[PATCH] SPI: atmel_spi driver

Driver for the Atmel on-chip SPI master controller.

Tested primarily on AVR32/AT32AP7000/ATSTK1000 using mtd_dataflash and the
jffs2 filesystem.  Should also work fine on various AT91 ARM-based chips
like AT91SAM926x and AT91RM9200.

Hardware documentation can be found in the AT32AP7000 data sheet, or its
AT91 siblings, which can be downloaded from

http://www.atmel.com/dyn/products/datasheets.asp?family_id=682

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 678 insertions, 0 deletions

diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c
new file mode 100644
index 00000000000..c2a9fef58ed
--- /dev/null
+++ b/drivers/spi/atmel_spi.c
@@ -0,0 +1,678 @@
+/*
+ * Driver for Atmel AT32 and AT91 SPI Controllers
+ *
+ * Copyright (C) 2006 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/spi/spi.h>
+
+#include <asm/io.h>
+#include <asm/arch/board.h>
+#include <asm/arch/gpio.h>
+
+#include "atmel_spi.h"
+
+/*
+ * The core SPI transfer engine just talks to a register bank to set up
+ * DMA transfers; transfer queue progress is driven by IRQs.  The clock
+ * framework provides the base clock, subdivided for each spi_device.
+ *
+ * Newer controllers, marked with "new_1" flag, have:
+ *  - CR.LASTXFER
+ *  - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero)
+ *  - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
+ *  - SPI_CSRx.CSAAT
+ *  - SPI_CSRx.SBCR allows faster clocking
+ */
+struct atmel_spi {
+	spinlock_t		lock;
+
+	void __iomem		*regs;
+	int			irq;
+	struct clk		*clk;
+	struct platform_device	*pdev;
+	unsigned		new_1:1;
+
+	u8			stopping;
+	struct list_head	queue;
+	struct spi_transfer	*current_transfer;
+	unsigned long		remaining_bytes;
+
+	void			*buffer;
+	dma_addr_t		buffer_dma;
+};
+
+#define BUFFER_SIZE		PAGE_SIZE
+#define INVALID_DMA_ADDRESS	0xffffffff
+
+/*
+ * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
+ * they assume that spi slave device state will not change on deselect, so
+ * that automagic deselection is OK.  Not so!  Workaround uses nCSx pins
+ * as GPIOs; or newer controllers have CSAAT and friends.
+ *
+ * Since the CSAAT functionality is a bit weird on newer controllers
+ * as well, we use GPIO to control nCSx pins on all controllers.
+ */
+
+static inline void cs_activate(struct spi_device *spi)
+{
+	unsigned gpio = (unsigned) spi->controller_data;
+	unsigned active = spi->mode & SPI_CS_HIGH;
+
+	dev_dbg(&spi->dev, "activate %u%s\n", gpio, active ? " (high)" : "");
+	gpio_set_value(gpio, active);
+}
+
+static inline void cs_deactivate(struct spi_device *spi)
+{
+	unsigned gpio = (unsigned) spi->controller_data;
+	unsigned active = spi->mode & SPI_CS_HIGH;
+
+	dev_dbg(&spi->dev, "DEactivate %u%s\n", gpio, active ? " (low)" : "");
+	gpio_set_value(gpio, !active);
+}
+
+/*
+ * Submit next transfer for DMA.
