[PATCH RFC v3 02/15] [media] Add a V4L2 OF parser
Sylwester Nawrocki
s.nawrocki at samsung.com
Sat Jan 19 02:48:43 EST 2013
On 01/03/2013 06:09 PM, Sylwester Nawrocki wrote:
> From: Guennadi Liakhovetski <g.liakhovetski at gmx.de>
>
> Add a V4L2 OF parser, implementing bindings documented in
> Documentation/devicetree/bindings/media/video-interfaces.txt.
>
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski at gmx.de>
> Signed-off-by: Sylwester Nawrocki <s.nawrocki at samsung.com>
Hans, Laurent, Mauro, would you have any comments on this ?
Anything that needs to be changed/improved ?
I'd like to send a pull request including this patch, together
with an updated patch series [1] (v3) adding initial device tree
support to the Exynos camera subsystem drivers.
[1] http://www.spinics.net/lists/linux-media/msg57947.html
Thanks,
Sylwester
> ---
> Changes since v2:
> - added missing EXPORT_SYMBOL for v4l2_of_parse_mipi_csi2()
> and v4l2_of_parse_parallel_bus() functions,
> - include string.h header instead of slab.h.
>
> drivers/media/v4l2-core/Makefile | 3 +
> drivers/media/v4l2-core/v4l2-of.c | 251 +++++++++++++++++++++++++++++++++++++
> include/media/v4l2-of.h | 79 ++++++++++++
> 3 files changed, 333 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..483245c
> --- /dev/null
> +++ b/drivers/media/v4l2-core/v4l2-of.c
> @@ -0,0 +1,251 @@
> +/*
> + * V4L2 OF binding parsing library
> + *
> + * Copyright (C) 2012 Renesas Electronics Corp.
> + * Author: Guennadi Liakhovetski <g.liakhovetski at 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/string.h>
> +#include <linux/types.h>
> +
> +#include <media/v4l2-of.h>
> +
> +/**
> + * v4l2_of_parse_mipi_csi2() - parse MIPI CSI-2 bus properties
> + * @node: pointer to endpoint device_node
> + * @endpoint: pointer to v4l2_of_endpoint data structure
> + *
> + * Return: 0 on success or negative error value otherwise.
> + */
> +int v4l2_of_parse_mipi_csi2(const struct device_node *node,
> + struct v4l2_of_endpoint *endpoint)
> +{
> + struct v4l2_of_mipi_csi2 *mipi_csi2 = &endpoint->mipi_csi_2;
> + u32 data_lanes[ARRAY_SIZE(mipi_csi2->data_lanes)];
> + struct property *prop;
> + const __be32 *lane = NULL;
> + u32 v;
> + int i = 0;
> +
> + prop = of_find_property(node, "data-lanes", NULL);
> + if (!prop)
> + return -EINVAL;
> + do {
> + lane = of_prop_next_u32(prop, lane, &data_lanes[i]);
> + } while (lane && i++ < ARRAY_SIZE(data_lanes));
> +
> + mipi_csi2->num_data_lanes = i;
> + while (i--)
> + mipi_csi2->data_lanes[i] = data_lanes[i];
> +
> + if (!of_property_read_u32(node, "clock-lanes", &v))
> + mipi_csi2->clock_lane = v;
> +
> + if (of_get_property(node, "clock-noncontinuous", &v))
> + endpoint->mbus_flags |= V4L2_MBUS_CSI2_NONCONTINUOUS_CLOCK;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(v4l2_of_parse_mipi_csi2);
> +
> +/**
> + * v4l2_of_parse_parallel_bus() - parse parallel bus properties
> + * @node: pointer to endpoint device_node
> + * @endpoint: pointer to v4l2_of_endpoint data structure
> + */
> +void v4l2_of_parse_parallel_bus(const struct device_node *node,
> + struct v4l2_of_endpoint *endpoint)
> +{
> + unsigned int flags = 0;
> + u32 v;
> +
> + if (WARN_ON(!endpoint))
> + return;
> +
> + if (!of_property_read_u32(node, "hsync-active", &v))
> + flags |= v ? V4L2_MBUS_HSYNC_ACTIVE_HIGH :
> + V4L2_MBUS_HSYNC_ACTIVE_LOW;
> +
> + if (!of_property_read_u32(node, "vsync-active", &v))
> + flags |= v ? V4L2_MBUS_VSYNC_ACTIVE_HIGH :
> + V4L2_MBUS_VSYNC_ACTIVE_LOW;
> +
> + if (!of_property_read_u32(node, "pclk-sample", &v))
> + flags |= v ? V4L2_MBUS_PCLK_SAMPLE_RISING :
> + V4L2_MBUS_PCLK_SAMPLE_FALLING;
> +
> + if (!of_property_read_u32(node, "field-even-active", &v))
> + flags |= v ? V4L2_MBUS_FIELD_EVEN_HIGH :
> + V4L2_MBUS_FIELD_EVEN_LOW;
> + if (flags)
> + endpoint->mbus_type = V4L2_MBUS_PARALLEL;
> + else
> + endpoint->mbus_type = V4L2_MBUS_BT656;
> +
> + if (!of_property_read_u32(node, "data-active", &v))
> + flags |= v ? V4L2_MBUS_DATA_ACTIVE_HIGH :
> + V4L2_MBUS_DATA_ACTIVE_LOW;
> +
> + if (of_get_property(node, "slave-mode", &v))
> + flags |= V4L2_MBUS_SLAVE;
> +
> + if (!of_property_read_u32(node, "bus-width", &v))
> + endpoint->parallel.bus_width = v;
> +
> + if (!of_property_read_u32(node, "data-shift", &v))
> + endpoint->parallel.data_shift = v;
> +
> + endpoint->mbus_flags = flags;
> +}
> +EXPORT_SYMBOL(v4l2_of_parse_parallel_bus);
> +
> +/**
> + * v4l2_of_parse_endpoint() - parse all endpoint node properties
> + * @node: pointer to endpoint device_node
> + * @endpoint: pointer to v4l2_of_endpoint 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.
