drm: rcar-du: Convert LVDS encoder code to bridge driver

The LVDS encoders used to be described in DT as part of the DU. They now
have their own DT node, linked to the DU using the OF graph bindings.
This allows moving internal LVDS encoder support to a separate driver
modelled as a DRM bridge. Backward compatibility is retained as legacy
DT is patched live to move to the new bindings.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

1 files changed, 524 insertions, 0 deletions

diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
new file mode 100644
index 000000000000..1247e26a0559
--- /dev/null
+++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
@@ -0,0 +1,524 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * rcar_lvds.c  --  R-Car LVDS Encoder
+ *
+ * Copyright (C) 2013-2018 Renesas Electronics Corporation
+ *
+ * Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.com)
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_graph.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include <drm/drm_atomic.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_bridge.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_panel.h>
+
+#include "rcar_lvds_regs.h"
+
+/* Keep in sync with the LVDCR0.LVMD hardware register values. */
+enum rcar_lvds_mode {
+	RCAR_LVDS_MODE_JEIDA = 0,
+	RCAR_LVDS_MODE_MIRROR = 1,
+	RCAR_LVDS_MODE_VESA = 4,
+};
+
+#define RCAR_LVDS_QUIRK_LANES	(1 << 0)	/* LVDS lanes 1 and 3 inverted */
+
+struct rcar_lvds_device_info {
+	unsigned int gen;
+	unsigned int quirks;
+};
+
+struct rcar_lvds {
+	struct device *dev;
+	const struct rcar_lvds_device_info *info;
+
+	struct drm_bridge bridge;
+
+	struct drm_bridge *next_bridge;
+	struct drm_connector connector;
+	struct drm_panel *panel;
+
+	void __iomem *mmio;
+	struct clk *clock;
+	bool enabled;
+
+	struct drm_display_mode display_mode;
+	enum rcar_lvds_mode mode;
+};
+
+#define bridge_to_rcar_lvds(bridge) \
+	container_of(bridge, struct rcar_lvds, bridge)
+
+#define connector_to_rcar_lvds(connector) \
+	container_of(connector, struct rcar_lvds, connector)
+
+static void rcar_lvds_write(struct rcar_lvds *lvds, u32 reg, u32 data)
+{
+	iowrite32(data, lvds->mmio + reg);
+}
+
+/* -----------------------------------------------------------------------------
+ * Connector & Panel
+ */
+
+static int rcar_lvds_connector_get_modes(struct drm_connector *connector)
+{
+	struct rcar_lvds *lvds = connector_to_rcar_lvds(connector);
+
+	return drm_panel_get_modes(lvds->panel);
+}
+
+static int rcar_lvds_connector_atomic_check(struct drm_connector *connector,
+					    struct drm_connector_state *state)
+{
+	struct rcar_lvds *lvds = connector_to_rcar_lvds(connector);
+	const struct drm_display_mode *panel_mode;
+	struct drm_crtc_state *crtc_state;
+
+	if (list_empty(&connector->modes)) {
+		dev_dbg(lvds->dev, "connector: empty modes list\n");
+		return -EINVAL;
+	}
+
+	panel_mode = list_first_entry(&connector->modes,
+				      struct drm_display_mode, head);
+
+	/* We're not allowed to modify the resolution. */
+	crtc_state = drm_atomic_get_crtc_state(state->state, state->crtc);
+	if (IS_ERR(crtc_state))
+		return PTR_ERR(crtc_state);
+
+	if (crtc_state->mode.hdisplay != panel_mode->hdisplay ||
+	    crtc_state->mode.vdisplay != panel_mode->vdisplay)
+		return -EINVAL;
+
+	/* The flat panel mode is fixed, just copy it to the adjusted mode. */
+	drm_mode_copy(&crtc_state->adjusted_mode, panel_mode);
+
+	return 0;
+}
+
+static const struct drm_connector_helper_funcs rcar_lvds_conn_helper_funcs = {
+	.get_modes = rcar_lvds_connector_get_modes,
+	.atomic_check = rcar_lvds_connector_atomic_check,
+};
+
+static const struct drm_connector_funcs rcar_lvds_conn_funcs = {
+	.reset = drm_atomic_helper_connector_reset,
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.destroy = drm_connector_cleanup,
+	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+/* -----------------------------------------------------------------------------
+ * Bridge
+ */
+
+static u32 rcar_lvds_lvdpllcr_gen2(unsigned int freq)
+{
+	if (freq < 39000)
+		return LVDPLLCR_CEEN | LVDPLLCR_COSEL | LVDPLLCR_PLLDLYCNT_38M;
+	else if (freq < 61000)
+		return LVDPLLCR_CEEN | LVDPLLCR_COSEL | LVDPLLCR_PLLDLYCNT_60M;
+	else if (freq < 121000)
+		return LVDPLLCR_CEEN | LVDPLLCR_COSEL | LVDPLLCR_PLLDLYCNT_121M;
+	else
+		return LVDPLLCR_PLLDLYCNT_150M;
+}
+
+static u32 rcar_lvds_lvdpllcr_gen3(unsigned int freq)
+{
+	if (freq < 42000)
+		return LVDPLLCR_PLLDIVCNT_42M;
+	else if (freq < 85000)
+		return LVDPLLCR_PLLDIVCNT_85M;
+	else if (freq < 128000)
+		return LVDPLLCR_PLLDIVCNT_128M;
+	else
+		return LVDPLLCR_PLLDIVCNT_148M;
+}
+
+static void rcar_lvds_enable(struct drm_bridge *bridge)
+{
+	struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
+	const struct drm_display_mode *mode = &lvds->display_mode;
+	/*
+	 * FIXME: We should really retrieve the CRTC through the state, but how
+	 * do we get a state pointer?
