drivers/power/gpio-charger.c

   1 /*
   2  *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
   3  *  Driver for chargers which report their online status through a GPIO pin
   4  *
   5  *  This program is free software; you can redistribute it and/or modify it
   6  *  under  the terms of the GNU General  Public License as published by the
   7  *  Free Software Foundation;  either version 2 of the License, or (at your
   8  *  option) any later version.
   9  *
  10  *  You should have received a copy of the GNU General Public License along
  11  *  with this program; if not, write to the Free Software Foundation, Inc.,
  12  *  675 Mass Ave, Cambridge, MA 02139, USA.
  13  *
  14  */
  15
  16 #include <linux/device.h>
  17 #include <linux/gpio.h>
  18 #include <linux/init.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/power_supply.h>
  24 #include <linux/slab.h>
  25
  26 #include <linux/power/gpio-charger.h>
  27
  28 struct gpio_charger {
  29         const struct gpio_charger_platform_data *pdata;
  30         unsigned int irq;
  31
  32         struct power_supply charger;
  33 };
  34
  35 static irqreturn_t gpio_charger_irq(int irq, void *devid)
  36 {
  37         struct power_supply *charger = devid;
  38
  39         power_supply_changed(charger);
  40
  41         return IRQ_HANDLED;
  42 }
  43
  44 static inline struct gpio_charger *psy_to_gpio_charger(struct power_supply *psy)
  45 {
  46         return container_of(psy, struct gpio_charger, charger);
  47 }
  48
  49 static int gpio_charger_get_property(struct power_supply *psy,
  50                 enum power_supply_property psp, union power_supply_propval *val)
  51 {
  52         struct gpio_charger *gpio_charger = psy_to_gpio_charger(psy);
  53         const struct gpio_charger_platform_data *pdata = gpio_charger->pdata;
  54
  55         switch (psp) {
  56         case POWER_SUPPLY_PROP_ONLINE:
  57                 val->intval = gpio_get_value(pdata->gpio);
  58                 val->intval ^= pdata->gpio_active_low;
  59                 break;
  60         default:
  61                 return -EINVAL;
  62         }
  63
  64         return 0;
  65 }
  66
  67 static enum power_supply_property gpio_charger_properties[] = {
  68         POWER_SUPPLY_PROP_ONLINE,
  69 };
  70
  71 static int __devinit gpio_charger_probe(struct platform_device *pdev)
  72 {
  73         const struct gpio_charger_platform_data *pdata = pdev->dev.platform_data;
  74         struct gpio_charger *gpio_charger;
  75         struct power_supply *charger;
  76         int ret;
  77         int irq;
  78
  79         if (!pdata) {
  80                 dev_err(&pdev->dev, "No platform data\n");
  81                 return -EINVAL;
  82         }
  83
  84         if (!gpio_is_valid(pdata->gpio)) {
  85                 dev_err(&pdev->dev, "Invalid gpio pin\n");
  86                 return -EINVAL;
  87         }
  88
  89         gpio_charger = kzalloc(sizeof(*gpio_charger), GFP_KERNEL);
  90         if (!gpio_charger) {
  91                 dev_err(&pdev->dev, "Failed to alloc driver structure\n");
  92                 return -ENOMEM;
  93         }
  94
  95         charger = &gpio_charger->charger;
  96
  97         charger->name = pdata->name ? pdata->name : "gpio-charger";
  98         charger->type = pdata->type;
  99         charger->properties = gpio_charger_properties;
 100         charger->num_properties = ARRAY_SIZE(gpio_charger_properties);
 101         charger->get_property = gpio_charger_get_property;
 102         charger->supplied_to = pdata->supplied_to;
 103         charger->num_supplicants = pdata->num_supplicants;
 104
 105         ret = gpio_request(pdata->gpio, dev_name(&pdev->dev));
 106         if (ret) {
 107                 dev_err(&pdev->dev, "Failed to request gpio pin: %d\n", ret);
 108                 goto err_free;
 109         }
 110         ret = gpio_direction_input(pdata->gpio);
 111         if (ret) {
 112                 dev_err(&pdev->dev, "Failed to set gpio to input: %d\n", ret);
 113                 goto err_gpio_free;
 114         }
 115
 116         gpio_charger->pdata = pdata;
 117
 118         ret = power_supply_register(&pdev->dev, charger);
 119         if (ret < 0) {
 120                 dev_err(&pdev->dev, "Failed to register power supply: %d\n",
 121                         ret);
 122                 goto err_gpio_free;
 123         }
 124
 125         irq = gpio_to_irq(pdata->gpio);
 126         if (irq > 0) {
 127                 ret = request_any_context_irq(irq, gpio_charger_irq,
 128                                 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
 129                                 dev_name(&pdev->dev), charger);
 130                 if (ret)
 131                         dev_warn(&pdev->dev, "Failed to request irq: %d\n", ret);
 132                 else
 133                         gpio_charger->irq = irq;
 134         }
 135
 136         platform_set_drvdata(pdev, gpio_charger);
 137
 138         return 0;
 139
 140 err_gpio_free:
 141         gpio_free(pdata->gpio);
 142 err_free:
 143         kfree(gpio_charger);
 144         return ret;
 145 }
 146
 147 static int __devexit gpio_charger_remove(struct platform_device *pdev)
 148 {
 149         struct gpio_charger *gpio_charger = platform_get_drvdata(pdev);
 150
 151         if (gpio_charger->irq)
 152                 free_irq(gpio_charger->irq, &gpio_charger->charger);
 153
 154         power_supply_unregister(&gpio_charger->charger);
 155
 156         gpio_free(gpio_charger->pdata->gpio);
 157
 158         platform_set_drvdata(pdev, NULL);
 159         kfree(gpio_charger);
 160
 161         return 0;
 162 }
 163
 164 static struct platform_driver gpio_charger_driver = {
 165         .probe = gpio_charger_probe,
 166         .remove = __devexit_p(gpio_charger_remove),
 167         .driver = {
 168                 .name = "gpio-charger",
 169                 .owner = THIS_MODULE,
 170         },
 171 };
 172
 173 static int __init gpio_charger_init(void)
 174 {
 175         return platform_driver_register(&gpio_charger_driver);
 176 }
 177 module_init(gpio_charger_init);
 178
 179 static void __exit gpio_charger_exit(void)
 180 {
 181         platform_driver_unregister(&gpio_charger_driver);
 182 }
 183 module_exit(gpio_charger_exit);
 184
 185 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 186 MODULE_DESCRIPTION("Driver for chargers which report their online status through a GPIO");
 187 MODULE_LICENSE("GPL");
 188 MODULE_ALIAS("platform:gpio-charger");