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Subject[PATCH 1/1] power supply: add driver for TI BQ20Z75 gas gauge IC
Date
From: Rhyland Klein <rklein@nvidia.com>

this driver depends on I2C and uses SMBUS for communication with the host.

Signed-off-by: Rhyland Klein <rklein@nvidia.com>
---
drivers/power/Kconfig | 7 +
drivers/power/Makefile | 1 +
drivers/power/bq20z75.c | 403 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 411 insertions(+), 0 deletions(-)
create mode 100644 drivers/power/bq20z75.c
diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index 8e9ba17..c72e628 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -142,4 +142,11 @@ config CHARGER_PCF50633
help
Say Y to include support for NXP PCF50633 Main Battery Charger.

+config BQ20Z75_GASGAUGE
+ tristate "TI BQ20Z75 GAS GAUGE"
+ depends on I2C
+ help
+ Say Y to include support for TI BQ20Z75 SBS-compliant
+ gas gauge and protection IC.
+
endif # POWER_SUPPLY
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index 0005080..98abc31 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -34,3 +34,4 @@ obj-$(CONFIG_BATTERY_DA9030) += da9030_battery.o
obj-$(CONFIG_BATTERY_MAX17040) += max17040_battery.o
obj-$(CONFIG_BATTERY_Z2) += z2_battery.o
obj-$(CONFIG_CHARGER_PCF50633) += pcf50633-charger.o
+obj-$(CONFIG_BQ20Z75_GASGAUGE) += bq20z75.o
diff --git a/drivers/power/bq20z75.c b/drivers/power/bq20z75.c
new file mode 100644
index 0000000..4eb6638
--- /dev/null
+++ b/drivers/power/bq20z75.c
@@ -0,0 +1,403 @@
+/*
+ * drivers/power/bq20z75.c
+ *
+ * Gas Gauge driver for TI's BQ20Z75
+ *
+ * Copyright (c) 2010, NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/debugfs.h>
+#include <linux/power_supply.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+
+enum {
+ REG_MANUFACTURER_DATA,
+ REG_TEMPERATURE,
+ REG_VOLTAGE,
+ REG_CURRENT,
+ REG_CAPACITY,
+ REG_TIME_TO_EMPTY,
+ REG_TIME_TO_FULL,
+ REG_STATUS,
+ REG_CYCLE_COUNT,
+ REG_SERIAL_NUMBER,
+ REG_MAX
+};
+
+#define BATTERY_MANUFACTURER_SIZE 12
+#define BATTERY_NAME_SIZE 8
+
+/* manufacturer access defines */
+#define MANUFACTURER_ACCESS_STATUS 0x0006
+#define MANUFACTURER_ACCESS_SLEEP 0x0011
+
+/* battery status value bits */
+#define BATTERY_CHARGING 0x40
+#define BATTERY_FULL_CHARGED 0x20
+#define BATTERY_FULL_DISCHARGED 0x10
+
+#define BQ20Z75_DATA(_psp, _addr, _min_value, _max_value) { \
+ .psp = _psp, \
+ .addr = _addr, \
+ .min_value = _min_value, \
+ .max_value = _max_value, \
+}
+
+static struct bq20z75_device_data {
+ enum power_supply_property psp;
+ u8 addr;
+ int min_value;
+ int max_value;
+} bq20z75_data[] = {
+ [REG_MANUFACTURER_DATA] =
+ BQ20Z75_DATA(POWER_SUPPLY_PROP_PRESENT, 0x00, 0, 65535),
+ [REG_TEMPERATURE] =
+ BQ20Z75_DATA(POWER_SUPPLY_PROP_TEMP, 0x08, 0, 65535),
+ [REG_VOLTAGE] =
+ BQ20Z75_DATA(POWER_SUPPLY_PROP_VOLTAGE_NOW, 0x09, 0, 20000),
+ [REG_CURRENT] =
