[PATCH v2 0/3] can: sja1000: support for technologic version

[PATCH v2 0/3] can: sja1000: support for technologic version

[Damien Riegel]

This patchset introduces support for the technologic version of the
SJA1000. Access to IP's registers are proxied through a window,
requiring two bus accesses to read or write a register. These accesses
must be protected by a spinlock to prevent race conditions. Currently,
there is no easy way to allocate and initialize this spinlock.

SJA1000 already provides a way to allocate private data, but
sja1000_platform.c makes no use of it.

Patch 1 adds the capability to allocate and initialize private data on a
per-compatible basis in sja1000_platform.c.

Patch 2 updates device tree documentation to add the technologic
version.

Patch 3 updates the driver to implement the technologic version

Changes in v2:
 - added a patch to allocate and initialize private data
 - changed device tree documentation
 - added a spinlock to protect bus accesses
 - changed sp_{read,write}_reg16 to io{read,write}16

Damien Riegel (3):
  can: sja1000: of: add per-compatible init hook
  can: sja1000: add documentation for Technologic Systems version
  can: sja1000: of: add compatibility with Technologic Systems version

 .../devicetree/bindings/net/can/sja1000.txt        |  3 +-
 drivers/net/can/sja1000/sja1000_platform.c         | 86 +++++++++++++++++++++-
 2 files changed, 86 insertions(+), 3 deletions(-)

-- 
2.5.0

[PATCH v2 1/3] can: sja1000: of: add per-compatible init hook

[Damien Riegel]

This commit adds the capability to allocate and init private data
embedded in the sja1000_priv structure on a per-compatible basis. The
device node is passed as a parameter of the init callback to allow
parsing of custom device tree properties.

Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
---
 drivers/net/can/sja1000/sja1000_platform.c | 39 ++++++++++++++++++++++++++++--
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/sja1000/sja1000_platform.c b/drivers/net/can/sja1000/sja1000_platform.c
index 0552ed4..e0572d0 100644
--- a/drivers/net/can/sja1000/sja1000_platform.c
+++ b/drivers/net/can/sja1000/sja1000_platform.c
@@ -40,6 +40,11 @@ MODULE_DESCRIPTION("Socket-CAN driver for SJA1000 on the platform bus");
 MODULE_ALIAS("platform:" DRV_NAME);
 MODULE_LICENSE("GPL v2");
 
+struct sja1000_of_data {
+	size_t  priv_sz;
+	int     (*init)(struct sja1000_priv *priv, struct device_node *of);
+};
+
 static u8 sp_read_reg8(const struct sja1000_priv *priv, int reg)
 {
 	return ioread8(priv->reg_base + reg);
@@ -154,7 +159,8 @@ static void sp_populate_of(struct sja1000_priv *priv, struct device_node *of)
 		priv->cdr |= CDR_CBP; /* default */
 }
 
-static int sp_probe(struct platform_device *pdev)
+static int __sp_probe(struct platform_device *pdev,
+		      const struct sja1000_of_data *of_data)
 {
 	int err, irq = 0;
 	void __iomem *addr;
@@ -163,6 +169,7 @@ static int sp_probe(struct platform_device *pdev)
 	struct resource *res_mem, *res_irq = NULL;
 	struct sja1000_platform_data *pdata;
 	struct device_node *of = pdev->dev.of_node;
+	size_t priv_sz = of_data ? of_data->priv_sz : 0;
 
 	pdata = dev_get_platdata(&pdev->dev);
 	if (!pdata && !of) {
@@ -191,7 +198,7 @@ static int sp_probe(struct platform_device *pdev)
 	if (!irq && !res_irq)
 		return -ENODEV;
 
-	dev = alloc_sja1000dev(0);
+	dev = alloc_sja1000dev(priv_sz);
 	if (!dev)
 		return -ENOMEM;
 	priv = netdev_priv(dev);
@@ -213,6 +220,12 @@ static int sp_probe(struct platform_device *pdev)
 	else
 		sp_populate(priv, pdata, res_mem->flags);
 
