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    Subject[PATCH RFC 09/13] media: add a V4L2 OF parser
    Date
    From: Guennadi Liakhovetski <g.liakhovetski@gmx.de>

    Add a V4L2 OF parser, implementing bindings, documented in
    Documentation/devicetree/bindings/media/v4l2.txt.

    Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
    ---
    drivers/media/v4l2-core/Makefile | 3 +
    drivers/media/v4l2-core/v4l2-of.c | 190 +++++++++++++++++++++++++++++++++++++
    include/media/v4l2-of.h | 62 ++++++++++++
    3 files changed, 255 insertions(+)
    create mode 100644 drivers/media/v4l2-core/v4l2-of.c
    create mode 100644 include/media/v4l2-of.h

    diff --git a/drivers/media/v4l2-core/Makefile b/drivers/media/v4l2-core/Makefile
    index c2d61d4..00f64d6 100644
    --- a/drivers/media/v4l2-core/Makefile
    +++ b/drivers/media/v4l2-core/Makefile
    @@ -9,6 +9,9 @@ videodev-objs := v4l2-dev.o v4l2-ioctl.o v4l2-device.o v4l2-fh.o \
    ifeq ($(CONFIG_COMPAT),y)
    videodev-objs += v4l2-compat-ioctl32.o
    endif
    +ifeq ($(CONFIG_OF),y)
    + videodev-objs += v4l2-of.o
    +endif

