[PATCH v2 1/2] dt/bindings: Add bindings for PIC32 SPI peripheral

[PATCH v2 1/2] dt/bindings: Add bindings for PIC32 SPI peripheral

[Purna Chandra Mandal]

Signed-off-by: Purna Chandra Mandal <purna.mandal@microchip.com>

---

Changes in v2:
 - fix indentation
 - add space after comma
 - moved 'cs-gpios' section under 'required' properties.

 .../bindings/spi/microchip,spi-pic32.txt           | 34 ++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt

diff --git a/Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt b/Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt
new file mode 100644
index 0000000..79de379f
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt
@@ -0,0 +1,34 @@
+Microchip PIC32 SPI Master controller
+
+Required properties:
+- compatible: Should be "microchip,pic32mzda-spi".
+- reg: Address and length of register space for the device.
+- interrupts: Should contain all three spi interrupts in sequence
+              of <fault-irq>, <receive-irq>, <transmit-irq>.
+- interrupt-names: Should be "fault", "rx", "tx" in order.
+- clocks: Phandle of the clock generating SPI clock on the bus.
+- clock-names: Should be "mck0".
+- cs-gpios: Specifies the gpio pins to be used for chipselects.
+            See: Documentation/devicetree/bindings/spi/spi-bus.txt
+
+Optional properties:
+- dmas: Two or more DMA channel specifiers following the convention outlined
+        in Documentation/devicetree/bindings/dma/dma.txt
+- dma-names: Names for the dma channels. There must be at least one channel
+             named "spi-tx" for transmit and named "spi-rx" for receive.
+
+Example:
+
+spi1: spi@1f821000 {
+        compatible = "microchip,pic32mzda-spi";
+        reg = <0x1f821000 0x200>;
+        interrupts = <109 IRQ_TYPE_LEVEL_HIGH>,
+                     <110 IRQ_TYPE_LEVEL_HIGH>,
+                     <111 IRQ_TYPE_LEVEL_HIGH>;
+        interrupt-names = "fault", "rx", "tx";
+        clocks = <&PBCLK2>;
+        clock-names = "mck0";
+        cs-gpios = <&gpio3 4 GPIO_ACTIVE_LOW>;
+        dmas = <&dma 134>, <&dma 135>;
+        dma-names = "spi-rx", "spi-tx";
+};
-- 
1.8.3.1

[PATCH v2 1/2] dt/bindings: Add bindings for PIC32 SPI peripheral

[Purna Chandra Mandal]

Signed-off-by: Purna Chandra Mandal <purna.mandal-UWL1GkI3JZL3oGB3hsPCZA@public.gmane.org>

---

Changes in v2:
 - fix indentation
 - add space after comma
 - moved 'cs-gpios' section under 'required' properties.

 .../bindings/spi/microchip,spi-pic32.txt           | 34 ++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt

diff --git a/Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt b/Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt
new file mode 100644
index 0000000..79de379f
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt
@@ -0,0 +1,34 @@
+Microchip PIC32 SPI Master controller
+
+Required properties:
+- compatible: Should be "microchip,pic32mzda-spi".
+- reg: Address and length of register space for the device.
+- interrupts: Should contain all three spi interrupts in sequence
+              of <fault-irq>, <receive-irq>, <transmit-irq>.
+- interrupt-names: Should be "fault", "rx", "tx" in order.
+- clocks: Phandle of the clock generating SPI clock on the bus.
+- clock-names: Should be "mck0".
+- cs-gpios: Specifies the gpio pins to be used for chipselects.
+            See: Documentation/devicetree/bindings/spi/spi-bus.txt
+
+Optional properties:
+- dmas: Two or more DMA channel specifiers following the convention outlined
+        in Documentation/devicetree/bindings/dma/dma.txt
+- dma-names: Names for the dma channels. There must be at least one channel
+             named "spi-tx" for transmit and named "spi-rx" for receive.
+
+Example:
+
+spi1: spi@1f821000 {
+        compatible = "microchip,pic32mzda-spi";
+        reg = <0x1f821000 0x200>;
+        interrupts = <109 IRQ_TYPE_LEVEL_HIGH>,
+                     <110 IRQ_TYPE_LEVEL_HIGH>,
+                     <111 IRQ_TYPE_LEVEL_HIGH>;
+        interrupt-names = "fault", "rx", "tx";
+        clocks = <&PBCLK2>;
+        clock-names = "mck0";
+        cs-gpios = <&gpio3 4 GPIO_ACTIVE_LOW>;
+        dmas = <&dma 134>, <&dma 135>;
+        dma-names = "spi-rx", "spi-tx";
+};
-- 
1.8.3.1

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[PATCH v2 1/2] dt/bindings: Add bindings for PIC32 SPI peripheral

[Purna Chandra Mandal]

Signed-off-by: Purna Chandra Mandal <purna.mandal-UWL1GkI3JZL3oGB3hsPCZA@public.gmane.org>

---

Changes in v2:
 - fix indentation
 - add space after comma
 - moved 'cs-gpios' section under 'required' properties.

 .../bindings/spi/microchip,spi-pic32.txt           | 34 ++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt

diff --git a/Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt b/Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt
new file mode 100644
index 0000000..79de379f
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt
@@ -0,0 +1,34 @@
+Microchip PIC32 SPI Master controller
+
+Required properties:
+- compatible: Should be "microchip,pic32mzda-spi".
+- reg: Address and length of register space for the device.
+- interrupts: Should contain all three spi interrupts in sequence
+              of <fault-irq>, <receive-irq>, <transmit-irq>.
+- interrupt-names: Should be "fault", "rx", "tx" in order.
+- clocks: Phandle of the clock generating SPI clock on the bus.
+- clock-names: Should be "mck0".
+- cs-gpios: Specifies the gpio pins to be used for chipselects.
+            See: Documentation/devicetree/bindings/spi/spi-bus.txt
+
+Optional properties:
+- dmas: Two or more DMA channel specifiers following the convention outlined
+        in Documentation/devicetree/bindings/dma/dma.txt
+- dma-names: Names for the dma channels. There must be at least one channel
+             named "spi-tx" for transmit and named "spi-rx" for receive.
+
+Example:
+
+spi1: spi@1f821000 {
+        compatible = "microchip,pic32mzda-spi";
+        reg = <0x1f821000 0x200>;
+        interrupts = <109 IRQ_TYPE_LEVEL_HIGH>,
+                     <110 IRQ_TYPE_LEVEL_HIGH>,
+                     <111 IRQ_TYPE_LEVEL_HIGH>;
+        interrupt-names = "fault", "rx", "tx";
+        clocks = <&PBCLK2>;
+        clock-names = "mck0";
+        cs-gpios = <&gpio3 4 GPIO_ACTIVE_LOW>;
+        dmas = <&dma 134>, <&dma 135>;
+        dma-names = "spi-rx", "spi-tx";
+};
-- 
1.8.3.1

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[PATCH v2 1/2] dt/bindings: Add bindings for PIC32 SPI peripheral

[Purna Chandra Mandal]

Signed-off-by: Purna Chandra Mandal <purna.mandal@microchip.com>

---

Changes in v2:
 - fix indentation
 - add space after comma
 - moved 'cs-gpios' section under 'required' properties.

