[PATCH v4 0/4] Add link-frequencies to struct v4l2_of_endpoint

[PATCH v4 0/4] Add link-frequencies to struct v4l2_of_endpoint

[Sakari Ailus]

Hi folks,

Here's the fourth version of the link-frequencies patchset, which also
changes how the v4l2_of_endpoint is used.

Since v3:

patch 2:

- Use "zero" when referring to zeroing memory instead of clean.

patch 3:

- Fix interface documentation language.

v3 is available here:

<URL:http://www.spinics.net/lists/linux-media/msg88466.html>

-- 
Kind regards,
Sakari

[PATCH v4 1/4] v4l: of: Remove the head field in struct v4l2_of_endpoint

[Sakari Ailus]

The field is unused. Remove it.

Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
---
 include/media/v4l2-of.h |    2 --
 1 file changed, 2 deletions(-)

diff --git a/include/media/v4l2-of.h b/include/media/v4l2-of.h
index f831c9c..f66b92c 100644
--- a/include/media/v4l2-of.h
+++ b/include/media/v4l2-of.h
@@ -57,7 +57,6 @@ struct v4l2_of_bus_parallel {
  * @base: struct of_endpoint containing port, id, and local of_node
  * @bus_type: bus type
  * @bus: bus configuration data structure
- * @head: list head for this structure
  */
 struct v4l2_of_endpoint {
 	struct of_endpoint base;
@@ -66,7 +65,6 @@ struct v4l2_of_endpoint {
 		struct v4l2_of_bus_parallel parallel;
 		struct v4l2_of_bus_mipi_csi2 mipi_csi2;
 	} bus;
-	struct list_head head;
 };
 
 /**
-- 
1.7.10.4

[PATCH v4 2/4] v4l: of: Instead of zeroing bus_type and bus field separately, unify this

[Sakari Ailus]

Zero the entire struct starting from bus_type. As more fields are added, no
changes will be needed in the function to reset their value explicitly.

Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 drivers/media/v4l2-core/v4l2-of.c |    5 +++--
 include/media/v4l2-of.h           |    1 +
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-of.c b/drivers/media/v4l2-core/v4l2-of.c
index 83143d3..3ac6348 100644
--- a/drivers/media/v4l2-core/v4l2-of.c
+++ b/drivers/media/v4l2-core/v4l2-of.c
@@ -149,8 +149,9 @@ int v4l2_of_parse_endpoint(const struct device_node *node,
 	int rval;
 
 	of_graph_parse_endpoint(node, &endpoint->base);
-	endpoint->bus_type = 0;
-	memset(&endpoint->bus, 0, sizeof(endpoint->bus));
+	/* Zero fields from bus_type to until the end */
+	memset(&endpoint->bus_type, 0, sizeof(*endpoint) -
+	       offsetof(typeof(*endpoint), bus_type));
 
 	rval = v4l2_of_parse_csi_bus(node, endpoint);
 	if (rval)
diff --git a/include/media/v4l2-of.h b/include/media/v4l2-of.h
index f66b92c..6c85c07 100644
--- a/include/media/v4l2-of.h
+++ b/include/media/v4l2-of.h
@@ -60,6 +60,7 @@ struct v4l2_of_bus_parallel {
  */
 struct v4l2_of_endpoint {
 	struct of_endpoint base;
+	/* Fields below this line will be zeroed by v4l2_of_parse_endpoint() */
 	enum v4l2_mbus_type bus_type;
 	union {
 		struct v4l2_of_bus_parallel parallel;
-- 
1.7.10.4

[PATCH v4 3/4] v4l: of: Parse variable length properties --- link-frequencies

[Sakari Ailus]

The link-frequencies property is a variable length array of link frequencies
in an endpoint. The array is needed by an increasing number of drivers, so
it makes sense to add it to struct v4l2_of_endpoint.

However, the length of the array is variable and the size of struct
v4l2_of_endpoint is fixed since it is allocated by the caller. The options
here are

1. to define a fixed maximum limit of link frequencies that has to be the
global maximum of all boards. This is seen as problematic since the maximum
could be largish, and everyone hitting the problem would need to submit a
patch to fix it, or

2. parse the property in every driver. This doesn't sound appealing as two
of the three implementations submitted to linux-media were wrong, and one of
them was even merged before this was noticed, or

3. change the interface so that allocating and releasing memory according to
the size of the array is possible. This is what the patch does.

v4l2_of_alloc_parse_endpoint() is just like v4l2_of_parse_endpoint(), but it
will allocate the memory resources needed to store struct v4l2_of_endpoint
and the additional arrays pointed to by this struct. A corresponding release
function v4l2_of_free_endpoint() is provided to release the memory allocated
by v4l2_of_alloc_parse_endpoint().

In addition to this, the link-frequencies property is parsed as well, and
the result is stored to struct v4l2_of_endpoint field link_frequencies.

Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 drivers/media/v4l2-core/v4l2-of.c |   87 +++++++++++++++++++++++++++++++++++++
 include/media/v4l2-of.h           |   17 ++++++++
 2 files changed, 104 insertions(+)

diff --git a/drivers/media/v4l2-core/v4l2-of.c b/drivers/media/v4l2-core/v4l2-of.c
index 3ac6348..c52fb96 100644
--- a/drivers/media/v4l2-core/v4l2-of.c
+++ b/drivers/media/v4l2-core/v4l2-of.c
@@ -14,6 +14,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/types.h>
 
@@ -141,6 +142,10 @@ static void v4l2_of_parse_parallel_bus(const struct device_node *node,
  * V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag.
  * The caller should hold a reference to @node.
  *
+ * NOTE: This function does not parse properties the size of which is
+ * variable without a low fixed limit. Please use
+ * v4l2_of_alloc_parse_endpoint() in new drivers instead.
+ *
  * Return: 0.
  */
 int v4l2_of_parse_endpoint(const struct device_node *node,
@@ -167,6 +172,88 @@ int v4l2_of_parse_endpoint(const struct device_node *node,
 }
 EXPORT_SYMBOL(v4l2_of_parse_endpoint);
 
+/*
+ * v4l2_of_free_endpoint() - free the endpoint acquired by
+ * v4l2_of_alloc_parse_endpoint()
+ * @endpoint - the endpoint the resources of which are to be released
+ *
+ * It is safe to call this function with NULL argument or on an
+ * endpoint the parsing of which failed.
+ */
+void v4l2_of_free_endpoint(struct v4l2_of_endpoint *endpoint)
+{
+	if (IS_ERR_OR_NULL(endpoint))
+		return;
+
+	kfree(endpoint->link_frequencies);
+	kfree(endpoint);
+}
+EXPORT_SYMBOL(v4l2_of_free_endpoint);
+
+/**
+ * v4l2_of_alloc_parse_endpoint() - parse all endpoint node properties
+ * @node: pointer to endpoint device_node
+ *
+ * All properties are optional. If none are found, we don't set any flags.
+ * This means the port has a static configuration and no properties have
+ * to be specified explicitly.
+ * If any properties that identify the bus as parallel are found and
+ * slave-mode isn't set, we set V4L2_MBUS_MASTER. Similarly, if we recognise
+ * the bus as serial CSI-2 and clock-noncontinuous isn't set, we set the
+ * V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag.
+ * The caller should hold a reference to @node.
+ *
+ * v4l2_of_alloc_parse_endpoint() has two important differences to
+ * v4l2_of_parse_endpoint():
+ *
+ * 1. It also parses variable size data and
+ *
+ * 2. The memory it has allocated to store the variable size data must
+ *    be freed using v4l2_of_free_endpoint() when no longer needed.
+ *
+ * Return: Pointer to v4l2_of_endpoint if successful, on error a
+ * negative error code.
+ */
+struct v4l2_of_endpoint *v4l2_of_alloc_parse_endpoint(
+	const struct device_node *node)
+{
+	struct v4l2_of_endpoint *endpoint;
+	int len;
+	int rval;
+
+	endpoint = kzalloc(sizeof(*endpoint), GFP_KERNEL);
+	if (!endpoint)
+		return ERR_PTR(-ENOMEM);
+
+	rval = v4l2_of_parse_endpoint(node, endpoint);
+	if (rval < 0)
+		goto out_err;
+
+	if (of_get_property(node, "link-frequencies", &len)) {
+		endpoint->link_frequencies = kmalloc(len, GFP_KERNEL);
+		if (!endpoint->link_frequencies) {
+			rval = -ENOMEM;
+			goto out_err;
+		}
+
+		endpoint->nr_of_link_frequencies =
+			len / sizeof(*endpoint->link_frequencies);
+
+		rval = of_property_read_u64_array(
+			node, "link-frequencies", endpoint->link_frequencies,
+			endpoint->nr_of_link_frequencies);
+		if (rval < 0)
+			goto out_err;
+	}
+
+	return endpoint;
+
+out_err:
+	v4l2_of_free_endpoint(endpoint);
+	return ERR_PTR(rval);
+}
+EXPORT_SYMBOL(v4l2_of_alloc_parse_endpoint);
+
 /**
  * v4l2_of_parse_link() - parse a link between two endpoints
  * @node: pointer to the endpoint at the local end of the link
diff --git a/include/media/v4l2-of.h b/include/media/v4l2-of.h
index 6c85c07..241e98a 100644
--- a/include/media/v4l2-of.h
+++ b/include/media/v4l2-of.h
@@ -57,6 +57,8 @@ struct v4l2_of_bus_parallel {
  * @base: struct of_endpoint containing port, id, and local of_node
  * @bus_type: bus type
  * @bus: bus configuration data structure
+ * @link_frequencies: array of supported link frequencies
+ * @nr_of_link_frequencies: number of elements in link_frequenccies array
  */
 struct v4l2_of_endpoint {
 	struct of_endpoint base;
@@ -66,6 +68,8 @@ struct v4l2_of_endpoint {
 		struct v4l2_of_bus_parallel parallel;
 		struct v4l2_of_bus_mipi_csi2 mipi_csi2;
 	} bus;
+	u64 *link_frequencies;
+	unsigned int nr_of_link_frequencies;
 };
 
