The internal LVDS encoders now have their own DT bindings. Before
switching the driver infrastructure to those new bindings, implement
backward-compatibility through live DT patching.

Patching is disabled and will be enabled along with support for the new
DT bindings in the DU driver.

Signed-off-by: Laurent Pinchart <laurent.pinchart+rene...@ideasonboard.com>
---
 drivers/gpu/drm/rcar-du/Kconfig             |   1 +
 drivers/gpu/drm/rcar-du/Makefile            |   2 +
 drivers/gpu/drm/rcar-du/rcar_du_of.c        | 440 ++++++++++++++++++++++++++++
 drivers/gpu/drm/rcar-du/rcar_du_of.h        |  16 +
 drivers/gpu/drm/rcar-du/rcar_du_of_lvds.dts |  82 ++++++
 5 files changed, 541 insertions(+)
 create mode 100644 drivers/gpu/drm/rcar-du/rcar_du_of.c
 create mode 100644 drivers/gpu/drm/rcar-du/rcar_du_of.h
 create mode 100644 drivers/gpu/drm/rcar-du/rcar_du_of_lvds.dts

diff --git a/drivers/gpu/drm/rcar-du/Kconfig b/drivers/gpu/drm/rcar-du/Kconfig
index 8a50dab19e5c..e3193ebd3ced 100644
--- a/drivers/gpu/drm/rcar-du/Kconfig
+++ b/drivers/gpu/drm/rcar-du/Kconfig
@@ -22,6 +22,7 @@ config DRM_RCAR_LVDS
        bool "R-Car DU LVDS Encoder Support"
        depends on DRM_RCAR_DU
        select DRM_PANEL
+       select OF_OVERLAY
        help
          Enable support for the R-Car Display Unit embedded LVDS encoders.
 
diff --git a/drivers/gpu/drm/rcar-du/Makefile b/drivers/gpu/drm/rcar-du/Makefile
index 0cf5c11030e8..0cf457bef1f2 100644
--- a/drivers/gpu/drm/rcar-du/Makefile
+++ b/drivers/gpu/drm/rcar-du/Makefile
@@ -5,6 +5,8 @@ rcar-du-drm-y := rcar_du_crtc.o \
                 rcar_du_group.o \
                 rcar_du_kms.o \
                 rcar_du_lvdscon.o \
+                rcar_du_of.o \
+                rcar_du_of_lvds.dtb.o \
                 rcar_du_plane.o
 
 rcar-du-drm-$(CONFIG_DRM_RCAR_LVDS)    += rcar_du_lvdsenc.o
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_of.c 
b/drivers/gpu/drm/rcar-du/rcar_du_of.c
new file mode 100644
index 000000000000..c2726e29bd59
--- /dev/null
+++ b/drivers/gpu/drm/rcar-du/rcar_du_of.c
@@ -0,0 +1,440 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * rcar_du_of.c - Legacy DT bindings compatibility
+ *
+ * Copyright (C) 2018 Laurent Pinchart <laurent.pinch...@ideasonboard.com>
+ *
+ * Based on work from Jyri Sarha <jsa...@ti.com>
+ * Copyright (C) 2015 Texas Instruments
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_fdt.h>
+#include <linux/of_graph.h>
+#include <linux/slab.h>
+
+#include "rcar_du_crtc.h"
+#include "rcar_du_drv.h"
+
+extern u8 __dtb_rcar_du_of_lvds_begin[];
+extern u8 __dtb_rcar_du_of_lvds_end[];
+
+struct rcar_du_of_overlay {
+       struct device_node *np;
+       void *data;
+       void *mem;
+};
+
+static void __init rcar_du_of_free_overlay(struct rcar_du_of_overlay *overlay)
+{
+       of_node_put(overlay->np);
+       kfree(overlay->data);
+       kfree(overlay->mem);
+}
+
+static int __init rcar_du_of_get_overlay(struct rcar_du_of_overlay *overlay,
+                                        u8 *begin, u8 *end)
+{
+       const size_t size = end - begin;
+
+       memset(overlay, 0, sizeof(*overlay));
+
+       if (!size)
+               return -EINVAL;
+
+       overlay->data = kmemdup(begin, size, GFP_KERNEL);
+       if (!overlay->data)
+               return -ENOMEM;
+
+       overlay->mem = of_fdt_unflatten_tree(overlay->data, NULL, &overlay->np);
+       if (!overlay->mem) {
+               rcar_du_of_free_overlay(overlay);
+               return -ENOMEM;
+       }
+
+       return 0;
+}
+
+static struct device_node __init *
+rcar_du_of_find_node_by_path(struct device_node *parent, const char *path)
+{
+       parent = of_node_get(parent);
+       if (!parent)
+               return NULL;
+
+       while (parent && *path == '/') {
+               struct device_node *child = NULL;
