[PATCH v5 2/2] drm/bridge: Introduce LT8912B DSI to HDMI bridge

From: Adrien Grassein
Date: Sat Feb 27 2021 - 11:16:10 EST

Lontium LT8912B is a DSI to HDMI bridge.

Signed-off-by: Adrien Grassein <adrien.grassein@xxxxxxxxx>
---
MAINTAINERS | 1 +
drivers/gpu/drm/bridge/Kconfig | 14 +
drivers/gpu/drm/bridge/Makefile | 1 +
drivers/gpu/drm/bridge/lontium-lt8912b.c | 817 +++++++++++++++++++++++
4 files changed, 833 insertions(+)
create mode 100644 drivers/gpu/drm/bridge/lontium-lt8912b.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 6366b8eac3f6..e075a74f57dd 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10464,6 +10464,7 @@ LONTIUM LT8912B MIPI TO HDMI BRIDGE
M: Adrien Grassein <adrien.grassein@xxxxxxxxx>
S: Maintained
F: Documentation/devicetree/bindings/display/bridge/lontium,lt8912b.yaml
+F: drivers/gpu/drm/bridge/lontium-lt8912b.c

LSILOGIC MPT FUSION DRIVERS (FC/SAS/SPI)
M: Sathya Prakash <sathya.prakash@xxxxxxxxxxxx>
diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index e4110d6ca7b3..f2c5ec75d2f5 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -48,6 +48,20 @@ config DRM_DISPLAY_CONNECTOR
on ARM-based platforms. Saying Y here when this driver is not needed
will not cause any issue.

+config DRM_LONTIUM_LT8912B
+ tristate "Lontium LT8912B DSI/HDMI bridge"
+ depends on OF
+ select DRM_PANEL_BRIDGE
+ select DRM_KMS_HELPER
+ select REGMAP_I2C
+ help
+ Driver for Lontium LT8912B DSI to HDMI bridge
+ chip driver.
+ Please say Y if you have such hardware.
+
+ Say M here if you want to support this hardware as a module.
+ The module will be named "lontium-lt8912b".
+
config DRM_LONTIUM_LT9611
tristate "Lontium LT9611 DSI/HDMI bridge"
select SND_SOC_HDMI_CODEC if SND_SOC
diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
index 86e7acc76f8d..756ce401aad3 100644
--- a/drivers/gpu/drm/bridge/Makefile
+++ b/drivers/gpu/drm/bridge/Makefile
@@ -2,6 +2,7 @@
obj-$(CONFIG_DRM_CDNS_DSI) += cdns-dsi.o
obj-$(CONFIG_DRM_CHRONTEL_CH7033) += chrontel-ch7033.o
obj-$(CONFIG_DRM_DISPLAY_CONNECTOR) += display-connector.o
+obj-$(CONFIG_DRM_LONTIUM_LT8912B) += lontium-lt8912b.o
obj-$(CONFIG_DRM_LONTIUM_LT9611) += lontium-lt9611.o
obj-$(CONFIG_DRM_LONTIUM_LT9611UXC) += lontium-lt9611uxc.o
obj-$(CONFIG_DRM_LVDS_CODEC) += lvds-codec.o
diff --git a/drivers/gpu/drm/bridge/lontium-lt8912b.c b/drivers/gpu/drm/bridge/lontium-lt8912b.c
new file mode 100644
index 000000000000..f3ed8d8b7a64
--- /dev/null
+++ b/drivers/gpu/drm/bridge/lontium-lt8912b.c
@@ -0,0 +1,817 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/device.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
+#include <linux/regmap.h>
+
+#include <drm/drm_probe_helper.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_of.h>
+
+#include <video/videomode.h>
+
+#define I2C_MAIN 0
+#define I2C_ADDR_MAIN 0x48
+
+#define I2C_CEC_DSI 1
+#define I2C_ADDR_CEC_DSI 0x49
+
+#define I2C_MAX_IDX 2
+
+#define HPD_WORK_DELAY_MS 1000
+
+struct lt8912 {
+ struct device *dev;
+ struct drm_bridge bridge;