 /**
@@ -85,6 +89,9 @@ struct v4l2_of_link {
 #ifdef CONFIG_OF
 int v4l2_of_parse_endpoint(const struct device_node *node,
 			   struct v4l2_of_endpoint *endpoint);
+struct v4l2_of_endpoint *v4l2_of_alloc_parse_endpoint(
+	const struct device_node *node);
+void v4l2_of_free_endpoint(struct v4l2_of_endpoint *endpoint);
 int v4l2_of_parse_link(const struct device_node *node,
 		       struct v4l2_of_link *link);
 void v4l2_of_put_link(struct v4l2_of_link *link);
@@ -96,6 +103,16 @@ static inline int v4l2_of_parse_endpoint(const struct device_node *node,
 	return -ENOSYS;
 }
 
+struct v4l2_of_endpoint *v4l2_of_alloc_parse_endpoint(
+	const struct device_node *node)
+{
+	return NULL;
+}
+
+static void v4l2_of_free_endpoint(struct v4l2_of_endpoint *endpoint)
+{
+}
+
 static inline int v4l2_of_parse_link(const struct device_node *node,
 				     struct v4l2_of_link *link)
 {
-- 
1.7.10.4

[PATCH v4 4/4] smiapp: Use v4l2_of_alloc_parse_endpoint()

[Sakari Ailus]

Instead of parsing the link-frequencies property in the driver, let
v4l2_of_alloc_parse_endpoint() do it.

Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 drivers/media/i2c/smiapp/smiapp-core.c |   40 ++++++++++++++++----------------
 1 file changed, 20 insertions(+), 20 deletions(-)

diff --git a/drivers/media/i2c/smiapp/smiapp-core.c b/drivers/media/i2c/smiapp/smiapp-core.c
index 557f25d..4a2e8d3 100644
--- a/drivers/media/i2c/smiapp/smiapp-core.c
+++ b/drivers/media/i2c/smiapp/smiapp-core.c
@@ -2975,9 +2975,9 @@ static int smiapp_resume(struct device *dev)
 static struct smiapp_platform_data *smiapp_get_pdata(struct device *dev)
 {
 	struct smiapp_platform_data *pdata;
-	struct v4l2_of_endpoint bus_cfg;
+	struct v4l2_of_endpoint *bus_cfg;
 	struct device_node *ep;
-	uint32_t asize;
+	int i;
 	int rval;
 
 	if (!dev->of_node)
@@ -2987,13 +2987,17 @@ static struct smiapp_platform_data *smiapp_get_pdata(struct device *dev)
 	if (!ep)
 		return NULL;
 
+	bus_cfg = v4l2_of_alloc_parse_endpoint(ep);
+	if (IS_ERR(bus_cfg)) {
+		rval = PTR_ERR(bus_cfg);
+		goto out_err;
+	}
+
 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
 	if (!pdata)
 		goto out_err;
 
-	v4l2_of_parse_endpoint(ep, &bus_cfg);
-
-	switch (bus_cfg.bus_type) {
+	switch (bus_cfg->bus_type) {
 	case V4L2_MBUS_CSI2:
 		pdata->csi_signalling_mode = SMIAPP_CSI_SIGNALLING_MODE_CSI2;
 		break;
@@ -3002,7 +3006,7 @@ static struct smiapp_platform_data *smiapp_get_pdata(struct device *dev)
 		goto out_err;
 	}
 
-	pdata->lanes = bus_cfg.bus.mipi_csi2.num_data_lanes;
+	pdata->lanes = bus_cfg->bus.mipi_csi2.num_data_lanes;
 	dev_dbg(dev, "lanes %u\n", pdata->lanes);
 
 	/* xshutdown GPIO is optional */
@@ -3022,34 +3026,30 @@ static struct smiapp_platform_data *smiapp_get_pdata(struct device *dev)
 	dev_dbg(dev, "reset %d, nvm %d, clk %d, csi %d\n", pdata->xshutdown,
 		pdata->nvm_size, pdata->ext_clk, pdata->csi_signalling_mode);
 
-	rval = of_get_property(ep, "link-frequencies", &asize) ? 0 : -ENOENT;
-	if (rval) {
-		dev_warn(dev, "can't get link-frequencies array size\n");
+	if (!bus_cfg->nr_of_link_frequencies) {
+		dev_warn(dev, "no link frequencies defined\n");
 		goto out_err;
 	}
 
-	pdata->op_sys_clock = devm_kzalloc(dev, asize, GFP_KERNEL);
+	pdata->op_sys_clock = devm_kcalloc(
+		dev, bus_cfg->nr_of_link_frequencies + 1 /* guardian */,
+		sizeof(*pdata->op_sys_clock), GFP_KERNEL);
 	if (!pdata->op_sys_clock) {
 		rval = -ENOMEM;
 		goto out_err;
 	}
 
-	asize /= sizeof(*pdata->op_sys_clock);
-	rval = of_property_read_u64_array(
-		ep, "link-frequencies", pdata->op_sys_clock, asize);
-	if (rval) {
-		dev_warn(dev, "can't get link-frequencies\n");
-		goto out_err;
+	for (i = 0; i < bus_cfg->nr_of_link_frequencies; i++) {
+		pdata->op_sys_clock[i] = bus_cfg->link_frequencies[i];
+		dev_dbg(dev, "freq %d: %lld\n", i, pdata->op_sys_clock[i]);
 	}
 
