drivers/usb/serial/ark3116.c

Source file repositories/reference/linux-study-clean/drivers/usb/serial/ark3116.c

File Facts

System
Linux kernel
Corpus path
drivers/usb/serial/ark3116.c
Extension
.c
Size
20097 bytes
Lines
735
Domain
Driver Families
Bucket
drivers/usb
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 ark3116_private {
	int			irda;	/* 1 for irda device */

	/* protects hw register updates */
	struct mutex		hw_lock;

	int			quot;	/* baudrate divisor */
	__u32			lcr;	/* line control register value */
	__u32			hcr;	/* handshake control register (0x8)
					 * value */
	__u32			mcr;	/* modem control register value */

	/* protects the status values below */
	spinlock_t		status_lock;
	__u32			msr;	/* modem status register value */
	__u32			lsr;	/* line status register value */
};

static int ark3116_write_reg(struct usb_serial *serial,
			     unsigned reg, __u8 val)
{
	int result;
	 /* 0xfe 0x40 are magic values taken from original driver */
	result = usb_control_msg(serial->dev,
				 usb_sndctrlpipe(serial->dev, 0),
				 0xfe, 0x40, val, reg,
				 NULL, 0, ARK_TIMEOUT);
	if (result)
		return result;

	return 0;
}

static int ark3116_read_reg(struct usb_serial *serial,
			    unsigned reg, unsigned char *buf)
{
	int result;
	/* 0xfe 0xc0 are magic values taken from original driver */
	result = usb_control_msg(serial->dev,
				 usb_rcvctrlpipe(serial->dev, 0),
				 0xfe, 0xc0, 0, reg,
				 buf, 1, ARK_TIMEOUT);
	if (result < 1) {
		dev_err(&serial->interface->dev,
				"failed to read register %u: %d\n",
				reg, result);
		if (result >= 0)
			result = -EIO;

		return result;
	}

	return 0;
}

static inline int calc_divisor(int bps)
{
	/* Original ark3116 made some exceptions in rounding here
	 * because windows did the same. Assume that is not really
	 * necessary.
	 * Crystal is 12MHz, probably because of USB, but we divide by 4?
	 */
	return (12000000 + 2*bps) / (4*bps);
}

static int ark3116_port_probe(struct usb_serial_port *port)
{
	struct usb_serial *serial = port->serial;
	struct ark3116_private *priv;

	priv = kzalloc_obj(*priv);
	if (!priv)
		return -ENOMEM;

	mutex_init(&priv->hw_lock);
	spin_lock_init(&priv->status_lock);

	priv->irda = is_irda(serial);

	usb_set_serial_port_data(port, priv);

	/* setup the hardware */
	ark3116_write_reg(serial, UART_IER, 0);
	/* disable DMA */
	ark3116_write_reg(serial, UART_FCR, 0);
	/* handshake control */
	priv->hcr = 0;
	ark3116_write_reg(serial, 0x8     , 0);
	/* modem control */
	priv->mcr = 0;

Annotation

Implementation Notes