Subject: Re: [PATCH 3/4] powerpc/p1010: FlexCAN Controller for of_ type

From: Marc Kleine-Budde <[email-masked]>
Date: Mon, 08 Aug 2011 17:21:15 +0200

On 08/08/2011 05:00 PM, Bhaskar Upadhaya wrote:
> Provide FlexCAN support for Freescale P1010 SoC.
> Modify the existing FlexCAN, so as to support the of_type approach on
> P1010(power architecture based)SoC.
> 
> FlexCAN is a communication controller implementing the CAN protocol according
> to the CAN 2.0B protocol specification.
> This controller is available on Freescale P1010 platform.
> Signed-off-by: Bhaskar Upadhaya <[email-masked]>

NACK - your patch does more than the description states (debug code).
Further you still add bugs to the driver. I've send you patches to fix them.

Marc

> ---
> Based on git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6.git
>  Branch master
> 
>  drivers/net/can/Kconfig         |    8 +-
>  drivers/net/can/Makefile        |    4 +-
>  drivers/net/can/flexcan.c       |  162 ++++++++++++------------
>  drivers/net/can/flexcan_iface.c |  261 +++++++++++++++++++++++++++++++++++++++
>  4 files changed, 349 insertions(+), 86 deletions(-)
>  create mode 100644 drivers/net/can/flexcan_iface.c
> 
> diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig
> index f6c98fb..882da54 100644
> --- a/drivers/net/can/Kconfig
> +++ b/drivers/net/can/Kconfig
> @@ -98,9 +98,12 @@ config HAVE_CAN_FLEXCAN
>  
>  config CAN_FLEXCAN
>  	tristate "Support for Freescale FLEXCAN based chips"
> -	depends on CAN_DEV && HAVE_CAN_FLEXCAN
> +	depends on CAN_DEV && (!ARM || HAVE_CAN_FLEXCAN)
> +	select PPC_CLOCK
>  	---help---
> -	  Say Y here if you want to support for Freescale FlexCAN.
> +	  Say Y here if you want support for Freescale FlexCAN.
> +	  Flexcan Module is implementing the CAN Protocol
> +	  version 2.0
>  
>  config PCH_CAN
>  	tristate "PCH CAN"
> @@ -123,6 +126,7 @@ source "drivers/net/can/softing/Kconfig"
>  config CAN_DEBUG_DEVICES
>  	bool "CAN devices debugging messages"
>  	depends on CAN
> +	default N
>  	---help---
>  	  Say Y here if you want the CAN device drivers to produce a bunch of
>  	  debug messages to the system log.  Select this if you are having
> diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile
> index 24ebfe8..4965e6f 100644
> --- a/drivers/net/can/Makefile
> +++ b/drivers/net/can/Makefile
> @@ -19,7 +19,9 @@ obj-$(CONFIG_CAN_TI_HECC)	+= ti_hecc.o
>  obj-$(CONFIG_CAN_MCP251X)	+= mcp251x.o
>  obj-$(CONFIG_CAN_BFIN)		+= bfin_can.o
>  obj-$(CONFIG_CAN_JANZ_ICAN3)	+= janz-ican3.o
> -obj-$(CONFIG_CAN_FLEXCAN)	+= flexcan.o
> +obj-$(CONFIG_CAN_FLEXCAN)	+= flexcan_driver.o
> +flexcan_driver-objs := flexcan.o \
> +		flexcan_iface.o
>  obj-$(CONFIG_PCH_CAN)		+= pch_can.o
>  
>  ccflags-$(CONFIG_CAN_DEBUG_DEVICES) := -DDEBUG
> diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
> index a24aa12..1c1af24 100644
> --- a/drivers/net/can/flexcan.c
> +++ b/drivers/net/can/flexcan.c
> @@ -22,10 +22,8 @@
>  
>  #include <linux/netdevice.h>
>  #include <linux/can.h>
> -#include <linux/can/dev.h>
>  #include <linux/can/error.h>
>  #include <linux/can/platform/flexcan.h>
> -#include <linux/clk.h>
>  #include <linux/delay.h>
>  #include <linux/if_arp.h>
>  #include <linux/if_ether.h>