+	if (of_data && of_data->init) {
+		err = of_data->init(priv, of);
+		if (err)
+			goto exit_free;
+	}
+
 	platform_set_drvdata(pdev, dev);
 	SET_NETDEV_DEV(dev, &pdev->dev);
 
@@ -248,6 +261,28 @@ static const struct of_device_id sp_of_table[] = {
 };
 MODULE_DEVICE_TABLE(of, sp_of_table);
 
+static const struct sja1000_of_data *sp_get_of_data(struct device_node *of)
+{
+	const struct of_device_id *id;
+
+	if (!of)
+		return NULL;
+
+	id = of_match_node(sp_of_table, of);
+	if (!id)
+		return NULL;
+
+	return id->data;
+}
+
+static int sp_probe(struct platform_device *pdev)
+{
+	struct device_node *of = pdev->dev.of_node;
+	const struct sja1000_of_data *of_data = sp_get_of_data(of);
+
+	return __sp_probe(pdev, of_data);
+}
+
 static struct platform_driver sp_driver = {
 	.probe = sp_probe,
 	.remove = sp_remove,
-- 
2.5.0

[PATCH v2 2/3] can: sja1000: add documentation for Technologic Systems version

[Damien Riegel]

This commit adds documentation for the Technologic Systems version of
SJA1000. The difference with the NXP version is in the way the registers
are accessed.

Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
---
 Documentation/devicetree/bindings/net/can/sja1000.txt | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/net/can/sja1000.txt b/Documentation/devicetree/bindings/net/can/sja1000.txt
index b4a6d53..ac3160e 100644
--- a/Documentation/devicetree/bindings/net/can/sja1000.txt
+++ b/Documentation/devicetree/bindings/net/can/sja1000.txt
@@ -2,7 +2,7 @@ Memory mapped SJA1000 CAN controller from NXP (formerly Philips)
 
 Required properties:
 
-- compatible : should be "nxp,sja1000".
+- compatible : should be one of "nxp,sja1000", "technologic,sja1000".
 
 - reg : should specify the chip select, address offset and size required
 	to map the registers of the SJA1000. The size is usually 0x80.
@@ -14,6 +14,7 @@ Optional properties:
 
 - reg-io-width : Specify the size (in bytes) of the IO accesses that
 	should be performed on the device.  Valid value is 1, 2 or 4.
+	This property is ignored for technologic version.
 	Default to 1 (8 bits).
 
 - nxp,external-clock-frequency : Frequency of the external oscillator
-- 
2.5.0

[PATCH v2 3/3] can: sja1000: of: add compatibility with Technologic Systems version

[Damien Riegel]

Technologic Systems provides an IP compatible with the SJA1000,
instantiated in an FPGA. Because of some bus widths issue, access to
registers is made through a "window" that works like this:

    base + 0x0: address to read/write
    base + 0x2: 8-bit register value

This commit adds a new compatible device, "technologic,sja1000", with
read and write functions using the window mechanism.

Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
---
 drivers/net/can/sja1000/sja1000_platform.c | 47 ++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/drivers/net/can/sja1000/sja1000_platform.c b/drivers/net/can/sja1000/sja1000_platform.c
index e0572d0..bfb124d 100644
--- a/drivers/net/can/sja1000/sja1000_platform.c
+++ b/drivers/net/can/sja1000/sja1000_platform.c
@@ -45,6 +45,10 @@ struct sja1000_of_data {
 	int     (*init)(struct sja1000_priv *priv, struct device_node *of);
 };
 
+struct technologic_priv {
+	spinlock_t      io_lock;
+};
+
 static u8 sp_read_reg8(const struct sja1000_priv *priv, int reg)
 {
 	return ioread8(priv->reg_base + reg);
@@ -75,6 +79,43 @@ static void sp_write_reg32(const struct sja1000_priv *priv, int reg, u8 val)
 	iowrite8(val, priv->reg_base + reg * 4);
 }
 
