[PATCH 0/2] PHY: Add MediaTek PCI-Express Gen4 S-PHY Driver

[PATCH 0/2] PHY: Add MediaTek PCI-Express Gen4 S-PHY Driver

[AngeloGioacchino Del Regno]

This adds a driver for the PCI-Express Gen4 "S-PHY" found in the
Genio MT8894, Kompanio MT8196, Dimensity MT6991 SoCs (which are
all variants of the same chip).

This was successfully tested on MT8894 and MT8196.

AngeloGioacchino Del Regno (2):
  dt-bindings: phy: Document MT8196 MediaTek PCI-Express Gen4 S-PHY
  phy: mediatek: Add support for PCI-Express Gen4 S-PHY

 .../phy/mediatek,mt8196-pcie-sphy.yaml        |  91 +++
 drivers/phy/mediatek/Kconfig                  |   9 +
 drivers/phy/mediatek/Makefile                 |   1 +
 drivers/phy/mediatek/phy-mtk-pcie-sphy.c      | 560 ++++++++++++++++++
 4 files changed, 661 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/phy/mediatek,mt8196-pcie-sphy.yaml
 create mode 100644 drivers/phy/mediatek/phy-mtk-pcie-sphy.c

-- 
2.54.0

[PATCH 1/2] dt-bindings: phy: Document MT8196 MediaTek PCI-Express Gen4 S-PHY

[AngeloGioacchino Del Regno]

This adds bindings for the PCI-Express Gen4 S-PHY found in newer
MediaTek SoCs, such as MT8196 and its variants.

In the current "revision 3", depending on the specific port, this
S-PHY supports up to two lanes of PCI-Express Gen 4 and both EP
and RC modes.
It is not clear whether revisions/versions earlier than 3 have
ever been shipped in any other MediaTek SoC.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 .../phy/mediatek,mt8196-pcie-sphy.yaml        | 91 +++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/phy/mediatek,mt8196-pcie-sphy.yaml

diff --git a/Documentation/devicetree/bindings/phy/mediatek,mt8196-pcie-sphy.yaml b/Documentation/devicetree/bindings/phy/mediatek,mt8196-pcie-sphy.yaml
new file mode 100644
index 000000000000..2b61882c402c
--- /dev/null
+++ b/Documentation/devicetree/bindings/phy/mediatek,mt8196-pcie-sphy.yaml
@@ -0,0 +1,91 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/phy/mediatek,mt8196-pcie-sphy.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek PCI-Express Gen4 S-PHY
+
+maintainers:
+  - AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
+
+description:
+  The MediaTek PCI-Express Gen4 S-PHY is capable of data serialization
+  and de-serialization with 8, 10, 128 or 130 bits (16GT/s) encoding
+  and decoding, has analog buffers, elastic buffers and mechanisms for
+  receiver detection.
+  This PHY supports link rates of 2.5, 5.0, 6.0 and 16.0 GT/s per-lane
+  in both Root Complex (RC) and End Point (EP) modes, depending on the
+  chosen port.
+  The Digital PHY (PHYD) part adheres to the Intel PIPE (PHY Interface
+  for the PCIe) specification.
+
+properties:
+  compatible:
+    const: mediatek,mt8196-pcie-sphy
+
+  reg:
+    minItems: 2
+
+  reg-names:
+    items:
+      - const: sif
+      - const: ckm
+
+  "#phy-cells":
+    const: 0
+
+  nvmem-cells:
+    items:
+      - description: Internal resistor selection of TX Bias Current
+      - description: XTP Bias V2V voltage calibration
+      - description: S-PLL CKTX Impedance Selection (P-MOSFET side)
+      - description: S-PLL CKTX Impedance Selection (N-MOSFET side)
+      - description: S-PLL CKTX Intermediate Transition Impedance
+      - description: RX Front-End Return Loss Continuous Time Linear EQ
+      - description: RX Front-End Return Loss Variable Gain Amplifier
+      - description: RX Front-End Return Loss Decision Feedback EQ
+      - description: RX Impedance Selection
+      - description: TX Impedance Selection (P-MOSFET side)
+      - description: TX Impedance Selection (N-MOSFET side)
+      - description: TX Lane 0 Switch Resistance (RSWn)
+      - description: TX Lane 1 Switch Resistance (RSWn)
+      - description: eFuse calibration table version
+
+  nvmem-cell-names:
+    items:
+      - const: int-r
+      - const: xtp-vtrim
+      - const: cktx-pmos
+      - const: cktx-nmos
+      - const: cktx-r-mid
+      - const: rxfe-lanes-rl-ctle
+      - const: rxfe-lanes-rl-vga
+      - const: rxfe-lanes-rl-dfe
+      - const: rx-lanes-imp
+      - const: tx-lanes-pmos
+      - const: tx-lanes-nmos
+      - const: tx-ln0-rswn
+      - const: tx-ln1-rswn
+      - const: cal-version
+
+  power-domains:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - "#phy-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    phy@16900000 {
+        compatible = "mediatek,mt8196-pcie-sphy";
+        reg = <0x16900000 0x10000>, <0x16920000 0x10000>;
+        reg-names = "sif", "ckm";
+        power-domains = <&spm 10>;
+        #phy-cells = <0>;
+    };
-- 
2.54.0

Re: [PATCH 1/2] dt-bindings: phy: Document MT8196 MediaTek PCI-Express Gen4 S-PHY

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Missing upper bound (`maxItems`) for the `reg` property array.
--

--- Patch [1]: [PATCH 1/2] dt-bindings: phy: Document MT8196 MediaTek PCI-Express Gen4 S-PHY ---
commit 46cb0bc5744a1aaeece570f9d383cc948bbcab79
Author: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

dt-bindings: phy: Document MT8196 MediaTek PCI-Express Gen4 S-PHY

This commit introduces the device tree binding documentation for the
PCI-Express Gen4 S-PHY found in newer MediaTek SoCs like the MT8196. It
details the required properties, nvmem cells, and power domains for this
hardware.

