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From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Fabrizio Castro <fabrizio.castro@bp.renesas.com>,
	Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>,
	Jacopo Mondi <jacopo+renesas@jmondi.org>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	DRI Development <dri-devel@lists.freedesktop.org>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Simon Horman <horms@verge.net.au>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Chris Paterson <Chris.Paterson2@renesas.com>,
	Biju Das <biju.das@bp.renesas.com>
Subject: Re: [PATCH/RFC 05/12] drm: rcar-du: lvds: Add data swap support
Date: Fri, 2 Aug 2019 11:01:30 +0200	[thread overview]
Message-ID: <CAMuHMdWw5SyP=jfwTpA=+qheTh1ckhiP_etn1J4PrRVdL4R1Pg@mail.gmail.com> (raw)
In-Reply-To: <20190802080613.GF5008@pendragon.ideasonboard.com>

Hi Laurent,

On Fri, Aug 2, 2019 at 10:06 AM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
> On Fri, Aug 02, 2019 at 08:34:02AM +0100, Fabrizio Castro wrote:
> > When in vertical stripe mode of operation, there is the option
> > of swapping even data and odd data on the two LVDS interfaces
> > used to drive the video output.
> > Add data swap support by exposing a new DT property named
> > "renesas,swap-data".
> >
> > Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>

> > --- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
> > +++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c

> > @@ -439,12 +440,16 @@ static void rcar_lvds_enable(struct drm_bridge *bridge)
> >       rcar_lvds_write(lvds, LVDCHCR, lvdhcr);
> >
> >       if (lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK) {
> > -             /*
> > -              * Configure vertical stripe based on the mode of operation of
> > -              * the connected device.
> > -              */
> > -             rcar_lvds_write(lvds, LVDSTRIPE,
> > -                             lvds->dual_link ? LVDSTRIPE_ST_ON : 0);
> > +             u32 lvdstripe = 0;
> > +
> > +             if (lvds->dual_link)
> > +                     /*
> > +                      * Configure vertical stripe based on the mode of
> > +                      * operation of the connected device.
> > +                      */
> > +                     lvdstripe = LVDSTRIPE_ST_ON | (lvds->stripe_swap_data ?
> > +                                                    LVDSTRIPE_ST_SWAP : 0);
>
> Would the following be simpler ?
>
>                 lvdstripe = (lvds->dual_link ? LVDSTRIPE_ST_ON : 0)
>                           | (lvds->stripe_swap_data ? LVDSTRIPE_ST_SWAP : 0);

From the point of view of "wc -l": yes.
From the point of view of readability, I'd go for:

    if (lvds->dual_link)
            lvdstripe |= LVDSTRIPE_ST_ON;
    if (lvds->stripe_swap_data)
            lvdstripe |= LVDSTRIPE_ST_SWAP;

> > +             rcar_lvds_write(lvds, LVDSTRIPE, lvdstripe);
> >       }
> >
> >       /*
> > @@ -770,8 +775,12 @@ static int rcar_lvds_parse_dt(struct rcar_lvds *lvds)

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

  reply	other threads:[~2019-08-02  9:01 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-02  7:33 [PATCH/RFC 00/12] Add dual-LVDS panel support to EK874 Fabrizio Castro
2019-08-02  7:33 ` [PATCH/RFC 01/12] dt-bindings: display: renesas: lvds: RZ/G2E needs renesas,companion too Fabrizio Castro
2019-08-02  7:48   ` Laurent Pinchart
2019-08-02  7:33 ` [PATCH/RFC 02/12] dt-bindings: display: renesas: lvds: Document renesas,swap-data Fabrizio Castro
2019-08-02  7:44   ` Laurent Pinchart
2019-08-05  8:59     ` Fabrizio Castro
2019-08-05  9:35       ` Laurent Pinchart
2019-08-05 10:07         ` Fabrizio Castro
2019-08-02  7:34 ` [PATCH/RFC 03/12] dt-bindings: panel: lvds: Add dual-link LVDS display support Fabrizio Castro
2019-08-02  8:00   ` Laurent Pinchart
2019-08-05  9:02     ` Fabrizio Castro
2019-08-02  7:34 ` [PATCH/RFC 04/12] dt-bindings: display: Add bindings for Advantech IDK-2121WR Fabrizio Castro
2019-08-02  8:03   ` Laurent Pinchart
2019-08-05  9:04     ` Fabrizio Castro
2019-08-02  7:34 ` [PATCH/RFC 05/12] drm: rcar-du: lvds: Add data swap support Fabrizio Castro
2019-08-02  8:06   ` Laurent Pinchart
2019-08-02  9:01     ` Geert Uytterhoeven [this message]
2019-08-05  9:32     ` Fabrizio Castro
2019-08-05 10:17       ` Laurent Pinchart
2019-08-02  7:34 ` [PATCH/RFC 06/12] drm: rcar-du: lvds: Do not look at ports for identifying bridges Fabrizio Castro
2019-08-02  8:08   ` Laurent Pinchart
2019-08-05  9:06     ` Fabrizio Castro
2019-08-02  7:34 ` [PATCH/RFC 07/12] drm: rcar-du: lvds: Add support for dual link panels Fabrizio Castro
2019-08-02  8:20   ` Laurent Pinchart
2019-08-05  9:12     ` Fabrizio Castro
2019-08-05  9:48       ` Laurent Pinchart
2019-08-05 10:07         ` Fabrizio Castro
2019-08-02  7:34 ` [PATCH/RFC 08/12] drm: rcar-du: lvds: Fix bridge_to_rcar_lvds Fabrizio Castro
2019-08-02  8:22   ` Laurent Pinchart
2019-08-05  9:13     ` Fabrizio Castro
2019-08-02  7:34 ` [PATCH/RFC 09/12] drm: rcar-du: lvds: Fix companion's mode Fabrizio Castro
2019-08-02  8:26   ` Laurent Pinchart
2019-08-05  9:15     ` Fabrizio Castro

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