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Subject[PATCH v3] ds2782_battery: add support for ds2786 battery gas gauge
Date
From: Yulia Vilensky <vilensky@compulab.co.il>

v2 changes:
* add ds278x_platform_data
* address Anton comments
v3 changes:
* use ds278x_get_temp for both ds2782 and ds2786
* update math as per Ryan comments

Signed-off-by: Yulia Vilensky <vilensky@compulab.co.il>
Signed-off-by: Mike Rapoport <mike@compulab.co.il>
---
drivers/power/Kconfig | 4 +-
drivers/power/ds2782_battery.c | 184 +++++++++++++++++++++++++++++-----------
include/linux/ds2782_battery.h | 8 ++
3 files changed, 146 insertions(+), 50 deletions(-)
create mode 100644 include/linux/ds2782_battery.h

diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index faaa9b4..d8b8a19 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -65,10 +65,10 @@ config BATTERY_DS2760
Say Y here to enable support for batteries with ds2760 chip.

config BATTERY_DS2782
- tristate "DS2782 standalone gas-gauge"
+ tristate "DS2782/DS2786 standalone gas-gauge"
depends on I2C
help
- Say Y here to enable support for the DS2782 standalone battery
+ Say Y here to enable support for the DS2782/DS2786 standalone battery
gas-gauge.

config BATTERY_PMU
diff --git a/drivers/power/ds2782_battery.c b/drivers/power/ds2782_battery.c
index 99c8997..2a651e9 100644
--- a/drivers/power/ds2782_battery.c
+++ b/drivers/power/ds2782_battery.c
@@ -5,6 +5,8 @@
*
* Author: Ryan Mallon <ryan@bluewatersys.com>
*
+ * DS2786 added by Yulia Vilensky <vilensky@compulab.co.il>
+ *
* 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.
@@ -20,12 +22,13 @@
#include <linux/idr.h>
#include <linux/power_supply.h>
#include <linux/slab.h>
+#include <linux/ds2782_battery.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
+#define DS278x_REG_VOLT_MSB 0x0c
+#define DS278x_REG_TEMP_MSB 0x0a
+#define DS278x_REG_CURRENT_MSB 0x0e

/* EEPROM Block */
#define DS2782_REG_RSNSP 0x69 /* Sense resistor value */
@@ -33,18 +36,33 @@
/* 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)
+#define DS2786_REG_RARC 0x02 /* Remaining active relative capacity */
+
+#define DS2786_CURRENT_UNITS 25
+
+struct ds278x_info;
+
+struct ds278x_battery_ops {
+ int (*get_current)(struct ds278x_info *info, int *current_uA);
+ int (*get_voltage)(struct ds278x_info *info, int *voltage_uA);
+ int (*get_capacity)(struct ds278x_info *info, int *capacity_uA);
+
+};
+
+#define to_ds278x_info(x) container_of(x, struct ds278x_info, battery)

-struct ds2782_info {
+struct ds278x_info {
struct i2c_client *client;
struct power_supply battery;
+ struct ds278x_battery_ops *ops;
int id;
+ int rsns;
};

static DEFINE_IDR(battery_id);
static DEFINE_MUTEX(battery_lock);

-static inline int ds2782_read_reg(struct ds2782_info *info, int reg, u8 *val)
+static inline int ds278x_read_reg(struct ds278x_info *info, int reg, u8 *val)
{
int ret;

@@ -58,7 +76,7 @@ static inline int ds2782_read_reg(struct ds2782_info *info, int reg, u8 *val)
return 0;
}

-static inline int ds2782_read_reg16(struct ds2782_info *info, int reg_msb,
+static inline int ds278x_read_reg16(struct ds278x_info *info, int reg_msb,
s16 *val)
{
int ret;
@@ -73,7 +91,7 @@ static inline int ds2782_read_reg16(struct ds2782_info *info, int reg_msb,
return 0;
}

