drivers/net/can/sja1000/tscan1.c

Source file repositories/reference/linux-study-clean/drivers/net/can/sja1000/tscan1.c

File Facts

System
Linux kernel
Corpus path
drivers/net/can/sja1000/tscan1.c
Extension
.c
Size
4962 bytes
Lines
192
Domain
Driver Families
Bucket
drivers/net
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

inb(pld_base + TSCAN1_ID2) != TSCAN1_ID2_VALUE) {
		release_region(pld_base, TSCAN1_PLD_SIZE);
		return -ENODEV;
	}

	switch (inb(pld_base + TSCAN1_JUMPERS) & (TSCAN1_JP4 | TSCAN1_JP5)) {
	case TSCAN1_JP4:
		irq = 6;
		break;
	case TSCAN1_JP5:
		irq = 7;
		break;
	case TSCAN1_JP4 | TSCAN1_JP5:
		irq = 5;
		break;
	default:
		dev_err(dev, "invalid JP4:JP5 setting (no IRQ)\n");
		release_region(pld_base, TSCAN1_PLD_SIZE);
		return -EINVAL;
	}

	netdev = alloc_sja1000dev(0);
	if (!netdev) {
		release_region(pld_base, TSCAN1_PLD_SIZE);
		return -ENOMEM;
	}

	dev_set_drvdata(dev, netdev);
	SET_NETDEV_DEV(netdev, dev);

	netdev->base_addr = pld_base;
	netdev->irq = irq;

	priv = netdev_priv(netdev);
	priv->read_reg = tscan1_read;
	priv->write_reg = tscan1_write;
	priv->can.clock.freq = TSCAN1_SJA1000_XTAL / 2;
	priv->cdr = CDR_CBP | CDR_CLK_OFF;
	priv->ocr = OCR_TX0_PUSHPULL;

	/* Select the first SJA1000 IO address that is free and that works */
	for (i = 0; i < ARRAY_SIZE(tscan1_sja1000_addresses); i++) {
		sja1000_base = tscan1_sja1000_addresses[i];
		if (!request_region(sja1000_base, TSCAN1_SJA1000_SIZE,
								dev_name(dev)))
			continue;

		/* Set SJA1000 IO base address and enable it */
		outb(TSCAN1_MODE_ENABLE | i, pld_base + TSCAN1_MODE);

		priv->reg_base = (void __iomem *)sja1000_base;
		if (!register_sja1000dev(netdev)) {
			/* SJA1000 probe succeeded; turn LED off and return */
			outb(0, pld_base + TSCAN1_LED);
			netdev_info(netdev, "TS-CAN1 at 0x%lx 0x%lx irq %d\n",
						pld_base, sja1000_base, irq);
			return 0;
		}

		/* SJA1000 probe failed; release and try next address */
		outb(0, pld_base + TSCAN1_MODE);
		release_region(sja1000_base, TSCAN1_SJA1000_SIZE);
	}

	dev_err(dev, "failed to assign SJA1000 IO address\n");
	dev_set_drvdata(dev, NULL);
	free_sja1000dev(netdev);
	release_region(pld_base, TSCAN1_PLD_SIZE);
	return -ENXIO;
}

static void tscan1_remove(struct device *dev, unsigned id /*unused*/)
{
	struct net_device *netdev;
	struct sja1000_priv *priv;
	unsigned long pld_base, sja1000_base;

	netdev = dev_get_drvdata(dev);
	unregister_sja1000dev(netdev);
	dev_set_drvdata(dev, NULL);

	priv = netdev_priv(netdev);
	pld_base = netdev->base_addr;
	sja1000_base = (unsigned long)priv->reg_base;

	outb(0, pld_base + TSCAN1_MODE);	/* disable SJA1000 IO space */

	release_region(sja1000_base, TSCAN1_SJA1000_SIZE);
	release_region(pld_base, TSCAN1_PLD_SIZE);

Annotation

Implementation Notes