drm/panel: himax-hx8394: set prepare_prev_first

Sending DSI commands from the prepare() callback requires DSI link to be
up at that point. For DSI hosts is guaranteed only if the panel driver
sets the .prepare_prev_first flag. Set it to let these panels work with
the DSI hosts which don't power on the link in their .mode_set callback.

Reviewed-by: Linus Walleij <linusw@kernel.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patch.msgid.link/20260413-waveshare-dsi-touch-v3-8-3aeb53022c32@oss.qualcomm.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

diff --git a/drivers/gpu/drm/panel/panel-himax-hx8394.c b/drivers/gpu/drm/panel/panel-himax-hx8394.c
index c4d3e09a228daa40ceae638b4ebac17941fc8222..d64f3521eb15b27161899d49914692e2e9da7531 100644 (file)
--- a/drivers/gpu/drm/panel/panel-himax-hx8394.c
+++ b/drivers/gpu/drm/panel/panel-himax-hx8394.c
@@ -792,6 +792,8 @@ static int hx8394_probe(struct mipi_dsi_device *dsi)
        if (ret)
                return ret;
 
+       ctx->panel.prepare_prev_first = true;
+
        drm_panel_add(&ctx->panel);
 
        ret = mipi_dsi_attach(dsi);