drm/rockchip: dw-mipi-dsi: properly configure PHY timing

These values are specified as constant time periods but the PHY
configuration is in terms of the current lane byte clock so using
constant values guarantees that the timings will be outside the
specification with some display configurations.

Derive the necessary configuration from the byte clock in order to
ensure that the PHY configuration is correct.

Signed-off-by: John Keeping <john@metanate.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20170224125506.21533-17-john@metanate.com

diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
index 4fee5176c606ee3877a883159d4224120afdf4e4..9b6a60deb69ea40a7fb80a92ed91ec49f17711d2 100644 (file)
--- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
@@ -383,6 +383,22 @@ static void dw_mipi_dsi_phy_write(struct dw_mipi_dsi *dsi, u8 test_code,
        dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_TESTCLK | PHY_UNTESTCLR);
 }
 
+/**
+ * ns2bc - Nanoseconds to byte clock cycles
+ */
+static inline unsigned int ns2bc(struct dw_mipi_dsi *dsi, int ns)
+{
+       return DIV_ROUND_UP(ns * dsi->lane_mbps / 8, 1000);
+}
+
+/**
+ * ns2ui - Nanoseconds to UI time periods
+ */
+static inline unsigned int ns2ui(struct dw_mipi_dsi *dsi, int ns)
+{
+       return DIV_ROUND_UP(ns * dsi->lane_mbps, 1000);
+}
+
 static int dw_mipi_dsi_phy_init(struct dw_mipi_dsi *dsi)
 {
        int ret, testdin, vco, val;
@@ -434,10 +450,21 @@ static int dw_mipi_dsi_phy_init(struct dw_mipi_dsi *dsi)
                                         SETRD_MAX | POWER_MANAGE |
                                         TER_RESISTORS_ON);
 
-
-       dw_mipi_dsi_phy_write(dsi, 0x70, TLP_PROGRAM_EN | 0xf);
-       dw_mipi_dsi_phy_write(dsi, 0x71, THS_PRE_PROGRAM_EN | 0x55);
-       dw_mipi_dsi_phy_write(dsi, 0x72, THS_ZERO_PROGRAM_EN | 0xa);
+       dw_mipi_dsi_phy_write(dsi, 0x60, TLP_PROGRAM_EN | ns2bc(dsi, 500));
+       dw_mipi_dsi_phy_write(dsi, 0x61, THS_PRE_PROGRAM_EN | ns2ui(dsi, 40));
+       dw_mipi_dsi_phy_write(dsi, 0x62, THS_ZERO_PROGRAM_EN | ns2bc(dsi, 300));
+       dw_mipi_dsi_phy_write(dsi, 0x63, THS_PRE_PROGRAM_EN | ns2ui(dsi, 100));
+       dw_mipi_dsi_phy_write(dsi, 0x64, BIT(5) | ns2bc(dsi, 100));
+       dw_mipi_dsi_phy_write(dsi, 0x65, BIT(5) | (ns2bc(dsi, 60) + 7));
+
+       dw_mipi_dsi_phy_write(dsi, 0x70, TLP_PROGRAM_EN | ns2bc(dsi, 500));
+       dw_mipi_dsi_phy_write(dsi, 0x71,
+                             THS_PRE_PROGRAM_EN | (ns2ui(dsi, 50) + 5));
+       dw_mipi_dsi_phy_write(dsi, 0x72,
+                             THS_ZERO_PROGRAM_EN | (ns2bc(dsi, 140) + 2));
+       dw_mipi_dsi_phy_write(dsi, 0x73,
+                             THS_PRE_PROGRAM_EN | (ns2ui(dsi, 60) + 8));
+       dw_mipi_dsi_phy_write(dsi, 0x74, BIT(5) | ns2bc(dsi, 100));
 
        dsi_write(dsi, DSI_PHY_RSTZ, PHY_ENFORCEPLL | PHY_ENABLECLK |
                                     PHY_UNRSTZ | PHY_UNSHUTDOWNZ);