+ * lock is held, spi irq is blocked
+ */
+static void atmel_spi_next_xfer(struct spi_master *master,
+				struct spi_message *msg)
+{
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+	struct spi_transfer	*xfer;
+	u32			len;
+	dma_addr_t		tx_dma, rx_dma;
+
+	xfer = as->current_transfer;
+	if (!xfer || as->remaining_bytes == 0) {
+		if (xfer)
+			xfer = list_entry(xfer->transfer_list.next,
+					struct spi_transfer, transfer_list);
+		else
+			xfer = list_entry(msg->transfers.next,
+					struct spi_transfer, transfer_list);
+		as->remaining_bytes = xfer->len;
+		as->current_transfer = xfer;
+	}
+
+	len = as->remaining_bytes;
+
+	tx_dma = xfer->tx_dma;
+	rx_dma = xfer->rx_dma;
+
+	/* use scratch buffer only when rx or tx data is unspecified */
+	if (rx_dma == INVALID_DMA_ADDRESS) {
+		rx_dma = as->buffer_dma;
+		if (len > BUFFER_SIZE)
+			len = BUFFER_SIZE;
+	}
+	if (tx_dma == INVALID_DMA_ADDRESS) {
+		tx_dma = as->buffer_dma;
+		if (len > BUFFER_SIZE)
+			len = BUFFER_SIZE;
+		memset(as->buffer, 0, len);
+		dma_sync_single_for_device(&as->pdev->dev,
+				as->buffer_dma, len, DMA_TO_DEVICE);
+	}
+
+	spi_writel(as, RPR, rx_dma);
+	spi_writel(as, TPR, tx_dma);
+
+	as->remaining_bytes -= len;
+	if (msg->spi->bits_per_word > 8)
+		len >>= 1;
+
+	/* REVISIT: when xfer->delay_usecs == 0, the PDC "next transfer"
+	 * mechanism might help avoid the IRQ latency between transfers
+	 *
+	 * We're also waiting for ENDRX before we start the next
+	 * transfer because we need to handle some difficult timing
+	 * issues otherwise. If we wait for ENDTX in one transfer and
+	 * then starts waiting for ENDRX in the next, it's difficult
+	 * to tell the difference between the ENDRX interrupt we're
+	 * actually waiting for and the ENDRX interrupt of the
+	 * previous transfer.
+	 *
+	 * It should be doable, though. Just not now...
+	 */
+	spi_writel(as, TNCR, 0);
+	spi_writel(as, RNCR, 0);
+	spi_writel(as, IER, SPI_BIT(ENDRX) | SPI_BIT(OVRES));
+
+	dev_dbg(&msg->spi->dev,
+		"  start xfer %p: len %u tx %p/%08x rx %p/%08x imr %03x\n",
+		xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
+		xfer->rx_buf, xfer->rx_dma, spi_readl(as, IMR));
+
+	spi_writel(as, TCR, len);
+	spi_writel(as, RCR, len);
+	spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
+}
+
+static void atmel_spi_next_message(struct spi_master *master)
+{
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+	struct spi_message	*msg;
+	u32			mr;
+
+	BUG_ON(as->current_transfer);
+
+	msg = list_entry(as->queue.next, struct spi_message, queue);
+
+	/* Select the chip */
+	mr = spi_readl(as, MR);
+	mr = SPI_BFINS(PCS, ~(1 << msg->spi->chip_select), mr);
+	spi_writel(as, MR, mr);
+	cs_activate(msg->spi);
+
+	atmel_spi_next_xfer(master, msg);
+}
+
+static void
+atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
+{
+	xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
+	if (xfer->tx_buf)
+		xfer->tx_dma = dma_map_single(&as->pdev->dev,
+				(void *) xfer->tx_buf, xfer->len,
+				DMA_TO_DEVICE);
+	if (xfer->rx_buf)
+		xfer->rx_dma = dma_map_single(&as->pdev->dev,
+				xfer->rx_buf, xfer->len,
+				DMA_FROM_DEVICE);
+}
+
+static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
+				     struct spi_transfer *xfer)
+{
+	if (xfer->tx_dma != INVALID_DMA_ADDRESS)
+		dma_unmap_single(master->cdev.dev, xfer->tx_dma,
+				 xfer->len, DMA_TO_DEVICE);
+	if (xfer->rx_dma != INVALID_DMA_ADDRESS)
+		dma_unmap_single(master->cdev.dev, xfer->rx_dma,
+				 xfer->len, DMA_FROM_DEVICE);
+}
+
+static void
+atmel_spi_msg_done(struct spi_master *master, struct atmel_spi *as,
+		   struct spi_message *msg, int status)
+{
+	cs_deactivate(msg->spi);
+	list_del(&msg->queue);
+	msg->status = status;
+
+	dev_dbg(master->cdev.dev,
+		"xfer complete: %u bytes transferred\n",
+		msg->actual_length);
+
+	spin_unlock(&as->lock);
+	msg->complete(msg->context);
+	spin_lock(&as->lock);
+
+	as->current_transfer = NULL;
+
+	/* continue if needed */
+	if (list_empty(&as->queue) || as->stopping)
+		spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
+	else
+		atmel_spi_next_message(master);
+}
+
+static irqreturn_t
+atmel_spi_interrupt(int irq, void *dev_id)
+{
+	struct spi_master	*master = dev_id;
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+	struct spi_message	*msg;
+	struct spi_transfer	*xfer;
+	u32			status, pending, imr;
+	int			ret = IRQ_NONE;
+
+	spin_lock(&as->lock);
+
+	xfer = as->current_transfer;
+	msg = list_entry(as->queue.next, struct spi_message, queue);
+
+	imr = spi_readl(as, IMR);
+	status = spi_readl(as, SR);
+	pending = status & imr;
+
+	if (pending & SPI_BIT(OVRES)) {
+		int timeout;
+
+		ret = IRQ_HANDLED;
+
+		spi_writel(as, IDR, (SPI_BIT(ENDTX) | SPI_BIT(ENDRX)
+				     | SPI_BIT(OVRES)));
+
+		/*
+		 * When we get an overrun, we disregard the current
+		 * transfer. Data will not be copied back from any
+		 * bounce buffer and msg->actual_len will not be
+		 * updated with the last xfer.
