2 * Amstrad E3 (Delta) keyboard port driver
4 * Copyright (c) 2006 Matt Callow
5 * Copyright (c) 2010 Janusz Krzysztofik
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 as published by
9 * the Free Software Foundation.
11 * Thanks to Cliff Lawson for his help
13 * The Amstrad Delta keyboard (aka mailboard) uses normal PC-AT style serial
14 * transmission. The keyboard port is formed of two GPIO lines, for clock
15 * and data. Due to strict timing requirements of the interface,
16 * the serial data stream is read and processed by a FIQ handler.
17 * The resulting words are fetched by this driver from a circular buffer.
19 * Standard AT keyboard driver (atkbd) is used for handling the keyboard data.
20 * However, when used with the E3 mailboard that producecs non-standard
21 * scancodes, a custom key table must be prepared and loaded from userspace.
23 #include <linux/gpio.h>
24 #include <linux/irq.h>
25 #include <linux/serio.h>
26 #include <linux/slab.h>
27 #include <linux/module.h>
29 #include <asm/mach-types.h>
30 #include <plat/board-ams-delta.h>
32 #include <mach/ams-delta-fiq.h>
34 MODULE_AUTHOR("Matt Callow");
35 MODULE_DESCRIPTION("AMS Delta (E3) keyboard port driver");
36 MODULE_LICENSE("GPL");
38 static struct serio *ams_delta_serio;
40 static int check_data(int data)
44 /* check valid stop bit */
45 if (!(data & 0x400)) {
46 dev_warn(&ams_delta_serio->dev,
47 "invalid stop bit, data=0x%X\n",
51 /* calculate the parity */
52 for (i = 1; i < 10; i++) {
56 /* it should be odd */
57 if (!(parity & 0x01)) {
58 dev_warn(&ams_delta_serio->dev,
59 "paritiy check failed, data=0x%X parity=0x%X\n",
66 static irqreturn_t ams_delta_serio_interrupt(int irq, void *dev_id)
68 int *circ_buff = &fiq_buffer[FIQ_CIRC_BUFF];
72 fiq_buffer[FIQ_IRQ_PEND] = 0;
75 * Read data from the circular buffer, check it
76 * and then pass it on the serio
78 while (fiq_buffer[FIQ_KEYS_CNT] > 0) {
80 data = circ_buff[fiq_buffer[FIQ_HEAD_OFFSET]++];
81 fiq_buffer[FIQ_KEYS_CNT]--;
82 if (fiq_buffer[FIQ_HEAD_OFFSET] == fiq_buffer[FIQ_BUF_LEN])
83 fiq_buffer[FIQ_HEAD_OFFSET] = 0;
85 dfl = check_data(data);
86 scancode = (u8) (data >> 1) & 0xFF;
87 serio_interrupt(ams_delta_serio, scancode, dfl);
92 static int ams_delta_serio_open(struct serio *serio)
95 ams_delta_latch2_write(AMD_DELTA_LATCH2_KEYBRD_PWR,
96 AMD_DELTA_LATCH2_KEYBRD_PWR);
101 static void ams_delta_serio_close(struct serio *serio)
103 /* disable keyboard */
104 ams_delta_latch2_write(AMD_DELTA_LATCH2_KEYBRD_PWR, 0);
107 static int __init ams_delta_serio_init(void)
111 if (!machine_is_ams_delta())
114 ams_delta_serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
115 if (!ams_delta_serio)
118 ams_delta_serio->id.type = SERIO_8042;
119 ams_delta_serio->open = ams_delta_serio_open;
120 ams_delta_serio->close = ams_delta_serio_close;
121 strlcpy(ams_delta_serio->name, "AMS DELTA keyboard adapter",
122 sizeof(ams_delta_serio->name));
123 strlcpy(ams_delta_serio->phys, "GPIO/serio0",
124 sizeof(ams_delta_serio->phys));
126 err = gpio_request(AMS_DELTA_GPIO_PIN_KEYBRD_DATA, "serio-data");
128 pr_err("ams_delta_serio: Couldn't request gpio pin for data\n");
131 gpio_direction_input(AMS_DELTA_GPIO_PIN_KEYBRD_DATA);
133 err = gpio_request(AMS_DELTA_GPIO_PIN_KEYBRD_CLK, "serio-clock");
135 pr_err("ams_delta_serio: couldn't request gpio pin for clock\n");
138 gpio_direction_input(AMS_DELTA_GPIO_PIN_KEYBRD_CLK);
140 err = request_irq(gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK),
141 ams_delta_serio_interrupt, IRQ_TYPE_EDGE_RISING,
142 "ams-delta-serio", 0);
144 pr_err("ams_delta_serio: couldn't request gpio interrupt %d\n",
145 gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK));
149 * Since GPIO register handling for keyboard clock pin is performed
150 * at FIQ level, switch back from edge to simple interrupt handler
151 * to avoid bad interaction.
153 irq_set_handler(gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK),
156 serio_register_port(ams_delta_serio);
157 dev_info(&ams_delta_serio->dev, "%s\n", ams_delta_serio->name);
161 gpio_free(AMS_DELTA_GPIO_PIN_KEYBRD_CLK);
163 gpio_free(AMS_DELTA_GPIO_PIN_KEYBRD_DATA);
165 kfree(ams_delta_serio);
168 module_init(ams_delta_serio_init);
170 static void __exit ams_delta_serio_exit(void)
172 serio_unregister_port(ams_delta_serio);
173 free_irq(OMAP_GPIO_IRQ(AMS_DELTA_GPIO_PIN_KEYBRD_CLK), 0);
174 gpio_free(AMS_DELTA_GPIO_PIN_KEYBRD_CLK);
175 gpio_free(AMS_DELTA_GPIO_PIN_KEYBRD_DATA);
177 module_exit(ams_delta_serio_exit);