+ BQ20Z75_DATA(POWER_SUPPLY_PROP_CURRENT_NOW, 0x0A, -32768, \
+ 32767),
+ [REG_CAPACITY] =
+ BQ20Z75_DATA(POWER_SUPPLY_PROP_CAPACITY, 0x0e, 0, 100),
+ [REG_TIME_TO_EMPTY] =
+ BQ20Z75_DATA(POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG, 0x12, 0, \
+ 65535),
+ [REG_TIME_TO_FULL] =
+ BQ20Z75_DATA(POWER_SUPPLY_PROP_TIME_TO_FULL_AVG, 0x13, 0, \
+ 65535),
+ [REG_STATUS] =
+ BQ20Z75_DATA(POWER_SUPPLY_PROP_STATUS, 0x16, 0, 65535),
+ [REG_CYCLE_COUNT] =
+ BQ20Z75_DATA(POWER_SUPPLY_PROP_CYCLE_COUNT, 0x17, 0, 65535),
+ [REG_SERIAL_NUMBER] =
+ BQ20Z75_DATA(POWER_SUPPLY_PROP_SERIAL_NUMBER, 0x1C, 0, 65535),
+};
+
+static enum power_supply_property bq20z75_properties[] = {
+ POWER_SUPPLY_PROP_STATUS,
+ POWER_SUPPLY_PROP_HEALTH,
+ POWER_SUPPLY_PROP_PRESENT,
+ POWER_SUPPLY_PROP_TECHNOLOGY,
+ POWER_SUPPLY_PROP_CYCLE_COUNT,
+ POWER_SUPPLY_PROP_VOLTAGE_NOW,
+ POWER_SUPPLY_PROP_CURRENT_NOW,
+ POWER_SUPPLY_PROP_CAPACITY,
+ POWER_SUPPLY_PROP_TEMP,
+ POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
+ POWER_SUPPLY_PROP_TIME_TO_FULL_AVG,
+ POWER_SUPPLY_PROP_SERIAL_NUMBER,
+};
+
+static int bq20z75_get_property(struct power_supply *psy,
+ enum power_supply_property psp, union power_supply_propval *val);
+
+static struct power_supply bq20z75_supply = {
+ .name = "battery",
+ .type = POWER_SUPPLY_TYPE_BATTERY,
+ .properties = bq20z75_properties,
+ .num_properties = ARRAY_SIZE(bq20z75_properties),
+ .get_property = bq20z75_get_property,
+};
+
+struct bq20z75_device_info {
+ struct i2c_client *client;
+} *bq20z75_device;
+
+static int bq20z75_get_battery_presence_and_health(
+ enum power_supply_property psp, union power_supply_propval *val)
+{
+ s32 ret;
+
+ /* Write to ManufacturerAccess with
+ * ManufacturerAccess command and then
+ * read the status */
+ ret = i2c_smbus_write_word_data(bq20z75_device->client,
+ bq20z75_data[REG_MANUFACTURER_DATA].addr,
+ MANUFACTURER_ACCESS_STATUS);
+ if (ret < 0) {
+ dev_err(&bq20z75_device->client->dev,
+ "%s: i2c write for battery presence failed\n",
+ __func__);
+ return -EINVAL;
+ }
+
+ ret = i2c_smbus_read_word_data(bq20z75_device->client,
+ bq20z75_data[REG_MANUFACTURER_DATA].addr);
+ if (ret < 0) {
+ dev_err(&bq20z75_device->client->dev,
+ "%s: i2c read for battery presence failed\n",
+ __func__);
+ return -EINVAL;
+ }
+
+ if (ret < bq20z75_data[REG_MANUFACTURER_DATA].min_value ||
+ ret > bq20z75_data[REG_MANUFACTURER_DATA].max_value) {
+ val->intval = 0;
+ return 0;
+ }
+
+ /* Mask the upper nibble of 2nd byte and
+ * lower byte of response then
+ * shift the result by 8 to get status*/
+ ret &= 0x0F00;
+ ret >>= 8;
+ if (psp == POWER_SUPPLY_PROP_PRESENT) {
+ if (ret == 0x0F)
+ /* battery removed */
+ val->intval = 0;
+ else
+ val->intval = 1;
+ } else if (psp == POWER_SUPPLY_PROP_HEALTH) {
+ if (ret == 0x09)
+ val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
+ else if (ret == 0x0B)
