spi_imx.c

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	/* SPI chip-select management */
	if (chip_info->cs_control)
		chip->cs_control = chip_info->cs_control;
	else
		chip->cs_control = null_cs_control;

	/* Save controller_state */
	spi_set_ctldata(spi, chip);

	/* Summary */
	dev_dbg(&spi->dev,
		"setup succeded\n"
		"    loopback enable   = %s\n"
		"    dma enable        = %s\n"
		"    insert /ss pulse  = %s\n"
		"    period wait       = %d\n"
		"    mode              = %d\n"
		"    bits per word     = %d\n"
		"    min speed         = %d Hz\n"
		"    rounded max speed = %d Hz\n",
		chip->test & SPI_TEST_LBC ? "Yes" : "No",
		chip->enable_dma ? "Yes" : "No",
		chip->control & SPI_CONTROL_SSCTL ? "Yes" : "No",
		chip->period & SPI_PERIOD_WAIT,
		spi->mode,
		spi->bits_per_word,
		spi_speed_hz(SPI_CONTROL_DATARATE_MIN),
		spi->max_speed_hz);
	return status;

err_first_setup:
	kfree(chip);
	return status;
}

static void cleanup(struct spi_device *spi)
{
	kfree(spi_get_ctldata(spi));
}

static int __init init_queue(struct driver_data *drv_data)
{
	INIT_LIST_HEAD(&drv_data->queue);
	spin_lock_init(&drv_data->lock);

	drv_data->run = QUEUE_STOPPED;
	drv_data->busy = 0;

	tasklet_init(&drv_data->pump_transfers,
			pump_transfers,	(unsigned long)drv_data);

	INIT_WORK(&drv_data->work, pump_messages);
	drv_data->workqueue = create_singlethread_workqueue(
					drv_data->master->dev.parent->bus_id);
	if (drv_data->workqueue == NULL)
		return -EBUSY;

	return 0;
}

static int start_queue(struct driver_data *drv_data)
{
	unsigned long flags;

	spin_lock_irqsave(&drv_data->lock, flags);

	if (drv_data->run == QUEUE_RUNNING || drv_data->busy) {
		spin_unlock_irqrestore(&drv_data->lock, flags);
		return -EBUSY;
	}

	drv_data->run = QUEUE_RUNNING;
	drv_data->cur_msg = NULL;
	drv_data->cur_transfer = NULL;
	drv_data->cur_chip = NULL;
	spin_unlock_irqrestore(&drv_data->lock, flags);

	queue_work(drv_data->workqueue, &drv_data->work);

	return 0;
}

static int stop_queue(struct driver_data *drv_data)
{
	unsigned long flags;
	unsigned limit = 500;
	int status = 0;

	spin_lock_irqsave(&drv_data->lock, flags);

	/* This is a bit lame, but is optimized for the common execution path.
	 * A wait_queue on the drv_data->busy could be used, but then the common
	 * execution path (pump_messages) would be required to call wake_up or
	 * friends on every SPI message. Do this instead */
	drv_data->run = QUEUE_STOPPED;
	while (!list_empty(&drv_data->queue) && drv_data->busy && limit--) {
		spin_unlock_irqrestore(&drv_data->lock, flags);
		msleep(10);
		spin_lock_irqsave(&drv_data->lock, flags);
	}

	if (!list_empty(&drv_data->queue) || drv_data->busy)
		status = -EBUSY;

	spin_unlock_irqrestore(&drv_data->lock, flags);

	return status;
}

static int destroy_queue(struct driver_data *drv_data)
{
	int status;

	status = stop_queue(drv_data);
	if (status != 0)
		return status;

	if (drv_data->workqueue)
		destroy_workqueue(drv_data->workqueue);

	return 0;
}

static int __init spi_imx_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct spi_imx_master *platform_info;
	struct spi_master *master;
	struct driver_data *drv_data = NULL;
	struct resource *res;
	int irq, status = 0;

	platform_info = dev->platform_data;
	if (platform_info == NULL) {
		dev_err(&pdev->dev, "probe - no platform data supplied\n");
		status = -ENODEV;
		goto err_no_pdata;
	}

	/* Allocate master with space for drv_data */
	master = spi_alloc_master(dev, sizeof(struct driver_data));
	if (!master) {
		dev_err(&pdev->dev, "probe - cannot alloc spi_master\n");
		status = -ENOMEM;
		goto err_no_mem;
	}
	drv_data = spi_master_get_devdata(master);
	drv_data->master = master;
	drv_data->master_info = platform_info;
	drv_data->pdev = pdev;

	master->bus_num = pdev->id;
	master->num_chipselect = platform_info->num_chipselect;
	master->cleanup = cleanup;
	master->setup = setup;
	master->transfer = transfer;

	drv_data->dummy_dma_buf = SPI_DUMMY_u32;

