[PATCH v2 0/2] Add lontium lt8713sx bridge driver

[PATCH v2 0/2] Add lontium lt8713sx bridge driver

[Vishnu Saini]

The lt8713sx is a Type-C/DP1.4 to Type-C/DP1.4/HDMI2.0 converter,
with three configurable DP1.4/HDMI2.0/DP++ output interfaces and
audio output interface.

This series provides bridge driver and dt bindings for lt8713sx.
The driver is required for firmware upgrade in the bridge chip.

Signed-off-by: Vishnu Saini <vishnu.saini@oss.qualcomm.com>
---
Changes in v2:
- Addressed review comments from V1, majorly:
- Fixed DCO chain.
- Added supply in bindings.
- Handeled deferred probe in lt8713sx driver probe.
- Link to v1: https://lore.kernel.org/r/20251115-lt8713sx-bridge-driver-v1-0-bd5a1c1c730a@oss.qualcomm.com

---
Vishnu Saini (2):
      dt-bindings: bridge: lt8713sx: Add bindings
      drm/bridge: add support for lontium lt8713sx bridge driver

 Documentation/devicetree/bindings/display/bridge/lontium,lt8713sx.yaml |  52 ++++
 drivers/gpu/drm/bridge/Kconfig                                         |  10 +
 drivers/gpu/drm/bridge/Makefile                                        |   1 +
 drivers/gpu/drm/bridge/lontium-lt8713sx.c                              | 713 +++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 776 insertions(+)
---
base-commit: de0d6e19d2ef33ba34be2467ffdf3595da5f5326
change-id: 20251115-lt8713sx-bridge-driver-32704455bc9a

Best regards,
-- 
Vishnu Saini <vishnu.saini@oss.qualcomm.com>

[PATCH v2 1/2] dt-bindings: bridge: lt8713sx: Add bindings

[Vishnu Saini]

Add bindings for lt8713sx.

Co-developed-by: Prahlad Valluru <vvalluru@qti.qualcomm.com>
Signed-off-by: Prahlad Valluru <vvalluru@qti.qualcomm.com>
Signed-off-by: Vishnu Saini <vishnu.saini@oss.qualcomm.com>
---
 Documentation/devicetree/bindings/display/bridge/lontium,lt8713sx.yaml | 52 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/bridge/lontium,lt8713sx.yaml b/Documentation/devicetree/bindings/display/bridge/lontium,lt8713sx.yaml
new file mode 100644
index 000000000000..3fb7e042c688
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/bridge/lontium,lt8713sx.yaml
@@ -0,0 +1,52 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/bridge/lontium,lt8713sx.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Lontium LT8713SX Type-C/DP1.4 to Type-C/DP1.4/HDMI2.0/DP++ bridge-hub
+
+maintainers:
+  - Tony <syyang@lontium.com>
+
+description:
+  The Lontium LT8713SX is a Type-C/DP1.4 to Type-C/DP1.4/HDMI2.0 converter
+  that integrates one DP input and up to three configurable output interfaces
+  (DP1.4 / HDMI2.0 / DP++), with SST/MST functionality and audio support.
+
+properties:
+  compatible:
+    enum:
+      - lontium,lt8713sx
+
+  reg:
+    maxItems: 1
+
+  vcc-supply:
+    description: Regulator for 3.3V vcc.
+
+  vdd-supply:
+    description: Regulator for 1.1V vdd.
+
+  reset-gpios:
+    description: GPIO connected to active high RESET pin.
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        bridge@4f {
+            compatible = "lontium,lt8713sx";
+            reg = <0x4f>;
+            reset-gpios = <&tlmm 6 GPIO_ACTIVE_HIGH>;
+        };
+    };

-- 
2.34.1

Re: [PATCH v2 1/2] dt-bindings: bridge: lt8713sx: Add bindings

[Krzysztof Kozlowski]

On 18/11/2025 05:37, Vishnu Saini wrote:
> +properties:
> +  compatible:
> +    enum:
> +      - lontium,lt8713sx
> +
> +  reg:
> +    maxItems: 1
> +

<form letter>
This is a friendly reminder during the review process.

It seems my or other reviewer's previous comments were not fully
addressed. Maybe the feedback got lost between the quotes, maybe you
just forgot to apply it. Please go back to the previous discussion and
either implement all requested changes or keep discussing them.

Thank you.
</form letter>


Best regards,
Krzysztof

[PATCH v2 2/2] drm/bridge: add support for lontium lt8713sx bridge driver

[Vishnu Saini]

The lt8713sx is a Type-C/DP1.4 to Type-C/DP1.4/HDMI2.0 converter,
with three configurable DP1.4/HDMI2.0/DP++ output interfaces and
audio output interface.

Driver is required for firmware upgrade in the bridge chip.

Co-developed-by: Prahlad Valluru <vvalluru@qti.qualcomm.com>
Signed-off-by: Prahlad Valluru <vvalluru@qti.qualcomm.com>
Signed-off-by: Vishnu Saini <vishnu.saini@oss.qualcomm.com>
---
 drivers/gpu/drm/bridge/Kconfig            |  10 ++
 drivers/gpu/drm/bridge/Makefile           |   1 +
 drivers/gpu/drm/bridge/lontium-lt8713sx.c | 713 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 724 insertions(+)

diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index a250afd8d662..7fef383ed7cb 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -184,6 +184,16 @@ config DRM_LONTIUM_LT9611UXC
 	  HDMI signals
 	  Please say Y if you have such hardware.
 
