static int spi_ppc4xx_of_probe()

in spi-ppc4xx.c [340:465]

• 98 lines of code
• 10 McCabe index (conditional complexity)

static int spi_ppc4xx_of_probe(struct platform_device *op)
{
	struct ppc4xx_spi *hw;
	struct spi_master *master;
	struct spi_bitbang *bbp;
	struct resource resource;
	struct device_node *np = op->dev.of_node;
	struct device *dev = &op->dev;
	struct device_node *opbnp;
	int ret;
	const unsigned int *clk;

	master = spi_alloc_master(dev, sizeof(*hw));
	if (master == NULL)
		return -ENOMEM;
	master->dev.of_node = np;
	platform_set_drvdata(op, master);
	hw = spi_master_get_devdata(master);
	hw->master = master;
	hw->dev = dev;

	init_completion(&hw->done);

	/* Setup the state for the bitbang driver */
	bbp = &hw->bitbang;
	bbp->master = hw->master;
	bbp->setup_transfer = spi_ppc4xx_setupxfer;
	bbp->txrx_bufs = spi_ppc4xx_txrx;
	bbp->use_dma = 0;
	bbp->master->setup = spi_ppc4xx_setup;
	bbp->master->cleanup = spi_ppc4xx_cleanup;
	bbp->master->bits_per_word_mask = SPI_BPW_MASK(8);
	bbp->master->use_gpio_descriptors = true;
	/*
	 * The SPI core will count the number of GPIO descriptors to figure
	 * out the number of chip selects available on the platform.
	 */
	bbp->master->num_chipselect = 0;

	/* the spi->mode bits understood by this driver: */
	bbp->master->mode_bits =
		SPI_CPHA | SPI_CPOL | SPI_CS_HIGH | SPI_LSB_FIRST;

	/* Get the clock for the OPB */
	opbnp = of_find_compatible_node(NULL, NULL, "ibm,opb");
	if (opbnp == NULL) {
		dev_err(dev, "OPB: cannot find node\n");
		ret = -ENODEV;
		goto free_master;
	}
	/* Get the clock (Hz) for the OPB */
	clk = of_get_property(opbnp, "clock-frequency", NULL);
	if (clk == NULL) {
		dev_err(dev, "OPB: no clock-frequency property set\n");
		of_node_put(opbnp);
		ret = -ENODEV;
		goto free_master;
	}
	hw->opb_freq = *clk;
	hw->opb_freq >>= 2;
	of_node_put(opbnp);

	ret = of_address_to_resource(np, 0, &resource);
	if (ret) {
		dev_err(dev, "error while parsing device node resource\n");
		goto free_master;
	}
	hw->mapbase = resource.start;
	hw->mapsize = resource_size(&resource);

	/* Sanity check */
	if (hw->mapsize < sizeof(struct spi_ppc4xx_regs)) {
		dev_err(dev, "too small to map registers\n");
		ret = -EINVAL;
		goto free_master;
	}

	/* Request IRQ */
	hw->irqnum = irq_of_parse_and_map(np, 0);
	ret = request_irq(hw->irqnum, spi_ppc4xx_int,
			  0, "spi_ppc4xx_of", (void *)hw);
	if (ret) {
		dev_err(dev, "unable to allocate interrupt\n");
		goto free_master;
	}

	if (!request_mem_region(hw->mapbase, hw->mapsize, DRIVER_NAME)) {
		dev_err(dev, "resource unavailable\n");
		ret = -EBUSY;
		goto request_mem_error;
	}

	hw->regs = ioremap(hw->mapbase, sizeof(struct spi_ppc4xx_regs));

	if (!hw->regs) {
		dev_err(dev, "unable to memory map registers\n");
		ret = -ENXIO;
		goto map_io_error;
	}

	spi_ppc4xx_enable(hw);

	/* Finally register our spi controller */
	dev->dma_mask = 0;
	ret = spi_bitbang_start(bbp);
	if (ret) {
		dev_err(dev, "failed to register SPI master\n");
		goto unmap_regs;
	}

	dev_info(dev, "driver initialized\n");

	return 0;

unmap_regs:
	iounmap(hw->regs);
map_io_error:
	release_mem_region(hw->mapbase, hw->mapsize);
request_mem_error:
	free_irq(hw->irqnum, hw);
free_master:
	spi_master_put(master);

	dev_err(dev, "initialization failed\n");
	return ret;
}