> @@ -34,11 +32,6 @@
>  #include <linux/kernel.h>
>  #include <linux/list.h>
>  #include <linux/module.h>
> -#include <linux/platform_device.h>
> -
> -#include <mach/clock.h>
> -
> -#define DRV_NAME			"flexcan"
>  
>  /* 8 for RX fifo and 2 error handling */
>  #define FLEXCAN_NAPI_WEIGHT		(8 + 2)
> @@ -167,19 +160,6 @@ struct flexcan_regs {
>  	struct flexcan_mb cantxfg[64];
>  };
>  
> -struct flexcan_priv {
> -	struct can_priv can;
> -	struct net_device *dev;
> -	struct napi_struct napi;
> -
> -	void __iomem *base;
> -	u32 reg_esr;
> -	u32 reg_ctrl_default;
> -
> -	struct clk *clk;
> -	struct flexcan_platform_data *pdata;
> -};
> -
>  static struct can_bittiming_const flexcan_bittiming_const = {
>  	.name = DRV_NAME,
>  	.tseg1_min = 4,
> @@ -229,9 +209,10 @@ static inline void flexcan_chip_enable(struct flexcan_priv *priv)
>  	struct flexcan_regs __iomem *regs = priv->base;
>  	u32 reg;
>  
> -	reg = readl(&regs->mcr);
> +	reg = flexcan_read(&regs->mcr);
> +
>  	reg &= ~FLEXCAN_MCR_MDIS;
> -	writel(reg, &regs->mcr);
> +	flexcan_write(reg, &regs->mcr);
>  
>  	udelay(10);
>  }
> @@ -248,9 +229,10 @@ static inline void flexcan_chip_disable(struct flexcan_priv *priv)
>  	struct flexcan_regs __iomem *regs = priv->base;
>  	u32 reg;
>  
> -	reg = readl(&regs->mcr);
> +	reg = flexcan_read(&regs->mcr);
> +
>  	reg |= FLEXCAN_MCR_MDIS;
> -	writel(reg, &regs->mcr);
> +	flexcan_write(reg, &regs->mcr);
>  }
>  
>  /**
> @@ -266,9 +248,9 @@ static int flexcan_get_berr_counter(const struct net_device *dev,
>  {
>  	const struct flexcan_priv *priv = netdev_priv(dev);
>  	struct flexcan_regs __iomem *regs = priv->base;
> -	u32 reg = readl(&regs->ecr);
>  
> -	bec->txerr = (reg >> 0) & 0xff;
> +	u32 reg = flexcan_read(&regs->ecr);
> +	bec->txerr = reg & 0xff;
>  	bec->rxerr = (reg >> 8) & 0xff;
>  
>  	return 0;
> @@ -294,6 +276,7 @@ static int flexcan_start_xmit(struct sk_buff *skb, struct net_device *dev)
>  	u32 can_id;
>  	u32 ctrl = FLEXCAN_MB_CNT_CODE(0xc) | (cf->can_dlc << 16);
>  
> +	flexcan_reg_dump(dev);
>  	if (can_dropped_invalid_skb(dev, skb))
>  		return NETDEV_TX_OK;
>  
> @@ -311,21 +294,24 @@ static int flexcan_start_xmit(struct sk_buff *skb, struct net_device *dev)
>  
>  	if (cf->can_dlc > 0) {
>  		u32 data = be32_to_cpup((__be32 *)&cf->data[0]);
> -		writel(data, &regs->cantxfg[FLEXCAN_TX_BUF_ID].data[0]);
> +		flexcan_write(data,
> +			&regs->cantxfg[FLEXCAN_TX_BUF_ID].data[0]);
>  	}
>  	if (cf->can_dlc > 3) {
>  		u32 data = be32_to_cpup((__be32 *)&cf->data[4]);
> -		writel(data, &regs->cantxfg[FLEXCAN_TX_BUF_ID].data[1]);
> +		flexcan_write(data,
> +			&regs->cantxfg[FLEXCAN_TX_BUF_ID].data[1]);
>  	}
>  
> -	writel(can_id, &regs->cantxfg[FLEXCAN_TX_BUF_ID].can_id);
> -	writel(ctrl, &regs->cantxfg[FLEXCAN_TX_BUF_ID].can_ctrl);
> +	flexcan_write(can_id, &regs->cantxfg[FLEXCAN_TX_BUF_ID].can_id);
> +	flexcan_write(ctrl, &regs->cantxfg[FLEXCAN_TX_BUF_ID].can_ctrl);
>  
>  	kfree_skb(skb);
>  
>  	/* tx_packets is incremented in flexcan_irq */
>  	stats->tx_bytes += cf->can_dlc;
>  
> +	flexcan_reg_dump(dev);
>  	return NETDEV_TX_OK;
>  }
>  
> @@ -440,7 +426,8 @@ static void do_state(struct net_device *dev,
>  				CAN_ERR_CRTL_TX_WARNING :
>  				CAN_ERR_CRTL_RX_WARNING;
