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_cansleep(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 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 = devm_kzalloc(&pdev->dev, sizeof(*gpio_charger),
  90                                         GFP_KERNEL);
  91         if (!gpio_charger) {
  92                 dev_err(&pdev->dev, "Failed to alloc driver structure\n");
  93                 return -ENOMEM;
  94         }
  95
  96         charger = &gpio_charger->charger;
  97
  98         charger->name = pdata->name ? pdata->name : "gpio-charger";
  99         charger->type = pdata->type;
 100         charger->properties = gpio_charger_properties;
 101         charger->num_properties = ARRAY_SIZE(gpio_charger_properties);
 102         charger->get_property = gpio_charger_get_property;
 103         charger->supplied_to = pdata->supplied_to;
 104         charger->num_supplicants = pdata->num_supplicants;
 105
 106         ret = gpio_request(pdata->gpio, dev_name(&pdev->dev));
 107         if (ret) {
 108                 dev_err(&pdev->dev, "Failed to request gpio pin: %d\n", ret);
 109                 goto err_free;
 110         }
 111         ret = gpio_direction_input(pdata->gpio);
 112         if (ret) {
 113                 dev_err(&pdev->dev, "Failed to set gpio to input: %d\n", ret);
 114                 goto err_gpio_free;
 115         }
 116
 117         gpio_charger->pdata = pdata;
 118
 119         ret = power_supply_register(&pdev->dev, charger);
 120         if (ret < 0) {
 121                 dev_err(&pdev->dev, "Failed to register power supply: %d\n",
 122                         ret);
 123                 goto err_gpio_free;
 124         }
 125
 126         irq = gpio_to_irq(pdata->gpio);
 127         if (irq > 0) {
 128                 ret = request_any_context_irq(irq, gpio_charger_irq,
 129                                 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
 130                                 dev_name(&pdev->dev), charger);
 131                 if (ret < 0)
 132                         dev_warn(&pdev->dev, "Failed to request irq: %d\n", ret);
 133                 else
 134                         gpio_charger->irq = irq;
 135         }
 136
 137         platform_set_drvdata(pdev, gpio_charger);
 138
 139         return 0;
 140
 141 err_gpio_free:
 142         gpio_free(pdata->gpio);
 143 err_free:
 144         return ret;
 145 }
 146
 147 static int 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
 160         return 0;
 161 }
 162
 163 #ifdef CONFIG_PM_SLEEP
 164 static int gpio_charger_resume(struct device *dev)
 165 {
 166         struct platform_device *pdev = to_platform_device(dev);
 167         struct gpio_charger *gpio_charger = platform_get_drvdata(pdev);
 168
 169         power_supply_changed(&gpio_charger->charger);
 170
 171         return 0;
 172 }
 173 #endif
 174
 175 static SIMPLE_DEV_PM_OPS(gpio_charger_pm_ops, NULL, gpio_charger_resume);
 176
 177 static struct platform_driver gpio_charger_driver = {
 178         .probe = gpio_charger_probe,
 179         .remove = gpio_charger_remove,
 180         .driver = {
 181                 .name = "gpio-charger",
 182                 .owner = THIS_MODULE,
 183                 .pm = &gpio_charger_pm_ops,
 184         },
 185 };
 186
 187 module_platform_driver(gpio_charger_driver);
 188
 189 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 190 MODULE_DESCRIPTION("Driver for chargers which report their online status through a GPIO");
 191 MODULE_LICENSE("GPL");
 192 MODULE_ALIAS("platform:gpio-charger");