> diff --git a/Documentation/devicetree/bindings/phy/mediatek,mt8196-pcie-sphy.yaml b/Documentation/devicetree/bindings/phy/mediatek,mt8196-pcie-sphy.yaml
> new file mode 100644
> index 0000000000000..2b61882c402c2
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/phy/mediatek,mt8196-pcie-sphy.yaml
[ ... ]
> +properties:
> +  compatible:
> +    const: mediatek,mt8196-pcie-sphy
> +
> +  reg:
> +    minItems: 2
> +
> +  reg-names:
> +    items:
> +      - const: sif
> +      - const: ckm

[Severity: Low]
Is an upper bound missing for the reg property array here?

The schema defines minItems: 2 but omits maxItems. Since reg-names explicitly
defines exactly two items, should reg include maxItems: 2 as well to fully
bound the array and prevent potential dt_binding_check validation warnings?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260716151333.77254-1-angelogioacchino.delregno@collabora.com?part=1

[PATCH 2/2] phy: mediatek: Add support for PCI-Express Gen4 S-PHY

[AngeloGioacchino Del Regno]

Add support for the PCI-Express Gen4 S-PHY found in the latest
MediaTek SoCs, including MT8196, MT8894 and similar.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 drivers/phy/mediatek/Kconfig             |   9 +
 drivers/phy/mediatek/Makefile            |   1 +
 drivers/phy/mediatek/phy-mtk-pcie-sphy.c | 560 +++++++++++++++++++++++
 3 files changed, 570 insertions(+)
 create mode 100644 drivers/phy/mediatek/phy-mtk-pcie-sphy.c

diff --git a/drivers/phy/mediatek/Kconfig b/drivers/phy/mediatek/Kconfig
index ba6461350951..77236f3084c8 100644
--- a/drivers/phy/mediatek/Kconfig
+++ b/drivers/phy/mediatek/Kconfig
@@ -13,6 +13,15 @@ config PHY_MTK_PCIE
 	  callback for PCIe GEN3 port, it supports software efuse
 	  initialization.
 
+config PHY_MTK_PCIE_SPHY
+	tristate "MediaTek PCIe S-PHY Driver"
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+	depends on OF
+	select GENERIC_PHY
+	help
+	  Say 'Y' here to add support for MediaTek PCIe S-PHY driver for
+	  PCI-Express Gen4 controllers as found in MT6991, MT8196 and others.
+
 config PHY_MTK_XFI_TPHY
 	tristate "MediaTek 10GE SerDes XFI T-PHY driver"
 	depends on ARCH_MEDIATEK || COMPILE_TEST
diff --git a/drivers/phy/mediatek/Makefile b/drivers/phy/mediatek/Makefile
index ed0da708759b..7e984c7cfea3 100644
--- a/drivers/phy/mediatek/Makefile
+++ b/drivers/phy/mediatek/Makefile
@@ -5,6 +5,7 @@
 
