Immutable branch between MFD, SPI and TTY due for the v4.20 merge window

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2024-12-23 22:21:59 +07:00 · 2018-09-10 18:00:43 +02:00 · 2018-09-10 18:00:43 +02:00 · 77792652d6
commit 77792652d6
parent 11da3a7f84 c24d25317a
11 changed files with 606 additions and 17 deletions
--- a/Documentation/devicetree/bindings/serial/atmel-usart.txt
+++ b/Documentation/devicetree/bindings/serial/atmel-usart.txt
@ -1,6 +1,6 @@
 * Atmel Universal Synchronous Asynchronous Receiver/Transmitter (USART)

-Required properties:
+Required properties for USART:
 - compatible: Should be "atmel,<chip>-usart" or "atmel,<chip>-dbgu"
  The compatible <chip> indicated will be the first SoC to support an
  additional mode or an USART new feature.
@ -11,7 +11,13 @@ Required properties:
 	Required elements: "usart"
 - clocks: phandles to input clocks.

-Optional properties:
+Required properties for USART in SPI mode:
+- #size-cells      : Must be <0>
+- #address-cells   : Must be <1>
+- cs-gpios: chipselects (internal cs not supported)
+- atmel,usart-mode : Must be <AT91_USART_MODE_SPI> (found in dt-bindings/mfd/at91-usart.h)
+
+Optional properties in serial mode:
 - atmel,use-dma-rx: use of PDC or DMA for receiving data
 - atmel,use-dma-tx: use of PDC or DMA for transmitting data
 - {rts,cts,dtr,dsr,rng,dcd}-gpios: specify a GPIO for RTS/CTS/DTR/DSR/RI/DCD line respectively.
@ -62,3 +68,18 @@ Example:
 		dma-names = "tx", "rx";
 		atmel,fifo-size = <32>;
 	};
+
+- SPI mode:
+	#include <dt-bindings/mfd/at91-usart.h>
+
+	spi0: spi@f001c000 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "atmel,at91rm9200-usart", "atmel,at91sam9260-usart";
+		atmel,usart-mode = <AT91_USART_MODE_SPI>;
+		reg = <0xf001c000 0x100>;
+		interrupts = <12 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&usart0_clk>;
+		clock-names = "usart";
+		cs-gpios = <&pioB 3 0>;
+	};
--- a/16
+++ b/16
@ -9503,6 +9503,7 @@ M:	Richard Genoud <richard.genoud@gmail.com>
 S:	Maintained
 F:	drivers/tty/serial/atmel_serial.c
 F:	drivers/tty/serial/atmel_serial.h
+F:	Documentation/devicetree/bindings/mfd/atmel-usart.txt

 MICROCHIP / ATMEL DMA DRIVER
 M:	Ludovic Desroches <ludovic.desroches@microchip.com>
@ -9534,6 +9535,21 @@ S:	Supported
 F:	drivers/mtd/nand/raw/atmel/*
 F:	Documentation/devicetree/bindings/mtd/atmel-nand.txt

+MICROCHIP AT91 USART MFD DRIVER
+M:	Radu Pirea <radu.pirea@microchip.com>
+L:	linux-kernel@vger.kernel.org
+S:	Supported
+F:	drivers/mfd/at91-usart.c
+F:	include/dt-bindings/mfd/at91-usart.h
+F:	Documentation/devicetree/bindings/mfd/atmel-usart.txt
+
+MICROCHIP AT91 USART SPI DRIVER
+M:	Radu Pirea <radu.pirea@microchip.com>
+L:	linux-spi@vger.kernel.org
+S:	Supported
+F:	drivers/spi/spi-at91-usart.c
+F:	Documentation/devicetree/bindings/mfd/atmel-usart.txt
+
 MICROCHIP KSZ SERIES ETHERNET SWITCH DRIVER
 M:	Woojung Huh <Woojung.Huh@microchip.com>
 M:	Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@ -99,6 +99,15 @@ config MFD_AAT2870_CORE
 	  additional drivers must be enabled in order to use the
 	  functionality of the device.

