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 */
32static 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
47static 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
54static 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
84static 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
94static struct platform_driver rb532_button_driver = {
95	.probe = rb532_button_probe,
96	.remove = rb532_button_remove,
97	.driver = {
98		.name = DRV_NAME,
99	},
100};
101module_platform_driver(rb532_button_driver);
102
103MODULE_AUTHOR("Phil Sutter <n0-1@freewrt.org>");
104MODULE_LICENSE("GPL");
105MODULE_DESCRIPTION("Support for S1 button on Routerboard 532");
106MODULE_ALIAS("platform:" DRV_NAME);
107