ams_delta_serio.c
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/*
* 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 <linux/module.h>
#include <asm/mach-types.h>
#include <mach/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 */
gpio_set_value(AMS_DELTA_GPIO_PIN_KEYBRD_PWR, 1);
return 0;
}
static void ams_delta_serio_close(struct serio *serio)
{
/* disable keyboard */
gpio_set_value(AMS_DELTA_GPIO_PIN_KEYBRD_PWR, 0);
}
static const struct gpio ams_delta_gpios[] __initconst_or_module = {
{
.gpio = AMS_DELTA_GPIO_PIN_KEYBRD_DATA,
.flags = GPIOF_DIR_IN,
.label = "serio-data",
},
{
.gpio = AMS_DELTA_GPIO_PIN_KEYBRD_CLK,
.flags = GPIOF_DIR_IN,
.label = "serio-clock",
},
{
.gpio = AMS_DELTA_GPIO_PIN_KEYBRD_PWR,
.flags = GPIOF_OUT_INIT_LOW,
.label = "serio-power",
},
{
.gpio = AMS_DELTA_GPIO_PIN_KEYBRD_DATAOUT,
.flags = GPIOF_OUT_INIT_LOW,
.label = "serio-dataout",
},
};
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_array(ams_delta_gpios,
ARRAY_SIZE(ams_delta_gpios));
if (err) {
pr_err("ams_delta_serio: Couldn't request gpio pins\n");
goto serio;
}
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;
}
/*
* 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.
*/
irq_set_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:
gpio_free_array(ams_delta_gpios,
ARRAY_SIZE(ams_delta_gpios));
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(gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK), 0);
gpio_free_array(ams_delta_gpios,
ARRAY_SIZE(ams_delta_gpios));
}
module_exit(ams_delta_serio_exit);