drm/bridge: dw-mipi-dsi: permit configuring the escape clock rate

The Amlogic D-PHY in the Amlogic AXG SoC Family does support a frequency
higher than 10MHz for the TX Escape Clock, thus make the target rate
configurable.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Philippe Cornu <philippe.cornu@st.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200904125531.15248-1-narmstrong@baylibre.com

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
index 7e9a62a..6b268f9 100644 (file)
--- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
@@ -605,15 +605,30 @@ static void dw_mipi_dsi_disable(struct dw_mipi_dsi *dsi)
 
 static void dw_mipi_dsi_init(struct dw_mipi_dsi *dsi)
 {
+       const struct dw_mipi_dsi_phy_ops *phy_ops = dsi->plat_data->phy_ops;
+       unsigned int esc_rate; /* in MHz */
+       u32 esc_clk_division;
+       int ret;
+
        /*
         * The maximum permitted escape clock is 20MHz and it is derived from
-        * lanebyteclk, which is running at "lane_mbps / 8".  Thus we want:
-        *
-        *     (lane_mbps >> 3) / esc_clk_division < 20
+        * lanebyteclk, which is running at "lane_mbps / 8".
+        */
+       if (phy_ops->get_esc_clk_rate) {
+               ret = phy_ops->get_esc_clk_rate(dsi->plat_data->priv_data,
+                                               &esc_rate);
+               if (ret)
+                       DRM_DEBUG_DRIVER("Phy get_esc_clk_rate() failed\n");
+       } else
+               esc_rate = 20; /* Default to 20MHz */
+
+       /*
+        * We want :
+        *     (lane_mbps >> 3) / esc_clk_division < X
         * which is:
-        *     (lane_mbps >> 3) / 20 > esc_clk_division
+        *     (lane_mbps >> 3) / X > esc_clk_division
         */
-       u32 esc_clk_division = (dsi->lane_mbps >> 3) / 20 + 1;
+       esc_clk_division = (dsi->lane_mbps >> 3) / esc_rate + 1;
 
        dsi_write(dsi, DSI_PWR_UP, RESET);
 

diff --git a/include/drm/bridge/dw_mipi_dsi.h b/include/drm/bridge/dw_mipi_dsi.h
index b0e390b..bda8aa7 100644 (file)
--- a/include/drm/bridge/dw_mipi_dsi.h
+++ b/include/drm/bridge/dw_mipi_dsi.h
@@ -36,6 +36,7 @@ struct dw_mipi_dsi_phy_ops {
                             unsigned int *lane_mbps);
        int (*get_timing)(void *priv_data, unsigned int lane_mbps,
                          struct dw_mipi_dsi_dphy_timing *timing);
+       int (*get_esc_clk_rate)(void *priv_data, unsigned int *esc_clk_rate);
 };
 
 struct dw_mipi_dsi_host_ops {