// SPDX-License-Identifier: GPL-2.0-only
/*
* 1-wire client/driver for the Maxim/Dallas DS2781 Stand-Alone Fuel Gauge IC
*
* Author: Renata Sayakhova <[email protected]>
*
* Based on ds2780_battery drivers
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/param.h>
#include <linux/pm.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/idr.h>
#include <linux/w1.h>
#include "../../w1/slaves/w1_ds2781.h"
/* Current unit measurement in uA for a 1 milli-ohm sense resistor */
#define DS2781_CURRENT_UNITS 1563
/* Charge unit measurement in uAh for a 1 milli-ohm sense resistor */
#define DS2781_CHARGE_UNITS 6250
/* Number of bytes in user EEPROM space */
#define DS2781_USER_EEPROM_SIZE (DS2781_EEPROM_BLOCK0_END - \
DS2781_EEPROM_BLOCK0_START + 1)
/* Number of bytes in parameter EEPROM space */
#define DS2781_PARAM_EEPROM_SIZE (DS2781_EEPROM_BLOCK1_END - \
DS2781_EEPROM_BLOCK1_START + 1)
struct ds2781_device_info {
struct device *dev;
struct power_supply *bat;
struct power_supply_desc bat_desc;
struct device *w1_dev;
};
enum current_types {
CURRENT_NOW,
CURRENT_AVG,
};
static const char model[] = "DS2781";
static const char manufacturer[] = "Maxim/Dallas";
static inline struct ds2781_device_info *
to_ds2781_device_info(struct power_supply *psy)
{
return power_supply_get_drvdata(psy);
}
static inline int ds2781_battery_io(struct ds2781_device_info *dev_info,
char *buf, int addr, size_t count, int io)
{
return w1_ds2781_io(dev_info->w1_dev, buf, addr, count, io);
}
static int w1_ds2781_read(struct ds2781_device_info *dev_info, char *buf,
int addr, size_t count)
{
return ds2781_battery_io(dev_info, buf, addr, count, 0);
}
static inline int ds2781_read8(struct ds2781_device_info *dev_info, u8 *val,
int addr)
{
return ds2781_battery_io(dev_info, val, addr, sizeof(u8), 0);
}
static int ds2781_read16(struct ds2781_device_info *dev_info, s16 *val,
int addr)
{
int ret;
u8 raw[2];
ret = ds2781_battery_io(dev_info, raw, addr, sizeof(raw), 0);
if (ret < 0)
return ret;
*val = (raw[0] << 8) | raw[1];
return 0;
}
static inline int ds2781_read_block(struct ds2781_device_info *dev_info,
u8 *val, int addr, size_t count)
{
return ds2781_battery_io(dev_info, val, addr, count, 0);
}
static inline int ds2781_write(struct ds2781_device_info *dev_info, u8 *val,
int addr, size_t count)
{
return ds2781_battery_io(dev_info, val, addr, count, 1);
}
static inline int ds2781_store_eeprom(struct device *dev, int addr)
{
return w1_ds2781_eeprom_cmd(dev, addr, W1_DS2781_COPY_DATA);
}
static inline int ds2781_recall_eeprom(struct device *dev, int addr)
{
return w1_ds2781_eeprom_cmd(dev, addr, W1_DS2781_RECALL_DATA);
}
static int ds2781_save_eeprom(struct ds2781_device_info *dev_info, int reg)
{
int ret;
ret = ds2781_store_eeprom(dev_info->w1_dev, reg);
if (ret < 0)
return ret;
ret = ds2781_recall_eeprom(dev_info->w1_dev, reg);
if (ret < 0)
return ret;
return 0;
}
/* Set sense resistor value in mhos */
static int ds2781_set_sense_register(struct ds2781_device_info *dev_info,
u8 conductance)
{
int ret;
ret = ds2781_write(dev_info, &conductance,
DS2781_RSNSP, sizeof(u8));
if (ret < 0)
return ret;
return ds2781_save_eeprom(dev_info, DS2781_RSNSP);
}
/* Get RSGAIN value from 0 to 1.999 in steps of 0.001 */
static int ds2781_get_rsgain_register(struct ds2781_device_info *dev_info,