+ struct drm_connector connector;
+
+ struct i2c_client *i2c_client[I2C_MAX_IDX];
+ struct regmap *regmap[I2C_MAX_IDX];
+
+ struct device_node *host_node;
+ struct drm_bridge *hdmi_port;
+
+ struct mipi_dsi_device *dsi;
+
+ struct gpio_desc *gp_reset;
+
+ struct videomode mode;
+
+ u8 data_lanes;
+ bool is_power_on;
+ bool is_attached;
+
+ enum drm_connector_status cable_status;
+ struct workqueue_struct *workq;
+ struct delayed_work lt8912_check_hpd_work_id;
+};
+
+static int lt8912_write_init_config(struct lt8912 *lt)
+{
+ const struct reg_sequence seq[] = {
+ /* Digital clock en*/
+ {0x08, 0xff},
+ {0x09, 0xff},
+ {0x0a, 0xff},
+ {0x0b, 0x7c},
+ {0x0c, 0xff},
+ {0x42, 0x04},
+
+ /*Tx Analog*/
+ {0x31, 0xb1},
+ {0x32, 0xb1},
+ {0x33, 0x0e},
+ {0x37, 0x00},
+ {0x38, 0x22},
+ {0x60, 0x82},
+
+ /*Cbus Analog*/
+ {0x39, 0x45},
+ {0x3a, 0x00},
+ {0x3b, 0x00},
+
+ /*HDMI Pll Analog*/
+ {0x44, 0x31},
+ {0x55, 0x44},
+ {0x57, 0x01},
+ {0x5a, 0x02},
+
+ /*MIPI Analog*/
+ {0x3e, 0xd6},
+ {0x3f, 0xd4},
+ {0x41, 0x3c},
+ {0xB2, 0x00},
+ };
+
+ return regmap_multi_reg_write(lt->regmap[I2C_MAIN], seq, ARRAY_SIZE(seq));
+}
+
+static int lt8912_write_mipi_basic_config(struct lt8912 *lt)
+{
+ const struct reg_sequence seq[] = {
+ {0x12, 0x04},
+ {0x14, 0x00},
+ {0x15, 0x00},
+ {0x1a, 0x03},
+ {0x1b, 0x03},
+ };
+
+ return regmap_multi_reg_write(lt->regmap[I2C_CEC_DSI], seq, ARRAY_SIZE(seq));
+};
+
+static int lt8912_write_dds_config(struct lt8912 *lt)
+{
+ const struct reg_sequence seq[] = {
+ {0x4e, 0xff},
+ {0x4f, 0x56},
+ {0x50, 0x69},
+ {0x51, 0x80},
+ {0x1f, 0x5e},
+ {0x20, 0x01},
+ {0x21, 0x2c},
+ {0x22, 0x01},
+ {0x23, 0xfa},
+ {0x24, 0x00},
+ {0x25, 0xc8},
+ {0x26, 0x00},
+ {0x27, 0x5e},
+ {0x28, 0x01},
+ {0x29, 0x2c},
+ {0x2a, 0x01},
+ {0x2b, 0xfa},
+ {0x2c, 0x00},
+ {0x2d, 0xc8},
+ {0x2e, 0x00},
+ {0x42, 0x64},
+ {0x43, 0x00},
+ {0x44, 0x04},
+ {0x45, 0x00},
+ {0x46, 0x59},
+ {0x47, 0x00},
+ {0x48, 0xf2},
+ {0x49, 0x06},
+ {0x4a, 0x00},
+ {0x4b, 0x72},
+ {0x4c, 0x45},
+ {0x4d, 0x00},
+ {0x52, 0x08},
+ {0x53, 0x00},
+ {0x54, 0xb2},
+ {0x55, 0x00},
+ {0x56, 0xe4},
+ {0x57, 0x0d},
+ {0x58, 0x00},
+ {0x59, 0xe4},
+ {0x5a, 0x8a},
+ {0x5b, 0x00},
+ {0x5c, 0x34},
+ {0x1e, 0x4f},
+ {0x51, 0x00},
+ };
+
+ return regmap_multi_reg_write(lt->regmap[I2C_CEC_DSI], seq, ARRAY_SIZE(seq));
+}
+
+static int lt8912_write_rxlogicres_config(struct lt8912 *lt)
+{
+ int ret;
+
+ ret = regmap_write(lt->regmap[I2C_MAIN], 0x03, 0x7f);
+ usleep_range(10000, 20000);
+ ret |= regmap_write(lt->regmap[I2C_MAIN], 0x03, 0xff);
+
+ return ret;
+};
+
+static int lt8912_write_lvds_config(struct lt8912 *lt)
+{
+ const struct reg_sequence seq[] = {
+ {0x44, 0x30},
+ {0x51, 0x05},
+ {0x50, 0x24},
+ {0x51, 0x2d},
+ {0x52, 0x04},
+ {0x69, 0x0e},
+ {0x69, 0x8e},
+ {0x6a, 0x00},
+ {0x6c, 0xb8},
+ {0x6b, 0x51},
+ {0x04, 0xfb},
+ {0x04, 0xff},
+ {0x7f, 0x00},
+ {0xa8, 0x13},
+ {0x02, 0xf7},
+ {0x02, 0xff},
+ {0x03, 0xcf},
+ {0x03, 0xff},
+ };
+
+ return regmap_multi_reg_write(lt->regmap[I2C_CEC_DSI], seq, ARRAY_SIZE(seq));
