[PATCH v4 0/3] nfc: st-nci: Fairphone 5 NFC bring-up (ST21NFCD)

[Kristian Brox <isyourbrainfoss@proton.me>]

This adds NFC on the Fairphone 5 (qcm6490). The board uses an ST21NFCD
on I2C. That part speaks raw NCI; the current st-nci driver always
wraps NDLC, so using st,st21nfcb-i2c leaves the adapter unusable.

The series adds a st,st21nfcd compatible for the raw-NCI path and the
Fairphone 5 DT node. Boards that already use st21nfcb / st21nfcc keep
the NDLC path.

Patches are against linux-nfc/for-next (Linux 7.3-rc1). Hardware test
was on a Fairphone 5 running postmarketOS:

- 7.1.2 sc7280, earlier raw-NCI modules: nfctool Powered: Yes;
  initiator poll / neard: NTAG 215, NDEF URI read OK
- 7.2.0-nfc-test+ (sc7280-mainline), this v4 st-nci as modules:
  10x initiator poll finds Type 2 in 0.13-0.14 s, no
  "unsupported ntf opcode 0xf02". Repeat poll with a Type 2 tag
  in the field stays Powered: Yes. Empty-field poll SIGINT
  (nfctool -p, no tag) also stays Powered: Yes.

The ndlc: hexdumps are pr_debug. SIGINT during CORE_RESET (nfctool -0
then Ctrl-C during -1) wedges stock nci core; that is not this series.

ese-present and uicc-present follow the public schematic (NFC_SWP1/SWP2:
SWP_SE to SIM1, SWP_UICC to SIM2). SE/HCE is not tested.

CLK_REQ (GPIO 39) is omitted, as on Fairphone 6 NFC. VBAT and VDD_TX sit
on VPH_PWR and are not modelled. VCC_UICC_IN (L4C) is not modelled;
UICC SWP is untested.

Signed-off-by: Kristian Brox <isyourbrainfoss@proton.me>
---
Link to v3:
https://lore.kernel.org/oe-linux-nfc/20260820-fp5-st21nfcd-v3-v3-0-5ee0a7f44d04@proton.me/

Changes in v4:
- Driver: consume ST proprietary RF NTF 0xf02 (Luca)
- Driver: set raw_nci before nci_register_device (Sashiko / David)
- Driver: enable vdd-io and SYS_CLK before driving reset
- Driver: keep named i2c/acpi id initializers; do not add trailing
  commas on existing of_match entries (David)
- Driver: reset pulse uses gpiod_is_active_low so new DT can be
  GPIO_ACTIVE_LOW without breaking old nfcb DTS (Krzysztof)
- Binding: ST21NFCD is not I2C-only (data brief lists SPI); do not
  put st,st21nfcd in the I2C-only spi-max-frequency:false enum
- Binding: SPI $ref only in the non-I2C else (not a global allOf item)
- Binding: clocks/vdd-io-supply on the existing I2C example; drop the
  extra example (Krzysztof)
- DTS: reset-gpios GPIO_ACTIVE_LOW (Krzysztof). Physical GPIO 38 HIGH
  is the run level. Konrad R-b not carried (polarity changed).

Changes in v3:
- Binding: new compatible is a different ST part (not a driver-sharing note)
- Binding: drop NDLC/raw-NCI description on compatible
- Binding example uses interrupts-extended
- DTS: one nfc_default pinctrl group, pins sorted, no output-high
- Fresh series (not a reply to v1/v2)

Changes in v2:
- Compatible is st,st21nfcd (no -i2c suffix)
- Sent without PGP/MIME
- DTS: interrupts-extended and pinctrl for IRQ/reset
- DTS: ese-present / uicc-present (schematic)
- DTS: SYS_CLK from LN_BB_CLK2, VPS_IO from L18B
- Binding: optional clocks and vdd-io-supply
- Driver: optional clk / vdd-io enable

---
Kristian Brox (3):
      dt-bindings: net: nfc: add st,st21nfcd
      nfc: st-nci: add raw NCI path for ST21NFCD
      arm64: dts: qcom: qcm6490-fairphone-fp5: add ST21NFCD NFC

 .../devicetree/bindings/net/nfc/st,st-nci.yaml     | 49 +++++++++----
 arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts | 34 ++++++++-
 drivers/nfc/st-nci/core.c                          | 22 ++++++
 drivers/nfc/st-nci/i2c.c                           | 82 ++++++++++++++++++++--
 drivers/nfc/st-nci/ndlc.c                          | 27 +++++--
 drivers/nfc/st-nci/ndlc.h                          |  5 +-
 drivers/nfc/st-nci/se.c                            |  3 +
 drivers/nfc/st-nci/spi.c                           |  2 +-
 drivers/nfc/st-nci/st-nci.h                        |  2 +
 9 files changed, 197 insertions(+), 29 deletions(-)
---
base-commit: cee9395acd8043be0644b25c34bfa86623f2b935
change-id: 20260902-fp5-st21nfcd-v4-1685be1d7c52

Best regards,
--  
Kristian Brox <isyourbrainfoss@proton.me>