Re: [PATCH] ds2782 battery gas gauge driver

From: Anton Vorontsov
Date: Wed Jun 24 2009 - 10:13:31 EST

On Wed, Jun 24, 2009 at 11:55:04AM +1200, Ryan Mallon wrote:
> Ryan Mallon wrote:
> >
> > Updated patch below.
> >
> >
> Any further comments on this? I got an IP blocked bounce on Anton's
> cbou@xxxxxxx, so have CC'ed his other address here.

The driver looks OK (modulo some cosmetic issues, but don't
worry, I'll fix them myself).

I'm about to send a pull request for battery tree, so I'll
apply the patch after that (targeting 2.6.31, of course).

Thanks for the driver!

> > ---
> > Add support for the DS2782 stand-alone I2C gas-gauge
> >
> > Signed-off-by: Ryan Mallon <ryan@xxxxxxxxxxxxxxxx>
> > ---
> >
> > diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
> > index 33da112..b9c818f 100644
> > --- a/drivers/power/Kconfig
> > +++ b/drivers/power/Kconfig
> > @@ -43,6 +43,13 @@ config BATTERY_DS2760
> > help
> > Say Y here to enable support for batteries with ds2760 chip.
> >
> > +config BATTERY_DS2782
> > + tristate "DS2782 standalone gas-gauge"
> > + depends on I2C
> > + help
> > + Say Y here to enable support for the DS2782 standalone battery
> > + gas-gauge.
> > +
> > config BATTERY_PMU
> > tristate "Apple PMU battery"
> > depends on PPC32 && ADB_PMU
> > diff --git a/drivers/power/Makefile b/drivers/power/Makefile
> > index 2fcf41d..ad1ac61 100644
> > --- a/drivers/power/Makefile
> > +++ b/drivers/power/Makefile
> > @@ -19,6 +19,7 @@ obj-$(CONFIG_APM_POWER) += apm_power.o
> > obj-$(CONFIG_WM8350_POWER) += wm8350_power.o
> >
> > obj-$(CONFIG_BATTERY_DS2760) += ds2760_battery.o
> > +obj-$(CONFIG_BATTERY_DS2782) += ds2782_battery.o
> > obj-$(CONFIG_BATTERY_PMU) += pmu_battery.o
> > obj-$(CONFIG_BATTERY_OLPC) += olpc_battery.o
> > obj-$(CONFIG_BATTERY_TOSA) += tosa_battery.o
> > diff --git a/drivers/power/ds2782_battery.c b/drivers/power/ds2782_battery.c
> > new file mode 100644
> > index 0000000..cfd4d28
> > --- /dev/null
> > +++ b/drivers/power/ds2782_battery.c
> > @@ -0,0 +1,321 @@
> > +/*
> > + * drivers/power/ds2782_battery.c
> > + *
> > + * I2C client/driver for the Maxim/Dallas DS2782 Stand-Alone Fuel Gauge IC
> > + *
> > + * Copyright (C) 2009 Bluewater Systems Ltd
> > + * Author: Ryan Mallon <ryan@xxxxxxxxxxxxxxxx>
> > + *
> > + * 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/module.h>
> > +#include <linux/i2c.h>
> > +#include <linux/idr.h>
> > +#include <linux/power_supply.h>
> > +
> > +#define DS2782_REG_RARC 0x06 /* Remaining active relative capacity */
> > +
> > +#define DS2782_REG_VOLT_MSB 0x0c
> > +#define DS2782_REG_TEMP_MSB 0x0a
> > +#define DS2782_REG_CURRENT_MSB 0x0e
> > +
> > +/* EEPROM Block */
> > +#define DS2782_REG_RSNSP 0x69 /* Sense resistor value */
> > +
> > +/* Current unit measurement in uA for a 1 milli-ohm sense resistor */
> > +#define DS2782_CURRENT_UNITS 1563
> > +
> > +#define to_ds2782_info(x) container_of(x, struct ds2782_info, battery)
> > +
> > +struct ds2782_info {
> > + struct i2c_client *client;
> > + struct power_supply battery;
> > + int id;
> > +};
> > +
> > +static DEFINE_IDR(battery_id);
> > +static DEFINE_MUTEX(battery_lock);
> > +
> > +static inline int ds2782_read_reg(struct ds2782_info *info, int reg, u8 *val)
> > +{
> > + int ret = i2c_smbus_read_byte_data(info->client, reg);
> > + if (ret < 0) {
> > + dev_err(&info->client->dev, "register read failed\n");
> > + return ret;
> > + }
> > +
> > + *val = ret;
> > + return 0;
> > +}
> > +
> > +static inline int ds2782_read_reg16(struct ds2782_info *info, int reg_msb,
> > + s16 *val)
> > +{