 .../bindings/spi/microchip,spi-pic32.txt           | 34 ++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt

diff --git a/Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt b/Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt
new file mode 100644
index 0000000..79de379f
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt
@@ -0,0 +1,34 @@
+Microchip PIC32 SPI Master controller
+
+Required properties:
+- compatible: Should be "microchip,pic32mzda-spi".
+- reg: Address and length of register space for the device.
+- interrupts: Should contain all three spi interrupts in sequence
+              of <fault-irq>, <receive-irq>, <transmit-irq>.
+- interrupt-names: Should be "fault", "rx", "tx" in order.
+- clocks: Phandle of the clock generating SPI clock on the bus.
+- clock-names: Should be "mck0".
+- cs-gpios: Specifies the gpio pins to be used for chipselects.
+            See: Documentation/devicetree/bindings/spi/spi-bus.txt
+
+Optional properties:
+- dmas: Two or more DMA channel specifiers following the convention outlined
+        in Documentation/devicetree/bindings/dma/dma.txt
+- dma-names: Names for the dma channels. There must be at least one channel
+             named "spi-tx" for transmit and named "spi-rx" for receive.
+
+Example:
+
+spi1: spi@1f821000 {
+        compatible = "microchip,pic32mzda-spi";
+        reg = <0x1f821000 0x200>;
+        interrupts = <109 IRQ_TYPE_LEVEL_HIGH>,
+                     <110 IRQ_TYPE_LEVEL_HIGH>,
+                     <111 IRQ_TYPE_LEVEL_HIGH>;
+        interrupt-names = "fault", "rx", "tx";
+        clocks = <&PBCLK2>;
+        clock-names = "mck0";
+        cs-gpios = <&gpio3 4 GPIO_ACTIVE_LOW>;
+        dmas = <&dma 134>, <&dma 135>;
+        dma-names = "spi-rx", "spi-tx";
+};
-- 
1.8.3.1

[PATCH v2 2/2] spi: spi-pic32: Add PIC32 SPI master driver

[Purna Chandra Mandal]

The PIC32 SPI driver is capable of performing SPI transfers
using PIO or external DMA engine. GPIO controlled /CS support
is made default in the driver for correct operation of the
controller. This can be enabled by adding "cs-gpios" property
of the SPI node in board dts file.

Signed-off-by: Purna Chandra Mandal <purna.mandal@microchip.com>

---

Changes in v2:
- drop internal function drain_rx_fifo()
- merge wrapper functions with callers wherever applicable
- sort includes alphabetically
- Kconfig: sort SPI_PIC32 alphabetically and add || COMPILE_TEST
- Makefile: sort SPI_PIC32 alphabetically
- replace cpu_relax() with ndelay() in disable_chip()
- drop spi controller driven /CS management completely, use only
  GPIO controller /CS.
- rename function names starting with 'spi' to avoid namespace conflict
- use .one_transfer() callback instead of .one_message().
- drop /CS assert-deassert functions as core provides those.
- fix race while completing transfer before disabling interrupt.

 drivers/spi/Kconfig     |    6 +
 drivers/spi/Makefile    |    1 +
 drivers/spi/spi-pic32.c | 1004 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1011 insertions(+)
 create mode 100644 drivers/spi/spi-pic32.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 7706416..22f973f 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -396,6 +396,12 @@ config SPI_ORION
 	help
 	  This enables using the SPI master controller on the Orion chips.
 
