex_unlock(&hdq_priv.hdq_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hdq_write);
+
+/* sysfs */
+
+static ssize_t hdq_sysfs_dump(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	int n;
+	int v;
+	u8 u8a[128]; /* whole address space for HDQ */
+	char *end = buf;
+
+	if (!hdq_priv.hdq_probed)
+		return -EINVAL;
+
+	/* the dump does not take care about 16 bit regs, because at this
+	 * bus level we don't know about the chip details
+	 */
+	for (n = 0; n < sizeof(u8a); n++) {
+		v = hdq_read(n);
+		if (v < 0)
+			goto bail;
+		u8a[n] = v;
+	}
+
+	for (n = 0; n < sizeof(u8a); n += 16) {
+		hex_dump_to_buffer(u8a + n, sizeof(u8a), 16, 1, end, 4096, 0);
+		end += strlen(end);
+		*end++ = '\n';
+		*end = '\0';
+	}
+	return (end - buf);
+
+bail:
+	return sprintf(buf, "ERROR %d\n", v);
+}
+
+/* you write by <address> <data>, eg, "34 128" */
+
+#define atoi(str) simple_strtoul(((str != NULL) ? str : ""), NULL, 0)
+
+static ssize_t hdq_sysfs_write(struct device *dev,
+			       struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	const char *end = buf + count;
+	int address = atoi(buf);
+
+	if (!hdq_priv.hdq_probed)
+		return -EINVAL;
+
+	while ((buf != end) && (*buf != ' '))
+		buf++;
+	if (buf >= end)
+		return 0;
+	while ((buf < end) && (*buf == ' '))
+		buf++;
+	if (buf >= end)
+		return 0;
+
+	hdq_write(address, atoi(buf));
+
+	return count;
+}
+
+static DEVICE_ATTR(dump, 0400, hdq_sysfs_dump, NULL);
+static DEVICE_ATTR(write, 0600, NULL, hdq_sysfs_write);
+
+static struct attribute *hdq_sysfs_entries[] = {
+	&dev_attr_dump.attr,
+	&dev_attr_write.attr,
+	NULL
+};
+
+static struct attribute_group hdq_attr_group = {
+	.name	= "hdq",
+	.attrs	= hdq_sysfs_entries,
+};
+
+
+#ifdef CONFIG_PM
+static int hdq_suspend(struct platform_device *pdev, pm_message_t state)
+{
+	/* after 18s of this, the battery monitor will also go to sleep */
+	hdq_priv.pdata->gpio_dir_in();
+	hdq_priv.pdata->disable_fiq();
+	return 0;
+}
+
+static int hdq_resume(struct platform_device *pdev)
+{
+	hdq_priv.pdata->gpio_set(1);
+	hdq_priv.pdata->gpio_dir_out();
+	hdq_priv.pdata->enable_fiq();
+	return 0;
+}
+#endif
+
+static int __init hdq_probe(struct platform_device *pdev)
+{
+	struct resource *r = platform_get_resource(pdev, 0, 0);
+	int ret;
+	struct hdq_platform_data *pdata = pdev->dev.platform_data;
+
+	if (!r || !pdata)
+		return -EINVAL;
+
+	platform_set_drvdata(pdev, NULL);
+
+	mutex_init(&hdq_priv.hdq_lock);
+
+	/* set our HDQ comms pin from the platform data */
+	hdq_priv.hdq_gpio_pin = r->start;
+	hdq_priv.pdata = pdata;
+
+	hdq_priv.pdata->gpio_set(1);
+	hdq_priv.pdata->gpio_dir_out();
+
+	/* Initialize FIQ */
+	if (hdq_priv.pdata->enable_fiq() < 0) {
+		dev_err(&pdev->dev, "Could not enable FIQ source\n");
+		return -EINVAL;
+	}
+
+	ret = sysfs_create_group(&pdev->dev.kobj, &hdq_attr_group);
+	if (ret)
+		return ret;
+
+	hdq_priv.hdq_probed = 1; /* we are ready to do stuff now */
+
+	/*
+	 * if wanted, users can defer registration of devices
+	 * that depend on HDQ until after we register, and can use our
+	 * device as parent so suspend-resume ordering is correct
+	 */
+	if (pdata->attach_child_devices)
+		(pdata->attach_child_devices)(&pdev->dev);
+
+	hdq_priv.pdata = pdata;
+
+	return 0;
+}
+
+static int hdq_remove(struct platform_device *pdev)
+{
+	sysfs_remove_group(&pdev->dev.kobj, &hdq_attr_group);
+	return 0;
+}
+
+static struct platform_driver hdq_driver = {
+	.probe		= hdq_probe,
+	.remove		= hdq_remove,
+#ifdef CONFIG_PM
+	.suspend	= hdq_suspend,
+	.resume		= hdq_resume,
+#endif
+	.driver		= {
+		.name		= "hdq",
+	},
+};
+
+static int __init hdq_init(void)
+{
+	return platform_driver_register(&hdq_driver);
+}
+
+static void __exit hdq_exit(void)
+{
+ 	platform_driver_unregister(&hdq_driver);
+}
+
+module_init(hdq_init);
+module_exit(hdq_exit);
+
+MODULE_AUTHOR("Andy Green <andy@openmoko.com>");
+MODULE_DESCRIPTION("HDQ driver");