-static int ds2782_get_temp(struct ds2782_info *info, int *temp)
+static int ds278x_get_temp(struct ds278x_info *info, int *temp)
{
s16 raw;
int err;
@@ -84,14 +102,14 @@ static int ds2782_get_temp(struct ds2782_info *info, int *temp)
* 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);
+ err = ds278x_read_reg16(info, DS278x_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)
+static int ds2782_get_current(struct ds278x_info *info, int *current_uA)
{
int sense_res;
int err;
@@ -102,7 +120,7 @@ static int ds2782_get_current(struct ds2782_info *info, int *current_uA)
* 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);
+ err = ds278x_read_reg(info, DS2782_REG_RSNSP, &sense_res_raw);
if (err)
return err;
if (sense_res_raw == 0) {
@@ -113,14 +131,14 @@ static int ds2782_get_current(struct ds2782_info *info, int *current_uA)

dev_dbg(&info->client->dev, "sense resistor = %d milli-ohms\n",
sense_res);
- err = ds2782_read_reg16(info, DS2782_REG_CURRENT_MSB, &raw);
+ err = ds278x_read_reg16(info, DS278x_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)
+static int ds2782_get_voltage(struct ds278x_info *info, int *voltage_uA)
{
s16 raw;
int err;
@@ -129,36 +147,77 @@ static int ds2782_get_voltage(struct ds2782_info *info, int *voltage_uA)
* 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);
+ err = ds278x_read_reg16(info, DS278x_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)
+static int ds2782_get_capacity(struct ds278x_info *info, int *capacity)
{
int err;
u8 raw;

- err = ds2782_read_reg(info, DS2782_REG_RARC, &raw);
+ err = ds278x_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)
+static int ds2786_get_current(struct ds278x_info *info, int *current_uA)
+{
+ int err;
+ s16 raw;
+
+ err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw);
+ if (err)
+ return err;
+ *current_uA = (raw / 16) * (DS2786_CURRENT_UNITS / info->rsns);
+ return 0;
+}
+
+static int ds2786_get_voltage(struct ds278x_info *info, int *voltage_uA)
+{
+ s16 raw;
+ int err;
+
+ /*
+ * Voltage is measured in units of 1.22mV. The voltage is stored as
+ * a 10-bit number plus sign, in the upper bits of a 16-bit register
+ */
+ err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw);
+ if (err)
+ return err;
+ *voltage_uA = (raw / 8) * 1220;
+ return 0;
+}
+
+static int ds2786_get_capacity(struct ds278x_info *info, int *capacity)
+{
+ int err;
+ u8 raw;
+
+ err = ds278x_read_reg(info, DS2786_REG_RARC, &raw);
+ if (err)
+ return err;
+ /* Relative capacity is displayed with resolution 0.5 % */
+ *capacity = raw/2 ;
+ return 0;
+}
+
+static int ds278x_get_status(struct ds278x_info *info, int *status)
{
int err;
int current_uA;
int capacity;

- err = ds2782_get_current(info, &current_uA);
+ err = info->ops->get_current(info, &current_uA);
if (err)
return err;

- err = ds2782_get_capacity(info, &capacity);
+ err = info->ops->get_capacity(info, &capacity);
if (err)
return err;

@@ -174,32 +233,32 @@ static int ds2782_get_status(struct ds2782_info *info, int *status)
return 0;
}

-static int ds2782_battery_get_property(struct power_supply *psy,
+static int ds278x_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);
+ struct ds278x_info *info = to_ds278x_info(psy);
int ret;

switch (prop) {
case POWER_SUPPLY_PROP_STATUS:
- ret = ds2782_get_status(info, &val->intval);
+ ret = ds278x_get_status(info, &val->intval);
break;

case POWER_SUPPLY_PROP_CAPACITY:
- ret = ds2782_get_capacity(info, &val->intval);
+ ret = info->ops->get_capacity(info, &val->intval);
break;

case POWER_SUPPLY_PROP_VOLTAGE_NOW:
- ret = ds2782_get_voltage(info, &val->intval);
+ ret = info->ops->get_voltage(info, &val->intval);
break;

case POWER_SUPPLY_PROP_CURRENT_NOW:
- ret = ds2782_get_current(info, &val->intval);
+ ret = info->ops->get_current(info, &val->intval);
break;

case POWER_SUPPLY_PROP_TEMP:
- ret = ds2782_get_temp(info, &val->intval);
+ ret = ds278x_get_temp(info, &val->intval);
break;

default:
@@ -209,7 +268,7 @@ static int ds2782_battery_get_property(struct power_supply *psy,
return ret;
}

-static enum power_supply_property ds2782_battery_props[] = {
+static enum power_supply_property ds278x_battery_props[] = {
POWER_SUPPLY_PROP_STATUS,
POWER_SUPPLY_PROP_CAPACITY,
POWER_SUPPLY_PROP_VOLTAGE_NOW,
@@ -217,18 +276,18 @@ static enum power_supply_property ds2782_battery_props[] = {
POWER_SUPPLY_PROP_TEMP,
};