+config DRM_LONTIUM_LT8713SX
+	tristate "Lontium LT8713SX DP MST bridge"
+	depends on OF
+	select REGMAP_I2C
+	help
+	  Driver for Lontium LT8713SX DP MST bridge
+	  chip firmware upgrade, which converts Type-C/DP1.4
+	  to 3 configurable Type-C/DP1.4/HDMI2.0 outputs
+	  Please say Y if you have such hardware.
+
 config DRM_ITE_IT66121
 	tristate "ITE IT66121 HDMI bridge"
 	depends on OF
diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
index c7dc03182e59..07eeb13fa497 100644
--- a/drivers/gpu/drm/bridge/Makefile
+++ b/drivers/gpu/drm/bridge/Makefile
@@ -16,6 +16,7 @@ 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_LT9611UXC) += lontium-lt9611uxc.o
+obj-$(CONFIG_DRM_LONTIUM_LT8713SX) += lontium-lt8713sx.o
 obj-$(CONFIG_DRM_LVDS_CODEC) += lvds-codec.o
 obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.o
 obj-$(CONFIG_DRM_MICROCHIP_LVDS_SERIALIZER) += microchip-lvds.o
diff --git a/drivers/gpu/drm/bridge/lontium-lt8713sx.c b/drivers/gpu/drm/bridge/lontium-lt8713sx.c
new file mode 100644
index 000000000000..a5aed2474a2e
--- /dev/null
+++ b/drivers/gpu/drm/bridge/lontium-lt8713sx.c
@@ -0,0 +1,713 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#include <linux/firmware.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.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 <linux/wait.h>
+#include <linux/workqueue.h>
+
+#define FW_FILE "lt8713sx_fw.bin"
+
+#define LT8713SX_PAGE_SIZE 256
+#define FW_12K_SIZE        (12  * 1024)
+#define FW_64K_SIZE        (64  * 1024)
+#define FW_256K_SIZE       (256 * 1024)
+
+struct crc_config {
+	u8 width;
+	u32 poly;
+	u32 crc_init;
+	u32 xor_out;
+	bool ref_in;
+	bool ref_out;
+};
+
+struct lt8713sx {
+	struct device *dev;
+
+	struct regmap *regmap;
+	/* Protects all accesses to registers by stopping the on-chip MCU */
+	struct mutex ocm_lock;
+
+	struct gpio_desc *reset_gpio;
+	struct gpio_desc *enable_gpio;
+
+	struct regulator_bulk_data supplies[2];
+
+	struct i2c_client *client;
+	const struct firmware *fw;
+
+	u8 *fw_buffer;
+
+	u32 main_crc_value;
+	u32 bank_crc_value[17];
+
+	int bank_num;
+};
+
+static void lt8713sx_reset(struct lt8713sx *lt8713sx);
+
+static const struct regmap_range lt8713sx_ranges[] = {
+	{
+		.range_min = 0,
+		.range_max = 0xffff
+	},
+};
+
+static const struct regmap_access_table lt8713sx_table = {
+	.yes_ranges = lt8713sx_ranges,
+	.n_yes_ranges = ARRAY_SIZE(lt8713sx_ranges),
+};
+
+static const struct regmap_config lt8713sx_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.volatile_table = &lt8713sx_table,
+	.cache_type = REGCACHE_NONE,
+};
+
+static void lt8713sx_i2c_enable(struct lt8713sx *lt8713sx)
+{
+	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
+	regmap_write(lt8713sx->regmap, 0xee, 0x01);
+}
+
+static void lt8713sx_i2c_disable(struct lt8713sx *lt8713sx)
+{
+	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
+	regmap_write(lt8713sx->regmap, 0xee, 0x00);
+}
+
+static unsigned int bits_reverse(u32 in_val, u8 bits)
+{
+	u32 out_val = 0;
+	u8 i;
+
+	for (i = 0; i < bits; i++) {
+		if (in_val & (1 << i))
+			out_val |= 1 << (bits - 1 - i);
+	}
+
+	return out_val;
+}
+
+static unsigned int get_crc(struct crc_config crc_cfg, const  u8 *buf, u64 buf_len)
+{
+	u8 width    = crc_cfg.width;
+	u32  poly   = crc_cfg.poly;
+	u32  crc    = crc_cfg.crc_init;
+	u32  xorout = crc_cfg.xor_out;
+	bool refin  = crc_cfg.ref_in;
+	bool refout = crc_cfg.ref_out;
+	u8 n;
+	u32  bits;
+	u32  data;
+	u8 i;
+
+	n    =  (width < 8) ? 0 : (width - 8);
+	crc  =  (width < 8) ? (crc << (8 - width)) : crc;
+	bits =  (width < 8) ? 0x80 : (1 << (width - 1));
+	poly =  (width < 8) ? (poly << (8 - width)) : poly;
+
+	while (buf_len--) {
+		data = *(buf++);
+		if (refin)
+			data = bits_reverse(data, 8);
+		crc ^= (data << n);
+		for (i = 0; i < 8; i++) {
+			if (crc & bits)
+				crc = (crc << 1) ^ poly;
+			else
+				crc = crc << 1;
+		}
+	}
+	crc = (width < 8) ? (crc >> (8 - width)) : crc;
+	if (refout)
+		crc = bits_reverse(crc, width);
+	crc ^= xorout;
+
+	return (crc & ((2 << (width - 1)) - 1));
+}
+
+static u32 calculate_64K_crc(const u8 *upgrade_data, u64 len)
+{
+	struct crc_config crc_cfg = {
+		.width = 8,
+		.poly  = 0x31,
+		.crc_init = 0,
+		.xor_out = 0,
+		.ref_out = false,
+		.ref_in = false,
+	};
+	u64 crc_size = FW_64K_SIZE - 1;
+	u8 default_val = 0xFF;
+
+	crc_cfg.crc_init = get_crc(crc_cfg, upgrade_data, len);
+
+	crc_size -= len;
+	while (crc_size--)
+		crc_cfg.crc_init = get_crc(crc_cfg, &default_val, 1);
+
+	return crc_cfg.crc_init;
+}
+
+static u32 calculate_12K_crc(const u8 *upgrade_data, u64 len)
+{
+	struct crc_config crc_cfg = {
+		.width = 8,
+		.poly  = 0x31,
+		.crc_init = 0,
+		.xor_out = 0,
+		.ref_out = false,
+		.ref_in = false,
+	};
+	u64 crc_size = FW_12K_SIZE;
+	u8 default_val = 0xFF;
+
+	crc_cfg.crc_init = get_crc(crc_cfg, upgrade_data, len);
+
+	crc_size -= len;
+	while (crc_size--)
+		crc_cfg.crc_init = get_crc(crc_cfg, &default_val, 1);
+
+	return crc_cfg.crc_init;
+}
+
+static int lt8713sx_prepare_firmware_data(struct lt8713sx *lt8713sx)
+{
+	int ret = 0;
+
+	ret = request_firmware(&lt8713sx->fw, FW_FILE, lt8713sx->dev);
+	if (ret < 0) {
+		pr_err("request firmware failed\n");
+		return ret;
+	}
+
+	pr_debug("Firmware size: %zu bytes\n", lt8713sx->fw->size);
+
+	if (lt8713sx->fw->size > FW_256K_SIZE - 1) {
+		pr_err("Firmware size exceeds 256KB limit\n");
+		release_firmware(lt8713sx->fw);
+		return -EINVAL;
+	}
+
+	lt8713sx->fw_buffer = kzalloc(FW_256K_SIZE, GFP_KERNEL);
+	if (!lt8713sx->fw_buffer) {
+		release_firmware(lt8713sx->fw);
+		return -ENOMEM;
+	}
+
+	memset(lt8713sx->fw_buffer, 0xFF, FW_256K_SIZE);
+
+	if (lt8713sx->fw->size < FW_64K_SIZE) {
+		/*TODO: CRC should be calculated with 0xff also */
+		memcpy(lt8713sx->fw_buffer, lt8713sx->fw->data, lt8713sx->fw->size);
+		lt8713sx->fw_buffer[FW_64K_SIZE - 1] =
+				calculate_64K_crc(lt8713sx->fw->data, lt8713sx->fw->size);
+		lt8713sx->main_crc_value = lt8713sx->fw_buffer[FW_64K_SIZE - 1];
+		pr_debug("Main Firmware Data  Crc=0x%02X\n", lt8713sx->main_crc_value);
+
+	} else {
+		//main firmware
+		memcpy(lt8713sx->fw_buffer, lt8713sx->fw->data, FW_64K_SIZE - 1);
+		lt8713sx->fw_buffer[FW_64K_SIZE - 1] =
+				calculate_64K_crc(lt8713sx->fw_buffer, FW_64K_SIZE - 1);
+		lt8713sx->main_crc_value = lt8713sx->fw_buffer[FW_64K_SIZE - 1];
+		pr_debug("Main Firmware Data  Crc=0x%02X\n", lt8713sx->main_crc_value);
+
+		//bank firmware
+		memcpy(lt8713sx->fw_buffer + FW_64K_SIZE,
+		       lt8713sx->fw->data + FW_64K_SIZE,
+		       lt8713sx->fw->size - FW_64K_SIZE);
+
+		lt8713sx->bank_num = (lt8713sx->fw->size - FW_64K_SIZE + FW_12K_SIZE - 1) /
+					FW_12K_SIZE;
+		pr_debug("Bank Number Total is %d.\n", lt8713sx->bank_num);
+
+		for (int i = 0; i < lt8713sx->bank_num; i++) {
+			lt8713sx->bank_crc_value[i] =
+				calculate_12K_crc(lt8713sx->fw_buffer + FW_64K_SIZE +
+						  i * FW_12K_SIZE,
+						  FW_12K_SIZE);
+			pr_debug("Bank number:%d; Firmware Data  Crc:0x%02X\n",
+				 i, lt8713sx->bank_crc_value[i]);
+		}
+	}
+	return 0;
+}
+
+static void lt8713sx_config_parameters(struct lt8713sx *lt8713sx)
+{
+	regmap_write(lt8713sx->regmap, 0xFF, 0xE0);
+	regmap_write(lt8713sx->regmap, 0xEE, 0x01);
+	regmap_write(lt8713sx->regmap, 0x5E, 0xC1);
+	regmap_write(lt8713sx->regmap, 0x58, 0x00);
+	regmap_write(lt8713sx->regmap, 0x59, 0x50);
+	regmap_write(lt8713sx->regmap, 0x5A, 0x10);
+	regmap_write(lt8713sx->regmap, 0x5A, 0x00);
+	regmap_write(lt8713sx->regmap, 0x58, 0x21);
+}
+
+static void lt8713sx_wren(struct lt8713sx *lt8713sx)
+{
+	regmap_write(lt8713sx->regmap, 0xff, 0xe1);
+	regmap_write(lt8713sx->regmap, 0x03, 0xbf);
+	regmap_write(lt8713sx->regmap, 0x03, 0xff);
+	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
+	regmap_write(lt8713sx->regmap, 0x5a, 0x04);
+	regmap_write(lt8713sx->regmap, 0x5a, 0x00);
+}
+
+static void lt8713sx_wrdi(struct lt8713sx *lt8713sx)
+{
+	regmap_write(lt8713sx->regmap, 0x5A, 0x08);
+	regmap_write(lt8713sx->regmap, 0x5A, 0x00);
+}
+
+static void lt8713sx_fifo_reset(struct lt8713sx *lt8713sx)
+{
+	regmap_write(lt8713sx->regmap, 0xff, 0xe1);
+	regmap_write(lt8713sx->regmap, 0x03, 0xbf);
+	regmap_write(lt8713sx->regmap, 0x03, 0xff);
+}
+
+static void lt8713sx_disable_sram_write(struct lt8713sx *lt8713sx)
+{
+	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
+	regmap_write(lt8713sx->regmap, 0x55, 0x00);
+}
+
+static void lt8713sx_sram_to_flash(struct lt8713sx *lt8713sx)
+{
+	regmap_write(lt8713sx->regmap, 0x5a, 0x30);
+	regmap_write(lt8713sx->regmap, 0x5a, 0x00);
+}
+
+static void lt8713sx_i2c_to_sram(struct lt8713sx *lt8713sx)
+{
+	regmap_write(lt8713sx->regmap, 0x55, 0x80);
+	regmap_write(lt8713sx->regmap, 0x5e, 0xc0);
+	regmap_write(lt8713sx->regmap, 0x58, 0x21);
+}
+
+static u8 lt8713sx_read_flash_status(struct lt8713sx *lt8713sx)
+{
+	u32 flash_status = 0;
+
+	regmap_write(lt8713sx->regmap,  0xFF, 0xE1);//fifo_rst_n
+	regmap_write(lt8713sx->regmap,  0x03, 0x3F);
+	regmap_write(lt8713sx->regmap,  0x03, 0xFF);
+
+	regmap_write(lt8713sx->regmap,  0xFF, 0xE0);
+	regmap_write(lt8713sx->regmap,  0x5e, 0x40);
+	regmap_write(lt8713sx->regmap,  0x56, 0x05);//opcode=read status register
+	regmap_write(lt8713sx->regmap,  0x55, 0x25);
+	regmap_write(lt8713sx->regmap,  0x55, 0x01);
+	regmap_write(lt8713sx->regmap,  0x58, 0x21);
+
+	regmap_read(lt8713sx->regmap, 0x5f, &flash_status);
+	pr_debug("flash_status:%x\n", flash_status);
+
+	return flash_status;
+}
+
+static void lt8713sx_block_erase(struct lt8713sx *lt8713sx)
+{
+	u32 i = 0;
+	u8 flash_status = 0;
+	u8 blocknum = 0x00;
+	u32 flashaddr = 0x00;
+
+	for (blocknum = 0; blocknum < 8; blocknum++) {
+		flashaddr = blocknum * 0x008000;
+		regmap_write(lt8713sx->regmap,  0xFF, 0xE0);
+		regmap_write(lt8713sx->regmap,  0xEE, 0x01);
+		regmap_write(lt8713sx->regmap,  0x5A, 0x04);
+		regmap_write(lt8713sx->regmap,  0x5A, 0x00);
+		regmap_write(lt8713sx->regmap,  0x5B, flashaddr >> 16);//set flash address[23:16]
+		regmap_write(lt8713sx->regmap,  0x5C, flashaddr >> 8);//set flash address[15:8]