+config SPI_PIC32
+	tristate "Microchip PIC32 series SPI"
+	depends on MACH_PIC32 || COMPILE_TEST
+	help
+	  SPI driver for Microchip PIC32 SPI master controller.
+
 config SPI_PL022
 	tristate "ARM AMBA PL022 SSP controller"
 	depends on ARM_AMBA
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 8991ffc..1bcb417 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -60,6 +60,7 @@ obj-$(CONFIG_SPI_OMAP_100K)		+= spi-omap-100k.o
 obj-$(CONFIG_SPI_OMAP24XX)		+= spi-omap2-mcspi.o
 obj-$(CONFIG_SPI_TI_QSPI)		+= spi-ti-qspi.o
 obj-$(CONFIG_SPI_ORION)			+= spi-orion.o
+obj-$(CONFIG_SPI_PIC32)			+= spi-pic32.o
 obj-$(CONFIG_SPI_PL022)			+= spi-pl022.o
 obj-$(CONFIG_SPI_PPC4xx)		+= spi-ppc4xx.o
 spi-pxa2xx-platform-objs		:= spi-pxa2xx.o
diff --git a/drivers/spi/spi-pic32.c b/drivers/spi/spi-pic32.c
new file mode 100644
index 0000000..8627aa1
--- /dev/null
+++ b/drivers/spi/spi-pic32.c
@@ -0,0 +1,1004 @@
+/*
+ * Microchip PIC32 SPI controller driver.
+ *
+ * Purna Chandra Mandal <purna.mandal@microchip.com>
+ * Copyright (c) 2016, Microchip Technology Inc.
+ *
+ * This program is free software; you can distribute it and/or modify it
+ * under the terms of the GNU General Public License (Version 2) as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/highmem.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_gpio.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+
+/* SPI Register offsets */
+struct pic32_spi_regs {
+	u32 ctrl;
+	u32 ctrl_clr;
+	u32 ctrl_set;
+	u32 ctrl_inv;
+	u32 status;
+	u32 status_clr;
+	u32 status_set;
+	u32 status_inv;
+	u32 buf;
+	u32 reserved[3];
+	u32 baud;
+	u32 reserved2[3];
+	u32 ctrl2;
+	u32 ctrl2_clr;
+	u32 ctrl2_set;
+	u32 ctrl2_inv;
+};
+
+/* Bit fields in SPI Control Register */
+#define CTRL_RX_INT_SHIFT	0  /* Rx interrupt generation */
+#define  RX_FIFO_EMTPY		0
+#define  RX_FIFO_NOT_EMPTY	1 /* not empty */
+#define  RX_FIFO_HALF_FULL	2 /* full by half or more */
+#define  RX_FIFO_FULL		3 /* completely full */
+
+#define CTRL_TX_INT_SHIFT	2  /* TX interrupt generation */
+#define  TX_FIFO_ALL_EMPTY	0 /* completely empty */
+#define  TX_FIFO_EMTPY		1 /* empty */
+#define  TX_FIFO_HALF_EMPTY	2 /* empty by half or more */
+#define  TX_FIFO_NOT_FULL	3 /* atleast one empty */
+
+#define CTRL_MSTEN	BIT(5) /* enable master mode */
+#define CTRL_CKP	BIT(6) /* active low */
+#define CTRL_CKE	BIT(8) /* Tx on falling edge */
+#define CTRL_SMP	BIT(9) /* Rx at middle or end of tx */
+#define CTRL_BPW_MASK	0x03   /* bits per word/sample */
+#define CTRL_BPW_SHIFT	10
+#define  PIC32_BPW_8	0
+#define  PIC32_BPW_16	1
+#define  PIC32_BPW_32	2
+#define CTRL_ON		BIT(15) /* enable macro */
+#define CTRL_ENHBUF	BIT(16) /* enable enhanced buffering */
+#define CTRL_MCLKSEL	BIT(23) /* select clock source */
+#define CTRL_MSSEN	BIT(28) /* macro driven /SS */
+#define CTRL_FRMEN	BIT(31) /* enable framing mode */
+
+/* Bit fields in SPI Status Register */
+#define STAT_RF_EMPTY	BIT(5) /* RX Fifo empty */
+#define STAT_RX_OV	BIT(6) /* err, s/w needs to clear */
+#define STAT_TX_UR	BIT(8) /* UR in Framed SPI modes */
+#define STAT_FRM_ERR	BIT(12) /* Multiple Frame Sync pulse */
+#define STAT_TF_LVL_MASK	0x1F
+#define STAT_TF_LVL_SHIFT	16
+#define STAT_RF_LVL_MASK	0x1F
+#define STAT_RF_LVL_SHIFT	24
+
+/* Bit fields in Baud Register */
+#define BAUD_MASK		0x1ff
+
+/* Bit fields in Control2 Register */
+#define CTRL2_TX_UR_EN		BIT(10) /* Enable int on Tx under-run */
+#define CTRL2_RX_OV_EN		BIT(11) /* Enable int on Rx over-run */
+#define CTRL2_FRM_ERR_EN	BIT(12) /* Enable frame err int */
+
+/* Minimum DMA transfer size */
+#define PIC32_DMA_LEN_MIN	64
+
+struct pic32_spi {
+	dma_addr_t		dma_base;
+	struct pic32_spi_regs __iomem *regs;
+	int			fault_irq;
+	int			rx_irq;
+	int			tx_irq;
+	u32			fifo_n_byte; /* FIFO depth in bytes */
+	struct clk		*clk;
+	spinlock_t		lock;	/* lock */
+	struct spi_master	*master;
+	/* Current SPI device specific */
+	struct spi_device	*spi_dev;
+	u32			speed_hz; /* spi-clk rate */
+	u32			mode;
+#define PIC32F_XFER_PIO		0 /* do PIO transfer */
+#define PIC32F_DMA_PREP		1 /* DMA chnls configured */
+#define PIC32F_DMA_READY	2 /* buffer mapped and DMA issued */
+	unsigned long		flags;
+	u32			fifo_n_elm; /* FIFO depth in words */
+	enum dma_slave_buswidth	dma_width;
+	/* Current transfer state */
+	struct spi_message	*mesg;
+	const void		*tx;
+	const void		*tx_end;
+	const void		*rx;
+	const void		*rx_end;
+	int			len;
+	struct completion	xfer_done;
+	/* SPI FiFo accessor */
+	void (*rx_fifo)(struct pic32_spi *);
+	void (*tx_fifo)(struct pic32_spi *);
+};
+
+static bool pic32_spi_debug;
+
+static void pic32_spi_enable_chip(struct pic32_spi *pic32s)
+{
+	writel(CTRL_ON, &pic32s->regs->ctrl_set);
+}
+
+static void pic32_spi_disable_chip(struct pic32_spi *pic32s)
+{
+	writel(CTRL_ON, &pic32s->regs->ctrl_clr);
+
+	/* avoid read/write to SPI register at immediate next CPU clock */
+	ndelay(20);
+}
+
+static void pic32_spi_set_clk_rate(struct pic32_spi *pic32s, u32 spi_ck)
+{
+	u32 div;
+
+	/* div = (clk_in / (2 * spi_ck)) - 1 */
+	div = DIV_ROUND_CLOSEST(clk_get_rate(pic32s->clk), 2 * spi_ck) - 1;
+
+	writel(div & BAUD_MASK, &pic32s->regs->baud);
+}
+
+static u32 pic32_rx_fifo_level(struct pic32_spi *pic32s)
+{
+	u32 sr = readl(&pic32s->regs->status);
+
+	return (sr >> STAT_RF_LVL_SHIFT) & STAT_RF_LVL_MASK;
+}
+
+static u32 pic32_tx_fifo_level(struct pic32_spi *pic32s)
+{
+	u32 sr = readl(&pic32s->regs->status);
+
+	return (sr >> STAT_TF_LVL_SHIFT) & STAT_TF_LVL_MASK;
+}
+
+/* Return the max entries we can fill into tx fifo */
+static u32 pic32_tx_max(struct pic32_spi *pic32s, int n_bytes)
+{
+	u32 tx_left, tx_room, rxtx_gap;
+
+	tx_left = (pic32s->tx_end - pic32s->tx) / n_bytes;
+	tx_room = pic32s->fifo_n_elm - pic32_tx_fifo_level(pic32s);
+
+	/*
+	 * Another concern is about the tx/rx mismatch, we
+	 * though to use (pic32s->fifo_n_byte - rxfl - txfl) as
+	 * one maximum value for tx, but it doesn't cover the
+	 * data which is out of tx/rx fifo and inside the
+	 * shift registers. So a ctrl from sw point of
+	 * view is taken.
+	 */
+	rxtx_gap = ((pic32s->rx_end - pic32s->rx) -
+		    (pic32s->tx_end - pic32s->tx)) / n_bytes;
+	return min3(tx_left, tx_room, (u32)(pic32s->fifo_n_elm - rxtx_gap));
+}
+
+/* Return the max entries we should read out of rx fifo */
+static u32 pic32_rx_max(struct pic32_spi *pic32s, int n_bytes)
+{
+	u32 rx_left = (pic32s->rx_end - pic32s->rx) / n_bytes;
+
+	return min_t(u32, rx_left, pic32_rx_fifo_level(pic32s));
+}
+
+#define BUILD_SPI_FIFO_RW(__name, __type, __bwl)		\
+static void pic32_spi_rx_##__name(struct pic32_spi *pic32s)	\
+{								\
+	__type v;						\
+	u32 mx = pic32_rx_max(pic32s, sizeof(__type));		\
+	for (; mx; mx--) {					\
+		v = read##__bwl(&pic32s->regs->buf);		\
+		if (pic32s->rx_end - pic32s->len)		\
+			*(__type *)(pic32s->rx) = v;		\
