From: Marek Vasut <[email protected]>

The Renesas DSC Display Stream Compression is a bridge embedded in the
Renesas R-Car V4H SoC. The bridge performs VESA DSC encoding of up to
8k or 400 Mpixel/s . Add rudimentary driver, which currently acts as a
pass-through bridge and allows DSI1 to be operational on R-Car V4H.

Signed-off-by: Marek Vasut <[email protected]>
[tomi.valkeinen: use bridge->next_bridge, minor changes]
Signed-off-by: Tomi Valkeinen <[email protected]>
---
 drivers/gpu/drm/renesas/rcar-du/Kconfig    |  13 +++
 drivers/gpu/drm/renesas/rcar-du/Makefile   |   1 +
 drivers/gpu/drm/renesas/rcar-du/rcar_dsc.c | 163 +++++++++++++++++++++++++++++
 3 files changed, 177 insertions(+)

diff --git a/drivers/gpu/drm/renesas/rcar-du/Kconfig 
b/drivers/gpu/drm/renesas/rcar-du/Kconfig
index 840305fdeb49..a51f996d3537 100644
--- a/drivers/gpu/drm/renesas/rcar-du/Kconfig
+++ b/drivers/gpu/drm/renesas/rcar-du/Kconfig
@@ -33,6 +33,19 @@ config DRM_RCAR_DW_HDMI
        help
          Enable support for R-Car Gen3 or RZ/G2 internal HDMI encoder.
 
