power_supply: Add driver for TI BQ20Z75 gas gauge IC

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

Signed-off-by: Rhyland Klein <rklein@nvidia.com>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>

3 files changed, 393 insertions, 0 deletions

diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index c2a1b8b713f6..4d9a637539b6 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -109,6 +109,13 @@ config BATTERY_WM97XX
         help
           Say Y to enable support for battery measured by WM97xx aux port.
 
+config BATTERY_BQ20Z75
+        tristate "TI BQ20z75 gas gauge"
+        depends on I2C
+        help
+         Say Y to include support for TI BQ20z75 SBS-compliant
+         gas gauge and protection IC.
+
 config BATTERY_BQ27x00
         tristate "BQ27x00 battery driver"
         depends on I2C
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index c73d381037a0..2799a8418186 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_BATTERY_OLPC)	+= olpc_battery.o
 obj-$(CONFIG_BATTERY_TOSA)      += tosa_battery.o
 obj-$(CONFIG_BATTERY_COLLIE)    += collie_battery.o
 obj-$(CONFIG_BATTERY_WM97XX)    += wm97xx_battery.o
+obj-$(CONFIG_BATTERY_BQ20Z75)   += bq20z75.o
 obj-$(CONFIG_BATTERY_BQ27x00)   += bq27x00_battery.o
 obj-$(CONFIG_BATTERY_DA9030)    += da9030_battery.o
 obj-$(CONFIG_BATTERY_MAX17040)  += max17040_battery.o
diff --git a/drivers/power/bq20z75.c b/drivers/power/bq20z75.c
new file mode 100644
index 000000000000..a1c7ae2ec9f8
--- /dev/null
+++ b/drivers/power/bq20z75.c
@@ -0,0 +1,385 @@
+/*
+ * 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/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
+};
+
+/* 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 const 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,
+};
+
+struct bq20z75_info {
+        struct i2c_client       *client;
+        struct power_supply     power_supply;
+};
+
+static int bq20z75_get_battery_presence_and_health(
+        struct i2c_client *client, 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(client,
+                bq20z75_data[REG_MANUFACTURER_DATA].addr,
+                MANUFACTURER_ACCESS_STATUS);
+        if (ret < 0) {
+                dev_err(&client->dev,
+                        "%s: i2c write for battery presence failed\n",
+                        __func__);
+                return -ENODEV;
+        }
+
+        ret = i2c_smbus_read_word_data(client,
+                bq20z75_data[REG_MANUFACTURER_DATA].addr);
+        if (ret < 0) {
+                dev_err(&client->dev,
+                        "%s: i2c read for battery presence failed\n",
+                        __func__);
+                return -EIO;
+        }
+
+        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(struct i2c_client *client,
+        int reg_offset, enum power_supply_property psp,
+        union power_supply_propval *val)
+{
+        s32 ret;
+
+        ret = i2c_smbus_read_word_data(client,
+                bq20z75_data[reg_offset].addr);
+        if (ret < 0) {
+                dev_err(&client->dev,
+                        "%s: i2c read for %d failed\n", __func__, reg_offset);
+                return -EIO;
+        }
+
+        if (ret >= bq20z75_data[reg_offset].min_value &&
+            ret <= bq20z75_data[reg_offset].max_value) {
+                val->intval = ret;
+                if (psp == POWER_SUPPLY_PROP_STATUS) {
+                        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 {
+                if (psp == POWER_SUPPLY_PROP_STATUS)
+                        val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
+                else
+                        val->intval = 0;
+        }
+
+        return 0;
+}
+
+static int bq20z75_get_battery_capacity(struct i2c_client *client,
+        union power_supply_propval *val)
+{
+        s32 ret;
+
+        ret = i2c_smbus_read_byte_data(client, bq20z75_data[REG_CAPACITY].addr);
+        if (ret < 0) {
+                dev_err(&client->dev,
+                        "%s: i2c read for %d failed\n", __func__, REG_CAPACITY);
+                return -EIO;
+        }
+
+        /* bq20z75 spec says that this can be >100 %
+         * even if max value is 100 % */
+        val->intval = min(ret, 100);
+
+        return 0;
+}
+
+static int bq20z75_get_property(struct power_supply *psy,