>  		}
> -	case CAN_STATE_ERROR_WARNING:	/* fallthrough */
> +		/* fallthrough */
> +	case CAN_STATE_ERROR_WARNING:
>  		/*
>  		 * from: ERROR_ACTIVE, ERROR_WARNING
>  		 * to  : ERROR_PASSIVE, BUS_OFF
> @@ -536,8 +523,8 @@ static void flexcan_read_fifo(const struct net_device *dev,
>  	struct flexcan_mb __iomem *mb = &regs->cantxfg[0];
>  	u32 reg_ctrl, reg_id;
>  
> -	reg_ctrl = readl(&mb->can_ctrl);
> -	reg_id = readl(&mb->can_id);
> +	reg_ctrl = flexcan_read(&mb->can_ctrl);
> +	reg_id = flexcan_read(&mb->can_id);
>  	if (reg_ctrl & FLEXCAN_MB_CNT_IDE)
>  		cf->can_id = ((reg_id >> 0) & CAN_EFF_MASK) | CAN_EFF_FLAG;
>  	else
> @@ -547,12 +534,13 @@ static void flexcan_read_fifo(const struct net_device *dev,
>  		cf->can_id |= CAN_RTR_FLAG;
>  	cf->can_dlc = get_can_dlc((reg_ctrl >> 16) & 0xf);
>  
> -	*(__be32 *)(cf->data + 0) = cpu_to_be32(readl(&mb->data[0]));
> -	*(__be32 *)(cf->data + 4) = cpu_to_be32(readl(&mb->data[1]));
> +	*(__be32 *) (&cf->data[0]) =
> +	    cpu_to_be32(flexcan_read(&mb->data[0]));
> +	*(__be32 *) (&cf->data[4]) =
> +	    cpu_to_be32(flexcan_read(&mb->data[1]));
>  
>  	/* mark as read */
> -	writel(FLEXCAN_IFLAG_RX_FIFO_AVAILABLE, &regs->iflag1);
> -	readl(&regs->timer);
> +	flexcan_write(FLEXCAN_IFLAG_RX_FIFO_AVAILABLE, &regs->iflag1);
>  }
>  
>  static int flexcan_read_frame(struct net_device *dev)
> @@ -596,17 +584,17 @@ static int flexcan_poll(struct napi_struct *napi, int quota)
>  	 * The error bits are cleared on read,
>  	 * use saved value from irq handler.
>  	 */
> -	reg_esr = readl(&regs->esr) | priv->reg_esr;
> +	reg_esr = flexcan_read(&regs->esr) | priv->reg_esr;
>  
>  	/* handle state changes */
>  	work_done += flexcan_poll_state(dev, reg_esr);
>  
>  	/* handle RX-FIFO */
> -	reg_iflag1 = readl(&regs->iflag1);
> -	while (reg_iflag1 & FLEXCAN_IFLAG_RX_FIFO_AVAILABLE &&
> -	       work_done < quota) {
> +	reg_iflag1 = flexcan_read(&regs->iflag1);
> +	while ((reg_iflag1 & FLEXCAN_IFLAG_RX_FIFO_AVAILABLE) &&
> +	       (work_done < quota)) {
>  		work_done += flexcan_read_frame(dev);
> -		reg_iflag1 = readl(&regs->iflag1);
> +		reg_iflag1 = flexcan_read(&regs->iflag1);
>  	}
>  
>  	/* report bus errors */
> @@ -616,8 +604,8 @@ static int flexcan_poll(struct napi_struct *napi, int quota)
>  	if (work_done < quota) {
>  		napi_complete(napi);
>  		/* enable IRQs */
> -		writel(FLEXCAN_IFLAG_DEFAULT, &regs->imask1);
> -		writel(priv->reg_ctrl_default, &regs->ctrl);
> +		flexcan_write(FLEXCAN_IFLAG_DEFAULT, &regs->imask1);
> +		flexcan_write(priv->reg_ctrl_default, &regs->ctrl);
>  	}
>  
>  	return work_done;
> @@ -641,9 +629,10 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id)
>  	struct flexcan_regs __iomem *regs = priv->base;
>  	u32 reg_iflag1, reg_esr;
>  
> -	reg_iflag1 = readl(&regs->iflag1);
> -	reg_esr = readl(&regs->esr);
> -	writel(FLEXCAN_ESR_ERR_INT, &regs->esr);	/* ACK err IRQ */
> +	flexcan_reg_dump(dev);
> +	reg_iflag1 = flexcan_read(&regs->iflag1);
> +	reg_esr = flexcan_read(&regs->esr);
> +	flexcan_write(FLEXCAN_ESR_ERR_INT, &regs->esr);/* ACK err IRQ */
>  
>  	/*
>  	 * schedule NAPI in case of:
> @@ -659,16 +648,17 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id)
>  		 * save them for later use.
