linux/drivers/power/gpio-charger.c
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   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
  28struct gpio_charger {
  29        const struct gpio_charger_platform_data *pdata;
  30        unsigned int irq;
  31
  32        struct power_supply charger;
  33};
  34
  35static 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
  44static inline struct gpio_charger *psy_to_gpio_charger(struct power_supply *psy)
  45{
  46        return container_of(psy, struct gpio_charger, charger);
  47}
  48
  49static 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
  67static enum power_supply_property gpio_charger_properties[] = {
  68        POWER_SUPPLY_PROP_ONLINE,
  69};
  70
  71static 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 = 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 < 0)
 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
 140err_gpio_free:
 141        gpio_free(pdata->gpio);
 142err_free:
 143        kfree(gpio_charger);
 144        return ret;
 145}
 146
 147static 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        kfree(gpio_charger);
 160
 161        return 0;
 162}
 163
 164#ifdef CONFIG_PM_SLEEP
 165static int gpio_charger_resume(struct device *dev)
 166{
 167        struct platform_device *pdev = to_platform_device(dev);
 168        struct gpio_charger *gpio_charger = platform_get_drvdata(pdev);
 169
 170        power_supply_changed(&gpio_charger->charger);
 171
 172        return 0;
 173}
 174#endif
 175
 176static SIMPLE_DEV_PM_OPS(gpio_charger_pm_ops, NULL, gpio_charger_resume);
 177
 178static struct platform_driver gpio_charger_driver = {
 179        .probe = gpio_charger_probe,
 180        .remove = gpio_charger_remove,
 181        .driver = {
 182                .name = "gpio-charger",
 183                .owner = THIS_MODULE,
 184                .pm = &gpio_charger_pm_ops,
 185        },
 186};
 187
 188module_platform_driver(gpio_charger_driver);
 189
 190MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 191MODULE_DESCRIPTION("Driver for chargers which report their online status through a GPIO");
 192MODULE_LICENSE("GPL");
 193MODULE_ALIAS("platform:gpio-charger");
 194
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