+	 */
+	struct drm_crtc *crtc = lvds->bridge.encoder->crtc;
+	u32 lvdpllcr;
+	u32 lvdhcr;
+	u32 lvdcr0;
+	int ret;
+
+	WARN_ON(lvds->enabled);
+
+	ret = clk_prepare_enable(lvds->clock);
+	if (ret < 0)
+		return;
+
+	/*
+	 * Hardcode the channels and control signals routing for now.
+	 *
+	 * HSYNC -> CTRL0
+	 * VSYNC -> CTRL1
+	 * DISP  -> CTRL2
+	 * 0     -> CTRL3
+	 */
+	rcar_lvds_write(lvds, LVDCTRCR, LVDCTRCR_CTR3SEL_ZERO |
+			LVDCTRCR_CTR2SEL_DISP | LVDCTRCR_CTR1SEL_VSYNC |
+			LVDCTRCR_CTR0SEL_HSYNC);
+
+	if (lvds->info->quirks & RCAR_LVDS_QUIRK_LANES)
+		lvdhcr = LVDCHCR_CHSEL_CH(0, 0) | LVDCHCR_CHSEL_CH(1, 3)
+		       | LVDCHCR_CHSEL_CH(2, 2) | LVDCHCR_CHSEL_CH(3, 1);
+	else
+		lvdhcr = LVDCHCR_CHSEL_CH(0, 0) | LVDCHCR_CHSEL_CH(1, 1)
+		       | LVDCHCR_CHSEL_CH(2, 2) | LVDCHCR_CHSEL_CH(3, 3);
+
+	rcar_lvds_write(lvds, LVDCHCR, lvdhcr);
+
+	/* PLL clock configuration. */
+	if (lvds->info->gen < 3)
+		lvdpllcr = rcar_lvds_lvdpllcr_gen2(mode->clock);
+	else
+		lvdpllcr = rcar_lvds_lvdpllcr_gen3(mode->clock);
+	rcar_lvds_write(lvds, LVDPLLCR, lvdpllcr);
+
+	/* Set the LVDS mode and select the input. */
+	lvdcr0 = lvds->mode << LVDCR0_LVMD_SHIFT;
+	if (drm_crtc_index(crtc) == 2)
+		lvdcr0 |= LVDCR0_DUSEL;
+	rcar_lvds_write(lvds, LVDCR0, lvdcr0);
+
+	/* Turn all the channels on. */
+	rcar_lvds_write(lvds, LVDCR1,
+			LVDCR1_CHSTBY(3) | LVDCR1_CHSTBY(2) |
+			LVDCR1_CHSTBY(1) | LVDCR1_CHSTBY(0) | LVDCR1_CLKSTBY);
+
+	if (lvds->info->gen < 3) {
+		/* Enable LVDS operation and turn the bias circuitry on. */
+		lvdcr0 |= LVDCR0_BEN | LVDCR0_LVEN;
+		rcar_lvds_write(lvds, LVDCR0, lvdcr0);
+	}
+
+	/* Turn the PLL on. */
+	lvdcr0 |= LVDCR0_PLLON;
+	rcar_lvds_write(lvds, LVDCR0, lvdcr0);
+
+	if (lvds->info->gen > 2) {
+		/* Set LVDS normal mode. */
+		lvdcr0 |= LVDCR0_PWD;
+		rcar_lvds_write(lvds, LVDCR0, lvdcr0);
+	}
+
+	/* Wait for the startup delay. */
+	usleep_range(100, 150);
+
+	/* Turn the output on. */
+	lvdcr0 |= LVDCR0_LVRES;
+	rcar_lvds_write(lvds, LVDCR0, lvdcr0);
+
+	if (lvds->panel) {
+		drm_panel_prepare(lvds->panel);
+		drm_panel_enable(lvds->panel);
+	}
+
+	lvds->enabled = true;
+}
+
+static void rcar_lvds_disable(struct drm_bridge *bridge)
+{
+	struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
+
+	WARN_ON(!lvds->enabled);
+
+	if (lvds->panel) {
+		drm_panel_disable(lvds->panel);
+		drm_panel_unprepare(lvds->panel);
+	}
+
+	rcar_lvds_write(lvds, LVDCR0, 0);
+	rcar_lvds_write(lvds, LVDCR1, 0);
+
+	clk_disable_unprepare(lvds->clock);
+
+	lvds->enabled = false;
+}
+
+static bool rcar_lvds_mode_fixup(struct drm_bridge *bridge,
+				 const struct drm_display_mode *mode,
+				 struct drm_display_mode *adjusted_mode)
+{
+	/*
+	 * The internal LVDS encoder has a restricted clock frequency operating
+	 * range (31MHz to 148.5MHz). Clamp the clock accordingly.
