static int stm32_spi_probe()

in spi-stm32.c [1757:1921]

• 139 lines of code
• 21 McCabe index (conditional complexity)

static int stm32_spi_probe(struct platform_device *pdev)
{
	struct spi_master *master;
	struct stm32_spi *spi;
	struct resource *res;
	struct reset_control *rst;
	int ret;

	master = devm_spi_alloc_master(&pdev->dev, sizeof(struct stm32_spi));
	if (!master) {
		dev_err(&pdev->dev, "spi master allocation failed\n");
		return -ENOMEM;
	}
	platform_set_drvdata(pdev, master);

	spi = spi_master_get_devdata(master);
	spi->dev = &pdev->dev;
	spi->master = master;
	spin_lock_init(&spi->lock);

	spi->cfg = (const struct stm32_spi_cfg *)
		of_match_device(pdev->dev.driver->of_match_table,
				&pdev->dev)->data;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	spi->base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(spi->base))
		return PTR_ERR(spi->base);

	spi->phys_addr = (dma_addr_t)res->start;

	spi->irq = platform_get_irq(pdev, 0);
	if (spi->irq <= 0)
		return dev_err_probe(&pdev->dev, spi->irq,
				     "failed to get irq\n");

	ret = devm_request_threaded_irq(&pdev->dev, spi->irq,
					spi->cfg->irq_handler_event,
					spi->cfg->irq_handler_thread,
					IRQF_ONESHOT, pdev->name, master);
	if (ret) {
		dev_err(&pdev->dev, "irq%d request failed: %d\n", spi->irq,
			ret);
		return ret;
	}

	spi->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(spi->clk)) {
		ret = PTR_ERR(spi->clk);
		dev_err(&pdev->dev, "clk get failed: %d\n", ret);
		return ret;
	}

	ret = clk_prepare_enable(spi->clk);
	if (ret) {
		dev_err(&pdev->dev, "clk enable failed: %d\n", ret);
		return ret;
	}
	spi->clk_rate = clk_get_rate(spi->clk);
	if (!spi->clk_rate) {
		dev_err(&pdev->dev, "clk rate = 0\n");
		ret = -EINVAL;
		goto err_clk_disable;
	}

	rst = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);
	if (rst) {
		if (IS_ERR(rst)) {
			ret = dev_err_probe(&pdev->dev, PTR_ERR(rst),
					    "failed to get reset\n");
			goto err_clk_disable;
		}

		reset_control_assert(rst);
		udelay(2);
		reset_control_deassert(rst);
	}

	if (spi->cfg->has_fifo)
		spi->fifo_size = spi->cfg->get_fifo_size(spi);

	ret = spi->cfg->config(spi);
	if (ret) {
		dev_err(&pdev->dev, "controller configuration failed: %d\n",
			ret);
		goto err_clk_disable;
	}

	master->dev.of_node = pdev->dev.of_node;
	master->auto_runtime_pm = true;
	master->bus_num = pdev->id;
	master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_CS_HIGH | SPI_LSB_FIRST |
			    SPI_3WIRE;
	master->bits_per_word_mask = spi->cfg->get_bpw_mask(spi);
	master->max_speed_hz = spi->clk_rate / spi->cfg->baud_rate_div_min;
	master->min_speed_hz = spi->clk_rate / spi->cfg->baud_rate_div_max;
	master->use_gpio_descriptors = true;
	master->prepare_message = stm32_spi_prepare_msg;
	master->transfer_one = stm32_spi_transfer_one;
	master->unprepare_message = stm32_spi_unprepare_msg;
	master->flags = SPI_MASTER_MUST_TX;

	spi->dma_tx = dma_request_chan(spi->dev, "tx");
	if (IS_ERR(spi->dma_tx)) {
		ret = PTR_ERR(spi->dma_tx);
		spi->dma_tx = NULL;
		if (ret == -EPROBE_DEFER)
			goto err_clk_disable;

		dev_warn(&pdev->dev, "failed to request tx dma channel\n");
	} else {
		master->dma_tx = spi->dma_tx;
	}

	spi->dma_rx = dma_request_chan(spi->dev, "rx");
	if (IS_ERR(spi->dma_rx)) {
		ret = PTR_ERR(spi->dma_rx);
		spi->dma_rx = NULL;
		if (ret == -EPROBE_DEFER)
			goto err_dma_release;

		dev_warn(&pdev->dev, "failed to request rx dma channel\n");
	} else {
		master->dma_rx = spi->dma_rx;
	}

	if (spi->dma_tx || spi->dma_rx)
		master->can_dma = stm32_spi_can_dma;

	pm_runtime_set_autosuspend_delay(&pdev->dev,
					 STM32_SPI_AUTOSUSPEND_DELAY);
	pm_runtime_use_autosuspend(&pdev->dev);
	pm_runtime_set_active(&pdev->dev);
	pm_runtime_get_noresume(&pdev->dev);
	pm_runtime_enable(&pdev->dev);

	ret = spi_register_master(master);
	if (ret) {
		dev_err(&pdev->dev, "spi master registration failed: %d\n",
			ret);
		goto err_pm_disable;
	}

	pm_runtime_mark_last_busy(&pdev->dev);
	pm_runtime_put_autosuspend(&pdev->dev);

	dev_info(&pdev->dev, "driver initialized\n");

	return 0;

err_pm_disable:
	pm_runtime_disable(&pdev->dev);
	pm_runtime_put_noidle(&pdev->dev);
	pm_runtime_set_suspended(&pdev->dev);
	pm_runtime_dont_use_autosuspend(&pdev->dev);
err_dma_release:
	if (spi->dma_tx)
		dma_release_channel(spi->dma_tx);
	if (spi->dma_rx)
		dma_release_channel(spi->dma_rx);
err_clk_disable:
	clk_disable_unprepare(spi->clk);

	return ret;
}