drm/meson: add DSI encoder

This adds an encoder bridge designed to drive a MIPI-DSI display
by using the ENCL encoder through the internal MIPI DSI transceiver
connected to the output of the ENCL pixel encoder.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

drivers/gpu/drm/meson/Makefile

@@ -2,7 +2,7 @@
 meson-drm-y := meson_drv.o meson_plane.o meson_crtc.o meson_encoder_cvbs.o
 meson-drm-y += meson_viu.o meson_vpp.o meson_venc.o meson_vclk.o meson_overlay.o
 meson-drm-y += meson_rdma.o meson_osd_afbcd.o
-meson-drm-y += meson_encoder_hdmi.o
+meson-drm-y += meson_encoder_hdmi.o meson_encoder_dsi.o
 
 obj-$(CONFIG_DRM_MESON) += meson-drm.o
 obj-$(CONFIG_DRM_MESON_DW_HDMI) += meson_dw_hdmi.o

drivers/gpu/drm/meson/meson_drv.c

@@ -33,6 +33,7 @@
 #include "meson_registers.h"
 #include "meson_encoder_cvbs.h"
 #include "meson_encoder_hdmi.h"
+#include "meson_encoder_dsi.h"
 #include "meson_viu.h"
 #include "meson_vpp.h"
 #include "meson_rdma.h"
@@ -323,6 +324,12 @@ static int meson_drv_bind_master(struct device *dev, bool has_components)
 	if (ret)
 		goto exit_afbcd;
 
+	if (meson_vpu_is_compatible(priv, VPU_COMPATIBLE_G12A)) {
+		ret = meson_encoder_dsi_init(priv);
+		if (ret)
+			goto free_drm;
+	}
+
 	ret = meson_plane_create(priv);
 	if (ret)
 		goto exit_afbcd;