 obj-$(CONFIG_PHY_MTK_DP)		+= phy-mtk-dp.o
 obj-$(CONFIG_PHY_MTK_PCIE)		+= phy-mtk-pcie.o
+obj-$(CONFIG_PHY_MTK_PCIE_SPHY)		+= phy-mtk-pcie-sphy.o
 obj-$(CONFIG_PHY_MTK_TPHY)		+= phy-mtk-tphy.o
 obj-$(CONFIG_PHY_MTK_UFS)		+= phy-mtk-ufs.o
 obj-$(CONFIG_PHY_MTK_XSPHY)		+= phy-mtk-xsphy.o
diff --git a/drivers/phy/mediatek/phy-mtk-pcie-sphy.c b/drivers/phy/mediatek/phy-mtk-pcie-sphy.c
new file mode 100644
index 000000000000..c794505060a8
--- /dev/null
+++ b/drivers/phy/mediatek/phy-mtk-pcie-sphy.c
@@ -0,0 +1,560 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022 MediaTek Inc.
+ * Copyright (c) 2026 Collabora Ltd.
+ *                    AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/module.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include "phy-mtk-io.h"
+
+/* PHY System Interface (SIF) registers */
+#define PEXTP_DIG_GLB_TOP				0x20
+#  define RG_XTP_BYPASS_PIPE_RST_RC			BIT(17)
+#define PEXTP_DIG_GLB_CKBG0				0x30
+#  define RG_XTP_CKBG_XTAL_STABLE_TIME_SEL		GENMASK(25, 16)
+#define PEXTP_DIG_GLB_TPLL_CTL0				0x38
+#  define RG_XTP_TPLL_SET_STABLE_TIME_SEL		GENMASK(7, 2)
+#  define RG_XTP_TPLL_PWE_ON_STABLE_TIME_SEL		GENMASK(9, 8)
+#define PEXTP_DIG_GLB_CLKREQ_CTL			0x50
+#  define RG_XTP_CKM_EN_L1S0				BIT(13)
+#  define RG_XTP_CKM_EN_L1S1				BIT(14)
+#define PEXTP_DIG_GLB_TPLL_CTL2				0xf4
+#  define RG_XTP_TPLL_ISO_EN_STABLE_TIME_SEL		GENMASK(13, 12)
+
+/* PHY System Interface Digital registers */
+#define PEXTP_DIG_LN_TRX_PIPE_IF_17			0x30e8
+#  define RG_XTP_LN_RX_LF_CTLE_CSEL_GEN4		GENMASK(14, 12)
+#define PEXTP_DIG_LN_RX_F0				0x50f0
+#  define RG_XTP_LN_RX_GEN1_CTLE1_CSEL			GENMASK(3, 0)
+#  define RG_XTP_LN_RX_GEN2_CTLE1_CSEL			GENMASK(7, 4)
+#  define RG_XTP_LN_RX_GEN3_CTLE1_CSEL			GENMASK(11, 8)
+#  define RG_XTP_LN_RX_GEN4_CTLE1_CSEL			GENMASK(15, 12)
+#define PEXTP_DIG_LN_RX2_AEQ_EDGE_0			0x6004
+#  define RG_XTP_LN_RX_AEQ_EGEQ_RATIO_GEN3		GENMASK(21, 16)
+#  define RG_XTP_LN_RX_AEQ_EGEQ_RATIO_GEN4		GENMASK(29, 24)
+#  define AEQ_EGEQ_RATIO_GEN3_TO_22			0x16
+#  define AEQ_EGEQ_RATIO_GEN4_TO_22			0x16
+
+/* PHY System Interface Analog registers */
+#define PEXTP_ANA_GLB_TPLL1_RSVD			0x902c
+#  define RG_XTP_GLB_TPLL1_P_PATH_GAIN			GENMASK(2, 0)
+#define PEXTP_ANA_GLB_BIAS_0				0x9060
+#  define RG_XTP_GLB_BIAS_INTR_CTRL			GENMASK(5, 0)
+#define PEXTP_ANA_GLB_BIAS_1				0x90c0
+#  define RG_XTP_GLB_BIAS_V2V_VTRIM			GENMASK(9, 6)
+#define PEXTP_ANA_LN_TRX_0C				0xa00c
+#  define RG_XTP_LN_TX_RSWN_IMPSEL			GENMASK(20, 16)
+#define PEXTP_ANA_LN_TRX_34				0xa034
+#  define RG_XTP_LN_RX_FE				BIT(15)
+#define PEXTP_ANA_LN_TRX_6C				0xa06c
+#  define RG_XTP_LN_RX_AEQ_CTLE_ERR_TYPE		GENMASK(14, 13)
+#   define AEQ_CTLE_SEARCH_ERR_TYPE_H1P5		0
+#   define AEQ_CTLE_SEARCH_ERR_TYPE_H1P5_H2P5		1
+#   define AEQ_CTLE_SEARCH_ERR_TYPE_P1P5_H2P5_H3P5	2
+#define PEXTP_ANA_LN_TRX_A0				0xa0a0
+#  define RG_XTP_LN_TX_IMPSEL_PMOS			GENMASK(4, 0)
+#  define RG_XTP_LN_TX_IMPSEL_NMOS			GENMASK(11, 7)
+#  define RG_XTP_LN_RX_IMPSEL				GENMASK(15, 12)
+#define PEXTP_ANA_LN_TRX_A8				0xa0a8
+#  define RG_XTP_LN_RX_LEQ_RL_CTLE_CAL			GENMASK(6, 2)
+#  define RG_XTP_LN_RX_LEQ_RL_VGA_CAL			GENMASK(11, 7)
+#  define RG_XTP_LN_RX_LEQ_RL_DFE_CAL			GENMASK(23, 19)
+#define PEXTP_DIG_LN_TX_LC_TABLE_RSWN_4			0xb004
+#define PEXTP_DIG_LN_TX_LC_TABLE_RSWN_8			0xb008
+#define PEXTP_DIG_LN_TX_LC_TABLE_RSWN_C			0xb00c
+#define PEXTP_DIG_LN_TX_LC_TABLE_RSWN_10		0xb010
+#define PEXTP_DIG_LN_TX_LC_TABLE_RSWN_14		0xb014
+#define PEXTP_DIG_LN_TX_LC_TABLE_RSWN_18		0xb018
+#  define RG_XTP_LN_TX_LC_PRESET_MGx_Px_CM1		GENMASK(5, 0)
+#  define RG_XTP_LN_TX_LC_PRESET_MGx_Px_C0		GENMASK(13, 8)
+#  define RG_XTP_LN_TX_LC_PRESET_MGx_Px_CP1		GENMASK(21, 16)
+#define PEXTP_REG_LANE(x)				((x) * 0x100)
+
+/* PHY Clock Management (CKM) registers */
+#define XTP_CKM_FORCE_6					0x38
+#  define RG_CKM_BIAS_WAIT_PRD_US			GENMASK(21, 16)
+#define XTP_CKM_REG_SPLL_FBKDIV_5			0xd4
+#  define RG_CKM_CKTX_IMPSEL_PMOS			GENMASK(19, 16)
+#  define RG_CKM_CKTX_IMPSEL_NMOS			GENMASK(23, 20)
+#  define RG_CKM_CKTX_IMPSEL_SW				GENMASK(27, 24)
+
+/* Calibration data from eFuses */
+#define MTK_PCIE_SPHY_CALIBRATION_MAX_DATA_LANES	2
+#define MTK_PCIE_SPHY_CALIBRATION_LAST_QUIRK_VER	4
+
+/**
+ * struct mtk_pcie_sphy_imp_sel - Impedance Selection parameters
+ * @pmos: Impedance selection for P-Channel MOSFET
+ * @nmos: Impedance selection for N-Channel MOSFET
+ */
+struct mtk_pcie_sphy_imp_sel {
+	u8 pmos : 4;
+	u8 nmos : 4;
+};
+
+/**
+ * struct mtk_pcie_sphy_efuse - eFuse calibration data for S-PHY
+ * @int_r_ctrl:     Internal resistor selection of TX Bias Current
+ * @xtp_vtrim:      XTP Bias V2V voltage calibration
+ * @cktx_impsel:    SPLL CKTX Impedance Selection (P and N MOSFET)
+ * @cktx_r_mid:     SPLL CKTX Intermediate Transition Impedance (Rmid)
+ * @rx_leq_rl_ctle: RX Front-End Return Loss Continuous Time Linear Equalization value
