[PATCH v4 0/3] can: sja1000: support for technologic version

[PATCH v4 0/3] can: sja1000: support for technologic version

[Marc Kleine-Budde]

This is Damien Riegel's series with minor changes.

regards,
Marc

---

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 v4:
 - add sp_ prefix to technologic functions
 - add empty "static struct sja1000_of_data nxp_data"
 - make "struct sja1000_of_data technologic_data" static
 - get rid of "?" operator in sp_probe()

Changes in v3:
 - moved sp_of_table above sp_probe as it is used in this function
 - removed functions added in v2 and do everyting in sp_probe

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

[PATCH v4 1/3] can: sja1000: of: add per-compatible init hook

[Marc Kleine-Budde]

From: Damien Riegel <damien.riegel@savoirfairelinux.com>

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>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/sja1000/sja1000_platform.c | 42 +++++++++++++++++++++++-------
 1 file changed, 33 insertions(+), 9 deletions(-)

diff --git a/drivers/net/can/sja1000/sja1000_platform.c b/drivers/net/can/sja1000/sja1000_platform.c
index 0552ed46a206..46378c9dbb29 100644
--- a/drivers/net/can/sja1000/sja1000_platform.c
+++ b/drivers/net/can/sja1000/sja1000_platform.c
@@ -27,6 +27,7 @@
 #include <linux/can/platform/sja1000.h>
 #include <linux/io.h>
 #include <linux/of.h>
+#include <linux/of_device.h>
 #include <linux/of_irq.h>
 
 #include "sja1000.h"
@@ -40,6 +41,11 @@ 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);
@@ -154,6 +160,14 @@ static void sp_populate_of(struct sja1000_priv *priv, struct device_node *of)
 		priv->cdr |= CDR_CBP; /* default */
 }
 
+static struct sja1000_of_data nxp_data;
+
+static const struct of_device_id sp_of_table[] = {
+	{ .compatible = "nxp,sja1000", .data = &nxp_data },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, sp_of_table);
+
 static int sp_probe(struct platform_device *pdev)
 {
 	int err, irq = 0;
@@ -163,6 +177,9 @@ 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;
+	const struct of_device_id *of_id;
+	const struct sja1000_of_data *of_data = NULL;
+	size_t priv_sz = 0;
 
 	pdata = dev_get_platdata(&pdev->dev);
 	if (!pdata && !of) {
@@ -191,7 +208,13 @@ static int sp_probe(struct platform_device *pdev)
 	if (!irq && !res_irq)
 		return -ENODEV;
 
-	dev = alloc_sja1000dev(0);
+	of_id = of_match_device(sp_of_table, &pdev->dev);
+	if (of_id) {
+		of_data = of_id->data;
+		priv_sz = of_data->priv_sz;
+	}
+
+	dev = alloc_sja1000dev(priv_sz);
 	if (!dev)
 		return -ENOMEM;
 	priv = netdev_priv(dev);
@@ -208,10 +231,17 @@ static int sp_probe(struct platform_device *pdev)
 	dev->irq = irq;
 	priv->reg_base = addr;
 
-	if (of)
+	if (of) {
 		sp_populate_of(priv, of);
-	else
+
+		if (of_data->init) {
+			err = of_data->init(priv, of);
+			if (err)
+				goto exit_free;
+		}
+	} else {
 		sp_populate(priv, pdata, res_mem->flags);
+	}
 
 	platform_set_drvdata(pdev, dev);
 	SET_NETDEV_DEV(dev, &pdev->dev);
@@ -242,12 +272,6 @@ static int sp_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static const struct of_device_id sp_of_table[] = {
-	{.compatible = "nxp,sja1000"},
-	{},
-};
-MODULE_DEVICE_TABLE(of, sp_of_table);
-
 static struct platform_driver sp_driver = {
 	.probe = sp_probe,
 	.remove = sp_remove,
-- 
2.6.4

[PATCH v4 2/3] can: sja1000: add documentation for Technologic Systems version

[Marc Kleine-Budde]

From: Damien Riegel <damien.riegel@savoirfairelinux.com>

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>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 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 b4a6d53fb01a..ac3160eca96a 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
-- 
2.6.4

[PATCH v4 3/3] can: sja1000: of: add compatibility with Technologic Systems version

[Marc Kleine-Budde]

From: Damien Riegel <damien.riegel@savoirfairelinux.com>

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>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 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 46378c9dbb29..aad10e8f1de5 100644
--- a/drivers/net/can/sja1000/sja1000_platform.c
+++ b/drivers/net/can/sja1000/sja1000_platform.c
@@ -46,6 +46,10 @@ 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);
@@ -76,6 +80,43 @@ static void sp_write_reg32(const struct sja1000_priv *priv, int reg, u8 val)
 	iowrite8(val, priv->reg_base + reg * 4);
 }
 
+static u8 sp_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 sp_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 sp_technologic_init(struct sja1000_priv *priv, struct device_node *of)
+{
+	struct technologic_priv *tp = priv->priv;
+
+	priv->read_reg = sp_technologic_read_reg16;
+	priv->write_reg = sp_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)
@@ -162,8 +203,14 @@ static void sp_populate_of(struct sja1000_priv *priv, struct device_node *of)
 
 static struct sja1000_of_data nxp_data;
 
+static struct sja1000_of_data technologic_data = {
+	.priv_sz = sizeof(struct technologic_priv),
+	.init = sp_technologic_init,
+};
+
 static const struct of_device_id sp_of_table[] = {
 	{ .compatible = "nxp,sja1000", .data = &nxp_data },
+	{ .compatible = "technologic,sja1000", .data = &technologic_data },
 	{ /* sentinel */ },
 };
 MODULE_DEVICE_TABLE(of, sp_of_table);
-- 
2.6.4

Re: [PATCH v4 1/3] can: sja1000: of: add per-compatible init hook

[Damien Riegel]

Hi Marc,

On Wed, Jan 13, 2016 at 12:46:04PM +0100, Marc Kleine-Budde wrote:
> From: Damien Riegel <damien.riegel@savoirfairelinux.com>
> 
> 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>
> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

I tested your serie and am okay with your changes. Just a minor comment
below, feel free to ignore it if you disagree.

