[PATCH 26/26] drm/rockchip: dw-mipi-dsi: support read commands

John Keeping
2016-09-19T17:17:47Z

I haven't found any method for getting the length of a response, so this
just uses the requested rx_len

Signed-off-by: John Keeping <john@metanate.com>
---
drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 54 ++++++++++++++++++++++++++++++++++
1 file changed, 54 insertions(+)

diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
index d0b2f6e9517d..6dc43c024bca 100644
--- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
@@ -676,6 +676,54 @@ static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi,
return dw_mipi_dsi_gen_pkt_hdr_write(dsi, hdr_val);
}

+static int dw_mipi_dsi_dcs_read(struct dw_mipi_dsi *dsi,
+ const struct mipi_dsi_msg *msg)
+{
+ const u8 *tx_buf = msg->tx_buf;
+ u8 *rx_buf = msg->rx_buf;
+ size_t i;
+ int ret, val;
+
+ dsi_write(dsi, DSI_PCKHDL_CFG, EN_CRC_RX | EN_ECC_RX | EN_BTA);
+ dsi_write(dsi, DSI_GEN_HDR, GEN_HDATA(tx_buf[0]) | GEN_HTYPE(msg->type));
+
+ ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
+ val, !(val & GEN_RD_CMD_BUSY), 1000,
+ CMD_PKT_STATUS_TIMEOUT_US);
+ if (ret < 0) {
+ dev_err(dsi->dev, "failed to read command response\n");
+ return ret;
+ }
+
+ for (i = 0; i < msg->rx_len;) {
+ u32 pld = dsi_read(dsi, DSI_GEN_PLD_DATA);
+ while (i < msg->rx_len) {
+ rx_buf[i] = pld & 0xff;
+ pld >>= 8;
+ i++;
+ }
+ }
+
+ return msg->rx_len;
+}
+
+static int dw_mipi_dsi_set_max_return_packet_size(struct dw_mipi_dsi *dsi,
+ size_t len)
+{
+ u8 val[] = { len & 0xff, (len >> 8) & 0xff };
+ struct mipi_dsi_msg msg = {
+ .channel = dsi->channel,
+ .type = MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE,
+ .tx_buf = val,
+ .tx_len = 2,
+ };
+
+ if (len > 0xffff)
+ return -EINVAL;
+
+ return dw_mipi_dsi_dcs_short_write(dsi, &msg);
+}
+
static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
const struct mipi_dsi_msg *msg)
{
@@ -693,6 +741,12 @@ static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
case MIPI_DSI_DCS_LONG_WRITE:
ret = dw_mipi_dsi_dcs_long_write(dsi, msg);
break;
+ case MIPI_DSI_DCS_READ:
+ ret = dw_mipi_dsi_set_max_return_packet_size(dsi, msg->rx_len);
+ if (ret < 0)
+ return ret;
+ ret = dw_mipi_dsi_dcs_read(dsi, msg);
+ break;
default:
dev_err(dsi->dev, "unsupported message type 0x%02x\n",
msg->type);
--
2.10.0.278.g4f427b1.dirty