drm/bridge: tc358768: Disable non-continuous clock mode

[ Upstream commit fbc5a90e82c1131869e76ce5b082693b8a75c121 ]

Non-continuous clock mode doesn't work because driver doesn't support it
properly. The bridge driver programs wrong bitfields that are required by
the non-continuous mode (BTACNTRL1 register bitfields are swapped in the
code), but fixing them doesn't help.

Display panel of ASUS Transformer TF700T tablet supports non-continuous
mode and display doesn't work at all using that mode. There are no
device-trees that are actively using this DSI bridge in upstream yet,
so clearly the broken mode wasn't ever tested properly. It's a bit too
difficult to get LP mode working, hence let's disable the offending mode
for now and fall back to continuous mode.

Tested-by: Andreas Westman Dorcsak <hedmoo@yahoo.com> # Asus TF700T
Tested-by: Maxim Schwalm <maxim.schwalm@gmail.com> #TF700T
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211002233447.1105-5-digetx@gmail.com
Stable-dep-of: 66962d5c3c51 ("drm/bridge: tc358768: Fix bit updates")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index da37dfd81a6fb47bee4c29f9fe849ba35d4a3d4a..1e5304274ce2084b7ae30e11711bab5e5451a1d5 100644 (file)
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -637,6 +637,7 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 {
        struct tc358768_priv *priv = bridge_to_tc358768(bridge);
        struct mipi_dsi_device *dsi_dev = priv->output.dev;
+       unsigned long mode_flags = dsi_dev->mode_flags;
        u32 val, val2, lptxcnt, hact, data_type;
        s32 raw_val;
        const struct drm_display_mode *mode;
@@ -644,6 +645,11 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
        u32 dsiclk, dsibclk;
        int ret, i;
 
+       if (mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS) {
+               dev_warn_once(priv->dev, "Non-continuous mode unimplemented, falling back to continuous\n");
+               mode_flags &= ~MIPI_DSI_CLOCK_NON_CONTINUOUS;
+       }
+
        tc358768_hw_enable(priv);
 
        ret = tc358768_sw_reset(priv);
@@ -779,7 +785,7 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
                val |= BIT(i + 1);
        tc358768_write(priv, TC358768_HSTXVREGEN, val);
 
-       if (!(dsi_dev->mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
+       if (!(mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
                tc358768_write(priv, TC358768_TXOPTIONCNTRL, 0x1);
 
        /* TXTAGOCNT[26:16] RXTASURECNT[10:0] */
@@ -836,7 +842,7 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 
        val |= TC358768_DSI_CONTROL_TXMD;
 
-       if (!(dsi_dev->mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
+       if (!(mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
                val |= TC358768_DSI_CONTROL_HSCKMD;
 
        if (dsi_dev->mode_flags & MIPI_DSI_MODE_NO_EOT_PACKET)