+config MFD_AT91_USART
+	tristate "AT91 USART Driver"
+	select MFD_CORE
+	help
+	  Select this to get support for AT91 USART IP. This is a wrapper
+	  over at91-usart-serial driver and usart-spi-driver. Only one function
+	  can be used at a time. The choice is done at boot time by the probe
+	  function of this MFD driver according to a device tree property.
+
 config MFD_ATMEL_FLEXCOM
 	tristate "Atmel Flexcom (Flexible Serial Communication Unit)"
 	select MFD_CORE
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@ -196,6 +196,7 @@ obj-$(CONFIG_MFD_SPMI_PMIC)	+= qcom-spmi-pmic.o
 obj-$(CONFIG_TPS65911_COMPARATOR)	+= tps65911-comparator.o
 obj-$(CONFIG_MFD_TPS65090)	+= tps65090.o
 obj-$(CONFIG_MFD_AAT2870_CORE)	+= aat2870-core.o
+obj-$(CONFIG_MFD_AT91_USART)	+= at91-usart.o
 obj-$(CONFIG_MFD_ATMEL_FLEXCOM)	+= atmel-flexcom.o
 obj-$(CONFIG_MFD_ATMEL_HLCDC)	+= atmel-hlcdc.o
 obj-$(CONFIG_MFD_ATMEL_SMC)	+= atmel-smc.o
--- a/drivers/mfd/at91-usart.c
+++ b/drivers/mfd/at91-usart.c
@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for AT91 USART
+ *
+ * Copyright (C) 2018 Microchip Technology
+ *
+ * Author: Radu Pirea <radu.pirea@microchip.com>
+ *
+ */
+
+#include <dt-bindings/mfd/at91-usart.h>
+
+#include <linux/module.h>
+#include <linux/mfd/core.h>
+#include <linux/property.h>
+
+static struct mfd_cell at91_usart_spi_subdev = {
+		.name = "at91_usart_spi",
+		.of_compatible = "microchip,at91sam9g45-usart-spi",
+	};
+
+static struct mfd_cell at91_usart_serial_subdev = {
+		.name = "atmel_usart_serial",
+		.of_compatible = "atmel,at91rm9200-usart-serial",
+	};
+
+static int at91_usart_mode_probe(struct platform_device *pdev)
+{
+	struct mfd_cell cell;
+	u32 opmode = AT91_USART_MODE_SERIAL;
+
+	device_property_read_u32(&pdev->dev, "atmel,usart-mode", &opmode);
+
+	switch (opmode) {
+	case AT91_USART_MODE_SPI:
+		cell = at91_usart_spi_subdev;
+		break;
+	case AT91_USART_MODE_SERIAL:
+		cell = at91_usart_serial_subdev;
+		break;
+	default:
+		dev_err(&pdev->dev, "atmel,usart-mode has an invalid value %u\n",
+			opmode);
+		return -EINVAL;
+	}
+
+	return devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO, &cell, 1,
+			      NULL, 0, NULL);
+}
+
+static const struct of_device_id at91_usart_mode_of_match[] = {
+	{ .compatible = "atmel,at91rm9200-usart" },
+	{ .compatible = "atmel,at91sam9260-usart" },
+	{ /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, at91_usart_mode_of_match);
+
+static struct platform_driver at91_usart_mfd = {
+	.probe	= at91_usart_mode_probe,
+	.driver	= {
+		.name		= "at91_usart_mode",
+		.of_match_table	= at91_usart_mode_of_match,
+	},
+};
+
+module_platform_driver(at91_usart_mfd);
+
+MODULE_AUTHOR("Radu Pirea <radu.pirea@microchip.com>");
+MODULE_DESCRIPTION("AT91 USART MFD driver");
+MODULE_LICENSE("GPL v2");
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@ -83,6 +83,14 @@ 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 SPI driver"
+	depends on (ARCH_AT91 || COMPILE_TEST)
+	depends on 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
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@ -16,6 +16,7 @@ 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
--- a/drivers/spi/spi-at91-usart.c
+++ b/drivers/spi/spi-at91-usart.c
@ -0,0 +1,432 @@
+// 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/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_gpio.h>
+#include <linux/platform_device.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)
+
+/* 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 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;
+
+	u32			spi_clk;
+	u32			status;
+
+	bool			xfer_failed;
+};
+
+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);
+	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) {
+		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",
+		bits, spi->mode, spi->chip_select, mr);
+
+	return 0;
+}
+
+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);
+
+	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) {
+		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;
+}
+
+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;
+}
+
+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 device_node *np = pdev->dev.parent->of_node;
+	int i;
+	int ret;
+	int nb;
+
+	if (!np)
+		return -EINVAL;
+
+	nb = of_gpio_named_count(np, "cs-gpios");
+	for (i = 0; i < nb; i++) {
+		int cs_gpio = of_get_named_gpio(np, "cs-gpios", i);
+
+		if (cs_gpio < 0)
+			return cs_gpio;
+
+		if (gpio_is_valid(cs_gpio)) {
+			ret = devm_gpio_request_one(&pdev->dev, cs_gpio,
+						    GPIOF_DIR_OUT,
+						    dev_name(&pdev->dev));
+			if (ret)
+				return ret;
+		}
+	}
+
+	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->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);
+
+	spin_lock_init(&aus->lock);
+	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:
+	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_controller *ctlr = platform_get_drvdata(pdev);
+	struct at91_usart_spi *aus = spi_master_get_devdata(ctlr);
+
+	clk_disable_unprepare(aus->clk);
+
+	return 0;
+}
+
+static const struct of_device_id at91_usart_spi_dt_ids[] = {
+	{ .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",
+	},
+	.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");
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@ -118,6 +118,7 @@ config SERIAL_ATMEL
 	depends on ARCH_AT91 || COMPILE_TEST
 	select SERIAL_CORE
 	select SERIAL_MCTRL_GPIO if GPIOLIB
+	select MFD_AT91_USART
 	help
 	  This enables the driver for the on-chip UARTs of the Atmel
 	  AT91 processors.
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@ -193,8 +193,7 @@ static struct console atmel_console;