> > + int ret = swab16(i2c_smbus_read_word_data(info->client, reg_msb));
> > + if (ret < 0) {
> > + dev_err(&info->client->dev, "register read failed\n");
> > + return ret;
> > + }
> > +
> > + *val = ret;
> > + return 0;
> > +}
> > +
> > +static int ds2782_get_temp(struct ds2782_info *info, int *temp)
> > +{
> > + s16 raw;
> > + int err;
> > +
> > + /*
> > + * Temperature is measured in units of 0.125 degrees celcius, the
> > + * power_supply class measures temperature in tenths of degrees
> > + * celsius. The temperature value is stored as a 10 bit number, plus
> > + * sign in the upper bits of a 16 bit register.
> > + */
> > + err = ds2782_read_reg16(info, DS2782_REG_TEMP_MSB, &raw);
> > + if (err)
> > + return err;
> > + *temp = ((raw / 32) * 125) / 100;
> > + return 0;
> > +}
> > +
> > +static int ds2782_get_current(struct ds2782_info *info, int *current_uA)
> > +{
> > + int sense_res, err;
> > + u8 sense_res_raw;
> > + s16 raw;
> > +
> > + /*
> > + * The units of measurement for current are dependent on the value of
> > + * the sense resistor.
> > + */
> > + err = ds2782_read_reg(info, DS2782_REG_RSNSP, &sense_res_raw);
> > + if (err)
> > + return err;
> > + if (sense_res_raw == 0) {
> > + dev_err(&info->client->dev, "sense resistor value is 0\n");
> > + return -ENXIO;
> > + }
> > + sense_res = 1000 / sense_res_raw;
> > +
> > + dev_dbg(&info->client->dev, "sense resistor = %d milli-ohms\n",
> > + sense_res);
> > + err = ds2782_read_reg16(info, DS2782_REG_CURRENT_MSB, &raw);
> > + if (err)
> > + return err;
> > + *current_uA = raw * (DS2782_CURRENT_UNITS / sense_res);
> > + return 0;
> > +}
> > +
> > +static int ds2782_get_voltage(struct ds2782_info *info, int *voltage_uA)
> > +{
> > + s16 raw;
> > + int err;
> > +
> > + /*
> > + * Voltage is measured in units of 4.88mV. The voltage is stored as
> > + * a 10-bit number plus sign, in the upper bits of a 16-bit register
> > + */
> > + err = ds2782_read_reg16(info, DS2782_REG_VOLT_MSB, &raw);
> > + if (err)
> > + return err;
> > + *voltage_uA = (raw / 32) * 4800;
> > + return 0;
> > +}
> > +
> > +static int ds2782_get_capacity(struct ds2782_info *info, int *capacity)
> > +{
> > + int err;
> > + u8 raw;
> > +
> > + err = ds2782_read_reg(info, DS2782_REG_RARC, &raw);
> > + if (err)
> > + return err;
> > + *capacity = raw;
> > + return raw;
> > +}
> > +
> > +static int ds2782_get_status(struct ds2782_info *info, int *status)
> > +{
> > + int err, current_uA, capacity;
> > +
> > + err = ds2782_get_current(info, &current_uA);
> > + if (err)
> > + return err;
> > +
> > + err = ds2782_get_capacity(info, &capacity);
> > + if (err)
> > + return err;
> > +
> > + if (capacity == 100)
> > + *status = POWER_SUPPLY_STATUS_FULL;
> > + else if (current_uA == 0)
> > + *status = POWER_SUPPLY_STATUS_NOT_CHARGING;
> > + else if (current_uA < 0)
> > + *status = POWER_SUPPLY_STATUS_DISCHARGING;
> > + else
> > + *status = POWER_SUPPLY_STATUS_CHARGING;
> > +
> > + return 0;
> > +}
> > +
> > +static int ds2782_battery_get_property(struct power_supply *psy,
> > + enum power_supply_property prop,
> > + union power_supply_propval *val)
> > +{
> > + struct ds2782_info *info = to_ds2782_info(psy);
> > + int ret;
> > +
> > + switch (prop) {
> > + case POWER_SUPPLY_PROP_STATUS:
> > + ret = ds2782_get_status(info, &val->intval);
> > + break;
> > +
> > + case POWER_SUPPLY_PROP_CAPACITY:
> > + ret = ds2782_get_capacity(info, &val->intval);
> > + break;
> > +
> > + case POWER_SUPPLY_PROP_VOLTAGE_NOW:
> > + ret = ds2782_get_voltage(info, &val->intval);
> > + break;
> > +
> > + case POWER_SUPPLY_PROP_CURRENT_NOW:
> > + ret = ds2782_get_current(info, &val->intval);
