linux-kernel - Re: [PATCH 4/9] drm/rcar-du: dsi: Fix PHY lock bit check

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Message-ID: <20241203084824.GG10736@pendragon.ideasonboard.com>
Date: Tue, 3 Dec 2024 10:48:24 +0200
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
Cc: Kieran Bingham <kieran.bingham+renesas@...asonboard.com>,
	Andrzej Hajda <andrzej.hajda@...el.com>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Robert Foss <rfoss@...nel.org>, Jonas Karlman <jonas@...boo.se>,
	Jernej Skrabec <jernej.skrabec@...il.com>,
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	Magnus Damm <magnus.damm@...il.com>,
	Michael Turquette <mturquette@...libre.com>,
	Stephen Boyd <sboyd@...nel.org>, LUU HOAI <hoai.luu.ub@...esas.com>,
	Jagan Teki <jagan@...rulasolutions.com>,
	Sam Ravnborg <sam@...nborg.org>,
	Biju Das <biju.das.jz@...renesas.com>,
	dri-devel@...ts.freedesktop.org, linux-renesas-soc@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-clk@...r.kernel.org,
	Tomi Valkeinen <tomi.valkeinen+renesas@...asonboard.com>
Subject: Re: [PATCH 4/9] drm/rcar-du: dsi: Fix PHY lock bit check

Hi Tomi,

Thank you for the patch.

On Tue, Dec 03, 2024 at 10:01:38AM +0200, Tomi Valkeinen wrote:
> From: Tomi Valkeinen <tomi.valkeinen+renesas@...asonboard.com>
> 
> The driver checks for bit 16 (using CLOCKSET1_LOCK define) in CLOCKSET1
> register when waiting for the PPI clock. However, the right bit to check
> is bit 17 (CLOCKSET1_LOCK_PHY define). Not only that, but there's
> nothing in the documents for bit 16 for V3U nor V4H.
> 
> So, fix the check to use bit 17, and drop the define for bit 16.
> 
> Fixes: 155358310f01 ("drm: rcar-du: Add R-Car DSI driver")
> Fixes: 11696c5e8924 ("drm: Place Renesas drivers in a separate dir")

Should this have CC: stable ?

> Signed-off-by: Tomi Valkeiben <tomi.valkeinen+renesas@...asonboard.com>

Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>

> ---
>  drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c      | 2 +-
>  drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi_regs.h | 1 -
>  2 files changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c b/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
> index 2dba7c5ffd2c..92f4261305bd 100644
> --- a/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
> +++ b/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
> @@ -587,7 +587,7 @@ static int rcar_mipi_dsi_startup(struct rcar_mipi_dsi *dsi,
>  	for (timeout = 10; timeout > 0; --timeout) {
>  		if ((rcar_mipi_dsi_read(dsi, PPICLSR) & PPICLSR_STPST) &&
>  		    (rcar_mipi_dsi_read(dsi, PPIDLSR) & PPIDLSR_STPST) &&
> -		    (rcar_mipi_dsi_read(dsi, CLOCKSET1) & CLOCKSET1_LOCK))
> +		    (rcar_mipi_dsi_read(dsi, CLOCKSET1) & CLOCKSET1_LOCK_PHY))
>  			break;
>  
>  		usleep_range(1000, 2000);
> diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi_regs.h b/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi_regs.h
> index f8114d11f2d1..a6b276f1d6ee 100644
> --- a/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi_regs.h
> +++ b/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi_regs.h
> @@ -142,7 +142,6 @@
>  
>  #define CLOCKSET1			0x101c
>  #define CLOCKSET1_LOCK_PHY		(1 << 17)
> -#define CLOCKSET1_LOCK			(1 << 16)
>  #define CLOCKSET1_CLKSEL		(1 << 8)
>  #define CLOCKSET1_CLKINSEL_EXTAL	(0 << 2)
>  #define CLOCKSET1_CLKINSEL_DIG		(1 << 2)

-- 
Regards,

Laurent Pinchart