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    Subject[PATCH 6/7] [RFC] ds2760 battery driver
    This is driver for batteries with ds2760 chip inside. Such batteries
    used in almost every HP iPaq and HTC PDAs/phones.

    ---
    drivers/battery/Kconfig | 7 +
    drivers/battery/Makefile | 1 +
    drivers/battery/ds2760_battery.c | 466 ++++++++++++++++++++++++++++++++++++++
    include/linux/ds2760_battery.h | 32 +++
    4 files changed, 506 insertions(+), 0 deletions(-)
    create mode 100644 drivers/battery/ds2760_battery.c
    create mode 100644 include/linux/ds2760_battery.h

    diff --git a/drivers/battery/Kconfig b/drivers/battery/Kconfig
    index c386593..0c14ae0 100644
    --- a/drivers/battery/Kconfig
    +++ b/drivers/battery/Kconfig
    @@ -8,4 +8,11 @@ config BATTERY
    Say Y here to enable generic battery status reporting in
    the /sys filesystem.

    +config BATTERY_DS2760
    + tristate "DS2760 battery driver (HP iPAQ & others)"
    + depends on BATTERY && W1
    + select W1_SLAVE_DS2760
    + help
    + Say Y here to enable support for batteries with ds2760 chip.
    +
    endmenu
    diff --git a/drivers/battery/Makefile b/drivers/battery/Makefile
    index a2239cb..9902513 100644
    --- a/drivers/battery/Makefile
    +++ b/drivers/battery/Makefile
    @@ -1 +1,2 @@
    obj-$(CONFIG_BATTERY) += battery.o
    +obj-$(CONFIG_BATTERY_DS2760) += ds2760_battery.o
    diff --git a/drivers/battery/ds2760_battery.c b/drivers/battery/ds2760_battery.c
    new file mode 100644
    index 0000000..a686304
    --- /dev/null
    +++ b/drivers/battery/ds2760_battery.c
    @@ -0,0 +1,466 @@
    +/*
    + * Driver for batteries with DS2760 chips inside.
    + *
    + * Copyright (c) 2007 Anton Vorontsov
    + * 2004 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
    + *
    + * Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
    + * September 2004
    + */
    +
    +#include <linux/module.h>
    +#include <linux/param.h>
    +#include <linux/jiffies.h>
    +#include <linux/workqueue.h>
    +#include <linux/pm.h>
    +#include <linux/platform_device.h>
    +#include <linux/ds2760_battery.h>
    +
    +#include "../w1/w1.h"
    +#include "../w1/slaves/w1_ds2760.h"
    +
    +struct ds2760_device_info {
    + struct battery_info *bi;
    +
    + /* DS2760 data, valid after calling ds2760_battery_read_status() */
    + unsigned long update_time; /* jiffies when data read */
    + char raw[DS2760_DATA_SIZE]; /* raw DS2760 data */
    + int voltage_raw; /* units of 4.88 mV */
    + int voltage_mV; /* units of mV */
    + int current_raw; /* units of 0.625 mA */
    + int current_mA; /* units of mA */
    + int accum_current_raw; /* units of 0.25 mAh */
    + int accum_current_mAh; /* units of mAh */
    + int temp_raw; /* units of 0.125 C */
    + int temp_C; /* units of 0.1 C */
    + int rated_capacity; /* units of mAh */
    + int rem_capacity; /* percentage */
    + int full_active_mAh; /* units of mAh */
    + int empty_mAh; /* units of mAh */
    + int life_min; /* units of minutes */
    + int charge_status; /* BATTERY_STATUS_* */
    +
    + int full_counter;
    + struct battery batt_cdev;
    + struct device *w1_dev;
    + struct workqueue_struct *monitor_wqueue;
    + struct delayed_work monitor_work;
    +};
    +
    +static unsigned int cache_time = 1000;
    +module_param(cache_time, uint, 0644);
    +MODULE_PARM_DESC(cache_time, "cache time in milliseconds");
