power_supply: Add gpio charger driver

This patch adds a simple driver for chargers indicating their online
status through a GPIO pin.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>

4 files changed, 237 insertions, 0 deletions

diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index 60d83d983a36..32165295cb1b 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -185,4 +185,14 @@ config CHARGER_TWL4030
         help
           Say Y here to enable support for TWL4030 Battery Charge Interface.
 
+config CHARGER_GPIO
+        tristate "GPIO charger"
+        depends on GPIOLIB
+        help
+          Say Y to include support for chargers which report their online status
+          through a GPIO pin.
+
+          This driver can be build as a module. If so, the module will be
+          called gpio-charger.
+
 endif # POWER_SUPPLY
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index c75772eb157c..545459f9f356 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -32,3 +32,4 @@ obj-$(CONFIG_BATTERY_JZ4740)	+= jz4740-battery.o
 obj-$(CONFIG_BATTERY_INTEL_MID) += intel_mid_battery.o
 obj-$(CONFIG_CHARGER_ISP1704)   += isp1704_charger.o
 obj-$(CONFIG_CHARGER_TWL4030)   += twl4030_charger.o
+obj-$(CONFIG_CHARGER_GPIO)      += gpio-charger.o
diff --git a/drivers/power/gpio-charger.c b/drivers/power/gpio-charger.c
new file mode 100644
index 000000000000..fccbe99b619c
--- /dev/null
+++ b/drivers/power/gpio-charger.c
@@ -0,0 +1,185 @@
+/*
+ *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
+ *  Driver for chargers which report their online status through a GPIO pin
+ *
+ *  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.
+ *
+ *  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.,
+ *  675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <linux/device.h>
+#include <linux/gpio.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/slab.h>
+
+#include <linux/power/gpio-charger.h>
+
+struct gpio_charger {
+        const struct gpio_charger_platform_data *pdata;
+        unsigned int irq;
+
+        struct power_supply charger;
+};
+
+static irqreturn_t gpio_charger_irq(int irq, void *devid)
+{
+        struct power_supply *charger = devid;
+
+        power_supply_changed(charger);
+
+        return IRQ_HANDLED;
+}
+
+static inline struct gpio_charger *psy_to_gpio_charger(struct power_supply *psy)
+{
+        return container_of(psy, struct gpio_charger, charger);
+}
+
+static int gpio_charger_get_property(struct power_supply *psy,
+                enum power_supply_property psp, union power_supply_propval *val)
+{
+        struct gpio_charger *gpio_charger = psy_to_gpio_charger(psy);
+        const struct gpio_charger_platform_data *pdata = gpio_charger->pdata;
+
+        switch (psp) {
+        case POWER_SUPPLY_PROP_ONLINE:
+                val->intval = gpio_get_value(pdata->gpio);
+                val->intval ^= pdata->gpio_active_low;
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        return 0;
+}
+
+static enum power_supply_property gpio_charger_properties[] = {
+        POWER_SUPPLY_PROP_ONLINE,
+};
+
+static int __devinit gpio_charger_probe(struct platform_device *pdev)
+{
+        const struct gpio_charger_platform_data *pdata = pdev->dev.platform_data;
+        struct gpio_charger *gpio_charger;
+        struct power_supply *charger;
+        int ret;
+        int irq;
+
+        if (!pdata) {
+                dev_err(&pdev->dev, "No platform data\n");
+                return -EINVAL;
+        }
+
+        if (!gpio_is_valid(pdata->gpio)) {
+                dev_err(&pdev->dev, "Invalid gpio pin\n");
+                return -EINVAL;
+        }
+
+        gpio_charger = kzalloc(sizeof(*gpio_charger), GFP_KERNEL);
+
+        charger = &gpio_charger->charger;
+
+        charger->name = pdata->name;
+        charger->type = pdata->type;
+        charger->properties = gpio_charger_properties;
+        charger->num_properties = ARRAY_SIZE(gpio_charger_properties);
+        charger->get_property  = gpio_charger_get_property;
