Re: [PATCH v2 1/2] dt-bindings: gpio: Add gpio-line-names to STMPE GPIO

[Alexander Stein <alexander.stein@ew.tq-group.com>]

Am Montag, 24. Juli 2023, 11:54:12 CEST schrieb Krzysztof Kozlowski:
> On 24/07/2023 09:58, Alexander Stein wrote:
> > Hi,
> > 
> > Am Montag, 24. Juli 2023, 09:23:09 CEST schrieb Krzysztof Kozlowski:
> >> On 24/07/2023 08:35, Alexander Stein wrote:
> >>> This is a gpio-controller, so gpio-line-names should be allowed as well.
> >>> stmpe2403 supports up to 24 GPIOs.
> >>> 
> >>> Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
> >>> ---
> >>> Changes in v2:
> >>> * Add min/maxItems
> >>> 
> >>>  Documentation/devicetree/bindings/gpio/st,stmpe-gpio.yaml | 4 ++++
> >>>  1 file changed, 4 insertions(+)
> >>> 
> >>> diff --git a/Documentation/devicetree/bindings/gpio/st,stmpe-gpio.yaml
> >>> b/Documentation/devicetree/bindings/gpio/st,stmpe-gpio.yaml index
> >>> 22c0cae73425..4555f1644a4d 100644
> >>> --- a/Documentation/devicetree/bindings/gpio/st,stmpe-gpio.yaml
> >>> +++ b/Documentation/devicetree/bindings/gpio/st,stmpe-gpio.yaml
> >>> 
> >>> @@ -28,6 +28,10 @@ properties:
> >>>    gpio-controller: true
> >>> 
> >>> +  gpio-line-names:
> >>> +    minItems: 1
> >>> +    maxItems: 24
> >>> +
> >> 
> >> I am sure there is no variant with one GPIO.
> > 
> > That's true. But if only one GPIO is actually connected there is no use
> > enforcing to add empty entries.
> > AFAIK it is also allowed to provide an incomplete array.
> 
> Did you test it? Linux prints warning. Warning means "not allowed".

I did and I don't see any warnings.
I using the following (modified) GPIO subnode on an stmpe811 chip:
gpio {
	compatible = "st,stmpe-gpio";
	gpio-controller;
	#gpio-cells = <2>;
	interrupt-controller;
	#interrupt-cells = <2>;
	/* GPIO 5-7 used for touch */
	st,norequest-mask = <0xf0>;
	gpio-line-names = "GPIO_ADC_I2C1_1";
};

I only see the warning "stmpe-gpio stmpe-gpio: DMA mask not set", but that's a 
different matter.
Only GPIO 0-3 are connected. Original property is
gpio-line-names = "GPIO_ADC_I2C1_1",
	        "GPIO_ADC_I2C1_2",
	        "GPIO_ADC_I2C1_3",
	        "GPIO_ADC_I2C1_4";

Also gpioinfo shows that the gpiochip has 8 pins while only the first one is 
named.

gpiochip7 - 8 lines:
        line   0: "GPIO_ADC_I2C1_1" unused input active-high 
        line   1:      unnamed       unused   input  active-high 
        line   2:      unnamed       unused   input  active-high 
        line   3:      unnamed       unused   input  active-high 
        line   4:      unnamed       unused   input  active-high 
        line   5:      unnamed       unused   input  active-high 
        line   6:      unnamed       unused   input  active-high 
        line   7:      unnamed       unused   input  active-high


If 4 GPIOs are named the output shows names for lines 1-3 accordingly, but no 
errors/warnings as well.

> The expectation is that the rest are named "NC".

Where does this expectation come from? Is there any pending change I am not 
aware of?

Best regards,
Alexander

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