>  		 */
>  		priv->reg_esr = reg_esr & FLEXCAN_ESR_ERR_BUS;
> -		writel(FLEXCAN_IFLAG_DEFAULT & ~FLEXCAN_IFLAG_RX_FIFO_AVAILABLE,
> -		       &regs->imask1);
> -		writel(priv->reg_ctrl_default & ~FLEXCAN_CTRL_ERR_ALL,
> -		       &regs->ctrl);
> +		flexcan_write(FLEXCAN_IFLAG_DEFAULT &
> +			~FLEXCAN_IFLAG_RX_FIFO_AVAILABLE, &regs->imask1);
> +		flexcan_write(priv->reg_ctrl_default &
> +			~FLEXCAN_CTRL_ERR_ALL, &regs->ctrl);
>  		napi_schedule(&priv->napi);
>  	}
>  
>  	/* FIFO overflow */
>  	if (reg_iflag1 & FLEXCAN_IFLAG_RX_FIFO_OVERFLOW) {
> -		writel(FLEXCAN_IFLAG_RX_FIFO_OVERFLOW, &regs->iflag1);
> +		flexcan_write(FLEXCAN_IFLAG_RX_FIFO_OVERFLOW,
> +			&regs->iflag1);
>  		dev->stats.rx_over_errors++;
>  		dev->stats.rx_errors++;
>  	}
> @@ -677,10 +667,11 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id)
>  	if (reg_iflag1 & (1 << FLEXCAN_TX_BUF_ID)) {
>  		/* tx_bytes is incremented in flexcan_start_xmit */
>  		stats->tx_packets++;
> -		writel((1 << FLEXCAN_TX_BUF_ID), &regs->iflag1);
> +		flexcan_write((1 << FLEXCAN_TX_BUF_ID), &regs->iflag1);
>  		netif_wake_queue(dev);
>  	}
>  
> +	flexcan_reg_dump(dev);
>  	return IRQ_HANDLED;
>  }
>  
> @@ -698,7 +689,7 @@ static void flexcan_set_bittiming(struct net_device *dev)
>  	struct flexcan_regs __iomem *regs = priv->base;
>  	u32 reg;
>  
> -	reg = readl(&regs->ctrl);
> +	reg = flexcan_read(&regs->ctrl);
>  	reg &= ~(FLEXCAN_CTRL_PRESDIV(0xff) |
>  		 FLEXCAN_CTRL_RJW(0x3) |
>  		 FLEXCAN_CTRL_PSEG1(0x7) |
> @@ -722,11 +713,11 @@ static void flexcan_set_bittiming(struct net_device *dev)
>  		reg |= FLEXCAN_CTRL_SMP;
>  
>  	dev_info(dev->dev.parent, "writing ctrl=0x%08x\n", reg);
> -	writel(reg, &regs->ctrl);
> +	flexcan_write(reg, &regs->ctrl);
>  
>  	/* print chip status */
>  	dev_dbg(dev->dev.parent, "%s: mcr=0x%08x ctrl=0x%08x\n", __func__,
> -		readl(&regs->mcr), readl(&regs->ctrl));
> +		flexcan_read(&regs->mcr), flexcan_read(&regs->ctrl));
>  }
>  
>  /**
> @@ -751,10 +742,10 @@ static int flexcan_chip_start(struct net_device *dev)
>  	flexcan_chip_enable(priv);
>  
>  	/* soft reset */
> -	writel(FLEXCAN_MCR_SOFTRST, &regs->mcr);
> +	flexcan_write(FLEXCAN_MCR_SOFTRST, &regs->mcr);
>  	udelay(10);
>  
> -	reg_mcr = readl(&regs->mcr);
> +	reg_mcr = flexcan_read(&regs->mcr);
>  	if (reg_mcr & FLEXCAN_MCR_SOFTRST) {
>  		dev_err(dev->dev.parent,
>  			"Failed to softreset can module (mcr=0x%08x)\n",
> @@ -776,12 +767,12 @@ static int flexcan_chip_start(struct net_device *dev)
>  	 * choose format C
>  	 *
>  	 */
> -	reg_mcr = readl(&regs->mcr);
> +	reg_mcr = flexcan_read(&regs->mcr);
>  	reg_mcr |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_FEN | FLEXCAN_MCR_HALT |