+	 */
+	adjusted_mode->clock = clamp(adjusted_mode->clock, 31000, 148500);
+
+	return true;
+}
+
+static void rcar_lvds_get_lvds_mode(struct rcar_lvds *lvds)
+{
+	struct drm_display_info *info = &lvds->connector.display_info;
+	enum rcar_lvds_mode mode;
+
+	/*
+	 * There is no API yet to retrieve LVDS mode from a bridge, only panels
+	 * are supported.
+	 */
+	if (!lvds->panel)
+		return;
+
+	if (!info->num_bus_formats || !info->bus_formats) {
+		dev_err(lvds->dev, "no LVDS bus format reported\n");
+		return;
+	}
+
+	switch (info->bus_formats[0]) {
+	case MEDIA_BUS_FMT_RGB666_1X7X3_SPWG:
+	case MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA:
+		mode = RCAR_LVDS_MODE_JEIDA;
+		break;
+	case MEDIA_BUS_FMT_RGB888_1X7X4_SPWG:
+		mode = RCAR_LVDS_MODE_VESA;
+		break;
+	default:
+		dev_err(lvds->dev, "unsupported LVDS bus format 0x%04x\n",
+			info->bus_formats[0]);
+		return;
+	}
+
+	if (info->bus_flags & DRM_BUS_FLAG_DATA_LSB_TO_MSB)
+		mode |= RCAR_LVDS_MODE_MIRROR;
+
+	lvds->mode = mode;
+}
+
+static void rcar_lvds_mode_set(struct drm_bridge *bridge,
+			       struct drm_display_mode *mode,
+			       struct drm_display_mode *adjusted_mode)
+{
+	struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
+
+	WARN_ON(lvds->enabled);
+
+	lvds->display_mode = *adjusted_mode;
+
+	rcar_lvds_get_lvds_mode(lvds);
+}
+
+static int rcar_lvds_attach(struct drm_bridge *bridge)
+{
+	struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
+	struct drm_connector *connector = &lvds->connector;
+	struct drm_encoder *encoder = bridge->encoder;
+	int ret;
+
+	/* If we have a next bridge just attach it. */
+	if (lvds->next_bridge)
+		return drm_bridge_attach(bridge->encoder, lvds->next_bridge,
+					 bridge);
+
+	/* Otherwise we have a panel, create a connector. */
+	ret = drm_connector_init(bridge->dev, connector, &rcar_lvds_conn_funcs,
+				 DRM_MODE_CONNECTOR_LVDS);
+	if (ret < 0)
+		return ret;
+
+	drm_connector_helper_add(connector, &rcar_lvds_conn_helper_funcs);
+
+	ret = drm_mode_connector_attach_encoder(connector, encoder);
+	if (ret < 0)
+		return ret;
+
+	return drm_panel_attach(lvds->panel, connector);
+}
+
+static void rcar_lvds_detach(struct drm_bridge *bridge)
+{
+	struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
+
+	if (lvds->panel)
+		drm_panel_detach(lvds->panel);
+}
+
+static const struct drm_bridge_funcs rcar_lvds_bridge_ops = {
+	.attach = rcar_lvds_attach,
+	.detach = rcar_lvds_detach,
+	.enable = rcar_lvds_enable,
+	.disable = rcar_lvds_disable,
+	.mode_fixup = rcar_lvds_mode_fixup,
+	.mode_set = rcar_lvds_mode_set,
+};
+
+/* -----------------------------------------------------------------------------
+ * Probe & Remove
+ */
+
+static int rcar_lvds_parse_dt(struct rcar_lvds *lvds)
+{
+	struct device_node *local_output = NULL;
+	struct device_node *remote_input = NULL;
+	struct device_node *remote = NULL;
+	struct device_node *node;
+	bool is_bridge = false;
+	int ret = 0;
+
+	local_output = of_graph_get_endpoint_by_regs(lvds->dev->of_node, 1, 0);
+	if (!local_output) {
+		dev_dbg(lvds->dev, "unconnected port@1\n");
+		return -ENODEV;
+	}
+
+	/*
+	 * Locate the connected entity and infer its type from the number of
+	 * endpoints.