+        charger->supplied_to = pdata->supplied_to;
+        charger->num_supplicants = pdata->num_supplicants;
+
+        ret = gpio_request(pdata->gpio, dev_name(&pdev->dev));
+        if (ret) {
+                dev_err(&pdev->dev, "Failed to request gpio pin: %d\n", ret);
+                goto err_free;
+        }
+        ret = gpio_direction_input(pdata->gpio);
+        if (ret) {
+                dev_err(&pdev->dev, "Failed to set gpio to input: %d\n", ret);
+                goto err_gpio_free;
+        }
+
+        irq = gpio_to_irq(pdata->gpio);
+        if (irq > 0) {
+                ret = request_irq(irq, gpio_charger_irq,
+                                IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
+                                dev_name(&pdev->dev), charger);
+                if (ret)
+                        dev_warn(&pdev->dev, "Failed to request irq: %d\n", ret);
+                else
+                        gpio_charger->irq = irq;
+        }
+
+        gpio_charger->pdata = pdata;
+
+        ret = power_supply_register(&pdev->dev, charger);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "Failed to register power supply: %d\n", ret);
+                goto err_irq_free;
+        }
+
+        platform_set_drvdata(pdev, gpio_charger);
+
+        return 0;
+
+err_irq_free:
+        if (gpio_charger->irq)
+                free_irq(gpio_charger->irq, charger);
+err_gpio_free:
+        gpio_free(pdata->gpio);
+err_free:
+        kfree(gpio_charger);
+        return ret;
+}
+
+static int __devexit gpio_charger_remove(struct platform_device *pdev)
+{
+        struct gpio_charger *gpio_charger = platform_get_drvdata(pdev);
+
+        power_supply_unregister(&gpio_charger->charger);
+
+        if (gpio_charger->irq)
+                free_irq(gpio_charger->irq, &gpio_charger->charger);
+        gpio_free(gpio_charger->pdata->gpio);
+
+        platform_set_drvdata(pdev, NULL);
+        kfree(gpio_charger);
+
+        return 0;
+}
+
+static struct platform_driver gpio_charger_driver = {
+        .probe = gpio_charger_probe,
+        .remove = __devexit_p(gpio_charger_remove),
+        .driver = {
+                .name = "gpio-charger",
+                .owner = THIS_MODULE,
+        },
+};
+
+static int __init gpio_charger_init(void)
+{
+        return platform_driver_register(&gpio_charger_driver);
+}
+module_init(gpio_charger_init);
+
+static void __exit gpio_charger_exit(void)
+{
+        platform_driver_unregister(&gpio_charger_driver);
+}
+module_exit(gpio_charger_exit);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("Driver for chargers which report their online status through a GPIO");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:gpio-charger");
diff --git a/include/linux/power/gpio-charger.h b/include/linux/power/gpio-charger.h
new file mode 100644
index 000000000000..de1dfe09a03d
--- /dev/null
+++ b/include/linux/power/gpio-charger.h
@@ -0,0 +1,41 @@
+/*
+ *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
+ *
+ *  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.
+ *
+ *  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.,
+ *  675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#ifndef __LINUX_POWER_GPIO_CHARGER_H__
+#define __LINUX_POWER_GPIO_CHARGER_H__
+
+#include <linux/power_supply.h>
+#include <linux/types.h>
+
+/**
+ * struct gpio_charger_platform_data - platform_data for gpio_charger devices
+ * @name:               Name for the chargers power_supply device
+ * @type:               Type of the charger
+ * @gpio:               GPIO which is used to indicate the chargers status
+ * @gpio_active_low:    Should be set to 1 if the GPIO is active low otherwise 0
+ * @supplied_to:        Array of battery names to which this chargers supplies power
+ * @num_supplicants:    Number of entries in the supplied_to array
+ */
+struct gpio_charger_platform_data {
+        const char *name;
+        enum power_supply_type type;
+
+        int gpio;
+        int gpio_active_low;
+
+        char **supplied_to;
+        size_t num_supplicants;
+};
+
+#endif