From 2e6e39324aecd10dbf66819b137a5ee73298b931 Mon Sep 17 00:00:00 2001 From: Sakari Ailus Date: Wed, 18 Jul 2018 06:09:57 -0400 Subject: 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 Tested-by: Steve Longerbeam Tested-by: Jacopo Mondi Signed-off-by: Mauro Carvalho Chehab --- include/media/v4l2-fwnode.h | 56 ++++++++++++++++++++++++++++++--------------- 1 file changed, 37 insertions(+), 19 deletions(-) (limited to 'include/media') diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h index 1ea1a3ecf6d5..b4a49ca27579 100644 --- a/include/media/v4l2-fwnode.h +++ b/include/media/v4l2-fwnode.h @@ -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. - * - * The caller must set the bus_type field of @vep to zero. + * 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. + * + * 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. + * + * 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 caller must set the bus_type field of @vep to zero. + * 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); -- cgit