[PATCH v2 0/6] Driver for at91 usart in spi mode

[PATCH v2 0/6] Driver for at91 usart in spi mode

[Radu Pirea]

Hello,

This is the second version of driver. I added a mfd driver which by
default probes atmel_serial driver and if in dt is specified to probe
the spi driver, then the spi-at91-usart driver will be probed. The
compatible for atmel_serial is now the compatible for at91-usart mfd
driver and compatilbe for atmel_serial driver was changed in order to
keep the bindings for serial as they are.

Changes in v1:
- added spi-at91-usart driver

Changes in v2:
- added at91-usart mfd driver
- modified spi-at91-usart driver to work as mfd driver child
- modified atmel_serial driver to work as mfd driver child

Radu Pirea (6):
  MAINTAINERS: add at91 usart mfd driver
  mfd: at91-usart: added mfd driver for usart
  MAINTAINERS: add at91 usart spi driver
  dt-bindings: add binding for at91-usart in spi mode
  spi: at91-usart: add driver for at91-usart as spi
  tty/serial: atmel: changed the driver to work under at91-usart mfd

 .../bindings/spi/microchip,at91-usart-spi.txt |  28 +
 MAINTAINERS                                   |  14 +
 drivers/mfd/Kconfig                           |  10 +
 drivers/mfd/Makefile                          |   1 +
 drivers/mfd/at91-usart.c                      |  81 +++
 drivers/spi/Kconfig                           |   9 +
 drivers/spi/Makefile                          |   1 +
 drivers/spi/spi-at91-usart.c                  | 545 ++++++++++++++++++
 drivers/tty/serial/Kconfig                    |   1 +
 drivers/tty/serial/atmel_serial.c             |  29 +-
 include/dt-bindings/mfd/at91-usart.h          |  17 +
 11 files changed, 722 insertions(+), 14 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/spi/microchip,at91-usart-spi.txt
 create mode 100644 drivers/mfd/at91-usart.c
 create mode 100644 drivers/spi/spi-at91-usart.c
 create mode 100644 include/dt-bindings/mfd/at91-usart.h

-- 
2.17.0

[PATCH v2 1/6] MAINTAINERS: add at91 usart mfd driver

[Radu Pirea]

Added entry for at91 usart mfd driver.

Signed-off-by: Radu Pirea <radu.pirea@microchip.com>
---
 MAINTAINERS | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 8e2a2fddbd19..ca06c6f58299 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9192,6 +9192,13 @@ 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
+
 MICROCHIP KSZ SERIES ETHERNET SWITCH DRIVER
 M:	Woojung Huh <Woojung.Huh@microchip.com>
 M:	Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>
-- 
2.17.0

[PATCH v2 2/6] mfd: at91-usart: added mfd driver for usart

[Radu Pirea]

This mfd driver is just a wrapper over atmel_serial driver and
spi-at91-usart driver. Selection of one of the drivers is based on a
property from device tree. If the property is not specified, the default
driver is atmel_serial.

Signed-off-by: Radu Pirea <radu.pirea@microchip.com>
---
 drivers/mfd/Kconfig                  | 10 ++++
 drivers/mfd/Makefile                 |  1 +
 drivers/mfd/at91-usart.c             | 81 ++++++++++++++++++++++++++++
 include/dt-bindings/mfd/at91-usart.h | 17 ++++++
 4 files changed, 109 insertions(+)
 create mode 100644 drivers/mfd/at91-usart.c
 create mode 100644 include/dt-bindings/mfd/at91-usart.h

