On Mon, 02 Jan 2017, Madhav Chauhan <madhav.chau...@intel.com> wrote:
> From: Deepak M <m.dee...@intel.com>
>
> For GEMINILAKE, dphy param reg values are programmed in terms
> of HS byte clock count while for legacy platforms in terms of
> HS ddr clk count.

No need to call everything before this one "legacy".

> Signed-off-by: Deepak M <m.dee...@intel.com>
> Signed-off-by: Madhav Chauhan <madhav.chau...@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_dsi_panel_vbt.c | 33 
> +++++++++++++++++++++++-------
>  1 file changed, 26 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c 
> b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
> index 8f683b8..8059cbb 100644
> --- a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
> +++ b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
> @@ -695,16 +695,26 @@ struct drm_panel *vbt_panel_init(struct intel_dsi 
> *intel_dsi, u16 panel_id)
>       /* count values in UI = (ns value) * (bitrate / (2 * 10^6))
>        *
>        * Since txddrclkhs_i is 2xUI, all the count values programmed in
> -      * DPHY param register are divided by 2
> +      * DPHY param register are divided by 2 except GEMINILAKE where it is
> +      * programmed in terms of HS byte clock so divided by 8

Would you say these two hold?

1) HSDDR = 2 * HS

2) HS byte clock = HS / 8

So it would seem to me either the existing code or your patch is
wrong. (Or I'm seriously confused.)

If the register is in terms of clock *cycles*, not frequency, should the
HSDDR based clock (pre-GLK) actually have *twice* the clock cycles, not
*half*? Making the existing code wrong?

The existing code could use some serious cleanup to make it readable. :(

BR,
Jani.



>        *
>        * prepare count
>        */
>       ths_prepare_ns = max(mipi_config->ths_prepare,
>                            mipi_config->tclk_prepare);
> -     prepare_cnt = DIV_ROUND_UP(ths_prepare_ns * ui_den, ui_num * 2);
> +     if (IS_GEMINILAKE(dev_priv))
> +             prepare_cnt = DIV_ROUND_UP(ths_prepare_ns * ui_den, ui_num * 8);
> +     else
> +             prepare_cnt = DIV_ROUND_UP(ths_prepare_ns * ui_den, ui_num * 2);
>  
>       /* exit zero count */
> -     exit_zero_cnt = DIV_ROUND_UP(
> +     if (IS_GEMINILAKE(dev_priv))
> +             exit_zero_cnt = DIV_ROUND_UP(
> +                             (ths_prepare_hszero - ths_prepare_ns) * ui_den,
> +                             ui_num * 8
> +                             );
> +     else
> +             exit_zero_cnt = DIV_ROUND_UP(
>                               (ths_prepare_hszero - ths_prepare_ns) * ui_den,
>                               ui_num * 2
>                               );
> @@ -719,13 +729,22 @@ struct drm_panel *vbt_panel_init(struct intel_dsi 
> *intel_dsi, u16 panel_id)
>               exit_zero_cnt += 1;
>  
>       /* clk zero count */
> -     clk_zero_cnt = DIV_ROUND_UP(
> -                     (tclk_prepare_clkzero - ths_prepare_ns)
> -                     * ui_den, 2 * ui_num);
> +     if (IS_GEMINILAKE(dev_priv))
> +             clk_zero_cnt = DIV_ROUND_UP(
> +                             (tclk_prepare_clkzero - ths_prepare_ns)
> +                             * ui_den, 8 * ui_num);
> +     else
> +             clk_zero_cnt = DIV_ROUND_UP(
> +                             (tclk_prepare_clkzero - ths_prepare_ns)
> +                             * ui_den, 2 * ui_num);
>  
>       /* trail count */
>       tclk_trail_ns = max(mipi_config->tclk_trail, mipi_config->ths_trail);
> -     trail_cnt = DIV_ROUND_UP(tclk_trail_ns * ui_den, 2 * ui_num);
> +
> +     if (IS_GEMINILAKE(dev_priv))
> +             trail_cnt = DIV_ROUND_UP(tclk_trail_ns * ui_den, 8 * ui_num);
> +     else
> +             trail_cnt = DIV_ROUND_UP(tclk_trail_ns * ui_den, 2 * ui_num);
>  
>       if (prepare_cnt > PREPARE_CNT_MAX ||
>               exit_zero_cnt > EXIT_ZERO_CNT_MAX ||

-- 
Jani Nikula, Intel Open Source Technology Center
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