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Diffstat (limited to 'drivers/spi/spi-at91-usart.c')
-rw-r--r--drivers/spi/spi-at91-usart.c681
1 files changed, 681 insertions, 0 deletions
diff --git a/drivers/spi/spi-at91-usart.c b/drivers/spi/spi-at91-usart.c
new file mode 100644
index 000000000..9cd738682
--- /dev/null
+++ b/drivers/spi/spi-at91-usart.c
@@ -0,0 +1,681 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Driver for AT91 USART Controllers as SPI
+//
+// Copyright (C) 2018 Microchip Technology Inc.
+//
+// Author: Radu Pirea <radu.pirea@microchip.com>
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-direction.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/gpio/consumer.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+
+#include <linux/spi/spi.h>
+
+#define US_CR 0x00
+#define US_MR 0x04
+#define US_IER 0x08
+#define US_IDR 0x0C
+#define US_CSR 0x14
+#define US_RHR 0x18
+#define US_THR 0x1C
+#define US_BRGR 0x20
+#define US_VERSION 0xFC
+
+#define US_CR_RSTRX BIT(2)
+#define US_CR_RSTTX BIT(3)
+#define US_CR_RXEN BIT(4)
+#define US_CR_RXDIS BIT(5)
+#define US_CR_TXEN BIT(6)
+#define US_CR_TXDIS BIT(7)
+
+#define US_MR_SPI_MASTER 0x0E
+#define US_MR_CHRL GENMASK(7, 6)
+#define US_MR_CPHA BIT(8)
+#define US_MR_CPOL BIT(16)
+#define US_MR_CLKO BIT(18)
+#define US_MR_WRDBT BIT(20)
+#define US_MR_LOOP BIT(15)
+
+#define US_IR_RXRDY BIT(0)
+#define US_IR_TXRDY BIT(1)
+#define US_IR_OVRE BIT(5)
+
+#define US_BRGR_SIZE BIT(16)
+
+#define US_MIN_CLK_DIV 0x06
+#define US_MAX_CLK_DIV BIT(16)
+
+#define US_RESET (US_CR_RSTRX | US_CR_RSTTX)
+#define US_DISABLE (US_CR_RXDIS | US_CR_TXDIS)
+#define US_ENABLE (US_CR_RXEN | US_CR_TXEN)
+#define US_OVRE_RXRDY_IRQS (US_IR_OVRE | US_IR_RXRDY)
+
+#define US_INIT \
+ (US_MR_SPI_MASTER | US_MR_CHRL | US_MR_CLKO | US_MR_WRDBT)
+#define US_DMA_MIN_BYTES 16
+#define US_DMA_TIMEOUT (msecs_to_jiffies(1000))
+
+/* Register access macros */
+#define at91_usart_spi_readl(port, reg) \
+ readl_relaxed((port)->regs + US_##reg)
+#define at91_usart_spi_writel(port, reg, value) \
+ writel_relaxed((value), (port)->regs + US_##reg)
+
+#define at91_usart_spi_readb(port, reg) \
+ readb_relaxed((port)->regs + US_##reg)
+#define at91_usart_spi_writeb(port, reg, value) \
+ writeb_relaxed((value), (port)->regs + US_##reg)
+
+struct at91_usart_spi {
+ struct platform_device *mpdev;
+ struct spi_transfer *current_transfer;
+ void __iomem *regs;
+ struct device *dev;
+ struct clk *clk;
+
+ struct completion xfer_completion;
+
+ /*used in interrupt to protect data reading*/
+ spinlock_t lock;
+
+ phys_addr_t phybase;
+
+ int irq;
+ unsigned int current_tx_remaining_bytes;
+ unsigned int current_rx_remaining_bytes;
+
+ u32 spi_clk;
+ u32 status;
+
+ bool xfer_failed;
+ bool use_dma;
+};
+
+static void dma_callback(void *data)
+{
+ struct spi_controller *ctlr = data;
+ struct at91_usart_spi *aus = spi_master_get_devdata(ctlr);