 #if defined(CONFIG_OF)
 static const struct of_device_id atmel_serial_dt_ids[] = {
-	{ .compatible = "atmel,at91rm9200-usart" },
-	{ .compatible = "atmel,at91sam9260-usart" },
+	{ .compatible = "atmel,at91rm9200-usart-serial" },
 	{ /* sentinel */ }
 };
 #endif
@ -915,6 +914,7 @@ static void atmel_tx_dma(struct uart_port *port)
 static int atmel_prepare_tx_dma(struct uart_port *port)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	struct device *mfd_dev = port->dev->parent;
 	dma_cap_mask_t		mask;
 	struct dma_slave_config config;
 	int ret, nent;
@ -922,7 +922,7 @@ static int atmel_prepare_tx_dma(struct uart_port *port)
 	dma_cap_zero(mask);
 	dma_cap_set(DMA_SLAVE, mask);

-	atmel_port->chan_tx = dma_request_slave_channel(port->dev, "tx");
+	atmel_port->chan_tx = dma_request_slave_channel(mfd_dev, "tx");
 	if (atmel_port->chan_tx == NULL)
 		goto chan_err;
 	dev_info(port->dev, "using %s for tx DMA transfers\n",
@ -1093,6 +1093,7 @@ static void atmel_rx_from_dma(struct uart_port *port)
 static int atmel_prepare_rx_dma(struct uart_port *port)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	struct device *mfd_dev = port->dev->parent;
 	struct dma_async_tx_descriptor *desc;
 	dma_cap_mask_t		mask;
 	struct dma_slave_config config;
@ -1104,7 +1105,7 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
 	dma_cap_zero(mask);
 	dma_cap_set(DMA_CYCLIC, mask);

-	atmel_port->chan_rx = dma_request_slave_channel(port->dev, "rx");
+	atmel_port->chan_rx = dma_request_slave_channel(mfd_dev, "rx");
 	if (atmel_port->chan_rx == NULL)
 		goto chan_err;
 	dev_info(port->dev, "using %s for rx DMA transfers\n",
@ -2222,8 +2223,8 @@ static const char *atmel_type(struct uart_port *port)
 */
 static void atmel_release_port(struct uart_port *port)
 {
-	struct platform_device *pdev = to_platform_device(port->dev);
-	int size = pdev->resource[0].end - pdev->resource[0].start + 1;
+	struct platform_device *mpdev = to_platform_device(port->dev->parent);
+	int size = resource_size(mpdev->resource);

 	release_mem_region(port->mapbase, size);