+ * @rx_leq_rl_vga:  RX Front-End Return Loss Variable Gain Amplifier value
+ * @rx_leq_rl_dfe:  RX Front-End Return Loss Decision Feedback Equalization value
+ * @rx_impsel:      RX Impedance Selection
+ * @tx_impsel:      TX Impedance Selection (P and N MOSFET)
+ * @tx_rswn_impsel: TX RSWn (Switch Resistance) impedance selection
+ * @supported:      eFuse calibration data is supported
+ */
+struct mtk_pcie_sphy_efuse {
+	u8 int_r_ctrl;
+	u8 xtp_vtrim;
+	struct mtk_pcie_sphy_imp_sel cktx_impsel;
+	u8 cktx_r_mid;
+	u8 rx_leq_rl_ctle;
+	u8 rx_leq_rl_vga;
+	u8 rx_leq_rl_dfe;
+	u8 rx_impsel;
+	struct mtk_pcie_sphy_imp_sel tx_impsel;
+	u8 tx_rswn_impsel[MTK_PCIE_SPHY_CALIBRATION_MAX_DATA_LANES];
+	bool supported;
+};
+
+/**
+ * struct mtk_pcie_sphy - PCI-Express S-PHY driver main structure
+ * @dev:         Pointer to device structure
+ * @phy:         Pointer to generic phy structure
+ * @sif_base:    IO mapped register base address of system interface
+ * @ckm_base:    IO mapped register base address of clock management interface
+ * @num_lanes:   Number of lanes
+ * @calibration: eFuse calibration data for S-PHY
+ */
+struct mtk_pcie_sphy {
+	struct device *dev;
+	struct phy *phy;
+	void __iomem *sif_base;
+	void __iomem *ckm_base;
+	u8 num_lanes;
+	struct mtk_pcie_sphy_efuse calibration;
+};
+
+static void mtk_pcie_sphy_apply_calibration(struct mtk_pcie_sphy *pcie_sphy)
+{
+	struct mtk_pcie_sphy_efuse *cal = &pcie_sphy->calibration;
+	int i;
+
+	mtk_phy_update_field(pcie_sphy->sif_base + PEXTP_ANA_GLB_BIAS_0,
+			     RG_XTP_GLB_BIAS_INTR_CTRL, cal->int_r_ctrl);
+
+	mtk_phy_update_field(pcie_sphy->sif_base + PEXTP_ANA_GLB_BIAS_1,
+			     RG_XTP_GLB_BIAS_V2V_VTRIM, cal->xtp_vtrim);
+
+	mtk_phy_update_field(pcie_sphy->ckm_base + XTP_CKM_REG_SPLL_FBKDIV_5,
+			     RG_CKM_CKTX_IMPSEL_PMOS, cal->cktx_impsel.pmos);
+
+	mtk_phy_update_field(pcie_sphy->ckm_base + XTP_CKM_REG_SPLL_FBKDIV_5,
+			     RG_CKM_CKTX_IMPSEL_NMOS, cal->cktx_impsel.nmos);
+
+	mtk_phy_update_field(pcie_sphy->ckm_base + XTP_CKM_REG_SPLL_FBKDIV_5,
+			     RG_CKM_CKTX_IMPSEL_SW, cal->cktx_r_mid);
+
+	for (i = 0; i < pcie_sphy->num_lanes; i++) {
+		void __iomem *sif_lane_base = pcie_sphy->sif_base + PEXTP_REG_LANE(i);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_ANA_LN_TRX_0C,
+				     RG_XTP_LN_TX_RSWN_IMPSEL, cal->tx_rswn_impsel[i]);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_ANA_LN_TRX_A8,
+				     RG_XTP_LN_RX_LEQ_RL_CTLE_CAL, cal->rx_leq_rl_ctle);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_ANA_LN_TRX_A8,
+				     RG_XTP_LN_RX_LEQ_RL_VGA_CAL, cal->rx_leq_rl_vga);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_ANA_LN_TRX_A8,
+				     RG_XTP_LN_RX_LEQ_RL_DFE_CAL, cal->rx_leq_rl_dfe);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_ANA_LN_TRX_A0,
+				     RG_XTP_LN_RX_IMPSEL, cal->rx_impsel);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_ANA_LN_TRX_A0,
+				     RG_XTP_LN_TX_IMPSEL_PMOS, cal->tx_impsel.pmos);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_ANA_LN_TRX_A0,
+				     RG_XTP_LN_TX_IMPSEL_NMOS, cal->tx_impsel.nmos);
+	}
+}
+
+/**
+ * mtk_pcie_sphy_init() - Initialize the PCI-Express S-PHY
+ * @phy: the phy to be initialized
+ *
+ * The hardware settings will be reset during suspend, it should be
+ * reinitialized when the consumer calls phy_init() again on resume.
+ */
+static int mtk_pcie_sphy_init(struct phy *phy)
+{
+	struct mtk_pcie_sphy *pcie_sphy = phy_get_drvdata(phy);
+	struct mtk_pcie_sphy_imp_sel tx_impsel;
+	int i;
+
+	/* Set CKM Bias wait time to 4 microseconds */
+	mtk_phy_update_field(pcie_sphy->ckm_base + XTP_CKM_FORCE_6,
+			     RG_CKM_BIAS_WAIT_PRD_US, 4);
+
+	/* TPLL needs 63 ref_ck ticks to stabilize when setting frequency */
+	mtk_phy_update_field(pcie_sphy->sif_base + PEXTP_DIG_GLB_TPLL_CTL0,
+			     RG_XTP_TPLL_SET_STABLE_TIME_SEL, 63);
+
+	/* TPLL needs 3 ref_ck ticks to stabilize when powering on... */
+	mtk_phy_update_field(pcie_sphy->sif_base + PEXTP_DIG_GLB_TPLL_CTL0,
+			     RG_XTP_TPLL_PWE_ON_STABLE_TIME_SEL, 3);
+
+	/* ...and the same goes for setting isolation */
+	mtk_phy_update_field(pcie_sphy->sif_base + PEXTP_DIG_GLB_TPLL_CTL2,
+			     RG_XTP_TPLL_ISO_EN_STABLE_TIME_SEL, 3);
+
+	/* XTAL doesn't need any stabilization time */
+	mtk_phy_update_field(pcie_sphy->sif_base + PEXTP_DIG_GLB_CKBG0,
+			     RG_XTP_CKBG_XTAL_STABLE_TIME_SEL, 0);
+
+	/* Keep pextp_ckm enabled when in L1SS_L1S1 state */
+	mtk_phy_clear_bits(pcie_sphy->sif_base + PEXTP_DIG_GLB_CLKREQ_CTL, RG_XTP_CKM_EN_L1S1);
+
+	/* Set PIPE to reset TPLL */
+	mtk_phy_clear_bits(pcie_sphy->sif_base + PEXTP_DIG_GLB_TOP, RG_XTP_BYPASS_PIPE_RST_RC);
+
+	/* Set TPLL P-Path gain compensation to 1 */
+	mtk_phy_update_field(pcie_sphy->sif_base + PEXTP_ANA_GLB_TPLL1_RSVD,
+			     RG_XTP_GLB_TPLL1_P_PATH_GAIN, 1);
+
+	for (i = 0; i < pcie_sphy->num_lanes; i++) {
+		void __iomem *sif_lane_base = pcie_sphy->sif_base + PEXTP_REG_LANE(i);
