From patchwork Fri May 11 10:38:21 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Radu Pirea X-Patchwork-Id: 10393909 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 9C8EB60236 for ; Fri, 11 May 2018 10:41:46 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BD53028E6F for ; Fri, 11 May 2018 10:41:46 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B142F28E71; Fri, 11 May 2018 10:41:46 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 98F3528E6F for ; Fri, 11 May 2018 10:41:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=qfILOK0Q50JAh9uFbePfsKqOemGD3MOrmlvJB/lhzvY=; b=bZ6V+niHa7lbUZ 6Jq7NT1LB8Y9T5/EzbEBnNE178kp/ahsgnNbm5Mnh04ZzXx1v/NE5mUr7O7EL80oAvb/ErBRBl1ce o9OZTpow6fKtRLtq1g85akWzrNrxKJ8Z8ISWrM9RbsQVJqYgat1+22rOcfSKEIMhbwWyBDXdqgSfq aOx6StdOFIebWOGl+Uv32mey8Hwp/x8eXXjC8IMB+AG02UaXsbFljDBU4fwoSCdQ6rIfT0zRBsosw 1DjqCo505NLI3GAnomJ1NWKjjqo3Av3Whnba0PdPlX+zD8vFBLnMbSEOP+2AHK8PJ0ifXhnDx3ySI vYqLYJDSJG5FOVBGDZjg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fH5UX-0006AZ-M9; Fri, 11 May 2018 10:41:37 +0000 Received: from esa5.microchip.iphmx.com ([216.71.150.166]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1fH5Qq-0002wi-CR for linux-arm-kernel@lists.infradead.org; Fri, 11 May 2018 10:37:51 +0000 X-IronPort-AV: E=Sophos;i="5.49,388,1520924400"; d="scan'208";a="11960904" Received: from smtpout.microchip.com (HELO email.microchip.com) ([198.175.253.82]) by esa5.microchip.iphmx.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 11 May 2018 03:37:37 -0700 Received: from m19893.microchip.com (10.10.76.4) by chn-sv-exch05.mchp-main.com (10.10.76.106) with Microsoft SMTP Server id 14.3.352.0; Fri, 11 May 2018 03:37:36 -0700 From: Radu Pirea To: , , , , Subject: [PATCH v3 5/6] spi: at91-usart: add driver for at91-usart as spi Date: Fri, 11 May 2018 13:38:21 +0300 Message-ID: <20180511103822.31698-6-radu.pirea@microchip.com> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180511103822.31698-1-radu.pirea@microchip.com> References: <20180511103822.31698-1-radu.pirea@microchip.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180511_033749_080967_215B101E X-CRM114-Status: GOOD ( 16.94 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, alexandre.belloni@bootlin.com, richard.genoud@gmail.com, gregkh@linuxfoundation.org, broonie@kernel.org, robh+dt@kernel.org, jslaby@suse.com, Radu Pirea , lee.jones@linaro.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP This is the driver for at91-usart in spi mode. The USART IP can be configured to work in many modes and one of them is SPI. The driver was tested on sama5d3-xplained and sama5d4-xplained boards with enc28j60 ethernet controller as slave. Signed-off-by: Radu Pirea --- drivers/spi/Kconfig | 9 + drivers/spi/Makefile | 1 + drivers/spi/spi-at91-usart.c | 544 +++++++++++++++++++++++++++++++++++ 3 files changed, 554 insertions(+) create mode 100644 drivers/spi/spi-at91-usart.c diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index 6fb0347a24f2..c675e6b8dd5a 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -77,6 +77,15 @@ config SPI_ATMEL This selects a driver for the Atmel SPI Controller, present on many AT91 (ARM) chips. +config SPI_AT91_USART + tristate "Atmel USART Controller as SPI" + depends on HAS_DMA + depends on (ARCH_AT91 || COMPILE_TEST) + select MFD_AT91_USART + help + This selects a driver for the