+};
+
+static inline struct lt8912 *bridge_to_lt8912(struct drm_bridge *b)
+{
+ return container_of(b, struct lt8912, bridge);
+}
+
+static inline struct lt8912 *connector_to_lt8912(struct drm_connector *c)
+{
+ return container_of(c, struct lt8912, connector);
+}
+
+static const struct regmap_config lt8912_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = 0xff,
+};
+
+static int lt8912_init_i2c(struct lt8912 *lt, struct i2c_client *client)
+{
+ unsigned int i;
+ /*
+ * At this time we only initialize 2 chips, but the lt8912 provides
+ * a third interface for the audio over HDMI configuration.
+ */
+ struct i2c_board_info info[] = {
+ { I2C_BOARD_INFO("lt8912p0", I2C_ADDR_MAIN), },
+ { I2C_BOARD_INFO("lt8912p1", I2C_ADDR_CEC_DSI), },
+ };
+
+ if (!lt)
+ return -ENODEV;
+
+ for (i = 0; i < ARRAY_SIZE(info); i++) {
+ if (i > 0) {
+ lt->i2c_client[i] = i2c_new_dummy_device(client->adapter,
+ info[i].addr);
+ if (IS_ERR(lt->i2c_client[i]))
+ return PTR_ERR(lt->i2c_client[i]);
+ }
+
+ lt->regmap[i] = devm_regmap_init_i2c(lt->i2c_client[i],
+ &lt8912_regmap_config);
+ if (IS_ERR(lt->regmap[i]))
+ return PTR_ERR(lt->regmap[i]);
+ }
+ return 0;
+}
+
+static int lt8912_free_i2c(struct lt8912 *lt)
+{
+ unsigned int i;
+
+ for (i = 1; i < I2C_MAX_IDX; i++)
+ i2c_unregister_device(lt->i2c_client[i]);
+
+ return 0;
+}
+
+static int lt8912_hard_power_on(struct lt8912 *lt)
+{
+ gpiod_set_value_cansleep(lt->gp_reset, 0);
+ msleep(20);
+
+ return 0;
+}
+
+static void lt8912_hard_power_off(struct lt8912 *lt)
+{
+ gpiod_set_value_cansleep(lt->gp_reset, 1);
+ msleep(20);
+ lt->is_power_on = false;
+}
+
+static int lt8912_video_setup(struct lt8912 *lt)
+{
+ u32 hactive, h_total, hpw, hfp, hbp;
+ u32 vactive, v_total, vpw, vfp, vbp;
+ u8 settle = 0x08;
+ int ret;
+
+ if (!lt)
+ return -EINVAL;
+
+ hactive = lt->mode.hactive;
+ hfp = lt->mode.hfront_porch;
+ hpw = lt->mode.hsync_len;
+ hbp = lt->mode.hback_porch;
+ h_total = hactive + hfp + hpw + hbp;
+
+ vactive = lt->mode.vactive;
+ vfp = lt->mode.vfront_porch;
+ vpw = lt->mode.vsync_len;
+ vbp = lt->mode.vback_porch;
+ v_total = vactive + vfp + vpw + vbp;
+
+ if (vactive <= 600)
+ settle = 0x04;
+ else if (vactive == 1080)
+ settle = 0x0a;
+
+ ret = regmap_write(lt->regmap[I2C_CEC_DSI], 0x10, 0x01);
+ ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x11, settle);
+ ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x18, hpw);
+ ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x19, vpw);
+ ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x1c, hactive & 0xff);
+ ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x1d, hactive >> 8);
+
+ ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x2f, 0x0c);
+
+ ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x34, h_total & 0xff);
+ ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x35, h_total >> 8);
+
+ ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x36, v_total & 0xff);
+ ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x37, v_total >> 8);
+
+ ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x38, vbp & 0xff);
+ ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x39, vbp >> 8);
+
+ ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3a, vfp & 0xff);
+ ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3b, vfp >> 8);
+
+ ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3c, hbp & 0xff);
+ ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3d, hbp >> 8);
+
+ ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3e, hfp & 0xff);
+ ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3f, hfp >> 8);
+
+ return ret;
+}
+
+static int lt8912_soft_power_on(struct lt8912 *lt)
+{
+ if (!lt->is_power_on) {
+ u32 lanes = lt->data_lanes;
+
+ lt8912_write_init_config(lt);
+ regmap_write(lt->regmap[I2C_CEC_DSI], 0x13, lanes & 3);
+
+ lt8912_write_mipi_basic_config(lt);
+
+ lt->is_power_on = true;
+ }
+
+ return 0;
+}
+
+static int lt8912_video_on(struct lt8912 *lt)
+{
+ int ret;
+
+ ret = lt8912_video_setup(lt);
+ if (ret < 0)
+ goto end;
+
+ ret = lt8912_write_dds_config(lt);
+ if (ret < 0)
+ goto end;
+
+ ret = lt8912_write_rxlogicres_config(lt);
+ if (ret < 0)
+ goto end;
+
+ ret = lt8912_write_lvds_config(lt);
+ if (ret < 0)
+ goto end;
+
+end:
+ return ret;
+}
+
+
+static enum drm_connector_status lt8912_check_cable_status(struct lt8912 *lt)
+{
+ int ret;
+ unsigned int reg_val;
+
+ ret = regmap_read(lt->regmap[I2C_MAIN], 0xC1, &reg_val);
+ if (ret)
+ return connector_status_unknown;
+
+ if (reg_val & BIT(7))
+ return connector_status_connected;
+
+ return connector_status_disconnected;
+}
+
+static void lt8912_check_hpd_work(struct work_struct *work)
+{
+ struct delayed_work *dw = to_delayed_work(work);
+ struct lt8912 *lt = container_of(dw, struct lt8912,
+ lt8912_check_hpd_work_id);
+ struct drm_connector *connector = &lt->connector;
+
+ enum drm_connector_status current_state = lt8912_check_cable_status(lt);
+
+ if (current_state != lt->cable_status) {
+ drm_kms_helper_hotplug_event(connector->dev);
+ lt->cable_status = current_state;
+ }
+
+ queue_delayed_work(lt->workq,
+ &lt->lt8912_check_hpd_work_id,
+ msecs_to_jiffies(HPD_WORK_DELAY_MS));
+}
+
+static void lt8912_setup_hpd(struct lt8912 *lt)
+{
+ INIT_DELAYED_WORK(&lt->lt8912_check_hpd_work_id,
+ lt8912_check_hpd_work);
+ queue_delayed_work(lt->workq,
+ &lt->lt8912_check_hpd_work_id,
+ msecs_to_jiffies(HPD_WORK_DELAY_MS));
+}
+
+
+static enum drm_connector_status
+lt8912_connector_detect(struct drm_connector *connector, bool force)
+{
+ struct lt8912 *lt = connector_to_lt8912(connector);
+
+ if (lt->hdmi_port->ops & DRM_BRIDGE_OP_DETECT)
+ return drm_bridge_detect(lt->hdmi_port);
+
+ return lt8912_check_cable_status(lt);
+}
+
+static const struct drm_connector_funcs lt8912_connector_funcs = {
+ .detect = lt8912_connector_detect,
+ .fill_modes = drm_helper_probe_single_connector_modes,
+ .destroy = drm_connector_cleanup,
+ .reset = drm_atomic_helper_connector_reset,