+
+ at91_usart_spi_writel(aus, IER, US_IR_RXRDY);
+ aus->current_rx_remaining_bytes = 0;
+ complete(&aus->xfer_completion);
+}
+
+static bool at91_usart_spi_can_dma(struct spi_controller *ctrl,
+ struct spi_device *spi,
+ struct spi_transfer *xfer)
+{
+ struct at91_usart_spi *aus = spi_master_get_devdata(ctrl);
+
+ return aus->use_dma && xfer->len >= US_DMA_MIN_BYTES;
+}
+
+static int at91_usart_spi_configure_dma(struct spi_controller *ctlr,
+ struct at91_usart_spi *aus)
+{
+ struct dma_slave_config slave_config;
+ struct device *dev = &aus->mpdev->dev;
+ phys_addr_t phybase = aus->phybase;
+ dma_cap_mask_t mask;
+ int err = 0;
+
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_SLAVE, mask);
+
+ ctlr->dma_tx = dma_request_chan(dev, "tx");
+ if (IS_ERR_OR_NULL(ctlr->dma_tx)) {
+ if (IS_ERR(ctlr->dma_tx)) {
+ err = PTR_ERR(ctlr->dma_tx);
+ goto at91_usart_spi_error_clear;
+ }
+
+ dev_dbg(dev,
+ "DMA TX channel not available, SPI unable to use DMA\n");
+ err = -EBUSY;
+ goto at91_usart_spi_error_clear;
+ }
+
+ ctlr->dma_rx = dma_request_chan(dev, "rx");
+ if (IS_ERR_OR_NULL(ctlr->dma_rx)) {
+ if (IS_ERR(ctlr->dma_rx)) {
+ err = PTR_ERR(ctlr->dma_rx);
+ goto at91_usart_spi_error;
+ }
+
+ dev_dbg(dev,
+ "DMA RX channel not available, SPI unable to use DMA\n");
+ err = -EBUSY;
+ goto at91_usart_spi_error;
+ }
+
+ slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ slave_config.dst_addr = (dma_addr_t)phybase + US_THR;
+ slave_config.src_addr = (dma_addr_t)phybase + US_RHR;
+ slave_config.src_maxburst = 1;
+ slave_config.dst_maxburst = 1;
+ slave_config.device_fc = false;
+
+ slave_config.direction = DMA_DEV_TO_MEM;
+ if (dmaengine_slave_config(ctlr->dma_rx, &slave_config)) {
+ dev_err(&ctlr->dev,
+ "failed to configure rx dma channel\n");
+ err = -EINVAL;
+ goto at91_usart_spi_error;
+ }
+
+ slave_config.direction = DMA_MEM_TO_DEV;
+ if (dmaengine_slave_config(ctlr->dma_tx, &slave_config)) {
+ dev_err(&ctlr->dev,
+ "failed to configure tx dma channel\n");
+ err = -EINVAL;
+ goto at91_usart_spi_error;
+ }
+
+ aus->use_dma = true;
+ return 0;
+
+at91_usart_spi_error:
+ if (!IS_ERR_OR_NULL(ctlr->dma_tx))
+ dma_release_channel(ctlr->dma_tx);
+ if (!IS_ERR_OR_NULL(ctlr->dma_rx))
+ dma_release_channel(ctlr->dma_rx);
+ ctlr->dma_tx = NULL;
+ ctlr->dma_rx = NULL;
+
+at91_usart_spi_error_clear:
+ return err;
+}
+
+static void at91_usart_spi_release_dma(struct spi_controller *ctlr)
+{
+ if (ctlr->dma_rx)
+ dma_release_channel(ctlr->dma_rx);
+ if (ctlr->dma_tx)
+ dma_release_channel(ctlr->dma_tx);
+}
+
+static void at91_usart_spi_stop_dma(struct spi_controller *ctlr)
+{
+ if (ctlr->dma_rx)
+ dmaengine_terminate_all(ctlr->dma_rx);
+ if (ctlr->dma_tx)
+ dmaengine_terminate_all(ctlr->dma_tx);
+}
+
+static int at91_usart_spi_dma_transfer(struct spi_controller *ctlr,
+ struct spi_transfer *xfer)
+{
+ struct at91_usart_spi *aus = spi_master_get_devdata(ctlr);
