RE: [PATCH 09/17] drm: renesas: rz-du: mipi_dsi: Simplify HSFREQ calculation

Biju Das
2025-03-31T12:28:13Z

Hi Prabhakar,

Thanks for the patch.

> -----Original Message-----
> From: Prabhakar <prabhakar.csengg@gmail.com>
> Sent: 30 March 2025 22:07
> Subject: [PATCH 09/17] drm: renesas: rz-du: mipi_dsi: Simplify HSFREQ calculation
>
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
>
> Simplify the high-speed clock frequency (HSFREQ) calculation by removing the redundant multiplication
> and division by 8. The updated equation:
>
> hsfreq = (mode->clock * bpp) / (dsi->lanes);
>
> produces the same result while improving readability and clarity.
>
> Additionally, update the comment to clarify the relationship between HS clock bit frequency, HS byte
> clock frequency, and HSFREQ.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>

Cheers,
Biju

> ---
> drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c b/drivers/gpu/drm/renesas/rz-
> du/rzg2l_mipi_dsi.c
> index c6f60b7f203b..746f82442c01 100644
> --- a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> +++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> @@ -277,10 +277,10 @@ static int rzg2l_mipi_dsi_startup(struct rzg2l_mipi_dsi *dsi,
> * hsclk: DSI HS Byte clock frequency (Hz)
> * lanes: number of data lanes
> *
> - * hsclk(bit) = hsclk(byte) * 8
> + * hsclk(bit) = hsclk(byte) * 8 = hsfreq
> */
> bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);
> - hsfreq = (mode->clock * bpp * 8) / (8 * dsi->lanes);
> + hsfreq = (mode->clock * bpp) / dsi->lanes;
>
> ret = pm_runtime_resume_and_get(dsi->dev);
> if (ret < 0)
> --
> 2.49.0