[BATTERY] 1-Wire ds2760 chip battery driver

This is driver for batteries with ds2760 chip inside, found inside
almost every HP iPaq and HTC PDAs/phones.

Signed-off-by: Anton Vorontsov <cbou@mail.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

3 files changed, 479 insertions, 0 deletions

diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index 791fa0cc45fe..921456243e4b 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -28,4 +28,11 @@ config APM_POWER
           Say Y here to enable support APM status emulation using
           battery class devices.
 
+config BATTERY_DS2760
+        tristate "DS2760 battery driver (HP iPAQ & others)"
+        select W1
+        select W1_SLAVE_DS2760
+        help
+          Say Y here to enable support for batteries with ds2760 chip.
+
 endif # POWER_SUPPLY
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index 7779cebcb3ae..a978ba15f6c5 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -16,3 +16,5 @@ obj-$(CONFIG_POWER_SUPPLY)	+= power_supply.o
 
 obj-$(CONFIG_PDA_POWER)         += pda_power.o
 obj-$(CONFIG_APM_POWER)         += apm_power.o
+
+obj-$(CONFIG_BATTERY_DS2760)    += ds2760_battery.o
diff --git a/drivers/power/ds2760_battery.c b/drivers/power/ds2760_battery.c
new file mode 100644
index 000000000000..00e1ea6f1de2
--- /dev/null
+++ b/drivers/power/ds2760_battery.c
@@ -0,0 +1,470 @@
+/*
+ * Driver for batteries with DS2760 chips inside.
+ *
+ * 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/workqueue.h>
+#include <linux/pm.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+
+#include "../w1/w1.h"
+#include "../w1/slaves/w1_ds2760.h"
+
+struct ds2760_device_info {
+        struct device *dev;
+
+        /* 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_uV;                 /* units of µV */
+        int current_raw;                /* units of 0.625 mA */
+        int current_uA;                 /* units of µA */
+        int accum_current_raw;          /* units of 0.25 mAh */
+        int accum_current_uAh;          /* units of µAh */
+        int temp_raw;                   /* units of 0.125 °C */
+        int temp_C;                     /* units of 0.1 °C */
+        int rated_capacity;             /* units of µAh */
+        int rem_capacity;               /* percentage */
+        int full_active_uAh;            /* units of µAh */
+        int empty_uAh;                  /* units of µAh */
+        int life_sec;                   /* units of seconds */
+        int charge_status;              /* POWER_SUPPLY_STATUS_* */
+
+        int full_counter;
+        struct power_supply bat;
+        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 0°C, 10°C, 20°C, 30°C, 40°C
+ * 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;
+
+        /* 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) {
+                dev_warn(di->dev, "call to w1_ds2760_read failed (0x%p)\n",
+                         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 uV, so convert by multiplying by 4880. */
+        di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) |
+                          (di->raw[DS2760_VOLTAGE_LSB] >> 5);
+        di->voltage_uV = di->voltage_raw * 4880;
+
+        /* DS2760 reports current in signed units of 0.625mA, but the battery
+         * class reports in units of µA, so convert by multiplying by 625. */
+        di->current_raw =
+            (((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) |
+                          (di->raw[DS2760_CURRENT_LSB] >> 3);
+        di->current_uA = di->current_raw * 625;
+
+        /* 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_uAh = di->accum_current_raw * 250;
+
+        /* DS2760 reports temperature in signed units of 0.125°C, 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;
+
+        di->rated_capacity *= 1000; /* convert to µAh */
+
+        /* Calculate the full level at the present temperature. */
+        di->full_active_uAh = 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_uAh = battery_interpolate(scale, di->temp_C / 10);
+        di->full_active_uAh *= 1000; /* convert to µAh */
+
+        /* 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_uAh = battery_interpolate(scale, di->temp_C / 10);
+        di->empty_uAh *= 1000; /* convert to µAh */
+
+        /* From Maxim Application Note 131: remaining capacity =
+         * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */
+        di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) /
+                            (di->full_active_uAh - di->empty_uAh);
+
+        if (di->rem_capacity < 0)
+                di->rem_capacity = 0;
+        if (di->rem_capacity > 100)
+                di->rem_capacity = 100;
+
+        if (di->current_uA)
+                di->life_sec = -((di->accum_current_uAh - di->empty_uAh) *
+                                 3600L) / di->current_uA;
+        else
+                di->life_sec = 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 == POWER_SUPPLY_STATUS_UNKNOWN)
+                di->full_counter = 0;
+
+        if (power_supply_am_i_supplied(&di->bat)) {
+                if (di->current_uA > 10000) {
+                        di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
+                        di->full_counter = 0;
+                } else if (di->current_uA < -5000) {
+                        if (di->charge_status != POWER_SUPPLY_STATUS_NOT_CHARGING)
+                                dev_notice(di->dev, "not enough power to "
+                                           "charge\n");
+                        di->charge_status = POWER_SUPPLY_STATUS_NOT_CHARGING;
+                        di->full_counter = 0;
+                } else if (di->current_uA < 10000 &&
+                            di->charge_status != POWER_SUPPLY_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 = POWER_SUPPLY_STATUS_CHARGING;
+                        } else {
+                                unsigned char acr[2];
+                                int acr_val;
+