+ struct dma_chan *rxchan = ctlr->dma_rx;
+ struct dma_chan *txchan = ctlr->dma_tx;
+ struct dma_async_tx_descriptor *rxdesc;
+ struct dma_async_tx_descriptor *txdesc;
+ dma_cookie_t cookie;
+
+ /* Disable RX interrupt */
+ at91_usart_spi_writel(aus, IDR, US_IR_RXRDY);
+
+ rxdesc = dmaengine_prep_slave_sg(rxchan,
+ xfer->rx_sg.sgl,
+ xfer->rx_sg.nents,
+ DMA_DEV_TO_MEM,
+ DMA_PREP_INTERRUPT |
+ DMA_CTRL_ACK);
+ if (!rxdesc)
+ goto at91_usart_spi_err_dma;
+
+ txdesc = dmaengine_prep_slave_sg(txchan,
+ xfer->tx_sg.sgl,
+ xfer->tx_sg.nents,
+ DMA_MEM_TO_DEV,
+ DMA_PREP_INTERRUPT |
+ DMA_CTRL_ACK);
+ if (!txdesc)
+ goto at91_usart_spi_err_dma;
+
+ rxdesc->callback = dma_callback;
+ rxdesc->callback_param = ctlr;
+
+ cookie = rxdesc->tx_submit(rxdesc);
+ if (dma_submit_error(cookie))
+ goto at91_usart_spi_err_dma;
+
+ cookie = txdesc->tx_submit(txdesc);
+ if (dma_submit_error(cookie))
+ goto at91_usart_spi_err_dma;
+
+ rxchan->device->device_issue_pending(rxchan);
+ txchan->device->device_issue_pending(txchan);
+
+ return 0;
+
+at91_usart_spi_err_dma:
+ /* Enable RX interrupt if something fails and fallback to PIO */
+ at91_usart_spi_writel(aus, IER, US_IR_RXRDY);
+ at91_usart_spi_stop_dma(ctlr);
+
+ return -ENOMEM;
+}
+
+static unsigned long at91_usart_spi_dma_timeout(struct at91_usart_spi *aus)
+{
+ return wait_for_completion_timeout(&aus->xfer_completion,
+ US_DMA_TIMEOUT);
+}
+
+static inline u32 at91_usart_spi_tx_ready(struct at91_usart_spi *aus)
+{
+ return aus->status & US_IR_TXRDY;
+}
+
+static inline u32 at91_usart_spi_rx_ready(struct at91_usart_spi *aus)
+{
+ return aus->status & US_IR_RXRDY;
+}
+
+static inline u32 at91_usart_spi_check_overrun(struct at91_usart_spi *aus)
+{
+ return aus->status & US_IR_OVRE;
+}
+
+static inline u32 at91_usart_spi_read_status(struct at91_usart_spi *aus)
+{
+ aus->status = at91_usart_spi_readl(aus, CSR);
+ return aus->status;
+}
+
+static inline void at91_usart_spi_tx(struct at91_usart_spi *aus)
+{
+ unsigned int len = aus->current_transfer->len;
+ unsigned int remaining = aus->current_tx_remaining_bytes;
+ const u8 *tx_buf = aus->current_transfer->tx_buf;
+
+ if (!remaining)
+ return;
+
+ if (at91_usart_spi_tx_ready(aus)) {
+ at91_usart_spi_writeb(aus, THR, tx_buf[len - remaining]);
+ aus->current_tx_remaining_bytes--;
+ }
+}
+
+static inline void at91_usart_spi_rx(struct at91_usart_spi *aus)
+{
+ int len = aus->current_transfer->len;
+ int remaining = aus->current_rx_remaining_bytes;
+ u8 *rx_buf = aus->current_transfer->rx_buf;
+
+ if (!remaining)
+ return;
+
+ rx_buf[len - remaining] = at91_usart_spi_readb(aus, RHR);
+ aus->current_rx_remaining_bytes--;
+}
+
+static inline void
+at91_usart_spi_set_xfer_speed(struct at91_usart_spi *aus,
+ struct spi_transfer *xfer)
+{
+ at91_usart_spi_writel(aus, BRGR,
+ DIV_ROUND_UP(aus->spi_clk, xfer->speed_hz));
+}
+
+static irqreturn_t at91_usart_spi_interrupt(int irq, void *dev_id)
+{
+ struct spi_controller *controller = dev_id;
+ struct at91_usart_spi *aus = spi_master_get_devdata(controller);
+
+ spin_lock(&aus->lock);
+ at91_usart_spi_read_status(aus);
+
+ if (at91_usart_spi_check_overrun(aus)) {
+ aus->xfer_failed = true;
+ at91_usart_spi_writel(aus, IDR, US_IR_OVRE | US_IR_RXRDY);
+ spin_unlock(&aus->lock);
+ return IRQ_HANDLED;
+ }
+
+ if (at91_usart_spi_rx_ready(aus)) {
+ at91_usart_spi_rx(aus);
+ spin_unlock(&aus->lock);
+ return IRQ_HANDLED;
+ }
+
+ spin_unlock(&aus->lock);
+
+ return IRQ_NONE;
+}
+
+static int at91_usart_spi_setup(struct spi_device *spi)
+{
+ struct at91_usart_spi *aus = spi_master_get_devdata(spi->controller);
+ u32 *ausd = spi->controller_state;
+ unsigned int mr = at91_usart_spi_readl(aus, MR);
+
+ if (spi->mode & SPI_CPOL)
+ mr |= US_MR_CPOL;
+ else
+ mr &= ~US_MR_CPOL;
+
+ if (spi->mode & SPI_CPHA)
+ mr |= US_MR_CPHA;
+ else
+ mr &= ~US_MR_CPHA;
+
+ if (spi->mode & SPI_LOOP)
+ mr |= US_MR_LOOP;
+ else
+ mr &= ~US_MR_LOOP;
+
+ if (!ausd) {
+ ausd = kzalloc(sizeof(*ausd), GFP_KERNEL);
+ if (!ausd)
+ return -ENOMEM;
+
+ spi->controller_state = ausd;
+ }
+
+ *ausd = mr;
+
+ dev_dbg(&spi->dev,
+ "setup: bpw %u mode 0x%x -> mr %d %08x\n",
+ spi->bits_per_word, spi->mode, spi->chip_select, mr);
+
+ return 0;
+}
+
+static int at91_usart_spi_transfer_one(struct spi_controller *ctlr,
+ struct spi_device *spi,
+ struct spi_transfer *xfer)
+{
+ struct at91_usart_spi *aus = spi_master_get_devdata(ctlr);
+ unsigned long dma_timeout = 0;
+ int ret = 0;
+
+ at91_usart_spi_set_xfer_speed(aus, xfer);
+ aus->xfer_failed = false;
+ aus->current_transfer = xfer;
+ aus->current_tx_remaining_bytes = xfer->len;
+ aus->current_rx_remaining_bytes = xfer->len;
+
+ while ((aus->current_tx_remaining_bytes ||
+ aus->current_rx_remaining_bytes) && !aus->xfer_failed) {
+ reinit_completion(&aus->xfer_completion);
+ if (at91_usart_spi_can_dma(ctlr, spi, xfer) &&
+ !ret) {
+ ret = at91_usart_spi_dma_transfer(ctlr, xfer);
+ if (ret)
+ continue;
+
+ dma_timeout = at91_usart_spi_dma_timeout(aus);
+
+ if (WARN_ON(dma_timeout == 0)) {
+ dev_err(&spi->dev, "DMA transfer timeout\n");
+ return -EIO;
+ }
+ aus->current_tx_remaining_bytes = 0;
+ } else {
+ at91_usart_spi_read_status(aus);
+ at91_usart_spi_tx(aus);
+ }
+
+ cpu_relax();
+ }
+
+ if (aus->xfer_failed) {
+ dev_err(aus->dev, "Overrun!\n");
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int at91_usart_spi_prepare_message(struct spi_controller *ctlr,
+ struct spi_message *message)
+{
+ struct at91_usart_spi *aus = spi_master_get_devdata(ctlr);
+ struct spi_device *spi = message->spi;
+ u32 *ausd = spi->controller_state;
+
+ at91_usart_spi_writel(aus, CR, US_ENABLE);
+ at91_usart_spi_writel(aus, IER, US_OVRE_RXRDY_IRQS);
+ at91_usart_spi_writel(aus, MR, *ausd);
+
+ return 0;
+}
+
+static int at91_usart_spi_unprepare_message(struct spi_controller *ctlr,
+ struct spi_message *message)
+{
