Re: [PATCH v2 2/8] v4l: fwnode: Support generic fwnode for parsing standardised properties

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Hi Laurent,

On Fri, Apr 07, 2017 at 12:44:27PM +0300, Laurent Pinchart wrote:
> Hi Sakari,
> 
> Thank you for the patch.
> 
> On Thursday 06 Apr 2017 16:12:04 Sakari Ailus wrote:
> > The fwnode_handle is a more generic way than OF device_node to describe
> > firmware nodes. Instead of the OF API, use more generic fwnode API to
> > obtain the same information.
> 
> I would mention that this is a copy of v4l2-of.c with the OF API replaced with 
> the fwnode API.

I'll add that to the description.

> 
> > As the V4L2 fwnode support will be required by a small minority of e.g.
> > ACPI based systems (the same might actually go for OF), make this a module
> > instead of embedding it in the videodev module.
> > 
> > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> > ---
> >  drivers/media/v4l2-core/Kconfig       |   3 +
> >  drivers/media/v4l2-core/Makefile      |   1 +
> >  drivers/media/v4l2-core/v4l2-fwnode.c | 353 +++++++++++++++++++++++++++++++
> >  include/media/v4l2-fwnode.h           | 104 ++++++++++
> >  4 files changed, 461 insertions(+)
> >  create mode 100644 drivers/media/v4l2-core/v4l2-fwnode.c
> >  create mode 100644 include/media/v4l2-fwnode.h
> > 
> > diff --git a/drivers/media/v4l2-core/Kconfig
> > b/drivers/media/v4l2-core/Kconfig index 6b1b78f..a35c336 100644
> > --- a/drivers/media/v4l2-core/Kconfig
> > +++ b/drivers/media/v4l2-core/Kconfig
> > @@ -55,6 +55,9 @@ config V4L2_FLASH_LED_CLASS
> > 
> >  	  When in doubt, say N.
> > 
> > +config V4L2_FWNODE
> > +	tristate
> > +
> >  # Used by drivers that need Videobuf modules
> >  config VIDEOBUF_GEN
> >  	tristate
> > diff --git a/drivers/media/v4l2-core/Makefile
> > b/drivers/media/v4l2-core/Makefile index 795a535..cf77a63 100644
> > --- a/drivers/media/v4l2-core/Makefile
> > +++ b/drivers/media/v4l2-core/Makefile
> > @@ -13,6 +13,7 @@ endif
> >  ifeq ($(CONFIG_OF),y)
> >    videodev-objs += v4l2-of.o
> >  endif
> > +obj-$(CONFIG_V4L2_FWNODE) += v4l2-fwnode.o
> >  ifeq ($(CONFIG_TRACEPOINTS),y)
> >    videodev-objs += vb2-trace.o v4l2-trace.o
> >  endif
> > diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c
> > b/drivers/media/v4l2-core/v4l2-fwnode.c new file mode 100644
> > index 0000000..4f69b11
> > --- /dev/null
> > +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> > @@ -0,0 +1,353 @@
> > +/*
> > + * V4L2 fwnode binding parsing library
> > + *
> > + * Copyright (c) 2016 Intel Corporation.
> > + * Author: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> > + *
> > + * Copyright (C) 2012 - 2013 Samsung Electronics Co., Ltd.
> > + * Author: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
> > + *
> > + * Copyright (C) 2012 Renesas Electronics Corp.
> > + * Author: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of version 2 of the GNU General Public License as
> > + * published by the Free Software Foundation.
> > + */
> > +#include <linux/acpi.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/property.h>
> > +#include <linux/slab.h>
> > +#include <linux/string.h>
> > +#include <linux/types.h>
> > +
> > +#include <media/v4l2-fwnode.h>
> > +
> > +static int v4l2_fwnode_endpoint_parse_csi_bus(struct fwnode_handle *fwn,
> > +					      struct v4l2_fwnode_endpoint 
> *vfwn)
> > +{
> > +	struct v4l2_fwnode_bus_mipi_csi2 *bus = &vfwn->bus.mipi_csi2;
> > +	bool have_clk_lane = false;
> > +	unsigned int flags = 0, lanes_used = 0;
> > +	unsigned int i;
> > +	u32 v;
> > +	int rval;
> 
> I would have used "ret" instead of "rval" ;-)

I know. But

1) there's no established convention in the file and

2) "rval" has the benefit is easier to look up; one doesn't find a plethora
of "return something". Therefore it is better than "ret" for the purpose.

> 
> > +	rval = fwnode_property_read_u32_array(fwn, "data-lanes", NULL, 0);
> > +	if (rval > 0) {
> > +		u32 array[ARRAY_SIZE(bus->data_lanes)];
> > +
> > +		bus->num_data_lanes =
> > +			min_t(int, ARRAY_SIZE(bus->data_lanes), rval);
> > +
> > +		fwnode_property_read_u32_array(
> > +			fwn, "data-lanes", array, bus->num_data_lanes);
> 
> Is there anything wrong with the usual way to wrap code ?
> 
> 		fwnode_property_read_u32_array(fwn, "data-lanes", array,
> 					       bus->num_data_lanes);

I'll change the occurrences of that whenever feasible.

> 
> > +
> > +		for (i = 0; i < bus->num_data_lanes; i++) {
> > +			if (lanes_used & BIT(array[i]))
> > +				pr_warn("duplicated lane %u in data-lanes\n",
> > +					array[i]);
> > +			lanes_used |= BIT(array[i]);
> > +
> > +			bus->data_lanes[i] = array[i];
> > +		}
> > +	}
> > +
> > +	rval = fwnode_property_read_u32_array(fwn, "lane-polarities", NULL, 
> 0);
> > +	if (rval > 0) {
> > +		u32 array[ARRAY_SIZE(bus->lane_polarities)];
> > +
> > +		if (rval < 1 + bus->num_data_lanes /* clock + data */) {
> > +			pr_warn("too few lane-polarities entries (need %u, got 
> %u)\n",
> > +				1 + bus->num_data_lanes, rval);
> > +			return -EINVAL;
> > +		}
> > +
> > +		fwnode_property_read_u32_array(
> > +			fwn, "lane-polarities", array, 1 + bus-
> >num_data_lanes);
> 
> Ditto with
> 
> 		fwnode_property_read_u32_array(fwn, "lane-polarities", array,
> 					       1 + bus->num_data_lanes);
> 
> > +		for (i = 0; i < 1 + bus->num_data_lanes; i++)
> > +			bus->lane_polarities[i] = array[i];
> > +	}
> > +
> > +	if (!fwnode_property_read_u32(fwn, "clock-lanes", &v)) {
> > +		if (lanes_used & BIT(v))
> > +			pr_warn("duplicated lane %u in clock-lanes\n", v);
> > +		lanes_used |= BIT(v);
> > +
> > +		bus->clock_lane = v;
> > +		have_clk_lane = true;
> > +	}
> > +
> > +	if (fwnode_property_present(fwn, "clock-noncontinuous"))
> > +		flags |= V4L2_MBUS_CSI2_NONCONTINUOUS_CLOCK;
> > +	else if (have_clk_lane || bus->num_data_lanes > 0)
> > +		flags |= V4L2_MBUS_CSI2_CONTINUOUS_CLOCK;
> > +
> > +	bus->flags = flags;
> > +	vfwn->bus_type = V4L2_MBUS_CSI2;
> > +
> > +	return 0;
> > +}
> > +
> > +static void v4l2_fwnode_endpoint_parse_parallel_bus(
> > +	struct fwnode_handle *fwn, struct v4l2_fwnode_endpoint *vfwn)
> > +{
> > +	struct v4l2_fwnode_bus_parallel *bus = &vfwn->bus.parallel;
> > +	unsigned int flags = 0;
> > +	u32 v;
> > +
> > +	if (!fwnode_property_read_u32(fwn, "hsync-active", &v))
> > +		flags |= v ? V4L2_MBUS_HSYNC_ACTIVE_HIGH :
> > +			V4L2_MBUS_HSYNC_ACTIVE_LOW;
> > +
> > +	if (!fwnode_property_read_u32(fwn, "vsync-active", &v))
> > +		flags |= v ? V4L2_MBUS_VSYNC_ACTIVE_HIGH :
> > +			V4L2_MBUS_VSYNC_ACTIVE_LOW;
> > +
> > +	if (!fwnode_property_read_u32(fwn, "field-even-active", &v))
> > +		flags |= v ? V4L2_MBUS_FIELD_EVEN_HIGH :
> > +			V4L2_MBUS_FIELD_EVEN_LOW;
> > +	if (flags)
> > +		vfwn->bus_type = V4L2_MBUS_PARALLEL;
> > +	else
> > +		vfwn->bus_type = V4L2_MBUS_BT656;
> > +
> > +	if (!fwnode_property_read_u32(fwn, "pclk-sample", &v))
> > +		flags |= v ? V4L2_MBUS_PCLK_SAMPLE_RISING :
> > +			V4L2_MBUS_PCLK_SAMPLE_FALLING;
> > +
> > +	if (!fwnode_property_read_u32(fwn, "data-active", &v))
> > +		flags |= v ? V4L2_MBUS_DATA_ACTIVE_HIGH :
> > +			V4L2_MBUS_DATA_ACTIVE_LOW;
> > +
> > +	if (fwnode_property_present(fwn, "slave-mode"))
> > +		flags |= V4L2_MBUS_SLAVE;
> > +	else
> > +		flags |= V4L2_MBUS_MASTER;
> > +
> > +	if (!fwnode_property_read_u32(fwn, "bus-width", &v))
> > +		bus->bus_width = v;
> > +
> > +	if (!fwnode_property_read_u32(fwn, "data-shift", &v))
> > +		bus->data_shift = v;
> > +
> > +	if (!fwnode_property_read_u32(fwn, "sync-on-green-active", &v))
> > +		flags |= v ? V4L2_MBUS_VIDEO_SOG_ACTIVE_HIGH :
> > +			V4L2_MBUS_VIDEO_SOG_ACTIVE_LOW;
> > +
> > +	bus->flags = flags;
> > +
> > +}
> > +
> > +/**
> > + * v4l2_fwnode_endpoint_parse() - parse all fwnode node properties
> > + * @fwn: pointer to fwnode_handle
> 
> I would say "the endpoint's fwnode handle", or "pointer to the endpoint's 
> fwnode handle". Otherwise which fwnode handle should be passed won't be clear.

