drm/mgag200: Set/clear <syncrst> field in display enable/disable helpers

Modifying the <syncrst> field in mgag200_{enable,disable}_display()
makes the code more readable. Also clear the <asyncrst> field to enable
the display. The other bits in SEQ0 are unused, so no functional changes
are made.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200707082411.6583-6-tzimmermann@suse.de

diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c
index 05f8aa5..679eb5a 100644 (file)
--- a/drivers/gpu/drm/mgag200/mgag200_mode.c
+++ b/drivers/gpu/drm/mgag200/mgag200_mode.c
@@ -1284,7 +1284,12 @@ static void mgag200_g200ev_set_hiprilvl(struct mga_device *mdev)
 
 static void mgag200_enable_display(struct mga_device *mdev)
 {
-       u8 seq1, crtcext1;
+       u8 seq0, seq1, crtcext1;
+
+       RREG_SEQ(0x00, seq0);
+       seq0 |= MGAREG_SEQ0_SYNCRST |
+               MGAREG_SEQ0_ASYNCRST;
+       WREG_SEQ(0x00, seq0);
 
        /*
         * TODO: replace busy waiting with vblank IRQ; put
@@ -1307,7 +1312,11 @@ static void mgag200_enable_display(struct mga_device *mdev)
 
 static void mgag200_disable_display(struct mga_device *mdev)
 {
-       u8 seq1, crtcext1;
+       u8 seq0, seq1, crtcext1;
+
+       RREG_SEQ(0x00, seq0);
+       seq0 &= ~MGAREG_SEQ0_SYNCRST;
+       WREG_SEQ(0x00, seq0);
 
        /*
         * TODO: replace busy waiting with vblank IRQ; put
@@ -1338,9 +1347,6 @@ static void mga_crtc_prepare(struct drm_crtc *crtc)
        struct drm_device *dev = crtc->dev;
        struct mga_device *mdev = to_mga_device(dev);
 
-       /* start sync reset */
-       WREG_SEQ(0, 1);
-
        if (mdev->type == G200_WB || mdev->type == G200_EW3)
                mga_g200wb_prepare(crtc);
 }
@@ -1357,7 +1363,6 @@ static void mga_crtc_commit(struct drm_crtc *crtc)
        if (mdev->type == G200_WB || mdev->type == G200_EW3)
                mga_g200wb_commit(crtc);
 
-       WREG_SEQ(0, 0x3);
        mga_crtc_load_lut(crtc);
        mgag200_enable_display(mdev);
 }

diff --git a/drivers/gpu/drm/mgag200/mgag200_reg.h b/drivers/gpu/drm/mgag200/mgag200_reg.h
index 9f0be18..c3b7bca 100644 (file)
--- a/drivers/gpu/drm/mgag200/mgag200_reg.h
+++ b/drivers/gpu/drm/mgag200/mgag200_reg.h
@@ -236,6 +236,9 @@
 #define MGAREG_SEQ_INDEX       0x1fc4
 #define MGAREG_SEQ_DATA                0x1fc5
 
+#define MGAREG_SEQ0_ASYNCRST   BIT(0)
+#define MGAREG_SEQ0_SYNCRST    BIT(1)
+
 #define MGAREG_SEQ1_SCROFF     BIT(5)
 
 #define MGAREG_CRTC_INDEX      0x1fd4