+ struct at91_usart_spi *aus = spi_master_get_devdata(ctlr);
+
+ at91_usart_spi_writel(aus, CR, US_RESET | US_DISABLE);
+ at91_usart_spi_writel(aus, IDR, US_OVRE_RXRDY_IRQS);
+
+ return 0;
+}
+
+static void at91_usart_spi_cleanup(struct spi_device *spi)
+{
+ struct at91_usart_spi_device *ausd = spi->controller_state;
+
+ spi->controller_state = NULL;
+ kfree(ausd);
+}
+
+static void at91_usart_spi_init(struct at91_usart_spi *aus)
+{
+ at91_usart_spi_writel(aus, MR, US_INIT);
+ at91_usart_spi_writel(aus, CR, US_RESET | US_DISABLE);
+}
+
+static int at91_usart_gpio_setup(struct platform_device *pdev)
+{
+ struct gpio_descs *cs_gpios;
+
+ cs_gpios = devm_gpiod_get_array_optional(&pdev->dev, "cs", GPIOD_OUT_LOW);
+
+ if (IS_ERR(cs_gpios))
+ return PTR_ERR(cs_gpios);
+
+ return 0;
+}
+
+static int at91_usart_spi_probe(struct platform_device *pdev)
+{
+ struct resource *regs;
+ struct spi_controller *controller;
+ struct at91_usart_spi *aus;
+ struct clk *clk;
+ int irq;
+ int ret;
+
+ regs = platform_get_resource(to_platform_device(pdev->dev.parent),
+ IORESOURCE_MEM, 0);
+ if (!regs)
+ return -EINVAL;
+
+ irq = platform_get_irq(to_platform_device(pdev->dev.parent), 0);
+ if (irq < 0)
+ return irq;
+
+ clk = devm_clk_get(pdev->dev.parent, "usart");
+ if (IS_ERR(clk))
+ return PTR_ERR(clk);
+
+ ret = -ENOMEM;
+ controller = spi_alloc_master(&pdev->dev, sizeof(*aus));
+ if (!controller)
+ goto at91_usart_spi_probe_fail;
+
+ ret = at91_usart_gpio_setup(pdev);
+ if (ret)
+ goto at91_usart_spi_probe_fail;
+
+ controller->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP | SPI_CS_HIGH;
+ controller->dev.of_node = pdev->dev.parent->of_node;
+ controller->bits_per_word_mask = SPI_BPW_MASK(8);
+ controller->setup = at91_usart_spi_setup;
+ controller->flags = SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX;
+ controller->transfer_one = at91_usart_spi_transfer_one;
+ controller->prepare_message = at91_usart_spi_prepare_message;
+ controller->unprepare_message = at91_usart_spi_unprepare_message;
+ controller->can_dma = at91_usart_spi_can_dma;
+ controller->cleanup = at91_usart_spi_cleanup;
+ controller->max_speed_hz = DIV_ROUND_UP(clk_get_rate(clk),
+ US_MIN_CLK_DIV);
+ controller->min_speed_hz = DIV_ROUND_UP(clk_get_rate(clk),
+ US_MAX_CLK_DIV);
+ platform_set_drvdata(pdev, controller);
+
+ aus = spi_master_get_devdata(controller);
+
+ aus->dev = &pdev->dev;
+ aus->regs = devm_ioremap_resource(&pdev->dev, regs);
+ if (IS_ERR(aus->regs)) {
+ ret = PTR_ERR(aus->regs);
+ goto at91_usart_spi_probe_fail;
+ }
+
+ aus->irq = irq;
+ aus->clk = clk;
+
+ ret = devm_request_irq(&pdev->dev, irq, at91_usart_spi_interrupt, 0,
+ dev_name(&pdev->dev), controller);
+ if (ret)
+ goto at91_usart_spi_probe_fail;
+
+ ret = clk_prepare_enable(clk);
+ if (ret)
+ goto at91_usart_spi_probe_fail;
+
+ aus->spi_clk = clk_get_rate(clk);
+ at91_usart_spi_init(aus);
+
+ aus->phybase = regs->start;
+