+ .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+ .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+static enum drm_mode_status
+lt8912_connector_mode_valid(struct drm_connector *connector,
+ struct drm_display_mode *mode)
+{
+ if (mode->clock > 150000)
+ return MODE_CLOCK_HIGH;
+
+ if (mode->hdisplay > 1920)
+ return MODE_BAD_HVALUE;
+
+ if (mode->vdisplay > 1080)
+ return MODE_BAD_VVALUE;
+
+ return MODE_OK;
+}
+
+static int lt8912_connector_get_modes(struct drm_connector *connector)
+{
+ struct edid *edid;
+ int ret, num = 0;
+ struct lt8912 *lt = connector_to_lt8912(connector);
+ u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;
+
+ edid = drm_bridge_get_edid(lt->hdmi_port, connector);
+ if (edid) {
+ drm_connector_update_edid_property(connector, edid);
+ num = drm_add_edid_modes(connector, edid);
+ } else
+ return ret;
+
+ ret = drm_display_info_set_bus_formats(&connector->display_info,
+ &bus_format, 1);
+ if (ret)
+ num = ret;
+
+ kfree(edid);
+ return num;
+}
+
+static const struct drm_connector_helper_funcs lt8912_connector_helper_funcs = {
+ .get_modes = lt8912_connector_get_modes,
+ .mode_valid = lt8912_connector_mode_valid,
+};
+
+static void lt8912_bridge_mode_set(struct drm_bridge *bridge,
+ const struct drm_display_mode *mode,
+ const struct drm_display_mode *adj)
+{
+ struct lt8912 *lt = bridge_to_lt8912(bridge);
+
+ drm_display_mode_to_videomode(adj, &lt->mode);
+}
+
+static void lt8912_bridge_enable(struct drm_bridge *bridge)
+{
+ struct lt8912 *lt = bridge_to_lt8912(bridge);
+
+ lt8912_video_on(lt);
+}
+
+static int lt8912_attach_dsi(struct lt8912 *lt)
+{
+ struct device *dev = lt->dev;
+ struct mipi_dsi_host *host;
+ struct mipi_dsi_device *dsi;
+ int ret = -1;
+ const struct mipi_dsi_device_info info = { .type = "lt8912",
+ .channel = 0,
+ .node = NULL,
+ };
+
+ host = of_find_mipi_dsi_host_by_node(lt->host_node);
+ if (!host) {
+ dev_err(dev, "failed to find dsi host\n");
+ return -EPROBE_DEFER;
+ }
+
+ dsi = mipi_dsi_device_register_full(host, &info);
+ if (IS_ERR(dsi)) {
+ ret = PTR_ERR(dsi);
+ dev_err(dev, "failed to create dsi device (%d)\n", ret);
+ goto err_dsi_device;
+ }
+
+ lt->dsi = dsi;
+
+ dsi->lanes = lt->data_lanes;
+ dsi->format = MIPI_DSI_FMT_RGB888;
+
+ dsi->mode_flags = MIPI_DSI_MODE_VIDEO |
+ MIPI_DSI_MODE_VIDEO_BURST |
+ MIPI_DSI_MODE_LPM |
+ MIPI_DSI_MODE_EOT_PACKET;
+
+ ret = mipi_dsi_attach(dsi);
+ if (ret < 0) {
+ dev_err(dev, "failed to attach dsi to host\n");
+ goto err_dsi_attach;
+ }
+
+ return 0;
+
+err_dsi_attach:
+ mipi_dsi_device_unregister(dsi);
+err_dsi_device:
+ return ret;
+}
+
+static void lt8912_detach_dsi(struct lt8912 *lt)
+{
+ mipi_dsi_detach(lt->dsi);
+ mipi_dsi_device_unregister(lt->dsi);
+}
+
+static int lt8912_bridge_connector_init(struct drm_bridge *bridge)
+{
+ int ret;
+ struct lt8912 *lt = bridge_to_lt8912(bridge);
+ struct drm_connector *connector = &lt->connector;
+
+ connector->polled = DRM_CONNECTOR_POLL_HPD;
+
+ ret = drm_connector_init(bridge->dev, connector,
