LXR linux/drivers/input/serio/ams_delta

   1/*
   2 *  Amstrad E3 (Delta) keyboard port driver
   3 *
   4 *  Copyright (c) 2006 Matt Callow
   5 *  Copyright (c) 2010 Janusz Krzysztofik
   6 *
   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.
  10 *
  11 * Thanks to Cliff Lawson for his help
  12 *
  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.
  18 *
  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.
  22 */
  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>
  28
  29#include <asm/mach-types.h>
  30#include <mach/board-ams-delta.h>
  31
  32#include <mach/ams-delta-fiq.h>
  33
  34MODULE_AUTHOR("Matt Callow");
  35MODULE_DESCRIPTION("AMS Delta (E3) keyboard port driver");
  36MODULE_LICENSE("GPL");
  37
  38static struct serio *ams_delta_serio;
  39
  40static int check_data(int data)
  41{
  42        int i, parity = 0;
  43
  44        /* check valid stop bit */
  45        if (!(data & 0x400)) {
  46                dev_warn(&ams_delta_serio->dev,
  47                                "invalid stop bit, data=0x%X\n",
  48                                data);
  49                return SERIO_FRAME;
  50        }
  51        /* calculate the parity */
  52        for (i = 1; i < 10; i++) {
  53                if (data & (1 << i))
  54                        parity++;
  55        }
  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",
  60                                data, parity);
  61                return SERIO_PARITY;
  62        }
  63        return 0;
  64}
  65
  66static irqreturn_t ams_delta_serio_interrupt(int irq, void *dev_id)
  67{
  68        int *circ_buff = &fiq_buffer[FIQ_CIRC_BUFF];
  69        int data, dfl;
  70        u8 scancode;
  71
  72        fiq_buffer[FIQ_IRQ_PEND] = 0;
  73
  74        /*
  75         * Read data from the circular buffer, check it
  76         * and then pass it on the serio
  77         */
  78        while (fiq_buffer[FIQ_KEYS_CNT] > 0) {
  79
  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;
  84
  85                dfl = check_data(data);
  86                scancode = (u8) (data >> 1) & 0xFF;
  87                serio_interrupt(ams_delta_serio, scancode, dfl);
  88        }
  89        return IRQ_HANDLED;
  90}
  91
  92static int ams_delta_serio_open(struct serio *serio)
  93{
  94        /* enable keyboard */
  95        gpio_set_value(AMS_DELTA_GPIO_PIN_KEYBRD_PWR, 1);
  96
  97        return 0;
  98}
  99
 100static void ams_delta_serio_close(struct serio *serio)
 101{
 102        /* disable keyboard */
 103        gpio_set_value(AMS_DELTA_GPIO_PIN_KEYBRD_PWR, 0);
 104}
 105
 106static const struct gpio ams_delta_gpios[] __initconst_or_module = {
 107        {
 108                .gpio   = AMS_DELTA_GPIO_PIN_KEYBRD_DATA,
 109                .flags  = GPIOF_DIR_IN,
 110                .label  = "serio-data",
 111        },
 112        {
 113                .gpio   = AMS_DELTA_GPIO_PIN_KEYBRD_CLK,
 114                .flags  = GPIOF_DIR_IN,
 115                .label  = "serio-clock",
 116        },
 117        {
 118                .gpio   = AMS_DELTA_GPIO_PIN_KEYBRD_PWR,
 119                .flags  = GPIOF_OUT_INIT_LOW,
 120                .label  = "serio-power",
 121        },
 122        {
 123                .gpio   = AMS_DELTA_GPIO_PIN_KEYBRD_DATAOUT,
 124                .flags  = GPIOF_OUT_INIT_LOW,
 125                .label  = "serio-dataout",
 126        },
 127};
 128
 129static int __init ams_delta_serio_init(void)
 130{
 131        int err;
 132
 133        if (!machine_is_ams_delta())
 134                return -ENODEV;
 135
 136        ams_delta_serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
 137        if (!ams_delta_serio)
 138                return -ENOMEM;
 139
 140        ams_delta_serio->id.type = SERIO_8042;
 141        ams_delta_serio->open = ams_delta_serio_open;
 142        ams_delta_serio->close = ams_delta_serio_close;
 143        strlcpy(ams_delta_serio->name, "AMS DELTA keyboard adapter",
 144                        sizeof(ams_delta_serio->name));
 145        strlcpy(ams_delta_serio->phys, "GPIO/serio0",
 146                        sizeof(ams_delta_serio->phys));
 147
 148        err = gpio_request_array(ams_delta_gpios,
 149                                ARRAY_SIZE(ams_delta_gpios));
 150        if (err) {
 151                pr_err("ams_delta_serio: Couldn't request gpio pins\n");
 152                goto serio;
 153        }
 154
 155        err = request_irq(gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK),
 156                        ams_delta_serio_interrupt, IRQ_TYPE_EDGE_RISING,
 157                        "ams-delta-serio", 0);
 158        if (err < 0) {
 159                pr_err("ams_delta_serio: couldn't request gpio interrupt %d\n",
 160                                gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK));
 161                goto gpio;
 162        }
 163        /*
 164         * Since GPIO register handling for keyboard clock pin is performed
 165         * at FIQ level, switch back from edge to simple interrupt handler
 166         * to avoid bad interaction.
 167         */
 168        irq_set_handler(gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK),
 169                        handle_simple_irq);
 170
 171        serio_register_port(ams_delta_serio);
 172        dev_info(&ams_delta_serio->dev, "%s\n", ams_delta_serio->name);
 173
 174        return 0;
 175gpio:
 176        gpio_free_array(ams_delta_gpios,
 177                        ARRAY_SIZE(ams_delta_gpios));
 178serio:
 179        kfree(ams_delta_serio);
 180        return err;
 181}
 182module_init(ams_delta_serio_init);
 183
 184static void __exit ams_delta_serio_exit(void)
 185{
 186        serio_unregister_port(ams_delta_serio);
 187        free_irq(gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK), 0);
 188        gpio_free_array(ams_delta_gpios,
 189                        ARRAY_SIZE(ams_delta_gpios));
 190}
 191module_exit(ams_delta_serio_exit);
 192