@ -2238,8 +2239,8 @@ static void atmel_release_port(struct uart_port *port)
 */
 static int atmel_request_port(struct uart_port *port)
 {
-	struct platform_device *pdev = to_platform_device(port->dev);
-	int size = pdev->resource[0].end - pdev->resource[0].start + 1;
+	struct platform_device *mpdev = to_platform_device(port->dev->parent);
+	int size = resource_size(mpdev->resource);

 	if (!request_mem_region(port->mapbase, size, "atmel_serial"))
 		return -EBUSY;
@ -2341,27 +2342,28 @@ static int atmel_init_port(struct atmel_uart_port *atmel_port,
 {
 	int ret;
 	struct uart_port *port = &atmel_port->uart;
+	struct platform_device *mpdev = to_platform_device(pdev->dev.parent);

 	atmel_init_property(atmel_port, pdev);
 	atmel_set_ops(port);

-	uart_get_rs485_mode(&pdev->dev, &port->rs485);
+	uart_get_rs485_mode(&mpdev->dev, &port->rs485);

 	port->iotype		= UPIO_MEM;
 	port->flags		= UPF_BOOT_AUTOCONF | UPF_IOREMAP;
 	port->ops		= &atmel_pops;
 	port->fifosize		= 1;
 	port->dev		= &pdev->dev;
-	port->mapbase	= pdev->resource[0].start;
-	port->irq	= pdev->resource[1].start;
+	port->mapbase		= mpdev->resource[0].start;
+	port->irq		= mpdev->resource[1].start;
 	port->rs485_config	= atmel_config_rs485;
-	port->membase	= NULL;
+	port->membase		= NULL;

 	memset(&atmel_port->rx_ring, 0, sizeof(atmel_port->rx_ring));

 	/* for console, the clock could already be configured */
 	if (!atmel_port->clk) {
-		atmel_port->clk = clk_get(&pdev->dev, "usart");
+		atmel_port->clk = clk_get(&mpdev->dev, "usart");
 		if (IS_ERR(atmel_port->clk)) {
 			ret = PTR_ERR(atmel_port->clk);
 			atmel_port->clk = NULL;
@ -2694,13 +2696,22 @@ static void atmel_serial_probe_fifos(struct atmel_uart_port *atmel_port,
 static int atmel_serial_probe(struct platform_device *pdev)
 {
 	struct atmel_uart_port *atmel_port;
-	struct device_node *np = pdev->dev.of_node;
+	struct device_node *np = pdev->dev.parent->of_node;
 	void *data;
 	int ret = -ENODEV;
 	bool rs485_enabled;

 	BUILD_BUG_ON(ATMEL_SERIAL_RINGSIZE & (ATMEL_SERIAL_RINGSIZE - 1));

+	/*
+	 * In device tree there is no node with "atmel,at91rm9200-usart-serial"
+	 * as compatible string. This driver is probed by at91-usart mfd driver
+	 * which is just a wrapper over the atmel_serial driver and
+	 * spi-at91-usart driver. All attributes needed by this driver are
+	 * found in of_node of parent.
+	 */
+	pdev->dev.of_node = np;
+
 	ret = of_alias_get_id(np, "serial");
 	if (ret < 0)
 		/* port id not found in platform data nor device-tree aliases:
@ -2836,6 +2847,7 @@ static int atmel_serial_remove(struct platform_device *pdev)

 	clk_put(atmel_port->clk);
 	atmel_port->clk = NULL;
+	pdev->dev.of_node = NULL;

 	return ret;
 }
@ -2846,7 +2858,7 @@ static struct platform_driver atmel_serial_driver = {
 	.suspend	= atmel_serial_suspend,
 	.resume		= atmel_serial_resume,
 	.driver		= {
-		.name			= "atmel_usart",
+		.name			= "atmel_usart_serial",
 		.of_match_table		= of_match_ptr(atmel_serial_dt_ids),
 	},
 };
--- a/include/dt-bindings/mfd/at91-usart.h
+++ b/include/dt-bindings/mfd/at91-usart.h
@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * This header provides macros for AT91 USART DT bindings.
+ *
+ * Copyright (C) 2018 Microchip Technology
+ *
+ * Author: Radu Pirea <radu.pirea@microchip.com>
+ *
+ */
+
+#ifndef __DT_BINDINGS_AT91_USART_H__
+#define __DT_BINDINGS_AT91_USART_H__
+
+#define AT91_USART_MODE_SERIAL	0
+#define AT91_USART_MODE_SPI	1
+
+#endif /* __DT_BINDINGS_AT91_USART_H__ */