[PATCH v3 5/5] arm64: dts: qcom: milos-fairphone-fp6: Add NFC

[Jorijn van der Graaf]

Add the Samsung S3NRN4V NCI NFC controller on i2c1. Its XI clock is
provided by the RF_CLK2 PMIC buffer and gated through the controller's
CLK_REQ line on tlmm GPIO6. PVDD is fed from PM7550 LDO20, the rail the
downstream driver switches for this chip.

The enable line is routed to the chip's power-down input, which is
asserted high to turn the chip off (the downstream driver treats VEN as
active-low on this design) -- hence GPIO_ACTIVE_HIGH, unlike the
exynos5433-tm2 wiring of the same driver. The pin is pulled up so the
chip stays off while the line is not driven.

Assisted-by: Claude:claude-opus-4-8
Assisted-by: Claude:claude-fable-5
Signed-off-by: Jorijn van der Graaf <jorijnvdgraaf@xxxxxxxxxxxxx>
---
 .../boot/dts/qcom/milos-fairphone-fp6.dts     | 49 ++++++++++++++++++-
 1 file changed, 47 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/milos-fairphone-fp6.dts b/arch/arm64/boot/dts/qcom/milos-fairphone-fp6.dts
index ebdca0e2d2f3..a1b86e4092fe 100644
--- a/arch/arm64/boot/dts/qcom/milos-fairphone-fp6.dts
+++ b/arch/arm64/boot/dts/qcom/milos-fairphone-fp6.dts
@@ -601,9 +601,29 @@ &gcc {
 };
 
 &i2c1 {
-	/* Samsung NFC @ 0x27 */
-
 	status = "okay";
+
+	/*
+	 * Samsung S3NRN4V NFC controller. XI is driven by the RF_CLK2 PMIC
+	 * buffer; the chip has no oscillator of its own and gates the clock
+	 * via its CLK_REQ line, so the clock must be voted on in response
+	 * to it.
+	 */
+	nfc@27 {
+		compatible = "samsung,s3nrn4v";
+		reg = <0x27>;
+
+		clk-req-gpios = <&tlmm 6 GPIO_ACTIVE_HIGH>;
+		clocks = <&rpmhcc RPMH_RF_CLK2>;
+		en-gpios = <&tlmm 56 GPIO_ACTIVE_HIGH>;
+		interrupt-parent = <&tlmm>;
+		interrupts = <31 IRQ_TYPE_EDGE_RISING>;
+		pinctrl-0 = <&nfc_clk_req_default>, <&nfc_irq_default>,
+			    <&nfc_pd_default>;
+		pinctrl-names = "default";
+		pvdd-supply = <&vreg_l20b>;
+		wake-gpios = <&tlmm 7 GPIO_ACTIVE_HIGH>;
+	};
 };
 
 &i2c3 {
@@ -825,6 +845,31 @@ &tlmm {
 			       <13 1>, /* NC */
 			       <63 2>; /* WLAN UART */
 
+	nfc_clk_req_default: nfc-clk-req-default-state {
+		pins = "gpio6";
+		function = "gpio";
+		drive-strength = <2>;
+		bias-disable;
+	};
+
+	nfc_irq_default: nfc-irq-default-state {
+		pins = "gpio31";
+		function = "gpio";
+		drive-strength = <2>;
+		bias-disable;
+	};
+
+	/*
+	 * Pulled up so the NFC chip stays powered down while the line is
+	 * not driven (it is the chip's active-high power-down input).
+	 */
+	nfc_pd_default: nfc-pd-default-state {
+		pins = "gpio56";
+		function = "gpio";
+		drive-strength = <2>;
+		bias-pull-up;
+	};
+
 	sdc2_card_det_n: sdc2-card-det-state {
 		pins = "gpio65";
 		function = "gpio";
-- 
2.55.0