-	for (; asize > 0; asize--)
-		dev_dbg(dev, "freq %d: %lld\n", asize - 1,
-			pdata->op_sys_clock[asize - 1]);
-
+	v4l2_of_free_endpoint(bus_cfg);
 	of_node_put(ep);
 	return pdata;
 
 out_err:
+	v4l2_of_free_endpoint(bus_cfg);
 	of_node_put(ep);
 	return NULL;
 }
-- 
1.7.10.4

Re: [PATCH v4 1/4] v4l: of: Remove the head field in struct v4l2_of_endpoint

[Sylwester Nawrocki]

Hi Sakari,

On 09/04/15 23:25, Sakari Ailus wrote:
> The field is unused. Remove it.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
> ---
>  include/media/v4l2-of.h |    2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/include/media/v4l2-of.h b/include/media/v4l2-of.h
> index f831c9c..f66b92c 100644
> --- a/include/media/v4l2-of.h
> +++ b/include/media/v4l2-of.h
> @@ -57,7 +57,6 @@ struct v4l2_of_bus_parallel {
>   * @base: struct of_endpoint containing port, id, and local of_node
>   * @bus_type: bus type
>   * @bus: bus configuration data structure
> - * @head: list head for this structure
>   */
>  struct v4l2_of_endpoint {
>  	struct of_endpoint base;
> @@ -66,7 +65,6 @@ struct v4l2_of_endpoint {
>  		struct v4l2_of_bus_parallel parallel;
>  		struct v4l2_of_bus_mipi_csi2 mipi_csi2;
>  	} bus;
> -	struct list_head head;
>  };

I don't remember what this list_head was originally intended for,
probably for some code in soc_camera on which didn't the works were
postponed or abandoned. Presumably now such code would likely live
in drivers/of/base.c anyway.

Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>

-- 
Regards,
Sylwester

Re: [PATCH v4 2/4] v4l: of: Instead of zeroing bus_type and bus field separately, unify this

[Sylwester Nawrocki]

On 09/04/15 23:25, Sakari Ailus wrote:
> Zero the entire struct starting from bus_type. As more fields are added, no
> changes will be needed in the function to reset their value explicitly.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>

Re: [PATCH v4 3/4] v4l: of: Parse variable length properties --- link-frequencies

[Sylwester Nawrocki]

On 09/04/15 23:25, Sakari Ailus wrote:
> The link-frequencies property is a variable length array of link frequencies
> in an endpoint. The array is needed by an increasing number of drivers, so
> it makes sense to add it to struct v4l2_of_endpoint.
> 
> However, the length of the array is variable and the size of struct
> v4l2_of_endpoint is fixed since it is allocated by the caller. The options
> here are
> 
> 1. to define a fixed maximum limit of link frequencies that has to be the
> global maximum of all boards. This is seen as problematic since the maximum
> could be largish, and everyone hitting the problem would need to submit a
> patch to fix it, or
> 
> 2. parse the property in every driver. This doesn't sound appealing as two
> of the three implementations submitted to linux-media were wrong, and one of
> them was even merged before this was noticed, or
> 
> 3. change the interface so that allocating and releasing memory according to
> the size of the array is possible. This is what the patch does.
> 
> v4l2_of_alloc_parse_endpoint() is just like v4l2_of_parse_endpoint(), but it
> will allocate the memory resources needed to store struct v4l2_of_endpoint
> and the additional arrays pointed to by this struct. A corresponding release
> function v4l2_of_free_endpoint() is provided to release the memory allocated
> by v4l2_of_alloc_parse_endpoint().
> 
> In addition to this, the link-frequencies property is parsed as well, and
> the result is stored to struct v4l2_of_endpoint field link_frequencies.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

It's a bit sad we need to introduce the ERR_PTR() patter, nevertheless
I can't see a better alternative now. I think in long term we need to
get rid of v4l2_of_parse_endpoint() function.

Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>

-- 
Regards,
Sylwester

Re: [PATCH v4 4/4] smiapp: Use v4l2_of_alloc_parse_endpoint()

[Sylwester Nawrocki]

On 09/04/15 23:25, Sakari Ailus wrote:
> Instead of parsing the link-frequencies property in the driver, let
> v4l2_of_alloc_parse_endpoint() do it.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>

Re: [PATCH v4 4/4] smiapp: Use v4l2_of_alloc_parse_endpoint()

[Lad, Prabhakar]

Hi Sakari,

Thanks for the patch.

