drm/mediatek: Allow commands to be sent during video mode

[ Upstream commit 81cc7e51c4f1686b71e30046437056ece6b2cb4d ]

Mipi dsi panel drivers can use mipi_dsi_dcs_{set,get}_display_brightness()
to request backlight changes.

This can be done during panel initialization (dsi is in command mode)
or afterwards (dsi is in Video Mode).

When the DSI is in Video Mode, all commands are rejected.

Detect current DSI mode in mtk_dsi_host_transfer() and switch modes
temporarily to allow commands to be sent.

Signed-off-by: Julien STEPHAN <jstephan@baylibre.com>
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index f3978593499947686f954287c7f75014ae1f939d..9d54bb6aec30151307cf8a80cbbc5067a91d98c8 100644 (file)
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -910,24 +910,33 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
        u8 read_data[16];
        void *src_addr;
        u8 irq_flag = CMD_DONE_INT_FLAG;
+       u32 dsi_mode;
+       int ret;
 
-       if (readl(dsi->regs + DSI_MODE_CTRL) & MODE) {
-               DRM_ERROR("dsi engine is not command mode\n");
-               return -EINVAL;
+       dsi_mode = readl(dsi->regs + DSI_MODE_CTRL);
+       if (dsi_mode & MODE) {
+               mtk_dsi_stop(dsi);
+               ret = mtk_dsi_switch_to_cmd_mode(dsi, VM_DONE_INT_FLAG, 500);
+               if (ret)
+                       goto restore_dsi_mode;
        }
 
        if (MTK_DSI_HOST_IS_READ(msg->type))
                irq_flag |= LPRX_RD_RDY_INT_FLAG;
 
-       if (mtk_dsi_host_send_cmd(dsi, msg, irq_flag) < 0)
-               return -ETIME;
+       ret = mtk_dsi_host_send_cmd(dsi, msg, irq_flag);
+       if (ret)
+               goto restore_dsi_mode;
 
-       if (!MTK_DSI_HOST_IS_READ(msg->type))
-               return 0;
+       if (!MTK_DSI_HOST_IS_READ(msg->type)) {
+               recv_cnt = 0;
+               goto restore_dsi_mode;
+       }
 
        if (!msg->rx_buf) {
                DRM_ERROR("dsi receive buffer size may be NULL\n");
-               return -EINVAL;
+               ret = -EINVAL;
+               goto restore_dsi_mode;
        }
 
        for (i = 0; i < 16; i++)
@@ -952,7 +961,13 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
        DRM_INFO("dsi get %d byte data from the panel address(0x%x)\n",
                 recv_cnt, *((u8 *)(msg->tx_buf)));
 
-       return recv_cnt;
+restore_dsi_mode:
+       if (dsi_mode & MODE) {
+               mtk_dsi_set_mode(dsi);
+               mtk_dsi_start(dsi);
+       }
+
+       return ret < 0 ? ret : recv_cnt;
 }
 
 static const struct mipi_dsi_host_ops mtk_dsi_ops = {