diff options
Diffstat (limited to 'drivers/switch/switch_gpio.c')
| -rw-r--r-- | drivers/switch/switch_gpio.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/drivers/switch/switch_gpio.c b/drivers/switch/switch_gpio.c new file mode 100644 index 000000000000..b5f98ca0b2e1 --- /dev/null +++ b/drivers/switch/switch_gpio.c @@ -0,0 +1,171 @@ +/* + * drivers/switch/switch_gpio.c + * + * Copyright (C) 2008 Google, Inc. + * Author: Mike Lockwood <lockwood@android.com> + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * 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. + * +*/ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/platform_device.h> +#include <linux/switch.h> +#include <linux/workqueue.h> +#include <linux/gpio.h> + +struct gpio_switch_data { + struct switch_dev sdev; + unsigned gpio; + const char *name_on; + const char *name_off; + const char *state_on; + const char *state_off; + int irq; + struct work_struct work; +}; + +static void gpio_switch_work(struct work_struct *work) +{ + int state; + struct gpio_switch_data *data = + container_of(work, struct gpio_switch_data, work); + + state = gpio_get_value(data->gpio); + switch_set_state(&data->sdev, state); +} + +static irqreturn_t gpio_irq_handler(int irq, void *dev_id) +{ + struct gpio_switch_data *switch_data = + (struct gpio_switch_data *)dev_id; + + schedule_work(&switch_data->work); + return IRQ_HANDLED; +} + +static ssize_t switch_gpio_print_state(struct switch_dev *sdev, char *buf) +{ + struct gpio_switch_data *switch_data = + container_of(sdev, struct gpio_switch_data, sdev); + const char *state; + if (switch_get_state(sdev)) + state = switch_data->state_on; + else + state = switch_data->state_off; + + if (state) + return sprintf(buf, "%s\n", state); + return -1; +} + +static int gpio_switch_probe(struct platform_device *pdev) +{ + struct gpio_switch_platform_data *pdata = pdev->dev.platform_data; + struct gpio_switch_data *switch_data; + int ret = 0; + + if (!pdata) + return -EBUSY; + + switch_data = kzalloc(sizeof(struct gpio_switch_data), GFP_KERNEL); + if (!switch_data) + return -ENOMEM; + + switch_data->sdev.name = pdata->name; + switch_data->gpio = pdata->gpio; + switch_data->name_on = pdata->name_on; + switch_data->name_off = pdata->name_off; + switch_data->state_on = pdata->state_on; + switch_data->state_off = pdata->state_off; + switch_data->sdev.print_state = switch_gpio_print_state; + + ret = switch_dev_register(&switch_data->sdev); + if (ret < 0) + goto err_switch_dev_register; + + ret = gpio_request(switch_data->gpio, pdev->name); + if (ret < 0) + goto err_request_gpio; + + ret = gpio_direction_input(switch_data->gpio); + if (ret < 0) + goto err_set_gpio_input; + + INIT_WORK(&switch_data->work, gpio_switch_work); + + switch_data->irq = gpio_to_irq(switch_data->gpio); + if (switch_data->irq < 0) { + ret = switch_data->irq; + goto err_detect_irq_num_failed; + } + + ret = request_irq(switch_data->irq, gpio_irq_handler, + IRQF_TRIGGER_LOW, pdev->name, switch_data); + if (ret < 0) + goto err_request_irq; + + /* Perform initial detection */ + gpio_switch_work(&switch_data->work); + + return 0; + +err_request_irq: +err_detect_irq_num_failed: +err_set_gpio_input: + gpio_free(switch_data->gpio); +err_request_gpio: + switch_dev_unregister(&switch_data->sdev); +err_switch_dev_register: + kfree(switch_data); + + return ret; +} + +static int __devexit gpio_switch_remove(struct platform_device *pdev) +{ + struct gpio_switch_data *switch_data = platform_get_drvdata(pdev); + + cancel_work_sync(&switch_data->work); + gpio_free(switch_data->gpio); + switch_dev_unregister(&switch_data->sdev); + kfree(switch_data); + + return 0; +} + +static struct platform_driver gpio_switch_driver = { + .probe = gpio_switch_probe, + .remove = __devexit_p(gpio_switch_remove), + .driver = { + .name = "switch-gpio", + .owner = THIS_MODULE, + }, +}; + +static int __init gpio_switch_init(void) +{ + return platform_driver_register(&gpio_switch_driver); +} + +static void __exit gpio_switch_exit(void) +{ + platform_driver_unregister(&gpio_switch_driver); +} + +module_init(gpio_switch_init); +module_exit(gpio_switch_exit); + +MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>"); +MODULE_DESCRIPTION("GPIO Switch driver"); +MODULE_LICENSE("GPL"); |