[PATCH v8 2/2] can: xilinx CAN controller support.

[Kedareswara rao Appana]

This patch adds xilinx CAN controller support.
This driver supports both ZYNQ CANPS and Soft IP
AXI CAN controller.

Signed-off-by: Kedareswara rao Appana <appanad@xxxxxxxxxx>
---
Changes for v8:
- call can_led_event only once in xcan_tx_interrupt();
- proceed with error handling if alloc_can_err_skb() failed in xcan_err_interrupt
- stop using 'cf' after netif_{rx|receive_skb}() calls;
- Modify the xcan_tx_interrupt loop logic as per Marc Suggestion;
Changes for v7:
- Updated the driver with review comments.
- Moved the driver bindings doc as a separte patch.
Changes for v6:
- Updated the driver with review comments.
- Used the clock names specified in the data sheet.
- Updated the devicetree bindings doc as per Rob suggestion.
Changes for v5:
- Updated the driver with the review comments.
- Remove the check for the tx fifo full interrupt condition
  form Tx interrupt routine as we are checking it in the _xmit
  routine.
- Clearing the txok interrupt in the tx interrupt routine for
  every Tx can frame.
Changes for v4:
- Added check for the tx fifo full interrupt condition in
Tx interrupt routine.
- Added be iohelper functions.
- Moved the clock enable/disable to probe/remove because of
  Added big endian support for AXI CAN controller case(reading
  a register during probe for that we need to enable clock).
Changes for v3:
- Updated the driver with the review comments.
- Modified the tranmit logic as per Marc suggestion.
- Enabling the clock when the interface is up to reduce the
  Power consumption.
Changes for v2:
- Updated with the review comments.
- Removed the unnecessary debug prints.
- include tx,rx fifo depths in ZYNQ CANPS case also.
---
 drivers/net/can/Kconfig      |    7 +
 drivers/net/can/Makefile     |    1 +
 drivers/net/can/xilinx_can.c | 1208 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1216 insertions(+), 0 deletions(-)
 create mode 100644 drivers/net/can/xilinx_can.c

diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig
index 9e7d95d..9049884 100644
--- a/drivers/net/can/Kconfig
+++ b/drivers/net/can/Kconfig
@@ -125,6 +125,13 @@ config CAN_GRCAN
 	  endian syntheses of the cores would need some modifications on
 	  the hardware level to work.
 
+config CAN_XILINXCAN
+	tristate "Xilinx CAN"
+	depends on ARCH_ZYNQ || MICROBLAZE || COMPILE_TEST
+	depends on COMMON_CLK && HAS_IOMEM
+	---help---
+	  Xilinx CAN driver. This driver supports both soft AXI CAN IP and
+	  Zynq CANPS IP.
 source "drivers/net/can/mscan/Kconfig"
 
 source "drivers/net/can/sja1000/Kconfig"
diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile
index c744039..0b8e11e 100644
--- a/drivers/net/can/Makefile
+++ b/drivers/net/can/Makefile
@@ -25,5 +25,6 @@ obj-$(CONFIG_CAN_JANZ_ICAN3)	+= janz-ican3.o
 obj-$(CONFIG_CAN_FLEXCAN)	+= flexcan.o
 obj-$(CONFIG_PCH_CAN)		+= pch_can.o
 obj-$(CONFIG_CAN_GRCAN)		+= grcan.o
+obj-$(CONFIG_CAN_XILINXCAN)	+= xilinx_can.o
 
 ccflags-$(CONFIG_CAN_DEBUG_DEVICES) := -DDEBUG
diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c
new file mode 100644
index 0000000..5e8b560
--- /dev/null
+++ b/drivers/net/can/xilinx_can.c
@@ -0,0 +1,1208 @@
+/* Xilinx CAN device driver
+ *
+ * Copyright (C) 2012 - 2014 Xilinx, Inc.
+ * Copyright (C) 2009 PetaLogix. All rights reserved.
+ *
+ * Description:
+ * This driver is developed for Axi CAN IP and for Zynq CANPS Controller.
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that 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/errno.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/skbuff.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/can/dev.h>
+#include <linux/can/error.h>
+#include <linux/can/led.h>
+
+#define DRIVER_NAME	"xilinx_can"
+
+/* CAN registers set */
+enum xcan_reg {
+	XCAN_SRR_OFFSET		= 0x00, /* Software reset */
+	XCAN_MSR_OFFSET		= 0x04, /* Mode select */
+	XCAN_BRPR_OFFSET	= 0x08, /* Baud rate prescaler */
+	XCAN_BTR_OFFSET		= 0x0C, /* Bit timing */
+	XCAN_ECR_OFFSET		= 0x10, /* Error counter */
+	XCAN_ESR_OFFSET		= 0x14, /* Error status */
+	XCAN_SR_OFFSET		= 0x18, /* Status */
+	XCAN_ISR_OFFSET		= 0x1C, /* Interrupt status */
+	XCAN_IER_OFFSET		= 0x20, /* Interrupt enable */
+	XCAN_ICR_OFFSET		= 0x24, /* Interrupt clear */
+	XCAN_TXFIFO_ID_OFFSET	= 0x30,/* TX FIFO ID */
+	XCAN_TXFIFO_DLC_OFFSET	= 0x34, /* TX FIFO DLC */
+	XCAN_TXFIFO_DW1_OFFSET	= 0x38, /* TX FIFO Data Word 1 */
+	XCAN_TXFIFO_DW2_OFFSET	= 0x3C, /* TX FIFO Data Word 2 */
+	XCAN_RXFIFO_ID_OFFSET	= 0x50, /* RX FIFO ID */
+	XCAN_RXFIFO_DLC_OFFSET	= 0x54, /* RX FIFO DLC */
+	XCAN_RXFIFO_DW1_OFFSET	= 0x58, /* RX FIFO Data Word 1 */
+	XCAN_RXFIFO_DW2_OFFSET	= 0x5C, /* RX FIFO Data Word 2 */
+};
+
+/* CAN register bit masks - XCAN_<REG>_<BIT>_MASK */
+#define XCAN_SRR_CEN_MASK		0x00000002 /* CAN enable */
+#define XCAN_SRR_RESET_MASK		0x00000001 /* Soft Reset the CAN core */
+#define XCAN_MSR_LBACK_MASK		0x00000002 /* Loop back mode select */
+#define XCAN_MSR_SLEEP_MASK		0x00000001 /* Sleep mode select */
+#define XCAN_BRPR_BRP_MASK		0x000000FF /* Baud rate prescaler */
+#define XCAN_BTR_SJW_MASK		0x00000180 /* Synchronous jump width */
+#define XCAN_BTR_TS2_MASK		0x00000070 /* Time segment 2 */
+#define XCAN_BTR_TS1_MASK		0x0000000F /* Time segment 1 */
+#define XCAN_ECR_REC_MASK		0x0000FF00 /* Receive error counter */
+#define XCAN_ECR_TEC_MASK		0x000000FF /* Transmit error counter */
+#define XCAN_ESR_ACKER_MASK		0x00000010 /* ACK error */