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index b860eb5aa194..de99b79061b7 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -99,6 +99,16 @@ 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
+	depends on OF
+	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
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index d9d2cf0d32ef..db1332aa96db 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -185,6 +185,7 @@ 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
diff --git a/drivers/mfd/at91-usart.c b/drivers/mfd/at91-usart.c
new file mode 100644
index 000000000000..cd8f020ca7c0
--- /dev/null
+++ b/drivers/mfd/at91-usart.c
@@ -0,0 +1,81 @@
+// 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/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mfd/core.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.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 device_node *np = pdev->dev.of_node;
+	struct mfd_cell cell;
+	u32 opmode;
+	int err;
+
+	err = of_property_read_u32(np, "at91,usart-mode", &opmode);
+
+	switch (opmode) {
+	case AT91_USART_MODE_SPI:
+		cell = at91_usart_spi_subdev;
+		break;
+	case AT91_USART_MODE_SERIAL:
+	default:
+		cell = at91_usart_serial_subdev;
+	}
+
+	err = mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO, &cell, 1,
+			      NULL, 0, NULL);
+	if (err) {
+		dev_err(&pdev->dev, "failed to add subdevices\n");
+		return err;
+	}
+
+	return devm_of_platform_populate(&pdev->dev);
+}
+
+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_flexcom_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");
diff --git a/include/dt-bindings/mfd/at91-usart.h b/include/dt-bindings/mfd/at91-usart.h
new file mode 100644
index 000000000000..ac811628a42d
--- /dev/null
+++ 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	1
+#define AT91_USART_MODE_SPI	2
+
+#endif /* __DT_BINDINGS_AT91_USART_H__ */
-- 
2.17.0

[PATCH v2 3/6] MAINTAINERS: add at91 usart spi driver

[Radu Pirea]

Added entry for at91 usart mfd driver.

Signed-off-by: Radu Pirea <radu.pirea@microchip.com>
---
 MAINTAINERS | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index ca06c6f58299..9243b9007966 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9199,6 +9199,13 @@ S:	Supported
 F:	drivers/mfd/at91-usart.c
 F:	include/dt-bindings/mfd/at91-usart.h
 
+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/spi/microchip,at91-usart-spi.txt
+
 MICROCHIP KSZ SERIES ETHERNET SWITCH DRIVER
 M:	Woojung Huh <Woojung.Huh@microchip.com>
 M:	Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>
-- 
2.17.0

[PATCH v2 4/6] dt-bindings: add binding for at91-usart in spi mode

[Radu Pirea]

These are bindings for at91-usart IP in spi spi mode. There is no support for
internal chip select. Only kind of chip selects available are gpio chip
selects.

Signed-off-by: Radu Pirea <radu.pirea@microchip.com>
---
 .../bindings/spi/microchip,at91-usart-spi.txt | 28 +++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/spi/microchip,at91-usart-spi.txt

diff --git a/Documentation/devicetree/bindings/spi/microchip,at91-usart-spi.txt b/Documentation/devicetree/bindings/spi/microchip,at91-usart-spi.txt
new file mode 100644
index 000000000000..b68a3bec4121
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/microchip,at91-usart-spi.txt
@@ -0,0 +1,28 @@
+* Universal Synchronous Asynchronous Receiver/Transmitter (USART) in SPI mode
+
+Required properties:
+- #size-cells      : Must be <0>
+- #address-cells   : Must be <1>
+- compatible: Should be "atmel,at91rm9200-usart" or "atmel,at91sam9260-usart"
+- reg: Should contain registers location and length
+- interrupts: Should contain interrupt
+- clocks: phandles to input clocks.
+- clock-names: tuple listing input clock names.
+	Required elements: "usart"
+- cs-gpios: chipselects (internal cs not supported)
+- at91,usart-mode: AT91_USART_MODE_SPI (found in dt-bindings/mfd/at91-usart.h)
+
+Example:
+	#include <dt-bindings/mfd/at91-usart.h>
+
+	spi0: spi@f001c000 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "atmel,at91rm9200-usart", "atmel,at91sam9260-usart";
+		at91,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>;
+	};
-- 
2.17.0

[PATCH v2 5/6] spi: at91-usart: add driver for at91-usart as spi

[Radu Pirea]

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 <radu.pirea@microchip.com>
---
 drivers/spi/Kconfig          |   9 +
 drivers/spi/Makefile         |   1 +
 drivers/spi/spi-at91-usart.c | 545 +++++++++++++++++++++++++++++++++++
 3 files changed, 555 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..94b3eb6e7296
--- /dev/null
+++ b/drivers/spi/spi-at91-usart.c
@@ -0,0 +1,545 @@
+// 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/err.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+
+#include <linux/pinctrl/consumer.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_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->bus_num = PLATFORM_DEVID_AUTO;
+	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 <radu.pirea@microchip.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:at91_usart_spi");
-- 
2.17.0

[PATCH v2 6/6] tty/serial: atmel: changed the driver to work under at91-usart mfd

[Radu Pirea]

This patch modifies the place where resources and device tree properties
are searched.

