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

[Sakari Ailus <sakari.ailus-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>]

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.

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-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
---
 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-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
+ *
+ * Copyright (C) 2012 - 2013 Samsung Electronics Co., Ltd.
+ * Author: Sylwester Nawrocki <s.nawrocki-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
+ *
+ * Copyright (C) 2012 Renesas Electronics Corp.
+ * Author: Guennadi Liakhovetski <g.liakhovetski-Mmb7MZpHnFY@public.gmane.org>
+ *
+ * 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;
+
+	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);
+
+		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);
+
+		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
+ * @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.
+ *
+ * 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)
+{
+	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);
+
+/*
+ * 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
+ *
+ * It is safe to call this function with NULL argument or on an
+ * V4L2 fwnode the parsing of which failed.
+ */
+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
+ *
+ * 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.
+ *
+ * v4l2_fwnode_endpoint_alloc_parse() has two important differences to
+ * v4l2_fwnode_endpoint_parse():
+ *
+ * 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.
+ *
+ * Return: Pointer to v4l2_fwnode_endpoint if successful, on error a
+ * negative error code.
+ */
+struct v4l2_fwnode_endpoint *v4l2_fwnode_endpoint_alloc_parse(
+	struct fwnode_handle *fwn)
+{
+	struct v4l2_fwnode_endpoint *vfwn;
+	int rval;
+
+	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);
+
+	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);
+	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
+ * @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.
+ *
+ * Return: 0 on success, or -ENOLINK if the remote fwnode can't be found.
+ */
+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);
+	}
+	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);
+	}
+	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-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>");
+MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>");
+MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski-Mmb7MZpHnFY@public.gmane.org>");
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-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
+ *
+ * Copyright (C) 2012 - 2013 Samsung Electronics Co., Ltd.
+ * Author: Sylwester Nawrocki <s.nawrocki-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
+ *
+ * Copyright (C) 2012 Renesas Electronics Corp.
+ * Author: Guennadi Liakhovetski <g.liakhovetski-Mmb7MZpHnFY@public.gmane.org>
+ *
+ * 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>
+
+#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 */
-- 
2.7.4

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