+		pic32s->rx += sizeof(__type);			\
+	}							\
+}								\
+								\
+static void pic32_spi_tx_##__name(struct pic32_spi *pic32s)	\
+{								\
+	__type v;						\
+	u32 mx = pic32_tx_max(pic32s, sizeof(__type));		\
+	for (; mx ; mx--) {					\
+		v = (__type)~0U;				\
+		if (pic32s->tx_end - pic32s->len)		\
+			v = *(__type *)(pic32s->tx);		\
+		write##__bwl(v, &pic32s->regs->buf);		\
+		pic32s->tx += sizeof(__type);			\
+	}							\
+}
+
+BUILD_SPI_FIFO_RW(byte, u8, b);
+BUILD_SPI_FIFO_RW(word, u16, w);
+BUILD_SPI_FIFO_RW(dword, u32, l);
+
+static void pic32_err_stop(struct pic32_spi *pic32s, const char *msg)
+{
+	/* Stop h/w */
+	pic32_spi_disable_chip(pic32s);
+
+	/* disable all interrupts */
+	disable_irq_nosync(pic32s->fault_irq);
+	disable_irq_nosync(pic32s->rx_irq);
+	disable_irq_nosync(pic32s->tx_irq);
+
+	/* Show err message and abort xfer with err */
+	dev_err(&pic32s->master->dev, "%s\n", msg);
+	pic32s->mesg->status = -EIO;
+	complete(&pic32s->xfer_done);
+
+	dev_err(&pic32s->master->dev, "irq: disable all\n");
+}
+
+static irqreturn_t pic32_spi_fault_irq(int irq, void *dev_id)
+{
+	struct pic32_spi *pic32s = dev_id;
+	irqreturn_t ret = IRQ_HANDLED;
+	u32 status;
+
+	spin_lock(&pic32s->lock);
+
+	status = readl(&pic32s->regs->status);
+
+	/* Error handling */
+	if (status & (STAT_RX_OV | STAT_TX_UR)) {
+		writel(STAT_RX_OV, &pic32s->regs->status_clr);
+		writel(STAT_TX_UR, &pic32s->regs->status_clr);
+		pic32_err_stop(pic32s, "err_irq: fifo ov/ur-run\n");
+		goto exit_irq;
+	}
+
+	if (status & STAT_FRM_ERR) {
+		pic32_err_stop(pic32s, "err_irq: frame error");
+		goto exit_irq;
+	}
+
+	if (!pic32s->mesg) {
+		pic32_err_stop(pic32s, "err_irq: mesg error");
+		ret = IRQ_NONE;
+		goto exit_irq;
+	}
+
+exit_irq:
+	spin_unlock(&pic32s->lock);
+
+	return ret;
+}
+
+static irqreturn_t pic32_spi_rx_irq(int irq, void *dev_id)
+{
+	struct pic32_spi *pic32s = dev_id;
+
+	spin_lock(&pic32s->lock);
+
+	pic32s->rx_fifo(pic32s);
+
+	/* rx complete? */
+	if (pic32s->rx_end == pic32s->rx) {
+		/* mask & disable all interrupts */
+		disable_irq_nosync(pic32s->fault_irq);
+		disable_irq_nosync(pic32s->rx_irq);
+
+		/* complete current xfer */
+		complete(&pic32s->xfer_done);
+	}
+
+	spin_unlock(&pic32s->lock);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t pic32_spi_tx_irq(int irq, void *dev_id)
+{
+	struct pic32_spi *pic32s = dev_id;
+
+	spin_lock(&pic32s->lock);
+
+	pic32s->tx_fifo(pic32s);
+
+	/* tx complete? mask and disable tx interrupt */
+	if (pic32s->tx_end == pic32s->tx)
+		disable_irq_nosync(pic32s->tx_irq);
+
+	spin_unlock(&pic32s->lock);
+
+	return IRQ_HANDLED;
+}
+
+static void pic32_spi_dma_rx_notify(void *data)
+{
+	struct pic32_spi *pic32s = data;
+
+	complete(&pic32s->xfer_done);
+}
+
+static int pic32_spi_poll_transfer(struct pic32_spi *pic32s,
+				   unsigned long timeout)
+{
+	unsigned long deadline;
+
+	deadline = timeout + jiffies;
+	for (;;) {
+		pic32s->tx_fifo(pic32s);
+		cpu_relax();
+
+		pic32s->rx_fifo(pic32s);
+		cpu_relax();
+
+		/* received sufficient data */
+		if (pic32s->rx >= pic32s->rx_end)
+			break;
+
+		/* timedout ? */
+		if (time_after_eq(jiffies, deadline))
+			return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int pic32_spi_dma_transfer(struct pic32_spi *pic32s,
+				  struct spi_transfer *xfer)
+{
+	struct spi_master *master = pic32s->master;
+	struct dma_async_tx_descriptor *desc_rx;
+	struct dma_async_tx_descriptor *desc_tx;
+	dma_cookie_t cookie;
+	int ret;
+
+	if (!master->dma_rx || !master->dma_tx)
+		return -ENODEV;
+
+	desc_rx = dmaengine_prep_slave_sg(master->dma_rx,
+					  xfer->rx_sg.sgl,
+					  xfer->rx_sg.nents,
+					  DMA_FROM_DEVICE,
+					  DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!desc_rx) {
+		ret = -EINVAL;
+		goto err_dma;
+	}
+
+	desc_tx = dmaengine_prep_slave_sg(master->dma_tx,
+					  xfer->tx_sg.sgl,
+					  xfer->tx_sg.nents,
+					  DMA_TO_DEVICE,
+					  DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!desc_tx) {
+		ret = -EINVAL;
+		goto err_dma;
+	}
+
+	dev_vdbg(&master->dev, "dma_xfer %p: len %u, tx %p(%p), rx %p(%p)\n",
+		 xfer, xfer->len,
+		 xfer->tx_buf, (void *)xfer->tx_dma,
+		 xfer->rx_buf, (void *)xfer->rx_dma);
+
+	/* Put callback on the RX transfer, that should finish last */
+	desc_rx->callback = pic32_spi_dma_rx_notify;
+	desc_rx->callback_param = pic32s;
+
+	cookie = dmaengine_submit(desc_rx);
+	ret = dma_submit_error(cookie);
+	if (ret)
+		goto err_dma;
+
+	cookie = dmaengine_submit(desc_tx);
+	ret = dma_submit_error(cookie);
+	if (ret)
+		goto err_dma_tx;
+
+	dma_async_issue_pending(master->dma_rx);
+	dma_async_issue_pending(master->dma_tx);
+	set_bit(PIC32F_DMA_READY, &pic32s->flags);
+
+	return 0;
+
+err_dma_tx:
+	dmaengine_terminate_all(master->dma_rx);
+err_dma:
+	return ret;
+}
+
+static int pic32_spi_dma_config(struct pic32_spi *pic32s, u32 dma_width)
+{
+	int buf_offset = offsetof(struct pic32_spi_regs, buf);
+	struct spi_master *master = pic32s->master;
+	struct dma_slave_config cfg;
+	int err;
+
+	cfg.device_fc = true;
+	cfg.dst_addr = pic32s->dma_base + buf_offset;
+	cfg.dst_addr_width = dma_width;
+	cfg.dst_maxburst = pic32s->fifo_n_elm / 2; /* drain one-half */
+	cfg.src_addr = pic32s->dma_base + buf_offset;
+	cfg.src_addr_width = dma_width;
+	cfg.src_maxburst = pic32s->fifo_n_elm / 2; /* fill one-half */
+	cfg.slave_id = pic32s->tx_irq;
+	cfg.direction = DMA_MEM_TO_DEV;
+	err = dmaengine_slave_config(master->dma_tx, &cfg);
+	if (err) {
+		dev_err(&master->dev, "configure tx dma channel failed\n");
+		return err;
+	}
+
+	cfg.slave_id = pic32s->rx_irq;
+	cfg.direction = DMA_DEV_TO_MEM;
+	err = dmaengine_slave_config(master->dma_rx, &cfg);
+	if (err)
+		dev_err(&master->dev, "configure rx dma channel failed\n");
+
+	return err;
+}
+
+static void pic32_spi_set_word_size(struct pic32_spi *pic32s, u8 bits_per_word)
+{
+	enum dma_slave_buswidth dma_buswidth;
+	u32 spi_buswidth, v;
+
+	switch (bits_per_word) {
+	default:
+	case 8:
+		pic32s->rx_fifo = pic32_spi_rx_byte;
+		pic32s->tx_fifo = pic32_spi_tx_byte;
+		spi_buswidth = PIC32_BPW_8;
+		dma_buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
+		break;
+	case 16:
+		pic32s->rx_fifo = pic32_spi_rx_word;
+		pic32s->tx_fifo = pic32_spi_tx_word;
+		spi_buswidth = PIC32_BPW_16;
+		dma_buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
+		break;
+	case 32:
+		pic32s->rx_fifo = pic32_spi_rx_dword;
+		pic32s->tx_fifo = pic32_spi_tx_dword;
+		spi_buswidth = PIC32_BPW_32;
+		dma_buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES;
+		break;
+	}
+
+	/* calculate maximum number of words fifos can hold */
+	pic32s->fifo_n_elm = DIV_ROUND_UP(pic32s->fifo_n_byte,
+					  bits_per_word >> 3);
+	/* set word size */
+	v = readl(&pic32s->regs->ctrl);
+	v &= ~(CTRL_BPW_MASK << CTRL_BPW_SHIFT);
+	v |= spi_buswidth << CTRL_BPW_SHIFT;
+	writel(v, &pic32s->regs->ctrl);
+
+	/* re-configure dma width, if required */
+	if (test_bit(PIC32F_DMA_PREP, &pic32s->flags) &&
+	    (dma_buswidth != pic32s->dma_width)) {
+		pic32_spi_dma_config(pic32s, dma_buswidth);
+		pic32s->dma_width = dma_buswidth;
+	}
+}
+
+static int pic32_spi_prepare_message(struct spi_master *master,
+				     struct spi_message *msg)
+{
+	struct spi_device *spi = msg->spi;
+	struct spi_transfer *xfer;
+	struct pic32_spi *pic32s;
+
+	pic32s = spi_master_get_devdata(master);
+
+	pic32s->mesg = msg;
+	pic32_spi_disable_chip(pic32s);
+
+	if (!pic32_spi_debug)
+		return 0;
+
+	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+		dev_dbg(&spi->dev, "  xfer %p: len %u tx %p rx %p\n",
+			xfer, xfer->len, xfer->tx_buf, xfer->rx_buf);
+		print_hex_dump(KERN_DEBUG, "tx_buf ",
+			       DUMP_PREFIX_ADDRESS,
+			       16, 1, xfer->tx_buf,
+			       min_t(u32, xfer->len, 16), 1);
+	}
+
+	return 0;
+}
+
+static bool pic32_spi_can_dma(struct spi_master *master,
+			      struct spi_device *spi,
+			      struct spi_transfer *xfer)
+{
+	struct pic32_spi *pic32s = spi_master_get_devdata(master);
+
+	return (xfer->len >= PIC32_DMA_LEN_MIN) &&
+	       test_bit(PIC32F_DMA_PREP, &pic32s->flags);
+}
+
+static int pic32_spi_one_transfer(struct spi_master *master,
+				  struct spi_device *spi,
+				  struct spi_transfer *transfer)
+{
+	struct pic32_spi *pic32s;
+	unsigned long flags;
+	int ret;
+
+	pic32s = spi_master_get_devdata(master);
+
+	/* set current transfer information */
+	pic32s->tx = (const void *)transfer->tx_buf;
+	pic32s->rx = (const void *)transfer->rx_buf;
+	pic32s->tx_end = pic32s->tx + transfer->len;
+	pic32s->rx_end = pic32s->rx + transfer->len;
+	pic32s->len = transfer->len;
+
+	if (transfer->speed_hz && (transfer->speed_hz != pic32s->speed_hz)) {
+		pic32_spi_set_clk_rate(pic32s, transfer->speed_hz);
+		pic32s->speed_hz = transfer->speed_hz;
+	}
+
+	if (transfer->bits_per_word)
+		pic32_spi_set_word_size(pic32s, transfer->bits_per_word);
+
+	pic32_spi_enable_chip(pic32s);
+	reinit_completion(&pic32s->xfer_done);
+
+	/* DMA transfer mode ? */
+	if (transfer->rx_sg.nents && transfer->tx_sg.nents) {
+		ret = pic32_spi_dma_transfer(pic32s, transfer);
+		if (ret) {
+			dev_err(&spi->dev, "dma submit error\n");
+			/* fallback: PIO transfer */
+		} else {
+			goto out_wait_for_xfer;
+		}
+	}
+
+	/* polling transfer mode */
+	if (test_bit(PIC32F_XFER_PIO, &pic32s->flags))
+		return pic32_spi_poll_transfer(pic32s, 2 * HZ);
+
+	/* interrupt driven PIO transfer */
+	spin_lock_irqsave(&pic32s->lock, flags);
+	enable_irq(pic32s->fault_irq);
+	enable_irq(pic32s->rx_irq);
+	enable_irq(pic32s->tx_irq);
+	spin_unlock_irqrestore(&pic32s->lock, flags);
+
+out_wait_for_xfer:
+	/* wait for completion */
+	ret = wait_for_completion_timeout(&pic32s->xfer_done, 2 * HZ);
+	if (ret <= 0) {
+		dev_err(&spi->dev, "wait timedout\n");
+		if (test_bit(PIC32F_DMA_READY, &pic32s->flags)) {
+			dmaengine_terminate_all(master->dma_rx);
+			dmaengine_terminate_all(master->dma_rx);
+		}
+		ret = -ETIMEDOUT;
+	} else {
+		ret = 0;
+	}
+
+	clear_bit(PIC32F_DMA_READY, &pic32s->flags);
+	return ret;
+}
+
+static int pic32_spi_unprepare_message(struct spi_master *master,
+				       struct spi_message *msg)
+{
+	struct spi_transfer *xfer;
+	struct pic32_spi *pic32s;
+
+	pic32s = spi_master_get_devdata(master);
+
+	pic32_spi_disable_chip(pic32s);
+
+	if (!pic32_spi_debug)
+		return 0;
+
+	list_for_each_entry(xfer, &msg->transfers, transfer_list)
+		print_hex_dump(KERN_DEBUG, "rx_buf ",
+			       DUMP_PREFIX_ADDRESS,
+			       16, 1, xfer->rx_buf,
+			       min_t(u32, xfer->len, 32), 1);
+
+	return 0;
+}
+
+static void pic32_spi_cleanup(struct spi_device *spi)
+{
+	struct pic32_spi *pic32s;
+	int cs_high;
+
+	pic32s = spi_master_get_devdata(spi->master);
+
+	/* disable chip */
+	pic32_spi_disable_chip(pic32s);
+
+	/* release cs-gpio */
+	cs_high = pic32s->mode & SPI_CS_HIGH;
+	gpio_direction_output(spi->cs_gpio, !cs_high);
+	gpio_free(spi->cs_gpio);
+
+	/* reset reference */
+	pic32s->spi_dev = NULL;
+	pic32s->speed_hz = 0;
+}
+
+/* This may be called multiple times by same spi dev */
+static int pic32_spi_setup(struct spi_device *spi)
+{
+	struct pic32_spi *pic32s;
+	int cs_high, ret;
+	u32 v;
+
+	pic32s = spi_master_get_devdata(spi->master);
+
+	/* SPI master supports only one spi-device at a time.
+	 * So multiple spi_setup() to different devices is not allowed.
+	 */
+	if (unlikely(pic32s->spi_dev && (pic32s->spi_dev != spi))) {
+		dev_err(&spi->dev, "spi-master already associated with %s\n",
+			dev_name(&pic32s->spi_dev->dev));
+		return -EBUSY;
+	}
+
+	/* stop current transaction & release resource */
+	if (pic32s->spi_dev == spi)
+		pic32_spi_cleanup(spi);
+
+	pic32s->spi_dev = spi;
+
+	if (!spi->bits_per_word) {
+		dev_err(&spi->dev, "No bits_per_word defined\n");
+		return -EINVAL;
+	}
+
+	if (!spi->max_speed_hz) {
+		dev_err(&spi->dev, "No max speed HZ parameter\n");
+		return -EINVAL;
+	}
+
+	pic32_spi_disable_chip(pic32s);
+
+	pic32_spi_set_word_size(pic32s, spi->bits_per_word);
+
+	pic32s->speed_hz = spi->max_speed_hz;
+	pic32_spi_set_clk_rate(pic32s, spi->max_speed_hz);
+
+	/* set spi mode */
+	v = readl(&pic32s->regs->ctrl);
+
+	/* active low */
+	if (spi->mode & SPI_CPOL)
+		v |= CTRL_CKP;
+	else
+		v &= ~CTRL_CKP;
+
+	/* tx on rising edge */
+	if (spi->mode & SPI_CPHA)
+		v &= ~CTRL_CKE;
+	else
+		v |= CTRL_CKE;
+
+	/* rx at end of tx */
+	v |= CTRL_SMP;
+	writel(v, &pic32s->regs->ctrl);
+	pic32s->mode = spi->mode;
+
+	/* PIC32 spi ctrller can drive /SS during transfer depending
+	 * on tx fifo fill-level. SS will stay asserted as long as TX
+	 * fifo is non-empty, else will be deasserted confirming
+	 * completion of the ongoing transfer.
+	 * So we will force manual /SS handling by GPIO toggling.
+	 */
+	if (!gpio_is_valid(spi->cs_gpio))
+		return -EINVAL;
+
+	cs_high = pic32s->mode & SPI_CS_HIGH;
+	ret = gpio_request(spi->cs_gpio, dev_name(&spi->dev));
+	if (!ret) {
+		gpio_direction_output(spi->cs_gpio, !cs_high);
+		dev_vdbg(&spi->dev,
+			 "gpio-%d configured for spics (%s)\n",
+			 spi->cs_gpio, cs_high ? "cs_high" : "cs_low");
+	}
+	writel(CTRL_MSSEN, &pic32s->regs->ctrl_clr);
+
+	dev_vdbg(&spi->master->dev,
+		 "successfully registered spi-device %s\n",
+		 dev_name(&spi->dev));
+	return 0;
+}
+
+static int pic32_spi_dma_prep(struct pic32_spi *pic32s, struct device *dev)
+{
+	struct spi_master *master = pic32s->master;
+	dma_cap_mask_t mask;
+	int err;
+
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+
+	master->dma_rx = dma_request_slave_channel_compat(mask, NULL, NULL,
+							  dev, "spi-rx");
+	if (!master->dma_rx) {
+		dev_err(dev, "RX channel not found, SPI unable to use DMA\n");
+		err = -EBUSY;
+		goto out_err;
+	}
+
+	master->dma_tx = dma_request_slave_channel_compat(mask, NULL, NULL,
+							  dev, "spi-tx");