On Thu, Apr 9, 2015 at 10:25 PM, Sakari Ailus <sakari.ailus@iki.fi> wrote:
> Instead of parsing the link-frequencies property in the driver, let
> v4l2_of_alloc_parse_endpoint() do it.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
>  drivers/media/i2c/smiapp/smiapp-core.c |   40 ++++++++++++++++----------------
>  1 file changed, 20 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/media/i2c/smiapp/smiapp-core.c b/drivers/media/i2c/smiapp/smiapp-core.c
> index 557f25d..4a2e8d3 100644
> --- a/drivers/media/i2c/smiapp/smiapp-core.c
> +++ b/drivers/media/i2c/smiapp/smiapp-core.c
> @@ -2975,9 +2975,9 @@ static int smiapp_resume(struct device *dev)
>  static struct smiapp_platform_data *smiapp_get_pdata(struct device *dev)
>  {
>         struct smiapp_platform_data *pdata;
> -       struct v4l2_of_endpoint bus_cfg;
> +       struct v4l2_of_endpoint *bus_cfg;
>         struct device_node *ep;
> -       uint32_t asize;
> +       int i;
>         int rval;
>
>         if (!dev->of_node)
> @@ -2987,13 +2987,17 @@ static struct smiapp_platform_data *smiapp_get_pdata(struct device *dev)
>         if (!ep)
>                 return NULL;
>
> +       bus_cfg = v4l2_of_alloc_parse_endpoint(ep);
> +       if (IS_ERR(bus_cfg)) {
> +               rval = PTR_ERR(bus_cfg);

this assignment  is not required.

Apart from that the patch looks good.

Reviewed-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>

Cheers,
--Prabhakar Lad

Re: [PATCH v4 4/4] smiapp: Use v4l2_of_alloc_parse_endpoint()

[Sakari Ailus]

Hi Prabhakar,

Thank you for the review.

On Fri, Apr 10, 2015 at 10:54:08PM +0100, Lad, Prabhakar wrote:
> Hi Sakari,
> 
> Thanks for the patch.
> 
> On Thu, Apr 9, 2015 at 10:25 PM, Sakari Ailus <sakari.ailus@iki.fi> wrote:
> > Instead of parsing the link-frequencies property in the driver, let
> > v4l2_of_alloc_parse_endpoint() do it.
> >
> > Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
> > Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > ---
> >  drivers/media/i2c/smiapp/smiapp-core.c |   40 ++++++++++++++++----------------
> >  1 file changed, 20 insertions(+), 20 deletions(-)
> >
> > diff --git a/drivers/media/i2c/smiapp/smiapp-core.c b/drivers/media/i2c/smiapp/smiapp-core.c
> > index 557f25d..4a2e8d3 100644
> > --- a/drivers/media/i2c/smiapp/smiapp-core.c
> > +++ b/drivers/media/i2c/smiapp/smiapp-core.c
> > @@ -2975,9 +2975,9 @@ static int smiapp_resume(struct device *dev)
> >  static struct smiapp_platform_data *smiapp_get_pdata(struct device *dev)
> >  {
> >         struct smiapp_platform_data *pdata;
> > -       struct v4l2_of_endpoint bus_cfg;
> > +       struct v4l2_of_endpoint *bus_cfg;
> >         struct device_node *ep;
> > -       uint32_t asize;
> > +       int i;
> >         int rval;
> >
> >         if (!dev->of_node)
> > @@ -2987,13 +2987,17 @@ static struct smiapp_platform_data *smiapp_get_pdata(struct device *dev)
> >         if (!ep)
> >                 return NULL;
> >
> > +       bus_cfg = v4l2_of_alloc_parse_endpoint(ep);
> > +       if (IS_ERR(bus_cfg)) {
> > +               rval = PTR_ERR(bus_cfg);
> 
> this assignment  is not required.
> 
> Apart from that the patch looks good.
> 
> Reviewed-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>

Good point. I'll remove it.

There's another case of the same in the function, I'll send a separate patch
on that. I'll send a pull request on these soonish.

-- 
Kind regards,

Sakari Ailus
e-mail: sakari.ailus@iki.fi	XMPP: sailus@retiisi.org.uk

Re: [PATCH v4 3/4] v4l: of: Parse variable length properties --- link-frequencies

[Lad, Prabhakar]

Hi Sakari,

Thanks for the patch.

On Thu, Apr 9, 2015 at 10:25 PM, Sakari Ailus <sakari.ailus@iki.fi> wrote:
> The link-frequencies property is a variable length array of link frequencies
> in an endpoint. The array is needed by an increasing number of drivers, so
> it makes sense to add it to struct v4l2_of_endpoint.
>
> However, the length of the array is variable and the size of struct
> v4l2_of_endpoint is fixed since it is allocated by the caller. The options
> here are
>
> 1. to define a fixed maximum limit of link frequencies that has to be the
> global maximum of all boards. This is seen as problematic since the maximum
> could be largish, and everyone hitting the problem would need to submit a
> patch to fix it, or
>
> 2. parse the property in every driver. This doesn't sound appealing as two
> of the three implementations submitted to linux-media were wrong, and one of
> them was even merged before this was noticed, or
>
> 3. change the interface so that allocating and releasing memory according to
> the size of the array is possible. This is what the patch does.
>
> v4l2_of_alloc_parse_endpoint() is just like v4l2_of_parse_endpoint(), but it
> will allocate the memory resources needed to store struct v4l2_of_endpoint
> and the additional arrays pointed to by this struct. A corresponding release
> function v4l2_of_free_endpoint() is provided to release the memory allocated
> by v4l2_of_alloc_parse_endpoint().
>
> In addition to this, the link-frequencies property is parsed as well, and
> the result is stored to struct v4l2_of_endpoint field link_frequencies.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Tested-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>