+#define XCAN_ESR_BERR_MASK		0x00000008 /* Bit error */
+#define XCAN_ESR_STER_MASK		0x00000004 /* Stuff error */
+#define XCAN_ESR_FMER_MASK		0x00000002 /* Form error */
+#define XCAN_ESR_CRCER_MASK		0x00000001 /* CRC error */
+#define XCAN_SR_TXFLL_MASK		0x00000400 /* TX FIFO is full */
+#define XCAN_SR_ESTAT_MASK		0x00000180 /* Error status */
+#define XCAN_SR_ERRWRN_MASK		0x00000040 /* Error warning */
+#define XCAN_SR_NORMAL_MASK		0x00000008 /* Normal mode */
+#define XCAN_SR_LBACK_MASK		0x00000002 /* Loop back mode */
+#define XCAN_SR_CONFIG_MASK		0x00000001 /* Configuration mode */
+#define XCAN_IXR_TXFEMP_MASK		0x00004000 /* TX FIFO Empty */
+#define XCAN_IXR_WKUP_MASK		0x00000800 /* Wake up interrupt */
+#define XCAN_IXR_SLP_MASK		0x00000400 /* Sleep interrupt */
+#define XCAN_IXR_BSOFF_MASK		0x00000200 /* Bus off interrupt */
+#define XCAN_IXR_ERROR_MASK		0x00000100 /* Error interrupt */
+#define XCAN_IXR_RXNEMP_MASK		0x00000080 /* RX FIFO NotEmpty intr */
+#define XCAN_IXR_RXOFLW_MASK		0x00000040 /* RX FIFO Overflow intr */
+#define XCAN_IXR_RXOK_MASK		0x00000010 /* Message received intr */
+#define XCAN_IXR_TXFLL_MASK		0x00000004 /* Tx FIFO Full intr */
+#define XCAN_IXR_TXOK_MASK		0x00000002 /* TX successful intr */
+#define XCAN_IXR_ARBLST_MASK		0x00000001 /* Arbitration lost intr */
+#define XCAN_IDR_ID1_MASK		0xFFE00000 /* Standard msg identifier */
+#define XCAN_IDR_SRR_MASK		0x00100000 /* Substitute remote TXreq */
+#define XCAN_IDR_IDE_MASK		0x00080000 /* Identifier extension */
+#define XCAN_IDR_ID2_MASK		0x0007FFFE /* Extended message ident */
+#define XCAN_IDR_RTR_MASK		0x00000001 /* Remote TX request */
+#define XCAN_DLCR_DLC_MASK		0xF0000000 /* Data length code */
+
+#define XCAN_INTR_ALL		(XCAN_IXR_TXOK_MASK | XCAN_IXR_BSOFF_MASK |\
+				 XCAN_IXR_WKUP_MASK | XCAN_IXR_SLP_MASK | \
+				 XCAN_IXR_RXNEMP_MASK | XCAN_IXR_ERROR_MASK | \
+				 XCAN_IXR_ARBLST_MASK | XCAN_IXR_RXOK_MASK)
+
+/* CAN register bit shift - XCAN_<REG>_<BIT>_SHIFT */
+#define XCAN_BTR_SJW_SHIFT		7  /* Synchronous jump width */
+#define XCAN_BTR_TS2_SHIFT		4  /* Time segment 2 */
+#define XCAN_IDR_ID1_SHIFT		21 /* Standard Messg Identifier */
+#define XCAN_IDR_ID2_SHIFT		1  /* Extended Message Identifier */
+#define XCAN_DLCR_DLC_SHIFT		28 /* Data length code */
+#define XCAN_ESR_REC_SHIFT		8  /* Rx Error Count */
+
+/* CAN frame length constants */
+#define XCAN_FRAME_MAX_DATA_LEN		8
+#define XCAN_TIMEOUT			(1 * HZ)
+
+/**
+ * struct xcan_priv - This definition define CAN driver instance
+ * @can:			CAN private data structure.
+ * @tx_head:			Tx CAN packets ready to send on the queue
+ * @tx_tail:			Tx CAN packets successfully sended on the queue
+ * @tx_max:			Maximum number packets the driver can send
+ * @napi:			NAPI structure
+ * @read_reg:			For reading data from CAN registers
+ * @write_reg:			For writing data to CAN registers
+ * @dev:			Network device data structure
+ * @reg_base:			Ioremapped address to registers
+ * @irq_flags:			For request_irq()
+ * @bus_clk:			Pointer to struct clk
+ * @can_clk:			Pointer to struct clk
+ */
+struct xcan_priv {
+	struct can_priv can;
+	unsigned int tx_head;
+	unsigned int tx_tail;
+	unsigned int tx_max;
+	struct napi_struct napi;
+	u32 (*read_reg)(const struct xcan_priv *priv, enum xcan_reg reg);
+	void (*write_reg)(const struct xcan_priv *priv, enum xcan_reg reg,
+			u32 val);
+	struct net_device *dev;
+	void __iomem *reg_base;
+	unsigned long irq_flags;
+	struct clk *bus_clk;
+	struct clk *can_clk;
+};
+
+/* CAN Bittiming constants as per Xilinx CAN specs */
+static const struct can_bittiming_const xcan_bittiming_const = {
+	.name = DRIVER_NAME,
+	.tseg1_min = 1,
+	.tseg1_max = 16,
+	.tseg2_min = 1,
+	.tseg2_max = 8,
+	.sjw_max = 4,
+	.brp_min = 1,
+	.brp_max = 256,
+	.brp_inc = 1,
+};
+
+/**
+ * xcan_write_reg_le - Write a value to the device register little endian
+ * @priv:	Driver private data structure
+ * @reg:	Register offset
+ * @val:	Value to write at the Register offset
+ *
+ * Write data to the paricular CAN register
+ */
+static void xcan_write_reg_le(const struct xcan_priv *priv, enum xcan_reg reg,
+			u32 val)
+{
+	iowrite32(val, priv->reg_base + reg);
+}
+
+/**
+ * xcan_read_reg_le - Read a value from the device register little endian
+ * @priv:	Driver private data structure
+ * @reg:	Register offset
+ *
+ * Read data from the particular CAN register
+ * Return: value read from the CAN register
+ */
+static u32 xcan_read_reg_le(const struct xcan_priv *priv, enum xcan_reg reg)
+{
+	return ioread32(priv->reg_base + reg);
+}
+
+/**
+ * xcan_write_reg_be - Write a value to the device register big endian
+ * @priv:	Driver private data structure
+ * @reg:	Register offset
+ * @val:	Value to write at the Register offset
+ *
+ * Write data to the paricular CAN register
+ */
+static void xcan_write_reg_be(const struct xcan_priv *priv, enum xcan_reg reg,
+			u32 val)
+{
+	iowrite32be(val, priv->reg_base + reg);
+}
+
+/**
+ * xcan_read_reg_be - Read a value from the device register big endian
+ * @priv:	Driver private data structure
+ * @reg:	Register offset
+ *
+ * Read data from the particular CAN register
+ * Return: value read from the CAN register
+ */
+static u32 xcan_read_reg_be(const struct xcan_priv *priv, enum xcan_reg reg)
+{
+	return ioread32be(priv->reg_base + reg);
+}
+
+/**
+ * set_reset_mode - Resets the CAN device mode
+ * @ndev:	Pointer to net_device structure
+ *
+ * This is the driver reset mode routine.The driver
+ * enters into configuration mode.
