bq20z75: Add optional battery detect gpio

Adding support for an optional gpio for battery detection. This is
passed in through the i2c platform data. It also accepts another
field, battery_detect_present to signify the gpio state which means
the battery is present, either 0 (low) or 1 (high).

Signed-off-by: Rhyland Klein <rklein@nvidia.com>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>

2 files changed, 166 insertions, 31 deletions

diff --git a/drivers/power/bq20z75.c b/drivers/power/bq20z75.c
index 4141775e5ff..a51e98d74d3 100644
--- a/drivers/power/bq20z75.c
+++ b/drivers/power/bq20z75.c
@@ -25,6 +25,10 @@
 #include <linux/power_supply.h>
 #include <linux/i2c.h>
 #include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/gpio.h>
+
+#include <linux/power/bq20z75.h>
 
 enum {
         REG_MANUFACTURER_DATA,
@@ -141,8 +145,13 @@ static enum power_supply_property bq20z75_properties[] = {
 };
 
 struct bq20z75_info {
-        struct i2c_client       *client;
-        struct power_supply     power_supply;
+        struct i2c_client               *client;
+        struct power_supply             power_supply;
+        struct bq20z75_platform_data    *pdata;
+        bool                            is_present;
+        bool                            gpio_detect;
+        bool                            enable_detection;
+        int                             irq;
 };
 
 static int bq20z75_read_word_data(struct i2c_client *client, u8 address)
@@ -179,6 +188,18 @@ static int bq20z75_get_battery_presence_and_health(
         union power_supply_propval *val)
 {
         s32 ret;
+        struct bq20z75_info *bq20z75_device = i2c_get_clientdata(client);
+
+        if (psp == POWER_SUPPLY_PROP_PRESENT &&
+                bq20z75_device->gpio_detect) {
+                ret = gpio_get_value(
+                        bq20z75_device->pdata->battery_detect);
+                if (ret == bq20z75_device->pdata->battery_detect_present)
+                        val->intval = 1;
+                else
+                        val->intval = 0;
+                return ret;
+        }
 
         /* Write to ManufacturerAccess with
          * ManufacturerAccess command and then
@@ -192,8 +213,11 @@ static int bq20z75_get_battery_presence_and_health(
 
         ret = bq20z75_read_word_data(client,
                 bq20z75_data[REG_MANUFACTURER_DATA].addr);
-        if (ret < 0)
+        if (ret < 0) {
+                if (psp == POWER_SUPPLY_PROP_PRESENT)
+                        val->intval = 0; /* battery removed */
                 return ret;
+        }
 
         if (ret < bq20z75_data[REG_MANUFACTURER_DATA].min_value ||
             ret > bq20z75_data[REG_MANUFACTURER_DATA].max_value) {
@@ -397,8 +421,7 @@ static int bq20z75_get_property(struct power_supply *psy,
         enum power_supply_property psp,
         union power_supply_propval *val)
 {
-        int ps_index;
-        int ret;
+        int ret = 0;
         struct bq20z75_info *bq20z75_device = container_of(psy,
                                 struct bq20z75_info, power_supply);
         struct i2c_client *client = bq20z75_device->client;
@@ -407,8 +430,6 @@ static int bq20z75_get_property(struct power_supply *psy,
         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:
@@ -422,20 +443,15 @@ static int bq20z75_get_property(struct power_supply *psy,
         case POWER_SUPPLY_PROP_CHARGE_FULL:
         case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
         case POWER_SUPPLY_PROP_CAPACITY:
-                ps_index = bq20z75_get_property_index(client, psp);
-                if (ps_index < 0)
-                        return ps_index;
-
-                ret = bq20z75_get_battery_capacity(client, ps_index, psp, val);
-                if (ret)
-                        return ret;
+                ret = bq20z75_get_property_index(client, psp);
+                if (ret < 0)
+                        break;
 
+                ret = bq20z75_get_battery_capacity(client, ret, psp, val);
                 break;
 
         case POWER_SUPPLY_PROP_SERIAL_NUMBER:
                 ret = bq20z75_get_battery_serial_number(client, val);
-                if (ret)
-                        return ret;
                 break;
 
         case POWER_SUPPLY_PROP_STATUS:
@@ -446,14 +462,11 @@ static int bq20z75_get_property(struct power_supply *psy,
         case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
         case POWER_SUPPLY_PROP_TIME_TO_FULL_AVG:
         case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
-                ps_index = bq20z75_get_property_index(client, psp);
-                if (ps_index < 0)
-                        return ps_index;
-
-                ret = bq20z75_get_battery_property(client, ps_index, psp, val);
-                if (ret)
-                        return ret;
+                ret = bq20z75_get_property_index(client, psp);
+                if (ret < 0)
+                        break;
 
+                ret = bq20z75_get_battery_property(client, ret, psp, val);
                 break;
 
         default:
@@ -462,26 +475,51 @@ static int bq20z75_get_property(struct power_supply *psy,
                 return -EINVAL;
         }
 
-        /* Convert units to match requirements for power supply class */
-        bq20z75_unit_adjustment(client, psp, val);
+        if (!bq20z75_device->enable_detection)
+                goto done;
+
+        if (!bq20z75_device->gpio_detect &&
+                bq20z75_device->is_present != (ret >= 0)) {
+                bq20z75_device->is_present = (ret >= 0);
+                power_supply_changed(&bq20z75_device->power_supply);
+        }
+
+done:
+        if (!ret) {
+                /* Convert units to match requirements for power supply class */
+                bq20z75_unit_adjustment(client, psp, val);
+        }
 
         dev_dbg(&client->dev,
                 "%s: property = %d, value = %d\n", __func__, psp, val->intval);
 