+
+		/* Set RX Lane AEQ CTRL-E Search Error type to h1.5 + h2.5 */
+		mtk_phy_update_field(sif_lane_base + PEXTP_ANA_LN_TRX_6C,
+				     RG_XTP_LN_RX_AEQ_CTLE_ERR_TYPE,
+				     AEQ_CTLE_SEARCH_ERR_TYPE_H1P5_H2P5);
+
+		mtk_phy_set_bits(sif_lane_base + PEXTP_ANA_LN_TRX_34, RG_XTP_LN_RX_FE);
+
+		/* TRX: Select CTLE1 for RX Lane AutoEQ CTRL-E Setting on Gen4 */
+		mtk_phy_update_field(sif_lane_base + PEXTP_DIG_LN_TRX_PIPE_IF_17,
+				     RG_XTP_LN_RX_LF_CTLE_CSEL_GEN4, 1);
+
+		/* Set RX Lane AutoEQ CTRL-E for PCI-Express Gen1 to Gen 4 */
+		mtk_phy_update_field(sif_lane_base + PEXTP_DIG_LN_RX_F0,
+				     RG_XTP_LN_RX_GEN1_CTLE1_CSEL, 13);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_DIG_LN_RX_F0,
+				     RG_XTP_LN_RX_GEN2_CTLE1_CSEL, 13);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_DIG_LN_RX_F0,
+				     RG_XTP_LN_RX_GEN3_CTLE1_CSEL, 13);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_DIG_LN_RX_F0,
+				     RG_XTP_LN_RX_GEN4_CTLE1_CSEL, 0);
+
+		/* Set RX Lane AutoEQ's Edge EQ Ratio to 22 * 0.0625 = 1.375 */
+		mtk_phy_update_field(sif_lane_base + PEXTP_DIG_LN_RX2_AEQ_EDGE_0,
+				     RG_XTP_LN_RX_AEQ_EGEQ_RATIO_GEN3, 22);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_DIG_LN_RX2_AEQ_EDGE_0,
+				     RG_XTP_LN_RX_AEQ_EGEQ_RATIO_GEN4, 22);
+
+		/* Setup Digital lane TX Link Characteristics Table */
+		mtk_phy_update_field(sif_lane_base + PEXTP_DIG_LN_TX_LC_TABLE_RSWN_4,
+				     RG_XTP_LN_TX_LC_PRESET_MGx_Px_C0, 10);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_DIG_LN_TX_LC_TABLE_RSWN_4,
+				     RG_XTP_LN_TX_LC_PRESET_MGx_Px_CP1, 2);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_DIG_LN_TX_LC_TABLE_RSWN_8,
+				     RG_XTP_LN_TX_LC_PRESET_MGx_Px_C0, 11);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_DIG_LN_TX_LC_TABLE_RSWN_8,
+				     RG_XTP_LN_TX_LC_PRESET_MGx_Px_CP1, 1);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_DIG_LN_TX_LC_TABLE_RSWN_C,
+				     RG_XTP_LN_TX_LC_PRESET_MGx_Px_C0, 12);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_DIG_LN_TX_LC_TABLE_RSWN_10,
+				     RG_XTP_LN_TX_LC_PRESET_MGx_Px_C0, 13);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_DIG_LN_TX_LC_TABLE_RSWN_10,
+				     RG_XTP_LN_TX_LC_PRESET_MGx_Px_CM1, 1);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_DIG_LN_TX_LC_TABLE_RSWN_14,
+				     RG_XTP_LN_TX_LC_PRESET_MGx_Px_C0, 11);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_DIG_LN_TX_LC_TABLE_RSWN_14,
+				     RG_XTP_LN_TX_LC_PRESET_MGx_Px_CM1, 1);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_DIG_LN_TX_LC_TABLE_RSWN_18,
+				     RG_XTP_LN_TX_LC_PRESET_MGx_Px_C0, 10);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_DIG_LN_TX_LC_TABLE_RSWN_18,
+				     RG_XTP_LN_TX_LC_PRESET_MGx_Px_CM1, 2);
+	}
+
+	if (pcie_sphy->calibration.supported) {
+		mtk_pcie_sphy_apply_calibration(pcie_sphy);
+
+		tx_impsel.pmos = pcie_sphy->calibration.tx_impsel.pmos;
+		tx_impsel.nmos = pcie_sphy->calibration.tx_impsel.nmos;
+	} else {
+		/* Set P=10, N=9 to prevent EMI if no calibration present */
+		tx_impsel.pmos = 10;
+		tx_impsel.nmos = 9;
+	}
+
+	/* Select TX Impedance on N and P MOSFETs */
+	for (i = 0; i < pcie_sphy->num_lanes; i++) {
+		void __iomem *sif_lane_base = pcie_sphy->sif_base + PEXTP_REG_LANE(i);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_ANA_LN_TRX_A0,
+				     RG_XTP_LN_TX_IMPSEL_PMOS, tx_impsel.pmos);
+
+		mtk_phy_update_field(sif_lane_base + PEXTP_ANA_LN_TRX_A0,
+				     RG_XTP_LN_TX_IMPSEL_NMOS, tx_impsel.nmos);
+	}
+
+	return 0;
+}
+
+static const struct phy_ops mtk_pcie_sphy_ops = {
+	.init	= mtk_pcie_sphy_init,
+	.owner	= THIS_MODULE,
+};
+
+static int mtk_pcie_sphy_get_one_cal_para(struct device *dev, const char *name, u8 max_val)
+{
+	u16 buf;
+	u8 tmp;
+	int ret;
+
+	/*
+	 * All of the calibrations are always max 8 bits long, but some may
+	 * be split between two different 8-bits cells: handle this corner
+	 * case by retrying reading as u16.
+	 */
+	ret = nvmem_cell_read_u8(dev, name, &tmp);
+	if (ret == 0)
+		buf = tmp;
+	else
+		ret = nvmem_cell_read_u16(dev, name, &buf);
+
+	if (ret) {
+		dev_err(dev, "Cannot get calibration data for %s: %d\n", name, ret);
+		return ret;
+	};
+
+	if (buf == 0) {
+		dev_warn(dev, "No calibration for %s. Using defaults\n", name);
+		return -ENOENT;
+	}
+
+	if (buf > max_val) {
+		dev_err(dev, "Bad value %u retrieved for %s. Returning.\n", buf, name);
+		return -ERANGE;
+	};
+
+	return buf;
+}
+
+static int mtk_pcie_sphy_get_calibration_data(struct mtk_pcie_sphy *pcie_sphy)
+{
+	struct mtk_pcie_sphy_efuse *cal = &pcie_sphy->calibration;
+	struct device *dev = pcie_sphy->dev;
+	u8 version;
+	int ret;
+
+	ret = mtk_pcie_sphy_get_one_cal_para(dev, "int-r",
+					     FIELD_MAX(RG_XTP_GLB_BIAS_INTR_CTRL));
+	if (ret < 0)
+		goto end;
+	cal->int_r_ctrl = ret;
+
+	ret = mtk_pcie_sphy_get_one_cal_para(dev, "xtp-vtrim",