+static u8 technologic_read_reg16(const struct sja1000_priv *priv, int reg)
+{
+	struct technologic_priv *tp = priv->priv;
+	unsigned long flags;
+	u8 val;
+
+	spin_lock_irqsave(&tp->io_lock, flags);
+	iowrite16(reg, priv->reg_base + 0);
+	val = ioread16(priv->reg_base + 2);
+	spin_unlock_irqrestore(&tp->io_lock, flags);
+
+	return val;
+}
+
+static void technologic_write_reg16(const struct sja1000_priv *priv,
+				    int reg, u8 val)
+{
+	struct technologic_priv *tp = priv->priv;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tp->io_lock, flags);
+	iowrite16(reg, priv->reg_base + 0);
+	iowrite16(val, priv->reg_base + 2);
+	spin_unlock_irqrestore(&tp->io_lock, flags);
+}
+
+static int technologic_init(struct sja1000_priv *priv, struct device_node *of)
+{
+	struct technologic_priv *tp = priv->priv;
+
+	priv->read_reg = technologic_read_reg16;
+	priv->write_reg = technologic_write_reg16;
+	spin_lock_init(&tp->io_lock);
+
+	return 0;
+}
+
 static void sp_populate(struct sja1000_priv *priv,
 			struct sja1000_platform_data *pdata,
 			unsigned long resource_mem_flags)
@@ -255,8 +296,14 @@ static int sp_remove(struct platform_device *pdev)
 	return 0;
 }
 
+struct sja1000_of_data technologic_data = {
+	.priv_sz = sizeof(struct technologic_priv),
+	.init = technologic_init,
+};
+
 static const struct of_device_id sp_of_table[] = {
 	{.compatible = "nxp,sja1000"},
+	{.compatible = "technologic,sja1000", .data = &technologic_data},
 	{},
 };
 MODULE_DEVICE_TABLE(of, sp_of_table);
-- 
2.5.0

Re: [PATCH v2 0/3] can: sja1000: support for technologic version

[Damien Riegel]

Hi Marc,

On Thu, Dec 24, 2015 at 12:42:50PM -0500, Damien Riegel wrote:
> This patchset introduces support for the technologic version of the
> SJA1000. Access to IP's registers are proxied through a window,
> requiring two bus accesses to read or write a register. These accesses
> must be protected by a spinlock to prevent race conditions. Currently,
> there is no easy way to allocate and initialize this spinlock.
> 
> SJA1000 already provides a way to allocate private data, but
> sja1000_platform.c makes no use of it.
> 
> Patch 1 adds the capability to allocate and initialize private data on a
> per-compatible basis in sja1000_platform.c.
> 
> Patch 2 updates device tree documentation to add the technologic
> version.
> 
> Patch 3 updates the driver to implement the technologic version
> 

Did you have a chance to take a look at this patchset? I would
appreciate your feedback, especially on the first patch.


Thanks,
Damien

Re: [PATCH v2 1/3] can: sja1000: of: add per-compatible init hook

[Marc Kleine-Budde]

[-- Attachment #1: Type: text/plain, Size: 3642 bytes --]