+ *
+ * Return: 0 on success and failure value on error
+ */
+static int set_reset_mode(struct net_device *ndev)
+{
+	struct xcan_priv *priv = netdev_priv(ndev);
+	unsigned long timeout;
+
+	priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_RESET_MASK);
+
+	timeout = jiffies + XCAN_TIMEOUT;
+	while (!(priv->read_reg(priv, XCAN_SR_OFFSET) & XCAN_SR_CONFIG_MASK)) {
+		if (time_after(jiffies, timeout)) {
+			netdev_warn(ndev, "timed out for config mode\n");
+			return -ETIMEDOUT;
+		}
+		usleep_range(500, 10000);
+	}
+
+	return 0;
+}
+
+/**
+ * xcan_set_bittiming - CAN set bit timing routine
+ * @ndev:	Pointer to net_device structure
+ *
+ * This is the driver set bittiming  routine.
+ * Return: 0 on success and failure value on error
+ */
+static int xcan_set_bittiming(struct net_device *ndev)
+{
+	struct xcan_priv *priv = netdev_priv(ndev);
+	struct can_bittiming *bt = &priv->can.bittiming;
+	u32 btr0, btr1;
+	u32 is_config_mode;
+
+	/* Check whether Xilinx CAN is in configuration mode.
+	 * It cannot set bit timing if Xilinx CAN is not in configuration mode.
+	 */
+	is_config_mode = priv->read_reg(priv, XCAN_SR_OFFSET) &
+				XCAN_SR_CONFIG_MASK;
+	if (!is_config_mode) {
+		netdev_alert(ndev,
+		     "BUG! Cannot set bittiming - CAN is not in config mode\n");
+		return -EPERM;
+	}
+
+	/* Setting Baud Rate prescalar value in BRPR Register */
+	btr0 = (bt->brp - 1);
+
+	/* Setting Time Segment 1 in BTR Register */
+	btr1 = (bt->prop_seg + bt->phase_seg1 - 1);
+
+	/* Setting Time Segment 2 in BTR Register */
+	btr1 |= (bt->phase_seg2 - 1) << XCAN_BTR_TS2_SHIFT;
+
+	/* Setting Synchronous jump width in BTR Register */
+	btr1 |= (bt->sjw - 1) << XCAN_BTR_SJW_SHIFT;
+
+	priv->write_reg(priv, XCAN_BRPR_OFFSET, btr0);
+	priv->write_reg(priv, XCAN_BTR_OFFSET, btr1);
+
+	netdev_dbg(ndev, "BRPR=0x%08x, BTR=0x%08x\n",
+			priv->read_reg(priv, XCAN_BRPR_OFFSET),
+			priv->read_reg(priv, XCAN_BTR_OFFSET));
+
+	return 0;
+}
+
+/**
+ * xcan_chip_start - This the drivers start routine
+ * @ndev:	Pointer to net_device structure
+ *
+ * This is the drivers start routine.
+ * Based on the State of the CAN device it puts
+ * the CAN device into a proper mode.
+ *
+ * Return: 0 on success and failure value on error
+ */
+static int xcan_chip_start(struct net_device *ndev)
+{
+	struct xcan_priv *priv = netdev_priv(ndev);
+	u32 err, reg_msr, reg_sr_mask;
+	unsigned long timeout;
+
+	/* Check if it is in reset mode */
+	err = set_reset_mode(ndev);
+	if (err < 0)
+		return err;
+
+	err = xcan_set_bittiming(ndev);
+	if (err < 0)
+		return err;
+
+	/* Enable interrupts */
+	priv->write_reg(priv, XCAN_IER_OFFSET, XCAN_INTR_ALL);
+
+	/* Check whether it is loopback mode or normal mode  */
+	if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {
+		reg_msr = XCAN_MSR_LBACK_MASK;
+		reg_sr_mask = XCAN_SR_LBACK_MASK;
+	} else {
+		reg_msr = 0x0;
+		reg_sr_mask = XCAN_SR_NORMAL_MASK;
+	}
+
+	priv->write_reg(priv, XCAN_MSR_OFFSET, reg_msr);
+	priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_CEN_MASK);
+
+	timeout = jiffies + XCAN_TIMEOUT;
+	while (!(priv->read_reg(priv, XCAN_SR_OFFSET) & reg_sr_mask)) {
+		if (time_after(jiffies, timeout)) {
+			netdev_warn(ndev,
+				"timed out for correct mode\n");
+			return -ETIMEDOUT;
+		}
+	}
+	netdev_dbg(ndev, "status:#x%08x\n",
+			priv->read_reg(priv, XCAN_SR_OFFSET));
+
+	priv->can.state = CAN_STATE_ERROR_ACTIVE;
+	return 0;
+}
+
+/**
+ * xcan_do_set_mode - This sets the mode of the driver
+ * @ndev:	Pointer to net_device structure
+ * @mode:	Tells the mode of the driver
+ *
+ * This check the drivers state and calls the
+ * the corresponding modes to set.