+		regmap_write(lt8713sx->regmap,  0x5D, flashaddr);//set flash address[7:0]
+		regmap_write(lt8713sx->regmap,  0x5A, 0x01);
+		regmap_write(lt8713sx->regmap,  0x5A, 0x00);
+		msleep(100); //delay 100ms
+		i = 0;
+		while (1) {
+			flash_status = lt8713sx_read_flash_status(lt8713sx); //wait erase finish
+			if ((flash_status & 0x01) == 0)
+				break;
+
+			if (i > 50)
+				break;
+
+			i++;
+			msleep(50); //delay 50ms
+		}
+	}
+	pr_debug("erase flash done.\n");
+}
+
+static void lt8713sx_load_main_fw_to_sram(struct lt8713sx *lt8713sx)
+{
+	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
+	regmap_write(lt8713sx->regmap, 0xee, 0x01);
+	regmap_write(lt8713sx->regmap, 0x68, 0x00);
+	regmap_write(lt8713sx->regmap, 0x69, 0x00);
+	regmap_write(lt8713sx->regmap, 0x6a, 0x00);
+	regmap_write(lt8713sx->regmap, 0x65, 0x00);
+	regmap_write(lt8713sx->regmap, 0x66, 0xff);
+	regmap_write(lt8713sx->regmap, 0x67, 0xff);
+	regmap_write(lt8713sx->regmap, 0x6b, 0x00);
+	regmap_write(lt8713sx->regmap, 0x6c, 0x00);
+	regmap_write(lt8713sx->regmap, 0x60, 0x01);
+	msleep(200);
+	regmap_write(lt8713sx->regmap, 0x60, 0x00);
+}
+
+static void lt8713sx_load_bank_fw_to_sram(struct lt8713sx *lt8713sx, u64 addr)
+{
+	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
+	regmap_write(lt8713sx->regmap, 0xee, 0x01);
+	regmap_write(lt8713sx->regmap, 0x68, ((addr & 0xFF0000) >> 16));
+	regmap_write(lt8713sx->regmap, 0x69, ((addr & 0x00FF00) >> 8));
+	regmap_write(lt8713sx->regmap, 0x6a, (addr & 0x0000FF));
+	regmap_write(lt8713sx->regmap, 0x65, 0x00);
+	regmap_write(lt8713sx->regmap, 0x66, 0x30);
+	regmap_write(lt8713sx->regmap, 0x67, 0x00);
+	regmap_write(lt8713sx->regmap, 0x6b, 0x00);
+	regmap_write(lt8713sx->regmap, 0x6c, 0x00);
+	regmap_write(lt8713sx->regmap, 0x60, 0x01);
+	msleep(50);
+	regmap_write(lt8713sx->regmap, 0x60, 0x00);
+}
+
+static int lt8713sx_write_data(struct lt8713sx *lt8713sx, const u8 *data, u64 filesize)
+{
+	int page = 0, num = 0, i = 0, val;
+
+	page = (filesize % LT8713SX_PAGE_SIZE) ?
+			((filesize / LT8713SX_PAGE_SIZE) + 1) : (filesize / LT8713SX_PAGE_SIZE);
+
+	pr_debug("Writing to Sram=%u pages, total size = %llu bytes\n", page, filesize);
+
+	for (num = 0; num < page; num++) {
+		pr_debug("page[%d]\n", num);
+		lt8713sx_i2c_to_sram(lt8713sx);
+
+		for (i = 0; i < LT8713SX_PAGE_SIZE; i++) {
+			if ((num * LT8713SX_PAGE_SIZE + i) < filesize)
+				val = *(data + (num * LT8713SX_PAGE_SIZE + i));
+			else
+				val = 0xFF;
+			regmap_write(lt8713sx->regmap, 0x59, val);
+		}
+
+		lt8713sx_wren(lt8713sx);
+		lt8713sx_sram_to_flash(lt8713sx);
+	}
+
+	lt8713sx_wrdi(lt8713sx);
+	lt8713sx_disable_sram_write(lt8713sx);
+
+	return 0;
+}
+
+static void lt8713sx_main_upgrade_result(struct lt8713sx *lt8713sx)
+{
+	u32 main_crc_result;
+
+	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
+	regmap_read(lt8713sx->regmap, 0x23, &main_crc_result);
+
+	pr_debug("Main CRC HW: 0x%02X\n", main_crc_result);
+	pr_debug("Main CRC FW: 0x%02X\n", lt8713sx->main_crc_value);
+
+	if (main_crc_result == lt8713sx->main_crc_value)
+		pr_debug("Main Firmware Upgrade Success.\n");
+	else
+		pr_err("Main Firmware Upgrade Failed.\n");
+}
+
+static void lt8713sx_bank_upgrade_result(struct lt8713sx *lt8713sx, u8 banknum)
+{
+	u32 bank_crc_result;
+
+	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
+
+	regmap_read(lt8713sx->regmap, 0x23, &bank_crc_result);
+
+	pr_debug("Bank %d CRC Result: 0x%02X\n", banknum, bank_crc_result);
+
+	if (bank_crc_result == lt8713sx->bank_crc_value[banknum])
+		pr_debug("Bank %d Firmware Upgrade Success.\n", banknum);
+	else
+		pr_err("Bank %d Firmware Upgrade Failed.\n", banknum);
+}
+
+static void lt8713sx_bank_result_check(struct lt8713sx *lt8713sx)
+{
+	int i;
+	u64 addr = 0x010000;
+
+	for (i = 0; i < lt8713sx->bank_num; i++) {
+		lt8713sx_load_bank_fw_to_sram(lt8713sx, addr);
+		lt8713sx_bank_upgrade_result(lt8713sx, i);
+		addr += 0x3000;
+	}
+}
+
+static int lt8713sx_firmware_upgrade(struct lt8713sx *lt8713sx)
+{
+	int ret;
+
+	lt8713sx_config_parameters(lt8713sx);
+
+	lt8713sx_block_erase(lt8713sx);
+
+	if (lt8713sx->fw->size < FW_64K_SIZE) {
+		ret = lt8713sx_write_data(lt8713sx, lt8713sx->fw_buffer, FW_64K_SIZE);
+		if (ret < 0) {
+			pr_err("Failed to write firmware data: %d\n", ret);
+			return ret;
+		}
+	} else {
+		ret = lt8713sx_write_data(lt8713sx, lt8713sx->fw_buffer, lt8713sx->fw->size);
+		if (ret < 0) {
+			pr_err("Failed to write firmware data: %d\n", ret);
+			return ret;
+		}
+	}
+
+	pr_debug("Write Data done.\n");
+
+	return 0;
+}
+
+static int lt8713sx_firmware_update(struct lt8713sx *lt8713sx)
+{
+	int ret = 0;
+
+	mutex_lock(&lt8713sx->ocm_lock);
+	lt8713sx_i2c_enable(lt8713sx);
+
+	ret = lt8713sx_prepare_firmware_data(lt8713sx);
+	if (ret < 0) {
+		pr_err("Failed to prepare firmware data: %d\n", ret);
+		goto error;
+	}
+
+	ret = lt8713sx_firmware_upgrade(lt8713sx);
+	if (ret < 0) {
+		pr_err("Upgrade failure.\n");
+		goto error;
+	} else {
+		/* Validate CRC */
+		lt8713sx_load_main_fw_to_sram(lt8713sx);
+		lt8713sx_main_upgrade_result(lt8713sx);
+		lt8713sx_wrdi(lt8713sx);
+		lt8713sx_fifo_reset(lt8713sx);
+		lt8713sx_bank_result_check(lt8713sx);
+		lt8713sx_wrdi(lt8713sx);
+	}
+
+error:
+	lt8713sx_i2c_disable(lt8713sx);
+	if (!ret)
+		lt8713sx_reset(lt8713sx);
+
+	kfree(lt8713sx->fw_buffer);
+	lt8713sx->fw_buffer = NULL;
+
+	if (lt8713sx->fw) {
+		release_firmware(lt8713sx->fw);
+		lt8713sx->fw = NULL;
+	}
+	mutex_unlock(&lt8713sx->ocm_lock);
+
+	return ret;
+}
+
+static void lt8713sx_reset(struct lt8713sx *lt8713sx)
+{
+	pr_debug("reset bridge.\n");
+	gpiod_set_value_cansleep(lt8713sx->reset_gpio, 1);
+	msleep(20);
+
+	gpiod_set_value_cansleep(lt8713sx->reset_gpio, 0);
+	msleep(20);
+
+	gpiod_set_value_cansleep(lt8713sx->reset_gpio, 1);
+	msleep(20);
+	pr_debug("reset done.\n");
+}
+
+static int lt8713sx_regulator_init(struct lt8713sx *lt8713sx)
+{
+	int ret;
+
+	lt8713sx->supplies[0].supply = "vdd";
+	lt8713sx->supplies[1].supply = "vcc";
+
+	ret = devm_regulator_bulk_get(lt8713sx->dev, 2, lt8713sx->supplies);
+	if (ret < 0)
+		return dev_err_probe(lt8713sx->dev, ret, "failed to get regulators\n");
+
+	ret = regulator_set_load(lt8713sx->supplies[0].consumer, 200000);
+	if (ret < 0)
+		return dev_err_probe(lt8713sx->dev, ret, "failed to set regulator load\n");
+
+	return 0;
+}
+
+static int lt8713sx_regulator_enable(struct lt8713sx *lt8713sx)
+{
+	int ret;
+
+	ret = regulator_enable(lt8713sx->supplies[0].consumer);
+	if (ret < 0)
+		return dev_err_probe(lt8713sx->dev, ret, "failed to enable vdd regulator\n");
+
+	usleep_range(1000, 10000);
+
+	ret = regulator_enable(lt8713sx->supplies[1].consumer);
+	if (ret < 0) {
+		regulator_disable(lt8713sx->supplies[0].consumer);
+		return dev_err_probe(lt8713sx->dev, ret, "failed to enable vcc regulator\n");
+	}
+	return 0;
+}
+
+static int lt8713sx_gpio_init(struct lt8713sx *lt8713sx)
+{
+	struct device *dev = lt8713sx->dev;
+
+	lt8713sx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(lt8713sx->reset_gpio))
+		return dev_err_probe(dev, PTR_ERR(lt8713sx->reset_gpio),
+				     "failed to acquire reset gpio\n");
+
+	/* power enable gpio */
+	lt8713sx->enable_gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_HIGH);
+	if (IS_ERR(lt8713sx->enable_gpio))
+		return dev_err_probe(dev, PTR_ERR(lt8713sx->enable_gpio),
+				     "failed to acquire enable gpio\n");
+	return 0;
+}
+
+static ssize_t lt8713sx_firmware_store(struct device *dev,
+				       struct device_attribute *attr,
+				       const char *buf, size_t len)
+{
+	struct lt8713sx *lt8713sx = dev_get_drvdata(dev);
+	int ret;
+
+	ret = lt8713sx_firmware_update(lt8713sx);
+	if (ret < 0)
+		return ret;
+	return len;
+}
+
+static DEVICE_ATTR_WO(lt8713sx_firmware);
+
+static struct attribute *lt8713sx_attrs[] = {
+	&dev_attr_lt8713sx_firmware.attr,
+	NULL,
+};
+
+static const struct attribute_group lt8713sx_attr_group = {
+	.attrs = lt8713sx_attrs,
+};
+
+static const struct attribute_group *lt8713sx_attr_groups[] = {
+	&lt8713sx_attr_group,
+	NULL,
+};
+
+static int lt8713sx_probe(struct i2c_client *client)
+{
+	struct lt8713sx *lt8713sx;
+	struct device *dev = &client->dev;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+		return dev_err_probe(dev, -ENODEV, "device doesn't support I2C\n");
+
+	lt8713sx = devm_kzalloc(dev, sizeof(*lt8713sx), GFP_KERNEL);
+	if (!lt8713sx)
+		return dev_err_probe(dev, -ENOMEM, "failed to allocate lt8713sx struct\n");
+
+	lt8713sx->dev = dev;
+	lt8713sx->client = client;
+	i2c_set_clientdata(client, lt8713sx);
+
+	mutex_init(&lt8713sx->ocm_lock);
+
+	lt8713sx->regmap = devm_regmap_init_i2c(client, &lt8713sx_regmap_config);
+	if (IS_ERR(lt8713sx->regmap))
+		return dev_err_probe(dev, PTR_ERR(lt8713sx->regmap), "regmap i2c init failed\n");
+
+	ret = lt8713sx_gpio_init(lt8713sx);
+	if (ret < 0)
+		goto err_of_put;
+
+	ret = lt8713sx_regulator_init(lt8713sx);
+	if (ret < 0)
+		goto err_of_put;
+
+	ret = lt8713sx_regulator_enable(lt8713sx);
+	if (ret)
+		goto err_of_put;
+
+	lt8713sx_reset(lt8713sx);
+
+	return 0;
+
+err_of_put:
+	return ret;
+}
+
+static void lt8713sx_remove(struct i2c_client *client)
+{
+	struct lt8713sx *lt8713sx = i2c_get_clientdata(client);
+
+	mutex_destroy(&lt8713sx->ocm_lock);
+
+	regulator_bulk_disable(ARRAY_SIZE(lt8713sx->supplies), lt8713sx->supplies);
+}
+
+static struct i2c_device_id lt8713sx_id[] = {
+	{ "lontium,lt8713sx", 0 },
+	{ /* sentinel */ }
+};
+
+static const struct of_device_id lt8713sx_match_table[] = {
+	{ .compatible = "lontium,lt8713sx" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, lt8713sx_match_table);
+
+static struct i2c_driver lt8713sx_driver = {
+	.driver = {
+		.name = "lt8713sx",
+		.of_match_table = lt8713sx_match_table,
+		.dev_groups = lt8713sx_attr_groups,
+	},
+	.probe = lt8713sx_probe,
+	.remove = lt8713sx_remove,
+	.id_table = lt8713sx_id,
+};
+
+module_i2c_driver(lt8713sx_driver);
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("lt8713sx drm bridge driver");
+MODULE_AUTHOR("Tony <syyang@lontium.com>");
+MODULE_FIRMWARE(FW_FILE);

