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