+ *
+ * Return: 0 on success and failure value on error
+ */
+static int xcan_do_set_mode(struct net_device *ndev, enum can_mode mode)
+{
+	int ret;
+
+	switch (mode) {
+	case CAN_MODE_START:
+		ret = xcan_chip_start(ndev);
+		if (ret < 0) {
+			netdev_err(ndev, "xcan_chip_start failed!\n");
+			return ret;
+		}
+		netif_wake_queue(ndev);
+		break;
+	default:
+		ret = -EOPNOTSUPP;
+		break;
+	}
+
+	return ret;
+}
+
+/**
+ * xcan_start_xmit - Starts the transmission
+ * @skb:	sk_buff pointer that contains data to be Txed
+ * @ndev:	Pointer to net_device structure
+ *
+ * This function is invoked from upper layers to initiate transmission. This
+ * function uses the next available free txbuff and populates their fields to
+ * start the transmission.
+ *
+ * Return: 0 on success and failure value on error
+ */
+static int xcan_start_xmit(struct sk_buff *skb, struct net_device *ndev)
+{
+	struct xcan_priv *priv = netdev_priv(ndev);
+	struct net_device_stats *stats = &ndev->stats;
+	struct can_frame *cf = (struct can_frame *)skb->data;
+	u32 id, dlc, data[2] = {0, 0};
+
+	if (can_dropped_invalid_skb(ndev, skb))
+		return NETDEV_TX_OK;
+
+	/* Check if the TX buffer is full */
+	if (unlikely(priv->read_reg(priv, XCAN_SR_OFFSET) &
+			XCAN_SR_TXFLL_MASK)) {
+		netif_stop_queue(ndev);
+		netdev_err(ndev, "BUG!, TX FIFO full when queue awake!\n");
+		return NETDEV_TX_BUSY;
+	}
+
+	/* Watch carefully on the bit sequence */
+	if (cf->can_id & CAN_EFF_FLAG) {
+		/* Extended CAN ID format */
+		id = ((cf->can_id & CAN_EFF_MASK) << XCAN_IDR_ID2_SHIFT) &
+			XCAN_IDR_ID2_MASK;
+		id |= (((cf->can_id & CAN_EFF_MASK) >>
+			(CAN_EFF_ID_BITS-CAN_SFF_ID_BITS)) <<
+			XCAN_IDR_ID1_SHIFT) & XCAN_IDR_ID1_MASK;
+
+		/* The substibute remote TX request bit should be "1"
+		 * for extended frames as in the Xilinx CAN datasheet
+		 */
+		id |= XCAN_IDR_IDE_MASK | XCAN_IDR_SRR_MASK;
+
+		if (cf->can_id & CAN_RTR_FLAG)
+			/* Extended frames remote TX request */
+			id |= XCAN_IDR_RTR_MASK;
+	} else {
+		/* Standard CAN ID format */
+		id = ((cf->can_id & CAN_SFF_MASK) << XCAN_IDR_ID1_SHIFT) &
+			XCAN_IDR_ID1_MASK;
+
+		if (cf->can_id & CAN_RTR_FLAG)
+			/* Standard frames remote TX request */
+			id |= XCAN_IDR_SRR_MASK;
+	}
+
+	dlc = cf->can_dlc << XCAN_DLCR_DLC_SHIFT;
+
+	if (cf->can_dlc > 0)
+		data[0] = be32_to_cpup((__be32 *)(cf->data + 0));
+	if (cf->can_dlc > 4)
+		data[1] = be32_to_cpup((__be32 *)(cf->data + 4));
+
+	can_put_echo_skb(skb, ndev, priv->tx_head % priv->tx_max);
+	priv->tx_head++;
+
+	/* Write the Frame to Xilinx CAN TX FIFO */
+	priv->write_reg(priv, XCAN_TXFIFO_ID_OFFSET, id);
+	/* If the CAN frame is RTR frame this write triggers tranmission */
+	priv->write_reg(priv, XCAN_TXFIFO_DLC_OFFSET, dlc);
+	if (!(cf->can_id & CAN_RTR_FLAG)) {
+		priv->write_reg(priv, XCAN_TXFIFO_DW1_OFFSET, data[0]);
+		/* If the CAN frame is Standard/Extended frame this
+		 * write triggers tranmission
+		 */
+		priv->write_reg(priv, XCAN_TXFIFO_DW2_OFFSET, data[1]);
+		stats->tx_bytes += cf->can_dlc;
+	}
+
+	/* Check if the TX buffer is full */
+	if ((priv->tx_head - priv->tx_tail) == priv->tx_max)
+		netif_stop_queue(ndev);
+
+	return NETDEV_TX_OK;
+}
+
+/**
+ * xcan_rx -  Is called from CAN isr to complete the received
+ *		frame  processing
+ * @ndev:	Pointer to net_device structure
+ *
+ * This function is invoked from the CAN isr(poll) to process the Rx frames. It
+ * does minimal processing and invokes "netif_receive_skb" to complete further
+ * processing.
+ * Return: 1 on success and 0 on failure.
+ */
+static int xcan_rx(struct net_device *ndev)
+{
+	struct xcan_priv *priv = netdev_priv(ndev);
+	struct net_device_stats *stats = &ndev->stats;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+	u32 id_xcan, dlc, data[2] = {0, 0};
+
+	skb = alloc_can_skb(ndev, &cf);
+	if (unlikely(!skb)) {
+		stats->rx_dropped++;
+		return 0;
+	}
+
+	/* Read a frame from Xilinx zynq CANPS */
+	id_xcan = priv->read_reg(priv, XCAN_RXFIFO_ID_OFFSET);
+	dlc = priv->read_reg(priv, XCAN_RXFIFO_DLC_OFFSET) >>
+				XCAN_DLCR_DLC_SHIFT;
+
+	/* Change Xilinx CAN data length format to socketCAN data format */
+	cf->can_dlc = get_can_dlc(dlc);
+
+	/* Change Xilinx CAN ID format to socketCAN ID format */
+	if (id_xcan & XCAN_IDR_IDE_MASK) {
+		/* The received frame is an Extended format frame */
+		cf->can_id = (id_xcan & XCAN_IDR_ID1_MASK) >> 3;
+		cf->can_id |= (id_xcan & XCAN_IDR_ID2_MASK) >>
+				XCAN_IDR_ID2_SHIFT;
+		cf->can_id |= CAN_EFF_FLAG;
+		if (id_xcan & XCAN_IDR_RTR_MASK)
+			cf->can_id |= CAN_RTR_FLAG;
+	} else {
+		/* The received frame is a standard format frame */
+		cf->can_id = (id_xcan & XCAN_IDR_ID1_MASK) >>
+				XCAN_IDR_ID1_SHIFT;
+		if (id_xcan & XCAN_IDR_SRR_MASK)
+			cf->can_id |= CAN_RTR_FLAG;
+	}
+
+	if (!(id_xcan & XCAN_IDR_SRR_MASK)) {
+		data[0] = priv->read_reg(priv, XCAN_RXFIFO_DW1_OFFSET);
+		data[1] = priv->read_reg(priv, XCAN_RXFIFO_DW2_OFFSET);
+
+		/* Change Xilinx CAN data format to socketCAN data format */
+		if (cf->can_dlc > 0)
+			*(__be32 *)(cf->data) = cpu_to_be32(data[0]);
+		if (cf->can_dlc > 4)
+			*(__be32 *)(cf->data + 4) = cpu_to_be32(data[1]);
+	}
+
+	stats->rx_bytes += cf->can_dlc;
+	stats->rx_packets++;
+	netif_receive_skb(skb);
+
+	return 1;
+}
+
+/**
+ * xcan_err_interrupt - error frame Isr
+ * @ndev:	net_device pointer
+ * @isr:	interrupt status register value
+ *
+ * This is the CAN error interrupt and it will
+ * check the the type of error and forward the error
+ * frame to upper layers.