+	if (!master->dma_tx) {
+		dev_err(dev, "TX channel not found, SPI unable to use DMA\n");
+		err = -EBUSY;
+		goto out_err;
+	}
+
+	pic32s->dma_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+	err = pic32_spi_dma_config(pic32s, pic32s->dma_width);
+	if (err)
+		goto out_err;
+
+	/* DMA chnls allocated and prepared */
+	set_bit(PIC32F_DMA_PREP, &pic32s->flags);
+
+	dev_dbg(dev, "Using %s (tx) and %s (rx) for DMA transfers\n",
+		dma_chan_name(master->dma_tx),
+		dma_chan_name(master->dma_rx));
+	return 0;
+
+out_err:
+	if (master->dma_rx)
+		dma_release_channel(master->dma_rx);
+
+	if (master->dma_tx)
+		dma_release_channel(master->dma_tx);
+
+	return err;
+}
+
+static void pic32_spi_dma_unprep(struct pic32_spi *pic32s)
+{
+	if (!test_bit(PIC32F_DMA_PREP, &pic32s->flags))
+		return;
+
+	clear_bit(PIC32F_DMA_PREP, &pic32s->flags);
+	if (pic32s->master->dma_rx)
+		dma_release_channel(pic32s->master->dma_rx);
+
+	if (pic32s->master->dma_tx)
+		dma_release_channel(pic32s->master->dma_tx);
+}
+
+static void pic32_spi_hw_init(struct pic32_spi *pic32s)
+{
+	u32 v;
+
+	/* disable module */
+	pic32_spi_disable_chip(pic32s);
+
+	v = readl(&pic32s->regs->ctrl);
+	/* enable enhanced fifo of 128bit deep */
+	v |= CTRL_ENHBUF;
+	pic32s->fifo_n_byte = 16;
+
+	/* disable framing mode */
+	v &= ~CTRL_FRMEN;
+
+	/* enable master mode while disabled */
+	v |= CTRL_MSTEN;
+
+	/* set tx fifo threshold interrupt */
+	v &= ~(0x3 << CTRL_TX_INT_SHIFT);
+	v |= (TX_FIFO_HALF_EMPTY << CTRL_TX_INT_SHIFT);
+
+	/* set rx fifo threshold interrupt */
+	v &= ~(0x3 << CTRL_RX_INT_SHIFT);
+	v |= (RX_FIFO_NOT_EMPTY << CTRL_RX_INT_SHIFT);
+
+	/* select clk source */
+	v &= ~CTRL_MCLKSEL;
+
+	writel(v, &pic32s->regs->ctrl);
+
+	/* enable error reporting */
+	v = CTRL2_TX_UR_EN | CTRL2_RX_OV_EN | CTRL2_FRM_ERR_EN;
+	writel(v, &pic32s->regs->ctrl2_set);
+}
+
+static int pic32_spi_hw_probe(struct platform_device *pdev,
+			      struct pic32_spi *pic32s)
+{
+	struct resource *mem;
+	int ret;
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	pic32s->regs = devm_ioremap_resource(&pdev->dev, mem);
+	if (!pic32s->regs) {
+		dev_err(&pdev->dev, "mem map failed\n");
+		return -ENOMEM;
+	}
+	pic32s->dma_base = mem->start;
+
+	/* get irq resources: err-irq, rx-irq, tx-irq */
+	pic32s->fault_irq = platform_get_irq_byname(pdev, "fault");
+	if (pic32s->fault_irq < 0)
+		dev_warn(&pdev->dev, "no fault-irq found\n");
+
+	pic32s->rx_irq = platform_get_irq_byname(pdev, "rx");
+	if (pic32s->rx_irq < 0)
+		dev_warn(&pdev->dev, "no rx-irq found\n");
+
+	pic32s->tx_irq = platform_get_irq_byname(pdev, "tx");
+	if (pic32s->tx_irq < 0)
+		dev_warn(&pdev->dev, "no tx-irq found\n");
+
+	/* get clock */
+	pic32s->clk = devm_clk_get(&pdev->dev, "mck0");
+	if (IS_ERR(pic32s->clk)) {
+		dev_err(&pdev->dev, "err, no clk found\n");
+		ret = PTR_ERR(pic32s->clk);
+		goto err_unmap_mem;
+	}
+
+	ret = clk_prepare_enable(pic32s->clk);
+	if (ret)
+		goto err_unmap_mem;
+
+	/* initialize module */
+	pic32_spi_hw_init(pic32s);
+
+	return 0;
+
+err_unmap_mem:
+	dev_err(&pdev->dev, "hw_probe failed, ret %d\n", ret);
+	return ret;
+}
+
+static int pic32_spi_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct spi_master *master;
+	struct pic32_spi *pic32s;
+	int ret;
+
+	master = spi_alloc_master(dev, sizeof(*pic32s));
+	if (!master)
+		return -ENOMEM;
+
+	pic32s = spi_master_get_devdata(master);
+	pic32s->master = master;
+
+	ret = pic32_spi_hw_probe(pdev, pic32s);
+	if (ret) {
+		dev_err(&pdev->dev, "hw probe failed.\n");
+		goto err_free_master;
+	}
+
+	master->dev.of_node	= of_node_get(pdev->dev.of_node);
+	master->mode_bits	= SPI_MODE_3 | SPI_MODE_0 | SPI_CS_HIGH;
+	master->num_chipselect	= 1; /* single chip-select */
+	master->max_speed_hz	= clk_get_rate(pic32s->clk);
+	master->setup		= pic32_spi_setup;
+	master->cleanup		= pic32_spi_cleanup;
+	master->flags		= SPI_MASTER_MUST_TX | SPI_MASTER_MUST_RX;
+	master->bits_per_word_mask	= SPI_BPW_RANGE_MASK(8, 32);
+	master->prepare_message		= pic32_spi_prepare_message;
+	master->transfer_one		= pic32_spi_one_transfer;
+	master->unprepare_message	= pic32_spi_unprepare_message;
+
+	/* DMA support */
+	ret = pic32_spi_dma_prep(pic32s, dev);
+	if (test_bit(PIC32F_DMA_PREP, &pic32s->flags))
+		master->can_dma	= pic32_spi_can_dma;
+
+	init_completion(&pic32s->xfer_done);
+	spin_lock_init(&pic32s->lock);
+
+	/* install irq handlers (with irq-disabled) */
+	irq_set_status_flags(pic32s->fault_irq, IRQ_NOAUTOEN);
+	ret = devm_request_irq(dev, pic32s->fault_irq,
+			       pic32_spi_fault_irq, IRQF_NO_THREAD,
+			       dev_name(dev), pic32s);
+	if (ret < 0) {
+		dev_warn(dev, "request fault-irq %d\n", pic32s->rx_irq);
+		set_bit(PIC32F_XFER_PIO, &pic32s->flags);
+		goto irq_request_done;
+	}
+
+	/* receive interrupt handler */
+	irq_set_status_flags(pic32s->rx_irq, IRQ_NOAUTOEN);
+	ret = devm_request_irq(dev, pic32s->rx_irq,
+			       pic32_spi_rx_irq, IRQF_NO_THREAD, dev_name(dev),
+			       pic32s);
+	if (ret < 0) {
+		dev_warn(dev, "request rx-irq %d\n", pic32s->rx_irq);
+		set_bit(PIC32F_XFER_PIO, &pic32s->flags);
+		goto irq_request_done;
+	}
+
+	/* transmit interrupt handler */
+	irq_set_status_flags(pic32s->tx_irq, IRQ_NOAUTOEN);
+	ret = devm_request_irq(dev, pic32s->tx_irq,
+			       pic32_spi_tx_irq, IRQF_NO_THREAD, dev_name(dev),
+			       pic32s);
+	if (ret < 0) {
+		dev_warn(dev, "request tx-irq %d\n", pic32s->tx_irq);
+		set_bit(PIC32F_XFER_PIO, &pic32s->flags);
+		goto irq_request_done;
+	}
+
+irq_request_done:
+	/* register master */
+	ret = devm_spi_register_master(dev, master);
+	if (ret) {
+		dev_err(&master->dev, "failed registering spi master\n");
+		goto err_hw_remove;
+	}
+
+	platform_set_drvdata(pdev, pic32s);
+
+	return 0;
+
+err_hw_remove:
+	/* disable hw */
+	pic32_spi_disable_chip(pic32s);
+
+	/* disable clk */
+	if (!IS_ERR_OR_NULL(pic32s->clk))
+		clk_disable_unprepare(pic32s->clk);
+err_free_master:
+	spi_master_put(master);
+	return ret;
+}
+
+static int pic32_spi_remove(struct platform_device *pdev)
+{
+	struct pic32_spi *pic32s;
+
+	pic32s = platform_get_drvdata(pdev);
+	pic32_spi_disable_chip(pic32s);
+	clk_disable_unprepare(pic32s->clk);
+	pic32_spi_dma_unprep(pic32s);
+
+	return 0;
+}
+
+static const struct of_device_id pic32_spi_of_match[] = {
+	{.compatible = "microchip,pic32mzda-spi",},
+	{},
+};
+MODULE_DEVICE_TABLE(of, pic32_spi_of_match);
+
+static struct platform_driver pic32_spi_driver = {
+	.driver = {
+		.name = "spi-pic32",
+		.owner = THIS_MODULE,
+		.of_match_table = of_match_ptr(pic32_spi_of_match),
+	},
+	.probe = pic32_spi_probe,
+	.remove = pic32_spi_remove,
+};
+
+module_platform_driver(pic32_spi_driver);
+
+MODULE_AUTHOR("Purna Chandra Mandal <purna.mandal@microchip.com>");
+MODULE_DESCRIPTION("Microchip SPI driver for PIC32 SPI controller.");
+MODULE_LICENSE("GPL v2");
-- 
1.8.3.1