+                                /* acr is in units of 0.25 mAh */
+                                acr_val = di->full_active_uAh * 4L / 1000;
+
+                                acr[0] = acr_val >> 8;
+                                acr[1] = acr_val & 0xff;
+
+                                if (w1_ds2760_write(di->w1_dev, acr,
+                                    DS2760_CURRENT_ACCUM_MSB, 2) < 2)
+                                        dev_warn(di->dev,
+                                                 "ACR reset failed\n");
+
+                                di->charge_status = POWER_SUPPLY_STATUS_FULL;
+                        }
+                }
+        } else {
+                di->charge_status = POWER_SUPPLY_STATUS_DISCHARGING;
+                di->full_counter = 0;
+        }
+
+        if (di->charge_status != old_charge_status)
+                power_supply_changed(&di->bat);
+
+        return;
+}
+
+static void ds2760_battery_work(struct work_struct *work)
+{
+        struct ds2760_device_info *di = container_of(work,
+                struct ds2760_device_info, monitor_work.work);
+        const int interval = HZ * 60;
+
+        dev_dbg(di->dev, "%s\n", __FUNCTION__);
+
+        ds2760_battery_update_status(di);
+        queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval);
+
+        return;
+}
+
+#define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \
+                                              bat);
+
+static void ds2760_battery_external_power_changed(struct power_supply *psy)
+{
+        struct ds2760_device_info *di = to_ds2760_device_info(psy);
+
+        dev_dbg(di->dev, "%s\n", __FUNCTION__);
+
+        cancel_delayed_work(&di->monitor_work);
+        queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10);
+
+        return;
+}
+
+static int ds2760_battery_get_property(struct power_supply *psy,
+                                       enum power_supply_property psp,
+                                       union power_supply_propval *val)
+{
+        struct ds2760_device_info *di = to_ds2760_device_info(psy);
+
+        switch (psp) {
+        case POWER_SUPPLY_PROP_STATUS:
+                val->intval = di->charge_status;
+                return 0;
+        default:
+                break;
+        }
+
+        ds2760_battery_read_status(di);
+
+        switch (psp) {
+        case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+                val->intval = di->voltage_uV;
+                break;
+        case POWER_SUPPLY_PROP_CURRENT_NOW:
+                val->intval = di->current_uA;
+                break;
+        case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
+                val->intval = di->rated_capacity;
+                break;
+        case POWER_SUPPLY_PROP_CHARGE_FULL:
+                val->intval = di->full_active_uAh;
+                break;
+        case POWER_SUPPLY_PROP_CHARGE_EMPTY:
+                val->intval = di->empty_uAh;
+                break;
+        case POWER_SUPPLY_PROP_CHARGE_NOW:
+                val->intval = di->accum_current_uAh;
+                break;
+        case POWER_SUPPLY_PROP_TEMP:
+                val->intval = di->temp_C;
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        return 0;
+}
+
+static enum power_supply_property ds2760_battery_props[] = {
+        POWER_SUPPLY_PROP_STATUS,
+        POWER_SUPPLY_PROP_VOLTAGE_NOW,
+        POWER_SUPPLY_PROP_CURRENT_NOW,
+        POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
+        POWER_SUPPLY_PROP_CHARGE_FULL,
+        POWER_SUPPLY_PROP_CHARGE_EMPTY,
+        POWER_SUPPLY_PROP_CHARGE_NOW,
+        POWER_SUPPLY_PROP_TEMP,
+};
+
+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->dev         = &pdev->dev;
+        di->w1_dev           = pdev->dev.parent;
+        di->bat.name       = pdev->dev.bus_id;
+        di->bat.type       = POWER_SUPPLY_TYPE_BATTERY;
+        di->bat.properties     = ds2760_battery_props;
+        di->bat.num_properties = ARRAY_SIZE(ds2760_battery_props);
+        di->bat.get_property   = ds2760_battery_get_property;
+        di->bat.external_power_changed =
+                                  ds2760_battery_external_power_changed;
+
+        di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
+
+        retval = power_supply_register(&pdev->dev, &di->bat);
+        if (retval) {
+                dev_err(di->dev, "failed to register battery");
+                goto batt_failed;
+        }
+
+        INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work);
+        di->monitor_wqueue = create_singlethread_workqueue(pdev->dev.bus_id);
+        if (!di->monitor_wqueue) {
+                retval = -ESRCH;
+                goto workqueue_failed;
+        }
+        queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ * 1);
+
+        goto success;
+
+workqueue_failed:
+        power_supply_unregister(&di->bat);
+batt_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);
+        power_supply_unregister(&di->bat);
+
+        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 = POWER_SUPPLY_STATUS_UNKNOWN;
+
+        return 0;
+}
+
+static int ds2760_battery_resume(struct platform_device *pdev)
+{
+        struct ds2760_device_info *di = platform_get_drvdata(pdev);
+
+        di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
+        power_supply_changed(&di->bat);
+
+        cancel_delayed_work(&di->monitor_work);
+        queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ);
+
+        return 0;
+}
+
+#else
+
+#define ds2760_battery_suspend NULL
+#define ds2760_battery_resume NULL
+
+#endif /* CONFIG_PM */
+
+static struct platform_driver ds2760_battery_driver = {
+        .driver = {
+                .name = "ds2760-battery",
+        },
+        .probe    = ds2760_battery_probe,
+        .remove   = ds2760_battery_remove,
+        .suspend  = ds2760_battery_suspend,
+        .resume   = ds2760_battery_resume,
+};
+
+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);
+        return;
+}
+
+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");