    obj-$(CONFIG_VIDEO_DEV) += videodev.o v4l2-int-device.o
    obj-$(CONFIG_VIDEO_V4L2) += v4l2-common.o
    diff --git a/drivers/media/v4l2-core/v4l2-of.c b/drivers/media/v4l2-core/v4l2-of.c
    new file mode 100644
    index 0000000..f45d64b
    --- /dev/null
    +++ b/drivers/media/v4l2-core/v4l2-of.c
    @@ -0,0 +1,190 @@
    +/*
    + * V4L2 OF binding parsing library
    + *
    + * Copyright (C) 2012 Renesas Electronics Corp.
    + * Author: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
    + *
    + * 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/kernel.h>
    +#include <linux/module.h>
    +#include <linux/of.h>
    +#include <linux/types.h>
    +
    +#include <media/v4l2-of.h>
    +
    +/*
    + * 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 are found, that identify the bus as parallel, 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."
    + */
    +void v4l2_of_parse_link(const struct device_node *node,
    + struct v4l2_of_link *link)
    +{
    + const struct device_node *port_node = of_get_parent(node);
    + int size;
    + unsigned int v;
    + u32 data_lanes[ARRAY_SIZE(link->mipi_csi_2.data_lanes)];
    + bool data_lanes_present;
    +
    + memset(link, 0, sizeof(*link));
    +
    + link->local_node = node;
    +
    + /* Doesn't matter, whether the below two calls succeed */
    + of_property_read_u32(port_node, "reg", &link->port);
    + of_property_read_u32(node, "reg", &link->addr);
    +
    + if (!of_property_read_u32(node, "bus-width", &v))
    + link->parallel.bus_width = v;
    +
    + if (!of_property_read_u32(node, "data-shift", &v))
    + link->parallel.data_shift = v;
    +
    + if (!of_property_read_u32(node, "hsync-active", &v))
    + link->mbus_flags |= v ? V4L2_MBUS_HSYNC_ACTIVE_HIGH :
    + V4L2_MBUS_HSYNC_ACTIVE_LOW;
    +
    + if (!of_property_read_u32(node, "vsync-active", &v))
    + link->mbus_flags |= v ? V4L2_MBUS_VSYNC_ACTIVE_HIGH :
    + V4L2_MBUS_VSYNC_ACTIVE_LOW;
    +
    + if (!of_property_read_u32(node, "data-active", &v))
    + link->mbus_flags |= v ? V4L2_MBUS_DATA_ACTIVE_HIGH :
    + V4L2_MBUS_DATA_ACTIVE_LOW;
    +
    + if (!of_property_read_u32(node, "pclk-sample", &v))
    + link->mbus_flags |= v ? V4L2_MBUS_PCLK_SAMPLE_RISING :
    + V4L2_MBUS_PCLK_SAMPLE_FALLING;
    +
    + if (!of_property_read_u32(node, "field-even-active", &v))
    + link->mbus_flags |= v ? V4L2_MBUS_FIELD_EVEN_HIGH :
    + V4L2_MBUS_FIELD_EVEN_LOW;
    +
    + if (of_get_property(node, "slave-mode", &size))
    + link->mbus_flags |= V4L2_MBUS_SLAVE;
    +
    + /* If any parallel-bus properties have been found, skip serial ones */
    + if (link->parallel.bus_width || link->parallel.data_shift ||
    + link->mbus_flags) {
    + /* Default parallel bus-master */
    + if (!(link->mbus_flags & V4L2_MBUS_SLAVE))
    + link->mbus_flags |= V4L2_MBUS_MASTER;
    + return;
    + }
    +
    + if (!of_property_read_u32(node, "clock-lanes", &v))
    + link->mipi_csi_2.clock_lane = v;
    +
    + if (!of_property_read_u32_array(node, "data-lanes", data_lanes,
    + ARRAY_SIZE(data_lanes))) {
    + int i;
    + for (i = 0; i < ARRAY_SIZE(data_lanes); i++)
    + link->mipi_csi_2.data_lanes[i] = data_lanes[i];
    + data_lanes_present = true;
    + } else {
    + data_lanes_present = false;
    + }
    +
    + if (of_get_property(node, "clock-noncontinuous", &size))
    + link->mbus_flags |= V4L2_MBUS_CSI2_NONCONTINUOUS_CLOCK;
    +
    + if ((link->mipi_csi_2.clock_lane || data_lanes_present) &&
    + !(link->mbus_flags & V4L2_MBUS_CSI2_NONCONTINUOUS_CLOCK))
    + /* Default CSI-2: continuous clock */
    + link->mbus_flags |= V4L2_MBUS_CSI2_CONTINUOUS_CLOCK;
    +}
    +EXPORT_SYMBOL(v4l2_of_parse_link);
    +
    +/*
    + * Return a refcounted next "link" DT node. Contrary to the common OF practice,
    + * we do not drop the reference to previous, users have to do it themselves,
    + * when they're done with the node.
    + */
    +struct device_node *v4l2_of_get_next_link(const struct device_node *parent,
    + struct device_node *previous)
    +{
    + struct device_node *child, *port;
    +
    + if (!parent)
    + return NULL;
    +
    + if (!previous) {
    + /*
    + * If this is the first call, we have to find a port within this
    + * node
    + */
    + for_each_child_of_node(parent, port) {
    + if (!of_node_cmp(port->name, "port"))
    + break;
    + }
    + if (port) {
    + /* Found a port, get a link */
    + child = of_get_next_child(port, NULL);
    + of_node_put(port);
    + } else {
    + child = NULL;
    + }
    + if (!child)
    + pr_err("%s(): Invalid DT: %s has no link children!\n",
    + __func__, parent->name);
    + } else {
    + port = of_get_parent(previous);
    + if (!port)
    + /* Hm, has someone given us the root node?... */
    + return NULL;
    +
    + /* Avoid dropping previous refcount to 0 */
    + of_node_get(previous);
    + child = of_get_next_child(port, previous);
    + if (child) {
    + of_node_put(port);
    + return child;
    + }
    +
    + /* No more links under this port, try the next one */
    + do {
    + port = of_get_next_child(parent, port);
    + if (!port)
    + return NULL;
    + } while (of_node_cmp(port->name, "port"));
    +
    + /* Pick up the first link on this port */
    + child = of_get_next_child(port, NULL);
    + of_node_put(port);
    + }
    +
    + return child;
    +}
    +EXPORT_SYMBOL(v4l2_of_get_next_link);
    +
    +/* Return a refcounted DT node, owning the link, referenced by "remote" */
    +struct device_node *v4l2_of_get_remote(const struct device_node *node)
    +{
    + struct device_node *remote, *tmp;
    +
    + /* Get remote link DT node */
    + remote = of_parse_phandle(node, "remote", 0);
    + if (!remote)
    + return NULL;
    +
    + /* remote port */
    + tmp = of_get_parent(remote);
    + of_node_put(remote);
    + if (!tmp)
    + return NULL;
    +
    + /* remote DT node */
    + remote = of_get_parent(tmp);
    + of_node_put(tmp);
    +
    + return remote;
    +}
    +EXPORT_SYMBOL(v4l2_of_get_remote);
    diff --git a/include/media/v4l2-of.h b/include/media/v4l2-of.h
    new file mode 100644
    index 0000000..6fafedb
    --- /dev/null
    +++ b/include/media/v4l2-of.h
    @@ -0,0 +1,62 @@
    +/*
    + * V4L2 OF binding parsing library
    + *
    + * Copyright (C) 2012 Renesas Electronics Corp.
    + * Author: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
    + *
    + * 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_OF_H
    +#define _V4L2_OF_H
    +
    +#include <linux/list.h>
    +#include <linux/types.h>
    +
    +#include <media/v4l2-mediabus.h>
    +
    +struct device_node;
    +
    +struct v4l2_of_link {
    + unsigned int port;
    + unsigned int addr;
    + struct list_head head;
    + const struct device_node *local_node;
    + const __be32 *remote;
    + unsigned int mbus_flags;
    + union {
    + struct {
    + unsigned char bus_width;
    + unsigned char data_shift;
    + } parallel;
    + struct {
    + unsigned char data_lanes[4];
    + unsigned char clock_lane;
    + } mipi_csi_2;
    + };
    +};
    +
    +#ifdef CONFIG_OF
    +void v4l2_of_parse_link(const struct device_node *node,
    + struct v4l2_of_link *link);
    +struct device_node *v4l2_of_get_next_link(const struct device_node *parent,
    + struct device_node *previous);
    +struct device_node *v4l2_of_get_remote(const struct device_node *node);
    +#else
    +static inline void v4l2_of_parse_link(const struct device_node *node,
    + struct v4l2_of_link *link)
    +{
    +}
    +static inline struct device_node *v4l2_of_get_next_link(const struct device_node *parent,
    + struct device_node *previous)
    +{
    + return NULL;
    +}
    +static inline struct device_node *v4l2_of_get_remote(const struct device_node *node)
    +{
    + return NULL;
    +}
    +#endif
    +
    +#endif
    --
    1.7.9.5


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