Re: [PATCH v2 7/7] drm: rcar-du: dsi: Add r8a779g0 support

From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Biju Das <biju.das.jz@bp.renesas.com>
Cc: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Magnus Damm <magnus.damm@gmail.com>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>,
	"linux-renesas-soc@vger.kernel.org" 
	<linux-renesas-soc@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Andrzej Hajda <andrzej.hajda@intel.com>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Robert Foss <robert.foss@linaro.org>,
	Jonas Karlman <jonas@kwiboo.se>,
	Jernej Skrabec <jernej.skrabec@gmail.com>
Subject: Re: [PATCH v2 7/7] drm: rcar-du: dsi: Add r8a779g0 support
Date: Tue, 29 Nov 2022 12:49:27 +0100	[thread overview]
Message-ID: <CAMuHMdXz8ZSge5b4s8v6Oon55gO+3Cu_Uvn7GFV62JCSqNf1Qw@mail.gmail.com> (raw)
In-Reply-To: <OS0PR01MB59224C2B4F889534922ACFE186129@OS0PR01MB5922.jpnprd01.prod.outlook.com>

Hi Biju,

On Tue, Nov 29, 2022 at 12:40 PM Biju Das <biju.das.jz@bp.renesas.com> wrote:
> > From: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
> > On 29/11/2022 03:49, Laurent Pinchart wrote:
> > > On Wed, Nov 23, 2022 at 08:59:46AM +0200, Tomi Valkeinen wrote:
> > >> Add DSI support for r8a779g0. The main differences to r8a779a0 are in
> > >> the PLL and PHTW setups.
> > >>
> > >> Signed-off-by: Tomi Valkeinen
> > >> <tomi.valkeinen+renesas@ideasonboard.com>

> > >> --- a/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c
> > >> +++ b/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c
> > >> @@ -9,6 +9,7 @@
> > >>   #include <linux/delay.h>
> > >>   #include <linux/io.h>
> > >>   #include <linux/iopoll.h>
> > >> +#include <linux/math64.h>
> > >>   #include <linux/module.h>
> > >>   #include <linux/of.h>
> > >>   #include <linux/of_device.h>
> > >> @@ -28,6 +29,20 @@
> > >>   #include "rcar_mipi_dsi.h"
> > >>   #include "rcar_mipi_dsi_regs.h"
> > >>
> > >> +#define MHZ(v) ((v) * 1000000u)
> > >
> > > Isn't the U suffix usually spelled in uppercase ? Same below.
> >
> > I couldn't find any coding style guidelines on that. I like the lower
> > case visually. The suffix stands out much clearer on 10000000u than on
> > 10000000U. But I can change it if you feel otherwise.
>
> https://elixir.bootlin.com/linux/v6.1-rc7/source/include/linux/units.h#L11
>
> Maybe you could add MHZ here??

Or use the existing MEGA? The metric system is soooo nice! ;-)

BTW, looks like the people adding definitions like

    #define MICROHZ_PER_HZ 1000000UL
    #define MILLIHZ_PER_HZ 1000UL

    #define MILLIWATT_PER_WATT 1000UL
    #define MICROWATT_PER_MILLIWATT 1000UL
    #define MICROWATT_PER_WATT 1000000UL

didn't grasp the full power...

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