> ---
>  drivers/net/can/sja1000/sja1000_platform.c | 42 +++++++++++++++++++++++-------
>  1 file changed, 33 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/can/sja1000/sja1000_platform.c b/drivers/net/can/sja1000/sja1000_platform.c
> index 0552ed46a206..46378c9dbb29 100644
> --- a/drivers/net/can/sja1000/sja1000_platform.c
> +++ b/drivers/net/can/sja1000/sja1000_platform.c
> @@ -27,6 +27,7 @@
>  #include <linux/can/platform/sja1000.h>
>  #include <linux/io.h>
>  #include <linux/of.h>
> +#include <linux/of_device.h>
>  #include <linux/of_irq.h>
>  
>  #include "sja1000.h"
> @@ -40,6 +41,11 @@ 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);
> @@ -154,6 +160,14 @@ static void sp_populate_of(struct sja1000_priv *priv, struct device_node *of)
>  		priv->cdr |= CDR_CBP; /* default */
>  }
>  
> +static struct sja1000_of_data nxp_data;
> +
> +static const struct of_device_id sp_of_table[] = {
> +	{ .compatible = "nxp,sja1000", .data = &nxp_data },
> +	{ /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, sp_of_table);
> +
>  static int sp_probe(struct platform_device *pdev)
>  {
>  	int err, irq = 0;
> @@ -163,6 +177,9 @@ 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;
> +	const struct of_device_id *of_id;
> +	const struct sja1000_of_data *of_data = NULL;
> +	size_t priv_sz = 0;
>  
>  	pdata = dev_get_platdata(&pdev->dev);
>  	if (!pdata && !of) {
> @@ -191,7 +208,13 @@ static int sp_probe(struct platform_device *pdev)
>  	if (!irq && !res_irq)
>  		return -ENODEV;
>  
> -	dev = alloc_sja1000dev(0);
> +	of_id = of_match_device(sp_of_table, &pdev->dev);
> +	if (of_id) {

My personal preference here would be to test of_id && of_id->data. That
way, we could avoid the declaration of nxp_data. It would also be a bit
less error prone if someone adds a new compatible in the of device
table.

Thanks,
Damien

> +		of_data = of_id->data;
> +		priv_sz = of_data->priv_sz;
> +	}
> +
> +	dev = alloc_sja1000dev(priv_sz);
>  	if (!dev)
>  		return -ENOMEM;
>  	priv = netdev_priv(dev);
> @@ -208,10 +231,17 @@ static int sp_probe(struct platform_device *pdev)
>  	dev->irq = irq;
>  	priv->reg_base = addr;
>  
> -	if (of)
> +	if (of) {
>  		sp_populate_of(priv, of);
> -	else
> +
> +		if (of_data->init) {
> +			err = of_data->init(priv, of);
> +			if (err)
> +				goto exit_free;
> +		}
> +	} else {
>  		sp_populate(priv, pdata, res_mem->flags);
> +	}
>  
>  	platform_set_drvdata(pdev, dev);
>  	SET_NETDEV_DEV(dev, &pdev->dev);
> @@ -242,12 +272,6 @@ static int sp_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> -static const struct of_device_id sp_of_table[] = {
> -	{.compatible = "nxp,sja1000"},
> -	{},
> -};
> -MODULE_DEVICE_TABLE(of, sp_of_table);
> -
>  static struct platform_driver sp_driver = {
>  	.probe = sp_probe,
>  	.remove = sp_remove,
> -- 
> 2.6.4
> 

Re: [PATCH v4 1/3] can: sja1000: of: add per-compatible init hook

[Damien Riegel]

Hi Marc,

On Wed, Jan 13, 2016 at 12:46:04PM +0100, Marc Kleine-Budde wrote:
> From: Damien Riegel <damien.riegel@savoirfairelinux.com>
> 
> 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>
> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

I see that you haven't taken this serie in your tree. What is its
status? Are there still some issues that need to be addressed?

Thanks,
Damien

Re: [PATCH v4 1/3] can: sja1000: of: add per-compatible init hook

[Marc Kleine-Budde]

[-- Attachment #1: Type: text/plain, Size: 1336 bytes --]

On 01/13/2016 04:57 PM, Damien Riegel wrote:
>>  static int sp_probe(struct platform_device *pdev)
>>  {
>>  	int err, irq = 0;
>> @@ -163,6 +177,9 @@ 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;
>> +	const struct of_device_id *of_id;
>> +	const struct sja1000_of_data *of_data = NULL;
>> +	size_t priv_sz = 0;
>>  
>>  	pdata = dev_get_platdata(&pdev->dev);
>>  	if (!pdata && !of) {
>> @@ -191,7 +208,13 @@ static int sp_probe(struct platform_device *pdev)
>>  	if (!irq && !res_irq)
>>  		return -ENODEV;
>>  
>> -	dev = alloc_sja1000dev(0);
>> +	of_id = of_match_device(sp_of_table, &pdev->dev);
>> +	if (of_id) {
> 
> My personal preference here would be to test of_id && of_id->data. That
> way, we could avoid the declaration of nxp_data. It would also be a bit
> less error prone if someone adds a new compatible in the of device
> table.

Ok - please test v5.

regards,
Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
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Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
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