+               struct device_node *node;
+               const char *next;
+               size_t len;
+
+               /* Skip the initial '/' delimiter and find the next one. */
+               path++;
+               next = strchrnul(path, '/');
+               len = next - path;
+               if (!len)
+                       goto error;
+
+               for_each_child_of_node(parent, node) {
+                       const char *name = kbasename(node->full_name);
+
+                       if (strncmp(path, name, len) == 0 &&
+                           strlen(name) == len) {
+                               child = node;
+                               break;
+                       }
+               }
+
+               if (!child)
+                       goto error;
+
+               of_node_put(parent);
+               parent = child;
+               path = next;
+       }
+
+       return parent;
+
+error:
+       of_node_put(parent);
+       return NULL;
+}
+
+static int __init rcar_du_of_add_property(struct device_node *np,
+                                         const char *name, const void *value,
+                                         size_t length)
+{
+       struct property *prop;
+
+       prop = kzalloc(sizeof(*prop), GFP_KERNEL);
+       if (!prop)
+               return -ENOMEM;
+
+       prop->name = kstrdup(name, GFP_KERNEL);
+       prop->value = kmemdup(value, length, GFP_KERNEL);
+       prop->length = length;
+
+       if (!prop->name || !prop->value) {
+               kfree(prop->name);
+               kfree(prop->value);
+               kfree(prop);
+               return -ENOMEM;
+       }
+
+       of_property_set_flag(prop, OF_DYNAMIC);
+
+       prop->next = np->properties;
+       np->properties = prop;
+
+       return 0;
+}
+
+/* Free properties allocated dynamically by rcar_du_of_add_property(). */
+static void __init rcar_du_of_free_properties(struct device_node *np)
+{
+       while (np->properties) {
+               struct property *prop = np->properties;
+
+               np->properties = prop->next;
+
+               if (OF_IS_DYNAMIC(prop)) {
+                       kfree(prop->name);
+                       kfree(prop->value);
+                       kfree(prop);
+               }
+       }
+}
+
+static int __init rcar_du_of_update_target_path(struct device_node *du,
+                                               struct device_node *remote,
+                                               struct device_node *np)
+{
+       struct device_node *target = NULL;
+       struct property **prev;
+       struct property *prop;
+       char *path;
+       int ret;
+
+       for (prop = np->properties, prev = &prop; prop != NULL;
+            prev = &prop->next, prop = prop->next) {
+               if (of_prop_cmp(prop->name, "target-path"))
+                       continue;
+
+               if (!of_prop_cmp(prop->value, "soc")) {
+                       target = of_get_parent(du);
+                       break;
+               }
+               if (!of_prop_cmp(prop->value, "du")) {
+                       target = of_node_get(du);
+                       break;
+               }
+               if (!of_prop_cmp(prop->value, "lvds-sink")) {
+                       target = of_graph_get_port_parent(remote);
+                       break;
+               }
+
+               return -EINVAL;
+       }
+
+       if (!target)
+               return -EINVAL;
+
+       path = kasprintf(GFP_KERNEL, "%pOF", target);
+       of_node_put(target);
+       if (!path)
+               return -ENOMEM;
+
+       /*
+        * Remove the existing target-path property that has not been
+        * dynamically allocated and replace it with a new dynamic one to
+        * ensure that the value will be properly freed.