Cheers,
--Prabhakar Lad

> ---
>  drivers/media/v4l2-core/v4l2-of.c |   87 +++++++++++++++++++++++++++++++++++++
>  include/media/v4l2-of.h           |   17 ++++++++
>  2 files changed, 104 insertions(+)
>
> diff --git a/drivers/media/v4l2-core/v4l2-of.c b/drivers/media/v4l2-core/v4l2-of.c
> index 3ac6348..c52fb96 100644
> --- a/drivers/media/v4l2-core/v4l2-of.c
> +++ b/drivers/media/v4l2-core/v4l2-of.c
> @@ -14,6 +14,7 @@
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
> +#include <linux/slab.h>
>  #include <linux/string.h>
>  #include <linux/types.h>
>
> @@ -141,6 +142,10 @@ static void v4l2_of_parse_parallel_bus(const struct device_node *node,
>   * V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag.
>   * The caller should hold a reference to @node.
>   *
> + * NOTE: This function does not parse properties the size of which is
> + * variable without a low fixed limit. Please use
> + * v4l2_of_alloc_parse_endpoint() in new drivers instead.
> + *
>   * Return: 0.
>   */
>  int v4l2_of_parse_endpoint(const struct device_node *node,
> @@ -167,6 +172,88 @@ int v4l2_of_parse_endpoint(const struct device_node *node,
>  }
>  EXPORT_SYMBOL(v4l2_of_parse_endpoint);
>
> +/*
> + * v4l2_of_free_endpoint() - free the endpoint acquired by
> + * v4l2_of_alloc_parse_endpoint()
> + * @endpoint - the endpoint the resources of which are to be released
> + *
> + * It is safe to call this function with NULL argument or on an
> + * endpoint the parsing of which failed.
> + */
> +void v4l2_of_free_endpoint(struct v4l2_of_endpoint *endpoint)
> +{
> +       if (IS_ERR_OR_NULL(endpoint))
> +               return;
> +
> +       kfree(endpoint->link_frequencies);
> +       kfree(endpoint);
> +}
> +EXPORT_SYMBOL(v4l2_of_free_endpoint);
> +
> +/**
> + * v4l2_of_alloc_parse_endpoint() - parse all endpoint node properties
> + * @node: pointer to endpoint device_node
> + *
> + * All properties are optional. If none are found, we don't set any flags.
> + * This means the port has a static configuration and no properties have
> + * to be specified explicitly.
> + * If any properties that identify the bus as parallel are found and
> + * slave-mode isn't set, we set V4L2_MBUS_MASTER. Similarly, if we recognise
> + * the bus as serial CSI-2 and clock-noncontinuous isn't set, we set the
> + * V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag.
> + * The caller should hold a reference to @node.
> + *
> + * v4l2_of_alloc_parse_endpoint() has two important differences to
> + * v4l2_of_parse_endpoint():
> + *
> + * 1. It also parses variable size data and
> + *
> + * 2. The memory it has allocated to store the variable size data must
> + *    be freed using v4l2_of_free_endpoint() when no longer needed.
> + *
> + * Return: Pointer to v4l2_of_endpoint if successful, on error a
> + * negative error code.
> + */
> +struct v4l2_of_endpoint *v4l2_of_alloc_parse_endpoint(
> +       const struct device_node *node)
> +{
> +       struct v4l2_of_endpoint *endpoint;
> +       int len;
> +       int rval;
> +
> +       endpoint = kzalloc(sizeof(*endpoint), GFP_KERNEL);
> +       if (!endpoint)
> +               return ERR_PTR(-ENOMEM);
> +
> +       rval = v4l2_of_parse_endpoint(node, endpoint);
> +       if (rval < 0)
> +               goto out_err;
> +
> +       if (of_get_property(node, "link-frequencies", &len)) {
> +               endpoint->link_frequencies = kmalloc(len, GFP_KERNEL);
> +               if (!endpoint->link_frequencies) {
> +                       rval = -ENOMEM;
> +                       goto out_err;
> +               }
> +
> +               endpoint->nr_of_link_frequencies =
> +                       len / sizeof(*endpoint->link_frequencies);
> +
> +               rval = of_property_read_u64_array(
> +                       node, "link-frequencies", endpoint->link_frequencies,
> +                       endpoint->nr_of_link_frequencies);
> +               if (rval < 0)
> +                       goto out_err;
> +       }
> +
> +       return endpoint;
> +
> +out_err:
> +       v4l2_of_free_endpoint(endpoint);
> +       return ERR_PTR(rval);
> +}
> +EXPORT_SYMBOL(v4l2_of_alloc_parse_endpoint);
> +
>  /**
>   * v4l2_of_parse_link() - parse a link between two endpoints
>   * @node: pointer to the endpoint at the local end of the link
> diff --git a/include/media/v4l2-of.h b/include/media/v4l2-of.h
> index 6c85c07..241e98a 100644
> --- a/include/media/v4l2-of.h
> +++ b/include/media/v4l2-of.h
> @@ -57,6 +57,8 @@ struct v4l2_of_bus_parallel {
>   * @base: struct of_endpoint containing port, id, and local of_node
>   * @bus_type: bus type
>   * @bus: bus configuration data structure
> + * @link_frequencies: array of supported link frequencies
> + * @nr_of_link_frequencies: number of elements in link_frequenccies array
>   */
>  struct v4l2_of_endpoint {
>         struct of_endpoint base;
> @@ -66,6 +68,8 @@ struct v4l2_of_endpoint {
>                 struct v4l2_of_bus_parallel parallel;
>                 struct v4l2_of_bus_mipi_csi2 mipi_csi2;
>         } bus;
> +       u64 *link_frequencies;
> +       unsigned int nr_of_link_frequencies;
>  };
>
>  /**
> @@ -85,6 +89,9 @@ struct v4l2_of_link {
>  #ifdef CONFIG_OF
>  int v4l2_of_parse_endpoint(const struct device_node *node,
>                            struct v4l2_of_endpoint *endpoint);
> +struct v4l2_of_endpoint *v4l2_of_alloc_parse_endpoint(
> +       const struct device_node *node);
> +void v4l2_of_free_endpoint(struct v4l2_of_endpoint *endpoint);
>  int v4l2_of_parse_link(const struct device_node *node,
>                        struct v4l2_of_link *link);
>  void v4l2_of_put_link(struct v4l2_of_link *link);
> @@ -96,6 +103,16 @@ static inline int v4l2_of_parse_endpoint(const struct device_node *node,
>         return -ENOSYS;
>  }
>
> +struct v4l2_of_endpoint *v4l2_of_alloc_parse_endpoint(
> +       const struct device_node *node)
> +{
> +       return NULL;
> +}
> +
> +static void v4l2_of_free_endpoint(struct v4l2_of_endpoint *endpoint)
> +{
> +}
> +
>  static inline int v4l2_of_parse_link(const struct device_node *node,
>                                      struct v4l2_of_link *link)
>  {
> --
> 1.7.10.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-media" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v4.1 4/4] smiapp: Use v4l2_of_alloc_parse_endpoint()

