drivers/gpu/drm/amd/amdgpu/atombios_i2c.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/amd/amdgpu/atombios_i2c.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/amd/amdgpu/atombios_i2c.c
Extension
.c
Size
4912 bytes
Lines
177
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 (num > ATOM_MAX_HW_I2C_WRITE) {
			DRM_ERROR("hw i2c: tried to write too many bytes (%d vs 3)\n", num);
			r = -EINVAL;
			goto done;
		}
		if (buf == NULL)
			args.ucRegIndex = 0;
		else
			args.ucRegIndex = buf[0];
		if (num)
			num--;
		if (num) {
			if (buf) {
				memcpy(&out, &buf[1], num);
			} else {
				DRM_ERROR("hw i2c: missing buf with num > 1\n");
				r = -EINVAL;
				goto done;
			}
		}
		args.lpI2CDataOut = cpu_to_le16(out);
	} else {
		args.ucRegIndex = 0;
		args.lpI2CDataOut = 0;
	}

	args.ucFlag = flags;
	args.ucI2CSpeed = TARGET_HW_I2C_CLOCK;
	args.ucTransBytes = num;
	args.ucSlaveAddr = slave_addr << 1;
	args.ucLineNumber = chan->rec.i2c_id;

	amdgpu_atom_execute_table(adev->mode_info.atom_context, index, (uint32_t *)&args, sizeof(args));

	/* error */
	if (args.ucStatus != HW_ASSISTED_I2C_STATUS_SUCCESS) {
		DRM_DEBUG_KMS("hw_i2c error\n");
		r = -EIO;
		goto done;
	}

	if (!(flags & HW_I2C_WRITE))
		amdgpu_atombios_copy_swap(buf, base, num, false);

done:
	mutex_unlock(&chan->mutex);

	return r;
}

int amdgpu_atombios_i2c_xfer(struct i2c_adapter *i2c_adap,
		      struct i2c_msg *msgs, int num)
{
	struct amdgpu_i2c_chan *i2c = i2c_get_adapdata(i2c_adap);
	struct i2c_msg *p;
	int i, remaining, current_count, buffer_offset, max_bytes, ret;
	u8 flags;

	/* check for bus probe */
	p = &msgs[0];
	if ((num == 1) && (p->len == 0)) {
		ret = amdgpu_atombios_i2c_process_i2c_ch(i2c,
						  p->addr, HW_I2C_WRITE,
						  NULL, 0);
		if (ret)
			return ret;
		else
			return num;
	}

	for (i = 0; i < num; i++) {
		p = &msgs[i];
		remaining = p->len;
		buffer_offset = 0;
		/* max_bytes are a limitation of ProcessI2cChannelTransaction not the hw */
		if (p->flags & I2C_M_RD) {
			max_bytes = ATOM_MAX_HW_I2C_READ;
			flags = HW_I2C_READ;
		} else {
			max_bytes = ATOM_MAX_HW_I2C_WRITE;
			flags = HW_I2C_WRITE;
		}
		while (remaining) {
			if (remaining > max_bytes)
				current_count = max_bytes;
			else
				current_count = remaining;
			ret = amdgpu_atombios_i2c_process_i2c_ch(i2c,
							  p->addr, flags,
							  &p->buf[buffer_offset], current_count);

Annotation

Implementation Notes