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Commit a009c53e authored by Philippe Cornu's avatar Philippe Cornu Committed by Andrzej Hajda
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drm/bridge/synopsys: dsi: Add read feature 



This patch adds the DCS/GENERIC DSI read feature.

Signed-off-by: default avatarPhilippe Cornu <philippe.cornu@st.com>
Reviewed-by: default avatarAndrzej Hajda <a.hajda@samsung.com>
Reviewed-by: default avatarBrian Norris <briannorris@chromium.org>
Signed-off-by: default avatarAndrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180204213104.17834-1-philippe.cornu@st.com
parent 3b6ec458

drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c

+45 −13
Original line number Diff line number Diff line
@@ -391,18 +391,46 @@ static int dw_mipi_dsi_write(struct dw_mipi_dsi *dsi, 
	return dw_mipi_dsi_gen_pkt_hdr_write(dsi, le32_to_cpu(word));

}



static int dw_mipi_dsi_read(struct dw_mipi_dsi *dsi,

			    const struct mipi_dsi_msg *msg)

{

	int i, j, ret, len = msg->rx_len;

	u8 *buf = msg->rx_buf;

	u32 val;



	/* Wait end of the read operation */

	ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,

				 val, !(val & GEN_RD_CMD_BUSY),

				 1000, CMD_PKT_STATUS_TIMEOUT_US);

	if (ret) {

		dev_err(dsi->dev, "Timeout during read operation\n");

		return ret;

	}



	for (i = 0; i < len; i += 4) {

		/* Read fifo must not be empty before all bytes are read */

		ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,

					 val, !(val & GEN_PLD_R_EMPTY),

					 1000, CMD_PKT_STATUS_TIMEOUT_US);

		if (ret) {

			dev_err(dsi->dev, "Read payload FIFO is empty\n");

			return ret;

		}



		val = dsi_read(dsi, DSI_GEN_PLD_DATA);

		for (j = 0; j < 4 && j + i < len; j++)

			buf[i + j] = val >> (8 * j);

	}



	return ret;

}



static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,

					 const struct mipi_dsi_msg *msg)

{

	struct dw_mipi_dsi *dsi = host_to_dsi(host);

	struct mipi_dsi_packet packet;

	int ret;



	if (msg->rx_buf || msg->rx_len) {

		/* TODO dw drv improvements: implement read feature */

		dev_warn(dsi->dev, "read operations not yet implemented\n");

		return -EINVAL;

	}

	int ret, nb_bytes;



	ret = mipi_dsi_create_packet(&packet, msg);

	if (ret) {
@@ -416,12 +444,16 @@ static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host, 
	if (ret)

		return ret;



	/*

	 * TODO Only transmitted size is returned as actual driver does

	 * not support dcs/generic reads. Please update return value when

	 * delivering the read feature.

	 */

	return packet.size;

	if (msg->rx_buf && msg->rx_len) {

		ret = dw_mipi_dsi_read(dsi, msg);

		if (ret)

			return ret;

		nb_bytes = msg->rx_len;

	} else {

		nb_bytes = packet.size;

	}



	return nb_bytes;

}



static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {