drivers/gpu/drm/bridge/lontium-lt8912b.c - linux - Git at Google

 // 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/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/media-bus-format.h>
 #include <linux/regmap.h>

 #include <drm/drm_probe_helper.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_edid.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

 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;
 };

 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;
 };

 /* enable LVDS output with some hardcoded configuration, not required for the HDMI output */
 static int lt8912_write_lvds_config(struct lt8912 *lt)
 {
 	const struct reg_sequence seq[] = {
 		// lvds power up
 		{0x44, 0x30},
 		{0x51, 0x05},

 		// core pll bypass
 		{0x50, 0x24}, // cp=50uA
 		{0x51, 0x2d}, // Pix_clk as reference, second order passive LPF PLL
 		{0x52, 0x04}, // loopdiv=0, use second-order PLL
 		{0x69, 0x0e}, // CP_PRESET_DIV_RATIO
 		{0x69, 0x8e},
 		{0x6a, 0x00},
 		{0x6c, 0xb8}, // RGD_CP_SOFT_K_EN,RGD_CP_SOFT_K[13:8]
 		{0x6b, 0x51},

 		{0x04, 0xfb}, // core pll reset
 		{0x04, 0xff},

 		// scaler bypass
 		{0x7f, 0x00}, // disable scaler
 		{0xa8, 0x13}, // 0x13: JEIDA, 0x33: VESA

 		{0x02, 0xf7}, // lvds pll reset
 		{0x02, 0xff},
 		{0x03, 0xcf},
 		{0x03, 0xff},
 	};

 	return regmap_multi_reg_write(lt->regmap[I2C_MAIN], 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, hsync_activehigh, vsync_activehigh;

 	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;
 	hsync_activehigh = lt->mode.flags & DISPLAY_FLAGS_HSYNC_HIGH;

 	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;
 	vsync_activehigh = lt->mode.flags & DISPLAY_FLAGS_VSYNC_HIGH;

 	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);

 	ret |= regmap_update_bits(lt->regmap[I2C_MAIN], 0xab, BIT(0),
 				  vsync_activehigh ? BIT(0) : 0);
 	ret |= regmap_update_bits(lt->regmap[I2C_MAIN], 0xab, BIT(1),
 				  hsync_activehigh ? BIT(1) : 0);
 	ret |= regmap_update_bits(lt->regmap[I2C_MAIN], 0xb2, BIT(0),
 				  lt->connector.display_info.is_hdmi ? BIT(0) : 0);

 	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 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 = -1;
 	int 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 = devm_mipi_dsi_device_register_full(dev, host, &info);
 	if (IS_ERR(dsi)) {
 		ret = PTR_ERR(dsi);
 		dev_err(dev, "failed to create dsi device (%d)\n", ret);
 		return ret;
 	}

 	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_NO_EOT_PACKET;

 	ret = devm_mipi_dsi_attach(dev, dsi);
 	if (ret < 0) {
 		dev_err(dev, "failed to attach dsi to host\n");
 		return ret;
 	}

 	return 0;
 }

 static void lt8912_bridge_hpd_cb(void *data, enum drm_connector_status status)
 {
 	struct lt8912 *lt = data;

 	if (lt->bridge.dev)
 		drm_helper_hpd_irq_event(lt->bridge.dev);
 }

 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;

 	if (lt->hdmi_port->ops & DRM_BRIDGE_OP_HPD) {
 		drm_bridge_hpd_enable(lt->hdmi_port, lt8912_bridge_hpd_cb, lt);
 		connector->polled = DRM_CONNECTOR_POLL_HPD;
 	} else {
 		connector->polled = DRM_CONNECTOR_POLL_CONNECT |
 				    DRM_CONNECTOR_POLL_DISCONNECT;
 	}

 	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);

 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;

 	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) {
 		lt8912_hard_power_off(lt);

 		if (lt->hdmi_port->ops & DRM_BRIDGE_OP_HPD)
 			drm_bridge_hpd_disable(lt->hdmi_port);

 		drm_connector_unregister(&lt->connector);
 		drm_connector_cleanup(&lt->connector);
 	}
 }