	/* Find and map resources */
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		dev_err(&pdev->dev, "probe - MEM resources not defined\n");
		status = -ENODEV;
		goto err_no_iores;
	}
	drv_data->ioarea = request_mem_region(res->start,
						res->end - res->start + 1,
						pdev->name);
	if (drv_data->ioarea == NULL) {
		dev_err(&pdev->dev, "probe - cannot reserve region\n");
		status = -ENXIO;
		goto err_no_iores;
	}
	drv_data->regs = ioremap(res->start, res->end - res->start + 1);
	if (drv_data->regs == NULL) {
		dev_err(&pdev->dev, "probe - cannot map IO\n");
		status = -ENXIO;
		goto err_no_iomap;
	}
	drv_data->rd_data_phys = (dma_addr_t)res->start;

	/* Attach to IRQ */
	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		dev_err(&pdev->dev, "probe - IRQ resource not defined\n");
		status = -ENODEV;
		goto err_no_irqres;
	}
	status = request_irq(irq, spi_int, IRQF_DISABLED, dev->bus_id, drv_data);
	if (status < 0) {
		dev_err(&pdev->dev, "probe - cannot get IRQ (%d)\n", status);
		goto err_no_irqres;
	}

	/* Setup DMA if requested */
	drv_data->tx_channel = -1;
	drv_data->rx_channel = -1;
	if (platform_info->enable_dma) {
		/* Get rx DMA channel */
		status = imx_dma_request_by_prio(&drv_data->rx_channel,
			"spi_imx_rx", DMA_PRIO_HIGH);
		if (status < 0) {
			dev_err(dev,
				"probe - problem (%d) requesting rx channel\n",
				status);
			goto err_no_rxdma;
		} else
			imx_dma_setup_handlers(drv_data->rx_channel, NULL,
						dma_err_handler, drv_data);

		/* Get tx DMA channel */
		status = imx_dma_request_by_prio(&drv_data->tx_channel,
						"spi_imx_tx", DMA_PRIO_MEDIUM);
		if (status < 0) {
			dev_err(dev,
				"probe - problem (%d) requesting tx channel\n",
				status);
			imx_dma_free(drv_data->rx_channel);
			goto err_no_txdma;
		} else
			imx_dma_setup_handlers(drv_data->tx_channel,
						dma_tx_handler, dma_err_handler,
						drv_data);

		/* Set request source and burst length for allocated channels */
		switch (drv_data->pdev->id) {
		case 1:
			/* Using SPI1 */
			RSSR(drv_data->rx_channel) = DMA_REQ_SPI1_R;
			RSSR(drv_data->tx_channel) = DMA_REQ_SPI1_T;
			break;
		case 2:
			/* Using SPI2 */
			RSSR(drv_data->rx_channel) = DMA_REQ_SPI2_R;
			RSSR(drv_data->tx_channel) = DMA_REQ_SPI2_T;
			break;
		default:
			dev_err(dev, "probe - bad SPI Id\n");
			imx_dma_free(drv_data->rx_channel);
			imx_dma_free(drv_data->tx_channel);
			status = -ENODEV;
			goto err_no_devid;
		}
		BLR(drv_data->rx_channel) = SPI_DMA_BLR;
		BLR(drv_data->tx_channel) = SPI_DMA_BLR;
	}

	/* Load default SPI configuration */
	writel(SPI_RESET_START, drv_data->regs + SPI_RESET);
	writel(0, drv_data->regs + SPI_RESET);
	writel(SPI_DEFAULT_CONTROL, drv_data->regs + SPI_CONTROL);

	/* Initial and start queue */
	status = init_queue(drv_data);
	if (status != 0) {
		dev_err(&pdev->dev, "probe - problem initializing queue\n");
		goto err_init_queue;
	}
	status = start_queue(drv_data);
	if (status != 0) {
		dev_err(&pdev->dev, "probe - problem starting queue\n");
		goto err_start_queue;
	}