+					     FIELD_MAX(RG_XTP_GLB_BIAS_V2V_VTRIM));
+	if (ret < 0)
+		goto end;
+	cal->xtp_vtrim = ret;
+
+	ret = mtk_pcie_sphy_get_one_cal_para(dev, "cktx-pmos",
+					     FIELD_MAX(RG_CKM_CKTX_IMPSEL_PMOS));
+	if (ret < 0)
+		goto end;
+	cal->cktx_impsel.pmos = ret;
+
+	ret = mtk_pcie_sphy_get_one_cal_para(dev, "cktx-nmos",
+					     FIELD_MAX(RG_CKM_CKTX_IMPSEL_NMOS));
+	if (ret < 0)
+		goto end;
+	cal->cktx_impsel.nmos = ret;
+
+	ret = mtk_pcie_sphy_get_one_cal_para(dev, "cktx-r-mid",
+					     FIELD_MAX(RG_CKM_CKTX_IMPSEL_SW));
+	if (ret < 0)
+		goto end;
+	cal->cktx_r_mid = ret;
+
+	ret = mtk_pcie_sphy_get_one_cal_para(dev, "rxfe-lanes-rl-ctle",
+					     FIELD_MAX(RG_XTP_LN_RX_LEQ_RL_CTLE_CAL));
+	if (ret < 0)
+		goto end;
+	cal->rx_leq_rl_ctle = ret;
+
+	ret = mtk_pcie_sphy_get_one_cal_para(dev, "rxfe-lanes-rl-vga",
+					     FIELD_MAX(RG_XTP_LN_RX_LEQ_RL_VGA_CAL));
+	if (ret < 0)
+		goto end;
+	cal->rx_leq_rl_vga = ret;
+
+	ret = mtk_pcie_sphy_get_one_cal_para(dev, "rxfe-lanes-rl-dfe",
+					     FIELD_MAX(RG_XTP_LN_RX_LEQ_RL_DFE_CAL));
+	if (ret < 0)
+		goto end;
+	cal->rx_leq_rl_dfe = ret;
+
+	ret = mtk_pcie_sphy_get_one_cal_para(dev, "rx-lanes-imp",
+					     FIELD_MAX(RG_XTP_LN_RX_IMPSEL));
+	if (ret < 0)
+		goto end;
+	cal->rx_impsel = ret;
+
+	ret = mtk_pcie_sphy_get_one_cal_para(dev, "tx-lanes-pmos",
+					     FIELD_MAX(RG_XTP_LN_TX_IMPSEL_PMOS));
+	if (ret < 0)
+		goto end;
+	cal->tx_impsel.pmos = ret;
+
+	ret = mtk_pcie_sphy_get_one_cal_para(dev, "tx-lanes-nmos",
+					     FIELD_MAX(RG_XTP_LN_TX_IMPSEL_NMOS));
+	if (ret < 0)
+		goto end;
+	cal->tx_impsel.nmos = ret;
+
+	ret = mtk_pcie_sphy_get_one_cal_para(dev, "tx-ln0-rswn",
+					     FIELD_MAX(RG_XTP_LN_TX_RSWN_IMPSEL));
+	if (ret < 0)
+		goto end;
+	cal->tx_rswn_impsel[0] = ret;
+
+	ret = mtk_pcie_sphy_get_one_cal_para(dev, "tx-ln1-rswn",
+					     FIELD_MAX(RG_XTP_LN_TX_RSWN_IMPSEL));
+	if (ret < 0)
+		goto end;
+	cal->tx_rswn_impsel[1] = ret;
+
+	ret = mtk_pcie_sphy_get_one_cal_para(dev, "cal-version", 15);
+	if (ret < 0)
+		goto end;
+	version = ret;
+
+	/* Quirk for eFuse calibration table versions 0 to 4 */
+	if ((version <= MTK_PCIE_SPHY_CALIBRATION_LAST_QUIRK_VER) &&
+	    cal->rx_leq_rl_ctle == 10) {
+		cal->rx_leq_rl_vga = cal->rx_leq_rl_ctle;
+		cal->rx_leq_rl_dfe = cal->rx_leq_rl_ctle;
+	}
+
+end:
+	if (ret < 0) {
+		/*
+		 * If any of the calibration values is missing, or if there is
+		 * no calibration at all in the eFuses, this is not a problem,
+		 * as the PHY doesn't require one to actually work.
+		 */
+		if (ret == -ENOENT) {
+			cal->supported = false;
+			return 0;
+		}
+		return ret;
+	};
+	cal->supported = true;
+
+	return 0;
+}
+
+static int mtk_pcie_sphy_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct phy_provider *provider;
+	struct mtk_pcie_sphy *pcie_sphy;
+	u32 num_lanes;
+	int ret;
+
+	pcie_sphy = devm_kzalloc(dev, sizeof(*pcie_sphy), GFP_KERNEL);
+	if (!pcie_sphy)
+		return -ENOMEM;
+
+	pcie_sphy->sif_base = devm_platform_ioremap_resource_byname(pdev, "sif");
+	if (IS_ERR(pcie_sphy->sif_base))
+		return dev_err_probe(dev, PTR_ERR(pcie_sphy->sif_base),
+				     "Failed to map phy-sif base\n");
+
+	pcie_sphy->ckm_base = devm_platform_ioremap_resource_byname(pdev, "ckm");
+	if (IS_ERR(pcie_sphy->ckm_base))
+		return dev_err_probe(dev, PTR_ERR(pcie_sphy->ckm_base),
+				     "Failed to map phy-ckm base\n");
+
+	pcie_sphy->phy = devm_phy_create(dev, dev->of_node, &mtk_pcie_sphy_ops);
+	if (IS_ERR(pcie_sphy->phy))
+		return dev_err_probe(dev, PTR_ERR(pcie_sphy->phy),
+				     "Failed to create PCIe phy\n");
+
+	ret = of_property_read_u32(dev->of_node, "num-lanes", &num_lanes);
+	if (ret)
+		num_lanes = 1;
+	else if (num_lanes > 4)
+		return dev_err_probe(dev, -EINVAL, "Invalid number of lanes.\n");
+
+	pcie_sphy->num_lanes = num_lanes;
+	pcie_sphy->dev = dev;
+
+	if (pcie_sphy->num_lanes <= MTK_PCIE_SPHY_CALIBRATION_MAX_DATA_LANES) {
+		ret = mtk_pcie_sphy_get_calibration_data(pcie_sphy);
+		if (ret)
+			return ret;
+	}
+
+	phy_set_drvdata(pcie_sphy->phy, pcie_sphy);
+
+	provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+	if (IS_ERR(provider))
+		return dev_err_probe(dev, PTR_ERR(provider),
+				     "Could not register PCI-Express S-PHY\n");
+
+	ret = devm_pm_runtime_enable(dev);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static const struct of_device_id mtk_pcie_sphy_of_match[] = {
+	{ .compatible = "mediatek,mt8196-pcie-sphy" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mtk_pcie_sphy_of_match);
+
+static struct platform_driver mtk_pcie_sphy_driver = {
+	.probe	= mtk_pcie_sphy_probe,
+	.driver	= {
+		.name = "mtk-pcie-sphy",
+		.of_match_table = mtk_pcie_sphy_of_match,
+	},
+};
+module_platform_driver(mtk_pcie_sphy_driver);
+
+MODULE_DESCRIPTION("MediaTek PCIe SPHY driver");
+MODULE_AUTHOR("AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>");
+MODULE_LICENSE("GPL");
-- 
2.54.0

