| 1 | |
| 2 | |
| 3 | * Support for the S1 button on Routerboard 532
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| 4 | *
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| 5 | * Copyright (C) 2009 Phil Sutter <[email protected]>
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| 6 |
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| 7 |
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| 8 | #include <linux/input.h>
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| 9 | #include <linux/module.h>
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| 10 | #include <linux/platform_device.h>
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| 11 | #include <linux/gpio/consumer.h>
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| 12 |
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| 13 | #include <asm/mach-rc32434/gpio.h>
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| 14 | #include <asm/mach-rc32434/rb.h>
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| 15 |
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| 16 | #define DRV_NAME "rb532-button"
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| 17 |
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| 18 | #define RB532_BTN_RATE 100
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| 19 | #define RB532_BTN_KSYM BTN_0
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| 20 |
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| 21 | |
| 22 | * struct rb532_button - RB532 button information
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| 23 | * @gpio: GPIO connected to the button
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| 24 |
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| 25 | struct rb532_button {
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| 26 | struct gpio_desc *gpio;
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| 27 | };
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| 28 |
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| 29 | |
| 30 | * pin is also used for uart input as alternate function, the
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| 31 | * operational modes must be switched first:
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| 32 | * 1) disable uart using set_latch_u5()
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| 33 | * 2) turn off alternate function implicitly through
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| 34 | * gpio_direction_input()
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| 35 | * 3) read the GPIO's current value
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| 36 | * 4) undo step 2 by enabling alternate function (in this
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| 37 | * mode the GPIO direction is fixed, so no change needed)
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| 38 | * 5) turn on uart again
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| 39 | * The GPIO value occurs to be inverted, so pin high means
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| 40 | * button is not pressed.
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| 41 |
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| 42 | static bool rb532_button_pressed(struct rb532_button *button)
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| 43 | {
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| 44 | int val;
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| 45 |
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| 46 | set_latch_u5(0, LO_FOFF);
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| 47 | gpiod_direction_input(button->gpio);
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| 48 |
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| 49 | val = gpiod_get_value(button->gpio);
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| 50 |
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| 51 | rb532_gpio_set_func(GPIO_BTN_S1);
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| 52 | set_latch_u5(LO_FOFF, 0);
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| 53 |
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| 54 | return val;
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| 55 | }
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| 56 |
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| 57 | static void rb532_button_poll(struct input_dev *input)
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| 58 | {
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| 59 | struct rb532_button *button = input_get_drvdata(input);
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| 60 |
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| 61 | input_report_key(input, RB532_BTN_KSYM, rb532_button_pressed(button));
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| 62 | input_sync(input);
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| 63 | }
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| 64 |
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| 65 | static int rb532_button_probe(struct platform_device *pdev)
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| 66 | {
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| 67 | struct rb532_button *button;
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| 68 | struct input_dev *input;
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| 69 | int error;
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| 70 |
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| 71 | button = devm_kzalloc(&pdev->dev, sizeof(*button), GFP_KERNEL);
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| 72 | if (!button)
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| 73 | return -ENOMEM;
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| 74 |
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| 75 | button->gpio = devm_gpiod_get(&pdev->dev, "button", GPIOD_IN);
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| 76 | if (IS_ERR(button->gpio))
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| 77 | return dev_err_probe(&pdev->dev, PTR_ERR(button->gpio),
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| 78 | "error getting button GPIO\n");
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| 79 |
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| 80 | input = devm_input_allocate_device(&pdev->dev);
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| 81 | if (!input)
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| 82 | return -ENOMEM;
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| 83 | input_set_drvdata(input, button);
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| 84 |
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| 85 | input->name = "rb532 button";
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| 86 | input->phys = "rb532/button0";
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| 87 | input->id.bustype = BUS_HOST;
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| 88 |
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| 89 | input_set_capability(input, EV_KEY, RB532_BTN_KSYM);
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| 90 |
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| 91 | error = input_setup_polling(input, rb532_button_poll);
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| 92 | if (error)
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| 93 | return error;
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| 94 |
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| 95 | input_set_poll_interval(input, RB532_BTN_RATE);
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| 96 |
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| 97 | error = input_register_device(input);
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| 98 | if (error)
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| 99 | return error;
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| 100 |
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| 101 | platform_set_drvdata(pdev, button);
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| 102 |
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| 103 | return 0;
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| 104 | }
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| 105 |
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| 106 | static struct platform_driver rb532_button_driver = {
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| 107 | .probe = rb532_button_probe,
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| 108 | .driver = {
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| 109 | .name = DRV_NAME,
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| 110 | },
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| 111 | };
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| 112 | module_platform_driver(rb532_button_driver);
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| 113 |
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| 114 | MODULE_AUTHOR("Phil Sutter <[email protected]>");
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| 115 | MODULE_LICENSE("GPL");
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| 116 | MODULE_DESCRIPTION("Support for S1 button on Routerboard 532");
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| 117 | MODULE_ALIAS("platform:" DRV_NAME);
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