u16 *rsgain)
{
return ds2781_read16(dev_info, rsgain, DS2781_RSGAIN_MSB);
}
/* Set RSGAIN value from 0 to 1.999 in steps of 0.001 */
static int ds2781_set_rsgain_register(struct ds2781_device_info *dev_info,
u16 rsgain)
{
int ret;
u8 raw[] = {rsgain >> 8, rsgain & 0xFF};
ret = ds2781_write(dev_info, raw,
DS2781_RSGAIN_MSB, sizeof(raw));
if (ret < 0)
return ret;
return ds2781_save_eeprom(dev_info, DS2781_RSGAIN_MSB);
}
static int ds2781_get_voltage(struct ds2781_device_info *dev_info,
int *voltage_uV)
{
int ret;
char val[2];
int voltage_raw;
ret = w1_ds2781_read(dev_info, val, DS2781_VOLT_MSB, 2 * sizeof(u8));
if (ret < 0)
return ret;
/*
* The voltage value is located in 10 bits across the voltage MSB
* and LSB registers in two's complement form
* Sign bit of the voltage value is in bit 7 of the voltage MSB register
* Bits 9 - 3 of the voltage value are in bits 6 - 0 of the
* voltage MSB register
* Bits 2 - 0 of the voltage value are in bits 7 - 5 of the
* voltage LSB register
*/
voltage_raw = (val[0] << 3) |
(val[1] >> 5);
/* DS2781 reports voltage in units of 9.76mV, but the battery class
* reports in units of uV, so convert by multiplying by 9760. */
*voltage_uV = voltage_raw * 9760;
return 0;
}
static int ds2781_get_temperature(struct ds2781_device_info *dev_info,
int *temp)
{
int ret;
char val[2];
int temp_raw;
ret = w1_ds2781_read(dev_info, val, DS2781_TEMP_MSB, 2 * sizeof(u8));
if (ret < 0)
return ret;
/*
* The temperature value is located in 10 bits across the temperature
* MSB and LSB registers in two's complement form
* Sign bit of the temperature value is in bit 7 of the temperature
* MSB register
* Bits 9 - 3 of the temperature value are in bits 6 - 0 of the
* temperature MSB register
* Bits 2 - 0 of the temperature value are in bits 7 - 5 of the
* temperature LSB register
*/
temp_raw = ((val[0]) << 3) |
(val[1] >> 5);
*temp = temp_raw + (temp_raw / 4);
return 0;
}
static int ds2781_get_current(struct ds2781_device_info *dev_info,
enum current_types type, int *current_uA)
{
int ret, sense_res;
s16 current_raw;
u8 sense_res_raw, reg_msb;
/*
* The units of measurement for current are dependent on the value of
* the sense resistor.
*/
ret = ds2781_read8(dev_info, &sense_res_raw, DS2781_RSNSP);
if (ret < 0)
return ret;
if (sense_res_raw == 0) {
dev_err(dev_info->dev, "sense resistor value is 0\n");
return -EINVAL;
}
sense_res = 1000 / sense_res_raw;
if (type == CURRENT_NOW)
reg_msb = DS2781_CURRENT_MSB;
else if (type == CURRENT_AVG)
reg_msb = DS2781_IAVG_MSB;
else
return -EINVAL;
/*
* The current value is located in 16 bits across the current MSB
* and LSB registers in two's complement form
* Sign bit of the current value is in bit 7 of the current MSB register
* Bits 14 - 8 of the current value are in bits 6 - 0 of the current
* MSB register
* Bits 7 - 0 of the current value are in bits 7 - 0 of the current
* LSB register
*/
ret = ds2781_read16(dev_info, ¤t_raw, reg_msb);
if (ret < 0)
return ret;
*current_uA = current_raw * (DS2781_CURRENT_UNITS / sense_res);
return 0;
}
static int ds2781_get_accumulated_current(struct ds2781_device_info *dev_info,
int *accumulated_current)
{
int ret, sense_res;
s16 current_raw;
u8 sense_res_raw;
/*
* The units of measurement for accumulated current are dependent on
* the value of the sense resistor.