I prefer the latter.

> 
> > + * @vfwn: 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 @node.
> 
> s/@node/@fwn/
> 
> By the way, have you tried to compile the documentation ?

I have, but I may have made changes since that. I'll test that again before
submitting the next version.

> 
> > + *
> > + * 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.
> > + */
> > +int v4l2_fwnode_endpoint_parse(struct fwnode_handle *fwn,
> > +			       struct v4l2_fwnode_endpoint *vfwn)
> 
> Is there a specific reason not to keep the original parameter name "endpoint" 
> ? vfwn seems to stand for v4l2_fwnode, not v4l2_fwnode_endpoint. Same comment 
> for all other locations in this patch.

I'm ok with keeping endpoint.

> 
> > +{
> > +	int rval;
> > +
> > +	fwnode_graph_parse_endpoint(fwn, &vfwn->base);
> > +
> > +	/* Zero fields from bus_type to until the end */
> > +	memset(&vfwn->bus_type, 0, sizeof(*vfwn) -
> > +	       offsetof(typeof(*vfwn), bus_type));
> > +
> > +	rval = v4l2_fwnode_endpoint_parse_csi_bus(fwn, vfwn);
> > +	if (rval)
> > +		return rval;
> > +	/*
> > +	 * Parse the parallel video bus properties only if none
> > +	 * of the MIPI CSI-2 specific properties were found.
> > +	 */
> > +	if (vfwn->bus.mipi_csi2.flags == 0)
> > +		v4l2_fwnode_endpoint_parse_parallel_bus(fwn, vfwn);
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL(v4l2_fwnode_endpoint_parse);
> 
> According to Mauro in http://www.mail-archive.com/linux-media@xxxxxxxxxxxxxxx/msg110809.html you should use EXPORT_SYMBOL_GPL.

EXPORT_SYMBOL() was used by v4l2-of.c; I'll switch here.

> 
> > +
> > +/*
> > + * v4l2_fwnode_endpoint_free() - free the V4L2 fwnode acquired by
> > + * v4l2_fwnode_endpoint_alloc_parse()
> > + * @fwn - the V4L2 fwnode the resources of which are to be released
> 
> Mayeb "the V4L2 fwnode whose resources are to be released" ?
> 
> > + *
> > + * It is safe to call this function with NULL argument or on an
> 
> s/on an/on a/

Yes.

