Patch "drm/bridge: tc358768: fix PLL target frequency" has been added to the 6.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    drm/bridge: tc358768: fix PLL target frequency

to the 6.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-bridge-tc358768-fix-pll-target-frequency.patch
and it can be found in the queue-6.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 8bb4b7626d5a47d6023bb880b55859b13d0178fa
Author: Francesco Dolcini <francesco.dolcini@xxxxxxxxxxx>
Date:   Thu Apr 27 16:29:28 2023 +0200

    drm/bridge: tc358768: fix PLL target frequency
    
    [ Upstream commit ffd2e4bbea626d565b9817312b0fcfb382fecb88 ]
    
    Correctly compute the PLL target frequency, the current formula works
    correctly only when the input bus width is 24bit, actually to properly
    compute the PLL target frequency what is relevant is the bits-per-pixel
    on the DSI link.
    
    No regression expected since the DSI format is currently hard-coded as
    MIPI_DSI_FMT_RGB888.
    
    Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver")
    Signed-off-by: Francesco Dolcini <francesco.dolcini@xxxxxxxxxxx>
    Reviewed-by: Robert Foss <rfoss@xxxxxxxxxx>
    Signed-off-by: Robert Foss <rfoss@xxxxxxxxxx>
    Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-4-francesco@xxxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index e9e3f9e02bba0..dba1bf3912f1e 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -146,6 +146,7 @@ struct tc358768_priv {
 
 	u32 pd_lines; /* number of Parallel Port Input Data Lines */
 	u32 dsi_lanes; /* number of DSI Lanes */
+	u32 dsi_bpp; /* number of Bits Per Pixel over DSI */
 
 	/* Parameters for PLL programming */
 	u32 fbd;	/* PLL feedback divider */
@@ -284,12 +285,12 @@ static void tc358768_hw_disable(struct tc358768_priv *priv)
 
 static u32 tc358768_pll_to_pclk(struct tc358768_priv *priv, u32 pll_clk)
 {
-	return (u32)div_u64((u64)pll_clk * priv->dsi_lanes, priv->pd_lines);
+	return (u32)div_u64((u64)pll_clk * priv->dsi_lanes, priv->dsi_bpp);
 }
 
 static u32 tc358768_pclk_to_pll(struct tc358768_priv *priv, u32 pclk)
 {
-	return (u32)div_u64((u64)pclk * priv->pd_lines, priv->dsi_lanes);
+	return (u32)div_u64((u64)pclk * priv->dsi_bpp, priv->dsi_lanes);
 }
 
 static int tc358768_calc_pll(struct tc358768_priv *priv,
@@ -426,6 +427,7 @@ static int tc358768_dsi_host_attach(struct mipi_dsi_host *host,
 	priv->output.panel = panel;
 
 	priv->dsi_lanes = dev->lanes;
+	priv->dsi_bpp = mipi_dsi_pixel_format_to_bpp(dev->format);
 
 	/* get input ep (port0/endpoint0) */
 	ret = -EINVAL;
@@ -437,7 +439,7 @@ static int tc358768_dsi_host_attach(struct mipi_dsi_host *host,
 	}
 
 	if (ret)
-		priv->pd_lines = mipi_dsi_pixel_format_to_bpp(dev->format);
+		priv->pd_lines = priv->dsi_bpp;
 
 	drm_bridge_add(&priv->bridge);