*/
ret = ds2781_read8(dev_info, &sense_res_raw, DS2781_RSNSP);
if (ret < 0)
return ret;
if (sense_res_raw == 0) {
dev_err(dev_info->dev, "sense resistor value is 0\n");
return -EINVAL;
}
sense_res = 1000 / sense_res_raw;
/*
* The ACR value is located in 16 bits across the ACR MSB and
* LSB registers
* Bits 15 - 8 of the ACR value are in bits 7 - 0 of the ACR
* MSB register
* Bits 7 - 0 of the ACR value are in bits 7 - 0 of the ACR
* LSB register
*/
ret = ds2781_read16(dev_info, ¤t_raw, DS2781_ACR_MSB);
if (ret < 0)
return ret;
*accumulated_current = current_raw * (DS2781_CHARGE_UNITS / sense_res);
return 0;
}
static int ds2781_get_capacity(struct ds2781_device_info *dev_info,
int *capacity)
{
int ret;
u8 raw;
ret = ds2781_read8(dev_info, &raw, DS2781_RARC);
if (ret < 0)
return ret;
*capacity = raw;
return 0;
}
static int ds2781_get_status(struct ds2781_device_info *dev_info, int *status)
{
int ret, current_uA, capacity;
ret = ds2781_get_current(dev_info, CURRENT_NOW, ¤t_uA);
if (ret < 0)
return ret;
ret = ds2781_get_capacity(dev_info, &capacity);
if (ret < 0)
return ret;
if (power_supply_am_i_supplied(dev_info->bat)) {
if (capacity == 100)
*status = POWER_SUPPLY_STATUS_FULL;
else if (current_uA > 50000)
*status = POWER_SUPPLY_STATUS_CHARGING;
else
*status = POWER_SUPPLY_STATUS_NOT_CHARGING;
} else {
*status = POWER_SUPPLY_STATUS_DISCHARGING;
}
return 0;
}
static int ds2781_get_charge_now(struct ds2781_device_info *dev_info,
int *charge_now)
{
int ret;
u16 charge_raw;
/*
* The RAAC value is located in 16 bits across the RAAC MSB and
* LSB registers
* Bits 15 - 8 of the RAAC value are in bits 7 - 0 of the RAAC
* MSB register
* Bits 7 - 0 of the RAAC value are in bits 7 - 0 of the RAAC
* LSB register
*/
ret = ds2781_read16(dev_info, &charge_raw, DS2781_RAAC_MSB);
if (ret < 0)
return ret;
*charge_now = charge_raw * 1600;
return 0;
}
static int ds2781_get_control_register(struct ds2781_device_info *dev_info,
u8 *control_reg)
{
return ds2781_read8(dev_info, control_reg, DS2781_CONTROL);
}
static int ds2781_set_control_register(struct ds2781_device_info *dev_info,
u8 control_reg)
{
int ret;
ret = ds2781_write(dev_info, &control_reg,
DS2781_CONTROL, sizeof(u8));
if (ret < 0)
return ret;
return ds2781_save_eeprom(dev_info, DS2781_CONTROL);
}
static int ds2781_battery_get_property(struct power_supply *psy,
enum power_supply_property psp,
union power_supply_propval *val)
{
int ret = 0;
struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
switch (psp) {
case POWER_SUPPLY_PROP_VOLTAGE_NOW:
ret = ds2781_get_voltage(dev_info, &val->intval);
break;
case POWER_SUPPLY_PROP_TEMP:
ret = ds2781_get_temperature(dev_info, &val->intval);
break;
case POWER_SUPPLY_PROP_MODEL_NAME:
val->strval = model;
break;
case POWER_SUPPLY_PROP_MANUFACTURER:
val->strval = manufacturer;
break;
case POWER_SUPPLY_PROP_CURRENT_NOW:
ret = ds2781_get_current(dev_info, CURRENT_NOW, &val->intval);
break;
case POWER_SUPPLY_PROP_CURRENT_AVG:
ret = ds2781_get_current(dev_info, CURRENT_AVG, &val->intval);