> 
> > + * V4L2 fwnode the parsing of which failed.
> 
> "whose parsing failed" ?

Any particular reason? Do you like "whose"? :-)

> 
> > + */
> > +void v4l2_fwnode_endpoint_free(struct v4l2_fwnode_endpoint *vfwn)
> > +{
> > +	if (IS_ERR_OR_NULL(vfwn))
> > +		return;
> > +
> > +	kfree(vfwn->link_frequencies);
> > +	kfree(vfwn);
> > +}
> > +EXPORT_SYMBOL(v4l2_fwnode_endpoint_free);
> > +
> > +/**
> > + * v4l2_fwnode_endpoint_alloc_parse() - parse all fwnode node properties
> > + * @node: pointer to fwnode_handle
> 
> s/@node/@fwn/
> 
> Here too, I would say "the endpoint's fwnode handle", or "pointer to the 
> endpoint's fwnode handle".

I'll use the latter.

> 
> > + *
> > + * 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.
> 
> s/@node/@fwn/

Will fix.

> 
> > + *
> > + * v4l2_fwnode_endpoint_alloc_parse() has two important differences to
> > + * v4l2_fwnode_endpoint_parse():
> > + *
> > + * 1. It also parses variable size data and
> 
> Nitpicking, a valid sentence doesn't end with "and$". You could write
> 
> 1. It also parses variable size data.
> 2. The memory it has allocated to store the variable size data must
>    be freed using v4l2_fwnode_endpoint_free() when no longer needed.

I prefer this one, will change.

> 
> or
> 
> 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_fwnode_endpoint_free() when no longer needed.
> 
> > + *
> > + * 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: Pointer to v4l2_fwnode_endpoint if successful, on error a
> > + * negative error code.
> 
> The function returns an error pointer on error.

Yes, I'll improve the documentation.

> 
> > + */
> > +struct v4l2_fwnode_endpoint *v4l2_fwnode_endpoint_alloc_parse(
> > +	struct fwnode_handle *fwn)
> > +{
> > +	struct v4l2_fwnode_endpoint *vfwn;
> > +	int rval;
> 
> ret ? :-)
> 
> > +
> > +	vfwn = kzalloc(sizeof(*vfwn), GFP_KERNEL);
> > +	if (!vfwn)
> > +		return ERR_PTR(-ENOMEM);
> > +
> > +	rval = v4l2_fwnode_endpoint_parse(fwn, vfwn);
> > +	if (rval < 0)
> > +		goto out_err;
> > +
> > +	rval = fwnode_property_read_u64_array(fwn, "link-frequencies",
> > +					      NULL, 0);
> > +
> 
> No need for a blank line.

Indeed.

> 
> > +	if (rval < 0)
> > +		goto out_err;
> > +
> > +	vfwn->link_frequencies =
> > +		kmalloc_array(rval, sizeof(*vfwn->link_frequencies),
> > +			      GFP_KERNEL);
> > +	if (!vfwn->link_frequencies) {
> > +		rval = -ENOMEM;
> > +		goto out_err;
> > +	}
> > +
> > +	vfwn->nr_of_link_frequencies = rval;
> > +
> > +	rval = fwnode_property_read_u64_array(
> > +		fwn, "link-frequencies", vfwn->link_frequencies,
> > +		vfwn->nr_of_link_frequencies);
> 
> 	rval = fwnode_property_read_u64_array(fwn, "link-frequencies",
> 					      vfwn->link_frequencies,
> 					      vfwn->nr_of_link_frequencies);
> 
> > +	if (rval < 0)
> > +		goto out_err;
> > +
> > +	return vfwn;
> > +
> > +out_err:
> > +	v4l2_fwnode_endpoint_free(vfwn);
> > +	return ERR_PTR(rval);
> > +}
> > +EXPORT_SYMBOL(v4l2_fwnode_endpoint_alloc_parse);
> > +
> > +/**
> > + * v4l2_fwnode_endpoint_parse_link() - parse a link between two endpoints
> > + * @node: pointer to the fwnode at the local end of the link
> 
> The parameter is called __fwn. I believe you should rename it to fwn, 
> otherwise the documentation will look weird.
> 
> As explained before, you should mention that this is an endpoint fwnode 
> handle.

Agreed.

