[PATCH v6 0/2] Add Lontium LT9611C(EX/UXD) MIPI DSI to HDMI driver

[PATCH v6 0/2] Add Lontium LT9611C(EX/UXD) MIPI DSI to HDMI driver

[syyang]

From: Sunyun Yang <syyang@lontium.com>

This series introduces:
- A device tree binding YAML file describing the hardware
- A new DRM bridge driver implementing the basic functionality

LT9611C(EX/UXD) is an I2C-controlled chip that Receiver signal/dual port
mipi dsi and output hdmi, differences in hardware features:
- LT9611C: supports 1-port mipi dsi to hdmi 1.4
- LT9611EX: supports 2-port mipi dsi to hdmi 1.4
- LT9611UXD: supports 2-port mipi dsi to hdmi 1.4/2.0

Signed-off-by: Sunyun Yang<syyang@lontium.com>
---
Changes in v6:
- dt-binding:
 1. sorted the compatible list alphabetically.                     [Dmitry]
- drm/bridge:
- Link to v5: https://lore.kernel.org/lkml/20260507024214.97708-1-syyang@lontium.com/

Changes in v5:
- dt-binding:
- drm/bridge:
 1. use #define FW_FILE  "Lontium/lt9611c_fw.bin" to match linux-firmware    [Dmitry]
 2. add atomic state management
- Link to v4: https://lore.kernel.org/lkml/20260506095100.78998-1-syyang@lontium.com/

Changes in v4:
- dt-binding:
 1. fix commit message                                                    [Krzysztof]
- drm/bridge:
 1. use lt9611c_fw.bin                                                     [Dmitry]
 2. use drm_bridge::next_bridge
 3. use enum lt9611_chip_type
 4. remove *fw from the lt9611c struct
 5. "bool hdmi_connected;" variable add comment
 6. use read_poll_timeout and -ETIMEDOUT in the "lt9611c_read_write_flow" function
 7. replace mutex_lock(&lt9611c->ocm_lock) with guard(mutex)(&lt9611c->ocm_lock) in some place
 8. switch to ARRAY_SIZE instead of specifying lengths directly
 9. use dev_err_probe
 10. add clear functions for AVI and audio infoframes
 11. add DRM_BRIDGE_OP_HDMI  and remove .hpd_notify
 12. remove the sample_rate validation code
 13. fix MODULE_DESCRIPTION
 14. replace "GPL v2" with "GPL"
- Link to v3: https://lore.kernel.org/lkml/20260420061644.1251070-1-syyang@lontium.com/

Changes in v3:
- dt-binding:
 1. lt9611c(ex/uxd) content merged into lontium,lt9611.yaml
- drm/bridge:
 1. Drop the licence text, only use SPDX header
 2. Sort the headers
 3. Use library functions for crc8
 4. Drop i2c_read_byte and i2c_write_byte
 5. Lowercase all hex values
 6. Use paged writes as implemented for LT9611C(EX/UXD)
 7. Drop dev_info, use dev_dbg
 8. Modify lt9611c_get_edid_block, don't store EDID in the long-term structures
 9. Use HDMI audio helpers.
 10. Remove unnecessary flags,Implement proper cleanup path, unwinding resources one by one.
 11. Replace devm_kzalloc with devm_drm_bridge_alloc.
 12. Remove extra kthread.
- Link to v1: https://lore.kernel.org/lkml/20250903123825.1721443-1-syyang@lontium.com/

Changes in v2:
 1. Forget modify code, operation error, Please disregard this submit.

Changes in v1:
- dt-binding:
 1. Submit the first version of the code.
- drm/bridge:
 1. Submit the first version of the code.

---
Sunyun Yang (2):
  dt-bindings: bridge: Add Lontium LT9611C(EX/UXD) MIPI DSI to HDMI
    driver
  drm/bridge: Add Lontium LT9611C(EX/UXD) MIPI DSI to HDMI driver

 .../display/bridge/lontium,lt9611.yaml        |    8 +-
 drivers/gpu/drm/bridge/Kconfig                |   18 +
 drivers/gpu/drm/bridge/Makefile               |    1 +
 drivers/gpu/drm/bridge/lontium-lt9611c.c      | 1241 +++++++++++++++++
 4 files changed, 1266 insertions(+), 2 deletions(-)
 create mode 100644 drivers/gpu/drm/bridge/lontium-lt9611c.c

-- 
2.34.1

[PATCH v6 2/2] drm/bridge: Add Lontium LT9611C(EX/UXD) MIPI DSI to HDMI driver

[syyang]

From: Sunyun Yang <syyang@lontium.com>

LT9611C(EX/UXD) is an I2C-controlled chip that Receiver signal/dual port
mipi dsi and output hdmi, differences in hardware features:
- LT9611C: supports 1-port mipi dsi to hdmi 1.4
- LT9611EX: supports 2-port mipi dsi to hdmi 1.4
- LT9611UXD: supports 2-port mipi dsi to hdmi 1.4/2.0

Signed-off-by: Sunyun Yang <syyang@lontium.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/bridge/Kconfig           |   18 +
 drivers/gpu/drm/bridge/Makefile          |    1 +
 drivers/gpu/drm/bridge/lontium-lt9611c.c | 1241 ++++++++++++++++++++++
 3 files changed, 1260 insertions(+)
 create mode 100644 drivers/gpu/drm/bridge/lontium-lt9611c.c

diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index c3209b0f4678..32b85a2a65d9 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -177,6 +177,24 @@ config DRM_LONTIUM_LT9611
 	  HDMI signals
 	  Please say Y if you have such hardware.
 