+ val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
+ else if (ret == 0x0C)
+ val->intval = POWER_SUPPLY_HEALTH_DEAD;
+ else
+ val->intval = POWER_SUPPLY_HEALTH_GOOD;
+ }
+
+ return 0;
+}
+
+static int bq20z75_get_battery_property(int reg_offset,
+ enum power_supply_property psp,
+ union power_supply_propval *val)
+{
+ s32 ret;
+
+ ret = i2c_smbus_read_word_data(bq20z75_device->client,
+ bq20z75_data[reg_offset].addr);
+ if (ret < 0) {
+ dev_err(&bq20z75_device->client->dev,
+ "%s: i2c read for %d failed\n", __func__, reg_offset);
+ return -EINVAL;
+ }
+
+ if (ret >= bq20z75_data[reg_offset].min_value &&
+ ret <= bq20z75_data[reg_offset].max_value) {
+ val->intval = ret;
+ if (psp == POWER_SUPPLY_PROP_STATUS) {
+ /* mask the upper byte and then find the
+ * actual status */
+ ret &= 0x00FF;
+ if (ret & BATTERY_CHARGING)
+ val->intval = POWER_SUPPLY_STATUS_CHARGING;
+ else if (ret & BATTERY_FULL_CHARGED)
+ val->intval = POWER_SUPPLY_STATUS_FULL;
+ else if (ret & BATTERY_FULL_DISCHARGED)
+ val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+ else
+ val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+ }
+ /* bq20z75 provides battery tempreture in 0.1°K
+ * so convert it to °C */
+ else if (psp == POWER_SUPPLY_PROP_TEMP)
+ val->intval = ret - 2731;
+ } else {
+ val->intval = 0;
+ if (psp == POWER_SUPPLY_PROP_STATUS)
+ val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
+ }
+
+ return 0;
+}
+
+static int bq20z75_get_battery_capacity(union power_supply_propval *val)
+{
+ s32 ret;
+
+ ret = i2c_smbus_read_byte_data(bq20z75_device->client,
+ bq20z75_data[REG_CAPACITY].addr);
+ if (ret < 0) {
+ dev_err(&bq20z75_device->client->dev,
+ "%s: i2c read for %d failed\n", __func__, REG_CAPACITY);
+ return -EINVAL;
+ }
+
+ /* bq20z75 spec says that this can be >100 %
+ * even if max value is 100 % */
+ val->intval = ((ret >= 100) ? 100 : ret);
+
+ return 0;
+}
+
+static int bq20z75_get_property(struct power_supply *psy,
+ enum power_supply_property psp,
+ union power_supply_propval *val)
+{
+ u8 count;
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_PRESENT:
+ case POWER_SUPPLY_PROP_HEALTH:
+ if (bq20z75_get_battery_presence_and_health(psp, val))
+ return -EINVAL;
+ break;
+
+ case POWER_SUPPLY_PROP_TECHNOLOGY:
+ val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
+ break;
+
+ case POWER_SUPPLY_PROP_CAPACITY:
+ if (bq20z75_get_battery_capacity(val))
+ return -EINVAL;
+ break;
+
+ case POWER_SUPPLY_PROP_STATUS:
+ case POWER_SUPPLY_PROP_CYCLE_COUNT:
+ case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+ case POWER_SUPPLY_PROP_CURRENT_NOW:
+ case POWER_SUPPLY_PROP_TEMP:
+ case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
+ case POWER_SUPPLY_PROP_TIME_TO_FULL_AVG:
+ case POWER_SUPPLY_PROP_SERIAL_NUMBER:
+ for (count = 0; count < REG_MAX; count++) {
+ if (psp == bq20z75_data[count].psp)