break;
case POWER_SUPPLY_PROP_STATUS:
ret = ds2781_get_status(dev_info, &val->intval);
break;
case POWER_SUPPLY_PROP_CAPACITY:
ret = ds2781_get_capacity(dev_info, &val->intval);
break;
case POWER_SUPPLY_PROP_CHARGE_COUNTER:
ret = ds2781_get_accumulated_current(dev_info, &val->intval);
break;
case POWER_SUPPLY_PROP_CHARGE_NOW:
ret = ds2781_get_charge_now(dev_info, &val->intval);
break;
default:
ret = -EINVAL;
}
return ret;
}
static enum power_supply_property ds2781_battery_props[] = {
POWER_SUPPLY_PROP_STATUS,
POWER_SUPPLY_PROP_VOLTAGE_NOW,
POWER_SUPPLY_PROP_TEMP,
POWER_SUPPLY_PROP_MODEL_NAME,
POWER_SUPPLY_PROP_MANUFACTURER,
POWER_SUPPLY_PROP_CURRENT_NOW,
POWER_SUPPLY_PROP_CURRENT_AVG,
POWER_SUPPLY_PROP_CAPACITY,
POWER_SUPPLY_PROP_CHARGE_COUNTER,
POWER_SUPPLY_PROP_CHARGE_NOW,
};
static ssize_t ds2781_get_pmod_enabled(struct device *dev,
struct device_attribute *attr,
char *buf)
{
int ret;
u8 control_reg;
struct power_supply *psy = to_power_supply(dev);
struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
/* Get power mode */
ret = ds2781_get_control_register(dev_info, &control_reg);
if (ret < 0)
return ret;
return sysfs_emit(buf, "%d\n",
!!(control_reg & DS2781_CONTROL_PMOD));
}
static ssize_t ds2781_set_pmod_enabled(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t count)
{
int ret;
u8 control_reg, new_setting;
struct power_supply *psy = to_power_supply(dev);
struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
/* Set power mode */
ret = ds2781_get_control_register(dev_info, &control_reg);
if (ret < 0)
return ret;
ret = kstrtou8(buf, 0, &new_setting);
if (ret < 0)
return ret;
if ((new_setting != 0) && (new_setting != 1)) {
dev_err(dev_info->dev, "Invalid pmod setting (0 or 1)\n");
return -EINVAL;
}
if (new_setting)
control_reg |= DS2781_CONTROL_PMOD;
else
control_reg &= ~DS2781_CONTROL_PMOD;
ret = ds2781_set_control_register(dev_info, control_reg);
if (ret < 0)
return ret;
return count;
}
static ssize_t ds2781_get_sense_resistor_value(struct device *dev,
struct device_attribute *attr,
char *buf)
{
int ret;
u8 sense_resistor;
struct power_supply *psy = to_power_supply(dev);
struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
ret = ds2781_read8(dev_info, &sense_resistor, DS2781_RSNSP);
if (ret < 0)
return ret;
ret = sysfs_emit(buf, "%d\n", sense_resistor);
return ret;
}
static ssize_t ds2781_set_sense_resistor_value(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t count)
{
int ret;
u8 new_setting;
struct power_supply *psy = to_power_supply(dev);
struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
ret = kstrtou8(buf, 0, &new_setting);
if (ret < 0)
return ret;
ret = ds2781_set_sense_register(dev_info, new_setting);
if (ret < 0)
return ret;
return count;
}
static ssize_t ds2781_get_rsgain_setting(struct device *dev,
struct device_attribute *attr,
char *buf)
{
int ret;
u16 rsgain;
struct power_supply *psy = to_power_supply(dev);
struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