On 12/24/2015 06:42 PM, Damien Riegel wrote:
> This commit adds the capability to allocate and init private data
> embedded in the sja1000_priv structure on a per-compatible basis. The
> device node is passed as a parameter of the init callback to allow
> parsing of custom device tree properties.
> 
> Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
> ---
>  drivers/net/can/sja1000/sja1000_platform.c | 39 ++++++++++++++++++++++++++++--
>  1 file changed, 37 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/can/sja1000/sja1000_platform.c b/drivers/net/can/sja1000/sja1000_platform.c
> index 0552ed4..e0572d0 100644
> --- a/drivers/net/can/sja1000/sja1000_platform.c
> +++ b/drivers/net/can/sja1000/sja1000_platform.c
> @@ -40,6 +40,11 @@ MODULE_DESCRIPTION("Socket-CAN driver for SJA1000 on the platform bus");
>  MODULE_ALIAS("platform:" DRV_NAME);
>  MODULE_LICENSE("GPL v2");
>  
> +struct sja1000_of_data {
> +	size_t  priv_sz;
> +	int     (*init)(struct sja1000_priv *priv, struct device_node *of);
> +};
> +
>  static u8 sp_read_reg8(const struct sja1000_priv *priv, int reg)
>  {
>  	return ioread8(priv->reg_base + reg);
> @@ -154,7 +159,8 @@ static void sp_populate_of(struct sja1000_priv *priv, struct device_node *of)
>  		priv->cdr |= CDR_CBP; /* default */
>  }
>  
> -static int sp_probe(struct platform_device *pdev)
> +static int __sp_probe(struct platform_device *pdev,
> +		      const struct sja1000_of_data *of_data)
>  {
>  	int err, irq = 0;
>  	void __iomem *addr;
> @@ -163,6 +169,7 @@ static int sp_probe(struct platform_device *pdev)
>  	struct resource *res_mem, *res_irq = NULL;
>  	struct sja1000_platform_data *pdata;
>  	struct device_node *of = pdev->dev.of_node;
> +	size_t priv_sz = of_data ? of_data->priv_sz : 0;
>  
>  	pdata = dev_get_platdata(&pdev->dev);
>  	if (!pdata && !of) {
> @@ -191,7 +198,7 @@ static int sp_probe(struct platform_device *pdev)
>  	if (!irq && !res_irq)
>  		return -ENODEV;
>  
> -	dev = alloc_sja1000dev(0);
> +	dev = alloc_sja1000dev(priv_sz);
>  	if (!dev)
>  		return -ENOMEM;
>  	priv = netdev_priv(dev);
> @@ -213,6 +220,12 @@ static int sp_probe(struct platform_device *pdev)
>  	else
>  		sp_populate(priv, pdata, res_mem->flags);
>  
> +	if (of_data && of_data->init) {
> +		err = of_data->init(priv, of);
> +		if (err)
> +			goto exit_free;
> +	}
> +
>  	platform_set_drvdata(pdev, dev);
>  	SET_NETDEV_DEV(dev, &pdev->dev);
>  
> @@ -248,6 +261,28 @@ static const struct of_device_id sp_of_table[] = {
>  };
>  MODULE_DEVICE_TABLE(of, sp_of_table);
>  
> +static const struct sja1000_of_data *sp_get_of_data(struct device_node *of)
> +{
> +	const struct of_device_id *id;
> +
> +	if (!of)
> +		return NULL;
> +
> +	id = of_match_node(sp_of_table, of);
> +	if (!id)
> +		return NULL;
> +
> +	return id->data;
> +}
> +
> +static int sp_probe(struct platform_device *pdev)
> +{
> +	struct device_node *of = pdev->dev.of_node;
> +	const struct sja1000_of_data *of_data = sp_get_of_data(of);
> +
> +	return __sp_probe(pdev, of_data);
> +}

Please merge these two into the original sp_probe function, as there
already is a test for pdev->dev.of_node.

> +
>  static struct platform_driver sp_driver = {
>  	.probe = sp_probe,
>  	.remove = sp_remove,
> 

Marc

-- 
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   |


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Re: [PATCH v2 3/3] can: sja1000: of: add compatibility with Technologic Systems version

[Marc Kleine-Budde]

[-- Attachment #1: Type: text/plain, Size: 678 bytes --]

On 12/24/2015 06:42 PM, Damien Riegel wrote:
> Technologic Systems provides an IP compatible with the SJA1000,
> instantiated in an FPGA. Because of some bus widths issue, access to
> registers is made through a "window" that works like this:
> 
>     base + 0x0: address to read/write
>     base + 0x2: 8-bit register value

Why do you use io{read,write}16 if it's a 8 bit register?