 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 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,
 };

 static int lt8912_parse_dt(struct lt8912 *lt)
 {
 	struct gpio_desc *gp_reset;
 	struct device *dev = lt->dev;
 	int ret;
 	int data_lanes;
 	struct device_node *port_node;

 	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;

 	data_lanes = drm_of_get_data_lanes_count_ep(dev->of_node, 0, -1, 1, 4);
 	if (data_lanes < 0) {
 		dev_err(lt->dev, "%s: Bad data-lanes property\n", __func__);
 		return data_lanes;
 	}

 	lt->data_lanes = data_lanes;

 	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__);
 		return -ENODEV;
 	}

 	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 (!lt->hdmi_port) {
 		ret = -EPROBE_DEFER;
 		dev_err_probe(lt->dev, ret, "%s: Failed to get hdmi port\n", __func__);
 		goto err_free_host_node;
 	}

 	if (!of_device_is_compatible(port_node, "hdmi-connector")) {
 		dev_err(lt->dev, "%s: Failed to get hdmi port\n", __func__);
 		ret = -EINVAL;
 		goto err_free_host_node;
 	}

 	of_node_put(port_node);
 	return 0;

 err_free_host_node:
 	of_node_put(port_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)
 {
 	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;

 	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_add(&lt->bridge);

 	ret = lt8912_attach_dsi(lt);
 	if (ret)
 		goto err_attach;

 	return 0;

 err_attach:
 	drm_bridge_remove(&lt->bridge);
 	lt8912_free_i2c(lt);
 err_i2c:
 	lt8912_put_dt(lt);
 err_dt_parse:
 	return ret;
 }

 static void 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);
 }

 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,
 	},
 	.probe_new = lt8912_probe,
 	.remove = lt8912_remove,
 	.id_table = lt8912_id,
 };
 module_i2c_driver(lt8912_i2c_driver);

 MODULE_AUTHOR("Adrien Grassein <adrien.grassein@gmail.com>");
 MODULE_DESCRIPTION("lt8912 drm driver");
 MODULE_LICENSE("GPL v2");
	// 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/gpio/consumer.h>
	#include <linux/i2c.h>
	#include <linux/media-bus-format.h>
	#include <linux/regmap.h>

	#include <drm/drm_probe_helper.h>
	#include <drm/drm_atomic_helper.h>
	#include <drm/drm_edid.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

	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;
	};

	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;
	};

	/* enable LVDS output with some hardcoded configuration, not required for the HDMI output */
	static int lt8912_write_lvds_config(struct lt8912 *lt)
	{
	const struct reg_sequence seq[] = {
	// lvds power up
	{0x44, 0x30},
	{0x51, 0x05},

	// core pll bypass
	{0x50, 0x24}, // cp=50uA
	{0x51, 0x2d}, // Pix_clk as reference, second order passive LPF PLL
	{0x52, 0x04}, // loopdiv=0, use second-order PLL
	{0x69, 0x0e}, // CP_PRESET_DIV_RATIO
	{0x69, 0x8e},
	{0x6a, 0x00},
	{0x6c, 0xb8}, // RGD_CP_SOFT_K_EN,RGD_CP_SOFT_K[13:8]
	{0x6b, 0x51},

	{0x04, 0xfb}, // core pll reset
	{0x04, 0xff},

	// scaler bypass
	{0x7f, 0x00}, // disable scaler
	{0xa8, 0x13}, // 0x13: JEIDA, 0x33: VESA

	{0x02, 0xf7}, // lvds pll reset
	{0x02, 0xff},
	{0x03, 0xcf},
	{0x03, 0xff},
	};

	return regmap_multi_reg_write(lt->regmap[I2C_MAIN], 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, hsync_activehigh, vsync_activehigh;

	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;
	hsync_activehigh = lt->mode.flags & DISPLAY_FLAGS_HSYNC_HIGH;

	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;
	vsync_activehigh = lt->mode.flags & DISPLAY_FLAGS_VSYNC_HIGH;