+ &lt8912_connector_funcs,
+ lt->hdmi_port->type);
+ if (ret)
+ goto exit;
+
+ drm_connector_helper_add(connector, &lt8912_connector_helper_funcs);
+
+ connector->dpms = DRM_MODE_DPMS_OFF;
+ drm_connector_attach_encoder(connector, bridge->encoder);
+
+ lt8912_setup_hpd(lt);
+
+exit:
+ return ret;
+}
+
+static int lt8912_bridge_attach(struct drm_bridge *bridge,
+ enum drm_bridge_attach_flags flags)
+{
+ struct lt8912 *lt = bridge_to_lt8912(bridge);
+ int ret;
+
+ if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)) {
+ ret = lt8912_bridge_connector_init(bridge);
+ if (ret) {
+ dev_err(lt->dev, "Failed to init bridge ! (%d)\n", ret);
+ return ret;
+ }
+ }
+
+
+ ret = lt8912_hard_power_on(lt);
+ if (ret)
+ return ret;
+
+ ret = lt8912_soft_power_on(lt);
+ if (ret)
+ goto error;
+
+ ret = lt8912_attach_dsi(lt);
+ if (ret)
+ goto error;
+
+ lt->is_attached = true;
+
+ return 0;
+
+error:
+ lt8912_hard_power_off(lt);
+ return ret;
+}
+
+static void lt8912_bridge_detach(struct drm_bridge *bridge)
+{
+ struct lt8912 *lt = bridge_to_lt8912(bridge);
+
+ if (lt->is_attached) {
+ if (lt->hdmi_port->ops & DRM_BRIDGE_OP_HPD)
+ drm_bridge_hpd_disable(lt->hdmi_port);
+ lt8912_detach_dsi(lt);
+ lt8912_hard_power_off(lt);
+ }
+
+ cancel_delayed_work_sync(&lt->lt8912_check_hpd_work_id);
+}
+
+static enum drm_connector_status
+lt8912_bridge_detect(struct drm_bridge *bridge)
+{
+ struct lt8912 *lt = bridge_to_lt8912(bridge);
+
+ if (lt->hdmi_port->ops & DRM_BRIDGE_OP_DETECT)
+ return drm_bridge_detect(lt->hdmi_port);
+
+ return lt8912_check_cable_status(lt);
+}
+
+static struct edid *lt8912_bridge_get_edid(struct drm_bridge *bridge,
+ struct drm_connector *connector)
+{
+ struct lt8912 *lt = bridge_to_lt8912(bridge);
+
+ /*
+ * edid must be read through the ddc bus but it must be
+ * given to the hdmi connector node.
+ */
+ if (lt->hdmi_port->ops & DRM_BRIDGE_OP_EDID)
+ return drm_bridge_get_edid(lt->hdmi_port, connector);
+
+ dev_warn(lt->dev, "The connected bridge does not supports DRM_BRIDGE_OP_EDID\n");
+ return NULL;
+}
+
+static void lt8912_bridge_hpd_enable(struct drm_bridge *bridge)
+{
+ struct lt8912 *lt = bridge_to_lt8912(bridge);
+
+ if (!(lt->hdmi_port->ops & DRM_BRIDGE_OP_EDID))
+ lt8912_setup_hpd(lt);
+}
+
+static const struct drm_bridge_funcs lt8912_bridge_funcs = {
+ .attach = lt8912_bridge_attach,
+ .detach = lt8912_bridge_detach,
+ .mode_set = lt8912_bridge_mode_set,
+ .enable = lt8912_bridge_enable,
+ .detect = lt8912_bridge_detect,
+ .get_edid = lt8912_bridge_get_edid,
+ .hpd_enable = lt8912_bridge_hpd_enable
+};
+
+static int lt8912_parse_dt(struct lt8912 *lt)
+{
+ struct gpio_desc *gp_reset;
+ struct device *dev = lt->dev;
+ int ret = 0;
+ struct device_node *port_node;
+ struct device_node *endpoint;
+
+ gp_reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+ if (IS_ERR(gp_reset)) {
+ ret = PTR_ERR(gp_reset);
+ if (ret != -EPROBE_DEFER)
+ dev_err(dev, "Failed to get reset gpio: %d\n", ret);
+ return ret;
+ }
+ lt->gp_reset = gp_reset;