+config DRM_LONTIUM_LT9611C
+	tristate "Lontium LT9611C DSI/HDMI bridge"
+	select SND_SOC_HDMI_CODEC if SND_SOC
+	depends on OF
+	select CRC8
+	select FW_LOADER
+	select DRM_PANEL_BRIDGE
+	select DRM_KMS_HELPER
+	select DRM_MIPI_DSI
+	select DRM_DISPLAY_HELPER
+	select DRM_DISPLAY_HDMI_STATE_HELPER
+	select REGMAP_I2C
+	help
+	  Driver for Lontium DSI to HDMI bridge
+	  chip driver that converts dual DSI and I2S to
+	  HDMI signals
+	  Please say Y if you have such hardware.
+
 config DRM_LONTIUM_LT9611UXC
 	tristate "Lontium LT9611UXC 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 beab5b695a6e..92688be9692f 100644
--- a/drivers/gpu/drm/bridge/Makefile
+++ b/drivers/gpu/drm/bridge/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_DRM_ITE_IT6505) += ite-it6505.o
 obj-$(CONFIG_DRM_LONTIUM_LT8912B) += lontium-lt8912b.o
 obj-$(CONFIG_DRM_LONTIUM_LT9211) += lontium-lt9211.o
 obj-$(CONFIG_DRM_LONTIUM_LT9611) += lontium-lt9611.o
+obj-$(CONFIG_DRM_LONTIUM_LT9611C) += lontium-lt9611c.o
 obj-$(CONFIG_DRM_LONTIUM_LT9611UXC) += lontium-lt9611uxc.o
 obj-$(CONFIG_DRM_LONTIUM_LT8713SX) += lontium-lt8713sx.o
 obj-$(CONFIG_DRM_LVDS_CODEC) += lvds-codec.o
diff --git a/drivers/gpu/drm/bridge/lontium-lt9611c.c b/drivers/gpu/drm/bridge/lontium-lt9611c.c
new file mode 100644
index 000000000000..cb584855fd8f
--- /dev/null
+++ b/drivers/gpu/drm/bridge/lontium-lt9611c.c
@@ -0,0 +1,1241 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2026 Lontium Semiconductor, Inc.
+ */
+
+#include <linux/crc8.h>
+#include <linux/firmware.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/media-bus-format.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_graph.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_bridge.h>
+#include <drm/drm_connector.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_edid.h>
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_of.h>
+#include <drm/drm_print.h>
+#include <drm/drm_probe_helper.h>
+#include <drm/display/drm_hdmi_audio_helper.h>
+#include <drm/display/drm_hdmi_state_helper.h>
+#include <sound/hdmi-codec.h>
+
+#define FW_SIZE (64 * 1024)
+#define LT_PAGE_SIZE 256
+#define FW_FILE  "Lontium/lt9611c_fw.bin"
+#define LT9611C_CRC_POLYNOMIAL 0x31
+#define LT9611C_PAGE_CONTROL 0xff
+
+enum lt9611_chip_type {
+	CHIP_LT9611C = 0,
+	CHIP_LT9611EX,
+	CHIP_LT9611UXD,
+};
+
+struct lt9611c {
+	struct device *dev;
+	struct i2c_client *client;
+	struct drm_bridge bridge;
+	struct regmap *regmap;
+	/* Protects all accesses to registers by stopping the on-chip MCU */
+	struct mutex ocm_lock;
+	struct work_struct work;
+	struct device_node *dsi0_node;
+	struct device_node *dsi1_node;
+	struct mipi_dsi_device *dsi0;
+	struct mipi_dsi_device *dsi1;
+	struct gpio_desc *reset_gpio;
+	struct regulator_bulk_data supplies[2];
+	int fw_version;
+	/* Chip variant: C/EX/UXD */
+	enum lt9611_chip_type chip_type;
+	 /* HDMI cable connection status */
+	bool hdmi_connected;
+};
+
+DECLARE_CRC8_TABLE(lt9611c_crc8_table);
+
+static const struct regmap_range_cfg lt9611c_ranges[] = {
+	{
+		.name = "register_range",
+		.range_min =  0,
+		.range_max = 0xfe9c,
+		.selector_reg = LT9611C_PAGE_CONTROL,
+		.selector_mask = 0xff,
+		.selector_shift = 0,
+		.window_start = 0,
+		.window_len = 0x100,
+	},
+};
+
+static const struct regmap_config lt9611c_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = 0xfe9c,
+	.ranges = lt9611c_ranges,
+	.num_ranges = ARRAY_SIZE(lt9611c_ranges),
+};
+
+static int lt9611c_read_write_flow(struct lt9611c *lt9611c, u8 *params,
+				   unsigned int param_count, u8 *return_buffer,
+				   unsigned int return_count)
+{
+	int ret;
+	unsigned int i;
+	unsigned int temp;
+	unsigned int max_params = 0xe0dd - 0xe0b0 + 1;
+
+	regmap_write(lt9611c->regmap, 0xe0de, 0x01);
+
+	ret = regmap_read_poll_timeout(lt9611c->regmap, 0xe0ae, temp,
+				       temp == 0x01, 1000, 100 * 1000);
+	if (ret)
+		return -ETIMEDOUT;
+
+	for (i = 0; i < param_count && i < max_params; i++)
+		regmap_write(lt9611c->regmap, 0xe0b0 + i, params[i]);
+
+	regmap_write(lt9611c->regmap, 0xe0de, 0x02);
+
+	ret = regmap_read_poll_timeout(lt9611c->regmap, 0xe0ae, temp,
+				       temp == 0x02, 1000, 100 * 1000);
+	if (ret)
+		return -ETIMEDOUT;
+
+	return regmap_bulk_read(lt9611c->regmap, 0xe085, return_buffer,
+				return_count);
+}
+
+static void lt9611c_config_parameters(struct lt9611c *lt9611c)
+{
+	const struct reg_sequence seq_write_paras[] = {
+		REG_SEQ0(0xe0ee, 0x01),
+		REG_SEQ0(0xe103, 0x3f), /*fifo rst*/
+		REG_SEQ0(0xe103, 0xff),
+		REG_SEQ0(0xe05e, 0xc1),
+		REG_SEQ0(0xe058, 0x00),
+		REG_SEQ0(0xe059, 0x50),
+		REG_SEQ0(0xe05a, 0x10),
+		REG_SEQ0(0xe05a, 0x00),
+		REG_SEQ0(0xe058, 0x21),
+	};
+
+	regmap_multi_reg_write(lt9611c->regmap, seq_write_paras, ARRAY_SIZE(seq_write_paras));
+}
+
+static void lt9611c_wren(struct lt9611c *lt9611c)
+{
+	regmap_write(lt9611c->regmap, 0xe05a, 0x04);
+	regmap_write(lt9611c->regmap, 0xe05a, 0x00);
+}
+
+static void lt9611c_wrdi(struct lt9611c *lt9611c)
+{
+	regmap_write(lt9611c->regmap, 0xe05a, 0x08);
+	regmap_write(lt9611c->regmap, 0xe05a, 0x00);
+}
+
+static void lt9611c_erase_op(struct lt9611c *lt9611c, u32 addr)
+{
+	const struct reg_sequence seq_write[] = {
+		REG_SEQ0(0xe0ee, 0x01),
+		REG_SEQ0(0xe05a, 0x04),
+		REG_SEQ0(0xe05a, 0x00),
+		REG_SEQ0(0xe05b, (addr >> 16) & 0xff),
+		REG_SEQ0(0xe05c, (addr >> 8) & 0xff),
+		REG_SEQ0(0xe05d, addr & 0xff),
+		REG_SEQ0(0xe05a, 0x01),
+		REG_SEQ0(0xe05a, 0x00),
+	};
+
+	regmap_multi_reg_write(lt9611c->regmap, seq_write, ARRAY_SIZE(seq_write));
+}
+
+static void read_flash_reg_status(struct lt9611c *lt9611c, unsigned int *status)
+{
+	const struct reg_sequence seq_write[] = {
+		REG_SEQ0(0xe103, 0x3f),
+		REG_SEQ0(0xe103, 0xff),
+		REG_SEQ0(0xe05e, 0x40),
+		REG_SEQ0(0xe056, 0x05),
+		REG_SEQ0(0xe055, 0x25),
+		REG_SEQ0(0xe055, 0x01),
+		REG_SEQ0(0xe058, 0x21),
+	};
+
+	regmap_multi_reg_write(lt9611c->regmap, seq_write, ARRAY_SIZE(seq_write));
+
+	regmap_read(lt9611c->regmap, 0xe05f, status);
+}
+
+static void lt9611c_crc_to_sram(struct lt9611c *lt9611c)
+{
+	const struct reg_sequence seq_write[] = {
+		REG_SEQ0(0xe051, 0x00),
+		REG_SEQ0(0xe055, 0xc0),
+		REG_SEQ0(0xe055, 0x80),
+		REG_SEQ0(0xe05e, 0xc0),
+		REG_SEQ0(0xe058, 0x21),
+	};
+
+	regmap_multi_reg_write(lt9611c->regmap, seq_write, ARRAY_SIZE(seq_write));
+}
+
+static void lt9611c_data_to_sram(struct lt9611c *lt9611c)
+{
+	const struct reg_sequence seq_write[] = {
+		REG_SEQ0(0xe051, 0xff),
+		REG_SEQ0(0xe055, 0x80),
+		REG_SEQ0(0xe05e, 0xc0),
+		REG_SEQ0(0xe058, 0x21),
+	};
+
+	regmap_multi_reg_write(lt9611c->regmap, seq_write, ARRAY_SIZE(seq_write));
+}
+
+static void lt9611c_sram_to_flash(struct lt9611c *lt9611c, size_t addr)
+{
+	const struct reg_sequence seq_write[] = {
+		REG_SEQ0(0xe05b, (addr >> 16) & 0xff),
+		REG_SEQ0(0xe05c, (addr >> 8) & 0xff),
