atkbd.c

at91_ps2_驱动~at91sam9261的IO口模拟PS2键盘驱动程序设计——最新

		case ATKBD_SCR_LEFT:
			hscroll = -1;
			break;
		case ATKBD_SCR_RIGHT:
			hscroll = 1;
			break;
		default:
			if (atkbd->release) {
				value = 0;
				atkbd->last = 0;
			} else if (!atkbd->softrepeat && test_bit(keycode, dev->key)) {
				/* Workaround Toshiba laptop multiple keypress */
				value = time_before(jiffies, atkbd->time) && atkbd->last == code ? 1 : 2;
			} else {
				value = 1;
				atkbd->last = code;
				atkbd->time = jiffies + msecs_to_jiffies(dev->rep[REP_DELAY]) / 2;
			}

			input_event(dev, EV_KEY, keycode, value);
			input_sync(dev);

			if (value && add_release_event) {
				input_report_key(dev, keycode, 0);
				input_sync(dev);
			}
	}

	if (atkbd->scroll) {
		if (click != -1)
			input_report_key(dev, BTN_MIDDLE, click);
		input_report_rel(dev, REL_WHEEL, scroll);
		input_report_rel(dev, REL_HWHEEL, hscroll);
		input_sync(dev);
	}

	atkbd->release = 0;
out:
	return IRQ_HANDLED;
}

static int atkbd_set_repeat_rate(struct atkbd *atkbd)		//重复速度
{
	const short period[32] =
		{ 33,  37,  42,  46,  50,  54,  58,  63,  67,  75,  83,  92, 100, 109, 116, 125,
		 133, 149, 167, 182, 200, 217, 232, 250, 270, 303, 333, 370, 400, 435, 470, 500 };
	const short delay[4] =
		{ 250, 500, 750, 1000 };

	struct input_dev *dev = atkbd->dev;
	unsigned char param;
	int i = 0, j = 0;

	while (i < ARRAY_SIZE(period) - 1 && period[i] < dev->rep[REP_PERIOD])
		i++;
	dev->rep[REP_PERIOD] = period[i];

	while (j < ARRAY_SIZE(delay) - 1 && delay[j] < dev->rep[REP_DELAY])
		j++;
	dev->rep[REP_DELAY] = delay[j];

	param = i | (j << 5);
	return ps2_command(&atkbd->ps2dev, &param, ATKBD_CMD_SETREP);
}

static int atkbd_set_leds(struct atkbd *atkbd)		//LED设置
{
	struct input_dev *dev = atkbd->dev;
	unsigned char param[2];

	param[0] = (test_bit(LED_SCROLLL, dev->led) ? 1 : 0)
		 | (test_bit(LED_NUML,    dev->led) ? 2 : 0)
		 | (test_bit(LED_CAPSL,   dev->led) ? 4 : 0);
	if (ps2_command(&atkbd->ps2dev, param, ATKBD_CMD_SETLEDS))
		return -1;

	if (atkbd->extra) {
		param[0] = 0;
		param[1] = (test_bit(LED_COMPOSE, dev->led) ? 0x01 : 0)
			 | (test_bit(LED_SLEEP,   dev->led) ? 0x02 : 0)
			 | (test_bit(LED_SUSPEND, dev->led) ? 0x04 : 0)
			 | (test_bit(LED_MISC,    dev->led) ? 0x10 : 0)
			 | (test_bit(LED_MUTE,    dev->led) ? 0x20 : 0);
		if (ps2_command(&atkbd->ps2dev, param, ATKBD_CMD_EX_SETLEDS))
			return -1;
	}

	return 0;
}

/*
 * atkbd_event_work() is used to complete processing of events that
 * can not be processed by input_event() which is often called from
 * interrupt context.
 * 过去习惯于完成事件处理 
 * 不能被处理用于输入事件 那些从中断环境
 */

static void atkbd_event_work(struct work_struct *work)
{
	struct atkbd *atkbd = container_of(work, struct atkbd, event_work);

	mutex_lock(&atkbd->event_mutex);

	if (test_and_clear_bit(ATKBD_LED_EVENT_BIT, &atkbd->event_mask))
		atkbd_set_leds(atkbd);

	if (test_and_clear_bit(ATKBD_REP_EVENT_BIT, &atkbd->event_mask))
		atkbd_set_repeat_rate(atkbd);