+		 *
+		 * We will also not process any remaning transfers in
+		 * the message.
+		 *
+		 * First, stop the transfer and unmap the DMA buffers.
+		 */
+		spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
+		if (!msg->is_dma_mapped)
+			atmel_spi_dma_unmap_xfer(master, xfer);
+
+		/* REVISIT: udelay in irq is unfriendly */
+		if (xfer->delay_usecs)
+			udelay(xfer->delay_usecs);
+
+		dev_warn(master->cdev.dev, "fifo overrun (%u/%u remaining)\n",
+			 spi_readl(as, TCR), spi_readl(as, RCR));
+
+		/*
+		 * Clean up DMA registers and make sure the data
+		 * registers are empty.
+		 */
+		spi_writel(as, RNCR, 0);
+		spi_writel(as, TNCR, 0);
+		spi_writel(as, RCR, 0);
+		spi_writel(as, TCR, 0);
+		for (timeout = 1000; timeout; timeout--)
+			if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
+				break;
+		if (!timeout)
+			dev_warn(master->cdev.dev,
+				 "timeout waiting for TXEMPTY");
+		while (spi_readl(as, SR) & SPI_BIT(RDRF))
+			spi_readl(as, RDR);
+
+		/* Clear any overrun happening while cleaning up */
+		spi_readl(as, SR);
+
+		atmel_spi_msg_done(master, as, msg, -EIO);
+	} else if (pending & SPI_BIT(ENDRX)) {
+		ret = IRQ_HANDLED;
+
+		spi_writel(as, IDR, pending);
+
+		if (as->remaining_bytes == 0) {
+			msg->actual_length += xfer->len;
+
+			if (!msg->is_dma_mapped)
+				atmel_spi_dma_unmap_xfer(master, xfer);
+
+			/* REVISIT: udelay in irq is unfriendly */
+			if (xfer->delay_usecs)
+				udelay(xfer->delay_usecs);
+
+			if (msg->transfers.prev == &xfer->transfer_list) {
+				/* report completed message */
+				atmel_spi_msg_done(master, as, msg, 0);
+			} else {
+				if (xfer->cs_change) {
+					cs_deactivate(msg->spi);
+					udelay(1);
+					cs_activate(msg->spi);
+				}
+
+				/*
+				 * Not done yet. Submit the next transfer.
+				 *
+				 * FIXME handle protocol options for xfer
+				 */
+				atmel_spi_next_xfer(master, msg);
+			}
+		} else {
+			/*
+			 * Keep going, we still have data to send in
+			 * the current transfer.
