Re: [PATCH] ds2782 battery gas gauge driver

From: Ryan Mallon
Date: Tue Jun 23 2009 - 19:53:08 EST

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.
> ---
> 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");
>
>
>


--
Bluewater Systems Ltd - ARM Technology Solution Centre

Ryan Mallon Unit 5, Amuri Park
Phone: +64 3 3779127 404 Barbadoes St
Fax: +64 3 3779135 PO Box 13 889
Email: ryan@xxxxxxxxxxxxxxxx Christchurch, 8013
Web: http://www.bluewatersys.com New Zealand
Freecall Australia 1800 148 751 USA 1800 261 2934

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