+ aus->mpdev = to_platform_device(pdev->dev.parent);
+
+ ret = at91_usart_spi_configure_dma(controller, aus);
+ if (ret)
+ goto at91_usart_fail_dma;
+
+ spin_lock_init(&aus->lock);
+ init_completion(&aus->xfer_completion);
+
+ ret = devm_spi_register_master(&pdev->dev, controller);
+ if (ret)
+ goto at91_usart_fail_register_master;
+
+ dev_info(&pdev->dev,
+ "AT91 USART SPI Controller version 0x%x at %pa (irq %d)\n",
+ at91_usart_spi_readl(aus, VERSION),
+ &regs->start, irq);
+
+ return 0;
+
+at91_usart_fail_register_master:
+ at91_usart_spi_release_dma(controller);
+at91_usart_fail_dma:
+ clk_disable_unprepare(clk);
+at91_usart_spi_probe_fail:
+ spi_master_put(controller);
+ return ret;
+}
+
+__maybe_unused static int at91_usart_spi_runtime_suspend(struct device *dev)
+{
+ struct spi_controller *ctlr = dev_get_drvdata(dev);
+ struct at91_usart_spi *aus = spi_master_get_devdata(ctlr);
+
+ clk_disable_unprepare(aus->clk);
+ pinctrl_pm_select_sleep_state(dev);
+
+ return 0;
+}
+
+__maybe_unused static int at91_usart_spi_runtime_resume(struct device *dev)
+{
+ struct spi_controller *ctrl = dev_get_drvdata(dev);
+ struct at91_usart_spi *aus = spi_master_get_devdata(ctrl);
+
+ pinctrl_pm_select_default_state(dev);
+
+ return clk_prepare_enable(aus->clk);
+}
+
+__maybe_unused static int at91_usart_spi_suspend(struct device *dev)
+{
+ struct spi_controller *ctrl = dev_get_drvdata(dev);
+ int ret;
+
+ ret = spi_controller_suspend(ctrl);
+ if (ret)
+ return ret;
+
+ if (!pm_runtime_suspended(dev))
+ at91_usart_spi_runtime_suspend(dev);
+
+ return 0;
+}
+
+__maybe_unused static int at91_usart_spi_resume(struct device *dev)
+{
+ struct spi_controller *ctrl = dev_get_drvdata(dev);
+ struct at91_usart_spi *aus = spi_master_get_devdata(ctrl);
+ int ret;
+
+ if (!pm_runtime_suspended(dev)) {
+ ret = at91_usart_spi_runtime_resume(dev);
+ if (ret)
+ return ret;
+ }
+
+ at91_usart_spi_init(aus);
+
+ return spi_controller_resume(ctrl);
+}
+
+static int at91_usart_spi_remove(struct platform_device *pdev)
+{
+ struct spi_controller *ctlr = platform_get_drvdata(pdev);
+ struct at91_usart_spi *aus = spi_master_get_devdata(ctlr);
+
+ at91_usart_spi_release_dma(ctlr);
+ clk_disable_unprepare(aus->clk);
+
+ return 0;
+}
+
+static const struct dev_pm_ops at91_usart_spi_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(at91_usart_spi_suspend, at91_usart_spi_resume)
+ SET_RUNTIME_PM_OPS(at91_usart_spi_runtime_suspend,
+ at91_usart_spi_runtime_resume, NULL)
+};
+
+static struct platform_driver at91_usart_spi_driver = {
+ .driver = {
+ .name = "at91_usart_spi",
+ .pm = &at91_usart_spi_pm_ops,
+ },
+ .probe = at91_usart_spi_probe,
+ .remove = at91_usart_spi_remove,
+};
+
+module_platform_driver(at91_usart_spi_driver);
+
+MODULE_DESCRIPTION("Microchip AT91 USART SPI Controller driver");
+MODULE_AUTHOR("Radu Pirea <radu.pirea@microchip.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:at91_usart_spi");