-- 
2.34.1

Re: [PATCH v2 2/2] drm/bridge: add support for lontium lt8713sx bridge driver

[Krzysztof Kozlowski]

On 18/11/2025 05:37, Vishnu Saini wrote:
> +static void lt8713sx_reset(struct lt8713sx *lt8713sx)
> +{
> +	pr_debug("reset bridge.\n");
> +	gpiod_set_value_cansleep(lt8713sx->reset_gpio, 1);
> +	msleep(20);
> +
> +	gpiod_set_value_cansleep(lt8713sx->reset_gpio, 0);
> +	msleep(20);
> +
> +	gpiod_set_value_cansleep(lt8713sx->reset_gpio, 1);
> +	msleep(20);
> +	pr_debug("reset done.\n");

No, it is not done, because you kept the device in the reset. 1 is
reset. Don't mix up line and logical signals.

> +}
> +
> +static int lt8713sx_regulator_init(struct lt8713sx *lt8713sx)
> +{
> +	int ret;
> +
> +	lt8713sx->supplies[0].supply = "vdd";
> +	lt8713sx->supplies[1].supply = "vcc";
> +
> +	ret = devm_regulator_bulk_get(lt8713sx->dev, 2, lt8713sx->supplies);
> +	if (ret < 0)
> +		return dev_err_probe(lt8713sx->dev, ret, "failed to get regulators\n");
> +
> +	ret = regulator_set_load(lt8713sx->supplies[0].consumer, 200000);
> +	if (ret < 0)
> +		return dev_err_probe(lt8713sx->dev, ret, "failed to set regulator load\n");
> +
> +	return 0;
> +}
> +
> +static int lt8713sx_regulator_enable(struct lt8713sx *lt8713sx)
> +{
> +	int ret;
> +
> +	ret = regulator_enable(lt8713sx->supplies[0].consumer);
> +	if (ret < 0)
> +		return dev_err_probe(lt8713sx->dev, ret, "failed to enable vdd regulator\n");
> +
> +	usleep_range(1000, 10000);
> +
> +	ret = regulator_enable(lt8713sx->supplies[1].consumer);
> +	if (ret < 0) {
> +		regulator_disable(lt8713sx->supplies[0].consumer);
> +		return dev_err_probe(lt8713sx->dev, ret, "failed to enable vcc regulator\n");
> +	}
> +	return 0;
> +}
> +
> +static int lt8713sx_gpio_init(struct lt8713sx *lt8713sx)
> +{
> +	struct device *dev = lt8713sx->dev;
> +
> +	lt8713sx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(lt8713sx->reset_gpio))
> +		return dev_err_probe(dev, PTR_ERR(lt8713sx->reset_gpio),
> +				     "failed to acquire reset gpio\n");
> +
> +	/* power enable gpio */
> +	lt8713sx->enable_gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_HIGH);
> +	if (IS_ERR(lt8713sx->enable_gpio))
> +		return dev_err_probe(dev, PTR_ERR(lt8713sx->enable_gpio),
> +				     "failed to acquire enable gpio\n");
> +	return 0;
> +}
> +
> +static ssize_t lt8713sx_firmware_store(struct device *dev,
> +				       struct device_attribute *attr,
> +				       const char *buf, size_t len)
> +{
> +	struct lt8713sx *lt8713sx = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = lt8713sx_firmware_update(lt8713sx);
> +	if (ret < 0)
> +		return ret;
> +	return len;
> +}
> +
> +static DEVICE_ATTR_WO(lt8713sx_firmware);
> +
> +static struct attribute *lt8713sx_attrs[] = {
> +	&dev_attr_lt8713sx_firmware.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group lt8713sx_attr_group = {
> +	.attrs = lt8713sx_attrs,
> +};
> +
> +static const struct attribute_group *lt8713sx_attr_groups[] = {
> +	&lt8713sx_attr_group,
> +	NULL,
> +};
> +
> +static int lt8713sx_probe(struct i2c_client *client)
> +{
> +	struct lt8713sx *lt8713sx;
> +	struct device *dev = &client->dev;
> +	int ret;
> +
> +	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
> +		return dev_err_probe(dev, -ENODEV, "device doesn't support I2C\n");
> +
> +	lt8713sx = devm_kzalloc(dev, sizeof(*lt8713sx), GFP_KERNEL);
> +	if (!lt8713sx)
> +		return dev_err_probe(dev, -ENOMEM, "failed to allocate lt8713sx struct\n");
> +
I did not ask for dev_err_probe here. Do you see such pattern anywhere?
No, because there are never error messages on memory allocation (see
coccinelle). Drop.

Please run standard kernel tools for static analysis, like coccinelle,
smatch and sparse, and fix reported warnings. Also please check for
warnings when building with W=1 for gcc and clang. Most of these
commands (checks or W=1 build) can build specific targets, like some
directory, to narrow the scope to only your code. The code here looks
like it needs a fix. Feel free to get in touch if the warning is not clear.

Best regards,
Krzysztof

Re: [PATCH v2 2/2] drm/bridge: add support for lontium lt8713sx bridge driver

[Vishnu Saini]

On Tue, Nov 18, 2025 at 08:37:22AM +0100, Krzysztof Kozlowski wrote:
> On 18/11/2025 05:37, Vishnu Saini wrote:
> > +static void lt8713sx_reset(struct lt8713sx *lt8713sx)
> > +{
> > +	pr_debug("reset bridge.\n");
> > +	gpiod_set_value_cansleep(lt8713sx->reset_gpio, 1);
> > +	msleep(20);
> > +
> > +	gpiod_set_value_cansleep(lt8713sx->reset_gpio, 0);
> > +	msleep(20);
> > +
> > +	gpiod_set_value_cansleep(lt8713sx->reset_gpio, 1);
> > +	msleep(20);
> > +	pr_debug("reset done.\n");
> 
> No, it is not done, because you kept the device in the reset. 1 is
> reset. Don't mix up line and logical signals.
done. 
> > +}
> > +
> > +static int lt8713sx_regulator_init(struct lt8713sx *lt8713sx)
> > +{
> > +	int ret;
> > +
> > +	lt8713sx->supplies[0].supply = "vdd";
> > +	lt8713sx->supplies[1].supply = "vcc";
> > +
> > +	ret = devm_regulator_bulk_get(lt8713sx->dev, 2, lt8713sx->supplies);
> > +	if (ret < 0)
> > +		return dev_err_probe(lt8713sx->dev, ret, "failed to get regulators\n");
> > +
> > +	ret = regulator_set_load(lt8713sx->supplies[0].consumer, 200000);
> > +	if (ret < 0)
> > +		return dev_err_probe(lt8713sx->dev, ret, "failed to set regulator load\n");
> > +
> > +	return 0;
> > +}
> > +
> > +static int lt8713sx_regulator_enable(struct lt8713sx *lt8713sx)
> > +{
> > +	int ret;
> > +
> > +	ret = regulator_enable(lt8713sx->supplies[0].consumer);
> > +	if (ret < 0)
> > +		return dev_err_probe(lt8713sx->dev, ret, "failed to enable vdd regulator\n");
> > +
> > +	usleep_range(1000, 10000);
> > +
> > +	ret = regulator_enable(lt8713sx->supplies[1].consumer);
> > +	if (ret < 0) {
> > +		regulator_disable(lt8713sx->supplies[0].consumer);
> > +		return dev_err_probe(lt8713sx->dev, ret, "failed to enable vcc regulator\n");
> > +	}
> > +	return 0;
> > +}
> > +
> > +static int lt8713sx_gpio_init(struct lt8713sx *lt8713sx)
> > +{
> > +	struct device *dev = lt8713sx->dev;
> > +
> > +	lt8713sx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> > +	if (IS_ERR(lt8713sx->reset_gpio))
> > +		return dev_err_probe(dev, PTR_ERR(lt8713sx->reset_gpio),
> > +				     "failed to acquire reset gpio\n");
> > +
> > +	/* power enable gpio */
> > +	lt8713sx->enable_gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_HIGH);
> > +	if (IS_ERR(lt8713sx->enable_gpio))
> > +		return dev_err_probe(dev, PTR_ERR(lt8713sx->enable_gpio),
> > +				     "failed to acquire enable gpio\n");
> > +	return 0;
> > +}
> > +
> > +static ssize_t lt8713sx_firmware_store(struct device *dev,
> > +				       struct device_attribute *attr,
> > +				       const char *buf, size_t len)
> > +{
> > +	struct lt8713sx *lt8713sx = dev_get_drvdata(dev);
> > +	int ret;
> > +
> > +	ret = lt8713sx_firmware_update(lt8713sx);
> > +	if (ret < 0)
> > +		return ret;
> > +	return len;
> > +}
> > +
> > +static DEVICE_ATTR_WO(lt8713sx_firmware);
> > +
> > +static struct attribute *lt8713sx_attrs[] = {
> > +	&dev_attr_lt8713sx_firmware.attr,
> > +	NULL,
> > +};
> > +
> > +static const struct attribute_group lt8713sx_attr_group = {
> > +	.attrs = lt8713sx_attrs,
> > +};
> > +
> > +static const struct attribute_group *lt8713sx_attr_groups[] = {
> > +	&lt8713sx_attr_group,
> > +	NULL,
> > +};
> > +
> > +static int lt8713sx_probe(struct i2c_client *client)
> > +{
> > +	struct lt8713sx *lt8713sx;
> > +	struct device *dev = &client->dev;
> > +	int ret;
> > +
> > +	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
> > +		return dev_err_probe(dev, -ENODEV, "device doesn't support I2C\n");
> > +
> > +	lt8713sx = devm_kzalloc(dev, sizeof(*lt8713sx), GFP_KERNEL);
> > +	if (!lt8713sx)
> > +		return dev_err_probe(dev, -ENOMEM, "failed to allocate lt8713sx struct\n");
> > +
> I did not ask for dev_err_probe here. Do you see such pattern anywhere?
> No, because there are never error messages on memory allocation (see
> coccinelle). Drop.
Dropped this dev_err_probe.
 