	mutex_unlock(&atkbd->event_mutex);
}

/*
 * Event callback from the input module. Events that change the state of
 * the hardware are processed here. If action can not be performed in
 * interrupt context it is offloaded to atkbd_event_work.
 * 返回来自输入模块，改变器件进程状态，如果功能 不能被中断环境下使用
 * 则卸下atkbd_event_work
 */

static int atkbd_event(struct input_dev *dev, unsigned int type, unsigned int code, int value)
{
	struct atkbd *atkbd = dev->private;

	if (!atkbd->write)
		return -1;

	switch (type) {

		case EV_LED:
			set_bit(ATKBD_LED_EVENT_BIT, &atkbd->event_mask);
			wmb();
			schedule_work(&atkbd->event_work);
			return 0;

		case EV_REP:

			if (!atkbd->softrepeat) {
				set_bit(ATKBD_REP_EVENT_BIT, &atkbd->event_mask);
				wmb();
				schedule_work(&atkbd->event_work);
			}

			return 0;
	}

	return -1;
}

/*
 * atkbd_enable() signals that interrupt handler is allowed to
 * generate input events.
 * 使能AT键盘信号，使中断被允许，产生输入事件
 */

static inline void atkbd_enable(struct atkbd *atkbd)
{
	serio_pause_rx(atkbd->ps2dev.serio);
	atkbd->enabled = 1;
	serio_continue_rx(atkbd->ps2dev.serio);
}

/*
 * atkbd_disable() tells input handler that all incoming data except
 * for ACKs and command response should be dropped.
 * 禁止atkbd
 */

static inline void atkbd_disable(struct atkbd *atkbd)
{
	serio_pause_rx(atkbd->ps2dev.serio);
	atkbd->enabled = 0;
	serio_continue_rx(atkbd->ps2dev.serio);
}

/*
 * atkbd_probe() probes for an AT keyboard on a serio port.
 */

static int atkbd_probe(struct atkbd *atkbd)
{
	struct ps2dev *ps2dev = &atkbd->ps2dev;
	unsigned char param[2];

/*
 * Some systems, where the bit-twiddling when testing the io-lines of the
 * controller may confuse the keyboard need a full reset of the keyboard. On
 * these systems the BIOS also usually doesn't do it for us.
 * 关于有些系统的控制I/O口抖动把键盘弄乱，需要重启
 */

	if (atkbd_reset)
		if (ps2_command(ps2dev, NULL, ATKBD_CMD_RESET_BAT))
			printk(KERN_WARNING "atkbd.c: keyboard reset failed on %s\n", ps2dev->serio->phys);

/*
 * Then we check the keyboard ID. We should get 0xab83 under normal conditions.
 * Some keyboards report different values, but the first byte is always 0xab or
 * 0xac. Some old AT keyboards don't report anything. If a mouse is connected, this
 * should make sure we don't try to set the LEDs on it.
 * 键盘ID正常情况下是0xab83，有些会不同但是允许前面为ab或者ac，
 * 老式键盘不会返回任何值，如果接的是鼠标确定我们不要设置LED，否则会报错
 */

	param[0] = param[1] = 0xa5;	/* initialize with invalid values初始化为适当的值 */
	if (ps2_command(ps2dev, param, ATKBD_CMD_GETID)) {

/*
 * If the get ID command failed, we check if we can at least set the LEDs on
 * the keyboard. This should work on every keyboard out there. It also turns
 * the LEDs off, which we want anyway.
 * 若ID返回出错，检查键盘的LED，学习从LED状态来检测键盘
 */
		param[0] = 0;
		if (ps2_command(ps2dev, param, ATKBD_CMD_SETLEDS))
			return -1;
		atkbd->id = 0xabba;
		return 0;
	}

	if (!ps2_is_keyboard_id(param[0]))
		return -1;

	atkbd->id = (param[0] << 8) | param[1];

	if (atkbd->id == 0xaca1 && atkbd->translated) {
		/*	ID 相等于（0xaca1 && 译码）*/
		printk(KERN_ERR "atkbd.c: NCD terminal keyboards are only supported on non-translating\n");
		printk(KERN_ERR "atkbd.c: controllers. Use i8042.direct=1 to disable translation.\n");
		return -1;
	}

	return 0;
}

/* atkbd_select_set checks if a keyboard has a working Set 3 support, and
 * sets it into that. Unfortunately there are keyboards that can be switched
 * to Set 3, but don't work well in that (BTC Multimedia ...)
 * 
 */