    +
    +/* Some batteries have their rated capacity stored a N * 10 mAh, while
    + * others use an index into this table. */
    +static int rated_capacities[] = {
    + 0,
    + 920, /* Samsung */
    + 920, /* BYD */
    + 920, /* Lishen */
    + 920, /* NEC */
    + 1440, /* Samsung */
    + 1440, /* BYD */
    + 1440, /* Lishen */
    + 1440, /* NEC */
    + 2880, /* Samsung */
    + 2880, /* BYD */
    + 2880, /* Lishen */
    + 2880 /* NEC */
    +};
    +
    +/* array is level at temps 0C, 10C, 20C, 30C, 40C
    + * temp is in Celsius */
    +static int battery_interpolate(int array[], int temp)
    +{
    + int index, dt;
    +
    + if (temp <= 0)
    + return array[0];
    + if (temp >= 40)
    + return array[4];
    +
    + index = temp / 10;
    + dt = temp % 10;
    +
    + return array[index] + (((array[index + 1] - array[index]) * dt) / 10);
    +}
    +
    +static int ds2760_battery_read_status(struct ds2760_device_info *di)
    +{
    + int ret, i, start, count, scale[5];
    +
    + if (di->update_time && time_before(jiffies, di->update_time +
    + msecs_to_jiffies(cache_time)))
    + return 0;
    +
    + if (!di->w1_dev)
    + return 0;
    +
    + /* The first time we read the entire contents of SRAM/EEPROM,
    + * but after that we just read the interesting bits that change. */
    + if (di->update_time == 0) {
    + start = 0;
    + count = DS2760_DATA_SIZE;
    + }
    + else {
    + start = DS2760_VOLTAGE_MSB;
    + count = DS2760_TEMP_LSB - start + 1;
    + }
    +
    + ret = w1_ds2760_read(di->w1_dev, di->raw + start, start, count);
    + if (ret != count) {
    + printk("call to w1_ds2760_read failed (0x%08x)\n",
    + (unsigned int)di->w1_dev);
    + return 1;
    + }
    +
    + di->update_time = jiffies;
    +
    + /* DS2760 reports voltage in units of 4.88mV, but the battery class
    + * reports in units of mV, so convert by multiplying by 4.875.
    + * We approximate because integer math is cheap, and close enough. */
    + di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) |
    + (di->raw[DS2760_VOLTAGE_LSB] >> 5);
    + di->voltage_mV = (di->voltage_raw * 5) - (di->voltage_raw / 8);
    +
    + /* DS2760 reports current in signed units of 0.625mA, but the battery
    + * class reports in units of mA, so convert by multiplying by 0.625. */
    + di->current_raw =
    + (((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) |
    + (di->raw[DS2760_CURRENT_LSB] >> 3);
    + di->current_mA = (di->current_raw / 2) + (di->current_raw / 8);
    +
    + /* DS2760 reports accumulated current in signed units of 0.25mAh. */
    + di->accum_current_raw =
    + (((signed char)di->raw[DS2760_CURRENT_ACCUM_MSB]) << 8) |
    + di->raw[DS2760_CURRENT_ACCUM_LSB];
    + di->accum_current_mAh = di->accum_current_raw / 4;
    +
    + /* DS2760 reports temperature in signed units of 0.125C, but the
    + * battery class reports in units of 1/10 C, so we convert by
    + * multiplying by .125 * 10 = 1.25. */
    + di->temp_raw = (((signed char)di->raw[DS2760_TEMP_MSB]) << 3) |
    + (di->raw[DS2760_TEMP_LSB] >> 5);
    + di->temp_C = di->temp_raw + (di->temp_raw / 4);
    +
    + /* At least some battery monitors (e.g. HP iPAQ) store the battery's
    + * maximum rated capacity. */
    + if (di->raw[DS2760_RATED_CAPACITY] < ARRAY_SIZE(rated_capacities))
    + di->rated_capacity = rated_capacities[
    + (unsigned int)di->raw[DS2760_RATED_CAPACITY]];
