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

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Message-ID: <7f821dc9-299f-4e7e-b6dd-568573358300@kernel.org>
Date: Fri, 4 Oct 2024 12:45:08 +0300
From: Roger Quadros <rogerq@...nel.org>
To: Andreas Kemnade <andreas@...nade.info>
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



On 04/10/2024 12:01, Andreas Kemnade wrote:
> 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.

OK. you could then leave it as it is now.

> 
>>>  	};
>>>  
>>>  	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

-- 
cheers,
-roger