drivers/input/serio/ams_delta_serio.c

Source file repositories/reference/linux-study-clean/drivers/input/serio/ams_delta_serio.c

File Facts

System
Linux kernel
Corpus path
drivers/input/serio/ams_delta_serio.c
Extension
.c
Size
5134 bytes
Lines
191
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 ams_delta_serio {
	struct serio *serio;
	struct regulator *vcc;
	unsigned int *fiq_buffer;
};

static int check_data(struct serio *serio, int data)
{
	int i, parity = 0;

	/* check valid stop bit */
	if (!(data & 0x400)) {
		dev_warn(&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(&serio->dev,
			 "parity 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)
{
	struct ams_delta_serio *priv = dev_id;
	int *circ_buff = &priv->fiq_buffer[FIQ_CIRC_BUFF];
	int data, dfl;
	u8 scancode;

	priv->fiq_buffer[FIQ_IRQ_PEND] = 0;

	/*
	 * Read data from the circular buffer, check it
	 * and then pass it on the serio
	 */
	while (priv->fiq_buffer[FIQ_KEYS_CNT] > 0) {

		data = circ_buff[priv->fiq_buffer[FIQ_HEAD_OFFSET]++];
		priv->fiq_buffer[FIQ_KEYS_CNT]--;
		if (priv->fiq_buffer[FIQ_HEAD_OFFSET] ==
		    priv->fiq_buffer[FIQ_BUF_LEN])
			priv->fiq_buffer[FIQ_HEAD_OFFSET] = 0;

		dfl = check_data(priv->serio, data);
		scancode = (u8) (data >> 1) & 0xFF;
		serio_interrupt(priv->serio, scancode, dfl);
	}
	return IRQ_HANDLED;
}

static int ams_delta_serio_open(struct serio *serio)
{
	struct ams_delta_serio *priv = serio->port_data;

	/* enable keyboard */
	return regulator_enable(priv->vcc);
}

static void ams_delta_serio_close(struct serio *serio)
{
	struct ams_delta_serio *priv = serio->port_data;

	/* disable keyboard */
	regulator_disable(priv->vcc);
}

static int ams_delta_serio_init(struct platform_device *pdev)
{
	struct ams_delta_serio *priv;
	struct serio *serio;
	int irq, err;

	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	priv->fiq_buffer = pdev->dev.platform_data;
	if (!priv->fiq_buffer)
		return -EINVAL;

	priv->vcc = devm_regulator_get(&pdev->dev, "vcc");
	if (IS_ERR(priv->vcc)) {

Annotation

Implementation Notes