Add a simple and transparent LVDS de/encoder driver with a powerdown
gpio and a power supply.
Signed-off-by: Svyatoslav Ryhel <clamo...@gmail.com>
---
drivers/video/bridge/Kconfig | 7 ++
drivers/video/bridge/Makefile | 1 +
drivers/video/bridge/lvds-codec.c | 128 ++++++++++++++++++++++++++++++
3 files changed, 136 insertions(+)
create mode 100644 drivers/video/bridge/lvds-codec.c
diff --git a/drivers/video/bridge/Kconfig b/drivers/video/bridge/Kconfig
index ab917273720..21c5a043e02 100644
--- a/drivers/video/bridge/Kconfig
+++ b/drivers/video/bridge/Kconfig
@@ -59,3 +59,10 @@ config VIDEO_BRIDGE_TOSHIBA_TC358768
help
Toshiba TC358768AXBG/TC358778XBG DSI bridge chip driver.
Found in Asus Transformer Infinity TF700T.
+
+config VIDEO_BRIDGE_LVDS_CODEC
+ bool "Transparent LVDS encoders and decoders support"
+ depends on VIDEO_BRIDGE && PANEL && DM_GPIO
+ help
+ Support for transparent LVDS encoders and decoders that don't
+ require any configuration.
diff --git a/drivers/video/bridge/Makefile b/drivers/video/bridge/Makefile
index 58697e3cbe9..63dc6e62c49 100644
--- a/drivers/video/bridge/Makefile
+++ b/drivers/video/bridge/Makefile
@@ -10,3 +10,4 @@ obj-$(CONFIG_VIDEO_BRIDGE_NXP_PTN3460) += ptn3460.o
obj-$(CONFIG_VIDEO_BRIDGE_ANALOGIX_ANX6345) += anx6345.o
obj-$(CONFIG_VIDEO_BRIDGE_SOLOMON_SSD2825) += ssd2825.o
obj-$(CONFIG_VIDEO_BRIDGE_TOSHIBA_TC358768) += tc358768.o
+obj-$(CONFIG_VIDEO_BRIDGE_LVDS_CODEC) += lvds-codec.o
diff --git a/drivers/video/bridge/lvds-codec.c
b/drivers/video/bridge/lvds-codec.c
new file mode 100644
index 00000000000..6cd8368a39e
--- /dev/null
+++ b/drivers/video/bridge/lvds-codec.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2025 Svyatoslav Ryhel <clamo...@gmail.com>
+ * Loosely based on Linux lvds-codec.c driver
+ */
+
+#include <dm.h>
+#include <dm/ofnode_graph.h>
+#include <log.h>
+#include <panel.h>
+#include <video_bridge.h>
+#include <asm/gpio.h>
+#include <power/regulator.h>
+
+struct lvds_codec_priv {
+ struct udevice *panel;
+ struct display_timing timing;
+
+ struct gpio_desc powerdown_gpio;
+ struct udevice *power;
+};
+
+static int lvds_codec_attach(struct udevice *dev)
+{
+ struct lvds_codec_priv *priv = dev_get_priv(dev);
+
+ regulator_set_enable_if_allowed(priv->power, 1);
+ dm_gpio_set_value(&priv->powerdown_gpio, 0);
+
+ return panel_enable_backlight(priv->panel);
+}
+
+static int lvds_codec_set_panel(struct udevice *dev, int percent)
+{
+ struct lvds_codec_priv *priv = dev_get_priv(dev);
+
+ return panel_set_backlight(priv->panel, percent);
+}
+
+static int lvds_codec_panel_timings(struct udevice *dev,
+ struct display_timing *timing)
+{
+ struct lvds_codec_priv *priv = dev_get_priv(dev);
+
+ memcpy(timing, &priv->timing, sizeof(*timing));
+
+ return 0;
+}
+
+/* Function is purely for sandbox testing */
+static int lvds_codec_read_edid(struct udevice *dev, u8 *buf, int buf_size)
+{
+ return 0;
+}
+
+static int lvds_codec_get_panel(struct udevice *dev)
+{
+ struct lvds_codec_priv *priv = dev_get_priv(dev);
+ int i, ret;
+
+ u32 num = ofnode_graph_get_port_count(dev_ofnode(dev));
+
+ for (i = 0; i < num; i++) {
+ ofnode remote = ofnode_graph_get_remote_node(dev_ofnode(dev),
i, -1);
+
+ ret = uclass_get_device_by_of_offset(UCLASS_PANEL,
+ ofnode_to_offset(remote),
+ &priv->panel);
+ if (!ret)
+ return 0;
+ }
+
+ /* If this point is reached, no panels were found */
+ return -ENODEV;
+}
+
+static int lvds_codec_probe(struct udevice *dev)
+{
+ struct lvds_codec_priv *priv = dev_get_priv(dev);
+ int ret;
+
+ ret = lvds_codec_get_panel(dev);
+ if (ret) {
+ log_debug("%s: cannot get panel: ret=%d\n", __func__, ret);
+ return log_ret(ret);
+ }
+
+ panel_get_display_timing(priv->panel, &priv->timing);
+
+ ret = gpio_request_by_name(dev, "powerdown-gpios", 0,
+ &priv->powerdown_gpio, GPIOD_IS_OUT);
+ if (ret) {
+ log_debug("%s: could not get powerdown-gpios (%d)\n", __func__,
ret);
+ if (ret != -ENOENT)
+ return log_ret(ret);
+ }
+
+ ret = device_get_supply_regulator(dev, "power-supply", &priv->power);
+ if (ret) {
+ log_debug("%s: power regulator error: %d\n", __func__, ret);
+ if (ret != -ENOENT)
+ return log_ret(ret);
+ }
+
+ return 0;
+}
+
+static const struct video_bridge_ops lvds_codec_ops = {
+ .attach = lvds_codec_attach,
+ .set_backlight = lvds_codec_set_panel,
+ .get_display_timing = lvds_codec_panel_timings,
+ .read_edid = lvds_codec_read_edid,
+};
+
+static const struct udevice_id lvds_codec_ids[] = {
+ { .compatible = "lvds-decoder" },
+ { .compatible = "lvds-encoder" },
+ { }
+};
+
+U_BOOT_DRIVER(lvds_codec) = {
+ .name = "lvds_codec",
+ .id = UCLASS_VIDEO_BRIDGE,
+ .of_match = lvds_codec_ids,
+ .ops = &lvds_codec_ops,
+ .probe = lvds_codec_probe,
+ .priv_auto = sizeof(struct lvds_codec_priv),
+};
--
2.43.0