>  		FLEXCAN_MCR_SUPV | FLEXCAN_MCR_WRN_EN |
>  		FLEXCAN_MCR_IDAM_C;
>  	dev_dbg(dev->dev.parent, "%s: writing mcr=0x%08x", __func__, reg_mcr);
> -	writel(reg_mcr, &regs->mcr);
> +	flexcan_write(reg_mcr, &regs->mcr);
>  
>  	/*
>  	 * CTRL
> @@ -799,7 +790,7 @@ static int flexcan_chip_start(struct net_device *dev)
>  	 * (FLEXCAN_CTRL_ERR_MSK), too. Otherwise we don't get any
>  	 * warning or bus passive interrupts.
>  	 */
> -	reg_ctrl = readl(&regs->ctrl);
> +	reg_ctrl = flexcan_read(&regs->ctrl);
>  	reg_ctrl &= ~FLEXCAN_CTRL_TSYN;
>  	reg_ctrl |= FLEXCAN_CTRL_BOFF_REC | FLEXCAN_CTRL_LBUF |
>  		FLEXCAN_CTRL_ERR_STATE | FLEXCAN_CTRL_ERR_MSK;
> @@ -807,38 +798,40 @@ static int flexcan_chip_start(struct net_device *dev)
>  	/* save for later use */
>  	priv->reg_ctrl_default = reg_ctrl;
>  	dev_dbg(dev->dev.parent, "%s: writing ctrl=0x%08x", __func__, reg_ctrl);
> -	writel(reg_ctrl, &regs->ctrl);
> +	flexcan_write(reg_ctrl, &regs->ctrl);
>  
>  	for (i = 0; i < ARRAY_SIZE(regs->cantxfg); i++) {
> -		writel(0, &regs->cantxfg[i].can_ctrl);
> -		writel(0, &regs->cantxfg[i].can_id);
> -		writel(0, &regs->cantxfg[i].data[0]);
> -		writel(0, &regs->cantxfg[i].data[1]);
> +		flexcan_write(0, &regs->cantxfg[i].can_ctrl);
> +		flexcan_write(0, &regs->cantxfg[i].can_id);
> +		flexcan_write(0, &regs->cantxfg[i].data[0]);
> +		flexcan_write(0, &regs->cantxfg[i].data[1]);
>  
>  		/* put MB into rx queue */
> -		writel(FLEXCAN_MB_CNT_CODE(0x4), &regs->cantxfg[i].can_ctrl);
> +		flexcan_write(FLEXCAN_MB_CNT_CODE(0x4),
> +			&regs->cantxfg[i].can_ctrl);
>  	}
>  
>  	/* acceptance mask/acceptance code (accept everything) */
> -	writel(0x0, &regs->rxgmask);
> -	writel(0x0, &regs->rx14mask);
> -	writel(0x0, &regs->rx15mask);
> +	flexcan_write(0x0, &regs->rxgmask);
> +	flexcan_write(0x0, &regs->rx14mask);
> +	flexcan_write(0x0, &regs->rx15mask);
>  
>  	flexcan_transceiver_switch(priv, 1);
>  
>  	/* synchronize with the can bus */
> -	reg_mcr = readl(&regs->mcr);
> +	reg_mcr = flexcan_read(&regs->mcr);
>  	reg_mcr &= ~FLEXCAN_MCR_HALT;
> -	writel(reg_mcr, &regs->mcr);
> +	flexcan_write(reg_mcr, &regs->mcr);
>  
>  	priv->can.state = CAN_STATE_ERROR_ACTIVE;
>  
>  	/* enable FIFO interrupts */
> -	writel(FLEXCAN_IFLAG_DEFAULT, &regs->imask1);
> +	flexcan_write(FLEXCAN_IFLAG_DEFAULT, &regs->imask1);
>  
>  	/* print chip status */
>  	dev_dbg(dev->dev.parent, "%s: reading mcr=0x%08x ctrl=0x%08x\n",
> -		__func__, readl(&regs->mcr), readl(&regs->ctrl));
> +		__func__, flexcan_read(&regs->mcr),
> +			flexcan_read(&regs->ctrl));
>  
>  	return 0;
>  
> @@ -860,12 +853,12 @@ static void flexcan_chip_stop(struct net_device *dev)
>  	u32 reg;
>  
>  	/* Disable all interrupts */
> -	writel(0, &regs->imask1);