+ */
+static void xcan_err_interrupt(struct net_device *ndev, u32 isr)
+{
+	struct xcan_priv *priv = netdev_priv(ndev);
+	struct net_device_stats *stats = &ndev->stats;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+	u32 err_status, status, txerr = 0, rxerr = 0;
+
+	skb = alloc_can_err_skb(ndev, &cf);
+
+	err_status = priv->read_reg(priv, XCAN_ESR_OFFSET);
+	priv->write_reg(priv, XCAN_ESR_OFFSET, err_status);
+	txerr = priv->read_reg(priv, XCAN_ECR_OFFSET) & XCAN_ECR_TEC_MASK;
+	rxerr = ((priv->read_reg(priv, XCAN_ECR_OFFSET) &
+			XCAN_ECR_REC_MASK) >> XCAN_ESR_REC_SHIFT);
+	status = priv->read_reg(priv, XCAN_SR_OFFSET);
+
+	if (isr & XCAN_IXR_BSOFF_MASK) {
+		priv->can.state = CAN_STATE_BUS_OFF;
+		priv->can.can_stats.bus_off++;
+		/* Leave device in Config Mode in bus-off state */
+		priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_RESET_MASK);
+		can_bus_off(ndev);
+		if (skb)
+			cf->can_id |= CAN_ERR_BUSOFF;
+	} else if ((status & XCAN_SR_ESTAT_MASK) == XCAN_SR_ESTAT_MASK) {
+		priv->can.state = CAN_STATE_ERROR_PASSIVE;
+		priv->can.can_stats.error_passive++;
+		if (skb) {
+			cf->can_id |= CAN_ERR_CRTL;
+			cf->data[1] = (rxerr > 127) ?
+					CAN_ERR_CRTL_RX_PASSIVE :
+					CAN_ERR_CRTL_TX_PASSIVE;
+			cf->data[6] = txerr;
+			cf->data[7] = rxerr;
+		}
+	} else if (status & XCAN_SR_ERRWRN_MASK) {
+		priv->can.state = CAN_STATE_ERROR_WARNING;
+		priv->can.can_stats.error_warning++;
+		if (skb) {
+			cf->can_id |= CAN_ERR_CRTL;
+			cf->data[1] |= (txerr > rxerr) ?
+					CAN_ERR_CRTL_TX_WARNING :
+					CAN_ERR_CRTL_RX_WARNING;
+			cf->data[6] = txerr;
+			cf->data[7] = rxerr;
+		}
+	}
+
+	/* Check for Arbitration lost interrupt */
+	if (isr & XCAN_IXR_ARBLST_MASK) {
+		priv->can.can_stats.arbitration_lost++;
+		if (skb) {
+			cf->can_id |= CAN_ERR_LOSTARB;
+			cf->data[0] = CAN_ERR_LOSTARB_UNSPEC;
+		}
+	}
+
+	/* Check for RX FIFO Overflow interrupt */
+	if (isr & XCAN_IXR_RXOFLW_MASK) {
+		stats->rx_over_errors++;
+		stats->rx_errors++;
+		priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_RESET_MASK);
+		if (skb) {
+			cf->can_id |= CAN_ERR_CRTL;
+			cf->data[1] |= CAN_ERR_CRTL_RX_OVERFLOW;
+		}
+	}
+
+	/* Check for error interrupt */
+	if (isr & XCAN_IXR_ERROR_MASK) {
+		if (skb) {
+			cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+			cf->data[2] |= CAN_ERR_PROT_UNSPEC;
+		}
+
+		/* Check for Ack error interrupt */
+		if (err_status & XCAN_ESR_ACKER_MASK) {
+			stats->tx_errors++;
+			if (skb) {
+				cf->can_id |= CAN_ERR_ACK;
+				cf->data[3] |= CAN_ERR_PROT_LOC_ACK;
+			}
+		}
+
+		/* Check for Bit error interrupt */
+		if (err_status & XCAN_ESR_BERR_MASK) {
+			stats->tx_errors++;
+			if (skb) {
+				cf->can_id |= CAN_ERR_PROT;
+				cf->data[2] = CAN_ERR_PROT_BIT;
+			}
+		}
+
+		/* Check for Stuff error interrupt */
+		if (err_status & XCAN_ESR_STER_MASK) {
+			stats->rx_errors++;
+			if (skb) {
+				cf->can_id |= CAN_ERR_PROT;
+				cf->data[2] = CAN_ERR_PROT_STUFF;
+			}
+		}
+
+		/* Check for Form error interrupt */
+		if (err_status & XCAN_ESR_FMER_MASK) {
+			stats->rx_errors++;
+			if (skb) {
+				cf->can_id |= CAN_ERR_PROT;
+				cf->data[2] = CAN_ERR_PROT_FORM;
+			}
+		}
+
+		/* Check for CRC error interrupt */
+		if (err_status & XCAN_ESR_CRCER_MASK) {
+			stats->rx_errors++;
+			if (skb) {
+				cf->can_id |= CAN_ERR_PROT;
+				cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ |
+						CAN_ERR_PROT_LOC_CRC_DEL;
+			}
+		}
+			priv->can.can_stats.bus_error++;
+	}
+
+	if (skb) {
+		stats->rx_packets++;
+		stats->rx_bytes += cf->can_dlc;
+		netif_rx(skb);
+	}
+
+	netdev_dbg(ndev, "%s: error status register:0x%x\n",
+			__func__, priv->read_reg(priv, XCAN_ESR_OFFSET));
+}
+
+/**
+ * xcan_state_interrupt - It will check the state of the CAN device
+ * @ndev:	net_device pointer
+ * @isr:	interrupt status register value
+ *
+ * This will checks the state of the CAN device
+ * and puts the device into appropriate state.