Re: [PATCH 2/2] phy: mediatek: Add support for PCI-Express Gen4 S-PHY

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 7 potential issue(s) to consider:
- [High] The 4-bit bitfields in `struct mtk_pcie_sphy_imp_sel` will silently truncate 5-bit TX impedance calibration values.
- [High] Probe fails when CONFIG_NVMEM is disabled due to unhandled -EOPNOTSUPP.
- [Medium] Unconditional read of lane 1 calibration data needlessly disables calibration entirely for 1-lane PHYs.
- [Medium] Valid calibration data containing the value '0' incorrectly aborts the entire calibration process.
- [Medium] PHY provider is registered before Runtime PM is enabled, creating a probe race condition.
- [Low] Expected missing calibration data and probe deferrals trigger unconditional dev_err() logs.
- [Low] Missing `#include <linux/pm_runtime.h>` while using `devm_pm_runtime_enable()`.
--

--- Patch [2]: [PATCH 2/2] phy: mediatek: Add support for PCI-Express Gen4 S-PHY ---
commit 7cbdba90e32bbdc889bb04306231fd5de6141303
Author: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

phy: mediatek: Add support for PCI-Express Gen4 S-PHY

Add support for the PCI-Express Gen4 S-PHY found in the latest
MediaTek SoCs, including MT8196, MT8894 and similar.