> + */
> +void v4l2_of_parse_endpoint(const struct device_node *node,
> + struct v4l2_of_endpoint *endpoint)
> +{
> + const struct device_node *port_node = of_get_parent(node);
> + bool data_lanes_present = false;
> +
> + memset(endpoint, 0, sizeof(*endpoint));
> +
> + endpoint->local_node = node;
> +
> + /* Doesn't matter, whether the below two calls succeed */
> + of_property_read_u32(port_node, "reg", &endpoint->port);
> + of_property_read_u32(node, "reg", &endpoint->addr);
> +
> + v4l2_of_parse_parallel_bus(node, endpoint);
> +
> + /* If any parallel bus properties have been found, skip serial ones */
> + if (endpoint->parallel.bus_width || endpoint->parallel.data_shift ||
> + endpoint->mbus_flags) {
> + /* Default parallel bus-master */
> + if (!(endpoint->mbus_flags & V4L2_MBUS_SLAVE))
> + endpoint->mbus_flags |= V4L2_MBUS_MASTER;
> + return;
> + }
> +
> + endpoint->mbus_type = V4L2_MBUS_CSI2;
> +
> + if (!v4l2_of_parse_mipi_csi2(node, endpoint))
> + data_lanes_present = true;
> +
> + if ((endpoint->mipi_csi_2.clock_lane || data_lanes_present) &&
> + !(endpoint->mbus_flags & V4L2_MBUS_CSI2_NONCONTINUOUS_CLOCK)) {
> + /* Default CSI-2: continuous clock */
> + endpoint->mbus_flags |= V4L2_MBUS_CSI2_CONTINUOUS_CLOCK;
> + }
> +}
> +EXPORT_SYMBOL(v4l2_of_parse_endpoint);
> +
> +/*
> + * Return a refcounted next "endpoint" 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_endpoint(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_endpoint);
> +
> +/**
> + * v4l2_of_get_remote_port_parent() - get remote port's parent node
> + * @node: pointer to local endpoint device_node
> + *
> + * Return: Remote device node associated with remote endpoint node linked
> + * to @node. Use of_node_put() on it when done.
> + */
> +struct device_node *v4l2_of_get_remote_port_parent(
> + const struct device_node *node)
> +{
> + struct device_node *re, *tmp;
> +
> + /* Get remote endpoint DT node. */
> + re = of_parse_phandle(node, "remote-endpoint", 0);
> + if (!re)
> + return NULL;
> +
> + /* Remote port. */
> + tmp = of_get_parent(re);
> + of_node_put(re);
> + if (!tmp)
> + return NULL;
> +
> + /* Remote device node. */
> + re = of_get_parent(tmp);
> + of_node_put(tmp);
> +
> + return re;
> +}
> +EXPORT_SYMBOL(v4l2_of_get_remote_port_parent);
> diff --git a/include/media/v4l2-of.h b/include/media/v4l2-of.h
> new file mode 100644
> index 0000000..1aba3b3
> --- /dev/null
> +++ b/include/media/v4l2-of.h
> @@ -0,0 +1,79 @@
> +/*
> + * V4L2 OF binding parsing library
> + *
> + * Copyright (C) 2012 Renesas Electronics Corp.
> + * Author: Guennadi Liakhovetski <g.liakhovetski at 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 <linux/errno.h>
> +
> +#include <media/v4l2-mediabus.h>
> +
> +struct device_node;
> +
> +struct v4l2_of_mipi_csi2 {
> + unsigned char data_lanes[4];
> + unsigned char clock_lane;
> + unsigned short num_data_lanes;
> +};
> +
> +struct v4l2_of_endpoint {
> + unsigned int port;
> + unsigned int addr;
> + struct list_head head;
> + const struct device_node *local_node;
> + const __be32 *remote;
> + enum v4l2_mbus_type mbus_type;
> + unsigned int mbus_flags;
> + union {
> + struct {
> + unsigned char bus_width;
> + unsigned char data_shift;
> + } parallel;
> + struct v4l2_of_mipi_csi2 mipi_csi_2;
> + };
> +};
> +
> +#ifdef CONFIG_OF
> +int v4l2_of_parse_mipi_csi2(const struct device_node *node,
> + struct v4l2_of_endpoint *endpoint);
> +void v4l2_of_parse_parallel_bus(const struct device_node *node,
> + struct v4l2_of_endpoint *endpoint);
> +void v4l2_of_parse_endpoint(const struct device_node *node,
> + struct v4l2_of_endpoint *link);
> +struct device_node *v4l2_of_get_next_endpoint(const struct device_node *parent,
> + struct device_node *previous);
> +struct device_node *v4l2_of_get_remote_port_parent(
> + const struct device_node *node);
> +#else /* CONFIG_OF */
> +
> +static inline int v4l2_of_parse_endpoint(const struct device_node *node,
> + struct v4l2_of_endpoint *link)
> +{
> + return -ENOSYS;
> +}
> +
> +static inline struct device_node *v4l2_of_get_next_endpoint(
> + const struct device_node *parent,
> + struct device_node *previous)
> +{
> + return NULL;
> +}
> +
> +static inline struct device_node *v4l2_of_get_remote_endpoint(
> + const struct device_node *node)
> +{
> + return NULL;
> +}
> +
> +#endif /* CONFIG_OF */
> +
> +#endif /* _V4L2_OF_H */
> --
> 1.7.9.5
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