-static void ds2782_power_supply_init(struct power_supply *battery)
+static void ds278x_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->properties = ds278x_battery_props;
+ battery->num_properties = ARRAY_SIZE(ds278x_battery_props);
+ battery->get_property = ds278x_battery_get_property;
battery->external_power_changed = NULL;
}

-static int ds2782_battery_remove(struct i2c_client *client)
+static int ds278x_battery_remove(struct i2c_client *client)
{
- struct ds2782_info *info = i2c_get_clientdata(client);
+ struct ds278x_info *info = i2c_get_clientdata(client);

power_supply_unregister(&info->battery);
kfree(info->battery.name);
@@ -243,13 +302,36 @@ static int ds2782_battery_remove(struct i2c_client *client)
return 0;
}

-static int ds2782_battery_probe(struct i2c_client *client,
+static struct ds278x_battery_ops ds278x_ops[] = {
+ [0] = {
+ .get_current = ds2782_get_current,
+ .get_voltage = ds2782_get_voltage,
+ .get_capacity = ds2782_get_capacity,
+ },
+ [1] = {
+ .get_current = ds2786_get_current,
+ .get_voltage = ds2786_get_voltage,
+ .get_capacity = ds2786_get_capacity,
+ }
+};
+
+static int ds278x_battery_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
- struct ds2782_info *info;
+ struct ds278x_platform_data *pdata = client->dev.platform_data;
+ struct ds278x_info *info;
int ret;
int num;

+ /*
+ * ds2786 should have the sense resistor value set
+ * in the platform data
+ */
+ if (id->driver_data == 1 && pdata == 0) {
+ dev_err(&client->dev, "missing platform data for ds2786\n");
+ return -EINVAL;
+ }
+
/* Get an ID for this battery */
ret = idr_pre_get(&battery_id, GFP_KERNEL);
if (ret == 0) {
@@ -269,15 +351,20 @@ static int ds2782_battery_probe(struct i2c_client *client,
goto fail_info;
}

- info->battery.name = kasprintf(GFP_KERNEL, "ds2782-%d", num);
+ info->battery.name = kasprintf(GFP_KERNEL, "%s-%d", client->name, num);
if (!info->battery.name) {
ret = -ENOMEM;
goto fail_name;
}

+ if (id->driver_data == 1)
+ info->rsns = pdata->rsns;
+
i2c_set_clientdata(client, info);
info->client = client;
- ds2782_power_supply_init(&info->battery);
+ info->id = num;
+ info->ops = &ds278x_ops[id->driver_data];
+ ds278x_power_supply_init(&info->battery);

ret = power_supply_register(&client->dev, &info->battery);
if (ret) {
@@ -300,31 +387,32 @@ fail_id:
return ret;
}

-static const struct i2c_device_id ds2782_id[] = {
+static const struct i2c_device_id ds278x_id[] = {
{"ds2782", 0},
+ {"ds2786", 1},
{},
};

-static struct i2c_driver ds2782_battery_driver = {
+static struct i2c_driver ds278x_battery_driver = {
.driver = {
.name = "ds2782-battery",
},
- .probe = ds2782_battery_probe,
- .remove = ds2782_battery_remove,
- .id_table = ds2782_id,
+ .probe = ds278x_battery_probe,
+ .remove = ds278x_battery_remove,
+ .id_table = ds278x_id,
};

-static int __init ds2782_init(void)
+static int __init ds278x_init(void)
{
- return i2c_add_driver(&ds2782_battery_driver);
+ return i2c_add_driver(&ds278x_battery_driver);
}
-module_init(ds2782_init);
+module_init(ds278x_init);

-static void __exit ds2782_exit(void)
+static void __exit ds278x_exit(void)
{
- i2c_del_driver(&ds2782_battery_driver);
+ i2c_del_driver(&ds278x_battery_driver);
}
-module_exit(ds2782_exit);
+module_exit(ds278x_exit);

MODULE_AUTHOR("Ryan Mallon <ryan@bluewatersys.com>");
MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauage IC driver");
diff --git a/include/linux/ds2782_battery.h b/include/linux/ds2782_battery.h
new file mode 100644
index 0000000..b4e281f
--- /dev/null
+++ b/include/linux/ds2782_battery.h
@@ -0,0 +1,8 @@
+#ifndef __LINUX_DS2782_BATTERY_H
+#define __LINUX_DS2782_BATTERY_H
+
+struct ds278x_platform_data {
+ int rsns;
+};
+
+#endif
--
1.6.6.2


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