+			 */
+			atmel_spi_next_xfer(master, msg);
+		}
+	}
+
+	spin_unlock(&as->lock);
+
+	return ret;
+}
+
+#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
+
+static int atmel_spi_setup(struct spi_device *spi)
+{
+	struct atmel_spi	*as;
+	u32			scbr, csr;
+	unsigned int		bits = spi->bits_per_word;
+	unsigned long		bus_hz, sck_hz;
+	unsigned int		npcs_pin;
+	int			ret;
+
+	as = spi_master_get_devdata(spi->master);
+
+	if (as->stopping)
+		return -ESHUTDOWN;
+
+	if (spi->chip_select > spi->master->num_chipselect) {
+		dev_dbg(&spi->dev,
+				"setup: invalid chipselect %u (%u defined)\n",
+				spi->chip_select, spi->master->num_chipselect);
+		return -EINVAL;
+	}
+
+	if (bits == 0)
+		bits = 8;
+	if (bits < 8 || bits > 16) {
+		dev_dbg(&spi->dev,
+				"setup: invalid bits_per_word %u (8 to 16)\n",
+				bits);
+		return -EINVAL;
+	}
+
+	if (spi->mode & ~MODEBITS) {
+		dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
+			spi->mode & ~MODEBITS);
+		return -EINVAL;
+	}
+
+	/* speed zero convention is used by some upper layers */
+	bus_hz = clk_get_rate(as->clk);
+	if (spi->max_speed_hz) {
+		/* assume div32/fdiv/mbz == 0 */
+		if (!as->new_1)
+			bus_hz /= 2;
+		scbr = ((bus_hz + spi->max_speed_hz - 1)
+			/ spi->max_speed_hz);
+		if (scbr >= (1 << SPI_SCBR_SIZE)) {
+			dev_dbg(&spi->dev, "setup: %d Hz too slow, scbr %u\n",
+					spi->max_speed_hz, scbr);
+			return -EINVAL;
+		}
+	} else
+		scbr = 0xff;
+	sck_hz = bus_hz / scbr;
+
+	csr = SPI_BF(SCBR, scbr) | SPI_BF(BITS, bits - 8);
+	if (spi->mode & SPI_CPOL)
+		csr |= SPI_BIT(CPOL);
+	if (!(spi->mode & SPI_CPHA))
+		csr |= SPI_BIT(NCPHA);
+
+	/* TODO: DLYBS and DLYBCT */
+	csr |= SPI_BF(DLYBS, 10);
+	csr |= SPI_BF(DLYBCT, 10);
+
+	/* chipselect must have been muxed as GPIO (e.g. in board setup) */
+	npcs_pin = (unsigned int)spi->controller_data;
+	if (!spi->controller_state) {
+		ret = gpio_request(npcs_pin, "spi_npcs");
+		if (ret)
+			return ret;
+		spi->controller_state = (void *)npcs_pin;
+		gpio_direction_output(npcs_pin);
+	}
+
+	dev_dbg(&spi->dev,
+		"setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n",
+		sck_hz, bits, spi->mode, spi->chip_select, csr);
+
+	spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
+
+	return 0;
+}
+
+static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg)
+{
+	struct atmel_spi	*as;
+	struct spi_transfer	*xfer;
+	unsigned long		flags;
+	struct device		*controller = spi->master->cdev.dev;
+
+	as = spi_master_get_devdata(spi->master);
+
+	dev_dbg(controller, "new message %p submitted for %s\n",
+			msg, spi->dev.bus_id);
+
+	if (unlikely(list_empty(&msg->transfers)
+			|| !spi->max_speed_hz))
+		return -EINVAL;
+
+	if (as->stopping)
+		return -ESHUTDOWN;
+
+	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+		if (!(xfer->tx_buf || xfer->rx_buf)) {
+			dev_dbg(&spi->dev, "missing rx or tx buf\n");
+			return -EINVAL;
+		}
+
+		/* FIXME implement these protocol options!! */
+		if (xfer->bits_per_word || xfer->speed_hz) {
+			dev_dbg(&spi->dev, "no protocol options yet\n");
+			return -ENOPROTOOPT;
+		}
+	}
+
+	/* scrub dcache "early" */
+	if (!msg->is_dma_mapped) {
+		list_for_each_entry(xfer, &msg->transfers, transfer_list)
+			atmel_spi_dma_map_xfer(as, xfer);
+	}
+
+	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+		dev_dbg(controller,
+			"  xfer %p: len %u tx %p/%08x rx %p/%08x\n",
+			xfer, xfer->len,
+			xfer->tx_buf, xfer->tx_dma,
+			xfer->rx_buf, xfer->rx_dma);
+	}
+
+	msg->status = -EINPROGRESS;
+	msg->actual_length = 0;
+
+	spin_lock_irqsave(&as->lock, flags);
+	list_add_tail(&msg->queue, &as->queue);
+	if (!as->current_transfer)
+		atmel_spi_next_message(spi->master);
+	spin_unlock_irqrestore(&as->lock, flags);
+
+	return 0;
+}
+
+static void atmel_spi_cleanup(const struct spi_device *spi)
+{
+	if (spi->controller_state)
+		gpio_free((unsigned int)spi->controller_data);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int __init 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;
+