> 
> > + * @link: pointer to the V4L2 fwnode link data structure
> > + *
> > + * Fill the link structure with the local and remote nodes and port
> > numbers.
> > + * The local_node and remote_node fields are set to point to the local and
> > + * remote port's parent nodes respectively (the port parent node being the
> > + * parent node of the port node if that node isn't a 'ports' node, or the
> > + * grand-parent node of the port node otherwise).
> > + *
> > + * A reference is taken to both the local and remote nodes, the caller
> > + * must use v4l2_fwnode_endpoint_put_link() to drop the references
> > + * when done with the link.
> 
> Just curious, is there a reason to wrap earlier than the 80 columns limit ?
> 
>  * A reference is taken to both the local and remote nodes, the caller must 
> use 
>  * v4l2_fwnode_endpoint_put_link() to drop the references when done with the
>  * link.
> 
> would work.

It is like a speed limit, you can perfectly legally drive slower than 80
characters per line, right? :-)

Albeit the conditions seem pretty good in this file, I can try pushing it
closer to the limit.

> 
> > + * Return: 0 on success, or -ENOLINK if the remote fwnode can't be found.
> 
> Here too you should mention remote endpoint.

Oh yes.

> 
> > + */
> > +int v4l2_fwnode_parse_link(struct fwnode_handle *__fwn,
> > +			   struct v4l2_fwnode_link *link)
> > +{
> > +	struct fwnode_handle *fwn;
> > +	const char *port_prop = is_of_node(__fwn) ? "reg" : "port";
> > +
> > +	memset(link, 0, sizeof(*link));
> > +
> > +	fwn = fwnode_get_parent(__fwn);
> > +	fwnode_property_read_u32(fwn, port_prop, &link->local_port);
> > +	fwn = fwnode_get_next_parent(fwn);
> > +	if (is_of_node(fwn)) {
> > +		if (of_node_cmp(to_of_node(fwn)->name, "ports") == 0)
> > +			fwn = fwnode_get_next_parent(fwn);
> > +	} else {
> > +		/* The "ports" node is always there in ACPI. */
> > +		fwn = fwnode_get_next_parent(fwn);
> > +	}
> 
> To avoid duplicating the fwnode_get_next_parent(fwn) call, you could write
> 
> 	if (!is_of_node(fwn) ||
> 	    of_node_cmp(to_of_node(fwn)->name, "ports") == 0) {
> 		/* The "ports" node is always there in ACPI. */
> 		fwn = fwnode_get_next_parent(fwn);
> 	}

Will change.

> 
> > +	link->local_node = fwn;
> > +
> > +	fwn = fwnode_graph_get_remote_endpoint(fwn);
> > +	if (!fwn) {
> > +		fwnode_handle_put(fwn);
> > +		return -ENOLINK;
> > +	}
> > +
> > +	fwn = fwnode_get_parent(fwn);
> > +	fwnode_property_read_u32(fwn, port_prop, &link->remote_port);
> > +	fwn = fwnode_get_next_parent(fwn);
> > +	if (is_of_node(fwn)) {
> > +		if (of_node_cmp(to_of_node(fwn)->name, "ports") == 0)
> > +			fwn = fwnode_get_next_parent(fwn);
> > +	} else {
> > +		/* The "ports" node is always there in ACPI. */
> > +		fwn = fwnode_get_next_parent(fwn);
> > +	}
> 
> Same comment here.
> 
> > +	link->remote_node = fwn;
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL(v4l2_fwnode_parse_link);
> > +
> > +/**
> > + * v4l2_fwnode_put_link() - drop references to nodes in a link
> > + * @link: pointer to the V4L2 fwnode link data structure
> > + *
> > + * Drop references to the local and remote nodes in the link. This
> > + * function must be called on every link parsed with
> > + * v4l2_fwnode_parse_link().
> > + */
> > +void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link)
> > +{
> > +	fwnode_handle_put(link->local_node);
> > +	fwnode_handle_put(link->remote_node);
> > +}
> > +EXPORT_SYMBOL(v4l2_fwnode_put_link);
> > +
> > +MODULE_LICENSE("GPL");
> > +MODULE_AUTHOR("Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>");
> > +MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>");
> > +MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@xxxxxx>");
> > diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
> > new file mode 100644
> > index 0000000..a675d8a
> > --- /dev/null
> > +++ b/include/media/v4l2-fwnode.h
> > @@ -0,0 +1,104 @@
> > +/*
> > + * V4L2 fwnode binding parsing library
> > + *
> > + * Copyright (c) 2016 Intel Corporation.
> > + * Author: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> > + *
> > + * Copyright (C) 2012 - 2013 Samsung Electronics Co., Ltd.
> > + * Author: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
> > + *
> > + * Copyright (C) 2012 Renesas Electronics Corp.
> > + * Author: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of version 2 of the GNU General Public License as
> > + * published by the Free Software Foundation.
> > + */
> > +#ifndef _V4L2_FWNODE_H
> > +#define _V4L2_FWNODE_H
> > +
> > +#include <linux/list.h>
> > +#include <linux/types.h>
> > +#include <linux/errno.h>
> > +#include <linux/of_graph.h>
> 
> Alphabetical order please.