static int atkbd_select_set(struct atkbd *atkbd, int target_set, int allow_extra)
{
	struct ps2dev *ps2dev = &atkbd->ps2dev;
	unsigned char param[2];

	atkbd->extra = 0;
/*
 * For known special keyboards we can go ahead and set the correct set.
 * We check for NCD PS/2 Sun, NorthGate OmniKey 101 and
 * IBM RapidAccess / IBM EzButton / Chicony KBP-8993 keyboards.
 */

	if (atkbd->translated)
		return 2;

	if (atkbd->id == 0xaca1) {
		param[0] = 3;
		ps2_command(ps2dev, param, ATKBD_CMD_SSCANSET);
		return 3;
	}

	if (allow_extra) {
		param[0] = 0x71;
		if (!ps2_command(ps2dev, param, ATKBD_CMD_EX_ENABLE)) {
			atkbd->extra = 1;
			return 2;
		}
	}

	if (target_set != 3)
		return 2;

	if (!ps2_command(ps2dev, param, ATKBD_CMD_OK_GETID)) {
		atkbd->id = param[0] << 8 | param[1];
		return 2;
	}

	param[0] = 3;
	if (ps2_command(ps2dev, param, ATKBD_CMD_SSCANSET))
		return 2;

	param[0] = 0;
	if (ps2_command(ps2dev, param, ATKBD_CMD_GSCANSET))
		return 2;

	if (param[0] != 3) {
		param[0] = 2;
		if (ps2_command(ps2dev, param, ATKBD_CMD_SSCANSET))
		return 2;
	}

	ps2_command(ps2dev, param, ATKBD_CMD_SETALL_MBR);

	return 3;
}

/* atkbd激活  */
static int atkbd_activate(struct atkbd *atkbd)
{
	struct ps2dev *ps2dev = &atkbd->ps2dev;
	unsigned char param[1];

/*
 * Set the LEDs to a defined state.
 */

	param[0] = 0;
	if (ps2_command(ps2dev, param, ATKBD_CMD_SETLEDS))
		return -1;

/*
 * Set autorepeat to fastest possible.
 */

	param[0] = 0;
	if (ps2_command(ps2dev, param, ATKBD_CMD_SETREP))
		return -1;

/*
 * Enable the keyboard to receive keystrokes.
 * 使能键盘接收到按键
 */

	if (ps2_command(ps2dev, NULL, ATKBD_CMD_ENABLE)) {
		printk(KERN_ERR "atkbd.c: Failed to enable keyboard on %s\n",
			ps2dev->serio->phys);
		return -1;
	}

	return 0;
}

/*
 * atkbd_cleanup() restores the keyboard state so that BIOS is happy after a reboot
 * 
 */

static void atkbd_cleanup(struct serio *serio)
{
	struct atkbd *atkbd = serio_get_drvdata(serio);
	ps2_command(&atkbd->ps2dev, NULL, ATKBD_CMD_RESET_BAT);
}


/*
 * atkbd_disconnect() closes and frees.
 */

static void atkbd_disconnect(struct serio *serio)
{
	struct atkbd *atkbd = serio_get_drvdata(serio);

	atkbd_disable(atkbd);

	/* make sure we don't have a command in flight */
	synchronize_sched();  /* Allow atkbd_interrupt()s to complete. */
	flush_scheduled_work();

	sysfs_remove_group(&serio->dev.kobj, &atkbd_attribute_group);
	input_unregister_device(atkbd->dev);
	serio_close(serio);
	serio_set_drvdata(serio, NULL);
	kfree(atkbd);
}


/*
 * atkbd_set_keycode_table() initializes keyboard's keycode table
 * according to the selected scancode set
 * 键盘码映射表
 */

static void atkbd_set_keycode_table(struct atkbd *atkbd)
{
	int i, j;

	memset(atkbd->keycode, 0, sizeof(atkbd->keycode));//初始化键盘码映射表
	//将keycode所指向的某一块内存中的每个字节的内容全部设置为0指定的ASCII值,