+        */
+       *prev = prop->next;
+       ret = rcar_du_of_add_property(np, "target-path", path,
+                                     strlen(path) + 1);
+       if (ret < 0) {
+               kfree(path);
+               return ret;
+       }
+
+       return 0;
+}
+
+static void __init rcar_du_of_lvds_patch_one(struct device_node *du,
+                                            unsigned int port_id,
+                                            const struct resource *res,
+                                            const __be32 *reg,
+                                            const struct of_phandle_args 
*clkspec,
+                                            struct device_node *local,
+                                            struct device_node *remote)
+{
+       struct rcar_du_of_overlay overlay;
+       struct device_node *du_port, *du_port_fixup;
+       struct device_node *lvds_endpoints[2];
+       struct device_node *lvds;
+       struct device_node *fragment;
+       struct property *prop;
+       const char *compatible;
+       const char *soc_suffix;
+       unsigned int psize;
+       unsigned int i;
+       __be32 value[4];
+       char name[23];
+       int ovcs_id;
+       int ret;
+
+       /* Skip if the LVDS node already exists. */
+       sprintf(name, "lvds@%llx", (u64)res->start);
+       lvds = of_get_child_by_name(du->parent, name);
+       if (lvds) {
+               of_node_put(lvds);
+               return;
+       }
+
+       /* Parse the overlay. */
+       ret = rcar_du_of_get_overlay(&overlay, __dtb_rcar_du_of_lvds_begin,
+                                    __dtb_rcar_du_of_lvds_end);
+       if (ret < 0)
+               return;
+
+       /*
+        * Patch the LVDS and DU port nodes names and the associated fixup
+        * entries.
+        */
+       lvds = rcar_du_of_find_node_by_path(overlay.np,
+               "/fragment@0/__overlay__/lvds");
+       lvds_endpoints[0] = rcar_du_of_find_node_by_path(overlay.np,
+               "/fragment@0/__overlay__/lvds/ports/port@0/endpoint");
+       lvds_endpoints[1] = rcar_du_of_find_node_by_path(overlay.np,
+               "/fragment@0/__overlay__/lvds/ports/port@1/endpoint");
+       du_port = rcar_du_of_find_node_by_path(overlay.np,
+               "/fragment@1/__overlay__/ports/port@0");
+       du_port_fixup = rcar_du_of_find_node_by_path(overlay.np,
+               "/__local_fixups__/fragment@1/__overlay__/ports/port@0");
+       if (!lvds || !lvds_endpoints[0] || !lvds_endpoints[1] ||
+           !du_port || !du_port_fixup)
+               goto out_put_nodes;
+
+       lvds->full_name = kstrdup(name, GFP_KERNEL);
+
+       sprintf(name, "port@%u", port_id);
+       du_port->full_name = kstrdup(name, GFP_KERNEL);
+       du_port_fixup->full_name = kstrdup(name, GFP_KERNEL);
+
+       if (!lvds->full_name || !du_port->full_name ||
+           !du_port_fixup->full_name)
+               goto out_free_names;
+
+       /* Patch the target paths in all fragments. */
+       for_each_child_of_node(overlay.np, fragment) {
+               if (strncmp("fragment@", of_node_full_name(fragment), 9))
+                       continue;
+
+               ret = rcar_du_of_update_target_path(du, remote, fragment);
+               if (ret < 0) {
+                       of_node_put(fragment);
+                       goto out_free_properties;
+               }
+       }
+
+       /*
+        * Create a compatible string for the LVDS node using the SoC model
+        * from the DU node.