+ break;
+ }
+
+ if (bq20z75_get_battery_property(count, psp, val))
+ return -EINVAL;
+ break;
+
+ default:
+ dev_err(&bq20z75_device->client->dev,
+ "%s: INVALID property\n", __func__);
+ return -EINVAL;
+ }
+
+ printk(KERN_INFO "%s: property = %d, value = %d\n", __func__,
+ psp, val->intval);
+
+ return 0;
+}
+
+static int bq20z75_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int rc;
+
+ bq20z75_device = kzalloc(sizeof(*bq20z75_device), GFP_KERNEL);
+ if (!bq20z75_device)
+ return -ENOMEM;
+
+memset(bq20z75_device, 0, sizeof(*bq20z75_device));
+
+ bq20z75_device->client = client;
+ i2c_set_clientdata(client, bq20z75_device);
+
+ rc = power_supply_register(&client->dev, &bq20z75_supply);
+ if (rc) {
+ dev_err(&bq20z75_device->client->dev,
+ "%s: Failed to register power supply\n", __func__);
+ kfree(bq20z75_device);
+ return rc;
+ }
+
+ dev_info(&bq20z75_device->client->dev,
+ "%s: battery driver registered\n", client->name);
+
+ return 0;
+}
+
+static int bq20z75_remove(struct i2c_client *client)
+{
+ struct bq20z75_device_info *bq20z75_device = i2c_get_clientdata(client);
+
+ power_supply_unregister(&bq20z75_supply);
+ kfree(bq20z75_device);
+ bq20z75_device = NULL;
+
+ return 0;
+}
+
+#if defined CONFIG_PM
+static int bq20z75_suspend(struct i2c_client *client,
+ pm_message_t state)
+{
+ s32 ret;
+ struct bq20z75_device_info *bq20z75_device = i2c_get_clientdata(client);
+
+ /* write to manufacture access with sleep command */
+ ret = i2c_smbus_write_word_data(bq20z75_device->client,
+ bq20z75_data[REG_MANUFACTURER_DATA].addr,
+ MANUFACTURER_ACCESS_SLEEP);
+ if (ret < 0) {
+ dev_err(&bq20z75_device->client->dev,
+ "%s: i2c write for %d failed\n",
+ __func__, MANUFACTURER_ACCESS_SLEEP);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/* any smbus transaction will wake up bq20z75 */
+static int bq20z75_resume(struct i2c_client *client)
+{
+ return 0;
+}
+#endif
+
+static const struct i2c_device_id bq20z75_id[] = {
+ { "bq20z75-battery", 0 },
+ {},
+};
+
+static struct i2c_driver bq20z75_battery_driver = {
+ .probe = bq20z75_probe,
+ .remove = bq20z75_remove,
+#if defined CONFIG_PM
+ .suspend = bq20z75_suspend,
+ .resume = bq20z75_resume,
+#endif
+ .id_table = bq20z75_id,
+ .driver = {
+ .name = "bq20z75-battery",
+ },
+};
+
+static int __init bq20z75_battery_init(void)
+{
+ int ret;
+
+ ret = i2c_add_driver(&bq20z75_battery_driver);
+ if (ret)
+ dev_err(&bq20z75_device->client->dev,
+ "%s: i2c_add_driver failed\n", __func__);
+
+ return ret;
+}
+module_init(bq20z75_battery_init);
+
+static void __exit bq20z75_battery_exit(void)
+{
+ i2c_del_driver(&bq20z75_battery_driver);
+}
+module_exit(bq20z75_battery_exit);
+
+MODULE_AUTHOR("NVIDIA Graphics Pvt Ltd");
+MODULE_DESCRIPTION("BQ20z75 battery monitor driver");
+MODULE_LICENSE("GPL");
--
1.7.0.4
--
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