+ */
+static void xcan_state_interrupt(struct net_device *ndev, u32 isr)
+{
+	struct xcan_priv *priv = netdev_priv(ndev);
+
+	/* Check for Sleep interrupt if set put CAN device in sleep state */
+	if (isr & XCAN_IXR_SLP_MASK)
+		priv->can.state = CAN_STATE_SLEEPING;
+
+	/* Check for Wake up interrupt if set put CAN device in Active state */
+	if (isr & XCAN_IXR_WKUP_MASK)
+		priv->can.state = CAN_STATE_ERROR_ACTIVE;
+}
+
+/**
+ * xcan_rx_poll - Poll routine for rx packets (NAPI)
+ * @napi:	napi structure pointer
+ * @quota:	Max number of rx packets to be processed.
+ *
+ * This is the poll routine for rx part.
+ * It will process the packets maximux quota value.
+ *
+ * Return: number of packets received
+ */
+static int xcan_rx_poll(struct napi_struct *napi, int quota)
+{
+	struct net_device *ndev = napi->dev;
+	struct xcan_priv *priv = netdev_priv(ndev);
+	u32 isr, ier;
+	int work_done = 0;
+
+	isr = priv->read_reg(priv, XCAN_ISR_OFFSET);
+	while ((isr & XCAN_IXR_RXNEMP_MASK) && (work_done < quota)) {
+		if (isr & XCAN_IXR_RXOK_MASK) {
+			priv->write_reg(priv, XCAN_ICR_OFFSET,
+				XCAN_IXR_RXOK_MASK);
+			work_done += xcan_rx(ndev);
+		} else {
+			priv->write_reg(priv, XCAN_ICR_OFFSET,
+				XCAN_IXR_RXNEMP_MASK);
+			break;
+		}
+		priv->write_reg(priv, XCAN_ICR_OFFSET, XCAN_IXR_RXNEMP_MASK);
+		isr = priv->read_reg(priv, XCAN_ISR_OFFSET);
+	}
+
+	if (work_done)
+		can_led_event(ndev, CAN_LED_EVENT_RX);
+
+	if (work_done < quota) {
+		napi_complete(napi);
+		ier = priv->read_reg(priv, XCAN_IER_OFFSET);
+		ier |= (XCAN_IXR_RXOK_MASK | XCAN_IXR_RXNEMP_MASK);
+		priv->write_reg(priv, XCAN_IER_OFFSET, ier);
+	}
+	return work_done;
+}
+
+/**
+ * xcan_tx_interrupt - Tx Done Isr
+ * @ndev:	net_device pointer
+ * @isr:	Interrupt status register value
+ */
+static void xcan_tx_interrupt(struct net_device *ndev, u32 isr)
+{
+	struct xcan_priv *priv = netdev_priv(ndev);
+	struct net_device_stats *stats = &ndev->stats;
+
+	while ((priv->tx_head - priv->tx_tail > 0) &&
+			(isr & XCAN_IXR_TXOK_MASK)) {
+		priv->write_reg(priv, XCAN_ICR_OFFSET, XCAN_IXR_TXOK_MASK);
+		can_get_echo_skb(ndev, priv->tx_tail %
+					priv->tx_max);
+		priv->tx_tail++;
+		stats->tx_packets++;
+		isr = priv->read_reg(priv, XCAN_ISR_OFFSET);
+	}
+	can_led_event(ndev, CAN_LED_EVENT_TX);
+	netif_wake_queue(ndev);
+}
+
+/**
+ * xcan_interrupt - CAN Isr
+ * @irq:	irq number
+ * @dev_id:	device id poniter
+ *
+ * This is the xilinx CAN Isr. It checks for the type of interrupt
+ * and invokes the corresponding ISR.
+ *
+ * Return:
+ * IRQ_NONE - If CAN device is in sleep mode, IRQ_HANDLED otherwise
+ */
+static irqreturn_t xcan_interrupt(int irq, void *dev_id)
+{
+	struct net_device *ndev = (struct net_device *)dev_id;
+	struct xcan_priv *priv = netdev_priv(ndev);
+	u32 isr, ier;
+
+	/* Get the interrupt status from Xilinx CAN */
+	isr = priv->read_reg(priv, XCAN_ISR_OFFSET);
+	if (!isr)
+		return IRQ_NONE;
+
+	/* Check for the type of interrupt and Processing it */
+	if (isr & (XCAN_IXR_SLP_MASK | XCAN_IXR_WKUP_MASK)) {
+		priv->write_reg(priv, XCAN_ICR_OFFSET, (XCAN_IXR_SLP_MASK |
+				XCAN_IXR_WKUP_MASK));
+		xcan_state_interrupt(ndev, isr);
+	}
+
+	/* Check for Tx interrupt and Processing it */
+	if (isr & XCAN_IXR_TXOK_MASK)
+		xcan_tx_interrupt(ndev, isr);
+
+	/* Check for the type of error interrupt and Processing it */
+	if (isr & (XCAN_IXR_ERROR_MASK | XCAN_IXR_RXOFLW_MASK |
+			XCAN_IXR_BSOFF_MASK | XCAN_IXR_ARBLST_MASK)) {
+		priv->write_reg(priv, XCAN_ICR_OFFSET, (XCAN_IXR_ERROR_MASK |
+				XCAN_IXR_RXOFLW_MASK | XCAN_IXR_BSOFF_MASK |
+				XCAN_IXR_ARBLST_MASK));
+		xcan_err_interrupt(ndev, isr);
+	}
+
+	/* Check for the type of receive interrupt and Processing it */
+	if (isr & (XCAN_IXR_RXNEMP_MASK | XCAN_IXR_RXOK_MASK)) {
+		ier = priv->read_reg(priv, XCAN_IER_OFFSET);
+		ier &= ~(XCAN_IXR_RXNEMP_MASK | XCAN_IXR_RXOK_MASK);
+		priv->write_reg(priv, XCAN_IER_OFFSET, ier);
+		napi_schedule(&priv->napi);
+	}
+	return IRQ_HANDLED;
+}
+
+/**
+ * xcan_chip_stop - Driver stop routine
+ * @ndev:	Pointer to net_device structure
+ *
+ * This is the drivers stop routine. It will disable the
+ * interrupts and put the device into configuration mode.