+		REG_SEQ0(0xe05d, addr & 0xff),
+		REG_SEQ0(0xe05a, 0x30),
+		REG_SEQ0(0xe05a, 0x00),
+	};
+
+	regmap_multi_reg_write(lt9611c->regmap, seq_write, ARRAY_SIZE(seq_write));
+}
+
+static void lt9611c_block_erase(struct lt9611c *lt9611c)
+{
+	struct device *dev = lt9611c->dev;
+	int i;
+	unsigned int block_num;
+	unsigned int flash_status = 0;
+	u32 flash_addr = 0;
+
+	for (block_num = 0; block_num < 2; block_num++) {
+		flash_addr = (block_num * 0x008000);
+		lt9611c_erase_op(lt9611c, flash_addr);
+		msleep(100);
+		i = 0;
+		while (1) {
+			read_flash_reg_status(lt9611c, &flash_status);
+			if ((flash_status & 0x01) == 0)
+				break;
+
+			if (i > 50)
+				break;
+
+			i++;
+			msleep(50);
+		}
+	}
+
+	dev_dbg(dev, "erase flash done.\n");
+}
+
+static int lt9611c_write_data(struct lt9611c *lt9611c, const struct firmware *fw, size_t addr)
+{
+	struct device *dev = lt9611c->dev;
+	int ret;
+	unsigned int page = 0, num = 0, i = 0;
+	size_t size, index;
+	const u8 *data;
+	u8 value;
+
+	data = fw->data;
+	size = fw->size;
+	page = (size + LT_PAGE_SIZE - 1) / LT_PAGE_SIZE;
+	if (page * LT_PAGE_SIZE > FW_SIZE) {
+		dev_err(dev, "firmware size out of range\n");
+		return -EINVAL;
+	}
+
+	dev_dbg(dev, "%u pages, total size %zu byte\n", page, size);
+
+	for (num = 0; num < page; num++) {
+		lt9611c_data_to_sram(lt9611c);
+
+		for (i = 0; i < LT_PAGE_SIZE; i++) {
+			index = num * LT_PAGE_SIZE + i;
+			value = (index < size) ? data[index] : 0xff;
+
+			ret = regmap_write(lt9611c->regmap, 0xe059, value);
+			if (ret < 0) {
+				dev_err(dev, "write error at page %u, index %u\n", num, i);
+				return ret;
+			}
+		}
+
+		lt9611c_wren(lt9611c);
+		lt9611c_sram_to_flash(lt9611c, addr);
+
+		addr += LT_PAGE_SIZE;
+	}
+
+	lt9611c_wrdi(lt9611c);
+
+	return 0;
+}
+
+static int lt9611c_write_crc(struct lt9611c *lt9611c, u8 fw_crc, size_t addr)
+{
+	struct device *dev = lt9611c->dev;
+	int ret;
+
+	lt9611c_crc_to_sram(lt9611c);
+	ret = regmap_write(lt9611c->regmap, 0xe059, fw_crc);
+	if (ret < 0) {
+		dev_err(dev, "failed to write crc\n");
+		return ret;
+	}
+
+	lt9611c_wren(lt9611c);
+	lt9611c_sram_to_flash(lt9611c, addr);
+	lt9611c_wrdi(lt9611c);
+
+	dev_dbg(dev, "crc 0x%02x written to flash at addr 0x%zx\n", fw_crc, addr);
+
+	return 0;
+}
+
+static void lt9611c_reset(struct lt9611c *lt9611c)
+{
+	gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
+	msleep(20);
+
+	gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);
+	msleep(20);
+
+	gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
+	msleep(400);
+
+	dev_dbg(lt9611c->dev, "lt9611c reset");
+}
+
+static int lt9611c_upgrade_result(struct lt9611c *lt9611c, u8 fw_crc)
+{
+	struct device *dev = lt9611c->dev;
+	unsigned int crc_result;
+
+	regmap_write(lt9611c->regmap, 0xe0ee, 0x01);
+	regmap_read(lt9611c->regmap, 0xe021, &crc_result);
+
+	if (crc_result != fw_crc) {
+		dev_err(dev, "lt9611c fw upgrade failed, expected crc=0x%02x, read crc=0x%02x\n",
+			fw_crc, crc_result);
+		return -1;
+	}
+
+	dev_dbg(dev, "lt9611c firmware upgrade success, crc=0x%02x\n", crc_result);
+	return 0;
+}
+
+static int lt9611c_firmware_upgrade(struct lt9611c *lt9611c)
+{
+	struct device *dev = lt9611c->dev;
+	const struct firmware *fw;
+	u8 *buffer;
+	size_t total_size = FW_SIZE - 1;
+	u8 fw_crc;
+	int ret;
+
+	/* 1. load firmware */
+	ret = request_firmware(&fw, FW_FILE, dev);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to load '%s'\n", FW_FILE);
+
+	/* 2. check size */
+	if (fw->size > total_size) {
+		dev_err(dev, "firmware too large (%zu > %zu)\n", fw->size, total_size);
+		ret = -EINVAL;
+		goto out_release_fw;
+	}
+	dev_dbg(dev, "firmware size: %zu bytes\n", fw->size);
+
+	/* 3. calculate crc8 */
+	buffer = kzalloc(total_size, GFP_KERNEL);
+	if (!buffer) {
+		ret = -ENOMEM;
+		goto out_release_fw;
+	}
+
+	memset(buffer, 0xff, total_size);
+	memcpy(buffer, fw->data, fw->size);
+
+	fw_crc = crc8(lt9611c_crc8_table, buffer, total_size, 0);
+	kfree(buffer);
+
+	dev_dbg(dev, "firmware crc: 0x%02x\n", fw_crc);
+	dev_dbg(dev, "starting firmware upgrade, size: %zu bytes\n", fw->size);
+
+	/* 4. firmware upgrade */
+	lt9611c_config_parameters(lt9611c);
+	lt9611c_block_erase(lt9611c);
+
+	ret = lt9611c_write_data(lt9611c, fw, 0);
+	if (ret < 0) {
+		dev_err(dev, "failed to write firmware data\n");
+		goto out_release_fw;
+	}
+
+	ret = lt9611c_write_crc(lt9611c, fw_crc, FW_SIZE - 1);
+	if (ret < 0) {
+		dev_err(dev, "failed to write firmware crc\n");
+		goto out_release_fw;
+	}
+
+	/* 5. check upgrade of result */
+	lt9611c_reset(lt9611c);
+	ret = lt9611c_upgrade_result(lt9611c, fw_crc);
+
+out_release_fw:
+	release_firmware(fw);
+	return ret;
+}
+
+static struct lt9611c *bridge_to_lt9611c(struct drm_bridge *bridge)
+{
+	return container_of(bridge, struct lt9611c, bridge);
+}
+
+/*read only*/
+static const struct lt9611c *bridge_to_lt9611c_const(const struct drm_bridge *bridge)
+{
+	return container_of(bridge, const struct lt9611c, bridge);
+}
+
+static void lt9611c_lock(struct lt9611c *lt9611c)
+{
+	mutex_lock(&lt9611c->ocm_lock);
+	regmap_write(lt9611c->regmap, 0xe0ee, 0x01);
+}
+
+static void lt9611c_unlock(struct lt9611c *lt9611c)
+{
+	regmap_write(lt9611c->regmap, 0xe0ee, 0x00);
+	mutex_unlock(&lt9611c->ocm_lock);
+}
+
+static irqreturn_t lt9611c_irq_thread_handler(int irq, void *dev_id)
+{
+	struct lt9611c *lt9611c = dev_id;
+	struct device *dev = lt9611c->dev;
+	int ret;
+	unsigned int irq_status;
+	u8 cmd[5] = {0x52, 0x48, 0x31, 0x3a, 0x00};
+	u8 data[5];
+
+	guard(mutex)(&lt9611c->ocm_lock);
+
+	ret = regmap_read(lt9611c->regmap, 0xe084, &irq_status);
+	if (ret) {
+		dev_err(dev, "failed to read irq status: %d\n", ret);
+		return IRQ_HANDLED;
+	}
+
+	if (!(irq_status & BIT(0)))
+		return IRQ_HANDLED;
+
+	ret = lt9611c_read_write_flow(lt9611c, cmd, ARRAY_SIZE(cmd), data, ARRAY_SIZE(data));
+	if (ret) {
+		dev_err(dev, "failed to read HPD status\n");
+	} else {
+		lt9611c->hdmi_connected = (data[4] == 0x02);
+		dev_dbg(dev, "HDMI %s\n", lt9611c->hdmi_connected ? "connected" : "disconnected");
+	}
+
+	/*Clear interrupt: hardware requires two writes with delay*/
+	regmap_write(lt9611c->regmap, 0xe0df, irq_status & BIT(0));
+	usleep_range(10000, 12000);
+	regmap_write(lt9611c->regmap, 0xe0df, irq_status & (~BIT(0)));
+
+	schedule_work(&lt9611c->work);
+
+	return IRQ_HANDLED;
+}
+
+static void lt9611c_hpd_work(struct work_struct *work)
+{
+	struct lt9611c *lt9611c = container_of(work, struct lt9611c, work);
+	bool connected;
+
+	mutex_lock(&lt9611c->ocm_lock);
+	connected = lt9611c->hdmi_connected;
+	mutex_unlock(&lt9611c->ocm_lock);
+
+	drm_bridge_hpd_notify(&lt9611c->bridge,
+			      connected ? connector_status_connected :
+			      connector_status_disconnected);
+}
+
+static int lt9611c_regulator_init(struct lt9611c *lt9611c)
+{
+	struct device *dev = lt9611c->dev;
+	int ret;