> > + break;
> > +
> > + case POWER_SUPPLY_PROP_TEMP:
> > + ret = ds2782_get_temp(info, &val->intval);
> > + break;
> > +
> > + default:
> > + ret = -EINVAL;
> > + }
> > +
> > + return ret;
> > +}
> > +
> > +static enum power_supply_property ds2782_battery_props[] = {
> > + POWER_SUPPLY_PROP_STATUS,
> > + POWER_SUPPLY_PROP_CAPACITY,
> > + POWER_SUPPLY_PROP_VOLTAGE_NOW,
> > + POWER_SUPPLY_PROP_CURRENT_NOW,
> > + POWER_SUPPLY_PROP_TEMP,
> > +};
> > +
> > +static void ds2782_power_supply_init(struct power_supply *battery)
> > +{
> > + battery->type = POWER_SUPPLY_TYPE_BATTERY;
> > + battery->properties = ds2782_battery_props;
> > + battery->num_properties = ARRAY_SIZE(ds2782_battery_props);
> > + battery->get_property = ds2782_battery_get_property;
> > + battery->external_power_changed = NULL;
> > +}
> > +
> > +static int ds2782_battery_remove(struct i2c_client *client)
> > +{
> > + struct ds2782_info *info = i2c_get_clientdata(client);
> > +
> > + power_supply_unregister(&info->battery);
> > + kfree(info->battery.name);
> > +
> > + mutex_lock(&battery_lock);
> > + idr_remove(&battery_id, info->id);
> > + mutex_unlock(&battery_lock);
> > +
> > + i2c_set_clientdata(client, info);
> > +
> > + kfree(info);
> > + return 0;
> > +}
> > +
> > +static int ds2782_battery_probe(struct i2c_client *client,
> > + const struct i2c_device_id *id)
> > +{
> > + struct ds2782_info *info;
> > + int ret, num;
> > +
> > + /* Get an ID for this battery */
> > + ret = idr_pre_get(&battery_id, GFP_KERNEL);
> > + if (ret == 0) {
> > + ret = -ENOMEM;
> > + goto fail_id;
> > + }
> > +
> > + mutex_lock(&battery_lock);
> > + ret = idr_get_new(&battery_id, client, &num);
> > + mutex_unlock(&battery_lock);
> > + if (ret < 0)
> > + goto fail_id;
> > +
> > + info = kzalloc(sizeof(struct ds2782_info), GFP_KERNEL);
> > + if (!info) {
> > + ret = -ENOMEM;
> > + goto fail_info;
> > + }
> > +
> > + info->battery.name = kasprintf(GFP_KERNEL, "ds2782-%d", num);
> > + if (!info->battery.name) {
> > + ret = -ENOMEM;
> > + goto fail_name;
> > + }
> > +
> > + i2c_set_clientdata(client, info);
> > + info->client = client;
> > + ds2782_power_supply_init(&info->battery);
> > +
> > + ret = power_supply_register(&client->dev, &info->battery);
> > + if (ret) {
> > + dev_err(&client->dev, "failed to register battery\n");
> > + goto fail_register;
> > + }
> > +
> > + return 0;
> > +
> > +fail_register:
> > + kfree(info->battery.name);
> > +fail_name:
> > + i2c_set_clientdata(client, info);
> > + kfree(info);
> > +fail_info:
> > + mutex_lock(&battery_lock);
> > + idr_remove(&battery_id, num);
> > + mutex_unlock(&battery_lock);
> > +fail_id:
> > + return ret;
> > +}
> > +
> > +static const struct i2c_device_id ds2782_id[] = {
> > + {"ds2782", 0},
> > + {},
> > +};
> > +
> > +static struct i2c_driver ds2782_battery_driver = {
> > + .driver = {
> > + .name = "ds2782-battery",
> > + },
> > + .probe = ds2782_battery_probe,
> > + .remove = ds2782_battery_remove,
> > + .id_table = ds2782_id,
> > +};
> > +
> > +static int __init ds2782_init(void)
> > +{
> > + return i2c_add_driver(&ds2782_battery_driver);
> > +}
> > +
> > +static void __exit ds2782_exit(void)
> > +{
> > + i2c_del_driver(&ds2782_battery_driver);
> > +}
> > +
> > +module_init(ds2782_init);
> > +module_exit(ds2782_exit);
> > +
> > +MODULE_AUTHOR("Ryan Mallon <ryan@xxxxxxxxxxxxxxxx>");
> > +MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauage IC driver");
> > +MODULE_LICENSE("GPL");
> >
> >
> >

--
Anton Vorontsov
email: cbouatmailru@xxxxxxxxx
irc://irc.freenode.net/bd2
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