> Please run standard kernel tools for static analysis, like coccinelle,
> smatch and sparse, and fix reported warnings. Also please check for
> warnings when building with W=1 for gcc and clang. Most of these
> commands (checks or W=1 build) can build specific targets, like some
> directory, to narrow the scope to only your code. The code here looks
> like it needs a fix. Feel free to get in touch if the warning is not clear.

Run a couple of tools you mentioned and fixed the warnings in next patch.

> Best regards,
> Krzysztof

Re: [PATCH v2 2/2] drm/bridge: add support for lontium lt8713sx bridge driver

[Dmitry Baryshkov]

On Tue, Nov 18, 2025 at 10:07:09AM +0530, Vishnu Saini wrote:
> The lt8713sx is a Type-C/DP1.4 to Type-C/DP1.4/HDMI2.0 converter,
> with three configurable DP1.4/HDMI2.0/DP++ output interfaces and
> audio output interface.
> 
> Driver is required for firmware upgrade in the bridge chip.
> 
> Co-developed-by: Prahlad Valluru <vvalluru@qti.qualcomm.com>
> Signed-off-by: Prahlad Valluru <vvalluru@qti.qualcomm.com>
> Signed-off-by: Vishnu Saini <vishnu.saini@oss.qualcomm.com>
> ---
>  drivers/gpu/drm/bridge/Kconfig            |  10 ++
>  drivers/gpu/drm/bridge/Makefile           |   1 +
>  drivers/gpu/drm/bridge/lontium-lt8713sx.c | 713 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 724 insertions(+)
> 
> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> index a250afd8d662..7fef383ed7cb 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -184,6 +184,16 @@ config DRM_LONTIUM_LT9611UXC
>  	  HDMI signals
>  	  Please say Y if you have such hardware.
>  
> +config DRM_LONTIUM_LT8713SX
> +	tristate "Lontium LT8713SX DP MST bridge"
> +	depends on OF
> +	select REGMAP_I2C
> +	help
> +	  Driver for Lontium LT8713SX DP MST bridge
> +	  chip firmware upgrade, which converts Type-C/DP1.4
> +	  to 3 configurable Type-C/DP1.4/HDMI2.0 outputs
> +	  Please say Y if you have such hardware.
> +
>  config DRM_ITE_IT66121
>  	tristate "ITE IT66121 HDMI bridge"
>  	depends on OF
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index c7dc03182e59..07eeb13fa497 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -16,6 +16,7 @@ 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_LT9611UXC) += lontium-lt9611uxc.o
> +obj-$(CONFIG_DRM_LONTIUM_LT8713SX) += lontium-lt8713sx.o
>  obj-$(CONFIG_DRM_LVDS_CODEC) += lvds-codec.o
>  obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.o
>  obj-$(CONFIG_DRM_MICROCHIP_LVDS_SERIALIZER) += microchip-lvds.o
> diff --git a/drivers/gpu/drm/bridge/lontium-lt8713sx.c b/drivers/gpu/drm/bridge/lontium-lt8713sx.c
> new file mode 100644
> index 000000000000..a5aed2474a2e
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/lontium-lt8713sx.c
> @@ -0,0 +1,713 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> + */
> +
> +#include <linux/firmware.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/interrupt.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 <linux/wait.h>
> +#include <linux/workqueue.h>
> +
> +#define FW_FILE "lt8713sx_fw.bin"

Is it going to be submitted to linux-firmware? If not, why?

> +
> +#define LT8713SX_PAGE_SIZE 256
> +#define FW_12K_SIZE        (12  * 1024)
> +#define FW_64K_SIZE        (64  * 1024)
> +#define FW_256K_SIZE       (256 * 1024)

See <linux/sizes.h> and drop these defines.

> +
> +struct crc_config {
> +	u8 width;
> +	u32 poly;
> +	u32 crc_init;
> +	u32 xor_out;
> +	bool ref_in;
> +	bool ref_out;
> +};
> +
> +struct lt8713sx {
> +	struct device *dev;
> +
> +	struct regmap *regmap;
> +	/* Protects all accesses to registers by stopping the on-chip MCU */
> +	struct mutex ocm_lock;
> +
> +	struct gpio_desc *reset_gpio;
> +	struct gpio_desc *enable_gpio;
> +
> +	struct regulator_bulk_data supplies[2];
> +
> +	struct i2c_client *client;
> +	const struct firmware *fw;
> +
> +	u8 *fw_buffer;
> +
> +	u32 main_crc_value;
> +	u32 bank_crc_value[17];
> +
> +	int bank_num;
> +};
> +
> +static void lt8713sx_reset(struct lt8713sx *lt8713sx);
> +
> +static const struct regmap_range lt8713sx_ranges[] = {
> +	{
> +		.range_min = 0,
> +		.range_max = 0xffff
> +	},
> +};
> +
> +static const struct regmap_access_table lt8713sx_table = {
> +	.yes_ranges = lt8713sx_ranges,
> +	.n_yes_ranges = ARRAY_SIZE(lt8713sx_ranges),
> +};
> +
> +static const struct regmap_config lt8713sx_regmap_config = {
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.volatile_table = &lt8713sx_table,
> +	.cache_type = REGCACHE_NONE,
> +};
> +
> +static void lt8713sx_i2c_enable(struct lt8713sx *lt8713sx)
> +{
> +	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
> +	regmap_write(lt8713sx->regmap, 0xee, 0x01);

Is 0xff page-swapping register? If so, please declare it so and use
16-bit addressing (see other Lontium drivers as an example).

> +}
> +
> +static void lt8713sx_i2c_disable(struct lt8713sx *lt8713sx)
> +{
> +	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
> +	regmap_write(lt8713sx->regmap, 0xee, 0x00);
> +}
> +
> +static unsigned int bits_reverse(u32 in_val, u8 bits)
> +{
> +	u32 out_val = 0;
> +	u8 i;
> +
> +	for (i = 0; i < bits; i++) {
> +		if (in_val & (1 << i))
> +			out_val |= 1 << (bits - 1 - i);
> +	}
> +
> +	return out_val;
> +}
> +
> +static unsigned int get_crc(struct crc_config crc_cfg, const  u8 *buf, u64 buf_len)
> +{
> +	u8 width    = crc_cfg.width;
> +	u32  poly   = crc_cfg.poly;
> +	u32  crc    = crc_cfg.crc_init;
> +	u32  xorout = crc_cfg.xor_out;
> +	bool refin  = crc_cfg.ref_in;
> +	bool refout = crc_cfg.ref_out;
> +	u8 n;
> +	u32  bits;
> +	u32  data;
> +	u8 i;
> +
> +	n    =  (width < 8) ? 0 : (width - 8);
> +	crc  =  (width < 8) ? (crc << (8 - width)) : crc;
> +	bits =  (width < 8) ? 0x80 : (1 << (width - 1));
> +	poly =  (width < 8) ? (poly << (8 - width)) : poly;
> +
> +	while (buf_len--) {
> +		data = *(buf++);
> +		if (refin)
> +			data = bits_reverse(data, 8);
> +		crc ^= (data << n);
> +		for (i = 0; i < 8; i++) {
> +			if (crc & bits)
> +				crc = (crc << 1) ^ poly;
> +			else
> +				crc = crc << 1;
> +		}
> +	}
> +	crc = (width < 8) ? (crc >> (8 - width)) : crc;
> +	if (refout)
> +		crc = bits_reverse(crc, width);
> +	crc ^= xorout;
> +
> +	return (crc & ((2 << (width - 1)) - 1));
> +}

NAK for the manual CRC calculation. Use <linux/crc8.h>

> +
> +static u32 calculate_64K_crc(const u8 *upgrade_data, u64 len)
> +{
> +	struct crc_config crc_cfg = {
> +		.width = 8,
> +		.poly  = 0x31,
> +		.crc_init = 0,
> +		.xor_out = 0,
> +		.ref_out = false,
> +		.ref_in = false,
> +	};
> +	u64 crc_size = FW_64K_SIZE - 1;
> +	u8 default_val = 0xFF;

Please use consistent style, It's recommended to use lower case hex.

> +
> +	crc_cfg.crc_init = get_crc(crc_cfg, upgrade_data, len);
> +
> +	crc_size -= len;
> +	while (crc_size--)
> +		crc_cfg.crc_init = get_crc(crc_cfg, &default_val, 1);
> +
> +	return crc_cfg.crc_init;
> +}
> +
> +static u32 calculate_12K_crc(const u8 *upgrade_data, u64 len)
> +{
> +	struct crc_config crc_cfg = {
> +		.width = 8,
> +		.poly  = 0x31,
> +		.crc_init = 0,
> +		.xor_out = 0,
> +		.ref_out = false,
> +		.ref_in = false,
> +	};
> +	u64 crc_size = FW_12K_SIZE;
> +	u8 default_val = 0xFF;
> +
> +	crc_cfg.crc_init = get_crc(crc_cfg, upgrade_data, len);
> +
> +	crc_size -= len;
> +	while (crc_size--)
> +		crc_cfg.crc_init = get_crc(crc_cfg, &default_val, 1);
> +
> +	return crc_cfg.crc_init;
> +}

The only difference from the previous function is the crc_size. Merge
them.

> +
> +static int lt8713sx_prepare_firmware_data(struct lt8713sx *lt8713sx)
> +{
> +	int ret = 0;
> +
> +	ret = request_firmware(&lt8713sx->fw, FW_FILE, lt8713sx->dev);
> +	if (ret < 0) {
> +		pr_err("request firmware failed\n");
> +		return ret;
> +	}
> +
> +	pr_debug("Firmware size: %zu bytes\n", lt8713sx->fw->size);
> +
> +	if (lt8713sx->fw->size > FW_256K_SIZE - 1) {
> +		pr_err("Firmware size exceeds 256KB limit\n");
> +		release_firmware(lt8713sx->fw);
> +		return -EINVAL;
> +	}
> +
> +	lt8713sx->fw_buffer = kzalloc(FW_256K_SIZE, GFP_KERNEL);

I think 256k is already big enough to be used for vmalloc instead. Also,
there is no need to zero-fill it, if you are going to fill it with 0xff
in the next line.

> +	if (!lt8713sx->fw_buffer) {
> +		release_firmware(lt8713sx->fw);
> +		return -ENOMEM;
> +	}
> +
> +	memset(lt8713sx->fw_buffer, 0xFF, FW_256K_SIZE);
> +
> +	if (lt8713sx->fw->size < FW_64K_SIZE) {
> +		/*TODO: CRC should be calculated with 0xff also */

Is this still relevant?

> +		memcpy(lt8713sx->fw_buffer, lt8713sx->fw->data, lt8713sx->fw->size);
> +		lt8713sx->fw_buffer[FW_64K_SIZE - 1] =
> +				calculate_64K_crc(lt8713sx->fw->data, lt8713sx->fw->size);

You have already put your firmware into 0xff-filled 256k buffer. It's
safe to pass SZ_64K here. Then you can drop the 'tail' CRC calculation
from calculate_64K_crc() and calculate_12K_crc().

