1 /* 2 * Support for the S1 button on Routerboard 532 3 * 4 * Copyright (C) 2009 Phil Sutter <n0-1@freewrt.org> 5 */ 6 7 #include <linux/input-polldev.h> 8 #include <linux/module.h> 9 #include <linux/platform_device.h> 10 11 #include <asm/mach-rc32434/gpio.h> 12 #include <asm/mach-rc32434/rb.h> 13 14 #define DRV_NAME "rb532-button" 15 16 #define RB532_BTN_RATE 100 /* msec */ 17 #define RB532_BTN_KSYM BTN_0 18 19 /* The S1 button state is provided by GPIO pin 1. But as this 20 * pin is also used for uart input as alternate function, the 21 * operational modes must be switched first: 22 * 1) disable uart using set_latch_u5() 23 * 2) turn off alternate function implicitly through 24 * gpio_direction_input() 25 * 3) read the GPIO's current value 26 * 4) undo step 2 by enabling alternate function (in this 27 * mode the GPIO direction is fixed, so no change needed) 28 * 5) turn on uart again 29 * The GPIO value occurs to be inverted, so pin high means 30 * button is not pressed. 31 */ 32 static bool rb532_button_pressed(void) 33 { 34 int val; 35 36 set_latch_u5(0, LO_FOFF); 37 gpio_direction_input(GPIO_BTN_S1); 38 39 val = gpio_get_value(GPIO_BTN_S1); 40 41 rb532_gpio_set_func(GPIO_BTN_S1); 42 set_latch_u5(LO_FOFF, 0); 43 44 return !val; 45 } 46 47 static void rb532_button_poll(struct input_polled_dev *poll_dev) 48 { 49 input_report_key(poll_dev->input, RB532_BTN_KSYM, 50 rb532_button_pressed()); 51 input_sync(poll_dev->input); 52 } 53 54 static int rb532_button_probe(struct platform_device *pdev) 55 { 56 struct input_polled_dev *poll_dev; 57 int error; 58 59 poll_dev = input_allocate_polled_device(); 60 if (!poll_dev) 61 return -ENOMEM; 62 63 poll_dev->poll = rb532_button_poll; 64 poll_dev->poll_interval = RB532_BTN_RATE; 65 66 poll_dev->input->name = "rb532 button"; 67 poll_dev->input->phys = "rb532/button0"; 68 poll_dev->input->id.bustype = BUS_HOST; 69 poll_dev->input->dev.parent = &pdev->dev; 70 71 dev_set_drvdata(&pdev->dev, poll_dev); 72 73 input_set_capability(poll_dev->input, EV_KEY, RB532_BTN_KSYM); 74 75 error = input_register_polled_device(poll_dev); 76 if (error) { 77 input_free_polled_device(poll_dev); 78 return error; 79 } 80 81 return 0; 82 } 83 84 static int rb532_button_remove(struct platform_device *pdev) 85 { 86 struct input_polled_dev *poll_dev = dev_get_drvdata(&pdev->dev); 87 88 input_unregister_polled_device(poll_dev); 89 input_free_polled_device(poll_dev); 90 91 return 0; 92 } 93 94 static struct platform_driver rb532_button_driver = { 95 .probe = rb532_button_probe, 96 .remove = rb532_button_remove, 97 .driver = { 98 .name = DRV_NAME, 99 .owner = THIS_MODULE, 100 }, 101 }; 102 module_platform_driver(rb532_button_driver); 103 104 MODULE_AUTHOR("Phil Sutter <n0-1@freewrt.org>"); 105 MODULE_LICENSE("GPL"); 106 MODULE_DESCRIPTION("Support for S1 button on Routerboard 532"); 107 MODULE_ALIAS("platform:" DRV_NAME); 108