    + else
    + di->rated_capacity = di->raw[DS2760_RATED_CAPACITY] * 10;
    +
    + /* Calculate the full level at the present temperature. */
    + di->full_active_mAh = di->raw[DS2760_ACTIVE_FULL] << 8 |
    + di->raw[DS2760_ACTIVE_FULL + 1];
    +
    + scale[0] = di->raw[DS2760_ACTIVE_FULL] << 8 |
    + di->raw[DS2760_ACTIVE_FULL + 1];
    + for (i = 1; i < 5; i++)
    + scale[i] = scale[i - 1] + di->raw[DS2760_ACTIVE_FULL + 2 + i];
    +
    + di->full_active_mAh = battery_interpolate(scale, di->temp_C / 10);
    +
    + /* Calculate the empty level at the present temperature. */
    + scale[4] = di->raw[DS2760_ACTIVE_EMPTY + 4];
    + for (i = 3; i >= 0; i--)
    + scale[i] = scale[i + 1] + di->raw[DS2760_ACTIVE_EMPTY + i];
    +
    + di->empty_mAh = battery_interpolate(scale, di->temp_C / 10);
    +
    + /* From Maxim Application Note 131: remaining capacity =
    + * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */
    + di->rem_capacity = ((di->accum_current_mAh - di->empty_mAh) * 100) /
    + (di->full_active_mAh - di->empty_mAh);
    +
    + if (di->rem_capacity < 0)
    + di->rem_capacity = 0;
    + if (di->rem_capacity > 100)
    + di->rem_capacity = 100;
    +
    + if (di->current_mA)
    + di->life_min = -((di->accum_current_mAh - di->empty_mAh) *
    + 60) / di->current_mA;
    + else
    + di->life_min = 0;
    +
    + return 0;
    +}
    +
    +static void ds2760_battery_update_status(struct ds2760_device_info *di)
    +{
    + int old_charge_status = di->charge_status;
    +
    + ds2760_battery_read_status(di);
    +
    + if (di->charge_status == BATTERY_STATUS_UNKNOWN)
    + di->full_counter = 0;
    +
    + if (battery_is_external_power_supplied(&di->batt_cdev)) {
    + if (di->current_mA > 10) {
    + di->charge_status = BATTERY_STATUS_CHARGING;
    + di->full_counter = 0;
    + }
    + else if (di->current_mA < -5) {
    + if (di->charge_status != BATTERY_STATUS_DISCHARGING)
    + printk(KERN_WARNING "%s: not enough power to "
    + "charge\n", di->bi->name);
    + di->charge_status = BATTERY_STATUS_DISCHARGING;
    + di->full_counter = 0;
    + }
    + else if (di->current_mA < 10 &&
    + di->charge_status != BATTERY_STATUS_FULL) {
    +
    + /* Don't consider the battery to be full unless
    + * we've seen the current < 10 mA at least two
    + * consecutive times. */
    +
    + di->full_counter++;
    +
    + if (di->full_counter < 2)
    + di->charge_status = BATTERY_STATUS_CHARGING;
    + else {
    + unsigned char acr[2];
    +
    + acr[0] = (di->full_active_mAh * 4) >> 8;
    + acr[1] = (di->full_active_mAh * 4) & 0xff;
    +
    + if (w1_ds2760_write(di->w1_dev, acr,
    + DS2760_CURRENT_ACCUM_MSB, 2) < 2)
    + printk(KERN_ERR "ACR reset failed\n");
    + di->charge_status = BATTERY_STATUS_FULL;
    + }
    + }
    + }
    + else {
    + di->charge_status = BATTERY_STATUS_DISCHARGING;
    + di->full_counter = 0;
    + }
    +
    + if (di->charge_status != old_charge_status)
    + battery_status_changed(&di->batt_cdev);
    +
    + return;
    +}
    +
    +static int ds2760_battery_match_callback(struct device *dev, void *data)
    +{
    + struct w1_slave *sl;
    +
    + if (!(dev->driver && dev->driver->name &&
    + (strcmp(dev->driver->name, "w1_slave_driver") == 0)))
    + return 0;
    +
    + sl = container_of(dev, struct w1_slave, dev);
    +
    + /* DS2760 w1 slave device names begin with the family number 0x30. */