+
+
+ endpoint = of_graph_get_endpoint_by_regs(dev->of_node, 0, -1);
+ if (IS_ERR(endpoint)) {
+ ret = PTR_ERR(endpoint);
+ goto end;
+ }
+
+ lt->data_lanes = of_property_count_u32_elems(endpoint, "data-lanes");
+ of_node_put(endpoint);
+
+ lt->host_node = of_graph_get_remote_node(dev->of_node, 0, -1);
+ if (!lt->host_node) {
+ dev_err(lt->dev, "%s: Failed to get remote port\n", __func__);
+ ret = -ENODEV;
+ goto end;
+ }
+
+ port_node = of_graph_get_remote_node(dev->of_node, 1, -1);
+ if (!port_node) {
+ dev_err(lt->dev, "%s: Failed to get connector port\n", __func__);
+ ret = -ENODEV;
+ goto err_free_host_node;
+ }
+
+ lt->hdmi_port = of_drm_find_bridge(port_node);
+ if (IS_ERR(lt->hdmi_port)) {
+ dev_err(lt->dev, "%s: Failed to get hdmi port\n", __func__);
+ ret = PTR_ERR(lt->hdmi_port);
+ of_node_put(lt->host_node);
+ goto end;
+ }
+
+ if (!of_device_is_compatible(port_node, "hdmi-connector")) {
+ dev_err(lt->dev, "%s: Failed to get hdmi port\n", __func__);
+ ret = -EINVAL;
+ }
+
+ of_node_put(port_node);
+
+end:
+ return ret;
+
+err_free_host_node:
+ of_node_put(lt->host_node);
+ return ret;
+}
+
+static int lt8912_put_dt(struct lt8912 *lt)
+{
+ of_node_put(lt->host_node);
+ return 0;
+}
+
+static int lt8912_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ static struct lt8912 *lt;
+ int ret = 0;
+ struct device *dev = &client->dev;
+
+ lt = devm_kzalloc(dev, sizeof(struct lt8912), GFP_KERNEL);
+ if (!lt)
+ return -ENOMEM;
+
+ lt->dev = dev;
+ lt->i2c_client[0] = client;
+ lt->cable_status = connector_status_unknown;
+ lt->workq = create_workqueue("lt8912_workq");
+
+ ret = lt8912_parse_dt(lt);
+ if (ret)
+ goto err_dt_parse;
+
+ ret = lt8912_init_i2c(lt, client);
+ if (ret)
+ goto err_i2c;
+
+ i2c_set_clientdata(client, lt);
+
+ lt->bridge.funcs = &lt8912_bridge_funcs;
+ lt->bridge.of_node = dev->of_node;
+ lt->bridge.ops = (DRM_BRIDGE_OP_EDID |
+ DRM_BRIDGE_OP_DETECT |
+ DRM_BRIDGE_OP_HPD);
+
+ drm_bridge_add(&lt->bridge);
+
+ return 0;
+
+err_i2c:
+ lt8912_put_dt(lt);
+err_dt_parse:
+ return ret;
+}
+
+static int lt8912_remove(struct i2c_client *client)
+{
+ struct lt8912 *lt = i2c_get_clientdata(client);
+
+ lt8912_bridge_detach(&lt->bridge);
+ drm_bridge_remove(&lt->bridge);
+ lt8912_free_i2c(lt);
+ lt8912_put_dt(lt);
+ destroy_workqueue(lt->workq);
+ return 0;
+}
+
+static const struct of_device_id lt8912_dt_match[] = {
+ {.compatible = "lontium,lt8912b"},
+ {}
+};
+MODULE_DEVICE_TABLE(of, lt8912_dt_match);
+
+static const struct i2c_device_id lt8912_id[] = {
+ {"lt8912", 0},
+ {},
+};
+MODULE_DEVICE_TABLE(i2c, lt8912_id);
+
+static struct i2c_driver lt8912_i2c_driver = {
+ .driver = {
+ .name = "lt8912",
+ .of_match_table = lt8912_dt_match,
+ .owner = THIS_MODULE,
+ },
+ .probe = lt8912_probe,
+ .remove = lt8912_remove,
+ .id_table = lt8912_id,
+};
+module_i2c_driver(lt8912_i2c_driver);
+
+MODULE_AUTHOR("Adrien Grassein <adrien.grassein@xxxxxxxxx>");
+MODULE_DESCRIPTION("lt8912 drm driver");
+MODULE_LICENSE("GPL v2");
--
2.25.1