+config DRM_RCAR_USE_DSC
+       bool "R-Car DU DSC Encoder Support"
+       depends on DRM_BRIDGE && OF
+       depends on DRM_RCAR_DU || COMPILE_TEST
+       default DRM_RCAR_DU
+       help
+         Enable support for the R-Car Display Unit embedded DSC encoder.
+
+config DRM_RCAR_DSC
+       def_tristate DRM_RCAR_DU
+       depends on DRM_RCAR_USE_DSC
+       select RESET_CONTROLLER
+
 config DRM_RCAR_USE_LVDS
        bool "R-Car DU LVDS Encoder Support"
        depends on DRM_BRIDGE && OF
diff --git a/drivers/gpu/drm/renesas/rcar-du/Makefile 
b/drivers/gpu/drm/renesas/rcar-du/Makefile
index 6f132325c8b7..cc27b2265d94 100644
--- a/drivers/gpu/drm/renesas/rcar-du/Makefile
+++ b/drivers/gpu/drm/renesas/rcar-du/Makefile
@@ -12,5 +12,6 @@ rcar-du-drm-$(CONFIG_DRM_RCAR_WRITEBACK) += 
rcar_du_writeback.o
 obj-$(CONFIG_DRM_RCAR_CMM)             += rcar_cmm.o
 obj-$(CONFIG_DRM_RCAR_DU)              += rcar-du-drm.o
 obj-$(CONFIG_DRM_RCAR_DW_HDMI)         += rcar_dw_hdmi.o
+obj-$(CONFIG_DRM_RCAR_DSC)             += rcar_dsc.o
 obj-$(CONFIG_DRM_RCAR_LVDS)            += rcar_lvds.o
 obj-$(CONFIG_DRM_RCAR_MIPI_DSI)                += rcar_mipi_dsi.o
diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_dsc.c 
b/drivers/gpu/drm/renesas/rcar-du/rcar_dsc.c
new file mode 100644
index 000000000000..2ab5a4bb099c
--- /dev/null
+++ b/drivers/gpu/drm/renesas/rcar-du/rcar_dsc.c
@@ -0,0 +1,163 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * R-Car DSC Encoder
+ *
+ * Copyright (C) 2025 Marek Vasut <[email protected]>
+ * Copyright (C) 2025 Renesas Electronics Corporation
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_graph.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_bridge.h>
+#include <drm/drm_of.h>
+
+struct rcar_dsc {
+       struct drm_bridge bridge;
+
+       struct device *dev;
+       void __iomem *mmio;
+       struct clk *clk;
+       struct reset_control *rst;
+};
+
+static inline struct rcar_dsc *bridge_to_rcar_dsc(struct drm_bridge *bridge)
+{
+       return container_of(bridge, struct rcar_dsc, bridge);
+}
+
+/* 
-----------------------------------------------------------------------------
+ * Bridge
+ */
+
+static int rcar_dsc_attach(struct drm_bridge *bridge,
+                          struct drm_encoder *encoder,
+                          enum drm_bridge_attach_flags flags)
+{
+       struct rcar_dsc *dsc = bridge_to_rcar_dsc(bridge);
+
+       if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR))
+               return -EINVAL;
+
+       return drm_bridge_attach(encoder, dsc->bridge.next_bridge, bridge,
+                                DRM_BRIDGE_ATTACH_NO_CONNECTOR);
+}
+
+static void rcar_dsc_atomic_enable(struct drm_bridge *bridge,
+                                  struct drm_atomic_state *state)
+{
+       struct rcar_dsc *dsc = bridge_to_rcar_dsc(bridge);
+
+       WARN_ON(clk_prepare_enable(dsc->clk));
+       WARN_ON(reset_control_deassert(dsc->rst));
+}
+
+static void rcar_dsc_atomic_disable(struct drm_bridge *bridge,
+                                   struct drm_atomic_state *state)
+{
+       struct rcar_dsc *dsc = bridge_to_rcar_dsc(bridge);
+
+       reset_control_assert(dsc->rst);
+       clk_disable_unprepare(dsc->clk);
+}
+
+static enum drm_mode_status
+rcar_dsc_bridge_mode_valid(struct drm_bridge *bridge,
+                          const struct drm_display_info *info,
+                          const struct drm_display_mode *mode)
+{
+       if (mode->hdisplay < 320 || mode->hdisplay > 8190)
+               return MODE_BAD_HVALUE;
+
+       if (mode->vdisplay < 160 || mode->vdisplay > 8190)
+               return MODE_BAD_VVALUE;
+
+       if (mode->clock > 400000) /* Really 400 Mpixel/s */
+               return MODE_CLOCK_HIGH;
+
+       return MODE_OK;
+}
+
+static const struct drm_bridge_funcs rcar_dsc_bridge_ops = {
+       .attach = rcar_dsc_attach,
+       .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
+       .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
+       .atomic_reset = drm_atomic_helper_bridge_reset,
+       .atomic_enable = rcar_dsc_atomic_enable,
+       .atomic_disable = rcar_dsc_atomic_disable,
+       .mode_valid = rcar_dsc_bridge_mode_valid,
+};
+
+/* 
-----------------------------------------------------------------------------
+ * Probe & Remove
+ */
+
+static int rcar_dsc_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct device_node *remote;
+       struct rcar_dsc *dsc;
+
+       dsc = devm_drm_bridge_alloc(dev, struct rcar_dsc, bridge,
+                                   &rcar_dsc_bridge_ops);
+       if (IS_ERR(dsc))
+               return PTR_ERR(dsc);
+
+       platform_set_drvdata(pdev, dsc);
+
+       dsc->dev = &pdev->dev;
+
+       /* Acquire resources. */
+       dsc->mmio = devm_platform_ioremap_resource(pdev, 0);
+       if (IS_ERR(dsc->mmio))
+               return PTR_ERR(dsc->mmio);
+
+       dsc->clk = devm_clk_get(dev, NULL);
+       if (IS_ERR(dsc->clk))
+               return dev_err_probe(dev, PTR_ERR(dsc->clk),
+                                    "Failed to get CPG clock\n");
+
+       dsc->rst = devm_reset_control_get(dev, NULL);
+       if (IS_ERR(dsc->rst))
+               return dev_err_probe(dev, PTR_ERR(dsc->rst),
+                                    "Failed to get CPG reset\n");
+
+       remote = of_graph_get_remote_node(dev->of_node, 1, 0);
+       if (!remote)
+               return -EINVAL;
+
+       dsc->bridge.next_bridge = of_drm_find_and_get_bridge(remote);
+       of_node_put(remote);
+       if (!dsc->bridge.next_bridge)
+               return -EPROBE_DEFER;
+
+       dsc->bridge.of_node = dev->of_node;
+
+       return devm_drm_bridge_add(dev, &dsc->bridge);
+}
+
+static const struct of_device_id rcar_dsc_of_table[] = {
+       { .compatible = "renesas,r8a779g0-dsc" },
+       {}
+};
+
+MODULE_DEVICE_TABLE(of, rcar_dsc_of_table);
+
+static struct platform_driver rcar_dsc_platform_driver = {
+       .probe          = rcar_dsc_probe,
+       .driver         = {
+               .name   = "rcar-dsc",
+               .of_match_table = rcar_dsc_of_table,
+       },
+};
+
+module_platform_driver(rcar_dsc_platform_driver);
+
+MODULE_DESCRIPTION("Renesas R-Car DSC Encoder Driver");
+MODULE_LICENSE("GPL");

-- 
2.43.0

Reply via email to