ret = ds2781_get_rsgain_register(dev_info, &rsgain);
if (ret < 0)
return ret;
return sysfs_emit(buf, "%d\n", rsgain);
}
static ssize_t ds2781_set_rsgain_setting(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t count)
{
int ret;
u16 new_setting;
struct power_supply *psy = to_power_supply(dev);
struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
ret = kstrtou16(buf, 0, &new_setting);
if (ret < 0)
return ret;
/* Gain can only be from 0 to 1.999 in steps of .001 */
if (new_setting > 1999) {
dev_err(dev_info->dev, "Invalid rsgain setting (0 - 1999)\n");
return -EINVAL;
}
ret = ds2781_set_rsgain_register(dev_info, new_setting);
if (ret < 0)
return ret;
return count;
}
static ssize_t ds2781_get_pio_pin(struct device *dev,
struct device_attribute *attr,
char *buf)
{
int ret;
u8 sfr;
struct power_supply *psy = to_power_supply(dev);
struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
ret = ds2781_read8(dev_info, &sfr, DS2781_SFR);
if (ret < 0)
return ret;
ret = sysfs_emit(buf, "%d\n", sfr & DS2781_SFR_PIOSC);
return ret;
}
static ssize_t ds2781_set_pio_pin(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t count)
{
int ret;
u8 new_setting;
struct power_supply *psy = to_power_supply(dev);
struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
ret = kstrtou8(buf, 0, &new_setting);
if (ret < 0)
return ret;
if ((new_setting != 0) && (new_setting != 1)) {
dev_err(dev_info->dev, "Invalid pio_pin setting (0 or 1)\n");
return -EINVAL;
}
ret = ds2781_write(dev_info, &new_setting,
DS2781_SFR, sizeof(u8));
if (ret < 0)
return ret;
return count;
}
static ssize_t ds2781_read_param_eeprom_bin(struct file *filp,
struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
struct device *dev = kobj_to_dev(kobj);
struct power_supply *psy = to_power_supply(dev);
struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
return ds2781_read_block(dev_info, buf,
DS2781_EEPROM_BLOCK1_START + off, count);
}
static ssize_t ds2781_write_param_eeprom_bin(struct file *filp,
struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
struct device *dev = kobj_to_dev(kobj);
struct power_supply *psy = to_power_supply(dev);
struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
int ret;
ret = ds2781_write(dev_info, buf,
DS2781_EEPROM_BLOCK1_START + off, count);
if (ret < 0)
return ret;
ret = ds2781_save_eeprom(dev_info, DS2781_EEPROM_BLOCK1_START);
if (ret < 0)
return ret;
return count;
}
static struct bin_attribute ds2781_param_eeprom_bin_attr = {
.attr = {
.name = "param_eeprom",
.mode = S_IRUGO | S_IWUSR,
},
.size = DS2781_PARAM_EEPROM_SIZE,
.read = ds2781_read_param_eeprom_bin,
.write = ds2781_write_param_eeprom_bin,
};
static ssize_t ds2781_read_user_eeprom_bin(struct file *filp,
struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
struct device *dev = kobj_to_dev(kobj);
struct power_supply *psy = to_power_supply(dev);
struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
return ds2781_read_block(dev_info, buf,
DS2781_EEPROM_BLOCK0_START + off, count);
}