AT91 USART Controller as SPI Master, + present on AT91 and SAMA5 SoC series. + config SPI_AU1550 tristate "Au1550/Au1200/Au1300 SPI Controller" depends on MIPS_ALCHEMY diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index 34c5f2832ddf..fb6cb42f4eaa 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -15,6 +15,7 @@ obj-$(CONFIG_SPI_LOOPBACK_TEST) += spi-loopback-test.o obj-$(CONFIG_SPI_ALTERA) += spi-altera.o obj-$(CONFIG_SPI_ARMADA_3700) += spi-armada-3700.o obj-$(CONFIG_SPI_ATMEL) += spi-atmel.o +obj-$(CONFIG_SPI_AT91_USART) += spi-at91-usart.o obj-$(CONFIG_SPI_ATH79) += spi-ath79.o obj-$(CONFIG_SPI_AU1550) += spi-au1550.o obj-$(CONFIG_SPI_AXI_SPI_ENGINE) += spi-axi-spi-engine.o diff --git a/drivers/spi/spi-at91-usart.c b/drivers/spi/spi-at91-usart.c new file mode 100644 index 000000000000..79a59759d2ee --- /dev/null +++ b/drivers/spi/spi-at91-usart.c @@ -0,0 +1,544 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Driver for AT91 USART Controllers as SPI + * + * Copyright (C) 2018 Microchip Technology Inc. + * Author: Radu Pirea + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include + +#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_DUMMY_TX 0xFF + +/* Register access macros */ +#define spi_readl(port, reg) \ + readl_relaxed((port)->regs + US_##reg) +#define spi_writel(port, reg, value) \ + writel_relaxed((value), (port)->regs + US_##reg) + +#define spi_readb(port, reg) \ + readb_relaxed((port)->regs + US_##reg) +#define spi_writeb(port, reg, value) \ + writeb_relaxed((value), (port)->regs + US_##reg) + +struct at91_usart_spi { + struct spi_transfer *current_transfer; + void __iomem *regs; + struct device *dev; + struct clk *clk; + + /*used in interrupt to protect data reading*/ + spinlock_t lock; + + int irq; + unsigned int current_tx_remaining_bytes; + unsigned int current_rx_remaining_bytes; + int done_status; + + u32 spi_clk; + u32 status; + + bool xfer_failed; + bool keep_cs; + bool cs_active; +}; + +struct at91_usart_spi_device { + struct gpio_desc *npcs_pin; + u32 mr; +}; + +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 = 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 (tx_buf && remaining) { + if (at91_usart_spi_tx_ready(aus)) + spi_writel(aus, THR, tx_buf[len - remaining]); + aus->current_tx_remaining_bytes--; + } else { + if (at91_usart_spi_tx_ready(aus)) + spi_writel(aus, THR, US_DUMMY_TX); + } +} + +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 (aus->current_rx_remaining_bytes) { + rx_buf[len - remaining] = spi_readb(aus, RHR); + aus->current_rx_remaining_bytes--; + } else { + spi_readb(aus, RHR); + } +} + +static inline void at91_usart_spi_cs_activate(struct spi_device *spi) +{ + struct at91_usart_spi_device *ausd = spi->controller_state; + struct at91_usart_spi *aus = spi_master_get_devdata(spi->controller); + u32 active = spi->mode & SPI_CS_HIGH; + + gpiod_set_value(ausd->npcs_pin, active); + aus->cs_active = true; +} + +static inline void at91_usart_spi_cs_deactivate(struct spi_device *spi) +{ + struct at91_usart_spi_device *ausd = spi->controller_state; + struct at91_usart_spi *aus = spi_master_get_devdata(spi->controller); + u32 active = spi->mode & SPI_CS_HIGH; + + gpiod_set_value(ausd->npcs_pin, !active); + aus->cs_active = false; +} + +static inline void at91_usart_spi_set_mode_register(struct spi_device *spi) +{ + struct at91_usart_spi_device *ausd = spi->controller_state; + struct at91_usart_spi *aus = spi_master_get_devdata(spi->controller); + + spi_writel(aus, MR, ausd->mr); +} + +static inline void +at91_usart_spi_enable_irq_and_hw(struct at91_usart_spi *aus) +{ + spi_writel(aus, CR, US_CR_RXEN | US_CR_TXEN); + spi_writel(aus, IER, US_IR_OVRE | US_IR_RXRDY); +} + +static inline void +at91_usart_spi_disable_irq_and_hw(struct at91_usart_spi *aus) +{ + spi_writel(aus, CR, US_CR_RXDIS | US_CR_TXDIS | + US_CR_RSTRX | US_CR_RSTTX); + spi_writel(aus, IDR, US_IR_OVRE | US_IR_RXRDY); +} + +static inline void +at91_usart_spi_set_xfer_speed(struct at91_usart_spi *aus, + struct spi_transfer *xfer) +{ + 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; + aus->done_status = -EIO; + 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); + struct at91_usart_spi_device *ausd = spi->controller_state; + struct gpio_desc *npcs_pin; + unsigned int mr = spi_readl(aus, MR); + u8 bits = spi->bits_per_word; + + if (bits != 8) { + dev_dbg(&spi->dev, "Only 8 bits per word are supported\n"); + return -EINVAL; + } + + 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) { + if (gpio_is_valid(spi->cs_gpio)) { + npcs_pin = gpio_to_desc(spi->cs_gpio); + } else { + dev_dbg(&spi->dev, "Invalid chip select\n"); + return -EINVAL; + } + + ausd = kzalloc(sizeof(*ausd), GFP_KERNEL); + if (!ausd) + return -ENOMEM; + gpiod_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH)); + + ausd->npcs_pin = npcs_pin; + spi->controller_state = ausd; + } + + ausd->mr = mr; + + dev_dbg(&spi->dev, + "setup: bpw %u mode 0x%x -> mr %d %08x\n", + bits, spi->mode, spi->chip_select, mr); + + return 0; +} + +static int at91_usart_spi_one_transfer(struct spi_controller *controller, + struct spi_message *msg, + struct spi_transfer *xfer) +{ + struct at91_usart_spi *aus = spi_master_get_devdata(controller); + struct spi_device *spi = msg->spi; + const u8 *tx_buf = xfer->tx_buf; + u8 *rx_buf = xfer->rx_buf; + + if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) { + dev_dbg(&spi->dev, "missing rx and tx buf\n"); + return -EINVAL; + } + + at91_usart_spi_set_xfer_speed(aus, xfer); + aus->done_status = 0; + aus->xfer_failed = false; + aus->current_transfer = xfer; + aus->current_tx_remaining_bytes = xfer->len; + aus->current_rx_remaining_bytes = xfer->len; + if (!tx_buf) + aus->current_tx_remaining_bytes = 0; + if (!rx_buf) + aus->current_rx_remaining_bytes = 0; + + while ((aus->current_tx_remaining_bytes || + aus->current_rx_remaining_bytes) && !aus->xfer_failed) { + 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; + } + + if (xfer->delay_usecs) + udelay(xfer->delay_usecs); + + if (xfer->cs_change) { + if (list_is_last(&xfer->transfer_list, &msg->transfers)) { + aus->keep_cs = true; + } else { + aus->cs_active = !aus->cs_active; + if (aus->cs_active) + at91_usart_spi_cs_activate(spi); + else + at91_usart_spi_cs_deactivate(spi); + } + } + + return 0; +} + +static int +at91_usart_spi_transfer_one_message(struct spi_controller *controller, + struct spi_message *msg) +{ + struct at91_usart_spi *aus = spi_master_get_devdata(controller); + struct spi_transfer *xfer; + struct spi_device *spi = msg->spi; + int ret; + + dev_dbg(&spi->dev, "new message %p submitted for %s\n", + msg, dev_name(&spi->dev)); + at91_usart_spi_enable_irq_and_hw(aus); + at91_usart_spi_set_mode_register(spi); + at91_usart_spi_cs_activate(spi); + + aus->keep_cs = false; + + msg->status = 0; + msg->actual_length = 0; + + list_for_each_entry(xfer, &msg->transfers, transfer_list) { + ret = at91_usart_spi_one_transfer(controller, msg, xfer); + if (ret) + goto msg_done; + } + +msg_done: + + if (!aus->keep_cs) + at91_usart_spi_cs_deactivate(spi); + + at91_usart_spi_disable_irq_and_hw(aus); + + msg->status = aus->done_status; + spi_finalize_current_message(spi->master); + + return ret; +} + +static void at91_usart_spi_cleanup(struct spi_device *spi) +{ + struct at91_usart_spi_device *ausd = spi->controller_state; + + if (!ausd) + return; + + spi->controller_state = NULL; + kfree(ausd); +} + +static int at91_usart_spi_gpio_cs(struct platform_device *pdev) +{ + struct spi_controller *controller = platform_get_drvdata(pdev); + struct device_node *np = controller->dev.parent->of_node; + struct gpio_desc *cs_gpio; + int nb; + int i; + + if (!np) + return 0; + + nb = of_gpio_named_count(np, "cs-gpios"); + for (i = 0; i < nb; i++) { + cs_gpio = devm_gpiod_get_from_of_node(&pdev->dev, + pdev->dev.parent->of_node, + "cs-gpios", + i, GPIOD_OUT_HIGH, + dev_name(&pdev->dev)); + if (IS_ERR(cs_gpio)) + return PTR_ERR(cs_gpio); + } + + controller->num_chipselect = nb; + + return 0; +} + +static void at91_usart_spi_init(struct at91_usart_spi *aus) +{ + spi_writel(aus, MR, US_MR_SPI_MASTER | US_MR_CHRL | US_MR_CLKO | + US_MR_WRDBT); + spi_writel(aus, CR, US_CR_RXDIS | US_CR_TXDIS | US_CR_RSTRX | + US_CR_RSTTX); +} + +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 -ENXIO; + + 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; + + 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->num_chipselect = 0; + controller->setup = at91_usart_spi_setup; + controller->flags = SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX; + controller->transfer_one_message = at91_usart_spi_transfer_one_message; + 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 = at91_usart_spi_gpio_cs(pdev); + if (ret) + goto at91_usart_spi_probe_fail; + + 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); + + spin_lock_init(&aus->lock); + ret = devm_spi_register_master(&pdev->dev, controller); + if (ret) + goto fail_register_master; + + dev_info(&pdev->dev, + "Atmel USART SPI Controller version 0x%x at 0x%08lx (irq %d)\n", + spi_readl(aus, VERSION), + (unsigned long)regs->start, irq); + + return 0; + +fail_register_master: + clk_disable_unprepare(clk); +at91_usart_spi_probe_fail: + spi_master_put(controller); + return ret; +} + +static int at91_usart_spi_remove(struct platform_device *pdev) +{ + struct spi_master *master = platform_get_drvdata(pdev); + struct at91_usart_spi *aus = spi_master_get_devdata(master); + + clk_disable_unprepare(aus->clk); + + return 0; +} + +static const struct of_device_id at91_usart_spi_dt_ids[] = { + { .compatible = "microchip,sama5d3-usart-spi"}, + { .compatible = "microchip,sama5d4-usart-spi"}, + { .compatible = "microchip,at91sam9g45-usart-spi"}, + { /* sentinel */} +}; + +MODULE_DEVICE_TABLE(of, at91_usart_spi_dt_ids); + +static struct platform_driver at91_usart_spi_driver = { + .driver = { + .name = "at91_usart_spi", + .of_match_table = of_match_ptr(at91_usart_spi_dt_ids), + }, + .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 "); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:at91_usart_spi");