> +	flexcan_write(0, &regs->imask1);
>  
>  	/* Disable + halt module */
> -	reg = readl(&regs->mcr);
> +	reg = flexcan_read(&regs->mcr);
>  	reg |= FLEXCAN_MCR_MDIS | FLEXCAN_MCR_HALT;
> -	writel(reg, &regs->mcr);
> +	flexcan_write(reg, &regs->mcr);
>  
>  	flexcan_transceiver_switch(priv, 0);
>  	priv->can.state = CAN_STATE_STOPPED;
> @@ -935,6 +928,8 @@ static int flexcan_set_mode(struct net_device *dev, enum can_mode mode)
>  		break;
>  
>  	default:
> +		dev_dbg(dev->dev.parent, "Setting flexcan mode(%d) in func %s in line"
> +					"%d \r\n", mode, __func__, __LINE__);
>  		return -EOPNOTSUPP;
>  	}
>  
> @@ -957,24 +952,24 @@ static int __devinit register_flexcandev(struct net_device *dev)
>  
>  	/* select "bus clock", chip must be disabled */
>  	flexcan_chip_disable(priv);
> -	reg = readl(&regs->ctrl);
> +	reg = flexcan_read(&regs->ctrl);
>  	reg |= FLEXCAN_CTRL_CLK_SRC;
> -	writel(reg, &regs->ctrl);
> +	flexcan_write(reg, &regs->ctrl);
>  
>  	flexcan_chip_enable(priv);
>  
>  	/* set freeze, halt and activate FIFO, restrict register access */
> -	reg = readl(&regs->mcr);
> +	reg = flexcan_read(&regs->mcr);
>  	reg |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_HALT |
>  		FLEXCAN_MCR_FEN | FLEXCAN_MCR_SUPV;
> -	writel(reg, &regs->mcr);
> +	flexcan_write(reg, &regs->mcr);
>  
>  	/*
>  	 * Currently we only support newer versions of this core
>  	 * featuring a RX FIFO. Older cores found on some Coldfire
>  	 * derivates are not yet supported.
>  	 */
> -	reg = readl(&regs->mcr);
> +	reg = flexcan_read(&regs->mcr);
>  	if (!(reg & FLEXCAN_MCR_FEN)) {
>  		dev_err(dev->dev.parent,
>  			"Could not enable RX FIFO, unsupported core\n");
> @@ -984,6 +979,7 @@ static int __devinit register_flexcandev(struct net_device *dev)
>  
>  	err = register_candev(dev);
>  
> +	return err;

If you return here, the clock stays enabled....not good

>   out:
>  	/* disable core and turn off clocks */
>  	flexcan_chip_disable(priv);
> @@ -992,7 +988,7 @@ static int __devinit register_flexcandev(struct net_device *dev)
>  	return err;
>  }
>  
> -static void __devexit unregister_flexcandev(struct net_device *dev)
> +void __devexit unregister_flexcandev(struct net_device *dev)
>  {
>  	unregister_candev(dev);
>  }
> diff --git a/drivers/net/can/flexcan_iface.c b/drivers/net/can/flexcan_iface.c
> new file mode 100644
> index 0000000..0c5f6dd
> --- /dev/null
> +++ b/drivers/net/can/flexcan_iface.c
> @@ -0,0 +1,261 @@
> +/*
> + * flexcan_iface.c
> + *
> + * Copyright 2011 Freescale Semiconductor, Inc.
> + *
> + * Based on code originally by Andrey Volkov <[email-masked]>
> + *
> + * LICENCE:
> + * 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 version 2.