Marc

-- 
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   |


[-- Attachment #2: OpenPGP digital signature --]
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Re: [PATCH v2 0/3] can: sja1000: support for technologic version

[Marc Kleine-Budde]

[-- Attachment #1: Type: text/plain, Size: 1355 bytes --]

On 01/11/2016 05:58 PM, Damien Riegel wrote:
> Hi Marc,
> 
> On Thu, Dec 24, 2015 at 12:42:50PM -0500, Damien Riegel wrote:
>> This patchset introduces support for the technologic version of the
>> SJA1000. Access to IP's registers are proxied through a window,
>> requiring two bus accesses to read or write a register. These accesses
>> must be protected by a spinlock to prevent race conditions. Currently,
>> there is no easy way to allocate and initialize this spinlock.
>>
>> SJA1000 already provides a way to allocate private data, but
>> sja1000_platform.c makes no use of it.
>>
>> Patch 1 adds the capability to allocate and initialize private data on a
>> per-compatible basis in sja1000_platform.c.
>>
>> Patch 2 updates device tree documentation to add the technologic
>> version.
>>
>> Patch 3 updates the driver to implement the technologic version
>>
> 
> Did you have a chance to take a look at this patchset? I would
> appreciate your feedback, especially on the first patch.

Done. 2/3 is ok. For the others see my comments.

Marc

-- 
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   |


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 455 bytes --]

Re: [PATCH v2 3/3] can: sja1000: of: add compatibility with Technologic Systems version

[Damien Riegel]

On Tue, Jan 12, 2016 at 08:55:38AM +0100, Marc Kleine-Budde wrote:
> On 12/24/2015 06:42 PM, Damien Riegel wrote:
> > Technologic Systems provides an IP compatible with the SJA1000,
> > instantiated in an FPGA. Because of some bus widths issue, access to
> > registers is made through a "window" that works like this:
> > 
> >     base + 0x0: address to read/write
> >     base + 0x2: 8-bit register value
> 
> Why do you use io{read,write}16 if it's a 8 bit register?

8-bit is at the IP level, but the bus between the SoC and the FPGA only
supports 16-bit wide access. The point of the window is to convert
between 16-bit and 8-bit access.

Damien

Re: [PATCH v2 1/3] can: sja1000: of: add per-compatible init hook

[Damien Riegel]

