[PATCH 2/2] video: dw-mipi-dsi: permit configuring the escape clock rate

[Neil Armstrong]

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.

This is based on the Linux commit [1] and adapted to the U-Boot driver.

Signed-off-by: Neil Armstrong <narmstr...@baylibre.com>

[1] a328ca7e4af3 ("drm/bridge: dw-mipi-dsi: permit configuring the escape clock 
rate")

Signed-off-by: Neil Armstrong <narmstr...@baylibre.com>
---
 drivers/video/dw_mipi_dsi.c | 20 ++++++++++++++++----
 include/mipi_dsi.h          |  1 +
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/drivers/video/dw_mipi_dsi.c b/drivers/video/dw_mipi_dsi.c
index 8f909a4e9f..12a55cfbec 100644
--- a/drivers/video/dw_mipi_dsi.c
+++ b/drivers/video/dw_mipi_dsi.c
@@ -483,15 +483,27 @@ static void dw_mipi_dsi_set_mode(struct dw_mipi_dsi *dsi,
 
 static void dw_mipi_dsi_init_pll(struct dw_mipi_dsi *dsi)
 {
+       const struct mipi_dsi_phy_ops *phy_ops = dsi->phy_ops;
+       unsigned int esc_rate;
+       u32 esc_clk_division;
+
        /*
         * The maximum permitted escape clock is 20MHz and it is derived from
-        * lanebyteclk, which is running at "lane_mbps / 8".  Thus we want:
+        * lanebyteclk, which is running at "lane_mbps / 8".
+        */
+       if (phy_ops->get_esc_clk_rate)
+               phy_ops->get_esc_clk_rate(dsi->device, &esc_rate);
+       else
+               esc_rate = 20; /* Default to 20MHz */
+
+       /*
+        * We want:
         *
-        *     (lane_mbps >> 3) / esc_clk_division < 20
+        *     (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/mipi_dsi.h b/include/mipi_dsi.h
index 55c7ab3328..4ca05f71e2 100644
--- a/include/mipi_dsi.h
+++ b/include/mipi_dsi.h
@@ -123,6 +123,7 @@ struct mipi_dsi_phy_ops {
        void (*post_set_mode)(void *priv_data,  unsigned long mode_flags);
        int (*get_timing)(void *priv_data, unsigned int lane_mbps,
                          struct mipi_dsi_phy_timing *timing);
+       void (*get_esc_clk_rate)(void *priv_data, unsigned int *esc_clk_rate);
 };
 
 /**
-- 
2.25.1