+
+	lt9611c->supplies[0].supply = "vcc";
+	lt9611c->supplies[1].supply = "vdd";
+
+	ret = devm_regulator_bulk_get(dev, 2, lt9611c->supplies);
+
+	return ret;
+}
+
+static struct mipi_dsi_device *lt9611c_attach_dsi(struct lt9611c *lt9611c,
+						  struct device_node *dsi_node)
+{
+	const struct mipi_dsi_device_info info = { "lt9611c", 0, NULL };
+	struct mipi_dsi_device *dsi;
+	struct mipi_dsi_host *host;
+	struct device *dev = lt9611c->dev;
+	int ret;
+
+	host = of_find_mipi_dsi_host_by_node(dsi_node);
+	if (!host)
+		return ERR_PTR(dev_err_probe(dev, -EPROBE_DEFER, "failed to find dsi host\n"));
+
+	dsi = devm_mipi_dsi_device_register_full(dev, host, &info);
+	if (IS_ERR(dsi))
+		return ERR_PTR(dev_err_probe(dev, PTR_ERR(dsi), "failed to create dsi device\n"));
+
+	dsi->lanes = 4;
+	dsi->format = MIPI_DSI_FMT_RGB888;
+	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_SYNC_PULSE |
+			 MIPI_DSI_MODE_VIDEO_HSE;
+
+	ret = devm_mipi_dsi_attach(dev, dsi);
+	if (ret < 0)
+		return ERR_PTR(dev_err_probe(dev, ret, "failed to attach dsi to host\n"));
+
+	return dsi;
+}
+
+static int lt9611c_bridge_attach(struct drm_bridge *bridge,
+				 struct drm_encoder *encoder,
+				 enum drm_bridge_attach_flags flags)
+{
+	struct lt9611c *lt9611c = bridge_to_lt9611c(bridge);
+
+	return drm_bridge_attach(encoder, lt9611c->bridge.next_bridge, bridge, flags);
+}
+
+static enum drm_mode_status
+lt9611c_hdmi_tmds_char_rate_valid(const struct drm_bridge *bridge,
+				  const struct drm_display_mode *mode,
+				  unsigned long long tmds_rate)
+{
+	const struct lt9611c *lt9611c = bridge_to_lt9611c_const(bridge);
+
+	if (lt9611c->chip_type == CHIP_LT9611UXD) {
+		if (tmds_rate > 600000000)
+			return MODE_CLOCK_HIGH;
+
+	} else {
+		if (tmds_rate > 340000000)
+			return MODE_CLOCK_HIGH;
+	}
+
+	if (tmds_rate < 25000000)
+		return MODE_CLOCK_LOW;
+
+	return MODE_OK;
+}
+
+static void lt9611c_video_setup(struct lt9611c *lt9611c,
+				const struct drm_display_mode *mode)
+{
+	struct device *dev = lt9611c->dev;
+	int ret;
+	u32 h_total, hactive, hsync_len, hfront_porch, hback_porch;
+	u32 v_total, vactive, vsync_len, vfront_porch, vback_porch;
+	u8 timing_set_cmd[26] = {0x57, 0x4d, 0x33, 0x3a};
+	u8 return_param[3];
+	u8 framerate;
+	u8 vic = 0x00;
+
+	guard(mutex)(&lt9611c->ocm_lock);
+	h_total = mode->htotal;
+	hactive = mode->hdisplay;
+	hsync_len = mode->hsync_end - mode->hsync_start;
+	hfront_porch = mode->hsync_start - mode->hdisplay;
+	hback_porch = mode->htotal - mode->hsync_end;
+
+	v_total = mode->vtotal;
+	vactive = mode->vdisplay;
+	vsync_len = mode->vsync_end - mode->vsync_start;
+	vfront_porch = mode->vsync_start - mode->vdisplay;
+	vback_porch = mode->vtotal - mode->vsync_end;
+	framerate = drm_mode_vrefresh(mode);
+	vic = drm_match_cea_mode(mode);
+
+	dev_dbg(dev, "hactive=%d, vactive=%d\n", hactive, vactive);
+	dev_dbg(dev, "framerate=%d\n", framerate);
+	dev_dbg(dev, "vic = 0x%02x\n", vic);
+
+	timing_set_cmd[4] = (h_total >> 8) & 0xff;
+	timing_set_cmd[5] = h_total & 0xff;
+	timing_set_cmd[6] = (hactive >> 8) & 0xff;
+	timing_set_cmd[7] = hactive & 0xff;
+	timing_set_cmd[8] = (hfront_porch >> 8) & 0xff;
+	timing_set_cmd[9] = hfront_porch & 0xff;
+	timing_set_cmd[10] = (hsync_len >> 8) & 0xff;
+	timing_set_cmd[11] = hsync_len & 0xff;
+	timing_set_cmd[12] = (hback_porch >> 8) & 0xff;
+	timing_set_cmd[13] = hback_porch & 0xff;
+	timing_set_cmd[14] = (v_total >> 8) & 0xff;
+	timing_set_cmd[15] = v_total & 0xff;
+	timing_set_cmd[16] = (vactive >> 8) & 0xff;
+	timing_set_cmd[17] = vactive & 0xFF;
+	timing_set_cmd[18] = (vfront_porch >> 8) & 0xff;
+	timing_set_cmd[19] = vfront_porch & 0xff;
+	timing_set_cmd[20] = (vsync_len >> 8) & 0xff;
+	timing_set_cmd[21] = vsync_len & 0xff;
+	timing_set_cmd[22] = (vback_porch >> 8) & 0xff;
+	timing_set_cmd[23] = vback_porch & 0xff;
+	timing_set_cmd[24] = framerate;
+	timing_set_cmd[25] = vic;
+
+	ret = lt9611c_read_write_flow(lt9611c,
+				      timing_set_cmd, ARRAY_SIZE(timing_set_cmd),
+				      return_param, ARRAY_SIZE(return_param));
+	if (ret)
+		dev_err(dev, "video set failed\n");
+}
+
+static void lt9611c_bridge_atomic_pre_enable(struct drm_bridge *bridge,
+					     struct drm_atomic_state *state)
+{
+	struct lt9611c *lt9611c = bridge_to_lt9611c(bridge);
+	int ret;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(lt9611c->supplies), lt9611c->supplies);
+	if (ret)
+		dev_err(lt9611c->dev, "regulator bulk enable failed.\n");
+	lt9611c_reset(lt9611c);
+}
+
+static void lt9611c_bridge_atomic_enable(struct drm_bridge *bridge,
+					 struct drm_atomic_state *state)
+{
+	struct lt9611c *lt9611c = bridge_to_lt9611c(bridge);
+	struct drm_connector *connector;
+	struct drm_connector_state *conn_state;
+	struct drm_crtc_state *crtc_state;
+	struct drm_display_mode *mode;
+
+	connector = drm_atomic_get_new_connector_for_encoder(state, bridge->encoder);
+	if (WARN_ON(!connector))
+		return;
+
+	conn_state = drm_atomic_get_new_connector_state(state, connector);
+	if (WARN_ON(!conn_state))
+		return;
+
+	crtc_state = drm_atomic_get_new_crtc_state(state, conn_state->crtc);
+	if (WARN_ON(!crtc_state))
+		return;
+
+	mode = &crtc_state->adjusted_mode;
+
+	lt9611c_video_setup(lt9611c, mode);
+}
+
+static void lt9611c_bridge_atomic_post_disable(struct drm_bridge *bridge,
+					       struct drm_atomic_state *state)
+{
+	struct lt9611c *lt9611c = bridge_to_lt9611c(bridge);
+	int ret;
+
+	ret = regulator_bulk_disable(ARRAY_SIZE(lt9611c->supplies), lt9611c->supplies);
+	if (ret)
+		dev_err(lt9611c->dev, "regulator bulk disable failed.\n");
+	gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);
+}
+
+static enum drm_connector_status
+lt9611c_bridge_detect(struct drm_bridge *bridge, struct drm_connector *connector)
+{
+	struct lt9611c *lt9611c = bridge_to_lt9611c(bridge);
+	struct device *dev = lt9611c->dev;
+	int ret;
+	bool connected = false;
+	u8 cmd[5] = {0x52, 0x48, 0x31, 0x3a, 0x00};
+	u8 data[5];
+
+	guard(mutex)(&lt9611c->ocm_lock);
+
+	ret = lt9611c_read_write_flow(lt9611c, cmd, ARRAY_SIZE(cmd), data, ARRAY_SIZE(data));
+	if (ret)
+		dev_err(dev, "failed to read HPD status (err=%d)\n", ret);
+	else
+		connected = (data[4] == 0x02);
+
+	lt9611c->hdmi_connected = connected;
+
+	return connected ? connector_status_connected :
+				connector_status_disconnected;
+}
+
+static int lt9611c_get_edid_block(void *data, u8 *buf,
+				  unsigned int block, size_t len)
+{
+	struct lt9611c *lt9611c = data;
+	struct device *dev = lt9611c->dev;
+	u8 cmd[5] = {0x52, 0x48, 0x33, 0x3a, 0x00};
+	u8 packet[37];
+	int ret, i, offset = 0;
+
+	if (len != 128)
+		return -EINVAL;
+	guard(mutex)(&lt9611c->ocm_lock);
+
+	for (i = 0; i < 4; i++) {
+		cmd[4] = block * 4 + i;
+		ret = lt9611c_read_write_flow(lt9611c, cmd, ARRAY_SIZE(cmd),
+					      packet, ARRAY_SIZE(packet));
+		if (ret) {
