linux-kernel - Re: [PATCH 2/4] ARM: dts: omap: omap4-epson-embt2ws: wire up regulators

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Message-ID: <20241004110110.163db244@akair>
Date: Fri, 4 Oct 2024 11:01:10 +0200
From: Andreas Kemnade <andreas@...nade.info>
To: Roger Quadros <rogerq@...nel.org>
Cc: Conor Dooley <conor+dt@...nel.org>, Krzysztof Kozlowski
 <krzk+dt@...nel.org>, linux-kernel@...r.kernel.org, Rob Herring
 <robh@...nel.org>, khilman@...libre.com, devicetree@...r.kernel.org,
 tony@...mide.com, aaro.koskinen@....fi, linux-omap@...r.kernel.org
Subject: Re: [PATCH 2/4] ARM: dts: omap: omap4-epson-embt2ws: wire up
 regulators

Am Fri, 4 Oct 2024 10:38:22 +0300
schrieb Roger Quadros <rogerq@...nel.org>:

> On 01/10/2024 00:30, Andreas Kemnade wrote:
> > Wire up the regulators where usage is plausible. Do not
> > wire them if purpose/usage is unclear like 5V for
> > many things requiring lower voltages.
> > 
> > Signed-off-by: Andreas Kemnade <andreas@...nade.info>
> > ---
> >  arch/arm/boot/dts/ti/omap/omap4-epson-embt2ws.dts | 11 ++++-------
> >  1 file changed, 4 insertions(+), 7 deletions(-)
> > 
> > diff --git a/arch/arm/boot/dts/ti/omap/omap4-epson-embt2ws.dts
> > b/arch/arm/boot/dts/ti/omap/omap4-epson-embt2ws.dts index
> > d6b0abba19f6..cc1b6080bf95 100644 ---
> > a/arch/arm/boot/dts/ti/omap/omap4-epson-embt2ws.dts +++
> > b/arch/arm/boot/dts/ti/omap/omap4-epson-embt2ws.dts @@ -20,13
> > +20,13 @@ memory@...00000 { backlight-left {
> >  		compatible = "pwm-backlight";
> >  		pwms = <&twl_pwm 1 7812500>;
> > -		power-supply = <&unknown_supply>;
> > +		power-supply = <&lb_v50>;  
> 
> This is probably wrong. I noticed this while reviewing patch 3.
> 
> you probably want to wire this to blc_l?
> 
No idea was blc_l is. I did not find any code handling blc_l.
looking at the vendor kernel:

$ grep -R BLC_L_GPIO *
arch/arm/mach-omap2/board-bt2ws.c:#define BLC_L_GPIO
16	/* LB LED GPIO */ arch/arm/mach-omap2/board-bt2ws.c:
{BLC_L_GPIO,   GPIOF_OUT_INIT_LOW,  "gpio_blc_l"   },
arch/arm/mach-omap2/board-bt2ws.c:	gpio_export(BLC_L_GPIO, 0);
arch/arm/mach-omap2/board-bt2ts.c:#define BLC_L_GPIO
16	/* LB LED GPIO */ arch/arm/mach-omap2/board-bt2ts.c:
{BLC_L_GPIO,   GPIOF_OUT_INIT_LOW,  "gpio_blc_l"   },
arch/arm/mach-omap2/board-bt2ts.c:	gpio_export(BLC_L_GPIO, 0);

These two gpios are exported. But they seem not to influence
backlight in any way. I just tested again to make sure. Maybe it is just
a leftover from earlier board revisions.

> >  	};
> >  
> >  	backlight-right {
> >  		compatible = "pwm-backlight";
> >  		pwms = <&twl_pwm 0 7812500>;
> > -		power-supply = <&unknown_supply>;
> > +		power-supply = <&lb_v50>;  
> 
> this one should be wired to blc_r?
>
Same as with blc_l.
$ grep -R BLC_R_GPIO *
arch/arm/mach-omap2/board-bt2ws.c:#define BLC_R_GPIO
17	/* LB LED GPIO */ arch/arm/mach-omap2/board-bt2ws.c:
{BLC_R_GPIO,   GPIOF_OUT_INIT_LOW,  "gpio_blc_r"   },
arch/arm/mach-omap2/board-bt2ws.c:	gpio_export(BLC_R_GPIO, 0);
arch/arm/mach-omap2/board-bt2ts.c:#define BLC_R_GPIO
17	/* LB LED GPIO */ arch/arm/mach-omap2/board-bt2ts.c:
{BLC_R_GPIO,   GPIOF_OUT_INIT_LOW,  "gpio_blc_r"   },
arch/arm/mach-omap2/board-bt2ts.c:	gpio_export(BLC_R_GPIO, 0);

Regards,
Andreas