    + if (strncmp(sl->name, "30-", 3) != 0)
    + return 0;
    +
    + return 1;
    +}
    +
    +static void ds2760_battery_work(struct work_struct *work)
    +{
    + struct ds2760_device_info *di = container_of(work,
    + struct ds2760_device_info, monitor_work.work);
    + struct bus_type *bus;
    + int interval = HZ * 60;
    +
    + if (!di->w1_dev) {
    + /* Get the battery w1 slave device. */
    + bus = find_bus("w1");
    + if (bus)
    + di->w1_dev = bus_find_device(bus, NULL, NULL,
    + ds2760_battery_match_callback);
    +
    + if (!di->w1_dev) {
    + pr_debug("%s: no dev found\n", __FUNCTION__);
    + interval = HZ * 10;
    + goto again_please;
    + }
    + pr_debug("%s: dev found\n", __FUNCTION__);
    + }
    +
    + ds2760_battery_update_status(di);
    +
    +again_please:
    + queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval);
    + return;
    +}
    +
    +#define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \
    + batt_cdev);
    +
    +static void ds2760_battery_external_power_changed(struct battery *bat)
    +{
    + struct ds2760_device_info *di = to_ds2760_device_info(bat);
    + cancel_delayed_work(&di->monitor_work);
    + queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10);
    + return;
    +}
    +
    +#define ds2760_cdev_prop(x,y,z) \
    + static int ds2760_battery_get_##y(struct battery *bat) \
    + { \
    + struct ds2760_device_info *di = to_ds2760_device_info(bat); \
    + if (x) \
    + ds2760_battery_read_status(di); \
    + return di->z; \
    + }
    +
    +ds2760_cdev_prop(0, max_voltage, bi->max_voltage);
    +ds2760_cdev_prop(0, min_voltage, bi->min_voltage);
    +ds2760_cdev_prop(1, voltage, voltage_mV);
    +ds2760_cdev_prop(0, max_current, bi->max_current);
    +ds2760_cdev_prop(0, min_current, bi->min_current);
    +ds2760_cdev_prop(1, current, current_mA);
    +ds2760_cdev_prop(1, max_capacity, full_active_mAh);
    +ds2760_cdev_prop(1, min_capacity, empty_mAh);
    +ds2760_cdev_prop(1, capacity, accum_current_mAh);
    +ds2760_cdev_prop(1, temp, temp_C);
    +ds2760_cdev_prop(0, status, charge_status);
    +
    +static int ds2760_battery_probe(struct platform_device *pdev)
    +{
    + int retval = 0;
    + struct ds2760_device_info *di;
    + struct ds2760_platform_data *pdata;
    +
    + 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->bi = &pdata->battery_info;
    +
    + di->batt_cdev.name = di->bi->name;
    + di->batt_cdev.get_voltage = ds2760_battery_get_voltage;
    + di->batt_cdev.get_min_voltage = ds2760_battery_get_min_voltage;
    + di->batt_cdev.get_max_voltage = ds2760_battery_get_max_voltage;
    + di->batt_cdev.get_current = ds2760_battery_get_current;
    + di->batt_cdev.get_min_current = ds2760_battery_get_min_current;
    + di->batt_cdev.get_max_current = ds2760_battery_get_max_current;
    + di->batt_cdev.get_capacity = ds2760_battery_get_capacity;
    + di->batt_cdev.get_min_capacity = ds2760_battery_get_min_capacity;
    + di->batt_cdev.get_max_capacity = ds2760_battery_get_max_capacity;
    + di->batt_cdev.get_temp = ds2760_battery_get_temp;
    + di->batt_cdev.get_status = ds2760_battery_get_status;
    + di->batt_cdev.external_power_changed =
    + ds2760_battery_external_power_changed;
    +
    + di->charge_status = BATTERY_STATUS_UNKNOWN;
    +
    + retval = battery_register(&pdev->dev, &di->batt_cdev);
    + if (retval) {
    + printk(KERN_ERR "Failed to register class dev for %s",