> diff --git a/drivers/phy/mediatek/phy-mtk-pcie-sphy.c b/drivers/phy/mediatek/phy-mtk-pcie-sphy.c
> new file mode 100644
> --- /dev/null
> +++ b/drivers/phy/mediatek/phy-mtk-pcie-sphy.c
> @@ -0,0 +1,560 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2022 MediaTek Inc.
> + * Copyright (c) 2026 Collabora Ltd.
> + *                    AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/module.h>
> +#include <linux/nvmem-consumer.h>
> +#include <linux/of.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>

[Severity: Low]
Does this need linux/pm_runtime.h included since devm_pm_runtime_enable()
is used later in the file?

[ ... ]

> +/**
> + * struct mtk_pcie_sphy_imp_sel - Impedance Selection parameters
> + * @pmos: Impedance selection for P-Channel MOSFET
> + * @nmos: Impedance selection for N-Channel MOSFET
> + */
> +struct mtk_pcie_sphy_imp_sel {
> +	u8 pmos : 4;
> +	u8 nmos : 4;
> +};

[Severity: High]
Can this truncate calibration values? The eFuse data read for tx-lanes-pmos
and tx-lanes-nmos uses FIELD_MAX(RG_XTP_LN_TX_IMPSEL_PMOS), which is
GENMASK(4, 0), allowing 5-bit values up to 31. Will values greater than 15
be silently truncated here?

[ ... ]

> +static int mtk_pcie_sphy_get_one_cal_para(struct device *dev, const char *name, u8 max_val)
> +{
> +	u16 buf;
> +	u8 tmp;
> +	int ret;
> +
> +	/*
> +	 * All of the calibrations are always max 8 bits long, but some may
> +	 * be split between two different 8-bits cells: handle this corner
> +	 * case by retrying reading as u16.
> +	 */
> +	ret = nvmem_cell_read_u8(dev, name, &tmp);
> +	if (ret == 0)
> +		buf = tmp;
> +	else
> +		ret = nvmem_cell_read_u16(dev, name, &buf);
> +
> +	if (ret) {
> +		dev_err(dev, "Cannot get calibration data for %s: %d\n", name, ret);
> +		return ret;
> +	};

[Severity: Low]
Does this unconditionally log an error for expected missing cells (-ENOENT)
or during probe deferral (-EPROBE_DEFER)?

> +
> +	if (buf == 0) {
> +		dev_warn(dev, "No calibration for %s. Using defaults\n", name);
> +		return -ENOENT;
> +	}

[Severity: Medium]
Is 0 an invalid calibration value?

Later code checks if the calibration version is <= 4, which implies version
0 could exist. If a valid cell contains 0, will this mistakenly abort the
entire calibration process?

[ ... ]

> +static int mtk_pcie_sphy_get_calibration_data(struct mtk_pcie_sphy *pcie_sphy)
> +{

[ ... ]

> +	ret = mtk_pcie_sphy_get_one_cal_para(dev, "tx-ln0-rswn",
> +					     FIELD_MAX(RG_XTP_LN_TX_RSWN_IMPSEL));
> +	if (ret < 0)
> +		goto end;
> +	cal->tx_rswn_impsel[0] = ret;
> +
> +	ret = mtk_pcie_sphy_get_one_cal_para(dev, "tx-ln1-rswn",
> +					     FIELD_MAX(RG_XTP_LN_TX_RSWN_IMPSEL));
> +	if (ret < 0)
> +		goto end;
> +	cal->tx_rswn_impsel[1] = ret;

[Severity: Medium]
Will this break calibration on 1-lane PHYs?

If num_lanes is 1, the device tree might naturally omit lane 1 data. Would
the read for tx-ln1-rswn then return -ENOENT and cause all valid lane 0
calibration to be discarded?

[ ... ]

> +end:
> +	if (ret < 0) {
> +		/*
> +		 * If any of the calibration values is missing, or if there is
> +		 * no calibration at all in the eFuses, this is not a problem,
> +		 * as the PHY doesn't require one to actually work.
> +		 */
> +		if (ret == -ENOENT) {
> +			cal->supported = false;
> +			return 0;
> +		}
> +		return ret;
> +	};

[Severity: High]
If the kernel is compiled without CONFIG_NVMEM, nvmem_cell_read_u8 returns
-EOPNOTSUPP. Does this cause the entire PHY probe to fail on systems without
NVMEM, even though calibration is optional?

[ ... ]

> +static int mtk_pcie_sphy_probe(struct platform_device *pdev)
> +{

[ ... ]

> +	provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
> +	if (IS_ERR(provider))
> +		return dev_err_probe(dev, PTR_ERR(provider),
> +				     "Could not register PCI-Express S-PHY\n");
> +
> +	ret = devm_pm_runtime_enable(dev);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}

[Severity: Medium]
Could registering the PHY provider before enabling Runtime PM lead to a race
condition?

If a consumer driver probes concurrently and immediately calls phy_init(),
could it try to interact with the device before devm_pm_runtime_enable() has
completed?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260716151333.77254-1-angelogioacchino.delregno@collabora.com?part=2