On Tue, Jan 12, 2016 at 08:52:06AM +0100, Marc Kleine-Budde wrote:
> On 12/24/2015 06:42 PM, Damien Riegel wrote:
> > This commit adds the capability to allocate and init private data
> > embedded in the sja1000_priv structure on a per-compatible basis. The
> > device node is passed as a parameter of the init callback to allow
> > parsing of custom device tree properties.
> > 
> > Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
> > ---
> >  drivers/net/can/sja1000/sja1000_platform.c | 39 ++++++++++++++++++++++++++++--
> >  1 file changed, 37 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/net/can/sja1000/sja1000_platform.c b/drivers/net/can/sja1000/sja1000_platform.c
> > index 0552ed4..e0572d0 100644
> > --- a/drivers/net/can/sja1000/sja1000_platform.c
> > +++ b/drivers/net/can/sja1000/sja1000_platform.c
> > @@ -40,6 +40,11 @@ MODULE_DESCRIPTION("Socket-CAN driver for SJA1000 on the platform bus");
> >  MODULE_ALIAS("platform:" DRV_NAME);
> >  MODULE_LICENSE("GPL v2");
> >  
> > +struct sja1000_of_data {
> > +	size_t  priv_sz;
> > +	int     (*init)(struct sja1000_priv *priv, struct device_node *of);
> > +};
> > +
> >  static u8 sp_read_reg8(const struct sja1000_priv *priv, int reg)
> >  {
> >  	return ioread8(priv->reg_base + reg);
> > @@ -154,7 +159,8 @@ static void sp_populate_of(struct sja1000_priv *priv, struct device_node *of)
> >  		priv->cdr |= CDR_CBP; /* default */
> >  }
> >  
> > -static int sp_probe(struct platform_device *pdev)
> > +static int __sp_probe(struct platform_device *pdev,
> > +		      const struct sja1000_of_data *of_data)
> >  {
> >  	int err, irq = 0;
> >  	void __iomem *addr;
> > @@ -163,6 +169,7 @@ static int sp_probe(struct platform_device *pdev)
> >  	struct resource *res_mem, *res_irq = NULL;
> >  	struct sja1000_platform_data *pdata;
> >  	struct device_node *of = pdev->dev.of_node;
> > +	size_t priv_sz = of_data ? of_data->priv_sz : 0;
> >  
> >  	pdata = dev_get_platdata(&pdev->dev);
> >  	if (!pdata && !of) {
> > @@ -191,7 +198,7 @@ static int sp_probe(struct platform_device *pdev)
> >  	if (!irq && !res_irq)
> >  		return -ENODEV;
> >  
> > -	dev = alloc_sja1000dev(0);
> > +	dev = alloc_sja1000dev(priv_sz);
> >  	if (!dev)
> >  		return -ENOMEM;
> >  	priv = netdev_priv(dev);
> > @@ -213,6 +220,12 @@ static int sp_probe(struct platform_device *pdev)
> >  	else
> >  		sp_populate(priv, pdata, res_mem->flags);
> >  
> > +	if (of_data && of_data->init) {
> > +		err = of_data->init(priv, of);
> > +		if (err)
> > +			goto exit_free;
> > +	}
> > +
> >  	platform_set_drvdata(pdev, dev);
> >  	SET_NETDEV_DEV(dev, &pdev->dev);
> >  
> > @@ -248,6 +261,28 @@ static const struct of_device_id sp_of_table[] = {
> >  };
> >  MODULE_DEVICE_TABLE(of, sp_of_table);
> >  
> > +static const struct sja1000_of_data *sp_get_of_data(struct device_node *of)
> > +{
> > +	const struct of_device_id *id;
> > +
> > +	if (!of)
> > +		return NULL;
> > +
> > +	id = of_match_node(sp_of_table, of);
> > +	if (!id)
> > +		return NULL;
> > +
> > +	return id->data;
> > +}
> > +
> > +static int sp_probe(struct platform_device *pdev)
> > +{
> > +	struct device_node *of = pdev->dev.of_node;
> > +	const struct sja1000_of_data *of_data = sp_get_of_data(of);
> > +
> > +	return __sp_probe(pdev, of_data);
> > +}
> 
> Please merge these two into the original sp_probe function, as there
> already is a test for pdev->dev.of_node.

Ok. sp_get_of_data makes use of sp_of_table, so either I move sp_probe
below sp_of_table, or I use a forward declaration. Which one do you
prefer?

Damien

Re: [PATCH v2 1/3] can: sja1000: of: add per-compatible init hook

[Marc Kleine-Budde]

