summaryrefslogtreecommitdiffstats
path: root/drivers/input/serio/ams_delta_serio.c
blob: ebe9553256777aeb156e12247e1fa5ad91b9b8b9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
/*
 *  Amstrad E3 (Delta) keyboard port driver
 *
 *  Copyright (c) 2006 Matt Callow
 *  Copyright (c) 2010 Janusz Krzysztofik
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * Thanks to Cliff Lawson for his help
 *
 * The Amstrad Delta keyboard (aka mailboard) uses normal PC-AT style serial
 * transmission.  The keyboard port is formed of two GPIO lines, for clock
 * and data.  Due to strict timing requirements of the interface,
 * the serial data stream is read and processed by a FIQ handler.
 * The resulting words are fetched by this driver from a circular buffer.
 *
 * Standard AT keyboard driver (atkbd) is used for handling the keyboard data.
 * However, when used with the E3 mailboard that producecs non-standard
 * scancodes, a custom key table must be prepared and loaded from userspace.
 */
#include <linux/gpio.h>
#include <linux/irq.h>
#include <linux/serio.h>
#include <linux/slab.h>

#include <asm/mach-types.h>
#include <plat/board-ams-delta.h>

#include <mach/ams-delta-fiq.h>

MODULE_AUTHOR("Matt Callow");
MODULE_DESCRIPTION("AMS Delta (E3) keyboard port driver");
MODULE_LICENSE("GPL");

static struct serio *ams_delta_serio;

static int check_data(int data)
{
	int i, parity = 0;

	/* check valid stop bit */
	if (!(data & 0x400)) {
		dev_warn(&ams_delta_serio->dev,
				"invalid stop bit, data=0x%X\n",
				data);
		return SERIO_FRAME;
	}
	/* calculate the parity */
	for (i = 1; i < 10; i++) {
		if (data & (1 << i))
			parity++;
	}
	/* it should be odd */
	if (!(parity & 0x01)) {
		dev_warn(&ams_delta_serio->dev,
				"paritiy check failed, data=0x%X parity=0x%X\n",
				data, parity);
		return SERIO_PARITY;
	}
	return 0;
}

static irqreturn_t ams_delta_serio_interrupt(int irq, void *dev_id)
{
	int *circ_buff = &fiq_buffer[FIQ_CIRC_BUFF];
	int data, dfl;
	u8 scancode;

	fiq_buffer[FIQ_IRQ_PEND] = 0;

	/*
	 * Read data from the circular buffer, check it
	 * and then pass it on the serio
	 */
	while (fiq_buffer[FIQ_KEYS_CNT] > 0) {

		data = circ_buff[fiq_buffer[FIQ_HEAD_OFFSET]++];
		fiq_buffer[FIQ_KEYS_CNT]--;
		if (fiq_buffer[FIQ_HEAD_OFFSET] == fiq_buffer[FIQ_BUF_LEN])
			fiq_buffer[FIQ_HEAD_OFFSET] = 0;

		dfl = check_data(data);
		scancode = (u8) (data >> 1) & 0xFF;
		serio_interrupt(ams_delta_serio, scancode, dfl);
	}
	return IRQ_HANDLED;
}

static int ams_delta_serio_open(struct serio *serio)
{
	/* enable keyboard */
	ams_delta_latch2_write(AMD_DELTA_LATCH2_KEYBRD_PWR,
			AMD_DELTA_LATCH2_KEYBRD_PWR);

	return 0;
}

static void ams_delta_serio_close(struct serio *serio)
{
	/* disable keyboard */
	ams_delta_latch2_write(AMD_DELTA_LATCH2_KEYBRD_PWR, 0);
}

static int __init ams_delta_serio_init(void)
{
	int err;

	if (!machine_is_ams_delta())
		return -ENODEV;

	ams_delta_serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
	if (!ams_delta_serio)
		return -ENOMEM;

	ams_delta_serio->id.type = SERIO_8042;
	ams_delta_serio->open = ams_delta_serio_open;
	ams_delta_serio->close = ams_delta_serio_close;
	strlcpy(ams_delta_serio->name, "AMS DELTA keyboard adapter",
			sizeof(ams_delta_serio->name));
	strlcpy(ams_delta_serio->phys, "GPIO/serio0",
			sizeof(ams_delta_serio->phys));

	err = gpio_request(AMS_DELTA_GPIO_PIN_KEYBRD_DATA, "serio-data");
	if (err) {
		pr_err("ams_delta_serio: Couldn't request gpio pin for data\n");
		goto serio;
	}
	gpio_direction_input(AMS_DELTA_GPIO_PIN_KEYBRD_DATA);

	err = gpio_request(AMS_DELTA_GPIO_PIN_KEYBRD_CLK, "serio-clock");
	if (err) {
		pr_err("ams_delta_serio: couldn't request gpio pin for clock\n");
		goto gpio_data;
	}
	gpio_direction_input(AMS_DELTA_GPIO_PIN_KEYBRD_CLK);

	err = request_irq(gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK),
			ams_delta_serio_interrupt, IRQ_TYPE_EDGE_RISING,
			"ams-delta-serio", 0);
	if (err < 0) {
		pr_err("ams_delta_serio: couldn't request gpio interrupt %d\n",
				gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK));
		goto gpio_clk;
	}
	/*
	 * Since GPIO register handling for keyboard clock pin is performed
	 * at FIQ level, switch back from edge to simple interrupt handler
	 * to avoid bad interaction.
	 */
	set_irq_handler(gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK),
			handle_simple_irq);

	serio_register_port(ams_delta_serio);
	dev_info(&ams_delta_serio->dev, "%s\n", ams_delta_serio->name);

	return 0;
gpio_clk:
	gpio_free(AMS_DELTA_GPIO_PIN_KEYBRD_CLK);
gpio_data:
	gpio_free(AMS_DELTA_GPIO_PIN_KEYBRD_DATA);
serio:
	kfree(ams_delta_serio);
	return err;
}
module_init(ams_delta_serio_init);

static void __exit ams_delta_serio_exit(void)
{
	serio_unregister_port(ams_delta_serio);
	free_irq(OMAP_GPIO_IRQ(AMS_DELTA_GPIO_PIN_KEYBRD_CLK), 0);
	gpio_free(AMS_DELTA_GPIO_PIN_KEYBRD_CLK);
	gpio_free(AMS_DELTA_GPIO_PIN_KEYBRD_DATA);
}
module_exit(ams_delta_serio_exit);