static int mpc52xx_spi_probe()

in spi-mpc52xx.c [381:516]

• 109 lines of code
• 15 McCabe index (conditional complexity)

static int mpc52xx_spi_probe(struct platform_device *op)
{
	struct spi_master *master;
	struct mpc52xx_spi *ms;
	void __iomem *regs;
	u8 ctrl1;
	int rc, i = 0;
	int gpio_cs;

	/* MMIO registers */
	dev_dbg(&op->dev, "probing mpc5200 SPI device\n");
	regs = of_iomap(op->dev.of_node, 0);
	if (!regs)
		return -ENODEV;

	/* initialize the device */
	ctrl1 = SPI_CTRL1_SPIE | SPI_CTRL1_SPE | SPI_CTRL1_MSTR;
	out_8(regs + SPI_CTRL1, ctrl1);
	out_8(regs + SPI_CTRL2, 0x0);
	out_8(regs + SPI_DATADIR, 0xe);	/* Set output pins */
	out_8(regs + SPI_PORTDATA, 0x8);	/* Deassert /SS signal */

	/* Clear the status register and re-read it to check for a MODF
	 * failure.  This driver cannot currently handle multiple masters
	 * on the SPI bus.  This fault will also occur if the SPI signals
	 * are not connected to any pins (port_config setting) */
	in_8(regs + SPI_STATUS);
	out_8(regs + SPI_CTRL1, ctrl1);

	in_8(regs + SPI_DATA);
	if (in_8(regs + SPI_STATUS) & SPI_STATUS_MODF) {
		dev_err(&op->dev, "mode fault; is port_config correct?\n");
		rc = -EIO;
		goto err_init;
	}

	dev_dbg(&op->dev, "allocating spi_master struct\n");
	master = spi_alloc_master(&op->dev, sizeof(*ms));
	if (!master) {
		rc = -ENOMEM;
		goto err_alloc;
	}

	master->transfer = mpc52xx_spi_transfer;
	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST;
	master->bits_per_word_mask = SPI_BPW_MASK(8);
	master->dev.of_node = op->dev.of_node;

	platform_set_drvdata(op, master);

	ms = spi_master_get_devdata(master);
	ms->master = master;
	ms->regs = regs;
	ms->irq0 = irq_of_parse_and_map(op->dev.of_node, 0);
	ms->irq1 = irq_of_parse_and_map(op->dev.of_node, 1);
	ms->state = mpc52xx_spi_fsmstate_idle;
	ms->ipb_freq = mpc5xxx_get_bus_frequency(op->dev.of_node);
	ms->gpio_cs_count = of_gpio_count(op->dev.of_node);
	if (ms->gpio_cs_count > 0) {
		master->num_chipselect = ms->gpio_cs_count;
		ms->gpio_cs = kmalloc_array(ms->gpio_cs_count,
					    sizeof(*ms->gpio_cs),
					    GFP_KERNEL);
		if (!ms->gpio_cs) {
			rc = -ENOMEM;
			goto err_alloc_gpio;
		}

		for (i = 0; i < ms->gpio_cs_count; i++) {
			gpio_cs = of_get_gpio(op->dev.of_node, i);
			if (!gpio_is_valid(gpio_cs)) {
				dev_err(&op->dev,
					"could not parse the gpio field in oftree\n");
				rc = -ENODEV;
				goto err_gpio;
			}

			rc = gpio_request(gpio_cs, dev_name(&op->dev));
			if (rc) {
				dev_err(&op->dev,
					"can't request spi cs gpio #%d on gpio line %d\n",
					i, gpio_cs);
				goto err_gpio;
			}

			gpio_direction_output(gpio_cs, 1);
			ms->gpio_cs[i] = gpio_cs;
		}
	}

	spin_lock_init(&ms->lock);
	INIT_LIST_HEAD(&ms->queue);
	INIT_WORK(&ms->work, mpc52xx_spi_wq);

	/* Decide if interrupts can be used */
	if (ms->irq0 && ms->irq1) {
		rc = request_irq(ms->irq0, mpc52xx_spi_irq, 0,
				  "mpc5200-spi-modf", ms);
		rc |= request_irq(ms->irq1, mpc52xx_spi_irq, 0,
				  "mpc5200-spi-spif", ms);
		if (rc) {
			free_irq(ms->irq0, ms);
			free_irq(ms->irq1, ms);
			ms->irq0 = ms->irq1 = 0;
		}
	} else {
		/* operate in polled mode */
		ms->irq0 = ms->irq1 = 0;
	}

	if (!ms->irq0)
		dev_info(&op->dev, "using polled mode\n");

	dev_dbg(&op->dev, "registering spi_master struct\n");
	rc = spi_register_master(master);
	if (rc)
		goto err_register;

	dev_info(&ms->master->dev, "registered MPC5200 SPI bus\n");

	return rc;

 err_register:
	dev_err(&ms->master->dev, "initialization failed\n");
 err_gpio:
	while (i-- > 0)
		gpio_free(ms->gpio_cs[i]);

	kfree(ms->gpio_cs);
 err_alloc_gpio:
	spi_master_put(master);
 err_alloc:
 err_init:
	iounmap(regs);
	return rc;
}