+	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!regs)
+		return -ENXIO;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	clk = clk_get(&pdev->dev, "spi_clk");
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	/* setup spi core then atmel-specific driver state */
+	ret = -ENOMEM;
+	master = spi_alloc_master(&pdev->dev, sizeof *as);
+	if (!master)
+		goto out_free;
+
+	master->bus_num = pdev->id;
+	master->num_chipselect = 4;
+	master->setup = atmel_spi_setup;
+	master->transfer = atmel_spi_transfer;
+	master->cleanup = atmel_spi_cleanup;
+	platform_set_drvdata(pdev, master);
+
+	as = spi_master_get_devdata(master);
+
+	as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE,
+					&as->buffer_dma, GFP_KERNEL);
+	if (!as->buffer)
+		goto out_free;
+
+	spin_lock_init(&as->lock);
+	INIT_LIST_HEAD(&as->queue);
+	as->pdev = pdev;
+	as->regs = ioremap(regs->start, (regs->end - regs->start) + 1);
+	if (!as->regs)
+		goto out_free_buffer;
+	as->irq = irq;
+	as->clk = clk;
+#ifdef CONFIG_ARCH_AT91
+	if (!cpu_is_at91rm9200())
+		as->new_1 = 1;
+#endif
+
+	ret = request_irq(irq, atmel_spi_interrupt, 0,
+			pdev->dev.bus_id, master);
+	if (ret)
+		goto out_unmap_regs;
+
+	/* Initialize the hardware */
+	clk_enable(clk);
+	spi_writel(as, CR, SPI_BIT(SWRST));
+	spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
+	spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
+	spi_writel(as, CR, SPI_BIT(SPIEN));
+
+	/* go! */
+	dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
+			(unsigned long)regs->start, irq);
+
+	ret = spi_register_master(master);
+	if (ret)
+		goto out_reset_hw;
+
+	return 0;
+
+out_reset_hw:
+	spi_writel(as, CR, SPI_BIT(SWRST));
+	clk_disable(clk);
+	free_irq(irq, master);
+out_unmap_regs:
+	iounmap(as->regs);
+out_free_buffer:
+	dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
+			as->buffer_dma);
+out_free:
+	clk_put(clk);
+	spi_master_put(master);
+	return ret;
+}
+
+static int __exit atmel_spi_remove(struct platform_device *pdev)
+{
+	struct spi_master	*master = platform_get_drvdata(pdev);
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+	struct spi_message	*msg;
+
+	/* reset the hardware and block queue progress */
+	spin_lock_irq(&as->lock);
+	as->stopping = 1;
+	spi_writel(as, CR, SPI_BIT(SWRST));
+	spi_readl(as, SR);
+	spin_unlock_irq(&as->lock);
+
+	/* Terminate remaining queued transfers */
+	list_for_each_entry(msg, &as->queue, queue) {
+		/* REVISIT unmapping the dma is a NOP on ARM and AVR32
+		 * but we shouldn't depend on that...
+		 */
+		msg->status = -ESHUTDOWN;
+		msg->complete(msg->context);
+	}
+
+	dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
+			as->buffer_dma);
+
+	clk_disable(as->clk);
+	clk_put(as->clk);
+	free_irq(as->irq, master);
+	iounmap(as->regs);
+
+	spi_unregister_master(master);
+
+	return 0;
+}
+
+#ifdef	CONFIG_PM
+
+static int atmel_spi_suspend(struct platform_device *pdev, pm_message_t mesg)
+{
+	struct spi_master	*master = platform_get_drvdata(pdev);
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+
+	clk_disable(as->clk);
+	return 0;
+}
+
+static int atmel_spi_resume(struct platform_device *pdev)
+{
+	struct spi_master	*master = platform_get_drvdata(pdev);
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+
+	clk_enable(as->clk);
+	return 0;
+}
+
+#else
+#define	atmel_spi_suspend	NULL
+#define	atmel_spi_resume	NULL
+#endif
+
+
+static struct platform_driver atmel_spi_driver = {
+	.driver		= {
+		.name	= "atmel_spi",
+		.owner	= THIS_MODULE,
+	},
+	.suspend	= atmel_spi_suspend,
+	.resume		= atmel_spi_resume,
+	.remove		= __exit_p(atmel_spi_remove),
+};
+
+static int __init atmel_spi_init(void)
+{
+	return platform_driver_probe(&atmel_spi_driver, atmel_spi_probe);
+}
+module_init(atmel_spi_init);
+
+static void __exit atmel_spi_exit(void)
+{
+	platform_driver_unregister(&atmel_spi_driver);
+}
+module_exit(atmel_spi_exit);
+
+MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
+MODULE_AUTHOR("Haavard Skinnemoen <hskinnemoen@atmel.com>");
+MODULE_LICENSE("GPL");