drm/imx: imx-ldb: enable DI clock in encoder_mode_set

Commit eb10d6355532 ("imx-drm: encoder prepare/mode_set must use adjusted mode")
broke the first LVDS modeset by using crtc->hwmode before crtc mode_set is
called. In fact, encoder prepare is not supposed to prepare the display clock
at all. Rather encoder mode_set should be used to set the DI clock rate, before
it is enabled by crtc commit.

Reported-by: Liu Ying <Ying.Liu@freescale.com>
Tested-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

1 files changed, 13 insertions, 15 deletions

diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
index 1b86aac0b341..2d6dc94e1e64 100644
--- a/drivers/gpu/drm/imx/imx-ldb.c
+++ b/drivers/gpu/drm/imx/imx-ldb.c
@@ -163,22 +163,7 @@ static void imx_ldb_encoder_prepare(struct drm_encoder *encoder)
 {
         struct imx_ldb_channel *imx_ldb_ch = enc_to_imx_ldb_ch(encoder);
         struct imx_ldb *ldb = imx_ldb_ch->ldb;
-        struct drm_display_mode *mode = &encoder->crtc->hwmode;
         u32 pixel_fmt;
-        unsigned long serial_clk;
-        unsigned long di_clk = mode->clock * 1000;
-        int mux = imx_drm_encoder_get_mux_id(imx_ldb_ch->child, encoder);
-
-        if (ldb->ldb_ctrl & LDB_SPLIT_MODE_EN) {
-                /* dual channel LVDS mode */
-                serial_clk = 3500UL * mode->clock;
-                imx_ldb_set_clock(ldb, mux, 0, serial_clk, di_clk);
-                imx_ldb_set_clock(ldb, mux, 1, serial_clk, di_clk);
-        } else {
-                serial_clk = 7000UL * mode->clock;
-                imx_ldb_set_clock(ldb, mux, imx_ldb_ch->chno, serial_clk,
-                                di_clk);
-        }
 
         switch (imx_ldb_ch->chno) {
         case 0:
@@ -247,6 +232,9 @@ static void imx_ldb_encoder_mode_set(struct drm_encoder *encoder,
         struct imx_ldb_channel *imx_ldb_ch = enc_to_imx_ldb_ch(encoder);
         struct imx_ldb *ldb = imx_ldb_ch->ldb;
         int dual = ldb->ldb_ctrl & LDB_SPLIT_MODE_EN;
+        unsigned long serial_clk;
+        unsigned long di_clk = mode->clock * 1000;
+        int mux = imx_drm_encoder_get_mux_id(imx_ldb_ch->child, encoder);
 
         if (mode->clock > 170000) {
                 dev_warn(ldb->dev,
@@ -257,6 +245,16 @@ static void imx_ldb_encoder_mode_set(struct drm_encoder *encoder,
                          "%s: mode exceeds 85 MHz pixel clock\n", __func__);
         }
 
+        if (dual) {
+                serial_clk = 3500UL * mode->clock;
+                imx_ldb_set_clock(ldb, mux, 0, serial_clk, di_clk);
+                imx_ldb_set_clock(ldb, mux, 1, serial_clk, di_clk);
+        } else {
+                serial_clk = 7000UL * mode->clock;
+                imx_ldb_set_clock(ldb, mux, imx_ldb_ch->chno, serial_clk,
+                                  di_clk);
+        }
+
         /* FIXME - assumes straight connections DI0 --> CH0, DI1 --> CH1 */
         if (imx_ldb_ch == &ldb->channel[0]) {
                 if (mode->flags & DRM_MODE_FLAG_NVSYNC)