Signed-off-by: Radu Pirea <radu.pirea@microchip.com>
---
 drivers/tty/serial/Kconfig        |  1 +
 drivers/tty/serial/atmel_serial.c | 29 +++++++++++++++--------------
 2 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 3682fd3e960c..25e55332f8b1 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -119,6 +119,7 @@ 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.
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index df46a9e88c34..6b4494352853 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -193,8 +193,8 @@ 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" },
+	{ .compatible = "atmel,at91sam9260-usart-serial" },
 	{ /* sentinel */ }
 };
 #endif
@@ -1631,7 +1631,7 @@ static void atmel_tasklet_tx_func(unsigned long data)
 static void atmel_init_property(struct atmel_uart_port *atmel_port,
 				struct platform_device *pdev)
 {
-	struct device_node *np = pdev->dev.of_node;
+	struct device_node *np = pdev->dev.parent->of_node;
 
 	/* DMA/PDC usage specification */
 	if (of_property_read_bool(np, "atmel,use-dma-rx")) {
@@ -2223,7 +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;
+	int size = to_platform_device(pdev->dev.parent)->resource[0].end -
+		to_platform_device(pdev->dev.parent)->resource[0].start + 1;
 
 	release_mem_region(port->mapbase, size);
 
@@ -2239,7 +2240,8 @@ 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;
+	int size = to_platform_device(pdev->dev.parent)->resource[0].end -
+		to_platform_device(pdev->dev.parent)->resource[0].start + 1;
 
 	if (!request_mem_region(port->mapbase, size, "atmel_serial"))
 		return -EBUSY;
@@ -2345,23 +2347,23 @@ static int atmel_init_port(struct atmel_uart_port *atmel_port,
 	atmel_init_property(atmel_port, pdev);
 	atmel_set_ops(port);
 
-	uart_get_rs485_mode(&pdev->dev, &port->rs485);
+	uart_get_rs485_mode(pdev->dev.parent, &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		= to_platform_device(pdev->dev.parent)->resource[0].start;
+	port->irq		= to_platform_device(pdev->dev.parent)->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(pdev->dev.parent, "usart");
 		if (IS_ERR(atmel_port->clk)) {
 			ret = PTR_ERR(atmel_port->clk);
 			atmel_port->clk = NULL;
@@ -2656,7 +2658,7 @@ static void atmel_serial_probe_fifos(struct atmel_uart_port *atmel_port,
 	atmel_port->rts_low = 0;
 	atmel_port->rts_high = 0;
 
-	if (of_property_read_u32(pdev->dev.of_node,
+	if (of_property_read_u32(pdev->dev.parent->of_node,
 				 "atmel,fifo-size",
 				 &atmel_port->fifo_size))
 		return;
@@ -2694,11 +2696,10 @@ 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));
 
 	ret = of_alias_get_id(np, "serial");
@@ -2845,7 +2846,7 @@ 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),
 	},
 };
-- 
2.17.0

Re: [PATCH v2 0/6] Driver for at91 usart in spi mode

[Lee Jones]

On Fri, 04 May 2018, Radu Pirea wrote:

