Clarify the meaning of the sub-fields in the crystal frequency and
transmitter interrupt debounce registers, with the only purpose of
increasing human readability.

Signed-off-by: AngeloGioacchino Del Regno 
<[email protected]>
---
 drivers/gpu/drm/mediatek/mtk_dp.c     | 35 ++++++++++++++++-----------
 drivers/gpu/drm/mediatek/mtk_dp_reg.h |  6 +++--
 2 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c 
b/drivers/gpu/drm/mediatek/mtk_dp.c
index 605ead7fa9bf..b861a5df9316 100644
--- a/drivers/gpu/drm/mediatek/mtk_dp.c
+++ b/drivers/gpu/drm/mediatek/mtk_dp.c
@@ -1204,9 +1204,15 @@ static void mtk_dp_initialize_settings_v2p1(struct 
mtk_dp *mtk_dp)
 
 static void mtk_dp_initialize_settings(struct mtk_dp *mtk_dp)
 {
+       /*
+        * Set DP XTAL freq to 26MHz and accumulator to 1.
+        * Valid values for XTAL freq are 12 and 26.
+        */
        mtk_dp_update_bits(mtk_dp, MTK_DP_TRANS_P0_342C,
-                          XTAL_FREQ_DP_TRANS_P0_DEFAULT,
-                          XTAL_FREQ_DP_TRANS_P0_MASK);
+                          FIELD_PREP_CONST(XTAL_FREQ_DP_ACCUM_NUM_MASK, 1) |
+                          FIELD_PREP_CONST(XTAL_FREQ_DP_CLOCK_MHZ_MASK, 26),
+                          XTAL_FREQ_DP_ACCUM_NUM_MASK | 
XTAL_FREQ_DP_CLOCK_MHZ_MASK);
+
        mtk_dp_update_bits(mtk_dp, MTK_DP_TRANS_P0_3540,
                           FEC_CLOCK_EN_MODE_DP_TRANS_P0,
                           FEC_CLOCK_EN_MODE_DP_TRANS_P0);
@@ -1248,28 +1254,29 @@ static void 
mtk_dp_initialize_aux_hpd_detect_settings(struct mtk_dp *mtk_dp)
 
 static void mtk_dp_initialize_hpd_detect_settings(struct mtk_dp *mtk_dp)
 {
-       u32 val;
-
        /* Mask AUX TOP interrupt, as this uses transmitter for HPD */
        mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_IRQ_MASK,
                           AUX_TOP_IRQ_MSK, AUX_TOP_IRQ_MSK);
 
-       /* Debounce threshold */
+       /* Set Hotplug debounce threshold time: xtal_period * deb_thd */
        mtk_dp_update_bits(mtk_dp, MTK_DP_TRANS_P0_3410,
                           8, HPD_DEB_THD_DP_TRANS_P0_MASK);
 
-       val = (HPD_INT_THD_DP_TRANS_P0_LOWER_500US |
-              HPD_INT_THD_DP_TRANS_P0_UPPER_1100US) << 4;
-       mtk_dp_update_bits(mtk_dp, MTK_DP_TRANS_P0_3410,
-                          val, HPD_INT_THD_DP_TRANS_P0_MASK);
-
        /*
-        * Connect threshold 1.5ms + 5 x 0.1ms = 2ms
-        * Disconnect threshold 1.5ms + 5 x 0.1ms = 2ms
+        * Set interrupt debounce threshold time
+        * VAL  |  0     1     2     3  INT_THD
+        * Low  | 100   300   500   700 uS
+        * High | 700   900  1100  1300 uS
         */
-       val = (5 << 8) | (5 << 12);
        mtk_dp_update_bits(mtk_dp, MTK_DP_TRANS_P0_3410,
-                          val,
+                          FIELD_PREP_CONST(HPD_INT_LOW_THD_DP_TRANS_P0_MASK, 
2) |
+                          FIELD_PREP_CONST(HPD_INT_HIGH_THD_DP_TRANS_P0_MASK, 
2),
+                          HPD_INT_THD_DP_TRANS_P0_MASK);
+
+       /* Connection and Disconnection thresholds: 1.5ms + (5 x 0.1) ms = 2ms 
*/
+       mtk_dp_update_bits(mtk_dp, MTK_DP_TRANS_P0_3410,
+                          FIELD_PREP_CONST(HPD_DISC_THD_DP_TRANS_P0_MASK, 5) |
+                          FIELD_PREP_CONST(HPD_CONN_THD_DP_TRANS_P0_MASK, 5),
                           HPD_DISC_THD_DP_TRANS_P0_MASK |
                           HPD_CONN_THD_DP_TRANS_P0_MASK);
        mtk_dp_update_bits(mtk_dp, MTK_DP_TRANS_P0_3430,
diff --git a/drivers/gpu/drm/mediatek/mtk_dp_reg.h 
b/drivers/gpu/drm/mediatek/mtk_dp_reg.h
index 9caf743f4fe6..418a2318c656 100644
--- a/drivers/gpu/drm/mediatek/mtk_dp_reg.h
+++ b/drivers/gpu/drm/mediatek/mtk_dp_reg.h
@@ -253,6 +253,8 @@
 #define MTK_DP_TRANS_P0_3410                           0x1410
 #define HPD_DEB_THD_DP_TRANS_P0_MASK                           GENMASK(3, 0)
 #define HPD_INT_THD_DP_TRANS_P0_MASK                           GENMASK(7, 4)
+#define HPD_INT_HIGH_THD_DP_TRANS_P0_MASK                      GENMASK(3, 2)
+#define HPD_INT_LOW_THD_DP_TRANS_P0_MASK                       GENMASK(1, 0)
 #define HPD_INT_THD_DP_TRANS_P0_LOWER_500US                    (2 << 4)
 #define HPD_INT_THD_DP_TRANS_P0_UPPER_1100US                   (2 << 6)
 #define HPD_DISC_THD_DP_TRANS_P0_MASK                          GENMASK(11, 8)
@@ -267,8 +269,8 @@
 #define IRQ_MASK_DP_TRANS_P0_INT_IRQ                           (BIT(3) << 4)
 #define IRQ_STATUS_DP_TRANS_P0_MASK                            GENMASK(15, 12)
 #define MTK_DP_TRANS_P0_342C                           0x142c
-#define XTAL_FREQ_DP_TRANS_P0_DEFAULT                          (BIT(0) | 
BIT(3) | BIT(5) | BIT(6))
-#define XTAL_FREQ_DP_TRANS_P0_MASK                             GENMASK(7, 0)
+#define XTAL_FREQ_DP_ACCUM_NUM_MASK                            GENMASK(1, 0)
+#define XTAL_FREQ_DP_CLOCK_MHZ_MASK                            GENMASK(7, 2)
 #define MTK_DP_TRANS_P0_3430                           0x1430
 #define HPD_INT_THD_ECO_DP_TRANS_P0_MASK                       GENMASK(1, 0)
 #define HPD_INT_THD_ECO_DP_TRANS_P0_HIGH_BOUND_EXT             BIT(1)
-- 
2.54.0

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