	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);

	ret \|= regmap_update_bits(lt->regmap[I2C_MAIN], 0xab, BIT(0),
	vsync_activehigh ? BIT(0) : 0);
	ret \|= regmap_update_bits(lt->regmap[I2C_MAIN], 0xab, BIT(1),
	hsync_activehigh ? BIT(1) : 0);
	ret \|= regmap_update_bits(lt->regmap[I2C_MAIN], 0xb2, BIT(0),
	lt->connector.display_info.is_hdmi ? BIT(0) : 0);

	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 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 = -1;
	int 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 = devm_mipi_dsi_device_register_full(dev, host, &info);
	if (IS_ERR(dsi)) {
	ret = PTR_ERR(dsi);
	dev_err(dev, "failed to create dsi device (%d)\n", ret);
	return ret;
	}

	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_NO_EOT_PACKET;

	ret = devm_mipi_dsi_attach(dev, dsi);
	if (ret < 0) {
	dev_err(dev, "failed to attach dsi to host\n");
	return ret;
	}

	return 0;
	}

	static void lt8912_bridge_hpd_cb(void *data, enum drm_connector_status status)
	{
	struct lt8912 *lt = data;

	if (lt->bridge.dev)
	drm_helper_hpd_irq_event(lt->bridge.dev);
	}

	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;

	if (lt->hdmi_port->ops & DRM_BRIDGE_OP_HPD) {
	drm_bridge_hpd_enable(lt->hdmi_port, lt8912_bridge_hpd_cb, lt);
	connector->polled = DRM_CONNECTOR_POLL_HPD;
	} else {
	connector->polled = DRM_CONNECTOR_POLL_CONNECT \|
	DRM_CONNECTOR_POLL_DISCONNECT;
	}

	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);

	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;

	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) {
	lt8912_hard_power_off(lt);

	if (lt->hdmi_port->ops & DRM_BRIDGE_OP_HPD)
	drm_bridge_hpd_disable(lt->hdmi_port);

	drm_connector_unregister(&lt->connector);
	drm_connector_cleanup(&lt->connector);
	}
	}

	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 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,
	};

	static int lt8912_parse_dt(struct lt8912 *lt)
	{
	struct gpio_desc *gp_reset;
	struct device *dev = lt->dev;
	int ret;
	int data_lanes;
	struct device_node *port_node;

	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;

	data_lanes = drm_of_get_data_lanes_count_ep(dev->of_node, 0, -1, 1, 4);
	if (data_lanes < 0) {
	dev_err(lt->dev, "%s: Bad data-lanes property\n", __func__);
	return data_lanes;
	}

	lt->data_lanes = data_lanes;

	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__);
	return -ENODEV;
	}

	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 (!lt->hdmi_port) {
	ret = -EPROBE_DEFER;
	dev_err_probe(lt->dev, ret, "%s: Failed to get hdmi port\n", __func__);
	goto err_free_host_node;
	}

	if (!of_device_is_compatible(port_node, "hdmi-connector")) {
	dev_err(lt->dev, "%s: Failed to get hdmi port\n", __func__);
	ret = -EINVAL;
	goto err_free_host_node;
	}

	of_node_put(port_node);
	return 0;

	err_free_host_node:
	of_node_put(port_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)
	{
	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;

	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_add(&lt->bridge);

	ret = lt8912_attach_dsi(lt);
	if (ret)
	goto err_attach;

	return 0;

	err_attach:
	drm_bridge_remove(&lt->bridge);
	lt8912_free_i2c(lt);
	err_i2c:
	lt8912_put_dt(lt);
	err_dt_parse:
	return ret;
	}

	static void 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);
	}

	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,
	},
	.probe_new = lt8912_probe,
	.remove = lt8912_remove,
	.id_table = lt8912_id,
	};
	module_i2c_driver(lt8912_i2c_driver);

	MODULE_AUTHOR("Adrien Grassein <adrien.grassein@gmail.com>");
	MODULE_DESCRIPTION("lt8912 drm driver");
	MODULE_LICENSE("GPL v2");