> +		lt8713sx->main_crc_value = lt8713sx->fw_buffer[FW_64K_SIZE - 1];
> +		pr_debug("Main Firmware Data  Crc=0x%02X\n", lt8713sx->main_crc_value);
> +
> +	} else {
> +		//main firmware
> +		memcpy(lt8713sx->fw_buffer, lt8713sx->fw->data, FW_64K_SIZE - 1);
> +		lt8713sx->fw_buffer[FW_64K_SIZE - 1] =
> +				calculate_64K_crc(lt8713sx->fw_buffer, FW_64K_SIZE - 1);
> +		lt8713sx->main_crc_value = lt8713sx->fw_buffer[FW_64K_SIZE - 1];
> +		pr_debug("Main Firmware Data  Crc=0x%02X\n", lt8713sx->main_crc_value);
> +
> +		//bank firmware
> +		memcpy(lt8713sx->fw_buffer + FW_64K_SIZE,
> +		       lt8713sx->fw->data + FW_64K_SIZE,
> +		       lt8713sx->fw->size - FW_64K_SIZE);
> +
> +		lt8713sx->bank_num = (lt8713sx->fw->size - FW_64K_SIZE + FW_12K_SIZE - 1) /
> +					FW_12K_SIZE;
> +		pr_debug("Bank Number Total is %d.\n", lt8713sx->bank_num);
> +
> +		for (int i = 0; i < lt8713sx->bank_num; i++) {
> +			lt8713sx->bank_crc_value[i] =
> +				calculate_12K_crc(lt8713sx->fw_buffer + FW_64K_SIZE +
> +						  i * FW_12K_SIZE,
> +						  FW_12K_SIZE);
> +			pr_debug("Bank number:%d; Firmware Data  Crc:0x%02X\n",
> +				 i, lt8713sx->bank_crc_value[i]);
> +		}
> +	}
> +	return 0;
> +}
> +
> +static void lt8713sx_config_parameters(struct lt8713sx *lt8713sx)
> +{
> +	regmap_write(lt8713sx->regmap, 0xFF, 0xE0);
> +	regmap_write(lt8713sx->regmap, 0xEE, 0x01);
> +	regmap_write(lt8713sx->regmap, 0x5E, 0xC1);
> +	regmap_write(lt8713sx->regmap, 0x58, 0x00);
> +	regmap_write(lt8713sx->regmap, 0x59, 0x50);
> +	regmap_write(lt8713sx->regmap, 0x5A, 0x10);
> +	regmap_write(lt8713sx->regmap, 0x5A, 0x00);
> +	regmap_write(lt8713sx->regmap, 0x58, 0x21);
> +}
> +
> +static void lt8713sx_wren(struct lt8713sx *lt8713sx)
> +{
> +	regmap_write(lt8713sx->regmap, 0xff, 0xe1);
> +	regmap_write(lt8713sx->regmap, 0x03, 0xbf);
> +	regmap_write(lt8713sx->regmap, 0x03, 0xff);
> +	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
> +	regmap_write(lt8713sx->regmap, 0x5a, 0x04);
> +	regmap_write(lt8713sx->regmap, 0x5a, 0x00);
> +}
> +
> +static void lt8713sx_wrdi(struct lt8713sx *lt8713sx)
> +{
> +	regmap_write(lt8713sx->regmap, 0x5A, 0x08);
> +	regmap_write(lt8713sx->regmap, 0x5A, 0x00);
> +}
> +
> +static void lt8713sx_fifo_reset(struct lt8713sx *lt8713sx)
> +{
> +	regmap_write(lt8713sx->regmap, 0xff, 0xe1);
> +	regmap_write(lt8713sx->regmap, 0x03, 0xbf);
> +	regmap_write(lt8713sx->regmap, 0x03, 0xff);
> +}
> +
> +static void lt8713sx_disable_sram_write(struct lt8713sx *lt8713sx)
> +{
> +	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
> +	regmap_write(lt8713sx->regmap, 0x55, 0x00);
> +}
> +
> +static void lt8713sx_sram_to_flash(struct lt8713sx *lt8713sx)
> +{
> +	regmap_write(lt8713sx->regmap, 0x5a, 0x30);
> +	regmap_write(lt8713sx->regmap, 0x5a, 0x00);
> +}
> +
> +static void lt8713sx_i2c_to_sram(struct lt8713sx *lt8713sx)
> +{
> +	regmap_write(lt8713sx->regmap, 0x55, 0x80);
> +	regmap_write(lt8713sx->regmap, 0x5e, 0xc0);
> +	regmap_write(lt8713sx->regmap, 0x58, 0x21);
> +}
> +
> +static u8 lt8713sx_read_flash_status(struct lt8713sx *lt8713sx)
> +{
> +	u32 flash_status = 0;
> +
> +	regmap_write(lt8713sx->regmap,  0xFF, 0xE1);//fifo_rst_n
> +	regmap_write(lt8713sx->regmap,  0x03, 0x3F);
> +	regmap_write(lt8713sx->regmap,  0x03, 0xFF);
> +
> +	regmap_write(lt8713sx->regmap,  0xFF, 0xE0);
> +	regmap_write(lt8713sx->regmap,  0x5e, 0x40);
> +	regmap_write(lt8713sx->regmap,  0x56, 0x05);//opcode=read status register
> +	regmap_write(lt8713sx->regmap,  0x55, 0x25);
> +	regmap_write(lt8713sx->regmap,  0x55, 0x01);
> +	regmap_write(lt8713sx->regmap,  0x58, 0x21);
> +
> +	regmap_read(lt8713sx->regmap, 0x5f, &flash_status);
> +	pr_debug("flash_status:%x\n", flash_status);
> +
> +	return flash_status;
> +}
> +
> +static void lt8713sx_block_erase(struct lt8713sx *lt8713sx)
> +{
> +	u32 i = 0;
> +	u8 flash_status = 0;
> +	u8 blocknum = 0x00;
> +	u32 flashaddr = 0x00;
> +
> +	for (blocknum = 0; blocknum < 8; blocknum++) {
> +		flashaddr = blocknum * 0x008000;

SZ_32K

> +		regmap_write(lt8713sx->regmap,  0xFF, 0xE0);
> +		regmap_write(lt8713sx->regmap,  0xEE, 0x01);
> +		regmap_write(lt8713sx->regmap,  0x5A, 0x04);
> +		regmap_write(lt8713sx->regmap,  0x5A, 0x00);
> +		regmap_write(lt8713sx->regmap,  0x5B, flashaddr >> 16);//set flash address[23:16]
> +		regmap_write(lt8713sx->regmap,  0x5C, flashaddr >> 8);//set flash address[15:8]
> +		regmap_write(lt8713sx->regmap,  0x5D, flashaddr);//set flash address[7:0]
> +		regmap_write(lt8713sx->regmap,  0x5A, 0x01);
> +		regmap_write(lt8713sx->regmap,  0x5A, 0x00);
> +		msleep(100); //delay 100ms

Please drop useless comments. It's clear that msleep delays for 100ms.

> +		i = 0;
> +		while (1) {
> +			flash_status = lt8713sx_read_flash_status(lt8713sx); //wait erase finish
> +			if ((flash_status & 0x01) == 0)
> +				break;
> +
> +			if (i > 50)
> +				break;
> +
> +			i++;
> +			msleep(50); //delay 50ms
> +		}
> +	}
> +	pr_debug("erase flash done.\n");
> +}
> +
> +static void lt8713sx_load_main_fw_to_sram(struct lt8713sx *lt8713sx)
> +{
> +	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
> +	regmap_write(lt8713sx->regmap, 0xee, 0x01);
> +	regmap_write(lt8713sx->regmap, 0x68, 0x00);
> +	regmap_write(lt8713sx->regmap, 0x69, 0x00);
> +	regmap_write(lt8713sx->regmap, 0x6a, 0x00);
> +	regmap_write(lt8713sx->regmap, 0x65, 0x00);
> +	regmap_write(lt8713sx->regmap, 0x66, 0xff);
> +	regmap_write(lt8713sx->regmap, 0x67, 0xff);
> +	regmap_write(lt8713sx->regmap, 0x6b, 0x00);
> +	regmap_write(lt8713sx->regmap, 0x6c, 0x00);
> +	regmap_write(lt8713sx->regmap, 0x60, 0x01);
> +	msleep(200);
> +	regmap_write(lt8713sx->regmap, 0x60, 0x00);
> +}
> +
> +static void lt8713sx_load_bank_fw_to_sram(struct lt8713sx *lt8713sx, u64 addr)
> +{
> +	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
> +	regmap_write(lt8713sx->regmap, 0xee, 0x01);
> +	regmap_write(lt8713sx->regmap, 0x68, ((addr & 0xFF0000) >> 16));
> +	regmap_write(lt8713sx->regmap, 0x69, ((addr & 0x00FF00) >> 8));
> +	regmap_write(lt8713sx->regmap, 0x6a, (addr & 0x0000FF));
> +	regmap_write(lt8713sx->regmap, 0x65, 0x00);
> +	regmap_write(lt8713sx->regmap, 0x66, 0x30);
> +	regmap_write(lt8713sx->regmap, 0x67, 0x00);
> +	regmap_write(lt8713sx->regmap, 0x6b, 0x00);
> +	regmap_write(lt8713sx->regmap, 0x6c, 0x00);
> +	regmap_write(lt8713sx->regmap, 0x60, 0x01);
> +	msleep(50);
> +	regmap_write(lt8713sx->regmap, 0x60, 0x00);
> +}
> +
> +static int lt8713sx_write_data(struct lt8713sx *lt8713sx, const u8 *data, u64 filesize)
> +{
> +	int page = 0, num = 0, i = 0, val;
> +
> +	page = (filesize % LT8713SX_PAGE_SIZE) ?
> +			((filesize / LT8713SX_PAGE_SIZE) + 1) : (filesize / LT8713SX_PAGE_SIZE);
> +
> +	pr_debug("Writing to Sram=%u pages, total size = %llu bytes\n", page, filesize);
> +
> +	for (num = 0; num < page; num++) {
> +		pr_debug("page[%d]\n", num);
> +		lt8713sx_i2c_to_sram(lt8713sx);
> +
> +		for (i = 0; i < LT8713SX_PAGE_SIZE; i++) {
> +			if ((num * LT8713SX_PAGE_SIZE + i) < filesize)
> +				val = *(data + (num * LT8713SX_PAGE_SIZE + i));
> +			else
> +				val = 0xFF;
> +			regmap_write(lt8713sx->regmap, 0x59, val);
> +		}
> +
> +		lt8713sx_wren(lt8713sx);
> +		lt8713sx_sram_to_flash(lt8713sx);
> +	}
> +
> +	lt8713sx_wrdi(lt8713sx);
> +	lt8713sx_disable_sram_write(lt8713sx);
> +
> +	return 0;
> +}
> +
> +static void lt8713sx_main_upgrade_result(struct lt8713sx *lt8713sx)
> +{
> +	u32 main_crc_result;
> +
> +	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
> +	regmap_read(lt8713sx->regmap, 0x23, &main_crc_result);
> +
> +	pr_debug("Main CRC HW: 0x%02X\n", main_crc_result);
> +	pr_debug("Main CRC FW: 0x%02X\n", lt8713sx->main_crc_value);
> +
> +	if (main_crc_result == lt8713sx->main_crc_value)
> +		pr_debug("Main Firmware Upgrade Success.\n");
> +	else
> +		pr_err("Main Firmware Upgrade Failed.\n");
> +}
> +
> +static void lt8713sx_bank_upgrade_result(struct lt8713sx *lt8713sx, u8 banknum)
> +{
> +	u32 bank_crc_result;
> +
> +	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
> +
> +	regmap_read(lt8713sx->regmap, 0x23, &bank_crc_result);
> +
> +	pr_debug("Bank %d CRC Result: 0x%02X\n", banknum, bank_crc_result);
> +
> +	if (bank_crc_result == lt8713sx->bank_crc_value[banknum])
> +		pr_debug("Bank %d Firmware Upgrade Success.\n", banknum);
> +	else
> +		pr_err("Bank %d Firmware Upgrade Failed.\n", banknum);
> +}
> +
> +static void lt8713sx_bank_result_check(struct lt8713sx *lt8713sx)
> +{
> +	int i;
> +	u64 addr = 0x010000;
> +
> +	for (i = 0; i < lt8713sx->bank_num; i++) {
> +		lt8713sx_load_bank_fw_to_sram(lt8713sx, addr);
> +		lt8713sx_bank_upgrade_result(lt8713sx, i);
> +		addr += 0x3000;
> +	}
> +}
> +
> +static int lt8713sx_firmware_upgrade(struct lt8713sx *lt8713sx)
> +{
> +	int ret;
> +
> +	lt8713sx_config_parameters(lt8713sx);
> +
> +	lt8713sx_block_erase(lt8713sx);
> +
> +	if (lt8713sx->fw->size < FW_64K_SIZE) {
> +		ret = lt8713sx_write_data(lt8713sx, lt8713sx->fw_buffer, FW_64K_SIZE);
> +		if (ret < 0) {
> +			pr_err("Failed to write firmware data: %d\n", ret);
> +			return ret;
> +		}
> +	} else {
> +		ret = lt8713sx_write_data(lt8713sx, lt8713sx->fw_buffer, lt8713sx->fw->size);
> +		if (ret < 0) {
> +			pr_err("Failed to write firmware data: %d\n", ret);
> +			return ret;
> +		}
> +	}
> +
> +	pr_debug("Write Data done.\n");
> +
> +	return 0;
> +}
> +
> +static int lt8713sx_firmware_update(struct lt8713sx *lt8713sx)
> +{
> +	int ret = 0;
> +
> +	mutex_lock(&lt8713sx->ocm_lock);
> +	lt8713sx_i2c_enable(lt8713sx);
> +
> +	ret = lt8713sx_prepare_firmware_data(lt8713sx);
> +	if (ret < 0) {
> +		pr_err("Failed to prepare firmware data: %d\n", ret);
> +		goto error;
> +	}
> +
> +	ret = lt8713sx_firmware_upgrade(lt8713sx);
> +	if (ret < 0) {
> +		pr_err("Upgrade failure.\n");
> +		goto error;
> +	} else {
> +		/* Validate CRC */
> +		lt8713sx_load_main_fw_to_sram(lt8713sx);
> +		lt8713sx_main_upgrade_result(lt8713sx);
> +		lt8713sx_wrdi(lt8713sx);
> +		lt8713sx_fifo_reset(lt8713sx);
> +		lt8713sx_bank_result_check(lt8713sx);
> +		lt8713sx_wrdi(lt8713sx);
> +	}
> +
> +error:
> +	lt8713sx_i2c_disable(lt8713sx);
> +	if (!ret)
> +		lt8713sx_reset(lt8713sx);
> +
> +	kfree(lt8713sx->fw_buffer);
> +	lt8713sx->fw_buffer = NULL;
> +
> +	if (lt8713sx->fw) {
> +		release_firmware(lt8713sx->fw);
> +		lt8713sx->fw = NULL;
> +	}
> +	mutex_unlock(&lt8713sx->ocm_lock);
> +
> +	return ret;
> +}
> +
> +static void lt8713sx_reset(struct lt8713sx *lt8713sx)
> +{
> +	pr_debug("reset bridge.\n");
> +	gpiod_set_value_cansleep(lt8713sx->reset_gpio, 1);
> +	msleep(20);
> +
> +	gpiod_set_value_cansleep(lt8713sx->reset_gpio, 0);
> +	msleep(20);
> +
> +	gpiod_set_value_cansleep(lt8713sx->reset_gpio, 1);
> +	msleep(20);
> +	pr_debug("reset done.\n");
> +}
> +
> +static int lt8713sx_regulator_init(struct lt8713sx *lt8713sx)
> +{
> +	int ret;
> +
> +	lt8713sx->supplies[0].supply = "vdd";
> +	lt8713sx->supplies[1].supply = "vcc";
> +
> +	ret = devm_regulator_bulk_get(lt8713sx->dev, 2, lt8713sx->supplies);
> +	if (ret < 0)
> +		return dev_err_probe(lt8713sx->dev, ret, "failed to get regulators\n");
> +
> +	ret = regulator_set_load(lt8713sx->supplies[0].consumer, 200000);
> +	if (ret < 0)
> +		return dev_err_probe(lt8713sx->dev, ret, "failed to set regulator load\n");
> +
> +	return 0;
> +}
> +
> +static int lt8713sx_regulator_enable(struct lt8713sx *lt8713sx)
> +{
> +	int ret;
> +
> +	ret = regulator_enable(lt8713sx->supplies[0].consumer);
> +	if (ret < 0)
> +		return dev_err_probe(lt8713sx->dev, ret, "failed to enable vdd regulator\n");
> +
> +	usleep_range(1000, 10000);
> +
> +	ret = regulator_enable(lt8713sx->supplies[1].consumer);
> +	if (ret < 0) {
> +		regulator_disable(lt8713sx->supplies[0].consumer);
> +		return dev_err_probe(lt8713sx->dev, ret, "failed to enable vcc regulator\n");
> +	}
> +	return 0;
> +}
> +
> +static int lt8713sx_gpio_init(struct lt8713sx *lt8713sx)
> +{
> +	struct device *dev = lt8713sx->dev;
> +
> +	lt8713sx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(lt8713sx->reset_gpio))
> +		return dev_err_probe(dev, PTR_ERR(lt8713sx->reset_gpio),
> +				     "failed to acquire reset gpio\n");
> +
> +	/* power enable gpio */
> +	lt8713sx->enable_gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_HIGH);
> +	if (IS_ERR(lt8713sx->enable_gpio))
> +		return dev_err_probe(dev, PTR_ERR(lt8713sx->enable_gpio),
> +				     "failed to acquire enable gpio\n");
> +	return 0;
> +}
> +
> +static ssize_t lt8713sx_firmware_store(struct device *dev,
> +				       struct device_attribute *attr,
> +				       const char *buf, size_t len)
> +{
> +	struct lt8713sx *lt8713sx = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = lt8713sx_firmware_update(lt8713sx);
> +	if (ret < 0)
> +		return ret;
> +	return len;
> +}
> +
> +static DEVICE_ATTR_WO(lt8713sx_firmware);
> +
> +static struct attribute *lt8713sx_attrs[] = {
> +	&dev_attr_lt8713sx_firmware.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group lt8713sx_attr_group = {
> +	.attrs = lt8713sx_attrs,
> +};
> +
> +static const struct attribute_group *lt8713sx_attr_groups[] = {
> +	&lt8713sx_attr_group,
> +	NULL,
> +};
> +
> +static int lt8713sx_probe(struct i2c_client *client)
> +{
> +	struct lt8713sx *lt8713sx;
> +	struct device *dev = &client->dev;
> +	int ret;
> +
> +	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
> +		return dev_err_probe(dev, -ENODEV, "device doesn't support I2C\n");
> +
> +	lt8713sx = devm_kzalloc(dev, sizeof(*lt8713sx), GFP_KERNEL);
> +	if (!lt8713sx)
> +		return dev_err_probe(dev, -ENOMEM, "failed to allocate lt8713sx struct\n");
> +
> +	lt8713sx->dev = dev;
> +	lt8713sx->client = client;
> +	i2c_set_clientdata(client, lt8713sx);
> +
> +	mutex_init(&lt8713sx->ocm_lock);

