drivers/gpu/drm/nouveau/nvkm/subdev/bios/i2c.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/nouveau/nvkm/subdev/bios/i2c.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/nouveau/nvkm/subdev/bios/i2c.c
Extension
.c
Size
4773 bytes
Lines
165
Domain
Driver Families
Bucket
drivers/gpu
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (ver >= 0x41) {
			u32 ent_value = nvbios_rd32(bios, ent);
			u8 i2c_port = (ent_value >> 0) & 0x1f;
			u8 dpaux_port = (ent_value >> 5) & 0x1f;
			/* value 0x1f means unused according to DCB 4.x spec */
			if (i2c_port == 0x1f && dpaux_port == 0x1f)
				info->type = DCB_I2C_UNUSED;
			else
				info->type = DCB_I2C_PMGR;
		} else
		if (ver >= 0x30) {
			info->type = nvbios_rd08(bios, ent + 0x03);
		} else {
			info->type = nvbios_rd08(bios, ent + 0x03) & 0x07;
			if (info->type == 0x07)
				info->type = DCB_I2C_UNUSED;
		}

		info->drive = DCB_I2C_UNUSED;
		info->sense = DCB_I2C_UNUSED;
		info->share = DCB_I2C_UNUSED;
		info->auxch = DCB_I2C_UNUSED;

		switch (info->type) {
		case DCB_I2C_NV04_BIT:
			info->drive = nvbios_rd08(bios, ent + 0);
			info->sense = nvbios_rd08(bios, ent + 1);
			return 0;
		case DCB_I2C_NV4E_BIT:
			info->drive = nvbios_rd08(bios, ent + 1);
			return 0;
		case DCB_I2C_NVIO_BIT:
			info->drive = nvbios_rd08(bios, ent + 0) & 0x0f;
			if (nvbios_rd08(bios, ent + 1) & 0x01)
				info->share = nvbios_rd08(bios, ent + 1) >> 1;
			return 0;
		case DCB_I2C_NVIO_AUX:
			info->auxch = nvbios_rd08(bios, ent + 0) & 0x0f;
			if (nvbios_rd08(bios, ent + 1) & 0x01)
					info->share = info->auxch;
			return 0;
		case DCB_I2C_PMGR:
			info->drive = (nvbios_rd16(bios, ent + 0) & 0x01f) >> 0;
			if (info->drive == 0x1f)
				info->drive = DCB_I2C_UNUSED;
			info->auxch = (nvbios_rd16(bios, ent + 0) & 0x3e0) >> 5;
			if (info->auxch == 0x1f)
				info->auxch = DCB_I2C_UNUSED;
			info->share = info->auxch;
			return 0;
		case DCB_I2C_UNUSED:
			return 0;
		default:
			nvkm_warn(subdev, "unknown i2c type %d\n", info->type);
			info->type = DCB_I2C_UNUSED;
			return 0;
		}
	}

	if (bios->bmp_offset && idx < 2) {
		/* BMP (from v4.0 has i2c info in the structure, it's in a
		 * fixed location on earlier VBIOS
		 */
		if (nvbios_rd08(bios, bios->bmp_offset + 5) < 4)
			ent = 0x0048;
		else
			ent = 0x0036 + bios->bmp_offset;

		if (idx == 0) {
			info->drive = nvbios_rd08(bios, ent + 4);
			if (!info->drive) info->drive = 0x3f;
			info->sense = nvbios_rd08(bios, ent + 5);
			if (!info->sense) info->sense = 0x3e;
		} else
		if (idx == 1) {
			info->drive = nvbios_rd08(bios, ent + 6);
			if (!info->drive) info->drive = 0x37;
			info->sense = nvbios_rd08(bios, ent + 7);
			if (!info->sense) info->sense = 0x36;
		}

		info->type  = DCB_I2C_NV04_BIT;
		info->share = DCB_I2C_UNUSED;
		return 0;
	}

	return -ENOENT;
}

Annotation

Implementation Notes