+ */
+static void xcan_chip_stop(struct net_device *ndev)
+{
+	struct xcan_priv *priv = netdev_priv(ndev);
+	u32 ier;
+
+	/* Disable interrupts and leave the can in configuration mode */
+	ier = priv->read_reg(priv, XCAN_IER_OFFSET);
+	ier &= ~XCAN_INTR_ALL;
+	priv->write_reg(priv, XCAN_IER_OFFSET, ier);
+	priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_RESET_MASK);
+	priv->can.state = CAN_STATE_STOPPED;
+}
+
+/**
+ * xcan_open - Driver open routine
+ * @ndev:	Pointer to net_device structure
+ *
+ * This is the driver open routine.
+ * Return: 0 on success and failure value on error
+ */
+static int xcan_open(struct net_device *ndev)
+{
+	struct xcan_priv *priv = netdev_priv(ndev);
+	int ret;
+
+	ret = request_irq(ndev->irq, xcan_interrupt, priv->irq_flags,
+			ndev->name, ndev);
+	if (ret < 0) {
+		netdev_err(ndev, "irq allocation for CAN failed\n");
+		goto err;
+	}
+
+	ret = clk_prepare_enable(priv->can_clk);
+	if (ret) {
+		netdev_err(ndev, "unable to enable device clock\n");
+		goto err_irq;
+	}
+
+	ret = clk_prepare_enable(priv->bus_clk);
+	if (ret) {
+		netdev_err(ndev, "unable to enable bus clock\n");
+		goto err_can_clk;
+	}
+
+	/* Set chip into reset mode */
+	ret = set_reset_mode(ndev);
+	if (ret < 0) {
+		netdev_err(ndev, "mode resetting failed!\n");
+		goto err_bus_clk;
+	}
+
+	/* Common open */
+	ret = open_candev(ndev);
+	if (ret)
+		goto err_bus_clk;
+
+	ret = xcan_chip_start(ndev);
+	if (ret < 0) {
+		netdev_err(ndev, "xcan_chip_start failed!\n");
+		goto err_candev;
+	}
+
+	can_led_event(ndev, CAN_LED_EVENT_OPEN);
+	napi_enable(&priv->napi);
+	netif_start_queue(ndev);
+
+	return 0;
+
+err_candev:
+	close_candev(ndev);
+err_bus_clk:
+	clk_disable_unprepare(priv->bus_clk);
+err_can_clk:
+	clk_disable_unprepare(priv->can_clk);
+err_irq:
+	free_irq(ndev->irq, ndev);
+err:
+	return ret;
+}
+
+/**
+ * xcan_close - Driver close routine
+ * @ndev:	Pointer to net_device structure
+ *
+ * Return: 0 always
+ */
+static int xcan_close(struct net_device *ndev)
+{
+	struct xcan_priv *priv = netdev_priv(ndev);
+
+	netif_stop_queue(ndev);
+	napi_disable(&priv->napi);
+	xcan_chip_stop(ndev);
+	clk_disable_unprepare(priv->bus_clk);
+	clk_disable_unprepare(priv->can_clk);
+	free_irq(ndev->irq, ndev);
+	close_candev(ndev);
+
+	can_led_event(ndev, CAN_LED_EVENT_STOP);
+
+	return 0;
+}
+
+/**
+ * xcan_get_berr_counter - error counter routine
+ * @ndev:	Pointer to net_device structure
+ * @bec:	Pointer to can_berr_counter structure
+ *
+ * This is the driver error counter routine.
+ * Return: 0 on success and failure value on error
+ */
+static int xcan_get_berr_counter(const struct net_device *ndev,
+					struct can_berr_counter *bec)
+{
+	struct xcan_priv *priv = netdev_priv(ndev);
+	int ret;
+
+	ret = clk_prepare_enable(priv->can_clk);
+	if (ret)
+		goto err;
+
+	ret = clk_prepare_enable(priv->bus_clk);
+	if (ret)
+		goto err_clk;
+
+	bec->txerr = priv->read_reg(priv, XCAN_ECR_OFFSET) & XCAN_ECR_TEC_MASK;
+	bec->rxerr = ((priv->read_reg(priv, XCAN_ECR_OFFSET) &
+			XCAN_ECR_REC_MASK) >> XCAN_ESR_REC_SHIFT);
+
+	clk_disable_unprepare(priv->bus_clk);
+	clk_disable_unprepare(priv->can_clk);
+
+	return 0;
+
+err_clk:
+	clk_disable_unprepare(priv->can_clk);
+err:
+	return ret;
+}
+
+
+static const struct net_device_ops xcan_netdev_ops = {
+	.ndo_open	= xcan_open,
+	.ndo_stop	= xcan_close,
+	.ndo_start_xmit	= xcan_start_xmit,
+};
+
+/**
+ * xcan_suspend - Suspend method for the driver
+ * @dev:	Address of the platform_device structure
+ *
+ * Put the driver into low power mode.
+ * Return: 0 always
+ */
+static int __maybe_unused xcan_suspend(struct device *dev)
+{
+	struct platform_device *pdev = dev_get_drvdata(dev);
+	struct net_device *ndev = platform_get_drvdata(pdev);
+	struct xcan_priv *priv = netdev_priv(ndev);
+
+	if (netif_running(ndev)) {
+		netif_stop_queue(ndev);
+		netif_device_detach(ndev);
+	}
+
+	priv->write_reg(priv, XCAN_MSR_OFFSET, XCAN_MSR_SLEEP_MASK);
+	priv->can.state = CAN_STATE_SLEEPING;
+
+	clk_disable(priv->bus_clk);
+	clk_disable(priv->can_clk);
+
+	return 0;
+}
+
+/**
+ * xcan_resume - Resume from suspend
+ * @dev:	Address of the platformdevice structure
+ *
+ * Resume operation after suspend.
+ * Return: 0 on success and failure value on error
+ */
+static int __maybe_unused xcan_resume(struct device *dev)
+{
+	struct platform_device *pdev = dev_get_drvdata(dev);
+	struct net_device *ndev = platform_get_drvdata(pdev);
+	struct xcan_priv *priv = netdev_priv(ndev);
+	int ret;
+
+	ret = clk_enable(priv->bus_clk);
+	if (ret) {
+		dev_err(dev, "Cannot enable clock.\n");
+		return ret;
+	}
+	ret = clk_enable(priv->can_clk);
+	if (ret) {
+		dev_err(dev, "Cannot enable clock.\n");
+		clk_disable_unprepare(priv->bus_clk);
+		return ret;
+	}
+
+	priv->write_reg(priv, XCAN_MSR_OFFSET, 0);
+	priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_CEN_MASK);
+	priv->can.state = CAN_STATE_ERROR_ACTIVE;
+
+	if (netif_running(ndev)) {
+		netif_device_attach(ndev);
+		netif_start_queue(ndev);
+	}
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(xcan_dev_pm_ops, xcan_suspend, xcan_resume);
+
+/**
+ * xcan_probe - Platform registration call
+ * @pdev:	Handle to the platform device structure
+ *
+ * This function does all the memory allocation and registration for the CAN
+ * device.