drivers/gpu/drm/meson/meson_encoder_dsi.c

@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2016 BayLibre, SAS
+ * Author: Neil Armstrong <narmstrong@baylibre.com>
+ * Copyright (C) 2015 Amlogic, Inc. All rights reserved.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of_graph.h>
+
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_simple_kms_helper.h>
+#include <drm/drm_bridge.h>
+#include <drm/drm_bridge_connector.h>
+#include <drm/drm_device.h>
+#include <drm/drm_probe_helper.h>
+
+#include "meson_drv.h"
+#include "meson_encoder_dsi.h"
+#include "meson_registers.h"
+#include "meson_venc.h"
+#include "meson_vclk.h"
+
+struct meson_encoder_dsi {
+	struct drm_encoder encoder;
+	struct drm_bridge bridge;
+	struct drm_bridge *next_bridge;
+	struct meson_drm *priv;
+};
+
+#define bridge_to_meson_encoder_dsi(x) \
+	container_of(x, struct meson_encoder_dsi, bridge)
+
+static int meson_encoder_dsi_attach(struct drm_bridge *bridge,
+				    enum drm_bridge_attach_flags flags)
+{
+	struct meson_encoder_dsi *encoder_dsi = bridge_to_meson_encoder_dsi(bridge);
+
+	return drm_bridge_attach(bridge->encoder, encoder_dsi->next_bridge,
+				 &encoder_dsi->bridge, flags);
+}
+
+static void meson_encoder_dsi_mode_set(struct drm_bridge *bridge,
+				       const struct drm_display_mode *mode,
+				       const struct drm_display_mode *adjusted_mode)
+{
+	struct meson_encoder_dsi *encoder_dsi = bridge_to_meson_encoder_dsi(bridge);
+	struct meson_drm *priv = encoder_dsi->priv;
+
+	meson_vclk_setup(priv, MESON_VCLK_TARGET_DSI, mode->clock, 0, 0, 0, false);
+
+	meson_venc_mipi_dsi_mode_set(priv, mode);
+	meson_encl_load_gamma(priv);
+
+	writel_relaxed(0, priv->io_base + _REG(ENCL_VIDEO_EN));
+
+	writel_bits_relaxed(ENCL_VIDEO_MODE_ADV_VFIFO_EN, ENCL_VIDEO_MODE_ADV_VFIFO_EN,
+			    priv->io_base + _REG(ENCL_VIDEO_MODE_ADV));
+	writel_relaxed(0, priv->io_base + _REG(ENCL_TST_EN));
+}
+
+static void meson_encoder_dsi_atomic_enable(struct drm_bridge *bridge,
+					    struct drm_bridge_state *bridge_state)
+{
+	struct meson_encoder_dsi *encoder_dsi = bridge_to_meson_encoder_dsi(bridge);
+	struct meson_drm *priv = encoder_dsi->priv;
+
+	writel_bits_relaxed(BIT(0), 0, priv->io_base + _REG(VPP_WRAP_OSD1_MATRIX_EN_CTRL));
+
+	writel_relaxed(1, priv->io_base + _REG(ENCL_VIDEO_EN));
+}
+
+static void meson_encoder_dsi_atomic_disable(struct drm_bridge *bridge,
+					     struct drm_bridge_state *bridge_state)
+{
+	struct meson_encoder_dsi *meson_encoder_dsi =
+					bridge_to_meson_encoder_dsi(bridge);
+	struct meson_drm *priv = meson_encoder_dsi->priv;
+
+	writel_relaxed(0, priv->io_base + _REG(ENCL_VIDEO_EN));
+
+	writel_bits_relaxed(BIT(0), BIT(0), priv->io_base + _REG(VPP_WRAP_OSD1_MATRIX_EN_CTRL));
+}
+
+static const struct drm_bridge_funcs meson_encoder_dsi_bridge_funcs = {
+	.attach	= meson_encoder_dsi_attach,
+	/*
+	 * TOFIX: remove when dw-mipi-dsi moves out of mode_set
+	 * We should get rid of mode_set, but until dw-mipi-dsi uses it
+	 * we need to setup the pixel clock before the following
+	 * bridge tries to setup the HW.
+	 */
+	.mode_set = meson_encoder_dsi_mode_set,
+	.atomic_enable = meson_encoder_dsi_atomic_enable,
+	.atomic_disable	= meson_encoder_dsi_atomic_disable,
+	.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,
+};
+
+int meson_encoder_dsi_init(struct meson_drm *priv)
+{
+	struct meson_encoder_dsi *meson_encoder_dsi;
+	struct device_node *remote;
+	int ret;
+
+	meson_encoder_dsi = devm_kzalloc(priv->dev, sizeof(*meson_encoder_dsi), GFP_KERNEL);
+	if (!meson_encoder_dsi)
+		return -ENOMEM;
+
+	/* DSI Transceiver Bridge */
+	remote = of_graph_get_remote_node(priv->dev->of_node, 2, 0);
+	if (!remote) {
+		dev_err(priv->dev, "DSI transceiver device is disabled");
+		return 0;
+	}
+
+	meson_encoder_dsi->next_bridge = of_drm_find_bridge(remote);
+	if (!meson_encoder_dsi->next_bridge) {
+		dev_dbg(priv->dev, "Failed to find DSI transceiver bridge: %d\n", ret);
+		return -EPROBE_DEFER;
+	}
+
+	/* DSI Encoder Bridge */
+	meson_encoder_dsi->bridge.funcs = &meson_encoder_dsi_bridge_funcs;
+	meson_encoder_dsi->bridge.of_node = priv->dev->of_node;
+	meson_encoder_dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
+
+	drm_bridge_add(&meson_encoder_dsi->bridge);
+
+	meson_encoder_dsi->priv = priv;
+
+	/* Encoder */
+	ret = drm_simple_encoder_init(priv->drm, &meson_encoder_dsi->encoder,
+				      DRM_MODE_ENCODER_DSI);
+	if (ret) {
+		dev_err(priv->dev, "Failed to init DSI encoder: %d\n", ret);
+		return ret;
+	}
+
+	meson_encoder_dsi->encoder.possible_crtcs = BIT(0);
+
+	/* Attach DSI Encoder Bridge to Encoder */
+	ret = drm_bridge_attach(&meson_encoder_dsi->encoder, &meson_encoder_dsi->bridge, NULL, 0);
+	if (ret) {
+		dev_err(priv->dev, "Failed to attach bridge: %d\n", ret);
+		return ret;
+	}
+
+	/*
+	 * We should have now in place:
+	 * encoder->[dsi encoder bridge]->[dw-mipi-dsi bridge]->[panel bridge]->[panel]
+	 */
+
+	dev_dbg(priv->dev, "DSI encoder initialized\n");
+
+	return 0;
+}

drivers/gpu/drm/meson/meson_encoder_dsi.h

@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2021 BayLibre, SAS
+ * Author: Neil Armstrong <narmstrong@baylibre.com>
+ */
+
+#ifndef __MESON_ENCODER_DSI_H
+#define __MESON_ENCODER_DSI_H
+
+int meson_encoder_dsi_init(struct meson_drm *priv);
+
+#endif /* __MESON_ENCODER_DSI_H */