+			dev_err(dev, "Failed to read EDID block %u packet %d\n",
+				block, i);
+			return ret;
+		}
+		memcpy(buf + offset, &packet[5], 32);
+		offset += 32;
+	}
+
+	return 0;
+}
+
+static const struct drm_edid *lt9611c_bridge_edid_read(struct drm_bridge *bridge,
+						       struct drm_connector *connector)
+{
+	struct lt9611c *lt9611c = bridge_to_lt9611c(bridge);
+
+	return drm_edid_read_custom(connector, lt9611c_get_edid_block, lt9611c);
+}
+
+static int lt9611c_hdmi_write_avi_infoframe(struct drm_bridge *bridge,
+					    const u8 *buffer, size_t len)
+{
+	struct lt9611c *lt9611c = bridge_to_lt9611c(bridge);
+	u8 *cmd;
+	u8 data[5];
+	int ret;
+
+	guard(mutex)(&lt9611c->ocm_lock);
+
+	cmd = kmalloc(5 + len, GFP_KERNEL);
+	if (!cmd)
+		return -ENOMEM;
+
+	cmd[0] = 0x57;
+	cmd[1] = 0x48;
+	cmd[2] = 0x35;
+	cmd[3] = 0x3a;
+	cmd[4] = 0x01;/*write avi*/
+	memcpy(cmd + 5, buffer, len);
+
+	ret = lt9611c_read_write_flow(lt9611c, cmd, 5 + len,
+				      data, ARRAY_SIZE(data));
+	kfree(cmd);
+
+	if (ret < 0) {
+		dev_err(lt9611c->dev, "write avi infoframe failed!\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int lt9611c_hdmi_clear_avi_infoframe(struct drm_bridge *bridge)
+{
+	struct lt9611c *lt9611c = bridge_to_lt9611c(bridge);
+	u8 cmd[5] = {0x57, 0x48, 0x42, 0x3a, 0x01};
+	u8 data[5];
+	int ret;
+
+	guard(mutex)(&lt9611c->ocm_lock);
+
+	ret = lt9611c_read_write_flow(lt9611c, cmd, ARRAY_SIZE(cmd),
+				      data, ARRAY_SIZE(data));
+
+	if (ret < 0) {
+		dev_err(lt9611c->dev, "clear avi infoframe failed!\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int lt9611c_hdmi_write_audio_infoframe(struct drm_bridge *bridge,
+					      const u8 *buffer, size_t len)
+{
+	struct lt9611c *lt9611c = bridge_to_lt9611c(bridge);
+	u8 *cmd;
+	u8 data[5];
+	int ret;
+
+	guard(mutex)(&lt9611c->ocm_lock);
+
+	cmd = kmalloc(5 + len, GFP_KERNEL);
+	if (!cmd)
+		return -ENOMEM;
+
+	cmd[0] = 0x57;
+	cmd[1] = 0x48;
+	cmd[2] = 0x35;
+	cmd[3] = 0x3a;
+	cmd[4] = 0x02;/*write audio*/
+	memcpy(cmd + 5, buffer, len);
+
+	ret = lt9611c_read_write_flow(lt9611c, cmd, 5 + len,
+				      data, ARRAY_SIZE(data));
+
+	kfree(cmd);
+
+	if (ret < 0) {
+		dev_err(lt9611c->dev, "write audio infoframe failed!\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int lt9611c_hdmi_clear_audio_infoframe(struct drm_bridge *bridge)
+{
+	struct lt9611c *lt9611c = bridge_to_lt9611c(bridge);
+	u8 cmd[5] = {0x57, 0x48, 0x42, 0x3a, 0x02};
+	u8 data[5];
+	int ret;
+
+	guard(mutex)(&lt9611c->ocm_lock);
+
+	ret = lt9611c_read_write_flow(lt9611c, cmd, ARRAY_SIZE(cmd),
+				      data, ARRAY_SIZE(data));
+
+	if (ret < 0) {
+		dev_err(lt9611c->dev, "clear audio infoframe failed!\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int lt9611c_hdmi_audio_prepare(struct drm_bridge *bridge,
+				      struct drm_connector *connector,
+				      struct hdmi_codec_daifmt *fmt,
+				      struct hdmi_codec_params *hparms)
+{
+	struct lt9611c *lt9611c = bridge_to_lt9611c(bridge);
+	u8 audio_cmd[6] = {0x57, 0x48, 0x36, 0x3a};
+	u8 data[5];
+	int ret;
+
+	if (hparms->sample_width == 32)
+		return -EINVAL;
+
+	switch (fmt->fmt) {
+	case HDMI_I2S:
+		audio_cmd[4] = 0x01;
+		break;
+	case HDMI_SPDIF:
+		audio_cmd[4] = 0x02;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	audio_cmd[5] = hparms->channels;
+	guard(mutex)(&lt9611c->ocm_lock);
+
+	ret = lt9611c_read_write_flow(lt9611c, audio_cmd, sizeof(audio_cmd),
+				      data, sizeof(data));
+	if (ret < 0) {
+		dev_err(lt9611c->dev, "set audio info failed!\n");
+		return ret;
+	}
+
+	return drm_atomic_helper_connector_hdmi_update_audio_infoframe(connector,
+									&hparms->cea);
+}
+
+static void lt9611c_hdmi_audio_shutdown(struct drm_bridge *bridge,
+					struct drm_connector *connector)
+{
+	drm_atomic_helper_connector_hdmi_clear_audio_infoframe(connector);
+}
+
+static int lt9611c_hdmi_audio_startup(struct drm_bridge *bridge,
+				      struct drm_connector *connector)
+{
+	return 0;
+}
+
+static const struct drm_bridge_funcs lt9611c_bridge_funcs = {
+	.attach = lt9611c_bridge_attach,
+	.detect = lt9611c_bridge_detect,
+	.edid_read = lt9611c_bridge_edid_read,
+	.atomic_pre_enable = lt9611c_bridge_atomic_pre_enable,
+	.atomic_enable = lt9611c_bridge_atomic_enable,
+	.atomic_post_disable = lt9611c_bridge_atomic_post_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,
+
+	.hdmi_tmds_char_rate_valid = lt9611c_hdmi_tmds_char_rate_valid,
+	.hdmi_write_avi_infoframe = lt9611c_hdmi_write_avi_infoframe,
+	.hdmi_clear_avi_infoframe = lt9611c_hdmi_clear_avi_infoframe,
+	.hdmi_write_audio_infoframe = lt9611c_hdmi_write_audio_infoframe,
+	.hdmi_clear_audio_infoframe = lt9611c_hdmi_clear_audio_infoframe,
+
+	.hdmi_audio_startup = lt9611c_hdmi_audio_startup,
+	.hdmi_audio_prepare = lt9611c_hdmi_audio_prepare,
+	.hdmi_audio_shutdown = lt9611c_hdmi_audio_shutdown,
+};
+
+static int lt9611c_parse_dt(struct device *dev,
+			    struct lt9611c *lt9611c)
+{
+	lt9611c->dsi0_node = of_graph_get_remote_node(dev->of_node, 0, -1);
+	if (!lt9611c->dsi0_node)
+		return dev_err_probe(dev, -ENODEV, "failed to get remote node for primary dsi\n");
+
+	lt9611c->dsi1_node = of_graph_get_remote_node(dev->of_node, 1, -1);
+
+	return drm_of_find_panel_or_bridge(dev->of_node, 2, -1, NULL, &lt9611c->bridge.next_bridge);
+}
+
+static int lt9611c_gpio_init(struct lt9611c *lt9611c)
+{
+	struct device *dev = lt9611c->dev;
+
+	lt9611c->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(lt9611c->reset_gpio))
+		return dev_err_probe(dev, PTR_ERR(lt9611c->reset_gpio),
+				"failed to acquire reset gpio\n");
+
+	return 0;
+}
+
+static int lt9611c_read_version(struct lt9611c *lt9611c)
+{
+	u8 buf[2];
+	int ret;
+
+	ret = regmap_write(lt9611c->regmap, 0xe0ee, 0x01);
+	if (ret)
+		return ret;
+
+	ret = regmap_bulk_read(lt9611c->regmap, 0xe080, buf, ARRAY_SIZE(buf));
+	if (ret)
+		return ret;
+
+	return (buf[0] << 8) | buf[1];
+}
+
+static int lt9611c_read_chipid(struct lt9611c *lt9611c)
+{
+	struct device *dev = lt9611c->dev;
+	u8 chipid[2];
+	int ret;
+
+	ret = regmap_write(lt9611c->regmap, 0xe0ee, 0x01);
+	if (ret)
+		return ret;
+
+	ret = regmap_bulk_read(lt9611c->regmap, 0xe100, chipid, 2);
+	if (ret)
+		return ret;
+
+	if (chipid[0] != 0x23 || chipid[1] != 0x06) {
+		dev_err(dev, "ChipID: 0x%02x 0x%02x\n", chipid[0], chipid[1]);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static ssize_t lt9611c_firmware_store(struct device *dev, struct device_attribute *attr,
+				      const char *buf, size_t len)
+{
+	struct lt9611c *lt9611c = dev_get_drvdata(dev);
+	int ret;
+
+	lt9611c_lock(lt9611c);
+
+	ret = lt9611c_firmware_upgrade(lt9611c);
+	if (ret < 0)
+		dev_err(dev, "upgrade failure\n");
+
+	lt9611c_unlock(lt9611c);
+
+	return ret < 0 ? ret : len;
+}
+
+static ssize_t lt9611c_firmware_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct lt9611c *lt9611c = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "0x%04x\n", lt9611c->fw_version);
