static int atmel_spi_probe()

in spi-atmel.c [1437:1597]

• 130 lines of code
• 22 McCabe index (conditional complexity)

static int atmel_spi_probe(struct platform_device *pdev)
{
	struct resource		*regs;
	int			irq;
	struct clk		*clk;
	int			ret;
	struct spi_master	*master;
	struct atmel_spi	*as;

	/* Select default pin state */
	pinctrl_pm_select_default_state(&pdev->dev);

	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!regs)
		return -ENXIO;

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return irq;

	clk = devm_clk_get(&pdev->dev, "spi_clk");
	if (IS_ERR(clk))
		return PTR_ERR(clk);

	/* setup spi core then atmel-specific driver state */
	master = spi_alloc_master(&pdev->dev, sizeof(*as));
	if (!master)
		return -ENOMEM;

	/* the spi->mode bits understood by this driver: */
	master->use_gpio_descriptors = true;
	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 16);
	master->dev.of_node = pdev->dev.of_node;
	master->bus_num = pdev->id;
	master->num_chipselect = 4;
	master->setup = atmel_spi_setup;
	master->flags = (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX |
			SPI_MASTER_GPIO_SS);
	master->transfer_one = atmel_spi_one_transfer;
	master->set_cs = atmel_spi_set_cs;
	master->cleanup = atmel_spi_cleanup;
	master->auto_runtime_pm = true;
	master->max_dma_len = SPI_MAX_DMA_XFER;
	master->can_dma = atmel_spi_can_dma;
	platform_set_drvdata(pdev, master);

	as = spi_master_get_devdata(master);

	spin_lock_init(&as->lock);

	as->pdev = pdev;
	as->regs = devm_ioremap_resource(&pdev->dev, regs);
	if (IS_ERR(as->regs)) {
		ret = PTR_ERR(as->regs);
		goto out_unmap_regs;
	}
	as->phybase = regs->start;
	as->irq = irq;
	as->clk = clk;

	init_completion(&as->xfer_completion);

	atmel_get_caps(as);

	as->use_dma = false;
	as->use_pdc = false;
	if (as->caps.has_dma_support) {
		ret = atmel_spi_configure_dma(master, as);
		if (ret == 0) {
			as->use_dma = true;
		} else if (ret == -EPROBE_DEFER) {
			goto out_unmap_regs;
		}
	} else if (as->caps.has_pdc_support) {
		as->use_pdc = true;
	}

	if (IS_ENABLED(CONFIG_SOC_SAM_V4_V5)) {
		as->addr_rx_bbuf = dma_alloc_coherent(&pdev->dev,
						      SPI_MAX_DMA_XFER,
						      &as->dma_addr_rx_bbuf,
						      GFP_KERNEL | GFP_DMA);
		if (!as->addr_rx_bbuf) {
			as->use_dma = false;
		} else {
			as->addr_tx_bbuf = dma_alloc_coherent(&pdev->dev,
					SPI_MAX_DMA_XFER,
					&as->dma_addr_tx_bbuf,
					GFP_KERNEL | GFP_DMA);
			if (!as->addr_tx_bbuf) {
				as->use_dma = false;
				dma_free_coherent(&pdev->dev, SPI_MAX_DMA_XFER,
						  as->addr_rx_bbuf,
						  as->dma_addr_rx_bbuf);
			}
		}
		if (!as->use_dma)
			dev_info(master->dev.parent,
				 "  can not allocate dma coherent memory\n");
	}

	if (as->caps.has_dma_support && !as->use_dma)
		dev_info(&pdev->dev, "Atmel SPI Controller using PIO only\n");

	if (as->use_pdc) {
		ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pdc_interrupt,
					0, dev_name(&pdev->dev), master);
	} else {
		ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pio_interrupt,
					0, dev_name(&pdev->dev), master);
	}
	if (ret)
		goto out_unmap_regs;

	/* Initialize the hardware */
	ret = clk_prepare_enable(clk);
	if (ret)
		goto out_free_irq;

	as->spi_clk = clk_get_rate(clk);

	as->fifo_size = 0;
	if (!of_property_read_u32(pdev->dev.of_node, "atmel,fifo-size",
				  &as->fifo_size)) {
		dev_info(&pdev->dev, "Using FIFO (%u data)\n", as->fifo_size);
	}

	atmel_spi_init(as);

	pm_runtime_set_autosuspend_delay(&pdev->dev, AUTOSUSPEND_TIMEOUT);
	pm_runtime_use_autosuspend(&pdev->dev);
	pm_runtime_set_active(&pdev->dev);
	pm_runtime_enable(&pdev->dev);

	ret = devm_spi_register_master(&pdev->dev, master);
	if (ret)
		goto out_free_dma;

	/* go! */
	dev_info(&pdev->dev, "Atmel SPI Controller version 0x%x at 0x%08lx (irq %d)\n",
			atmel_get_version(as), (unsigned long)regs->start,
			irq);

	return 0;

out_free_dma:
	pm_runtime_disable(&pdev->dev);
	pm_runtime_set_suspended(&pdev->dev);

	if (as->use_dma)
		atmel_spi_release_dma(master);

	spi_writel(as, CR, SPI_BIT(SWRST));
	spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
	clk_disable_unprepare(clk);
out_free_irq:
out_unmap_regs:
	spi_master_put(master);
	return ret;
}