Yes.

> 
> > +#include <media/v4l2-mediabus.h>
> > +
> > +struct fwnode_handle;
> > +
> > +/**
> > + * struct v4l2_fwnode_bus_mipi_csi2 - MIPI CSI-2 bus data structure
> > + * @flags: media bus (V4L2_MBUS_*) flags
> > + * @data_lanes: an array of physical data lane indexes
> > + * @clock_lane: physical lane index of the clock lane
> > + * @num_data_lanes: number of data lanes
> > + * @lane_polarities: polarity of the lanes. The order is the same of
> > + *		   the physical lanes.
> > + */
> > +struct v4l2_fwnode_bus_mipi_csi2 {
> > +	unsigned int flags;
> > +	unsigned char data_lanes[4];
> > +	unsigned char clock_lane;
> > +	unsigned short num_data_lanes;
> > +	bool lane_polarities[5];
> > +};
> > +
> > +/**
> > + * struct v4l2_fwnode_bus_parallel - parallel data bus data structure
> > + * @flags: media bus (V4L2_MBUS_*) flags
> > + * @bus_width: bus width in bits
> > + * @data_shift: data shift in bits
> > + */
> > +struct v4l2_fwnode_bus_parallel {
> > +	unsigned int flags;
> > +	unsigned char bus_width;
> > +	unsigned char data_shift;
> > +};
> > +
> > +/**
> > + * struct v4l2_fwnode_endpoint - the endpoint data structure
> > + * @base: fwnode endpoint of the v4l2_fwnode
> > + * @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_fwnode_endpoint {
> > +	struct fwnode_endpoint base;
> > +	/*
> > +	 * Fields below this line will be zeroed by
> > +	 * v4l2_fwnode_parse_endpoint()
> > +	 */
> > +	enum v4l2_mbus_type bus_type;
> > +	union {
> > +		struct v4l2_fwnode_bus_parallel parallel;
> > +		struct v4l2_fwnode_bus_mipi_csi2 mipi_csi2;
> > +	} bus;
> > +	u64 *link_frequencies;
> > +	unsigned int nr_of_link_frequencies;
> > +};
> > +
> > +/**
> > + * struct v4l2_fwnode_link - a link between two endpoints
> > + * @local_node: pointer to device_node of this endpoint
> > + * @local_port: identifier of the port this endpoint belongs to
> > + * @remote_node: pointer to device_node of the remote endpoint
> > + * @remote_port: identifier of the port the remote endpoint belongs to
> > + */
> > +struct v4l2_fwnode_link {
> > +	struct fwnode_handle *local_node;
> > +	unsigned int local_port;
> > +	struct fwnode_handle *remote_node;
> > +	unsigned int remote_port;
> > +};
> > +
> > +int v4l2_fwnode_endpoint_parse(struct fwnode_handle *fwn,
> > +			       struct v4l2_fwnode_endpoint *vfwn);
> > +struct v4l2_fwnode_endpoint *v4l2_fwnode_endpoint_alloc_parse(
> > +	struct fwnode_handle *fwn);
> > +void v4l2_fwnode_endpoint_free(struct v4l2_fwnode_endpoint *vfwn);
> > +int v4l2_fwnode_parse_link(struct fwnode_handle *fwn,
> > +			   struct v4l2_fwnode_link *link);
> > +void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link);
> > +
> > +#endif /* _V4L2_FWNODE_H */
> 

-- 
Regards,

Sakari Ailus
e-mail: sakari.ailus@xxxxxx	XMPP: sailus@xxxxxxxxxxxxxx



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