+        */
+       ret = of_property_read_string(du, "compatible", &compatible);
+       if (ret < 0)
+               goto out_free_properties;
+
+       soc_suffix = strchr(compatible, '-');
+       if (!soc_suffix || strlen(soc_suffix) > 10)
+               goto out_free_properties;
+
+       psize = sprintf(name, "renesas,lvds%s", soc_suffix) + 1;
+       ret = rcar_du_of_add_property(lvds, "compatible", name, psize);
+       if (ret < 0)
+               goto out_free_properties;
+
+       /* Copy the LVDS reg and clocks properties from the DU node. */
+       psize = (of_n_addr_cells(du) + of_n_size_cells(du)) * 4;
+       ret = rcar_du_of_add_property(lvds, "reg", reg, psize);
+       if (ret < 0)
+               goto out_free_properties;
+
+       if (clkspec->args_count >= ARRAY_SIZE(value) - 1)
+               goto out_free_properties;
+
+       value[0] = cpu_to_be32(clkspec->np->phandle);
+       for (i = 0; i < clkspec->args_count; ++i)
+               value[i + 1] = cpu_to_be32(clkspec->args[i]);
+
+       psize = (clkspec->args_count + 1) * 4;
+       ret = rcar_du_of_add_property(lvds, "clocks", value, psize);
+       if (ret < 0)
+               goto out_free_properties;
+
+       /*
+        * Insert the node in the OF graph: patch the LVDS ports remote-endpoint
+        * properties to point to the endpoints of the sibling nodes in the
+        * graph.
+        */
+       prop = of_find_property(lvds_endpoints[0], "remote-endpoint", NULL);
+       if (!prop)
+               goto out_free_properties;
+
+       *(__be32 *)prop->value = cpu_to_be32(local->phandle);
+
+       prop = of_find_property(lvds_endpoints[1], "remote-endpoint", NULL);
+       if (!prop)
+               goto out_free_properties;
+
+       *(__be32 *)prop->value = cpu_to_be32(remote->phandle);
+
+       /* Apply the overlay, this will resolve phandles. */
+       ovcs_id = 0;
+       ret = of_overlay_apply(overlay.np, &ovcs_id);
+
+       /* We're done, free all allocated memory. */
+out_free_properties:
+       rcar_du_of_free_properties(lvds);
+       rcar_du_of_free_properties(du_port);
+       rcar_du_of_free_properties(du_port_fixup);
+out_free_names:
+       kfree(lvds->full_name);
+       kfree(du_port->full_name);
+       kfree(du_port_fixup->full_name);
+out_put_nodes:
+       of_node_put(lvds);
+       of_node_put(lvds_endpoints[0]);
+       of_node_put(lvds_endpoints[1]);
+       of_node_put(du_port);
+       of_node_put(du_port_fixup);
+
+       rcar_du_of_free_overlay(&overlay);
+}
+
+static void __init rcar_du_of_lvds_patch(const struct of_device_id *of_ids)
+{
+       const struct rcar_du_device_info *info;
+       const struct of_device_id *match;
+       struct device_node *du;
+       unsigned int i;
+       int ret;
+
+       /* Get the DU node and exit if not present or disabled. */
+       du = of_find_matching_node_and_match(NULL, of_ids, &match);
+       if (!du || !of_device_is_available(du))
+               goto done;
+
+       info = match->data;
+
+       /* Patch every LVDS encoder. */
+       for (i = 0; i < info->num_lvds; ++i) {
+               struct of_phandle_args clkspec;
+               struct device_node *local, *remote;
+               struct resource res;
+               unsigned int port_id;
+               const __be32 *reg;
+               char name[7];
+               int index;
+
+               /*
+                * Retrieve the register specifier, the clock specifier and the
+                * local and remote endpoints of the LVDS link.