+ *
+ * Return: 0 on success and failure value on error
+ */
+static int xcan_probe(struct platform_device *pdev)
+{
+	struct resource *res; /* IO mem resources */
+	struct net_device *ndev;
+	struct xcan_priv *priv;
+	void __iomem *addr;
+	int ret, rx_max, tx_max;
+
+	/* Get the virtual base address for the device */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	addr = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(addr)) {
+		ret = PTR_ERR(addr);
+		goto err;
+	}
+
+	ret = of_property_read_u32(pdev->dev.of_node, "tx-fifo-depth", &tx_max);
+	if (ret < 0)
+		goto err;
+
+	ret = of_property_read_u32(pdev->dev.of_node, "rx-fifo-depth", &rx_max);
+	if (ret < 0)
+		goto err;
+
+	/* Create a CAN device instance */
+	ndev = alloc_candev(sizeof(struct xcan_priv), tx_max);
+	if (!ndev)
+		return -ENOMEM;
+
+	priv = netdev_priv(ndev);
+	priv->dev = ndev;
+	priv->can.bittiming_const = &xcan_bittiming_const;
+	priv->can.do_set_mode = xcan_do_set_mode;
+	priv->can.do_get_berr_counter = xcan_get_berr_counter;
+	priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
+					CAN_CTRLMODE_BERR_REPORTING;
+	priv->reg_base = addr;
+	priv->tx_max = tx_max;
+
+	/* Get IRQ for the device */
+	ndev->irq = platform_get_irq(pdev, 0);
+	ndev->flags |= IFF_ECHO;	/* We support local echo */
+
+	platform_set_drvdata(pdev, ndev);
+	SET_NETDEV_DEV(ndev, &pdev->dev);
+	ndev->netdev_ops = &xcan_netdev_ops;
+
+	/* Getting the CAN can_clk info */
+	priv->can_clk = devm_clk_get(&pdev->dev, "can_clk");
+	if (IS_ERR(priv->can_clk)) {
+		dev_err(&pdev->dev, "Device clock not found.\n");
+		ret = PTR_ERR(priv->can_clk);
+		goto err_free;
+	}
+	/* Check for type of CAN device */
+	if (of_device_is_compatible(pdev->dev.of_node,
+				    "xlnx,zynq-can-1.0")) {
+		priv->bus_clk = devm_clk_get(&pdev->dev, "pclk");
+		if (IS_ERR(priv->bus_clk)) {
+			dev_err(&pdev->dev, "bus clock not found\n");
+			ret = PTR_ERR(priv->bus_clk);
+			goto err_free;
+		}
+	} else {
+		priv->bus_clk = devm_clk_get(&pdev->dev, "s_axi_aclk");
+		if (IS_ERR(priv->bus_clk)) {
+			dev_err(&pdev->dev, "bus clock not found\n");
+			ret = PTR_ERR(priv->bus_clk);
+			goto err_free;
+		}
+	}
+
+	ret = clk_prepare_enable(priv->can_clk);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to enable device clock\n");
+		goto err_free;
+	}
+
+	ret = clk_prepare_enable(priv->bus_clk);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to enable bus clock\n");
+		goto err_unprepare_disable_dev;
+	}
+
+	priv->write_reg = xcan_write_reg_le;
+	priv->read_reg = xcan_read_reg_le;
+
+	if (priv->read_reg(priv, XCAN_SR_OFFSET) != XCAN_SR_CONFIG_MASK) {
+		priv->write_reg = xcan_write_reg_be;
+		priv->read_reg = xcan_read_reg_be;
+	}
+
+	priv->can.clock.freq = clk_get_rate(priv->can_clk);
+
+	netif_napi_add(ndev, &priv->napi, xcan_rx_poll, rx_max);
+
+	ret = register_candev(ndev);
+	if (ret) {
+		dev_err(&pdev->dev, "fail to register failed (err=%d)\n", ret);
+		goto err_unprepare_disable_busclk;
+	}
+
+	devm_can_led_init(ndev);
+	clk_disable_unprepare(priv->bus_clk);
+	clk_disable_unprepare(priv->can_clk);
+	netdev_dbg(ndev, "reg_base=0x%p irq=%d clock=%d, tx fifo depth:%d\n",
+			priv->reg_base, ndev->irq, priv->can.clock.freq,
+			priv->tx_max);
+
+	return 0;
+
+err_unprepare_disable_busclk:
+	clk_disable_unprepare(priv->bus_clk);
+err_unprepare_disable_dev:
+	clk_disable_unprepare(priv->can_clk);
+err_free:
+	free_candev(ndev);
+err:
+	return ret;
+}
+
+/**
+ * xcan_remove - Unregister the device after releasing the resources
+ * @pdev:	Handle to the platform device structure
+ *
+ * This function frees all the resources allocated to the device.
+ * Return: 0 always
+ */
+static int xcan_remove(struct platform_device *pdev)
+{
+	struct net_device *ndev = platform_get_drvdata(pdev);
+	struct xcan_priv *priv = netdev_priv(ndev);
+
+	if (set_reset_mode(ndev) < 0)
+		netdev_err(ndev, "mode resetting failed!\n");
+
+	unregister_candev(ndev);
+	netif_napi_del(&priv->napi);
+	free_candev(ndev);
+
+	return 0;
+}
+
+/* Match table for OF platform binding */
+static struct of_device_id xcan_of_match[] = {
+	{ .compatible = "xlnx,zynq-can-1.0", },
+	{ .compatible = "xlnx,axi-can-1.00.a", },
+	{ /* end of list */ },
+};
+MODULE_DEVICE_TABLE(of, xcan_of_match);
+
+static struct platform_driver xcan_driver = {
+	.probe = xcan_probe,
+	.remove	= xcan_remove,
+	.driver	= {
+		.owner = THIS_MODULE,
+		.name = DRIVER_NAME,
+		.pm = &xcan_dev_pm_ops,
+		.of_match_table	= xcan_of_match,
+	},
+};
+
+module_platform_driver(xcan_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Xilinx Inc");
+MODULE_DESCRIPTION("Xilinx CAN interface");
-- 
1.7.4


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