+}
+
+static DEVICE_ATTR_RW(lt9611c_firmware);
+
+static struct attribute *lt9611c_attrs[] = {
+	&dev_attr_lt9611c_firmware.attr,
+	NULL,
+};
+
+static const struct attribute_group lt9611c_attr_group = {
+	.attrs = lt9611c_attrs,
+};
+
+static const struct attribute_group *lt9611c_attr_groups[] = {
+	&lt9611c_attr_group,
+	NULL,
+};
+
+static int lt9611c_probe(struct i2c_client *client)
+{
+	const struct i2c_device_id *id = i2c_client_get_device_id(client);
+	struct lt9611c *lt9611c;
+	struct device *dev = &client->dev;
+	bool fw_updated = false;
+	int ret;
+
+	crc8_populate_msb(lt9611c_crc8_table, LT9611C_CRC_POLYNOMIAL);
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+		return dev_err_probe(dev, -ENODEV, "device doesn't support I2C\n");
+
+	lt9611c = devm_drm_bridge_alloc(dev, struct lt9611c, bridge, &lt9611c_bridge_funcs);
+	if (IS_ERR(lt9611c))
+		return dev_err_probe(dev, PTR_ERR(lt9611c), "drm bridge alloc failed.\n");
+
+	lt9611c->dev = dev;
+	lt9611c->client = client;
+	lt9611c->chip_type = id->driver_data;
+	ret = devm_mutex_init(dev, &lt9611c->ocm_lock);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to init mutex\n");
+
+	lt9611c->regmap = devm_regmap_init_i2c(client, &lt9611c_regmap_config);
+	if (IS_ERR(lt9611c->regmap))
+		return dev_err_probe(dev, PTR_ERR(lt9611c->regmap), "regmap i2c init failed\n");
+
+	ret = lt9611c_parse_dt(dev, lt9611c);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to parse device tree\n");
+
+	ret = lt9611c_gpio_init(lt9611c);
+	if (ret < 0)
+		goto err_of_put;
+
+	ret = lt9611c_regulator_init(lt9611c);
+	if (ret < 0)
+		goto err_of_put;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(lt9611c->supplies), lt9611c->supplies);
+	if (ret)
+		goto err_of_put;
+
+	lt9611c_reset(lt9611c);
+
+	lt9611c_lock(lt9611c);
+
+	ret = lt9611c_read_chipid(lt9611c);
+	if (ret < 0) {
+		dev_err(dev, "failed to read chip id.\n");
+		lt9611c_unlock(lt9611c);
+		goto err_disable_regulators;
+	}
+
+retry:
+	lt9611c->fw_version = lt9611c_read_version(lt9611c);
+	if (lt9611c->fw_version < 0) {
+		dev_err(dev, "failed to read fw version\n");
+		ret = -EOPNOTSUPP;
+		lt9611c_unlock(lt9611c);
+		goto err_disable_regulators;
+
+	} else if (lt9611c->fw_version == 0) {
+		if (!fw_updated) {
+			fw_updated = true;
+			ret = lt9611c_firmware_upgrade(lt9611c);
+			if (ret < 0) {
+				lt9611c_unlock(lt9611c);
+				goto err_disable_regulators;
+			}
+
+			goto retry;
+
+		} else {
+			dev_err(dev, "fw version 0x%04x, update failed\n", lt9611c->fw_version);
+			ret = -EOPNOTSUPP;
+			lt9611c_unlock(lt9611c);
+			goto err_disable_regulators;
+		}
+	}
+
+	lt9611c_unlock(lt9611c);
+	dev_dbg(dev, "current version:0x%04x", lt9611c->fw_version);
+
+	INIT_WORK(&lt9611c->work, lt9611c_hpd_work);
+
+	ret = devm_request_threaded_irq(&client->dev, client->irq, NULL,
+					lt9611c_irq_thread_handler,
+					IRQF_TRIGGER_FALLING |
+					IRQF_ONESHOT |
+					IRQF_NO_AUTOEN,
+					"lt9611c", lt9611c);
+	if (ret) {
+		dev_err(dev, "failed to request irq\n");
+		goto err_disable_regulators;
+	}
+
+	lt9611c->bridge.of_node = client->dev.of_node;
+	lt9611c->bridge.ops = DRM_BRIDGE_OP_DETECT |
+			DRM_BRIDGE_OP_EDID |
+			DRM_BRIDGE_OP_HPD |
+			DRM_BRIDGE_OP_HDMI |
+			DRM_BRIDGE_OP_HDMI_AUDIO;
+	lt9611c->bridge.type = DRM_MODE_CONNECTOR_HDMIA;
+
+	lt9611c->bridge.hdmi_audio_dev = dev;
+	lt9611c->bridge.hdmi_audio_max_i2s_playback_channels = 8;
+	lt9611c->bridge.hdmi_audio_dai_port = 2;
+
+	devm_drm_bridge_add(dev, &lt9611c->bridge);
+
+	/* Attach primary DSI */
+	lt9611c->dsi0 = lt9611c_attach_dsi(lt9611c, lt9611c->dsi0_node);
+	if (IS_ERR(lt9611c->dsi0)) {
+		ret = PTR_ERR(lt9611c->dsi0);
+		goto err_remove_bridge;
+	}
+
+	/* Attach secondary DSI, if specified */
+	if (lt9611c->dsi1_node) {
+		lt9611c->dsi1 = lt9611c_attach_dsi(lt9611c, lt9611c->dsi1_node);
+		if (IS_ERR(lt9611c->dsi1)) {
+			ret = PTR_ERR(lt9611c->dsi1);
+			goto err_remove_bridge;
+		}
+	}
+
+	lt9611c->hdmi_connected = false;
+	i2c_set_clientdata(client, lt9611c);
+	enable_irq(client->irq);
+	lt9611c_reset(lt9611c);
+
+	return 0;
+
+err_remove_bridge:
+	free_irq(client->irq, lt9611c);
+	cancel_work_sync(&lt9611c->work);
+	drm_bridge_remove(&lt9611c->bridge);
+
+err_disable_regulators:
+	regulator_bulk_disable(ARRAY_SIZE(lt9611c->supplies), lt9611c->supplies);
+
+err_of_put:
+	of_node_put(lt9611c->dsi1_node);
+	of_node_put(lt9611c->dsi0_node);
+
+	return ret;
+}
+
+static void lt9611c_remove(struct i2c_client *client)
+{
+	struct lt9611c *lt9611c = i2c_get_clientdata(client);
+
+	free_irq(client->irq, lt9611c);
+	cancel_work_sync(&lt9611c->work);
+	regulator_bulk_disable(ARRAY_SIZE(lt9611c->supplies), lt9611c->supplies);
+	of_node_put(lt9611c->dsi1_node);
+	of_node_put(lt9611c->dsi0_node);
+}
+
+static int lt9611c_bridge_suspend(struct device *dev)
+{
+	struct lt9611c *lt9611c = dev_get_drvdata(dev);
+	int ret;
+
+	dev_dbg(lt9611c->dev, "suspend\n");
+	disable_irq(lt9611c->client->irq);
+	ret = regulator_bulk_disable(ARRAY_SIZE(lt9611c->supplies), lt9611c->supplies);
+	if (ret) {
+		dev_err(lt9611c->dev, "regulator bulk disable failed.\n");
+		return ret;
+	}
+	gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);
+
+	return ret;
+}
+
+static int lt9611c_bridge_resume(struct device *dev)
+{
+	struct lt9611c *lt9611c = dev_get_drvdata(dev);
+	int ret;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(lt9611c->supplies), lt9611c->supplies);
+	if (ret) {
+		dev_err(lt9611c->dev, "regulator bulk enable failed.\n");
+		return ret;
+	}
+	enable_irq(lt9611c->client->irq);
+	lt9611c_reset(lt9611c);
+	dev_dbg(lt9611c->dev, "resume\n");
+
+	return ret;
+}
+
+static const struct dev_pm_ops lt9611c_bridge_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(lt9611c_bridge_suspend,
+				lt9611c_bridge_resume)
+};
+
+static struct i2c_device_id lt9611c_id[] = {
+	/* chip_type */
+	{ "lontium,lt9611c", 0 },
+	{ "lontium,lt9611ex", 1 },
+	{ "lontium,lt9611uxd", 2 },
+	{ /* sentinel */ }
+};
+
+static const struct of_device_id lt9611c_match_table[] = {
+	{ .compatible = "lontium,lt9611c" },
+	{ .compatible = "lontium,lt9611ex" },
+	{ .compatible = "lontium,lt9611uxd" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, lt9611c_match_table);
+
+static struct i2c_driver lt9611c_driver = {
+	.driver = {
+		.name = "lt9611c",
+		.of_match_table = lt9611c_match_table,
+		.pm = &lt9611c_bridge_pm_ops,
+		.dev_groups = lt9611c_attr_groups,
+	},
+	.probe = lt9611c_probe,
+	.remove = lt9611c_remove,
+	.id_table = lt9611c_id,
+};
+module_i2c_driver(lt9611c_driver);
+
+MODULE_AUTHOR("SunYun Yang <syyang@lontium.com>");
+MODULE_DESCRIPTION("Lontium LT9611C(EX/UXD) MIPI DSI to HDMI driver");
+MODULE_LICENSE("GPL");
+MODULE_FIRMWARE(FW_FILE);
+
-- 
2.34.1