+	 */
+	remote = of_graph_get_remote_port_parent(local_output);
+	if (!remote) {
+		dev_dbg(lvds->dev, "unconnected endpoint %pOF\n", local_output);
+		ret = -ENODEV;
+		goto done;
+	}
+
+	if (!of_device_is_available(remote)) {
+		dev_dbg(lvds->dev, "connected entity %pOF is disabled\n",
+			remote);
+		ret = -ENODEV;
+		goto done;
+	}
+
+	remote_input = of_graph_get_remote_endpoint(local_output);
+
+	for_each_endpoint_of_node(remote, node) {
+		if (node != remote_input) {
+			/*
+			 * We've found one endpoint other than the input, this
+			 * must be a bridge.
+			 */
+			is_bridge = true;
+			of_node_put(node);
+			break;
+		}
+	}
+
+	if (is_bridge) {
+		lvds->next_bridge = of_drm_find_bridge(remote);
+		if (!lvds->next_bridge)
+			ret = -EPROBE_DEFER;
+	} else {
+		lvds->panel = of_drm_find_panel(remote);
+		if (!lvds->panel)
+			ret = -EPROBE_DEFER;
+	}
+
+done:
+	of_node_put(local_output);
+	of_node_put(remote_input);
+	of_node_put(remote);
+
+	return ret;
+}
+
+static int rcar_lvds_probe(struct platform_device *pdev)
+{
+	struct rcar_lvds *lvds;
+	struct resource *mem;
+	int ret;
+
+	lvds = devm_kzalloc(&pdev->dev, sizeof(*lvds), GFP_KERNEL);
+	if (lvds == NULL)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, lvds);
+
+	lvds->dev = &pdev->dev;
+	lvds->info = of_device_get_match_data(&pdev->dev);
+	lvds->enabled = false;
+
+	ret = rcar_lvds_parse_dt(lvds);
+	if (ret < 0)
+		return ret;
+
+	lvds->bridge.driver_private = lvds;
+	lvds->bridge.funcs = &rcar_lvds_bridge_ops;
+	lvds->bridge.of_node = pdev->dev.of_node;
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	lvds->mmio = devm_ioremap_resource(&pdev->dev, mem);
+	if (IS_ERR(lvds->mmio))
+		return PTR_ERR(lvds->mmio);
+
+	lvds->clock = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(lvds->clock)) {
+		dev_err(&pdev->dev, "failed to get clock\n");
+		return PTR_ERR(lvds->clock);
+	}
+
+	drm_bridge_add(&lvds->bridge);
+
+	return 0;
+}
+
+static int rcar_lvds_remove(struct platform_device *pdev)
+{
+	struct rcar_lvds *lvds = platform_get_drvdata(pdev);
+
+	drm_bridge_remove(&lvds->bridge);
+
+	return 0;
+}
+
+static const struct rcar_lvds_device_info rcar_lvds_gen2_info = {
+	.gen = 2,
+};
+
+static const struct rcar_lvds_device_info rcar_lvds_r8a7790_info = {
+	.gen = 2,
+	.quirks = RCAR_LVDS_QUIRK_LANES,
+};
+
+static const struct rcar_lvds_device_info rcar_lvds_gen3_info = {
+	.gen = 3,
+};
+
+static const struct of_device_id rcar_lvds_of_table[] = {
+	{ .compatible = "renesas,r8a7743-lvds", .data = &rcar_lvds_gen2_info },
+	{ .compatible = "renesas,r8a7790-lvds", .data = &rcar_lvds_r8a7790_info },
+	{ .compatible = "renesas,r8a7791-lvds", .data = &rcar_lvds_gen2_info },
+	{ .compatible = "renesas,r8a7793-lvds", .data = &rcar_lvds_gen2_info },
+	{ .compatible = "renesas,r8a7795-lvds", .data = &rcar_lvds_gen3_info },
+	{ .compatible = "renesas,r8a7796-lvds", .data = &rcar_lvds_gen3_info },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(of, rcar_lvds_of_table);
+
+static struct platform_driver rcar_lvds_platform_driver = {
+	.probe		= rcar_lvds_probe,
+	.remove		= rcar_lvds_remove,
+	.driver		= {
+		.name	= "rcar-lvds",
+		.of_match_table = rcar_lvds_of_table,
+	},
+};
+
+module_platform_driver(rcar_lvds_platform_driver);
+
+MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
+MODULE_DESCRIPTION("Renesas R-Car LVDS Encoder Driver");
+MODULE_LICENSE("GPL");