+        enum power_supply_property psp,
+        union power_supply_propval *val)
+{
+        int count;
+        int ret;
+        struct bq20z75_info *bq20z75_device = container_of(psy,
+                                struct bq20z75_info, power_supply);
+        struct i2c_client *client = bq20z75_device->client;
+
+        switch (psp) {
+        case POWER_SUPPLY_PROP_PRESENT:
+        case POWER_SUPPLY_PROP_HEALTH:
+                ret = bq20z75_get_battery_presence_and_health(client, psp, val);
+                if (ret)
+                        return ret;
+                break;
+
+        case POWER_SUPPLY_PROP_TECHNOLOGY:
+                val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
+                break;
+
+        case POWER_SUPPLY_PROP_CAPACITY:
+                ret = bq20z75_get_battery_capacity(client, val);
+                if (ret)
+                        return ret;
+                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 < ARRAY_SIZE(bq20z75_data); count++) {
+                        if (psp == bq20z75_data[count].psp)
+                                break;
+                }
+
+                ret = bq20z75_get_battery_property(client, count, psp, val);
+                if (ret)
+                        return ret;
+                break;
+
+        default:
+                dev_err(&client->dev,
+                        "%s: INVALID property\n", __func__);
+                return -EINVAL;
+        }
+
+        dev_dbg(&client->dev,
+                "%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)
+{
+        struct bq20z75_info *bq20z75_device;
+        int rc;
+
+        bq20z75_device = kzalloc(sizeof(struct bq20z75_info), GFP_KERNEL);
+        if (!bq20z75_device)
+                return -ENOMEM;
+
+        bq20z75_device->client = client;
+        bq20z75_device->power_supply.name = "battery";
+        bq20z75_device->power_supply.type = POWER_SUPPLY_TYPE_BATTERY;
+        bq20z75_device->power_supply.properties = bq20z75_properties;
+        bq20z75_device->power_supply.num_properties =
+                ARRAY_SIZE(bq20z75_properties);
+        bq20z75_device->power_supply.get_property = bq20z75_get_property;
+
+        i2c_set_clientdata(client, bq20z75_device);
+
+        rc = power_supply_register(&client->dev, &bq20z75_device->power_supply);
+        if (rc) {
+                dev_err(&client->dev,
+                        "%s: Failed to register power supply\n", __func__);
+                kfree(bq20z75_device);
+                return rc;
+        }
+
+        dev_info(&client->dev,
+                "%s: battery gas gauge device registered\n", client->name);
+
+        return 0;
+}
+
+static int bq20z75_remove(struct i2c_client *client)
+{
+        struct bq20z75_info *bq20z75_device = i2c_get_clientdata(client);
+
+        power_supply_unregister(&bq20z75_device->power_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;
+
+        /* write to manufacturer access with sleep command */
+        ret = i2c_smbus_write_word_data(client,
+                bq20z75_data[REG_MANUFACTURER_DATA].addr,
+                MANUFACTURER_ACCESS_SLEEP);
+        if (ret < 0) {
+                dev_err(&client->dev,
+                        "%s: i2c write for %d failed\n",
+                        __func__, MANUFACTURER_ACCESS_SLEEP);
+                return -EIO;
+        }
+
+        return 0;
+}
+#else
+#define bq20z75_suspend         NULL
+#endif
+/* any smbus transaction will wake up bq20z75 */
+#define bq20z75_resume          NULL
+
+static const struct i2c_device_id bq20z75_id[] = {
+        { "bq20z75", 0 },
+        {}
+};
+
+static struct i2c_driver bq20z75_battery_driver = {
+        .probe          = bq20z75_probe,
+        .remove         = bq20z75_remove,
+        .suspend        = bq20z75_suspend,
+        .resume         = bq20z75_resume,
+        .id_table       = bq20z75_id,
+        .driver = {
+                .name   = "bq20z75-battery",
+        },
+};
+
+static int __init bq20z75_battery_init(void)
+{
+        return i2c_add_driver(&bq20z75_battery_driver);
+}
+module_init(bq20z75_battery_init);
+
+static void __exit bq20z75_battery_exit(void)
+{
+        i2c_del_driver(&bq20z75_battery_driver);
+}
+module_exit(bq20z75_battery_exit);
+
+MODULE_DESCRIPTION("BQ20z75 battery monitor driver");
+MODULE_LICENSE("GPL");