Hi,

with more and more patches for TC9595 support got meged into linux-next,
only a few remain on my patch stack.

This is one of them and is necessary for DP support:
Tested-by: Alexander Stein <[email protected]>

Am Dienstag, 25. Juni 2024, 14:26:10 CEST schrieb Marek Vasut:
> Initialize the bridge on attach already, to force lanes into LP11
> state, since attach does trigger attach of downstream bridges which
> may trigger (e)DP AUX channel mode read.
> 
> This fixes a corner case where DSIM with TC9595 attached to it fails
> to operate the DP AUX channel, because the TC9595 enters some debug
> mode when it is released from reset without lanes in LP11 mode. By
> ensuring the DSIM lanes are in LP11, the TC9595 (tc358767.c driver)
> can be reset in its attach callback called from DSIM attach callback,
> and recovered out of the debug mode just before TC9595 performs first
> AUX channel access later in its attach callback.
> 
> Signed-off-by: Marek Vasut <[email protected]>
> ---
> Cc: Adam Ford <[email protected]>
> Cc: Alexander Stein <[email protected]>
> Cc: Andrzej Hajda <[email protected]>
> Cc: Daniel Vetter <[email protected]>
> Cc: David Airlie <[email protected]>
> Cc: Frieder Schrempf <[email protected]>
> Cc: Inki Dae <[email protected]>
> Cc: Jagan Teki <[email protected]>
> Cc: Jernej Skrabec <[email protected]>
> Cc: Jonas Karlman <[email protected]>
> Cc: Laurent Pinchart <[email protected]>
> Cc: Lucas Stach <[email protected]>
> Cc: Maarten Lankhorst <[email protected]>
> Cc: Marek Szyprowski <[email protected]>
> Cc: Maxime Ripard <[email protected]>
> Cc: Michael Walle <[email protected]>
> Cc: Neil Armstrong <[email protected]>
> Cc: Robert Foss <[email protected]>
> Cc: Thomas Zimmermann <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> ---
> V2: Handle case where mode is not set yet
> ---
>  drivers/gpu/drm/bridge/samsung-dsim.c | 32 ++++++++++++++++++++-------
>  1 file changed, 24 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c 
> b/drivers/gpu/drm/bridge/samsung-dsim.c
> index e7e53a9e42afb..22d3bbd866d97 100644
> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> @@ -699,20 +699,24 @@ static unsigned long samsung_dsim_set_pll(struct 
> samsung_dsim *dsi,
>  
>  static int samsung_dsim_enable_clock(struct samsung_dsim *dsi)
>  {
> -     unsigned long hs_clk, byte_clk, esc_clk, pix_clk;
> +     unsigned long hs_clk, byte_clk, esc_clk;
>       unsigned long esc_div;
>       u32 reg;
>       struct drm_display_mode *m = &dsi->mode;
>       int bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);
>  
> -     /* m->clock is in KHz */
> -     pix_clk = m->clock * 1000;
> -
> -     /* Use burst_clk_rate if available, otherwise use the pix_clk */
> +     /*
> +      * Use burst_clk_rate if available, otherwise use the mode clock
> +      * if mode is already set and available, otherwise fall back to
> +      * PLL input clock and operate in 1:1 lowest frequency mode until
> +      * a mode is set.
> +      */
>       if (dsi->burst_clk_rate)
>               hs_clk = samsung_dsim_set_pll(dsi, dsi->burst_clk_rate);
> +     else if (m)     /* m->clock is in KHz */
> +             hs_clk = samsung_dsim_set_pll(dsi, DIV_ROUND_UP(m->clock * 1000 
> * bpp, dsi->lanes));
>       else
> -             hs_clk = samsung_dsim_set_pll(dsi, DIV_ROUND_UP(pix_clk * bpp, 
> dsi->lanes));
> +             hs_clk = dsi->pll_clk_rate;
>  
>       if (!hs_clk) {
>               dev_err(dsi->dev, "failed to configure DSI PLL\n");
> @@ -1643,9 +1647,21 @@ static int samsung_dsim_attach(struct drm_bridge 
> *bridge,
>                              enum drm_bridge_attach_flags flags)
>  {
>       struct samsung_dsim *dsi = bridge_to_dsi(bridge);
> +     int ret;
>  
> -     return drm_bridge_attach(bridge->encoder, dsi->out_bridge, bridge,
> -                              flags);
> +     ret = pm_runtime_resume_and_get(dsi->dev);
> +     if (ret < 0)
> +             return ret;
> +
> +     ret = samsung_dsim_init(dsi);
> +     if (ret < 0)
> +             goto err;
> +
> +     ret = drm_bridge_attach(bridge->encoder, dsi->out_bridge, bridge,
> +                             flags);
> +err:
> +     pm_runtime_put_sync(dsi->dev);
> +     return ret;
>  }
>  
>  static const struct drm_bridge_funcs samsung_dsim_bridge_funcs = {
> 


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