Re: [PATCH] arm64: dts: qcom: sdm845-lg: Enable NFC

[Paul Sajna]

On 2026-09-06 11:13 a.m., Paul Sajna wrote:
> On 2026-09-03 1:10 a.m., Konrad Dybcio wrote:
> > On 9/3/26 4:03 AM, Paul Sajna wrote:
> > > Add the i2c and tlmm nodes to support the NXP PN547 NFC chip
> > >
> > > Downstream dtsi for reference:
> > > https://github.com/LineageOS/android_kernel_lge_sdm845/blob/ 
> > > lineage-22.2/arch/arm64/boot/dts/lge/sdm845-judy/sdm845- 
> > > judyln_lao_com/sdm845-judyln_lao_com-nfc.dtsi
> > >
> > > Signed-off-by: Paul Sajna <sajattack@xxxxxxxxxxxxxxxx>
> > > ---
> >
> > [...]
> >
> > > +    nfc_default: nfc-default-state {
> > > +        pins = "gpio12", "gpio62", "gpio63";
> > > +        function = "gpio";
> > > +        drive-strength = <6>;
> > > +        bias-pull-up;
> >
> > active-high pins and pull-ups don't really go well together, please
> > verify that
> >
> > Konrad
>
> Downstream decompile sez
>
> nfc {
>
>                  nfc_int_active {
>                      phandle = <0x46a>;
>
>                      config {
>                          pins = "gpio63";
>                          drive-strength = <0x02>;
>                          bias-pull-up;
>                      };
>
>                      mux {
>                          pins = "gpio63";
>                          function = "gpio";
>                      };
>                  };
>
>                  nfc_enable_suspend {
>                      phandle = <0x46d>;
>
>                      config {
>                          pins = "gpio12", "gpio62", "gpio116";
>                          bias-disable;
>                          drive-strength = <0x02>;
>                      };
>
>                      mux {
>                          pins = "gpio12", "gpio62", "gpio116";
>                          function = "gpio";
>                      };
>                  };
>
>                  nfc_enable_active {
>                      phandle = <0x46c>;
>
>                      config {
>                          pins = "gpio12", "gpio62", "gpio116";
>                          drive-strength = <0x02>;
>                          bias-pull-up;
>                      };
>
>                      mux {
>                          pins = "gpio12", "gpio62", "gpio116";
>                          function = "gpio";
>                      };
>                  };
>
>                  nfc_int_suspend {
>                      phandle = <0x46b>;
>
>                      config {
>                          pins = "gpio63";
>                          drive-strength = <0x02>;
>                          bias-pull-up;
>                      };
>
>                      mux {
>                          pins = "gpio63";
>                          function = "gpio";
>                      };
>                  };
>              };

Also active high (0x00)

pn547@28 {
	compatible = "nxp,pn547";
	nxp,i2c-pull-up = <0x01>;
	nxp,gpio_irq = <0x34 0x3f 0x00>;
	nxp,gpio_ven = <0x34 0x0c 0x00>;
	nxp,gpio_mode = <0x34 0x3e 0x00>;
	nxp,gpio_scl = <0x34 0x2a 0x00>;
	nxp,gpio_sda = <0x34 0x29 0x00>;
	status = "ok";
	interrupt-parent = <0x34>;
	interrupts = <0x3f 0x00>;
	reg = <0x28>;
	qcom,clk-src = "BBCLK2";
	interrupt-names = "nfc_irq";
};

--
Hal: They're going for the kernel!
Margo: Colonel Who?