[Sakari Ailus]

Instead of parsing the link-frequencies property in the driver, let
v4l2_of_alloc_parse_endpoint() do it.

Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
---
since v4:

- Remove useless assignment to rval.

 drivers/media/i2c/smiapp/smiapp-core.c |   38 +++++++++++++++-----------------
 1 file changed, 18 insertions(+), 20 deletions(-)

diff --git a/drivers/media/i2c/smiapp/smiapp-core.c b/drivers/media/i2c/smiapp/smiapp-core.c
index 557f25d..636ebd6 100644
--- a/drivers/media/i2c/smiapp/smiapp-core.c
+++ b/drivers/media/i2c/smiapp/smiapp-core.c
@@ -2975,9 +2975,9 @@ static int smiapp_resume(struct device *dev)
 static struct smiapp_platform_data *smiapp_get_pdata(struct device *dev)
 {
 	struct smiapp_platform_data *pdata;
-	struct v4l2_of_endpoint bus_cfg;
+	struct v4l2_of_endpoint *bus_cfg;
 	struct device_node *ep;
-	uint32_t asize;
+	int i;
 	int rval;
 
 	if (!dev->of_node)
@@ -2987,13 +2987,15 @@ static struct smiapp_platform_data *smiapp_get_pdata(struct device *dev)
 	if (!ep)
 		return NULL;
 
+	bus_cfg = v4l2_of_alloc_parse_endpoint(ep);
+	if (IS_ERR(bus_cfg))
+		goto out_err;
+
 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
 	if (!pdata)
 		goto out_err;
 
-	v4l2_of_parse_endpoint(ep, &bus_cfg);
-
-	switch (bus_cfg.bus_type) {
+	switch (bus_cfg->bus_type) {
 	case V4L2_MBUS_CSI2:
 		pdata->csi_signalling_mode = SMIAPP_CSI_SIGNALLING_MODE_CSI2;
 		break;
@@ -3002,7 +3004,7 @@ static struct smiapp_platform_data *smiapp_get_pdata(struct device *dev)
 		goto out_err;
 	}
 
-	pdata->lanes = bus_cfg.bus.mipi_csi2.num_data_lanes;
+	pdata->lanes = bus_cfg->bus.mipi_csi2.num_data_lanes;
 	dev_dbg(dev, "lanes %u\n", pdata->lanes);
 
 	/* xshutdown GPIO is optional */
@@ -3022,34 +3024,30 @@ static struct smiapp_platform_data *smiapp_get_pdata(struct device *dev)
 	dev_dbg(dev, "reset %d, nvm %d, clk %d, csi %d\n", pdata->xshutdown,
 		pdata->nvm_size, pdata->ext_clk, pdata->csi_signalling_mode);
 
-	rval = of_get_property(ep, "link-frequencies", &asize) ? 0 : -ENOENT;
-	if (rval) {
-		dev_warn(dev, "can't get link-frequencies array size\n");
+	if (!bus_cfg->nr_of_link_frequencies) {
+		dev_warn(dev, "no link frequencies defined\n");
 		goto out_err;
 	}
 
-	pdata->op_sys_clock = devm_kzalloc(dev, asize, GFP_KERNEL);
+	pdata->op_sys_clock = devm_kcalloc(
+		dev, bus_cfg->nr_of_link_frequencies + 1 /* guardian */,
+		sizeof(*pdata->op_sys_clock), GFP_KERNEL);
 	if (!pdata->op_sys_clock) {
 		rval = -ENOMEM;
 		goto out_err;
 	}
 