    + pdev->name);
    + goto batt_cdev_failed;
    + }
    +
    + INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work);
    + di->monitor_wqueue = create_singlethread_workqueue("ds2760_mon");
    + if (!di->monitor_wqueue) {
    + retval = -ESRCH;
    + goto workqueue_failed;
    + }
    + queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ * 1);
    +
    + goto success;
    +
    +workqueue_failed:
    + battery_unregister(&di->batt_cdev);
    +batt_cdev_failed:
    + kfree(di);
    +di_alloc_failed:
    +success:
    + return retval;
    +}
    +
    +static int ds2760_battery_remove(struct platform_device *pdev)
    +{
    + struct ds2760_device_info *di = platform_get_drvdata(pdev);
    +
    + cancel_rearming_delayed_workqueue(di->monitor_wqueue,
    + &di->monitor_work);
    + destroy_workqueue(di->monitor_wqueue);
    + battery_unregister(&di->batt_cdev);
    + if (di->w1_dev)
    + put_device(di->w1_dev);
    +
    + return 0;
    +}
    +
    +#ifdef CONFIG_PM
    +static int ds2760_battery_suspend(struct platform_device *pdev,
    + pm_message_t state)
    +{
    + struct ds2760_device_info *di = platform_get_drvdata(pdev);
    +
    + di->charge_status = BATTERY_STATUS_UNKNOWN;
    + battery_status_changed(&di->batt_cdev);
    +
    + return 0;
    +}
    +
    +static int ds2760_battery_resume(struct platform_device *pdev)
    +{
    + struct ds2760_device_info *di = platform_get_drvdata(pdev);
    +
    + di->charge_status = BATTERY_STATUS_UNKNOWN;
    + battery_status_changed(&di->batt_cdev);
    +
    + cancel_delayed_work(&di->monitor_work);
    + queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ);
    +
    + return 0;
    +}
    +#endif /* CONFIG_PM */
    +
    +static struct platform_driver ds2760_battery_driver = {
    + .driver = {
    + .name = "ds2760-battery",
    + },
    + .probe = ds2760_battery_probe,
    + .remove = ds2760_battery_remove,
    + #ifdef CONFIG_PM
    + .suspend = ds2760_battery_suspend,
    + .resume = ds2760_battery_resume,
    + #endif
    +};
    +
    +static int __init ds2760_battery_init(void)
    +{
    + return platform_driver_register(&ds2760_battery_driver);
    +}
    +
    +static void __exit ds2760_battery_exit(void)
    +{
    + platform_driver_unregister(&ds2760_battery_driver);
    +}
    +
    +module_init(ds2760_battery_init);
    +module_exit(ds2760_battery_exit);
    +
    +MODULE_LICENSE("GPL");
    +MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
    + "Matt Reimer <mreimer@vpop.net>, "
    + "Anton Vorontsov <cbou@mail.ru>");
    +MODULE_DESCRIPTION("ds2760 battery driver");
    diff --git a/include/linux/ds2760_battery.h b/include/linux/ds2760_battery.h
    new file mode 100644
    index 0000000..2937a54
    --- /dev/null
    +++ b/include/linux/ds2760_battery.h
    @@ -0,0 +1,32 @@
    +/*
    + * Driver for batteries with DS2760 chips inside.
    + *
    + * Copyright (c) 2007 Anton Vorontsov
    + * 2004 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
    + *
    + * Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
    + * September 2004
    + */
    +
    +#ifndef __DS2760_BATTERY__
    +#define __DS2760_BATTERY__
    +
    +#include <linux/battery.h>
    +
    +struct ds2760_platform_data {
    + /* Battery information and characteristics. */
    + struct battery_info battery_info;
    +};
    +
    +#endif
    --
    1.5.0.5-dirty
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