+                */
+               sprintf(name, "lvds.%u", i);
+               index = of_property_match_string(du, "reg-names", name);
+               if (index < 0)
+                       continue;
+
+               reg = of_get_address(du, index, NULL, NULL);
+               if (!reg)
+                       continue;
+
+               ret = of_address_to_resource(du, index, &res);
+               if (ret < 0)
+                       continue;
+
+               index = of_property_match_string(du, "clock-names", name);
+               if (index < 0)
+                       continue;
+
+               ret = of_parse_phandle_with_args(du, "clocks", "#clock-cells",
+                                                index, &clkspec);
+               if (ret < 0)
+                       continue;
+
+               port_id = info->routes[RCAR_DU_OUTPUT_LVDS0 + i].port;
+
+               local = of_graph_get_endpoint_by_regs(du, port_id, 0);
+               if (!local) {
+                       of_node_put(clkspec.np);
+                       continue;
+               }
+
+               remote = of_graph_get_remote_endpoint(local);
+               if (!remote) {
+                       of_node_put(local);
+                       of_node_put(clkspec.np);
+                       continue;
+               }
+
+               /* Patch the LVDS encoder. */
+               rcar_du_of_lvds_patch_one(du, port_id, &res, reg, &clkspec,
+                                         local, remote);
+
+               of_node_put(clkspec.np);
+               of_node_put(remote);
+               of_node_put(local);
+       }
+
+done:
+       of_node_put(du);
+}
+
+void __init rcar_du_of_init(const struct of_device_id *of_ids)
+{
+       rcar_du_of_lvds_patch(of_ids);
+}
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_of.h 
b/drivers/gpu/drm/rcar-du/rcar_du_of.h
new file mode 100644
index 000000000000..d96bb80df4c2
--- /dev/null
+++ b/drivers/gpu/drm/rcar-du/rcar_du_of.h
@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * rcar_du_of.h - Legacy DT bindings compatibility
+ *
+ * Copyright (C) 2018 Laurent Pinchart <laurent.pinch...@ideasonboard.com>
+ */
+#ifndef __RCAR_DU_OF_H__
+#define __RCAR_DU_OF_H__
+
+#include <linux/init.h>
+
+struct of_device_id;
+
+void __init rcar_du_of_init(const struct of_device_id *of_ids);
+
+#endif /* __RCAR_DU_OF_H__ */
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_of_lvds.dts 
b/drivers/gpu/drm/rcar-du/rcar_du_of_lvds.dts
new file mode 100644
index 000000000000..89ababf15768
--- /dev/null
+++ b/drivers/gpu/drm/rcar-du/rcar_du_of_lvds.dts
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * rcar_du_of_lvds.dts - Legacy LVDS DT bindings conversion
+ *
+ * Copyright (C) 2018 Laurent Pinchart <laurent.pinch...@ideasonboard.com>
+ *
+ * Based on work from Jyri Sarha <jsa...@ti.com>
+ * Copyright (C) 2015 Texas Instruments
+ */
+
+/*
+ * The target-paths, lvds node name, DU port number and LVDS remote endpoints
+ * will be patched dynamically at runtime.
+ */
+
+/dts-v1/;
+/ {
+       fragment@0 {
+               target-path = "soc";
+               __overlay__ {
+                       lvds {
+                               ports {
+                                       #address-cells = <1>;
+                                       #size-cells = <0>;
+
+                                       port@0 {
+                                               reg = <0>;
+                                               lvds_input: endpoint {
+                                                       remote-endpoint = <0>;
+                                               };
+                                       };
+
+                                       port@1 {
+                                               reg = <1>;
+                                               lvds_output: endpoint {
+                                                       remote-endpoint = <0>;
+                                               };
+                                       };
+                               };
+                       };
+               };
+       };
+
+       fragment@1 {
+               target-path = "du";
+               __overlay__ {
+                       ports {
+                               port@0 {
+                                       endpoint {
+                                               remote-endpoint = <&lvds_input>;
+                                       };
+                               };
+                       };
+               };
+       };
+
+       fragment@2 {
+               target-path = "lvds-sink";
+               __overlay__ {
+                       remote-endpoint = <&lvds_output>;
+               };
+       };
+
+       __local_fixups__ {
+               fragment@1 {
+                       __overlay__ {
+                               ports {
+                                       port@0 {
+                                               endpoint {
+                                                       remote-endpoint = <0>;
+                                               };
+                                       };
+                               };
+                       };
+               };
+               fragment@2 {
+                       __overlay__ {
+                               remote-endpoint = <0>;
+                       };
+               };
+       };
+};
-- 
Regards,

Laurent Pinchart

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