devm_mutex_init().

> +
> +	lt8713sx->regmap = devm_regmap_init_i2c(client, &lt8713sx_regmap_config);
> +	if (IS_ERR(lt8713sx->regmap))
> +		return dev_err_probe(dev, PTR_ERR(lt8713sx->regmap), "regmap i2c init failed\n");
> +
> +	ret = lt8713sx_gpio_init(lt8713sx);
> +	if (ret < 0)
> +		goto err_of_put;

err_of_put is just a return. Please inline it.

> +
> +	ret = lt8713sx_regulator_init(lt8713sx);
> +	if (ret < 0)
> +		goto err_of_put;
> +
> +	ret = lt8713sx_regulator_enable(lt8713sx);
> +	if (ret)
> +		goto err_of_put;
> +
> +	lt8713sx_reset(lt8713sx);
> +
> +	return 0;
> +
> +err_of_put:
> +	return ret;
> +}
> +
> +static void lt8713sx_remove(struct i2c_client *client)
> +{
> +	struct lt8713sx *lt8713sx = i2c_get_clientdata(client);
> +
> +	mutex_destroy(&lt8713sx->ocm_lock);
> +
> +	regulator_bulk_disable(ARRAY_SIZE(lt8713sx->supplies), lt8713sx->supplies);

Use devm_regulator_get_enable(), then you can drop this line.

> +}
> +
> +static struct i2c_device_id lt8713sx_id[] = {
> +	{ "lontium,lt8713sx", 0 },
> +	{ /* sentinel */ }
> +};
> +
> +static const struct of_device_id lt8713sx_match_table[] = {
> +	{ .compatible = "lontium,lt8713sx" },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, lt8713sx_match_table);
> +
> +static struct i2c_driver lt8713sx_driver = {
> +	.driver = {
> +		.name = "lt8713sx",
> +		.of_match_table = lt8713sx_match_table,
> +		.dev_groups = lt8713sx_attr_groups,
> +	},
> +	.probe = lt8713sx_probe,
> +	.remove = lt8713sx_remove,
> +	.id_table = lt8713sx_id,
> +};
> +
> +module_i2c_driver(lt8713sx_driver);
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("lt8713sx drm bridge driver");
> +MODULE_AUTHOR("Tony <syyang@lontium.com>");
> +MODULE_FIRMWARE(FW_FILE);
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry

Re: [PATCH v2 2/2] drm/bridge: add support for lontium lt8713sx bridge driver

[Vishnu Saini]

On Fri, Nov 20, 2025 at 02:55:07PM +0200, Dmitry Baryshkov wrote:
> On Tue, Nov 18, 2025 at 10:07:09AM +0530, Vishnu Saini wrote:
> > The lt8713sx is a Type-C/DP1.4 to Type-C/DP1.4/HDMI2.0 converter,
> > with three configurable DP1.4/HDMI2.0/DP++ output interfaces and
> > audio output interface.
> > 
> > Driver is required for firmware upgrade in the bridge chip.
> > 
> > Co-developed-by: Prahlad Valluru <vvalluru@qti.qualcomm.com>
> > Signed-off-by: Prahlad Valluru <vvalluru@qti.qualcomm.com>
> > Signed-off-by: Vishnu Saini <vishnu.saini@oss.qualcomm.com>
> > ---
> >  drivers/gpu/drm/bridge/Kconfig            |  10 ++
> >  drivers/gpu/drm/bridge/Makefile           |   1 +
> >  drivers/gpu/drm/bridge/lontium-lt8713sx.c | 713 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 724 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> > index a250afd8d662..7fef383ed7cb 100644
> > --- a/drivers/gpu/drm/bridge/Kconfig
> > +++ b/drivers/gpu/drm/bridge/Kconfig
> > @@ -184,6 +184,16 @@ config DRM_LONTIUM_LT9611UXC
> >  	  HDMI signals
> >  	  Please say Y if you have such hardware.
> >  
> > +config DRM_LONTIUM_LT8713SX
> > +	tristate "Lontium LT8713SX DP MST bridge"
> > +	depends on OF
> > +	select REGMAP_I2C
> > +	help
> > +	  Driver for Lontium LT8713SX DP MST bridge
> > +	  chip firmware upgrade, which converts Type-C/DP1.4
> > +	  to 3 configurable Type-C/DP1.4/HDMI2.0 outputs
> > +	  Please say Y if you have such hardware.
> > +
> >  config DRM_ITE_IT66121
> >  	tristate "ITE IT66121 HDMI bridge"
> >  	depends on OF
> > diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> > index c7dc03182e59..07eeb13fa497 100644
> > --- a/drivers/gpu/drm/bridge/Makefile
> > +++ b/drivers/gpu/drm/bridge/Makefile
> > @@ -16,6 +16,7 @@ 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_LT9611UXC) += lontium-lt9611uxc.o
> > +obj-$(CONFIG_DRM_LONTIUM_LT8713SX) += lontium-lt8713sx.o
> >  obj-$(CONFIG_DRM_LVDS_CODEC) += lvds-codec.o
> >  obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.o
> >  obj-$(CONFIG_DRM_MICROCHIP_LVDS_SERIALIZER) += microchip-lvds.o
> > diff --git a/drivers/gpu/drm/bridge/lontium-lt8713sx.c b/drivers/gpu/drm/bridge/lontium-lt8713sx.c
> > new file mode 100644
> > index 000000000000..a5aed2474a2e
> > --- /dev/null
> > +++ b/drivers/gpu/drm/bridge/lontium-lt8713sx.c
> > @@ -0,0 +1,713 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> > + */
> > +
> > +#include <linux/firmware.h>
> > +#include <linux/gpio/consumer.h>
> > +#include <linux/i2c.h>
> > +#include <linux/interrupt.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 <linux/wait.h>
> > +#include <linux/workqueue.h>
> > +
> > +#define FW_FILE "lt8713sx_fw.bin"
> 
> Is it going to be submitted to linux-firmware? If not, why?
Yes, if needed will submit. 
> > +
> > +#define LT8713SX_PAGE_SIZE 256
> > +#define FW_12K_SIZE        (12  * 1024)
> > +#define FW_64K_SIZE        (64  * 1024)
> > +#define FW_256K_SIZE       (256 * 1024)
> 
> See <linux/sizes.h> and drop these defines.
done. 
> > +
> > +struct crc_config {
> > +	u8 width;
> > +	u32 poly;
> > +	u32 crc_init;
> > +	u32 xor_out;
> > +	bool ref_in;
> > +	bool ref_out;
> > +};
> > +
> > +struct lt8713sx {
> > +	struct device *dev;
> > +
> > +	struct regmap *regmap;
> > +	/* Protects all accesses to registers by stopping the on-chip MCU */
> > +	struct mutex ocm_lock;
> > +
> > +	struct gpio_desc *reset_gpio;
> > +	struct gpio_desc *enable_gpio;
> > +
> > +	struct regulator_bulk_data supplies[2];
> > +
> > +	struct i2c_client *client;
> > +	const struct firmware *fw;
> > +
> > +	u8 *fw_buffer;
> > +
> > +	u32 main_crc_value;
> > +	u32 bank_crc_value[17];
> > +
> > +	int bank_num;
> > +};
> > +
> > +static void lt8713sx_reset(struct lt8713sx *lt8713sx);
> > +
> > +static const struct regmap_range lt8713sx_ranges[] = {
> > +	{
> > +		.range_min = 0,
> > +		.range_max = 0xffff
> > +	},
> > +};
> > +
> > +static const struct regmap_access_table lt8713sx_table = {
> > +	.yes_ranges = lt8713sx_ranges,
> > +	.n_yes_ranges = ARRAY_SIZE(lt8713sx_ranges),
> > +};
> > +
> > +static const struct regmap_config lt8713sx_regmap_config = {
> > +	.reg_bits = 8,
> > +	.val_bits = 8,
> > +	.volatile_table = &lt8713sx_table,
> > +	.cache_type = REGCACHE_NONE,
> > +};
> > +
> > +static void lt8713sx_i2c_enable(struct lt8713sx *lt8713sx)
> > +{
> > +	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
> > +	regmap_write(lt8713sx->regmap, 0xee, 0x01);
> 
> Is 0xff page-swapping register? If so, please declare it so and use
> 16-bit addressing (see other Lontium drivers as an example).
done. 
> > +}
> > +
> > +static void lt8713sx_i2c_disable(struct lt8713sx *lt8713sx)
> > +{
> > +	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
> > +	regmap_write(lt8713sx->regmap, 0xee, 0x00);
> > +}
> > +
> > +static unsigned int bits_reverse(u32 in_val, u8 bits)
> > +{
> > +	u32 out_val = 0;
> > +	u8 i;
> > +
> > +	for (i = 0; i < bits; i++) {
> > +		if (in_val & (1 << i))
> > +			out_val |= 1 << (bits - 1 - i);
> > +	}
> > +
> > +	return out_val;
> > +}
> > +
> > +static unsigned int get_crc(struct crc_config crc_cfg, const  u8 *buf, u64 buf_len)
> > +{
> > +	u8 width    = crc_cfg.width;
> > +	u32  poly   = crc_cfg.poly;
> > +	u32  crc    = crc_cfg.crc_init;
> > +	u32  xorout = crc_cfg.xor_out;
> > +	bool refin  = crc_cfg.ref_in;
> > +	bool refout = crc_cfg.ref_out;
> > +	u8 n;
> > +	u32  bits;
> > +	u32  data;
> > +	u8 i;
> > +
> > +	n    =  (width < 8) ? 0 : (width - 8);
> > +	crc  =  (width < 8) ? (crc << (8 - width)) : crc;
> > +	bits =  (width < 8) ? 0x80 : (1 << (width - 1));
> > +	poly =  (width < 8) ? (poly << (8 - width)) : poly;
> > +
> > +	while (buf_len--) {
> > +		data = *(buf++);
> > +		if (refin)
> > +			data = bits_reverse(data, 8);
> > +		crc ^= (data << n);
> > +		for (i = 0; i < 8; i++) {
> > +			if (crc & bits)
> > +				crc = (crc << 1) ^ poly;
> > +			else
> > +				crc = crc << 1;
> > +		}
> > +	}
> > +	crc = (width < 8) ? (crc >> (8 - width)) : crc;
> > +	if (refout)
> > +		crc = bits_reverse(crc, width);
> > +	crc ^= xorout;
> > +
> > +	return (crc & ((2 << (width - 1)) - 1));
> > +}
> 
> NAK for the manual CRC calculation. Use <linux/crc8.h>
done.  
> > +
> > +static u32 calculate_64K_crc(const u8 *upgrade_data, u64 len)
> > +{
> > +	struct crc_config crc_cfg = {
> > +		.width = 8,
> > +		.poly  = 0x31,
> > +		.crc_init = 0,
> > +		.xor_out = 0,
> > +		.ref_out = false,
> > +		.ref_in = false,
> > +	};
> > +	u64 crc_size = FW_64K_SIZE - 1;
> > +	u8 default_val = 0xFF;
> 
> Please use consistent style, It's recommended to use lower case hex.
done. 
> > +
> > +	crc_cfg.crc_init = get_crc(crc_cfg, upgrade_data, len);
> > +
> > +	crc_size -= len;
> > +	while (crc_size--)
> > +		crc_cfg.crc_init = get_crc(crc_cfg, &default_val, 1);
> > +
> > +	return crc_cfg.crc_init;
> > +}
> > +
> > +static u32 calculate_12K_crc(const u8 *upgrade_data, u64 len)
> > +{
> > +	struct crc_config crc_cfg = {
> > +		.width = 8,
> > +		.poly  = 0x31,
> > +		.crc_init = 0,
> > +		.xor_out = 0,
> > +		.ref_out = false,
> > +		.ref_in = false,
> > +	};
> > +	u64 crc_size = FW_12K_SIZE;
> > +	u8 default_val = 0xFF;
> > +
> > +	crc_cfg.crc_init = get_crc(crc_cfg, upgrade_data, len);
> > +
> > +	crc_size -= len;
> > +	while (crc_size--)
> > +		crc_cfg.crc_init = get_crc(crc_cfg, &default_val, 1);
> > +
> > +	return crc_cfg.crc_init;
> > +}
> 
> The only difference from the previous function is the crc_size. Merge
> them.
done. 
> > +
> > +static int lt8713sx_prepare_firmware_data(struct lt8713sx *lt8713sx)
> > +{
> > +	int ret = 0;
> > +
> > +	ret = request_firmware(&lt8713sx->fw, FW_FILE, lt8713sx->dev);
> > +	if (ret < 0) {
> > +		pr_err("request firmware failed\n");
> > +		return ret;
> > +	}
> > +
> > +	pr_debug("Firmware size: %zu bytes\n", lt8713sx->fw->size);
> > +
> > +	if (lt8713sx->fw->size > FW_256K_SIZE - 1) {
> > +		pr_err("Firmware size exceeds 256KB limit\n");
> > +		release_firmware(lt8713sx->fw);
> > +		return -EINVAL;
> > +	}
> > +
> > +	lt8713sx->fw_buffer = kzalloc(FW_256K_SIZE, GFP_KERNEL);
> 
> I think 256k is already big enough to be used for vmalloc instead. Also,
> there is no need to zero-fill it, if you are going to fill it with 0xff
> in the next line.
done. 
> > +	if (!lt8713sx->fw_buffer) {
> > +		release_firmware(lt8713sx->fw);
> > +		return -ENOMEM;
> > +	}
> > +
> > +	memset(lt8713sx->fw_buffer, 0xFF, FW_256K_SIZE);
> > +
> > +	if (lt8713sx->fw->size < FW_64K_SIZE) {
> > +		/*TODO: CRC should be calculated with 0xff also */
> 
> Is this still relevant?
removed it. 
> > +		memcpy(lt8713sx->fw_buffer, lt8713sx->fw->data, lt8713sx->fw->size);
> > +		lt8713sx->fw_buffer[FW_64K_SIZE - 1] =
> > +				calculate_64K_crc(lt8713sx->fw->data, lt8713sx->fw->size);
> 
> You have already put your firmware into 0xff-filled 256k buffer. It's
> safe to pass SZ_64K here. Then you can drop the 'tail' CRC calculation
> from calculate_64K_crc() and calculate_12K_crc().
I tried doing this, CRC calculation in driver is not matching with the CRC values returned from HW.
Existing calculation is as per bridge chip requirement and HW is always returning the same CRC.
I have updated crc calculation using linux/crc8.h in next patch.

> > +		lt8713sx->main_crc_value = lt8713sx->fw_buffer[FW_64K_SIZE - 1];
> > +		pr_debug("Main Firmware Data  Crc=0x%02X\n", lt8713sx->main_crc_value);
> > +
> > +	} else {
> > +		//main firmware
> > +		memcpy(lt8713sx->fw_buffer, lt8713sx->fw->data, FW_64K_SIZE - 1);
> > +		lt8713sx->fw_buffer[FW_64K_SIZE - 1] =
> > +				calculate_64K_crc(lt8713sx->fw_buffer, FW_64K_SIZE - 1);
> > +		lt8713sx->main_crc_value = lt8713sx->fw_buffer[FW_64K_SIZE - 1];
> > +		pr_debug("Main Firmware Data  Crc=0x%02X\n", lt8713sx->main_crc_value);
> > +
> > +		//bank firmware
> > +		memcpy(lt8713sx->fw_buffer + FW_64K_SIZE,
> > +		       lt8713sx->fw->data + FW_64K_SIZE,
> > +		       lt8713sx->fw->size - FW_64K_SIZE);
> > +
> > +		lt8713sx->bank_num = (lt8713sx->fw->size - FW_64K_SIZE + FW_12K_SIZE - 1) /
> > +					FW_12K_SIZE;
> > +		pr_debug("Bank Number Total is %d.\n", lt8713sx->bank_num);
> > +
> > +		for (int i = 0; i < lt8713sx->bank_num; i++) {
> > +			lt8713sx->bank_crc_value[i] =
> > +				calculate_12K_crc(lt8713sx->fw_buffer + FW_64K_SIZE +
> > +						  i * FW_12K_SIZE,
> > +						  FW_12K_SIZE);
> > +			pr_debug("Bank number:%d; Firmware Data  Crc:0x%02X\n",
> > +				 i, lt8713sx->bank_crc_value[i]);
> > +		}
> > +	}
> > +	return 0;
> > +}
> > +
> > +static void lt8713sx_config_parameters(struct lt8713sx *lt8713sx)
> > +{
> > +	regmap_write(lt8713sx->regmap, 0xFF, 0xE0);
> > +	regmap_write(lt8713sx->regmap, 0xEE, 0x01);
> > +	regmap_write(lt8713sx->regmap, 0x5E, 0xC1);
> > +	regmap_write(lt8713sx->regmap, 0x58, 0x00);
> > +	regmap_write(lt8713sx->regmap, 0x59, 0x50);
> > +	regmap_write(lt8713sx->regmap, 0x5A, 0x10);
> > +	regmap_write(lt8713sx->regmap, 0x5A, 0x00);
> > +	regmap_write(lt8713sx->regmap, 0x58, 0x21);
> > +}
> > +
> > +static void lt8713sx_wren(struct lt8713sx *lt8713sx)
> > +{
> > +	regmap_write(lt8713sx->regmap, 0xff, 0xe1);
> > +	regmap_write(lt8713sx->regmap, 0x03, 0xbf);
> > +	regmap_write(lt8713sx->regmap, 0x03, 0xff);
> > +	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
> > +	regmap_write(lt8713sx->regmap, 0x5a, 0x04);
> > +	regmap_write(lt8713sx->regmap, 0x5a, 0x00);
> > +}
> > +
> > +static void lt8713sx_wrdi(struct lt8713sx *lt8713sx)
> > +{
> > +	regmap_write(lt8713sx->regmap, 0x5A, 0x08);
> > +	regmap_write(lt8713sx->regmap, 0x5A, 0x00);
> > +}
> > +
> > +static void lt8713sx_fifo_reset(struct lt8713sx *lt8713sx)
> > +{
> > +	regmap_write(lt8713sx->regmap, 0xff, 0xe1);
> > +	regmap_write(lt8713sx->regmap, 0x03, 0xbf);
> > +	regmap_write(lt8713sx->regmap, 0x03, 0xff);
> > +}
> > +
> > +static void lt8713sx_disable_sram_write(struct lt8713sx *lt8713sx)
> > +{
> > +	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
> > +	regmap_write(lt8713sx->regmap, 0x55, 0x00);
> > +}
> > +
> > +static void lt8713sx_sram_to_flash(struct lt8713sx *lt8713sx)
> > +{
> > +	regmap_write(lt8713sx->regmap, 0x5a, 0x30);
> > +	regmap_write(lt8713sx->regmap, 0x5a, 0x00);
> > +}
> > +
> > +static void lt8713sx_i2c_to_sram(struct lt8713sx *lt8713sx)
> > +{
> > +	regmap_write(lt8713sx->regmap, 0x55, 0x80);
> > +	regmap_write(lt8713sx->regmap, 0x5e, 0xc0);
> > +	regmap_write(lt8713sx->regmap, 0x58, 0x21);
> > +}
> > +
> > +static u8 lt8713sx_read_flash_status(struct lt8713sx *lt8713sx)
> > +{
> > +	u32 flash_status = 0;
> > +
> > +	regmap_write(lt8713sx->regmap,  0xFF, 0xE1);//fifo_rst_n
> > +	regmap_write(lt8713sx->regmap,  0x03, 0x3F);
> > +	regmap_write(lt8713sx->regmap,  0x03, 0xFF);
> > +
> > +	regmap_write(lt8713sx->regmap,  0xFF, 0xE0);
> > +	regmap_write(lt8713sx->regmap,  0x5e, 0x40);
> > +	regmap_write(lt8713sx->regmap,  0x56, 0x05);//opcode=read status register
> > +	regmap_write(lt8713sx->regmap,  0x55, 0x25);
> > +	regmap_write(lt8713sx->regmap,  0x55, 0x01);
> > +	regmap_write(lt8713sx->regmap,  0x58, 0x21);
> > +
> > +	regmap_read(lt8713sx->regmap, 0x5f, &flash_status);
> > +	pr_debug("flash_status:%x\n", flash_status);
> > +
> > +	return flash_status;
> > +}
> > +
> > +static void lt8713sx_block_erase(struct lt8713sx *lt8713sx)
> > +{
> > +	u32 i = 0;
> > +	u8 flash_status = 0;
> > +	u8 blocknum = 0x00;
> > +	u32 flashaddr = 0x00;
> > +
> > +	for (blocknum = 0; blocknum < 8; blocknum++) {
> > +		flashaddr = blocknum * 0x008000;
> 
> SZ_32K
done. 
> > +		regmap_write(lt8713sx->regmap,  0xFF, 0xE0);
> > +		regmap_write(lt8713sx->regmap,  0xEE, 0x01);
> > +		regmap_write(lt8713sx->regmap,  0x5A, 0x04);
> > +		regmap_write(lt8713sx->regmap,  0x5A, 0x00);
> > +		regmap_write(lt8713sx->regmap,  0x5B, flashaddr >> 16);//set flash address[23:16]
> > +		regmap_write(lt8713sx->regmap,  0x5C, flashaddr >> 8);//set flash address[15:8]
> > +		regmap_write(lt8713sx->regmap,  0x5D, flashaddr);//set flash address[7:0]
> > +		regmap_write(lt8713sx->regmap,  0x5A, 0x01);
> > +		regmap_write(lt8713sx->regmap,  0x5A, 0x00);
> > +		msleep(100); //delay 100ms
> 
> Please drop useless comments. It's clear that msleep delays for 100ms.
done. 
> > +		i = 0;
> > +		while (1) {
> > +			flash_status = lt8713sx_read_flash_status(lt8713sx); //wait erase finish
> > +			if ((flash_status & 0x01) == 0)
> > +				break;
> > +
> > +			if (i > 50)
> > +				break;
> > +
> > +			i++;
> > +			msleep(50); //delay 50ms
> > +		}
> > +	}
> > +	pr_debug("erase flash done.\n");
> > +}
> > +
> > +static void lt8713sx_load_main_fw_to_sram(struct lt8713sx *lt8713sx)
> > +{
> > +	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
> > +	regmap_write(lt8713sx->regmap, 0xee, 0x01);
> > +	regmap_write(lt8713sx->regmap, 0x68, 0x00);
> > +	regmap_write(lt8713sx->regmap, 0x69, 0x00);
> > +	regmap_write(lt8713sx->regmap, 0x6a, 0x00);
> > +	regmap_write(lt8713sx->regmap, 0x65, 0x00);
> > +	regmap_write(lt8713sx->regmap, 0x66, 0xff);
> > +	regmap_write(lt8713sx->regmap, 0x67, 0xff);
> > +	regmap_write(lt8713sx->regmap, 0x6b, 0x00);
> > +	regmap_write(lt8713sx->regmap, 0x6c, 0x00);
> > +	regmap_write(lt8713sx->regmap, 0x60, 0x01);
> > +	msleep(200);
> > +	regmap_write(lt8713sx->regmap, 0x60, 0x00);
> > +}
> > +
> > +static void lt8713sx_load_bank_fw_to_sram(struct lt8713sx *lt8713sx, u64 addr)
> > +{
> > +	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
> > +	regmap_write(lt8713sx->regmap, 0xee, 0x01);
> > +	regmap_write(lt8713sx->regmap, 0x68, ((addr & 0xFF0000) >> 16));
> > +	regmap_write(lt8713sx->regmap, 0x69, ((addr & 0x00FF00) >> 8));
> > +	regmap_write(lt8713sx->regmap, 0x6a, (addr & 0x0000FF));
> > +	regmap_write(lt8713sx->regmap, 0x65, 0x00);
> > +	regmap_write(lt8713sx->regmap, 0x66, 0x30);
> > +	regmap_write(lt8713sx->regmap, 0x67, 0x00);
> > +	regmap_write(lt8713sx->regmap, 0x6b, 0x00);
> > +	regmap_write(lt8713sx->regmap, 0x6c, 0x00);
> > +	regmap_write(lt8713sx->regmap, 0x60, 0x01);
> > +	msleep(50);
> > +	regmap_write(lt8713sx->regmap, 0x60, 0x00);
> > +}
> > +
> > +static int lt8713sx_write_data(struct lt8713sx *lt8713sx, const u8 *data, u64 filesize)
> > +{
> > +	int page = 0, num = 0, i = 0, val;
> > +
> > +	page = (filesize % LT8713SX_PAGE_SIZE) ?
> > +			((filesize / LT8713SX_PAGE_SIZE) + 1) : (filesize / LT8713SX_PAGE_SIZE);
> > +
> > +	pr_debug("Writing to Sram=%u pages, total size = %llu bytes\n", page, filesize);
> > +
> > +	for (num = 0; num < page; num++) {
> > +		pr_debug("page[%d]\n", num);
> > +		lt8713sx_i2c_to_sram(lt8713sx);
> > +
> > +		for (i = 0; i < LT8713SX_PAGE_SIZE; i++) {
> > +			if ((num * LT8713SX_PAGE_SIZE + i) < filesize)
> > +				val = *(data + (num * LT8713SX_PAGE_SIZE + i));
> > +			else
> > +				val = 0xFF;
> > +			regmap_write(lt8713sx->regmap, 0x59, val);
> > +		}
> > +
> > +		lt8713sx_wren(lt8713sx);
> > +		lt8713sx_sram_to_flash(lt8713sx);
> > +	}
> > +
> > +	lt8713sx_wrdi(lt8713sx);
> > +	lt8713sx_disable_sram_write(lt8713sx);
> > +
> > +	return 0;
> > +}
> > +
> > +static void lt8713sx_main_upgrade_result(struct lt8713sx *lt8713sx)
> > +{
> > +	u32 main_crc_result;
> > +
> > +	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
> > +	regmap_read(lt8713sx->regmap, 0x23, &main_crc_result);
> > +
> > +	pr_debug("Main CRC HW: 0x%02X\n", main_crc_result);
> > +	pr_debug("Main CRC FW: 0x%02X\n", lt8713sx->main_crc_value);
> > +
> > +	if (main_crc_result == lt8713sx->main_crc_value)
> > +		pr_debug("Main Firmware Upgrade Success.\n");
> > +	else
> > +		pr_err("Main Firmware Upgrade Failed.\n");
> > +}
> > +
> > +static void lt8713sx_bank_upgrade_result(struct lt8713sx *lt8713sx, u8 banknum)
> > +{
> > +	u32 bank_crc_result;
> > +
> > +	regmap_write(lt8713sx->regmap, 0xff, 0xe0);
> > +
> > +	regmap_read(lt8713sx->regmap, 0x23, &bank_crc_result);
> > +
> > +	pr_debug("Bank %d CRC Result: 0x%02X\n", banknum, bank_crc_result);
> > +
> > +	if (bank_crc_result == lt8713sx->bank_crc_value[banknum])
> > +		pr_debug("Bank %d Firmware Upgrade Success.\n", banknum);
> > +	else
> > +		pr_err("Bank %d Firmware Upgrade Failed.\n", banknum);
> > +}
> > +
> > +static void lt8713sx_bank_result_check(struct lt8713sx *lt8713sx)
> > +{
> > +	int i;
> > +	u64 addr = 0x010000;
> > +
> > +	for (i = 0; i < lt8713sx->bank_num; i++) {
> > +		lt8713sx_load_bank_fw_to_sram(lt8713sx, addr);
> > +		lt8713sx_bank_upgrade_result(lt8713sx, i);
> > +		addr += 0x3000;
> > +	}
> > +}
> > +
> > +static int lt8713sx_firmware_upgrade(struct lt8713sx *lt8713sx)
> > +{
> > +	int ret;
> > +
> > +	lt8713sx_config_parameters(lt8713sx);
> > +
> > +	lt8713sx_block_erase(lt8713sx);
> > +
> > +	if (lt8713sx->fw->size < FW_64K_SIZE) {
> > +		ret = lt8713sx_write_data(lt8713sx, lt8713sx->fw_buffer, FW_64K_SIZE);
> > +		if (ret < 0) {
> > +			pr_err("Failed to write firmware data: %d\n", ret);
> > +			return ret;
> > +		}
> > +	} else {
> > +		ret = lt8713sx_write_data(lt8713sx, lt8713sx->fw_buffer, lt8713sx->fw->size);
> > +		if (ret < 0) {
> > +			pr_err("Failed to write firmware data: %d\n", ret);
> > +			return ret;
> > +		}
> > +	}
> > +
> > +	pr_debug("Write Data done.\n");
> > +
> > +	return 0;
> > +}
> > +
> > +static int lt8713sx_firmware_update(struct lt8713sx *lt8713sx)
> > +{
> > +	int ret = 0;
> > +
> > +	mutex_lock(&lt8713sx->ocm_lock);
> > +	lt8713sx_i2c_enable(lt8713sx);
> > +
> > +	ret = lt8713sx_prepare_firmware_data(lt8713sx);
> > +	if (ret < 0) {
> > +		pr_err("Failed to prepare firmware data: %d\n", ret);
> > +		goto error;
> > +	}
> > +
> > +	ret = lt8713sx_firmware_upgrade(lt8713sx);
> > +	if (ret < 0) {
> > +		pr_err("Upgrade failure.\n");
> > +		goto error;
> > +	} else {
> > +		/* Validate CRC */
> > +		lt8713sx_load_main_fw_to_sram(lt8713sx);
> > +		lt8713sx_main_upgrade_result(lt8713sx);
> > +		lt8713sx_wrdi(lt8713sx);
> > +		lt8713sx_fifo_reset(lt8713sx);
> > +		lt8713sx_bank_result_check(lt8713sx);
> > +		lt8713sx_wrdi(lt8713sx);
> > +	}
> > +
> > +error:
> > +	lt8713sx_i2c_disable(lt8713sx);
> > +	if (!ret)
> > +		lt8713sx_reset(lt8713sx);
> > +
> > +	kfree(lt8713sx->fw_buffer);
> > +	lt8713sx->fw_buffer = NULL;
> > +
> > +	if (lt8713sx->fw) {
> > +		release_firmware(lt8713sx->fw);
> > +		lt8713sx->fw = NULL;
> > +	}
> > +	mutex_unlock(&lt8713sx->ocm_lock);
> > +
> > +	return ret;
> > +}
> > +
> > +static void lt8713sx_reset(struct lt8713sx *lt8713sx)
> > +{
> > +	pr_debug("reset bridge.\n");
> > +	gpiod_set_value_cansleep(lt8713sx->reset_gpio, 1);
> > +	msleep(20);
> > +
> > +	gpiod_set_value_cansleep(lt8713sx->reset_gpio, 0);
> > +	msleep(20);
> > +
> > +	gpiod_set_value_cansleep(lt8713sx->reset_gpio, 1);
> > +	msleep(20);
> > +	pr_debug("reset done.\n");
> > +}
> > +
> > +static int lt8713sx_regulator_init(struct lt8713sx *lt8713sx)
> > +{
> > +	int ret;
> > +
> > +	lt8713sx->supplies[0].supply = "vdd";
> > +	lt8713sx->supplies[1].supply = "vcc";
> > +
> > +	ret = devm_regulator_bulk_get(lt8713sx->dev, 2, lt8713sx->supplies);
> > +	if (ret < 0)
> > +		return dev_err_probe(lt8713sx->dev, ret, "failed to get regulators\n");
> > +
> > +	ret = regulator_set_load(lt8713sx->supplies[0].consumer, 200000);
> > +	if (ret < 0)
> > +		return dev_err_probe(lt8713sx->dev, ret, "failed to set regulator load\n");
> > +
> > +	return 0;
> > +}
> > +
> > +static int lt8713sx_regulator_enable(struct lt8713sx *lt8713sx)
> > +{
> > +	int ret;
> > +
> > +	ret = regulator_enable(lt8713sx->supplies[0].consumer);
> > +	if (ret < 0)
> > +		return dev_err_probe(lt8713sx->dev, ret, "failed to enable vdd regulator\n");
> > +
> > +	usleep_range(1000, 10000);
> > +
> > +	ret = regulator_enable(lt8713sx->supplies[1].consumer);
> > +	if (ret < 0) {
> > +		regulator_disable(lt8713sx->supplies[0].consumer);
> > +		return dev_err_probe(lt8713sx->dev, ret, "failed to enable vcc regulator\n");
> > +	}
> > +	return 0;
> > +}
> > +
> > +static int lt8713sx_gpio_init(struct lt8713sx *lt8713sx)
> > +{
> > +	struct device *dev = lt8713sx->dev;
> > +
> > +	lt8713sx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> > +	if (IS_ERR(lt8713sx->reset_gpio))
> > +		return dev_err_probe(dev, PTR_ERR(lt8713sx->reset_gpio),
> > +				     "failed to acquire reset gpio\n");
> > +
> > +	/* power enable gpio */
> > +	lt8713sx->enable_gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_HIGH);
> > +	if (IS_ERR(lt8713sx->enable_gpio))
> > +		return dev_err_probe(dev, PTR_ERR(lt8713sx->enable_gpio),
> > +				     "failed to acquire enable gpio\n");
> > +	return 0;
> > +}
> > +
> > +static ssize_t lt8713sx_firmware_store(struct device *dev,
> > +				       struct device_attribute *attr,
> > +				       const char *buf, size_t len)
> > +{
> > +	struct lt8713sx *lt8713sx = dev_get_drvdata(dev);
> > +	int ret;
> > +
> > +	ret = lt8713sx_firmware_update(lt8713sx);
> > +	if (ret < 0)
> > +		return ret;
> > +	return len;
> > +}
> > +
> > +static DEVICE_ATTR_WO(lt8713sx_firmware);
> > +
> > +static struct attribute *lt8713sx_attrs[] = {
> > +	&dev_attr_lt8713sx_firmware.attr,
> > +	NULL,
> > +};
> > +
> > +static const struct attribute_group lt8713sx_attr_group = {
> > +	.attrs = lt8713sx_attrs,
> > +};
> > +
> > +static const struct attribute_group *lt8713sx_attr_groups[] = {
> > +	&lt8713sx_attr_group,
> > +	NULL,
> > +};
> > +
> > +static int lt8713sx_probe(struct i2c_client *client)
> > +{
> > +	struct lt8713sx *lt8713sx;
> > +	struct device *dev = &client->dev;
> > +	int ret;
> > +
> > +	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
> > +		return dev_err_probe(dev, -ENODEV, "device doesn't support I2C\n");
> > +
> > +	lt8713sx = devm_kzalloc(dev, sizeof(*lt8713sx), GFP_KERNEL);
> > +	if (!lt8713sx)
> > +		return dev_err_probe(dev, -ENOMEM, "failed to allocate lt8713sx struct\n");
> > +
> > +	lt8713sx->dev = dev;
> > +	lt8713sx->client = client;
> > +	i2c_set_clientdata(client, lt8713sx);
> > +
> > +	mutex_init(&lt8713sx->ocm_lock);
> 
> devm_mutex_init().
done. 
> > +
> > +	lt8713sx->regmap = devm_regmap_init_i2c(client, &lt8713sx_regmap_config);
> > +	if (IS_ERR(lt8713sx->regmap))
> > +		return dev_err_probe(dev, PTR_ERR(lt8713sx->regmap), "regmap i2c init failed\n");
> > +
> > +	ret = lt8713sx_gpio_init(lt8713sx);
> > +	if (ret < 0)
> > +		goto err_of_put;
> 
> err_of_put is just a return. Please inline it.
done. 
> > +
> > +	ret = lt8713sx_regulator_init(lt8713sx);
> > +	if (ret < 0)
> > +		goto err_of_put;
> > +
> > +	ret = lt8713sx_regulator_enable(lt8713sx);
> > +	if (ret)
> > +		goto err_of_put;
> > +
> > +	lt8713sx_reset(lt8713sx);
> > +
> > +	return 0;
> > +
> > +err_of_put:
> > +	return ret;
> > +}
> > +
> > +static void lt8713sx_remove(struct i2c_client *client)
> > +{
> > +	struct lt8713sx *lt8713sx = i2c_get_clientdata(client);
> > +
> > +	mutex_destroy(&lt8713sx->ocm_lock);
> > +
> > +	regulator_bulk_disable(ARRAY_SIZE(lt8713sx->supplies), lt8713sx->supplies);
> 
> Use devm_regulator_get_enable(), then you can drop this line.
done. 
> > +}
> > +
> > +static struct i2c_device_id lt8713sx_id[] = {
> > +	{ "lontium,lt8713sx", 0 },
> > +	{ /* sentinel */ }
> > +};
> > +
> > +static const struct of_device_id lt8713sx_match_table[] = {
> > +	{ .compatible = "lontium,lt8713sx" },
> > +	{ /* sentinel */ }
> > +};
> > +MODULE_DEVICE_TABLE(of, lt8713sx_match_table);
> > +
> > +static struct i2c_driver lt8713sx_driver = {
> > +	.driver = {
> > +		.name = "lt8713sx",
> > +		.of_match_table = lt8713sx_match_table,
> > +		.dev_groups = lt8713sx_attr_groups,
> > +	},
> > +	.probe = lt8713sx_probe,
> > +	.remove = lt8713sx_remove,
> > +	.id_table = lt8713sx_id,
> > +};
> > +
> > +module_i2c_driver(lt8713sx_driver);
> > +MODULE_LICENSE("GPL");
> > +MODULE_DESCRIPTION("lt8713sx drm bridge driver");
> > +MODULE_AUTHOR("Tony <syyang@lontium.com>");
> > +MODULE_FIRMWARE(FW_FILE);
> > 
> > -- 
> > 2.34.1
> >  
> -- 
> With best wishes
> Dmitry