[PATCH] spi: spi-pic32: fix platform_no_drv_owner.cocci warnings

[kbuild test robot]

drivers/spi/spi-pic32.c:993:3-8: No need to set .owner here. The core will do it.

 Remove .owner field if calls are used which set it automatically

Generated by: scripts/coccinelle/api/platform_no_drv_owner.cocci

CC: Purna Chandra Mandal <purna.mandal@microchip.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
---

 spi-pic32.c |    1 -
 1 file changed, 1 deletion(-)

--- a/drivers/spi/spi-pic32.c
+++ b/drivers/spi/spi-pic32.c
@@ -990,7 +990,6 @@ MODULE_DEVICE_TABLE(of, pic32_spi_of_mat
 static struct platform_driver pic32_spi_driver = {
 	.driver = {
 		.name = "spi-pic32",
-		.owner = THIS_MODULE,
 		.of_match_table = of_match_ptr(pic32_spi_of_match),
 	},
 	.probe = pic32_spi_probe,

Re: [PATCH v2 2/2] spi: spi-pic32: Add PIC32 SPI master driver

[kbuild test robot]

Hi Purna,

[auto build test WARNING on robh/for-next]
[also build test WARNING on v4.5-rc6 next-20160303]
[cannot apply to spi/for-next]
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]

url:    https://github.com/0day-ci/linux/commits/Purna-Chandra-Mandal/dt-bindings-Add-bindings-for-PIC32-SPI-peripheral/20160304-214814
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux for-next


coccinelle warnings: (new ones prefixed by >>)

>> drivers/spi/spi-pic32.c:993:3-8: No need to set .owner here. The core will do it.

Please review and possibly fold the followup patch.

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[PATCH] spi: spi-pic32: fix platform_no_drv_owner.cocci warnings

[kbuild test robot]

drivers/spi/spi-pic32.c:993:3-8: No need to set .owner here. The core will do it.

 Remove .owner field if calls are used which set it automatically

Generated by: scripts/coccinelle/api/platform_no_drv_owner.cocci

CC: Purna Chandra Mandal <purna.mandal-UWL1GkI3JZL3oGB3hsPCZA@public.gmane.org>
Signed-off-by: Fengguang Wu <fengguang.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---

 spi-pic32.c |    1 -
 1 file changed, 1 deletion(-)

--- a/drivers/spi/spi-pic32.c
+++ b/drivers/spi/spi-pic32.c
@@ -990,7 +990,6 @@ MODULE_DEVICE_TABLE(of, pic32_spi_of_mat
 static struct platform_driver pic32_spi_driver = {
 	.driver = {
 		.name = "spi-pic32",
-		.owner = THIS_MODULE,
 		.of_match_table = of_match_ptr(pic32_spi_of_match),
 	},
 	.probe = pic32_spi_probe,
--
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Re: [PATCH v2 2/2] spi: spi-pic32: Add PIC32 SPI master driver

[kbuild test robot]

Hi Purna,

[auto build test WARNING on robh/for-next]
[also build test WARNING on v4.5-rc6 next-20160303]
[cannot apply to spi/for-next]
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]

url:    https://github.com/0day-ci/linux/commits/Purna-Chandra-Mandal/dt-bindings-Add-bindings-for-PIC32-SPI-peripheral/20160304-214814
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux for-next


coccinelle warnings: (new ones prefixed by >>)

>> drivers/spi/spi-pic32.c:993:3-8: No need to set .owner here. The core will do it.

Please review and possibly fold the followup patch.

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
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Re: [PATCH v2 2/2] spi: spi-pic32: Add PIC32 SPI master driver

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 242 bytes --]

On Fri, Mar 04, 2016 at 07:14:42PM +0530, Purna Chandra Mandal wrote:
> The PIC32 SPI driver is capable of performing SPI transfers
> using PIO or external DMA engine. GPIO controlled /CS support

I don't seem to have patch 1 in this series.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 473 bytes --]

Re: [PATCH v2 2/2] spi: spi-pic32: Add PIC32 SPI master driver

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 242 bytes --]

On Fri, Mar 04, 2016 at 07:14:42PM +0530, Purna Chandra Mandal wrote:
> The PIC32 SPI driver is capable of performing SPI transfers
> using PIO or external DMA engine. GPIO controlled /CS support

I don't seem to have patch 1 in this series.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 473 bytes --]

Re: [PATCH v2 1/2] dt/bindings: Add bindings for PIC32 SPI peripheral

[Rob Herring]

On Fri, Mar 04, 2016 at 07:14:41PM +0530, Purna Chandra Mandal wrote:
> Signed-off-by: Purna Chandra Mandal <purna.mandal@microchip.com>
> 
> ---
> 
> Changes in v2:
>  - fix indentation
>  - add space after comma
>  - moved 'cs-gpios' section under 'required' properties.
> 
>  .../bindings/spi/microchip,spi-pic32.txt           | 34 ++++++++++++++++++++++
>  1 file changed, 34 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt

Acked-by: Rob Herring <robh@kernel.org>

Re: [PATCH v2 2/2] spi: spi-pic32: Add PIC32 SPI master driver

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 2696 bytes --]

Hi Purna,

[auto build test WARNING on robh/for-next]
[also build test WARNING on v4.5-rc6 next-20160304]
[cannot apply to spi/for-next]
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]

url:    https://github.com/0day-ci/linux/commits/Purna-Chandra-Mandal/dt-bindings-Add-bindings-for-PIC32-SPI-peripheral/20160304-214814
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux for-next
config: sparc64-allmodconfig (attached as .config)
reproduce:
        wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=sparc64 

All warnings (new ones prefixed by >>):

   In file included from include/linux/dmaengine.h:20:0,
                    from drivers/spi/spi-pic32.c:20:
   drivers/spi/spi-pic32.c: In function 'pic32_spi_dma_transfer':
>> drivers/spi/spi-pic32.c:392:18: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
       xfer->tx_buf, (void *)xfer->tx_dma,
                     ^
   include/linux/device.h:1286:41: note: in definition of macro 'dev_vdbg'
      dev_printk(KERN_DEBUG, dev, format, ##arg); \
                                            ^
   drivers/spi/spi-pic32.c:393:18: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
       xfer->rx_buf, (void *)xfer->rx_dma);
                     ^
   include/linux/device.h:1286:41: note: in definition of macro 'dev_vdbg'
      dev_printk(KERN_DEBUG, dev, format, ##arg); \
                                            ^

vim +392 drivers/spi/spi-pic32.c

   376			ret = -EINVAL;
   377			goto err_dma;
   378		}
   379	
   380		desc_tx = dmaengine_prep_slave_sg(master->dma_tx,
   381						  xfer->tx_sg.sgl,
   382						  xfer->tx_sg.nents,
   383						  DMA_TO_DEVICE,
   384						  DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
   385		if (!desc_tx) {
   386			ret = -EINVAL;
   387			goto err_dma;
   388		}
   389	
   390		dev_vdbg(&master->dev, "dma_xfer %p: len %u, tx %p(%p), rx %p(%p)\n",
   391			 xfer, xfer->len,
 > 392			 xfer->tx_buf, (void *)xfer->tx_dma,
   393			 xfer->rx_buf, (void *)xfer->rx_dma);
   394	
   395		/* Put callback on the RX transfer, that should finish last */
   396		desc_rx->callback = pic32_spi_dma_rx_notify;
   397		desc_rx->callback_param = pic32s;
   398	
   399		cookie = dmaengine_submit(desc_rx);
   400		ret = dma_submit_error(cookie);