Re: [PATCH v6 2/2] drm/bridge: Add Lontium LT9611C(EX/UXD) MIPI DSI to HDMI driver

[Krzysztof Kozlowski]

On 08/05/2026 15:40, syyang@lontium.com wrote:
> +
> +static void lt9611c_reset(struct lt9611c *lt9611c)
> +{
> +	gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
> +	msleep(20);
> +
> +	gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);
> +	msleep(20);
> +
> +	gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);

This is just plain wrong. Why do you assert, then de-assert and then
finally assert AGAIN the reset leaving the device in powerdown stage?

> +	msleep(400);
> +
> +	dev_dbg(lt9611c->dev, "lt9611c reset");

Drop such debug statements. This is some downstream, semi-useless code.
You are not supposed to add debug to every call.


Best regards,
Krzysztof

Re: [PATCH v6 2/2] drm/bridge: Add Lontium LT9611C(EX/UXD) MIPI DSI to HDMI driver

[Sunyun Yang]

Krzysztof Kozlowski <krzk@kernel.org> 于2026年6月25日周四 20:54写道：
>
> On 08/05/2026 15:40, syyang@lontium.com wrote:
> > +
> > +static void lt9611c_reset(struct lt9611c *lt9611c)
> > +{
> > +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
> > +     msleep(20);
> > +
> > +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);
> > +     msleep(20);
> > +
> > +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
>
> This is just plain wrong. Why do you assert, then de-assert and then
> finally assert AGAIN the reset leaving the device in powerdown stage?
>
I am using software to emulate the hardware RESET button on our EVB.
When the hardware RESET button is pressed while our chip is running,
the signal level changes from HIGH to LOW and then back to HIGH.

Of course, we can also use the following:
static void lt9611c_reset(struct lt9611c *lt9611c)
{
    gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);
    msleep(50);
    gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
    msleep(20);
}


> > +     msleep(400);
> > +
> > +     dev_dbg(lt9611c->dev, "lt9611c reset");
>
> Drop such debug statements. This is some downstream, semi-useless code.
> You are not supposed to add debug to every call.
>
it will be fixed in next version.
>
> Best regards,
> Krzysztof

Re: [PATCH v6 2/2] drm/bridge: Add Lontium LT9611C(EX/UXD) MIPI DSI to HDMI driver

[Krzysztof Kozlowski]

On 25/06/2026 15:14, Sunyun Yang wrote:
> Krzysztof Kozlowski <krzk@kernel.org> 于2026年6月25日周四 20:54写道：
>>
>> On 08/05/2026 15:40, syyang@lontium.com wrote:
>>> +
>>> +static void lt9611c_reset(struct lt9611c *lt9611c)
>>> +{
>>> +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
>>> +     msleep(20);
>>> +
>>> +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);
>>> +     msleep(20);
>>> +
>>> +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
>>
>> This is just plain wrong. Why do you assert, then de-assert and then
>> finally assert AGAIN the reset leaving the device in powerdown stage?
>>
> I am using software to emulate the hardware RESET button on our EVB.
> When the hardware RESET button is pressed while our chip is running,
> the signal level changes from HIGH to LOW and then back to HIGH.
> 
> Of course, we can also use the following:
> static void lt9611c_reset(struct lt9611c *lt9611c)
> {
>     gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);
>     msleep(50);
>     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
>     msleep(20);
> }

Makes no sense either and you just did not get the point and did not
answer my question. I asked WHY you leave asserted. Answer "we emulate"
is just plain wrong.

So again please answer:

Why do you leave device with reset asserted?

Best regards,
Krzysztof

Re: [PATCH v6 2/2] drm/bridge: Add Lontium LT9611C(EX/UXD) MIPI DSI to HDMI driver

[Krzysztof Kozlowski]

On 08/05/2026 15:40, syyang@lontium.com wrote:
> +
> +static int lt9611c_probe(struct i2c_client *client)
> +{
> +	const struct i2c_device_id *id = i2c_client_get_device_id(client);
> +	struct lt9611c *lt9611c;
> +	struct device *dev = &client->dev;
> +	bool fw_updated = false;
> +	int ret;
> +
> +	crc8_populate_msb(lt9611c_crc8_table, LT9611C_CRC_POLYNOMIAL);
> +
> +	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
> +		return dev_err_probe(dev, -ENODEV, "device doesn't support I2C\n");
> +
> +	lt9611c = devm_drm_bridge_alloc(dev, struct lt9611c, bridge, &lt9611c_bridge_funcs);
> +	if (IS_ERR(lt9611c))
> +		return dev_err_probe(dev, PTR_ERR(lt9611c), "drm bridge alloc failed.\n");
> +
> +	lt9611c->dev = dev;
> +	lt9611c->client = client;
> +	lt9611c->chip_type = id->driver_data;

Also, NULL pointer exception here. With simple look I found at least two
easy to reproduce and trigger bugs which makes me questioning how did
you test it.


Best regards,
Krzysztof

Re: [PATCH v6 2/2] drm/bridge: Add Lontium LT9611C(EX/UXD) MIPI DSI to HDMI driver

[Sunyun Yang]

Krzysztof Kozlowski <krzk@kernel.org> 于2026年6月25日周四 21:17写道：
>
> On 25/06/2026 15:14, Sunyun Yang wrote:
> > Krzysztof Kozlowski <krzk@kernel.org> 于2026年6月25日周四 20:54写道：
> >>
> >> On 08/05/2026 15:40, syyang@lontium.com wrote:
> >>> +
> >>> +static void lt9611c_reset(struct lt9611c *lt9611c)
> >>> +{
> >>> +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
> >>> +     msleep(20);
> >>> +
> >>> +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);
> >>> +     msleep(20);
> >>> +
> >>> +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
> >>
> >> This is just plain wrong. Why do you assert, then de-assert and then
> >> finally assert AGAIN the reset leaving the device in powerdown stage?
> >>
> > I am using software to emulate the hardware RESET button on our EVB.
> > When the hardware RESET button is pressed while our chip is running,
> > the signal level changes from HIGH to LOW and then back to HIGH.
> >
> > Of course, we can also use the following:
> > static void lt9611c_reset(struct lt9611c *lt9611c)
> > {
> >     gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);
> >     msleep(50);
> >     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
> >     msleep(20);
> > }
>
> Makes no sense either and you just did not get the point and did not
> answer my question. I asked WHY you leave asserted. Answer "we emulate"
> is just plain wrong.
>
> So again please answer:
>
> Why do you leave device with reset asserted?
>

 devicetree:   reset-gpios = <&tlmm 128 GPIO_ACTIVE_HIGH>;

GPIO_ACTIVE_HIGH:

gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);   ------   reset pin
is Low level : Clear the register configuration in the chip to stop
the chip from working.

gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);   ------  reset pin
is high level:  The chip resumes operation.