> Hello,
> 
> This is the second version of driver. I added a mfd driver which by
> default probes atmel_serial driver and if in dt is specified to probe
> the spi driver, then the spi-at91-usart driver will be probed. The
> compatible for atmel_serial is now the compatible for at91-usart mfd
> driver and compatilbe for atmel_serial driver was changed in order to
> keep the bindings for serial as they are.
> 
> Changes in v1:
> - added spi-at91-usart driver
> 
> Changes in v2:
> - added at91-usart mfd driver
> - modified spi-at91-usart driver to work as mfd driver child
> - modified atmel_serial driver to work as mfd driver child
> 
> Radu Pirea (6):
>   MAINTAINERS: add at91 usart mfd driver
>   mfd: at91-usart: added mfd driver for usart
>   MAINTAINERS: add at91 usart spi driver
>   dt-bindings: add binding for at91-usart in spi mode
>   spi: at91-usart: add driver for at91-usart as spi
>   tty/serial: atmel: changed the driver to work under at91-usart mfd
> 
>  .../bindings/spi/microchip,at91-usart-spi.txt |  28 +
>  MAINTAINERS                                   |  14 +
>  drivers/mfd/Kconfig                           |  10 +
>  drivers/mfd/Makefile                          |   1 +
>  drivers/mfd/at91-usart.c                      |  81 +++
>  drivers/spi/Kconfig                           |   9 +
>  drivers/spi/Makefile                          |   1 +
>  drivers/spi/spi-at91-usart.c                  | 545 ++++++++++++++++++
>  drivers/tty/serial/Kconfig                    |   1 +
>  drivers/tty/serial/atmel_serial.c             |  29 +-
>  include/dt-bindings/mfd/at91-usart.h          |  17 +
>  11 files changed, 722 insertions(+), 14 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/spi/microchip,at91-usart-spi.txt
>  create mode 100644 drivers/mfd/at91-usart.c
>  create mode 100644 drivers/spi/spi-at91-usart.c
>  create mode 100644 include/dt-bindings/mfd/at91-usart.h

Applied, thanks.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v2 0/6] Driver for at91 usart in spi mode

[Lee Jones]

On Tue, 29 May 2018, Lee Jones wrote:

> On Fri, 04 May 2018, Radu Pirea wrote:
> 
> > Hello,
> > 
> > This is the second version of driver. I added a mfd driver which by
> > default probes atmel_serial driver and if in dt is specified to probe
> > the spi driver, then the spi-at91-usart driver will be probed. The
> > compatible for atmel_serial is now the compatible for at91-usart mfd
> > driver and compatilbe for atmel_serial driver was changed in order to
> > keep the bindings for serial as they are.
> > 
> > Changes in v1:
> > - added spi-at91-usart driver
> > 
> > Changes in v2:
> > - added at91-usart mfd driver
> > - modified spi-at91-usart driver to work as mfd driver child
> > - modified atmel_serial driver to work as mfd driver child
> > 
> > Radu Pirea (6):
> >   MAINTAINERS: add at91 usart mfd driver
> >   mfd: at91-usart: added mfd driver for usart
> >   MAINTAINERS: add at91 usart spi driver
> >   dt-bindings: add binding for at91-usart in spi mode
> >   spi: at91-usart: add driver for at91-usart as spi
> >   tty/serial: atmel: changed the driver to work under at91-usart mfd
> > 
> >  .../bindings/spi/microchip,at91-usart-spi.txt |  28 +
> >  MAINTAINERS                                   |  14 +
> >  drivers/mfd/Kconfig                           |  10 +
> >  drivers/mfd/Makefile                          |   1 +
> >  drivers/mfd/at91-usart.c                      |  81 +++
> >  drivers/spi/Kconfig                           |   9 +
> >  drivers/spi/Makefile                          |   1 +
> >  drivers/spi/spi-at91-usart.c                  | 545 ++++++++++++++++++
> >  drivers/tty/serial/Kconfig                    |   1 +
> >  drivers/tty/serial/atmel_serial.c             |  29 +-
> >  include/dt-bindings/mfd/at91-usart.h          |  17 +
> >  11 files changed, 722 insertions(+), 14 deletions(-)
> >  create mode 100644 Documentation/devicetree/bindings/spi/microchip,at91-usart-spi.txt
> >  create mode 100644 drivers/mfd/at91-usart.c
> >  create mode 100644 drivers/spi/spi-at91-usart.c
> >  create mode 100644 include/dt-bindings/mfd/at91-usart.h
> 
> Applied, thanks.

Whoops!  Ignore this, wrong patch!

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog