drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.c
Extension
.c
Size
3727 bytes
Lines
168
Domain
Driver Families
Bucket
drivers/gpu
Inferred role
Driver Families: exported/initcall integration point
Status
integration 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 (time_after(jiffies, timeout)) {
			if (!anx_dp_aux_op_finished(map_dptx)) {
				DRM_ERROR("Timed out waiting AUX to finish\n");
				return -ETIMEDOUT;
			}

			break;
		}

		usleep_range(1000, 2000);
	}

	/* Read the AUX channel access status */
	err = regmap_read(map_dptx, SP_AUX_CH_STATUS_REG, &status);
	if (err < 0) {
		DRM_ERROR("Failed to read from AUX channel: %d\n", err);
		return err;
	}

	if (status & SP_AUX_STATUS) {
		DRM_ERROR("Failed to wait for AUX channel (status: %02x)\n",
			  status);
		return -ETIMEDOUT;
	}

	return 0;
}

static int anx_dp_aux_address(struct regmap *map_dptx, unsigned int addr)
{
	int err;

	err = regmap_write(map_dptx, SP_AUX_ADDR_7_0_REG, addr & 0xff);
	if (err)
		return err;

	err = regmap_write(map_dptx, SP_AUX_ADDR_15_8_REG,
			   (addr & 0xff00) >> 8);
	if (err)
		return err;

	/*
	 * DP AUX CH Address Register #2, only update bits[3:0]
	 * [7:4] RESERVED
	 * [3:0] AUX_ADDR[19:16], Register control AUX CH address.
	 */
	err = regmap_update_bits(map_dptx, SP_AUX_ADDR_19_16_REG,
				 SP_AUX_ADDR_19_16_MASK,
				 (addr & 0xf0000) >> 16);

	if (err)
		return err;

	return 0;
}

ssize_t anx_dp_aux_transfer(struct regmap *map_dptx,
				struct drm_dp_aux_msg *msg)
{
	u8 ctrl1 = msg->request;
	u8 ctrl2 = SP_AUX_EN;
	u8 *buffer = msg->buffer;
	int err;

	/* The DP AUX transmit and receive buffer has 16 bytes. */
	if (WARN_ON(msg->size > AUX_CH_BUFFER_SIZE))
		return -E2BIG;

	/* Zero-sized messages specify address-only transactions. */
	if (msg->size < 1)
		ctrl2 |= SP_ADDR_ONLY;
	else	/* For non-zero-sized set the length field. */
		ctrl1 |= (msg->size - 1) << SP_AUX_LENGTH_SHIFT;

	if ((msg->size > 0) && ((msg->request & DP_AUX_I2C_READ) == 0)) {
		/* When WRITE | MOT write values to data buffer */
		err = regmap_bulk_write(map_dptx,
					SP_DP_BUF_DATA0_REG, buffer,
					msg->size);
		if (err)
			return err;
	}

	/* Write address and request */
	err = anx_dp_aux_address(map_dptx, msg->address);
	if (err)
		return err;

	err = regmap_write(map_dptx, SP_DP_AUX_CH_CTRL1_REG, ctrl1);
	if (err)

Annotation

Implementation Notes