> Best regards,
> Krzysztof

Re: [PATCH v6 2/2] drm/bridge: Add Lontium LT9611C(EX/UXD) MIPI DSI to HDMI driver

[Sunyun Yang]

Sunyun Yang <syyang@lontium.com> 于2026年6月25日周四 21:26写道：
>
> Krzysztof Kozlowski <krzk@kernel.org> 于2026年6月25日周四 21:17写道：
> >
> > On 25/06/2026 15:14, Sunyun Yang wrote:
> > > Krzysztof Kozlowski <krzk@kernel.org> 于2026年6月25日周四 20:54写道：
> > >>
> > >> On 08/05/2026 15:40, syyang@lontium.com wrote:
> > >>> +
> > >>> +static void lt9611c_reset(struct lt9611c *lt9611c)
> > >>> +{
> > >>> +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
> > >>> +     msleep(20);
> > >>> +
> > >>> +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);
> > >>> +     msleep(20);
> > >>> +
> > >>> +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
> > >>
> > >> This is just plain wrong. Why do you assert, then de-assert and then
> > >> finally assert AGAIN the reset leaving the device in powerdown stage?
> > >>
> > > I am using software to emulate the hardware RESET button on our EVB.
> > > When the hardware RESET button is pressed while our chip is running,
> > > the signal level changes from HIGH to LOW and then back to HIGH.
> > >
> > > Of course, we can also use the following:
> > > static void lt9611c_reset(struct lt9611c *lt9611c)
> > > {
> > >     gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);
> > >     msleep(50);
> > >     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
> > >     msleep(20);
> > > }
> >
> > Makes no sense either and you just did not get the point and did not
> > answer my question. I asked WHY you leave asserted. Answer "we emulate"
> > is just plain wrong.
> >
> > So again please answer:
> >
> > Why do you leave device with reset asserted?
> >
>
>  devicetree:   reset-gpios = <&tlmm 128 GPIO_ACTIVE_HIGH>;
>
> GPIO_ACTIVE_HIGH:
>
> gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);   ------   reset pin
> is Low level : Clear the register configuration in the chip to stop
> the chip from working.
>
> gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);   ------  reset pin
> is high level:  The chip resumes operation.
>
>

Our purpose is: pull the level low to clear the register configuration
in the chip, and then pull it high to allow the MCU inside the chip to
re‑initialize the registers.

>
> > Best regards,
> > Krzysztof

Re: [PATCH v6 2/2] drm/bridge: Add Lontium LT9611C(EX/UXD) MIPI DSI to HDMI driver

[Krzysztof Kozlowski]

On 25/06/2026 15:26, Sunyun Yang wrote:
> Krzysztof Kozlowski <krzk@kernel.org> 于2026年6月25日周四 21:17写道：
>>
>> On 25/06/2026 15:14, Sunyun Yang wrote:
>>> Krzysztof Kozlowski <krzk@kernel.org> 于2026年6月25日周四 20:54写道：
>>>>
>>>> On 08/05/2026 15:40, syyang@lontium.com wrote:
>>>>> +
>>>>> +static void lt9611c_reset(struct lt9611c *lt9611c)
>>>>> +{
>>>>> +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
>>>>> +     msleep(20);
>>>>> +
>>>>> +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);
>>>>> +     msleep(20);
>>>>> +
>>>>> +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
>>>>
>>>> This is just plain wrong. Why do you assert, then de-assert and then
>>>> finally assert AGAIN the reset leaving the device in powerdown stage?
>>>>
>>> I am using software to emulate the hardware RESET button on our EVB.
>>> When the hardware RESET button is pressed while our chip is running,
>>> the signal level changes from HIGH to LOW and then back to HIGH.
>>>
>>> Of course, we can also use the following:
>>> static void lt9611c_reset(struct lt9611c *lt9611c)
>>> {
>>>     gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);
>>>     msleep(50);
>>>     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
>>>     msleep(20);
>>> }
>>
>> Makes no sense either and you just did not get the point and did not
>> answer my question. I asked WHY you leave asserted. Answer "we emulate"
>> is just plain wrong.
>>
>> So again please answer:
>>
>> Why do you leave device with reset asserted?
>>
> 
>  devicetree:   reset-gpios = <&tlmm 128 GPIO_ACTIVE_HIGH>;

That's irrelevant. I do not talk about DT.

Review is happening in specific place - here I question driver code. If
you do not have actual arguments why device is left in reset stage, then
please fix it.


Best regards,
Krzysztof

Re: [PATCH v6 2/2] drm/bridge: Add Lontium LT9611C(EX/UXD) MIPI DSI to HDMI driver

[Krzysztof Kozlowski]

On 25/06/2026 15:40, Sunyun Yang wrote:
> Sunyun Yang <syyang@lontium.com> 于2026年6月25日周四 21:26写道：
>>
>> Krzysztof Kozlowski <krzk@kernel.org> 于2026年6月25日周四 21:17写道：
>>>
>>> On 25/06/2026 15:14, Sunyun Yang wrote:
>>>> Krzysztof Kozlowski <krzk@kernel.org> 于2026年6月25日周四 20:54写道：
>>>>>
>>>>> On 08/05/2026 15:40, syyang@lontium.com wrote:
>>>>>> +
>>>>>> +static void lt9611c_reset(struct lt9611c *lt9611c)
>>>>>> +{
>>>>>> +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
>>>>>> +     msleep(20);
>>>>>> +
>>>>>> +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);
>>>>>> +     msleep(20);
>>>>>> +
>>>>>> +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
>>>>>
>>>>> This is just plain wrong. Why do you assert, then de-assert and then
>>>>> finally assert AGAIN the reset leaving the device in powerdown stage?
>>>>>
>>>> I am using software to emulate the hardware RESET button on our EVB.
>>>> When the hardware RESET button is pressed while our chip is running,
>>>> the signal level changes from HIGH to LOW and then back to HIGH.
>>>>
>>>> Of course, we can also use the following:
>>>> static void lt9611c_reset(struct lt9611c *lt9611c)
>>>> {
>>>>     gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);
>>>>     msleep(50);
>>>>     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
>>>>     msleep(20);
>>>> }
>>>
>>> Makes no sense either and you just did not get the point and did not
>>> answer my question. I asked WHY you leave asserted. Answer "we emulate"
>>> is just plain wrong.
>>>
>>> So again please answer:
>>>
>>> Why do you leave device with reset asserted?
>>>
>>
>>  devicetree:   reset-gpios = <&tlmm 128 GPIO_ACTIVE_HIGH>;
>>
>> GPIO_ACTIVE_HIGH:
>>
>> gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);   ------   reset pin
>> is Low level : Clear the register configuration in the chip to stop
>> the chip from working.
>>
>> gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);   ------  reset pin
>> is high level:  The chip resumes operation.
>>
>>
> 
> Our purpose is: pull the level low to clear the register configuration
> in the chip, and then pull it high to allow the MCU inside the chip to
> re‑initialize the registers.


And you do completely opposite... so that confirms your code is just wrong.


Best regards,
Krzysztof

Re: [PATCH v6 2/2] drm/bridge: Add Lontium LT9611C(EX/UXD) MIPI DSI to HDMI driver

[Dmitry Baryshkov]

On Thu, Jun 25, 2026 at 09:26:47PM +0800, Sunyun Yang wrote:
> Krzysztof Kozlowski <krzk@kernel.org> 于2026年6月25日周四 21:17写道：
> >
> > On 25/06/2026 15:14, Sunyun Yang wrote:
> > > Krzysztof Kozlowski <krzk@kernel.org> 于2026年6月25日周四 20:54写道：
> > >>
> > >> On 08/05/2026 15:40, syyang@lontium.com wrote:
> > >>> +
> > >>> +static void lt9611c_reset(struct lt9611c *lt9611c)
> > >>> +{
> > >>> +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
> > >>> +     msleep(20);
> > >>> +
> > >>> +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);
> > >>> +     msleep(20);
> > >>> +
> > >>> +     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
> > >>
> > >> This is just plain wrong. Why do you assert, then de-assert and then
> > >> finally assert AGAIN the reset leaving the device in powerdown stage?
> > >>
> > > I am using software to emulate the hardware RESET button on our EVB.
> > > When the hardware RESET button is pressed while our chip is running,
> > > the signal level changes from HIGH to LOW and then back to HIGH.
> > >
> > > Of course, we can also use the following:
> > > static void lt9611c_reset(struct lt9611c *lt9611c)
> > > {
> > >     gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);
> > >     msleep(50);
> > >     gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);
> > >     msleep(20);
> > > }
> >
> > Makes no sense either and you just did not get the point and did not
> > answer my question. I asked WHY you leave asserted. Answer "we emulate"
> > is just plain wrong.
> >
> > So again please answer:
> >
> > Why do you leave device with reset asserted?
> >
> 
>  devicetree:   reset-gpios = <&tlmm 128 GPIO_ACTIVE_HIGH>;

It should be GPIO_ACTIVE_LOW, if the pin as active-low.

> 
> GPIO_ACTIVE_HIGH:
> 
> gpiod_set_value_cansleep(lt9611c->reset_gpio, 0);   ------   reset pin
> is Low level : Clear the register configuration in the chip to stop
> the chip from working.
> 
> gpiod_set_value_cansleep(lt9611c->reset_gpio, 1);   ------  reset pin
> is high level:  The chip resumes operation.
> 
> 
> 
> > Best regards,
> > Krzysztof

-- 
With best wishes
Dmitry