On January 12, 2016 4:53:30 PM GMT+01:00, Damien Riegel <damien.riegel@savoirfairelinux.com> wrote:
>On Tue, Jan 12, 2016 at 08:52:06AM +0100, Marc Kleine-Budde wrote:
>> On 12/24/2015 06:42 PM, Damien Riegel wrote:
>> > This commit adds the capability to allocate and init private data
>> > embedded in the sja1000_priv structure on a per-compatible basis.
>The
>> > device node is passed as a parameter of the init callback to allow
>> > parsing of custom device tree properties.
>> > 
>> > Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
>> > ---
>> >  drivers/net/can/sja1000/sja1000_platform.c | 39
>++++++++++++++++++++++++++++--
>> >  1 file changed, 37 insertions(+), 2 deletions(-)
>> > 
>> > diff --git a/drivers/net/can/sja1000/sja1000_platform.c
>b/drivers/net/can/sja1000/sja1000_platform.c
>> > index 0552ed4..e0572d0 100644
>> > --- a/drivers/net/can/sja1000/sja1000_platform.c
>> > +++ b/drivers/net/can/sja1000/sja1000_platform.c
>> > @@ -40,6 +40,11 @@ MODULE_DESCRIPTION("Socket-CAN driver for
>SJA1000 on the platform bus");
>> >  MODULE_ALIAS("platform:" DRV_NAME);
>> >  MODULE_LICENSE("GPL v2");
>> >  
>> > +struct sja1000_of_data {
>> > +	size_t  priv_sz;
>> > +	int     (*init)(struct sja1000_priv *priv, struct device_node
>*of);
>> > +};
>> > +
>> >  static u8 sp_read_reg8(const struct sja1000_priv *priv, int reg)
>> >  {
>> >  	return ioread8(priv->reg_base + reg);
>> > @@ -154,7 +159,8 @@ static void sp_populate_of(struct sja1000_priv
>*priv, struct device_node *of)
>> >  		priv->cdr |= CDR_CBP; /* default */
>> >  }
>> >  
>> > -static int sp_probe(struct platform_device *pdev)
>> > +static int __sp_probe(struct platform_device *pdev,
>> > +		      const struct sja1000_of_data *of_data)
>> >  {
>> >  	int err, irq = 0;
>> >  	void __iomem *addr;
>> > @@ -163,6 +169,7 @@ static int sp_probe(struct platform_device
>*pdev)
>> >  	struct resource *res_mem, *res_irq = NULL;
>> >  	struct sja1000_platform_data *pdata;
>> >  	struct device_node *of = pdev->dev.of_node;
>> > +	size_t priv_sz = of_data ? of_data->priv_sz : 0;
>> >  
>> >  	pdata = dev_get_platdata(&pdev->dev);
>> >  	if (!pdata && !of) {
>> > @@ -191,7 +198,7 @@ static int sp_probe(struct platform_device
>*pdev)
>> >  	if (!irq && !res_irq)
>> >  		return -ENODEV;
>> >  
>> > -	dev = alloc_sja1000dev(0);
>> > +	dev = alloc_sja1000dev(priv_sz);
>> >  	if (!dev)
>> >  		return -ENOMEM;
>> >  	priv = netdev_priv(dev);
>> > @@ -213,6 +220,12 @@ static int sp_probe(struct platform_device
>*pdev)
>> >  	else
>> >  		sp_populate(priv, pdata, res_mem->flags);
>> >  
>> > +	if (of_data && of_data->init) {
>> > +		err = of_data->init(priv, of);
>> > +		if (err)
>> > +			goto exit_free;
>> > +	}
>> > +
>> >  	platform_set_drvdata(pdev, dev);
>> >  	SET_NETDEV_DEV(dev, &pdev->dev);
>> >  
>> > @@ -248,6 +261,28 @@ static const struct of_device_id sp_of_table[]
>= {
>> >  };
>> >  MODULE_DEVICE_TABLE(of, sp_of_table);
>> >  
>> > +static const struct sja1000_of_data *sp_get_of_data(struct
>device_node *of)
>> > +{
>> > +	const struct of_device_id *id;
>> > +
>> > +	if (!of)
>> > +		return NULL;
>> > +
>> > +	id = of_match_node(sp_of_table, of);
>> > +	if (!id)
>> > +		return NULL;
>> > +
>> > +	return id->data;
>> > +}
>> > +
>> > +static int sp_probe(struct platform_device *pdev)
>> > +{
>> > +	struct device_node *of = pdev->dev.of_node;
>> > +	const struct sja1000_of_data *of_data = sp_get_of_data(of);
>> > +
>> > +	return __sp_probe(pdev, of_data);
>> > +}
>> 
>> Please merge these two into the original sp_probe function, as there
>> already is a test for pdev->dev.of_node.
>
>Ok. sp_get_of_data makes use of sp_of_table, so either I move sp_probe
>below sp_of_table, or I use a forward declaration. Which one do you
>prefer?

Please move sp_of_table.

Marc