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media: v4l: fwnode: Update V4L2 fwnode endpoint parsing documentation 

The semantics of v4l2_fwnode_endpoint_parse() and
v4l2_fwnode_endpoint_alloc_parse() have changed slightly: they now take
the bus type from the user as well as a default configuration for the bus
that shall reflect the DT binding defaults. Document this.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: Steve Longerbeam <steve_longerbeam@mentor.com>
Tested-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
This commit is contained in:
Sakari Ailus 2018-07-18 06:09:57 -04:00 committed by Mauro Carvalho Chehab
parent edc6d56c2e
commit 2e6e39324a
1 changed files with 36 additions and 18 deletions
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54
include/media/v4l2-fwnode.h
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@ -131,21 +131,30 @@ struct v4l2_fwnode_link {
* @fwnode: pointer to the endpoint's fwnode handle
* @vep: pointer to the V4L2 fwnode data structure
*
* 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 @fwnode.
* This function parses the V4L2 fwnode endpoint specific parameters from the
* firmware. The caller is responsible for assigning @vep.bus_type to a valid
* media bus type. The caller may also set the default configuration for the
* endpoint --- a configuration that shall be in line with the DT binding
* documentation. Should a device support multiple bus types, the caller may
* call this function once the correct type is found --- with a default
* configuration valid for that type.
*
* The caller must set the bus_type field of @vep to zero.
* As a compatibility means guessing the bus type is also supported by setting
* @vep.bus_type to V4L2_MBUS_UNKNOWN. The caller may not provide a default
* configuration in this case as the defaults are specific to a given bus type.
* This functionality is deprecated and should not be used in new drivers and it
* is only supported for CSI-2 D-PHY, parallel and Bt.656 busses.
*
* The function does not change the V4L2 fwnode endpoint state if it fails.
*
* NOTE: This function does not parse properties the size of which is variable
* without a low fixed limit. Please use v4l2_fwnode_endpoint_alloc_parse() in
* new drivers instead.
*
* Return: 0 on success or a negative error code on failure.
* Return: %0 on success or a negative error code on failure:
* %-ENOMEM on memory allocation failure
* %-EINVAL on parsing failure
* %-ENXIO on mismatching bus types
*/
int v4l2_fwnode_endpoint_parse(struct fwnode_handle *fwnode,
struct v4l2_fwnode_endpoint *vep);
@ -165,15 +174,21 @@ void v4l2_fwnode_endpoint_free(struct v4l2_fwnode_endpoint *vep);
* @fwnode: pointer to the endpoint's fwnode handle
* @vep: pointer to the V4L2 fwnode data structure
*
* 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 @fwnode.
* This function parses the V4L2 fwnode endpoint specific parameters from the
* firmware. The caller is responsible for assigning @vep.bus_type to a valid
* media bus type. The caller may also set the default configuration for the
* endpoint --- a configuration that shall be in line with the DT binding
* documentation. Should a device support multiple bus types, the caller may
* call this function once the correct type is found --- with a default
* configuration valid for that type.
*
* The caller must set the bus_type field of @vep to zero.
* As a compatibility means guessing the bus type is also supported by setting
* @vep.bus_type to V4L2_MBUS_UNKNOWN. The caller may not provide a default
* configuration in this case as the defaults are specific to a given bus type.
* This functionality is deprecated and should not be used in new drivers and it
* is only supported for CSI-2 D-PHY, parallel and Bt.656 busses.
*
* The function does not change the V4L2 fwnode endpoint state if it fails.
*
* v4l2_fwnode_endpoint_alloc_parse() has two important differences to
* v4l2_fwnode_endpoint_parse():
@ -183,7 +198,10 @@ void v4l2_fwnode_endpoint_free(struct v4l2_fwnode_endpoint *vep);
* 2. The memory it has allocated to store the variable size data must be freed
* using v4l2_fwnode_endpoint_free() when no longer needed.
*
* Return: 0 on success or a negative error code on failure.
* Return: %0 on success or a negative error code on failure:
* %-ENOMEM on memory allocation failure
* %-EINVAL on parsing failure
* %-ENXIO on mismatching bus types
*/
int v4l2_fwnode_endpoint_alloc_parse(
struct fwnode_handle *fwnode, struct v4l2_fwnode_endpoint *vep);