-	asize /= sizeof(*pdata->op_sys_clock);
-	rval = of_property_read_u64_array(
-		ep, "link-frequencies", pdata->op_sys_clock, asize);
-	if (rval) {
-		dev_warn(dev, "can't get link-frequencies\n");
-		goto out_err;
+	for (i = 0; i < bus_cfg->nr_of_link_frequencies; i++) {
+		pdata->op_sys_clock[i] = bus_cfg->link_frequencies[i];
+		dev_dbg(dev, "freq %d: %lld\n", i, pdata->op_sys_clock[i]);
 	}
 
-	for (; asize > 0; asize--)
-		dev_dbg(dev, "freq %d: %lld\n", asize - 1,
-			pdata->op_sys_clock[asize - 1]);
-
+	v4l2_of_free_endpoint(bus_cfg);
 	of_node_put(ep);
 	return pdata;
 
 out_err:
+	v4l2_of_free_endpoint(bus_cfg);
 	of_node_put(ep);
 	return NULL;
 }
-- 
1.7.10.4

Re: [PATCH v4 2/4] v4l: of: Instead of zeroing bus_type and bus field separately, unify this

[Lad, Prabhakar]

Hi Sakari,

Thanks for the patch.

On Thu, Apr 9, 2015 at 10:25 PM, Sakari Ailus <sakari.ailus@iki.fi> wrote:
> Zero the entire struct starting from bus_type. As more fields are added, no
> changes will be needed in the function to reset their value explicitly.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Acked-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>

Cheers,
--Prabhakar Lad

> ---
>  drivers/media/v4l2-core/v4l2-of.c |    5 +++--
>  include/media/v4l2-of.h           |    1 +
>  2 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-of.c b/drivers/media/v4l2-core/v4l2-of.c
> index 83143d3..3ac6348 100644
> --- a/drivers/media/v4l2-core/v4l2-of.c
> +++ b/drivers/media/v4l2-core/v4l2-of.c
> @@ -149,8 +149,9 @@ int v4l2_of_parse_endpoint(const struct device_node *node,
>         int rval;
>
>         of_graph_parse_endpoint(node, &endpoint->base);
> -       endpoint->bus_type = 0;
> -       memset(&endpoint->bus, 0, sizeof(endpoint->bus));
> +       /* Zero fields from bus_type to until the end */
> +       memset(&endpoint->bus_type, 0, sizeof(*endpoint) -
> +              offsetof(typeof(*endpoint), bus_type));
>
>         rval = v4l2_of_parse_csi_bus(node, endpoint);
>         if (rval)
> diff --git a/include/media/v4l2-of.h b/include/media/v4l2-of.h
> index f66b92c..6c85c07 100644
> --- a/include/media/v4l2-of.h
> +++ b/include/media/v4l2-of.h
> @@ -60,6 +60,7 @@ struct v4l2_of_bus_parallel {
>   */
>  struct v4l2_of_endpoint {
>         struct of_endpoint base;
> +       /* Fields below this line will be zeroed by v4l2_of_parse_endpoint() */
>         enum v4l2_mbus_type bus_type;
>         union {
>                 struct v4l2_of_bus_parallel parallel;
> --
> 1.7.10.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-media" in
> the body of a message to majordomo@vger.kernel.org
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Re: [PATCH v4 1/4] v4l: of: Remove the head field in struct v4l2_of_endpoint

[Sakari Ailus]

Hi Sylwester,

On Fri, Apr 10, 2015 at 11:47:20AM +0200, Sylwester Nawrocki wrote:
> Hi Sakari,
> 
> On 09/04/15 23:25, Sakari Ailus wrote:
> > The field is unused. Remove it.
> > 
> > Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
> > ---
> >  include/media/v4l2-of.h |    2 --
> >  1 file changed, 2 deletions(-)
> > 
> > diff --git a/include/media/v4l2-of.h b/include/media/v4l2-of.h
> > index f831c9c..f66b92c 100644
> > --- a/include/media/v4l2-of.h
> > +++ b/include/media/v4l2-of.h
> > @@ -57,7 +57,6 @@ struct v4l2_of_bus_parallel {
> >   * @base: struct of_endpoint containing port, id, and local of_node
> >   * @bus_type: bus type
> >   * @bus: bus configuration data structure
> > - * @head: list head for this structure
> >   */
> >  struct v4l2_of_endpoint {
> >  	struct of_endpoint base;
> > @@ -66,7 +65,6 @@ struct v4l2_of_endpoint {
> >  		struct v4l2_of_bus_parallel parallel;
> >  		struct v4l2_of_bus_mipi_csi2 mipi_csi2;
> >  	} bus;
> > -	struct list_head head;
> >  };
> 
> I don't remember what this list_head was originally intended for,
> probably for some code in soc_camera on which didn't the works were
> postponed or abandoned. Presumably now such code would likely live
> in drivers/of/base.c anyway.

I thought something like that might have happened. I wasn't involved with
this at the time so I didn't remember... should have been a separate patch
though.

> Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>

Many thanks for the review!

-- 
Kind regards,

Sakari Ailus
e-mail: sakari.ailus@iki.fi	XMPP: sailus@retiisi.org.uk