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Date: Mon, 17 Jan 2011 02:27:56 -0500
From: Sinan Akman <sinan@...teme.com>
To: Thomas Chou <thomas@...ron.com.tw>
CC: David Brownell <dbrownell@...rs.sourceforge.net>,
Grant Likely <grant.likely@...retlab.ca>,
nios2-dev@...c.et.ntust.edu.tw, Mike Frysinger <vapier@...too.org>,
devicetree-discuss@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
spi-devel-general@...ts.sourceforge.net
Subject: Re: [PATCH v3] spi: New driver for Altera SPI
Thomas Chou wrote:
[...]
> +
> +static int altera_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
> +{
> + struct altera_spi *hw = to_hw(spi);
> +
> + hw->tx = t->tx_buf;
> + hw->rx = t->rx_buf;
> + hw->count = 0;
> + hw->bytes_per_word = (t->bits_per_word ? : spi->bits_per_word) / 8;
> + hw->len = t->len / hw->bytes_per_word;
> +
> + if (hw->irq >= 0) {
> + init_completion(&hw->done);
I think you init this twice, once in altera_spi_probe
below as well.
> + /* enable receive interrupt */
> + hw->imr |= ALTERA_SPI_CONTROL_IRRDY_MSK;
> + writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
> +
> + /* send the first byte */
> + writel(hw_txbyte(hw, 0), hw->base + ALTERA_SPI_TXDATA);
> +
> + wait_for_completion(&hw->done);
> + /* disable receive interrupt */
> + hw->imr &= ~ALTERA_SPI_CONTROL_IRRDY_MSK;
> + writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
> + } else {
> + /* send the first byte */
> + writel(hw_txbyte(hw, 0), hw->base + ALTERA_SPI_TXDATA);
> +
> + while (1) {
> + unsigned int rxd;
> +
> + while (!(readl(hw->base + ALTERA_SPI_STATUS) &
> + ALTERA_SPI_STATUS_RRDY_MSK))
> + cpu_relax();
> +
> + rxd = readl(hw->base + ALTERA_SPI_RXDATA);
> + if (hw->rx) {
> + switch (hw->bytes_per_word) {
> + case 1:
> + hw->rx[hw->count] = rxd;
> + break;
> + case 2:
> + hw->rx[hw->count * 2] = rxd;
> + hw->rx[hw->count * 2 + 1] = rxd >> 8;
> + break;
> + }
> + }
> +
> + hw->count++;
> +
> + if (hw->count < hw->len)
> + writel(hw_txbyte(hw, hw->count),
> + hw->base + ALTERA_SPI_TXDATA);
> + else
> + break;
> + }
> +
> + }
> +
> + return hw->count * hw->bytes_per_word;
> +}
> +
> +static irqreturn_t altera_spi_irq(int irq, void *dev)
> +{
> + struct altera_spi *hw = dev;
> + unsigned int rxd;
> +
> + rxd = readl(hw->base + ALTERA_SPI_RXDATA);
> + if (hw->rx) {
> + switch (hw->bytes_per_word) {
> + case 1:
> + hw->rx[hw->count] = rxd;
> + break;
> + case 2:
> + hw->rx[hw->count * 2] = rxd;
> + hw->rx[hw->count * 2 + 1] = rxd >> 8;
> + break;
> + }
> + }
> +
> + hw->count++;
> +
> + if (hw->count < hw->len)
> + writel(hw_txbyte(hw, hw->count), hw->base + ALTERA_SPI_TXDATA);
> + else
> + complete(&hw->done);
> +
> + return IRQ_HANDLED;
> +}
> +
> +#ifdef CONFIG_OF
> +static int __devinit altera_spi_of_probe(struct platform_device *pdev,
> + struct altera_spi *hw)
> +{
> + const __be32 *val;
> +
> + hw->bitbang.master->dev.of_node = pdev->dev.of_node;
> + return 0;
> +}
> +#else
> +static int __devinit altera_spi_of_probe(struct platform_device *pdev,
> + struct altera_spi *hw)
> +{
> + return 0;
> +}
> +#endif
> +
> +static int __devinit altera_spi_probe(struct platform_device *pdev)
> +{
> + struct altera_spi_platform_data *platp = pdev->dev.platform_data;
> + struct altera_spi *hw;
> + struct spi_master *master;
> + struct resource *res;
> + int err = 0;
> +
> + master = spi_alloc_master(&pdev->dev, sizeof(struct altera_spi));
> + if (master == NULL) {
> + dev_err(&pdev->dev, "No memory for spi_master\n");
> + err = -ENOMEM;
> + goto err_no_mem;
> + }
> +
> + /* setup the master state. */
> + master->bus_num = pdev->id;
> + master->num_chipselect = 16;
