drivers/i2c/busses/i2c-viapro.c

Source file repositories/reference/linux-study-clean/drivers/i2c/busses/i2c-viapro.c

File Facts

System
Linux kernel
Corpus path
drivers/i2c/busses/i2c-viapro.c
Extension
.c
Size
13872 bytes
Lines
497
Domain
Driver Families
Bucket
drivers/i2c
Inferred role
Driver Families: operation-table or driver-model contract
Status
pattern 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

static struct pci_driver vt596_driver;
static struct i2c_adapter vt596_adapter;

#define FEATURE_I2CBLOCK	(1<<0)
static unsigned int vt596_features;

#ifdef DEBUG
static void vt596_dump_regs(const char *msg, u8 size)
{
	dev_dbg(&vt596_adapter.dev, "%s: STS=%02x CNT=%02x CMD=%02x ADD=%02x "
		"DAT=%02x,%02x\n", msg, inb_p(SMBHSTSTS), inb_p(SMBHSTCNT),
		inb_p(SMBHSTCMD), inb_p(SMBHSTADD), inb_p(SMBHSTDAT0),
		inb_p(SMBHSTDAT1));

	if (size == VT596_BLOCK_DATA
	 || size == VT596_I2C_BLOCK_DATA) {
		int i;

		dev_dbg(&vt596_adapter.dev, "BLK=");
		for (i = 0; i < I2C_SMBUS_BLOCK_MAX / 2; i++)
			printk("%02x,", inb_p(SMBBLKDAT));
		printk("\n");
		dev_dbg(&vt596_adapter.dev, "    ");
		for (; i < I2C_SMBUS_BLOCK_MAX - 1; i++)
			printk("%02x,", inb_p(SMBBLKDAT));
		printk("%02x\n", inb_p(SMBBLKDAT));
	}
}
#else
static inline void vt596_dump_regs(const char *msg, u8 size) { }
#endif

/* Return -1 on error, 0 on success */
static int vt596_transaction(u8 size)
{
	int temp;
	int result = 0;
	int timeout = 0;

	vt596_dump_regs("Transaction (pre)", size);

	/* Make sure the SMBus host is ready to start transmitting */
	if ((temp = inb_p(SMBHSTSTS)) & 0x1F) {
		dev_dbg(&vt596_adapter.dev, "SMBus busy (0x%02x). "
			"Resetting...\n", temp);

		outb_p(temp, SMBHSTSTS);
		if ((temp = inb_p(SMBHSTSTS)) & 0x1F) {
			dev_err(&vt596_adapter.dev, "SMBus reset failed! "
				"(0x%02x)\n", temp);
			return -EBUSY;
		}
	}

	/* Start the transaction by setting bit 6 */
	outb_p(0x40 | size, SMBHSTCNT);

	/* We will always wait for a fraction of a second */
	do {
		msleep(1);
		temp = inb_p(SMBHSTSTS);
	} while ((temp & 0x01) && (++timeout < MAX_TIMEOUT));

	/* If the SMBus is still busy, we give up */
	if (timeout == MAX_TIMEOUT) {
		result = -ETIMEDOUT;
		dev_err(&vt596_adapter.dev, "SMBus timeout!\n");
	}

	if (temp & 0x10) {
		result = -EIO;
		dev_err(&vt596_adapter.dev, "Transaction failed (0x%02x)\n",
			size);
	}

	if (temp & 0x08) {
		result = -EIO;
		dev_err(&vt596_adapter.dev, "SMBus collision!\n");
	}

	if (temp & 0x04) {
		result = -ENXIO;
		dev_dbg(&vt596_adapter.dev, "No response\n");
	}

	/* Resetting status register */
	if (temp & 0x1F)
		outb_p(temp, SMBHSTSTS);

	vt596_dump_regs("Transaction (post)", size);

Annotation

Implementation Notes