	if (atkbd->translated) {
		for (i = 0; i < 128; i++) {
			atkbd->keycode[i] = atkbd_set2_keycode[atkbd_unxlate_table[i]];
			atkbd->keycode[i | 0x80] = atkbd_set2_keycode[atkbd_unxlate_table[i] | 0x80];
			if (atkbd->scroll)
				for (j = 0; j < ARRAY_SIZE(atkbd_scroll_keys); j++)
					if ((atkbd_unxlate_table[i] | 0x80) == atkbd_scroll_keys[j].set2)
						atkbd->keycode[i | 0x80] = atkbd_scroll_keys[j].keycode;
		}
	} else if (atkbd->set == 3) {
		memcpy(atkbd->keycode, atkbd_set3_keycode, sizeof(atkbd->keycode));
		//由src所指内存区域复制count个字节到dest所指内存区域。
　　	//src和dest所指内存区域不能重叠，函数返回指向dest的指针。
	} else {
		memcpy(atkbd->keycode, atkbd_set2_keycode, sizeof(atkbd->keycode));
		if (atkbd->scroll)
			for (i = 0; i < ARRAY_SIZE(atkbd_scroll_keys); i++)
				atkbd->keycode[atkbd_scroll_keys[i].set2] = atkbd_scroll_keys[i].keycode;
	}
	atkbd->keycode[atkbd_compat_scancode(atkbd, ATKBD_RET_HANGEUL)] = KEY_HANGUEL;
	atkbd->keycode[atkbd_compat_scancode(atkbd, ATKBD_RET_HANJA)] = KEY_HANJA;
}

/*
 * atkbd_set_device_attrs() sets up keyboard's input device structure
 * 建立起键盘输入设备的结构
 */

static void atkbd_set_device_attrs(struct atkbd *atkbd)
{
	struct input_dev *input_dev = atkbd->dev;
	int i;

	if (atkbd->extra)
		snprintf(atkbd->name,sizeof(atkbd->name),"AT Set 2 Extra keyboard");
	else
		snprintf(atkbd->name, sizeof(atkbd->name),
			 "AT %s Set %d keyboard",
			 atkbd->translated ? "Translated" : "Raw", atkbd->set);

	snprintf(atkbd->phys, sizeof(atkbd->phys),
		 "%s/input0", atkbd->ps2dev.serio->phys);

	input_dev->name = atkbd->name;
	input_dev->phys = atkbd->phys;
	input_dev->id.bustype = BUS_I8042;
	input_dev->id.vendor = 0x0001;
	input_dev->id.product = atkbd->translated ?1 : atkbd->set;
	input_dev->id.version = atkbd->id;
	input_dev->event = atkbd_event;
	input_dev->private = atkbd;
	input_dev->cdev.dev = &atkbd->ps2dev.serio->dev;
	input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_REP) | BIT(EV_MSC);

	if (atkbd->write) {
		input_dev->evbit[0] |= BIT(EV_LED);
		input_dev->ledbit[0] = BIT(LED_NUML) | BIT(LED_CAPSL) | BIT(LED_SCROLLL);
	}

	if (atkbd->extra)
		input_dev->ledbit[0] |= BIT(LED_COMPOSE) | BIT(LED_SUSPEND) |
					BIT(LED_SLEEP) | BIT(LED_MUTE) | BIT(LED_MISC);
	
	if (!atkbd->softrepeat) {
		input_dev->rep[REP_DELAY] = 250;
		input_dev->rep[REP_PERIOD] = 33;
	}

	input_dev->mscbit[0] = atkbd->softraw ? BIT(MSC_SCAN) : BIT(MSC_RAW) | BIT(MSC_SCAN);

	if (atkbd->scroll) {
		input_dev->evbit[0] |= BIT(EV_REL);
		input_dev->relbit[0] = BIT(REL_WHEEL) | BIT(REL_HWHEEL);
		set_bit(BTN_MIDDLE, input_dev->keybit);
	}

	input_dev->keycode = atkbd->keycode;
	input_dev->keycodesize = sizeof(unsigned char);
	input_dev->keycodemax = ARRAY_SIZE(atkbd_set2_keycode);

	for (i = 0; i < 512; i++)
		if (atkbd->keycode[i] && atkbd->keycode[i] < ATKBD_SPECIAL)
			set_bit(atkbd->keycode[i], input_dev->keybit);
}

/*
 * atkbd_connect() is called when the serio module finds an interface
 * that isn't handled yet by an appropriate device driver. We check if
 * there is an AT keyboard out there and if yes, we register ourselves
 * to the input module.
 * 当发现有键盘接入 调用atkbd_connect()
 */