> + master->mode_bits = SPI_CS_HIGH;
> + master->setup = altera_spi_setup;
> +
> + hw = spi_master_get_devdata(master);
> + platform_set_drvdata(pdev, hw);
> +
> + /* setup the state for the bitbang driver */
> + hw->bitbang.master = spi_master_get(master);
> + if (hw->bitbang.master == NULL) {
> + dev_err(&pdev->dev, "Cannot get device\n");
> + err = -ENODEV;
> + goto err_no_dev;
> + }
> + hw->bitbang.setup_transfer = altera_spi_setupxfer;
> + hw->bitbang.chipselect = altera_spi_chipsel;
> + hw->bitbang.txrx_bufs = altera_spi_txrx;
> +
> + /* find and map our resources */
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (res == NULL) {
> + dev_err(&pdev->dev, "Cannot get IORESOURCE_MEM\n");
> + err = -ENOENT;
> + goto err_no_iores;
> + }
> + hw->base = ioremap(res->start, (res->end - res->start) + 1);
> + if (hw->base == 0) {
> + dev_err(&pdev->dev, "Cannot map IO\n");
> + err = -ENXIO;
> + goto err_no_iomap;
> + }
> + /* program defaults into the registers */
> + hw->imr = 0; /* disable spi interrupts */
> + writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
> + writel(0, hw->base + ALTERA_SPI_STATUS); /* clear status reg */
> + if (readl(hw->base + ALTERA_SPI_STATUS) & ALTERA_SPI_STATUS_RRDY_MSK)
> + readl(hw->base + ALTERA_SPI_RXDATA); /* flush rxdata */
> + /* irq is optional */
> + hw->irq = platform_get_irq(pdev, 0);
> + if (hw->irq >= 0) {
> + init_completion(&hw->done);
> + err = request_irq(hw->irq, altera_spi_irq, 0, pdev->name, hw);
> + if (err) {
> + dev_err(&pdev->dev, "Cannot claim IRQ\n");
> + goto err_no_irq;
> + }
> + }
> + /* find platform data */
> + if (!platp) {
> + err = altera_spi_of_probe(pdev, hw);
> + if (err)
> + goto err_no_of;
> + }
> +
> + /* register our spi controller */
> + err = spi_bitbang_start(&hw->bitbang);
> + if (err) {
> + dev_err(&pdev->dev, "Failed to register SPI master\n");
> + goto err_register;
> + }
> + dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
> +
> + return 0;
> +
> +err_register:
> +err_no_of:
> + if (hw->irq >= 0)
> + free_irq(hw->irq, hw);
> +err_no_irq:
> + iounmap((void *)hw->base);
> +err_no_iomap:
> +err_no_iores:
> + spi_master_put(master);;
> +err_no_mem:
> +err_no_dev:
> + return err;
> +}
> +
> +static int __devexit altera_spi_remove(struct platform_device *dev)
> +{
> + struct altera_spi *hw = platform_get_drvdata(dev);
> + struct spi_master *master = hw->bitbang.master;
> +
> + spi_bitbang_stop(&hw->bitbang);
> +
> + if (hw->irq >= 0)
> + free_irq(hw->irq, hw);
> + iounmap((void *)hw->base);
> +
> + platform_set_drvdata(dev, NULL);
> + spi_master_put(master);
> + return 0;
> +}
> +
> +#ifdef CONFIG_OF
> +static struct of_device_id altera_spi_match[] = {
> + {
> + .compatible = "altera,spi_altera",
> + },
> + {},
> +}
> +MODULE_DEVICE_TABLE(of, altera_spi_match);
> +#endif
> +
> +static struct platform_driver altera_spidrv = {
> + .remove = __devexit_p(altera_spi_remove),
> + .driver = {
> + .name = DRV_NAME,
> + .owner = THIS_MODULE,
> + .pm = NULL,
> +#ifdef CONFIG_OF
> + .of_match_table = altera_spi_match,
> +#endif
> + },
> +};
> +
> +static int __init altera_spi_init(void)
> +{
> + return platform_driver_probe(&altera_spidrv, altera_spi_probe);
> +}
> +
> +static void __exit altera_spi_exit(void)
> +{
> + platform_driver_unregister(&altera_spidrv);
> +}
> +
> +module_init(altera_spi_init);
> +module_exit(altera_spi_exit);
> +
> +MODULE_DESCRIPTION("Altera SPI driver");
> +MODULE_AUTHOR("Thomas Chou <thomas@...ron.com.tw>");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:" DRV_NAME);
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