	/* Register with the SPI framework */
	platform_set_drvdata(pdev, drv_data);
	status = spi_register_master(master);
	if (status != 0) {
		dev_err(&pdev->dev, "probe - problem registering spi master\n");
		goto err_spi_register;
	}

	dev_dbg(dev, "probe succeded\n");
	return 0;

err_init_queue:
err_start_queue:
err_spi_register:
	destroy_queue(drv_data);

err_no_rxdma:
err_no_txdma:
err_no_devid:
	free_irq(irq, drv_data);

err_no_irqres:
	iounmap(drv_data->regs);

err_no_iomap:
	release_resource(drv_data->ioarea);
	kfree(drv_data->ioarea);

err_no_iores:
	spi_master_put(master);

err_no_pdata:
err_no_mem:
	return status;
}

static int __exit spi_imx_remove(struct platform_device *pdev)
{
	struct driver_data *drv_data = platform_get_drvdata(pdev);
	int irq;
	int status = 0;

	if (!drv_data)
		return 0;

	tasklet_kill(&drv_data->pump_transfers);

	/* Remove the queue */
	status = destroy_queue(drv_data);
	if (status != 0) {
		dev_err(&pdev->dev, "queue remove failed (%d)\n", status);
		return status;
	}

	/* Reset SPI */
	writel(SPI_RESET_START, drv_data->regs + SPI_RESET);
	writel(0, drv_data->regs + SPI_RESET);

	/* Release DMA */
	if (drv_data->master_info->enable_dma) {
		RSSR(drv_data->rx_channel) = 0;
		RSSR(drv_data->tx_channel) = 0;
		imx_dma_free(drv_data->tx_channel);
		imx_dma_free(drv_data->rx_channel);
	}

	/* Release IRQ */
	irq = platform_get_irq(pdev, 0);
	if (irq >= 0)
		free_irq(irq, drv_data);

	/* Release map resources */
	iounmap(drv_data->regs);
	release_resource(drv_data->ioarea);
	kfree(drv_data->ioarea);

	/* Disconnect from the SPI framework */
	spi_unregister_master(drv_data->master);
	spi_master_put(drv_data->master);

	/* Prevent double remove */
	platform_set_drvdata(pdev, NULL);

	dev_dbg(&pdev->dev, "remove succeded\n");

	return 0;
}

static void spi_imx_shutdown(struct platform_device *pdev)
{
	struct driver_data *drv_data = platform_get_drvdata(pdev);

	/* Reset SPI */
	writel(SPI_RESET_START, drv_data->regs + SPI_RESET);
	writel(0, drv_data->regs + SPI_RESET);

	dev_dbg(&pdev->dev, "shutdown succeded\n");
}

#ifdef CONFIG_PM
static int suspend_devices(struct device *dev, void *pm_message)
{
	pm_message_t *state = pm_message;

	if (dev->power.power_state.event != state->event) {
		dev_warn(dev, "pm state does not match request\n");
		return -1;
	}

	return 0;
}

static int spi_imx_suspend(struct platform_device *pdev, pm_message_t state)
{
	struct driver_data *drv_data = platform_get_drvdata(pdev);
	int status = 0;

	status = stop_queue(drv_data);
	if (status != 0) {
		dev_warn(&pdev->dev, "suspend cannot stop queue\n");
		return status;
	}

	dev_dbg(&pdev->dev, "suspended\n");

	return 0;
}

static int spi_imx_resume(struct platform_device *pdev)
{
	struct driver_data *drv_data = platform_get_drvdata(pdev);
	int status = 0;

	/* Start the queue running */
	status = start_queue(drv_data);
	if (status != 0)
		dev_err(&pdev->dev, "problem starting queue (%d)\n", status);
	else
		dev_dbg(&pdev->dev, "resumed\n");

	return status;
}
#else
#define spi_imx_suspend NULL
#define spi_imx_resume NULL
#endif /* CONFIG_PM */

static struct platform_driver driver = {
	.driver = {
		.name = "spi_imx",
		.bus = &platform_bus_type,
		.owner = THIS_MODULE,
	},
	.remove = __exit_p(spi_imx_remove),
	.shutdown = spi_imx_shutdown,
	.suspend = spi_imx_suspend,
	.resume = spi_imx_resume,
};

static int __init spi_imx_init(void)
{
	return platform_driver_probe(&driver, spi_imx_probe);
}
module_init(spi_imx_init);

static void __exit spi_imx_exit(void)
{
	platform_driver_unregister(&driver);
}
module_exit(spi_imx_exit);

MODULE_AUTHOR("Andrea Paterniani, <[e-mail]>");
MODULE_DESCRIPTION("iMX SPI Controller Driver");
MODULE_LICENSE("GPL");