-        return 0;
+        return ret;
 }
 
-static int bq20z75_probe(struct i2c_client *client,
+static irqreturn_t bq20z75_irq(int irq, void *devid)
+{
+        struct power_supply *battery = devid;
+
+        power_supply_changed(battery);
+
+        return IRQ_HANDLED;
+}
+
+static int __devinit bq20z75_probe(struct i2c_client *client,
         const struct i2c_device_id *id)
 {
         struct bq20z75_info *bq20z75_device;
+        struct bq20z75_platform_data *pdata = client->dev.platform_data;
         int rc;
+        int irq;
 
         bq20z75_device = kzalloc(sizeof(struct bq20z75_info), GFP_KERNEL);
         if (!bq20z75_device)
                 return -ENOMEM;
 
         bq20z75_device->client = client;
+        bq20z75_device->enable_detection = false;
+        bq20z75_device->gpio_detect = false;
         bq20z75_device->power_supply.name = "battery";
         bq20z75_device->power_supply.type = POWER_SUPPLY_TYPE_BATTERY;
         bq20z75_device->power_supply.properties = bq20z75_properties;
@@ -489,26 +527,86 @@ static int bq20z75_probe(struct i2c_client *client,
                 ARRAY_SIZE(bq20z75_properties);
         bq20z75_device->power_supply.get_property = bq20z75_get_property;
 
+        if (pdata) {
+                bq20z75_device->gpio_detect =
+                        gpio_is_valid(pdata->battery_detect);
+                bq20z75_device->pdata = pdata;
+        }
+
         i2c_set_clientdata(client, bq20z75_device);
 
+        if (!bq20z75_device->gpio_detect)
+                goto skip_gpio;
+
+        rc = gpio_request(pdata->battery_detect, dev_name(&client->dev));
+        if (rc) {
+                dev_warn(&client->dev, "Failed to request gpio: %d\n", rc);
+                bq20z75_device->gpio_detect = false;
+                goto skip_gpio;
+        }
+
+        rc = gpio_direction_input(pdata->battery_detect);
+        if (rc) {
+                dev_warn(&client->dev, "Failed to get gpio as input: %d\n", rc);
+                gpio_free(pdata->battery_detect);
+                bq20z75_device->gpio_detect = false;
+                goto skip_gpio;
+        }
+
+        irq = gpio_to_irq(pdata->battery_detect);
+        if (irq <= 0) {
+                dev_warn(&client->dev, "Failed to get gpio as irq: %d\n", irq);
+                gpio_free(pdata->battery_detect);
+                bq20z75_device->gpio_detect = false;
+                goto skip_gpio;
+        }
+
+        rc = request_irq(irq, bq20z75_irq,
+                IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
+                dev_name(&client->dev), &bq20z75_device->power_supply);
+        if (rc) {
+                dev_warn(&client->dev, "Failed to request irq: %d\n", rc);
+                gpio_free(pdata->battery_detect);
+                bq20z75_device->gpio_detect = false;
+                goto skip_gpio;
+        }
+
+        bq20z75_device->irq = irq;
+
+skip_gpio:
+
         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;
+                goto exit_psupply;
         }
 
         dev_info(&client->dev,
                 "%s: battery gas gauge device registered\n", client->name);
 
         return 0;
+
+exit_psupply:
+        if (bq20z75_device->irq)
+                free_irq(bq20z75_device->irq, &bq20z75_device->power_supply);
+        if (bq20z75_device->gpio_detect)
+                gpio_free(pdata->battery_detect);
+
+        kfree(bq20z75_device);
+
+        return rc;
 }
 
-static int bq20z75_remove(struct i2c_client *client)
+static int __devexit bq20z75_remove(struct i2c_client *client)
 {
         struct bq20z75_info *bq20z75_device = i2c_get_clientdata(client);
 
+        if (bq20z75_device->irq)
+                free_irq(bq20z75_device->irq, &bq20z75_device->power_supply);
+        if (bq20z75_device->gpio_detect)
+                gpio_free(bq20z75_device->pdata->battery_detect);
+
         power_supply_unregister(&bq20z75_device->power_supply);
         kfree(bq20z75_device);
         bq20z75_device = NULL;
@@ -544,7 +642,7 @@ static const struct i2c_device_id bq20z75_id[] = {
 
 static struct i2c_driver bq20z75_battery_driver = {
         .probe          = bq20z75_probe,
-        .remove         = bq20z75_remove,
+        .remove         = __devexit_p(bq20z75_remove),
         .suspend        = bq20z75_suspend,
         .resume         = bq20z75_resume,
         .id_table       = bq20z75_id,
diff --git a/include/linux/power/bq20z75.h b/include/linux/power/bq20z75.h
new file mode 100644
index 00000000000..0e1b8a26a9b
--- /dev/null
+++ b/include/linux/power/bq20z75.h
@@ -0,0 +1,37 @@
+/*
+ * 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.
+ */
+
+#ifndef __LINUX_POWER_BQ20Z75_H_
+#define __LINUX_POWER_BQ20Z75_H_
+
+#include <linux/power_supply.h>
+#include <linux/types.h>
+
+/**
+ * struct bq20z75_platform_data - platform data for bq20z75 devices
+ * @battery_detect:             GPIO which is used to detect battery presence
+ * @battery_detect_present:     gpio state when battery is present (0 / 1)
+ */
+struct bq20z75_platform_data {
+        int battery_detect;
+        int battery_detect_present;
+};
+
+#endif