drivers/input/joystick/spaceorb.c

Source file repositories/reference/linux-study-clean/drivers/input/joystick/spaceorb.c

File Facts

System
Linux kernel
Corpus path
drivers/input/joystick/spaceorb.c
Extension
.c
Size
5566 bytes
Lines
221
Domain
Driver Families
Bucket
drivers/input
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct spaceorb {
	struct input_dev *dev;
	int idx;
	unsigned char data[SPACEORB_MAX_LENGTH];
	char phys[32];
};

static unsigned char spaceorb_xor[] = "SpaceWare";

static unsigned char *spaceorb_errors[] = { "EEPROM storing 0 failed", "Receive queue overflow", "Transmit queue timeout",
		"Bad packet", "Power brown-out", "EEPROM checksum error", "Hardware fault" };

/*
 * spaceorb_process_packet() decodes packets the driver receives from the
 * SpaceOrb.
 */

static void spaceorb_process_packet(struct spaceorb *spaceorb)
{
	struct input_dev *dev = spaceorb->dev;
	unsigned char *data = spaceorb->data;
	unsigned char c = 0;
	int axes[6];
	int i;

	if (spaceorb->idx < 2) return;
	for (i = 0; i < spaceorb->idx; i++) c ^= data[i];
	if (c) return;

	switch (data[0]) {

		case 'R':				/* Reset packet */
			spaceorb->data[spaceorb->idx - 1] = 0;
			for (i = 1; i < spaceorb->idx && spaceorb->data[i] == ' '; i++);
			printk(KERN_INFO "input: %s [%s] is %s\n",
				 dev->name, spaceorb->data + i, spaceorb->phys);
			break;

		case 'D':				/* Ball + button data */
			if (spaceorb->idx != 12) return;
			for (i = 0; i < 9; i++) spaceorb->data[i+2] ^= spaceorb_xor[i];
			axes[0] = ( data[2]	 << 3) | (data[ 3] >> 4);
			axes[1] = ((data[3] & 0x0f) << 6) | (data[ 4] >> 1);
			axes[2] = ((data[4] & 0x01) << 9) | (data[ 5] << 2) | (data[4] >> 5);
			axes[3] = ((data[6] & 0x1f) << 5) | (data[ 7] >> 2);
			axes[4] = ((data[7] & 0x03) << 8) | (data[ 8] << 1) | (data[7] >> 6);
			axes[5] = ((data[9] & 0x3f) << 4) | (data[10] >> 3);
			for (i = 0; i < 6; i++)
				input_report_abs(dev, spaceorb_axes[i], axes[i] - ((axes[i] & 0x200) ? 1024 : 0));
			for (i = 0; i < 6; i++)
				input_report_key(dev, spaceorb_buttons[i], (data[1] >> i) & 1);
			break;

		case 'K':				/* Button data */
			if (spaceorb->idx != 5) return;
			for (i = 0; i < 6; i++)
				input_report_key(dev, spaceorb_buttons[i], (data[2] >> i) & 1);

			break;

		case 'E':				/* Error packet */
			if (spaceorb->idx != 4) return;
			printk(KERN_ERR "spaceorb: Device error. [ ");
			for (i = 0; i < 7; i++) if (data[1] & (1 << i)) printk("%s ", spaceorb_errors[i]);
			printk("]\n");
			break;
	}

	input_sync(dev);
}

static irqreturn_t spaceorb_interrupt(struct serio *serio,
		unsigned char data, unsigned int flags)
{
	struct spaceorb* spaceorb = serio_get_drvdata(serio);

	if (~data & 0x80) {
		if (spaceorb->idx) spaceorb_process_packet(spaceorb);
		spaceorb->idx = 0;
	}
	if (spaceorb->idx < SPACEORB_MAX_LENGTH)
		spaceorb->data[spaceorb->idx++] = data & 0x7f;
	return IRQ_HANDLED;
}

/*
 * spaceorb_disconnect() is the opposite of spaceorb_connect()
 */

static void spaceorb_disconnect(struct serio *serio)

Annotation

Implementation Notes