static ssize_t ds2781_write_user_eeprom_bin(struct file *filp,
struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
struct device *dev = kobj_to_dev(kobj);
struct power_supply *psy = to_power_supply(dev);
struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
int ret;
ret = ds2781_write(dev_info, buf,
DS2781_EEPROM_BLOCK0_START + off, count);
if (ret < 0)
return ret;
ret = ds2781_save_eeprom(dev_info, DS2781_EEPROM_BLOCK0_START);
if (ret < 0)
return ret;
return count;
}
static struct bin_attribute ds2781_user_eeprom_bin_attr = {
.attr = {
.name = "user_eeprom",
.mode = S_IRUGO | S_IWUSR,
},
.size = DS2781_USER_EEPROM_SIZE,
.read = ds2781_read_user_eeprom_bin,
.write = ds2781_write_user_eeprom_bin,
};
static DEVICE_ATTR(pmod_enabled, S_IRUGO | S_IWUSR, ds2781_get_pmod_enabled,
ds2781_set_pmod_enabled);
static DEVICE_ATTR(sense_resistor_value, S_IRUGO | S_IWUSR,
ds2781_get_sense_resistor_value, ds2781_set_sense_resistor_value);
static DEVICE_ATTR(rsgain_setting, S_IRUGO | S_IWUSR, ds2781_get_rsgain_setting,
ds2781_set_rsgain_setting);
static DEVICE_ATTR(pio_pin, S_IRUGO | S_IWUSR, ds2781_get_pio_pin,
ds2781_set_pio_pin);
static struct attribute *ds2781_sysfs_attrs[] = {
&dev_attr_pmod_enabled.attr,
&dev_attr_sense_resistor_value.attr,
&dev_attr_rsgain_setting.attr,
&dev_attr_pio_pin.attr,
NULL
};
static struct bin_attribute *ds2781_sysfs_bin_attrs[] = {
&ds2781_param_eeprom_bin_attr,
&ds2781_user_eeprom_bin_attr,
NULL,
};
static const struct attribute_group ds2781_sysfs_group = {
.attrs = ds2781_sysfs_attrs,
.bin_attrs = ds2781_sysfs_bin_attrs,
};
static const struct attribute_group *ds2781_sysfs_groups[] = {
&ds2781_sysfs_group,
NULL,
};
static int ds2781_battery_probe(struct platform_device *pdev)
{
struct power_supply_config psy_cfg = {};
struct ds2781_device_info *dev_info;
dev_info = devm_kzalloc(&pdev->dev, sizeof(*dev_info), GFP_KERNEL);
if (!dev_info)
return -ENOMEM;
platform_set_drvdata(pdev, dev_info);
dev_info->dev = &pdev->dev;
dev_info->w1_dev = pdev->dev.parent;
dev_info->bat_desc.name = dev_name(&pdev->dev);
dev_info->bat_desc.type = POWER_SUPPLY_TYPE_BATTERY;
dev_info->bat_desc.properties = ds2781_battery_props;
dev_info->bat_desc.num_properties = ARRAY_SIZE(ds2781_battery_props);
dev_info->bat_desc.get_property = ds2781_battery_get_property;
psy_cfg.drv_data = dev_info;
psy_cfg.attr_grp = ds2781_sysfs_groups;
dev_info->bat = devm_power_supply_register(&pdev->dev,
&dev_info->bat_desc,
&psy_cfg);
if (IS_ERR(dev_info->bat)) {
dev_err(dev_info->dev, "failed to register battery\n");
return PTR_ERR(dev_info->bat);
}
return 0;
}
static struct platform_driver ds2781_battery_driver = {
.driver = {
.name = "ds2781-battery",
},
.probe = ds2781_battery_probe,
};
module_platform_driver(ds2781_battery_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Renata Sayakhova <[email protected]>");
MODULE_DESCRIPTION("Maxim/Dallas DS2781 Stand-Alone Fuel Gauge IC driver");
MODULE_ALIAS("platform:ds2781-battery");
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