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/octet-stream, Size: 44806 bytes --]

Re: [PATCH v2 2/2] spi: spi-pic32: Add PIC32 SPI master driver

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 2696 bytes --]

Hi Purna,

[auto build test WARNING on robh/for-next]
[also build test WARNING on v4.5-rc6 next-20160304]
[cannot apply to spi/for-next]
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]

url:    https://github.com/0day-ci/linux/commits/Purna-Chandra-Mandal/dt-bindings-Add-bindings-for-PIC32-SPI-peripheral/20160304-214814
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux for-next
config: sparc64-allmodconfig (attached as .config)
reproduce:
        wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=sparc64 

All warnings (new ones prefixed by >>):

   In file included from include/linux/dmaengine.h:20:0,
                    from drivers/spi/spi-pic32.c:20:
   drivers/spi/spi-pic32.c: In function 'pic32_spi_dma_transfer':
>> drivers/spi/spi-pic32.c:392:18: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
       xfer->tx_buf, (void *)xfer->tx_dma,
                     ^
   include/linux/device.h:1286:41: note: in definition of macro 'dev_vdbg'
      dev_printk(KERN_DEBUG, dev, format, ##arg); \
                                            ^
   drivers/spi/spi-pic32.c:393:18: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
       xfer->rx_buf, (void *)xfer->rx_dma);
                     ^
   include/linux/device.h:1286:41: note: in definition of macro 'dev_vdbg'
      dev_printk(KERN_DEBUG, dev, format, ##arg); \
                                            ^

vim +392 drivers/spi/spi-pic32.c

   376			ret = -EINVAL;
   377			goto err_dma;
   378		}
   379	
   380		desc_tx = dmaengine_prep_slave_sg(master->dma_tx,
   381						  xfer->tx_sg.sgl,
   382						  xfer->tx_sg.nents,
   383						  DMA_TO_DEVICE,
   384						  DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
   385		if (!desc_tx) {
   386			ret = -EINVAL;
   387			goto err_dma;
   388		}
   389	
   390		dev_vdbg(&master->dev, "dma_xfer %p: len %u, tx %p(%p), rx %p(%p)\n",
   391			 xfer, xfer->len,
 > 392			 xfer->tx_buf, (void *)xfer->tx_dma,
   393			 xfer->rx_buf, (void *)xfer->rx_dma);
   394	
   395		/* Put callback on the RX transfer, that should finish last */
   396		desc_rx->callback = pic32_spi_dma_rx_notify;
   397		desc_rx->callback_param = pic32s;
   398	
   399		cookie = dmaengine_submit(desc_rx);
   400		ret = dma_submit_error(cookie);

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/octet-stream, Size: 44806 bytes --]

Re: [PATCH v2 2/2] spi: spi-pic32: Add PIC32 SPI master driver

[Purna Chandra Mandal]

On 03/05/2016 09:10 AM, Mark Brown wrote:

> On Fri, Mar 04, 2016 at 07:14:42PM +0530, Purna Chandra Mandal wrote:
>> The PIC32 SPI driver is capable of performing SPI transfers
>> using PIO or external DMA engine. GPIO controlled /CS support
> I don't seem to have patch 1 in this series.

Sorry Mark.
I have missed adding you in CC. Please find it from:

https://lkml.org/lkml/2016/3/4/401

--Purna

Re: [PATCH v2 2/2] spi: spi-pic32: Add PIC32 SPI master driver

[Purna Chandra Mandal]

On 03/05/2016 09:10 AM, Mark Brown wrote:

> On Fri, Mar 04, 2016 at 07:14:42PM +0530, Purna Chandra Mandal wrote:
>> The PIC32 SPI driver is capable of performing SPI transfers
>> using PIO or external DMA engine. GPIO controlled /CS support
> I don't seem to have patch 1 in this series.

Sorry Mark.
I have missed adding you in CC. Please find it from:

https://lkml.org/lkml/2016/3/4/401

--Purna

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Re: [PATCH v2 2/2] spi: spi-pic32: Add PIC32 SPI master driver

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 248 bytes --]

On Sat, Mar 05, 2016 at 08:45:22PM +0530, Purna Chandra Mandal wrote:

> Sorry Mark.
> I have missed adding you in CC. Please find it from:

> https://lkml.org/lkml/2016/3/4/401

No, I can't review or apply patches from a web link - please resend.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 473 bytes --]

Re: [PATCH v2 2/2] spi: spi-pic32: Add PIC32 SPI master driver

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 248 bytes --]

On Sat, Mar 05, 2016 at 08:45:22PM +0530, Purna Chandra Mandal wrote:

> Sorry Mark.
> I have missed adding you in CC. Please find it from:

> https://lkml.org/lkml/2016/3/4/401

No, I can't review or apply patches from a web link - please resend.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 473 bytes --]

Applied "spi: pic32: Add bindings for PIC32 SPI peripheral" to the spi tree

[Mark Brown]

The patch

   spi: pic32: Add bindings for PIC32 SPI peripheral

has been applied to the spi tree at

   git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 120e8989ebac7c7c702e351046c20e9918912aca Mon Sep 17 00:00:00 2001
From: Purna Chandra Mandal <purna.mandal-UWL1GkI3JZL3oGB3hsPCZA@public.gmane.org>
Date: Fri, 1 Apr 2016 16:48:49 +0530
Subject: [PATCH] spi: pic32: Add bindings for PIC32 SPI peripheral

Document the devicetree bindings for the SPI peripheral found
on Microchip PIC32 class devices.

Signed-off-by: Purna Chandra Mandal <purna.mandal-UWL1GkI3JZL3oGB3hsPCZA@public.gmane.org>
Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Signed-off-by: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 .../bindings/spi/microchip,spi-pic32.txt           | 34 ++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt

diff --git a/Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt b/Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt
new file mode 100644
index 000000000000..79de379f4dc0
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/microchip,spi-pic32.txt
@@ -0,0 +1,34 @@
+Microchip PIC32 SPI Master controller
+
+Required properties:
+- compatible: Should be "microchip,pic32mzda-spi".
+- reg: Address and length of register space for the device.
+- interrupts: Should contain all three spi interrupts in sequence
+              of <fault-irq>, <receive-irq>, <transmit-irq>.
+- interrupt-names: Should be "fault", "rx", "tx" in order.
+- clocks: Phandle of the clock generating SPI clock on the bus.
+- clock-names: Should be "mck0".
+- cs-gpios: Specifies the gpio pins to be used for chipselects.
+            See: Documentation/devicetree/bindings/spi/spi-bus.txt
+
+Optional properties:
+- dmas: Two or more DMA channel specifiers following the convention outlined
+        in Documentation/devicetree/bindings/dma/dma.txt
+- dma-names: Names for the dma channels. There must be at least one channel
+             named "spi-tx" for transmit and named "spi-rx" for receive.
+
+Example:
+
+spi1: spi@1f821000 {
+        compatible = "microchip,pic32mzda-spi";
+        reg = <0x1f821000 0x200>;
+        interrupts = <109 IRQ_TYPE_LEVEL_HIGH>,
+                     <110 IRQ_TYPE_LEVEL_HIGH>,
+                     <111 IRQ_TYPE_LEVEL_HIGH>;
+        interrupt-names = "fault", "rx", "tx";
+        clocks = <&PBCLK2>;
+        clock-names = "mck0";
+        cs-gpios = <&gpio3 4 GPIO_ACTIVE_LOW>;
+        dmas = <&dma 134>, <&dma 135>;
+        dma-names = "spi-rx", "spi-tx";
+};
-- 
2.8.0.rc3

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