> + *
> + * 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/netdevice.h>
> +#include <linux/can/platform/flexcan.h>
> +
> +struct flexcan_interface flexcan_ops;
> +
> +/**
> + * flexcan_of_get_clk_rate - returns the rate, used for bit-timing
> + *				calculations of FlexCAN
> + */
> +static unsigned long flexcan_of_get_clk_rate(struct clk *clock)
> +{
> +	return clock->rate;
> +}
> +
> +static void flexcan_of_clk_put(struct clk *clk)
> +{
> +	kfree(clk);
> +}
> +
> +/**
> + * flexcan_of_clk_get - calculates the rate, used for bit-timing
> + *			calculations of FlexCAN
> + * @dev: the FlexCAN device to be used
> + * @id: id used to differentiate among different clock nodes
> + *
> + * calculate the rate based on the clock-frequency
> + * and clock-divider values from device tree.
> + * It calculate the rate being "platform" as the clock source
> + * Framework for "oscillator" as clock source is also provided.
> + *
> + * Return value
> + *    - On Success
> + *         the rate as part of clk struct, used to calculate the bit-timing
> + *	   for FlexCAN
> + *    - On Failure
> + *	   error value
> + */
> +static struct clk *flexcan_of_clk_get(struct device *dev, const char *id)
> +{
> +	struct clk *clock;
> +	u32 *clock_freq = NULL;
> +	u32 *clock_divider = NULL;
> +	const char *clk_source;
> +	int err;
> +	unsigned long rate;
> +
> +	clk_source = (char *)of_get_property(dev->of_node,
> +			"fsl,flexcan-clock-source", NULL);
> +	if (clk_source == NULL) {
> +		dev_err(dev, "Cannot find fsl,flexcan-clock-source"
> +				"property\n");
> +		err = -EINVAL;
> +		goto failed_clock;
> +	}
> +	if (!memcmp(clk_source, "platform", strlen(clk_source))) {
> +		clock_divider = (u32 *)of_get_property(dev->of_node,
> +				"fsl,flexcan-clock-divider", NULL);
> +		if (*clock_divider) {
> +			clock_freq = (u32 *) of_get_property(dev->of_node,
> +					"clock-frequency", NULL);
> +			if (clock_freq == NULL) {
> +				dev_err(dev, "Cannot find clock-frequency"
> +							"property\n");
> +				err = -EINVAL;
> +				goto failed_clock;
> +			}
> +			rate = DIV_ROUND_CLOSEST(*clock_freq / *clock_divider,
> +						1000) * 1000;
> +		} else {
> +			dev_err(dev, "Cannot find valid fsl,"
> +					"flexcan-clock-divider\n");
> +			err = -EINVAL;
> +			goto failed_clock;
> +		}
> +	} else if (!memcmp(clk_source, "oscillator", strlen(clk_source))) {
> +		clock_divider = (u32 *)of_get_property(dev->of_node,
> +				"fsl,flexcan-clock-divider", NULL);
> +		clock_freq = (u32 *)of_get_property(dev->of_node,
> +						"clock-frequency", NULL);
> +		if (!(*clock_divider && *clock_freq)) {
> +			dev_err(dev, "Cannot find valid"
> +					"fsl,flexcan-clock-divider or"
> +					"clock-frequency\n");
> +			err = -EINVAL;
> +			goto failed_clock;
> +		} else { /*FIXME for keeping oscillator as clock-source*/
> +				dev_err(dev, "oscillator as clock support is"
> +						"not available\n");
> +				err = -EINVAL;
> +				goto failed_clock;
> +		}
> +	} else {
> +		dev_err(dev, "Invalid flexcan-clock-source\n");
> +		err = -EINVAL;
> +		goto failed_clock;
> +	}
> +
> +	clock = kmalloc(sizeof(struct clk), GFP_KERNEL);
> +	if (!clock) {
> +		dev_err(dev, "Cannot allocate memory\n");
> +			err = -ENOMEM;
> +		goto failed_clock;
> +	}
> +
> +	clock->rate = rate;
> +	dev_info(dev, "clock-frequency is  %lu in line %d in function %s\r\n",
> +			clock->rate, __LINE__, __func__);
> +	return clock;
> +
> + failed_clock:
> +	return ERR_PTR(err);
> +}
> +
> +/**
> + * flexcan_of_resource_init - initialize the resources for
> + *				"of" type platform like powerpc
> + * @flexcan_res: input buffer filled with address for accessing h/w registers
> + *		of FlexCAN
> + * @pdev: the FlexCAN device to be used
> + * @flexcan_ops: input buffer containing different utility functions
> + *
> + * fills the flexcan_res with the address detail
> + * for accessing the h/w registers of FlexCAN block.
> + * flexcan_ops is filled with different clock functions and normal read/write
> + *
> + * Return value
> + *    - On Success
> + *	       0
> + *    - On Failure
> + *	   error value
> + */
> +static int flexcan_of_resource_init(struct flexcan_resource *flexcan_res,
> +					struct device *pdev,
> +					struct flexcan_interface *flexcan_ops)
> +{
> +	u64 addr, size;
> +	int err, irq;
> +
> +	addr = of_translate_address(pdev->of_node,
> +			of_get_address(pdev->of_node, 0, &size, NULL));
> +	flexcan_res->addr = addr;
> +	flexcan_res->size = size;
> +	flexcan_res->drv_name = pdev->driver->name;
> +	irq = irq_of_parse_and_map(pdev->of_node, 0);
> +	if (irq == NO_IRQ) {
> +		dev_err(pdev, "cannot map to irq\n");
> +		err = -EINVAL;
> +		goto failed_req;
> +	}
> +
> +	flexcan_res->irq = irq;
> +
> +	flexcan_ops->clk_enable = NULL;
> +	flexcan_ops->clk_disable = NULL;
> +	flexcan_ops->clk_get_rate = flexcan_of_get_clk_rate;
> +	flexcan_ops->clk_get = flexcan_of_clk_get;
> +	flexcan_ops->clk_put = flexcan_of_clk_put;
> +	return 0;
> +
> +failed_req:
> +	return err;
> +}
> +
> +
> +
> +/**
> + * flexcan_probe - performs the resource initialization
> + *		   after detecting the architecture type like "of" or
> + *		   "platform" type
> + * @pdev: pointer to platform device
> + *
> + * initialises the resources based on "platform" or "of"
> + * type architecture.It also registers the FlexCAN with netdev layer.
> + *
> + * Return value
> + *    - On Success
> + *	       0
> + *    - On Failure
> + *	   error value
> + */
> +static int flexcan_probe(struct platform_device *pdev)
> +{
> +	int err;
> +	struct flexcan_resource flexcan_res;
> +	struct device_node *np = pdev->dev.of_node;
> +
> +	if (np) {
> +		err = flexcan_of_resource_init(&flexcan_res,
> +					&pdev->dev, &flexcan_ops);
> +		if (err) {
> +			dev_err(&pdev->dev, "Flexcan Initialization"
> +				 "failed with err (%d)\n", err);
> +			err = -EINVAL;
> +			goto failed_req;
> +		}
> +	}
> +
> +	err = flexcan_dev_init(&pdev->dev, flexcan_res, &flexcan_ops);
> +	if (err) {
> +		dev_err(&pdev->dev, "Flexcan Initialization failed with err"
> +				"(%d)\n", err);
> +		err = -EINVAL;
> +		goto failed_req;
> +	}
> +
> +	return 0;
> + failed_req:
> +	return err;
> +}
> +
> +/**
> + * flexcan_remove - performs the resource de-initialization
> + *		    after detecting the architecture type like "of" or
> + *		    "platform" type
> + * @pdev: pointer to platform device
> + *
> + * de-initializez the resources based on "platform" or "of"
> + * type architecture.It also unregister the FlexCAN with netdev layer.
> + */
> +static int flexcan_remove(struct platform_device *pdev)
> +{
> +	struct net_device *dev = platform_get_drvdata(pdev);
> +	struct flexcan_priv *priv = netdev_priv(dev);
> +	struct device_node *np = pdev->dev.of_node;
> +	struct resource *mem;
> +	u64 addr = 0, size;
> +
> +	unregister_flexcandev(dev);
> +	iounmap(priv->base);
> +
> +	if (np) {
> +		addr = of_translate_address(pdev->dev.of_node,
> +		    of_get_address(pdev->dev.of_node, 0, &size, NULL));
> +		release_mem_region(addr, size);
> +	}	clk_put(priv->clk);
> +
> +	platform_set_drvdata(pdev, NULL);
> +	free_candev(dev);
> +
> +	return 0;
> +}
> +

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |