[PATCH net-next v6 0/3] ptp: Add driver for R-Car Gen4

[PATCH net-next v6 0/3] ptp: Add driver for R-Car Gen4

[Niklas Söderlund]

Hello,

This series is the first part cleaning up how PTP timer support is
implemented on R-Car Gen4. Currently there is partial support for it in
some of the Ethernet devices that can use it, but not all.

The partial support have been implemented by hacking the gPTP module
directly into the first Ethernet device driver that used it, RTSN for
V4H and RSWITCH for S4. This is understandable as earlier R-Car
generations had a dedicated gPTP timer for each Ethernet device, but on
Gen4 there is a single system-wide PTP timer shared by all.

The current implementation makes it impossible for other Ethernet
devices on the platform to use the PTP timer without messing around with
other Ethernet device drivers.

The effort to clean this up starts with this series which adds the
system-wide gPTP timer as its own driver and device tree node.

This series will then be followed by work to add proper PTP support to
the R-Car RAVB Gen4 driver, which currently advertises to user-space it
supports PTP but which implementation is broken and does not work.

This will in turn be followed by work to the RTSN and RSWITCH drivers
will be be switched from its current partial support by mapping the gPTP
address space directly to instead use this driver.

Having both this and RTSN/RSWITCH described and enabled (!) in device
tree will not work as they will try to use the same memory region. For
this reason this new solution will only be enabled on platforms
after all user's of the gPTP clock have moved to only use the new
centralized timer. But in the interim both devices will be described
(but not enabled) in the platforms base dtsi file.

For some platforms this is straight forward, such as V4H Sparrow Hawk,
which only have the RAVB Ethernet interface. This platform currently
have no users of the PTP timer, but still advertise it supports it. This
and the soon to be posted RAVB patches solves that.

As the RAVB patches depends on this series the device tree node for the
gPTP clock is added in this series but will be enabled and linked to
consumers in the RAVB gPTP series for platforms where it will not
conflict with RTSN and RSWITCH. And further enabled as more of this is
cleaned up.

The gPTP driver itself is heavily influence by the existing partial
support for gPTP in the RTSN and RSWITCH drivers and the Renesas BSP.

Niklas Söderlund (3):
  dt-bindings: ptp: renesas,rcar-gen4-gptp: Add R-Car Gen4
  ptp: Add driver for R-Car Gen4
  arm64: dts: renesas: r8a779g0: Add gPTP node

 .../bindings/ptp/renesas,rcar-gen4-gptp.yaml  |  64 +++++
 MAINTAINERS                                   |   7 +
 arch/arm64/boot/dts/renesas/r8a779g0.dtsi     |   9 +
 drivers/ptp/Kconfig                           |  12 +
 drivers/ptp/Makefile                          |   1 +
 drivers/ptp/ptp_rcar_gen4.c                   | 225 ++++++++++++++++++
 6 files changed, 318 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/ptp/renesas,rcar-gen4-gptp.yaml
 create mode 100644 drivers/ptp/ptp_rcar_gen4.c

-- 
2.55.0

[PATCH net-next v6 1/3] dt-bindings: ptp: renesas,rcar-gen4-gptp: Add R-Car Gen4

[Niklas Söderlund]

Add bindings for the R-Car Gen4 gPTP timer. The timer enables accurate
synchronization of the clock in the control system. The timer is
system-wide and used by different Ethernet devices on each Gen4 platform.

  - On R-Car S4 it is shared between RSWITCH and RAVB.

  - On R-Car V4H it is shared between RTSN and RAVB.

  - On R-Car V4M it is only used by RAVB.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
---
* Changes since v1
- Drop 'binding for' for patch subject.
- Drop comment for renesas,rcar-gen4-gptp compatible to match other
  Renesas bindings.
- Drop unused label in example.
- Rename node ptp in example.
---
 .../bindings/ptp/renesas,rcar-gen4-gptp.yaml  | 64 +++++++++++++++++++
 MAINTAINERS                                   |  6 ++
 2 files changed, 70 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/ptp/renesas,rcar-gen4-gptp.yaml

diff --git a/Documentation/devicetree/bindings/ptp/renesas,rcar-gen4-gptp.yaml b/Documentation/devicetree/bindings/ptp/renesas,rcar-gen4-gptp.yaml
new file mode 100644
index 000000000000..3edd64d40038
--- /dev/null
+++ b/Documentation/devicetree/bindings/ptp/renesas,rcar-gen4-gptp.yaml
@@ -0,0 +1,64 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+# Copyright (C) 2026 Renesas Electronics Corp.
+# Copyright (C) 2026 Niklas Söderlund <niklas.soderlund@ragnatech.se>
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/ptp/renesas,rcar-gen4-gptp.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas R-Car Gen4 gPTP timer
+
+maintainers:
+  - Niklas Söderlund <niklas.soderlund@ragnatech.se>
+
+description:
+  The R-Car Gen4 gPTP timer enables accurate synchronization of the clock in
+  the control system. The timer is system-wide and used by different Ethernet
+  devices on each Gen4 platform.
+
+    - On R-Car S4 it is shared between RSWITCH and RAVB.
+    - On R-Car V4H it is shared between RTSN and RAVB.
+    - On R-Car V4M it is only used by RAVB.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - renesas,r8a779f0-gptp # S4-8
+          - renesas,r8a779g0-gptp # V4H
+          - renesas,r8a779h0-gptp # V4M
+      - const: renesas,rcar-gen4-gptp
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  power-domains:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - power-domains
+  - resets
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/r8a779g0-cpg-mssr.h>
+    #include <dt-bindings/power/r8a779g0-sysc.h>
+
+    ptp@e6449000 {
+            compatible = "renesas,r8a779g0-gptp", "renesas,rcar-gen4-gptp";
+            reg = <0xe6449000 0x500>;
+            clocks = <&cpg CPG_MOD 2723>;
+            power-domains = <&sysc R8A779G0_PD_ALWAYS_ON>;
+            resets = <&cpg 2723>;
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 932ea1db048e..ba83c5792c8c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -22941,6 +22941,12 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/mtd/renesas-nandc.yaml
 F:	drivers/mtd/nand/raw/renesas-nand-controller.c
 
+RENESAS R-CAR GEN4 GPTP DRIVER
+M:	Niklas Söderlund <niklas.soderlund@ragnatech.se>
+L:	linux-renesas-soc@vger.kernel.org
+S:	Supported
+F:	Documentation/devicetree/bindings/ptp/renesas,rcar-gen4-gptp.yaml
+
 RENESAS R-CAR GYROADC DRIVER
 M:	Marek Vasut <marek.vasut+renesas@mailbox.org>
 L:	linux-iio@vger.kernel.org
-- 
2.55.0

[PATCH net-next v6 2/3] ptp: Add driver for R-Car Gen4

[Niklas Söderlund]

Add driver for the gPTP timer found on R-Car Gen4 devices. The timer is
system-wide and shared by different Ethernet devices on each Gen4
platform. The operation of the timer is however not completely in
depended of the systems Ethernet devices.

  - On R-Car S4 is gated by the RSWITCH Ethernet module clock.

  - On R-Car V4H is gated by the RTSN Ethernet module clock.

  - On R-Car V4M is gated by its own module clock, the system have
    neither RTSN or RSWITCH device. But the module clock is the same as
    RTSN on V4H and the documentation referees to it as tsn (EtherTSN).

The gPTP device do have its own register space on all three platforms.
But on S4 and V4H it will share its clock and reset property with
RSWITCH or RTSN, respectively.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
---
* Changes since v5
- Use pm_runtime_resume_and_get() instead of pm_runtime_get_sync().

* Changes since v4
- Drop mod_devicetable.h include.
- Remove clap of register value as .max_adj prevents any overflow.

* Changes since v3
- Clamp increment calculated to register limitations.
- Check return value of clk_get_rate().
- Disable PM if ptp_clock_register() fails.
---
 MAINTAINERS                 |   1 +
 drivers/ptp/Kconfig         |  12 ++
 drivers/ptp/Makefile        |   1 +
 drivers/ptp/ptp_rcar_gen4.c | 225 ++++++++++++++++++++++++++++++++++++
 4 files changed, 239 insertions(+)
 create mode 100644 drivers/ptp/ptp_rcar_gen4.c

diff --git a/MAINTAINERS b/MAINTAINERS
index ba83c5792c8c..7b95b4ca41c2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -22946,6 +22946,7 @@ M:	Niklas Söderlund <niklas.soderlund@ragnatech.se>
 L:	linux-renesas-soc@vger.kernel.org
 S:	Supported
 F:	Documentation/devicetree/bindings/ptp/renesas,rcar-gen4-gptp.yaml
+F:	drivers/ptp/ptp_rcar_gen4.c
 
 RENESAS R-CAR GYROADC DRIVER
 M:	Marek Vasut <marek.vasut+renesas@mailbox.org>
diff --git a/drivers/ptp/Kconfig b/drivers/ptp/Kconfig
index b93640ca08b7..3593fd9da92a 100644
--- a/drivers/ptp/Kconfig
+++ b/drivers/ptp/Kconfig
@@ -263,4 +263,16 @@ config PTP_NETC_V4_TIMER
 	  synchronization. It also supports periodic output signal (e.g. PPS)
 	  and external trigger timestamping.
 
+config PTP_RCAR_GEN4
+	tristate "Renesas R-Car Gen4 PTP Driver"
+	depends on ARCH_RENESAS || COMPILE_TEST
+	depends on PTP_1588_CLOCK
+	help
+	  This driver adds support for using the Renesas R-Car Gen4 gPTP timer
+	  as a PTP clock, the clock can then be used by Gen4 Ethernet drivers
+	  for PTP time synchronization.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called ptp_rcar_gen4.
+
 endmenu
diff --git a/drivers/ptp/Makefile b/drivers/ptp/Makefile
index bdc47e284f14..0464a586bed2 100644
--- a/drivers/ptp/Makefile
+++ b/drivers/ptp/Makefile
@@ -22,3 +22,4 @@ obj-$(CONFIG_PTP_1588_CLOCK_OCP)	+= ptp_ocp.o
 obj-$(CONFIG_PTP_DFL_TOD)		+= ptp_dfl_tod.o
 obj-$(CONFIG_PTP_S390)			+= ptp_s390.o
 obj-$(CONFIG_PTP_NETC_V4_TIMER)		+= ptp_netc.o
+obj-$(CONFIG_PTP_RCAR_GEN4)		+= ptp_rcar_gen4.o
diff --git a/drivers/ptp/ptp_rcar_gen4.c b/drivers/ptp/ptp_rcar_gen4.c
new file mode 100644
index 000000000000..e82b6c5abc30
--- /dev/null
+++ b/drivers/ptp/ptp_rcar_gen4.c
@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Renesas R-Car Gen4 gPTP device driver
+ *
+ * Copyright (C) 2026 Renesas Electronics Corporation
+ * Copyright (C) 2026 Niklas Söderlund <niklas.soderlund@ragnatech.se>
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/ptp_clock_kernel.h>
+#include <linux/types.h>
+
+#define PTPTMEC_REG		0x0010
+#define PTPTMDC_REG		0x0014
+#define PTPTIVC0_REG		0x0020
+#define PTPTOVC00_REG		0x0030
+#define PTPTOVC10_REG		0x0034
+#define PTPTOVC20_REG		0x0038
+#define PTPGPTPTM00_REG		0x0050
+#define PTPGPTPTM10_REG		0x0054
+#define PTPGPTPTM20_REG		0x0058
+
+struct ptp_rcar_gen4_priv {
+	void __iomem *base;
+	struct clk *clk;
+
+	struct ptp_clock *clock;
+	struct ptp_clock_info info;
+
+	spinlock_t lock;	/* Registers access. */
+	s64 default_addend;
+};
+
+#define ptp_to_priv(ptp) container_of(ptp, struct ptp_rcar_gen4_priv, info)
+
+static int ptp_rcar_gen4_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
+{
+	struct ptp_rcar_gen4_priv *priv = ptp_to_priv(ptp);
+	s64 addend = priv->default_addend;
+	bool neg_adj = scaled_ppm < 0;
+	unsigned long flags;
+	s64 diff;
+
+	if (neg_adj)
+		scaled_ppm = -scaled_ppm;
+	diff = div_s64(addend * scaled_ppm_to_ppb(scaled_ppm), NSEC_PER_SEC);
+	addend = neg_adj ? addend - diff : addend + diff;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	iowrite32(addend, priv->base + PTPTIVC0_REG);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return 0;
+}
+
+static void _ptp_rcar_gen4_gettime(struct ptp_clock_info *ptp,
+				   struct timespec64 *ts)
+{
+	struct ptp_rcar_gen4_priv *priv = ptp_to_priv(ptp);
+
+	lockdep_assert_held(&priv->lock);
+
+	ts->tv_nsec = ioread32(priv->base + PTPGPTPTM00_REG);
+	ts->tv_sec = ioread32(priv->base + PTPGPTPTM10_REG) |
+		((s64)ioread32(priv->base + PTPGPTPTM20_REG) << 32);
+}
+
+static int ptp_rcar_gen4_gettime(struct ptp_clock_info *ptp,
+				 struct timespec64 *ts)
+{
+	struct ptp_rcar_gen4_priv *priv = ptp_to_priv(ptp);
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	_ptp_rcar_gen4_gettime(ptp, ts);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return 0;
+}
+
+static void _ptp_rcar_gen4_settime(struct ptp_clock_info *ptp,
+				   const struct timespec64 *ts)
+{
+	struct ptp_rcar_gen4_priv *priv = ptp_to_priv(ptp);
+
+	lockdep_assert_held(&priv->lock);
+
+	iowrite32(1, priv->base + PTPTMDC_REG);
+	iowrite32(0, priv->base + PTPTOVC20_REG);
+	iowrite32(0, priv->base + PTPTOVC10_REG);
+	iowrite32(0, priv->base + PTPTOVC00_REG);
+	iowrite32(1, priv->base + PTPTMEC_REG);
+	iowrite32(ts->tv_sec >> 32, priv->base + PTPTOVC20_REG);
+	iowrite32(ts->tv_sec, priv->base + PTPTOVC10_REG);
+	iowrite32(ts->tv_nsec, priv->base + PTPTOVC00_REG);
+}
+
+static int ptp_rcar_gen4_settime(struct ptp_clock_info *ptp,
+				 const struct timespec64 *ts)
+{
+	struct ptp_rcar_gen4_priv *priv = ptp_to_priv(ptp);
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	_ptp_rcar_gen4_settime(ptp, ts);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return 0;
+}
+
+static int ptp_rcar_gen4_adjtime(struct ptp_clock_info *ptp, s64 delta)
+{
+	struct ptp_rcar_gen4_priv *priv = ptp_to_priv(ptp);
+	struct timespec64 ts;
+	unsigned long flags;
+	s64 now;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	_ptp_rcar_gen4_gettime(ptp, &ts);
+	now = ktime_to_ns(timespec64_to_ktime(ts));
+	ts = ns_to_timespec64(now + delta);
+	_ptp_rcar_gen4_settime(ptp, &ts);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return 0;
+}
+
+static struct ptp_clock_info ptp_rcar_gen4_info = {
+	.owner = THIS_MODULE,
+	.name = "R-Car Gen4 gPTP",
+	.max_adj = 50000000,
+	.adjfine = ptp_rcar_gen4_adjfine,
+	.adjtime = ptp_rcar_gen4_adjtime,
+	.gettime64 = ptp_rcar_gen4_gettime,
+	.settime64 = ptp_rcar_gen4_settime,
+};
+
+static int ptp_rcar_gen4_probe(struct platform_device *pdev)
+{
+	struct ptp_rcar_gen4_priv *priv;
+	struct device *dev = &pdev->dev;
+	unsigned long rate;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, priv);
+
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	priv->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(priv->clk))
+		return PTR_ERR(priv->clk);
+
+	rate = clk_get_rate(priv->clk);
+	if (!rate)
+		return -ENODEV;
+
+	spin_lock_init(&priv->lock);
+
+	priv->info = ptp_rcar_gen4_info;
+
+	/* Default timer increment in ns.
+	 * bit[31:27] - integer
+	 * bit[26:0]  - decimal
+	 * increment[ns] = perid[ns] * 2^27 => (1ns * 2^27) / rate[hz]
+	 */
+
+	priv->default_addend = div_s64(1000000000LL << 27, rate);
+
+	pm_runtime_enable(dev);
+	pm_runtime_resume_and_get(dev);
+
+	iowrite32(priv->default_addend, priv->base + PTPTIVC0_REG);
+	iowrite32(1, priv->base + PTPTMEC_REG);
+
+	priv->clock = ptp_clock_register(&priv->info, dev);
+	if (IS_ERR(priv->clock)) {
+		pm_runtime_put_sync(dev);
+		pm_runtime_disable(dev);
+		return PTR_ERR(priv->clock);
+	}
+
+	return 0;
+}
+
+static void ptp_rcar_gen4_remove(struct platform_device *pdev)
+{
+	struct ptp_rcar_gen4_priv *priv = platform_get_drvdata(pdev);
+	struct device *dev = &pdev->dev;
+
+	ptp_clock_unregister(priv->clock);
+
+	iowrite32(1, priv->base + PTPTMDC_REG);
+
+	pm_runtime_put_sync(dev);
+	pm_runtime_disable(dev);
+}
+
+static const struct of_device_id ptp_rcar_gen4_of_match[] = {
+	{ .compatible = "renesas,rcar-gen4-gptp", },
+	{ /* Sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, ptp_rcar_gen4_of_match);
+
+static struct platform_driver ptp_rcar_gen4_driver = {
+	.driver = {
+		.name = "ptp-rcar-gen4",
+		.of_match_table = ptp_rcar_gen4_of_match,
+	},
+	.probe    = ptp_rcar_gen4_probe,
+	.remove   = ptp_rcar_gen4_remove,
+};
+module_platform_driver(ptp_rcar_gen4_driver);
+
+MODULE_AUTHOR("Niklas Söderlund");
+MODULE_DESCRIPTION("Renesas R-Car Gen4 gPTP driver");
+MODULE_LICENSE("GPL");
-- 
2.55.0

[PATCH net-next v6 3/3] arm64: dts: renesas: r8a779g0: Add gPTP node

[Niklas Söderlund]

The gPTP module is shared between the RAVB and RTSN Ethernet devices on
the SoC.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
---
* Changes since v2
- Preserve sort order by unit-address.

* Changes since v1
- Rename node ptp.
---
 arch/arm64/boot/dts/renesas/r8a779g0.dtsi | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/arm64/boot/dts/renesas/r8a779g0.dtsi b/arch/arm64/boot/dts/renesas/r8a779g0.dtsi
index 82a7278836e5..b9b860ef7035 100644
--- a/arch/arm64/boot/dts/renesas/r8a779g0.dtsi
+++ b/arch/arm64/boot/dts/renesas/r8a779g0.dtsi
@@ -589,6 +589,15 @@ tmu4: timer@ffc00000 {
 			status = "disabled";
 		};
 
+		gptp: ptp@e6449000 {
+			compatible = "renesas,r8a779g0-gptp", "renesas,rcar-gen4-gptp";
+			reg = <0 0xe6449000 0 0x500>;
+			clocks = <&cpg CPG_MOD 2723>;
+			power-domains = <&sysc R8A779G0_PD_ALWAYS_ON>;
+			resets = <&cpg 2723>;
+			status = "disabled";
+		};
+
 		tsn0: ethernet@e6460000 {
 			compatible = "renesas,r8a779g0-ethertsn", "renesas,rcar-gen4-ethertsn";
 			reg = <0 0xe6460000 0 0x7000>,
-- 
2.55.0

Re: [PATCH net-next v6 1/3] dt-bindings: ptp: renesas,rcar-gen4-gptp: Add R-Car Gen4

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The standalone gPTP node will cause overlapping memory regions or schema validation failures due to conflicts with existing ethernet bindings.
--

--- Patch [1]: [PATCH net-next v6 1/3] dt-bindings: ptp: renesas,rcar-gen4-gptp: Add R-Car Gen4 ---
commit 1e91aef0621f1bc3f4049383c20bf5b76369d35b
Author: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

dt-bindings: ptp: renesas,rcar-gen4-gptp: Add R-Car Gen4
    
This commit adds device tree bindings for the R-Car Gen4 gPTP timer. The
timer enables accurate clock synchronization and is shared among Ethernet
devices like RSWITCH, RAVB, and RTSN depending on the specific Gen4 platform.

> diff --git a/Documentation/devicetree/bindings/ptp/renesas,rcar-gen4-gptp.yaml b/Documentation/devicetree/bindings/ptp/renesas,rcar-gen4-gptp.yaml
> new file mode 100644
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/ptp/renesas,rcar-gen4-gptp.yaml
[ ... ]
> +properties:
> +  compatible:
> +    items:
> +      - enum:
> +          - renesas,r8a779f0-gptp # S4-8
> +          - renesas,r8a779g0-gptp # V4H
> +          - renesas,r8a779h0-gptp # V4M
> +      - const: renesas,rcar-gen4-gptp
> +
> +  reg:
> +    maxItems: 1

[Severity: High]
Does defining this standalone MMIO region for the gPTP timer conflict with the
already-claimed gptp region required by the established Gen4 ethernet bindings?

If a new standalone gPTP node maps the 0xe6449000 MMIO region on R-Car V4H as
intended, it will overlap with the existing renesas,ethertsn.yaml binding
which explicitly requires the gptp region (mapping the exact same address) in
its reg-names.

Defining both nodes in the device tree could result in overlapping memory
regions and cause runtime probe failures (-EBUSY).

If the overlap is resolved by removing the region from the ethernet node,
wouldn't dt_binding_check fail because renesas,ethertsn.yaml was not updated
in this patch series to make the gptp region optional or deprecated?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260803095232.3527111-1-niklas.soderlund+renesas@ragnatech.se?part=1

Re: [PATCH net-next v6 2/3] ptp: Add driver for R-Car Gen4

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 4 potential issue(s) to consider:
- [High] The driver ignores the return value of `pm_runtime_resume_and_get()`, risking unpowered hardware accesses and unbalanced PM usage counters.
- [High] The `_ptp_rcar_gen4_settime()` function briefly configures the shared timer with 0 offsets while it is enabled, exposing erroneous timestamps to all sharing Ethernet devices.
- [Medium] The hardware timer is left enabled and running if `ptp_clock_register()` fails during probe.
- [Medium] Passing an `unsigned long` clock rate to `div_s64()` can cause a sign truncation bug if the clock rate is sufficiently high.
--

--- Patch [2]: [PATCH net-next v6 2/3] ptp: Add driver for R-Car Gen4 ---
commit 447a3dd2732c6247d6f684bcaa7abcce33006d04
Author: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

ptp: Add driver for R-Car Gen4

Add driver for the gPTP timer found on R-Car Gen4 devices. The timer is
system-wide and shared by different Ethernet devices on each Gen4
platform.

> diff --git a/drivers/ptp/ptp_rcar_gen4.c b/drivers/ptp/ptp_rcar_gen4.c
> new file mode 100644
> index 0000000000000..e82b6c5abc306
> --- /dev/null
> +++ b/drivers/ptp/ptp_rcar_gen4.c

[ ... ]

> +static void _ptp_rcar_gen4_settime(struct ptp_clock_info *ptp,
> +				   const struct timespec64 *ts)
> +{
> +	struct ptp_rcar_gen4_priv *priv = ptp_to_priv(ptp);
> +
> +	lockdep_assert_held(&priv->lock);
> +
> +	iowrite32(1, priv->base + PTPTMDC_REG);
> +	iowrite32(0, priv->base + PTPTOVC20_REG);
> +	iowrite32(0, priv->base + PTPTOVC10_REG);
> +	iowrite32(0, priv->base + PTPTOVC00_REG);
> +	iowrite32(1, priv->base + PTPTMEC_REG);
> +	iowrite32(ts->tv_sec >> 32, priv->base + PTPTOVC20_REG);
> +	iowrite32(ts->tv_sec, priv->base + PTPTOVC10_REG);
> +	iowrite32(ts->tv_nsec, priv->base + PTPTOVC00_REG);

[Severity: High]
Could this expose a window where the hardware runs with zeroed offsets?

The timer is enabled by writing to PTPTMEC_REG before the actual time offsets
are written to the PTPTOVC* registers. Since this timer is shared across the
system, could this brief window result in bogus timestamps being generated for
connected Ethernet devices?

Should the timer be enabled after the new offsets are written?

> +}

[ ... ]

> +static int ptp_rcar_gen4_probe(struct platform_device *pdev)
> +{

[ ... ]

> +	/* Default timer increment in ns.
> +	 * bit[31:27] - integer
> +	 * bit[26:0]  - decimal
> +	 * increment[ns] = perid[ns] * 2^27 => (1ns * 2^27) / rate[hz]
> +	 */
> +
> +	priv->default_addend = div_s64(1000000000LL << 27, rate);

[Severity: Medium]
Is it safe to pass the unsigned long rate to div_s64()?

Since div_s64() expects an s32 divisor, could this cause a sign truncation
regression if the clock rate exceeds INT_MAX (2.147 GHz), resulting in a
negative default_addend calculation?

Should this use div64_ul() or div_u64() instead to prevent unintended
truncation?

> +
> +	pm_runtime_enable(dev);
> +	pm_runtime_resume_and_get(dev);

[Severity: High]
Is it safe to ignore the return value of pm_runtime_resume_and_get()?

If the device fails to power on and returns a negative error code, the driver
proceeds to access hardware via the iowrite32() calls below, which could lead
to an asynchronous external abort and system crash on ARM platforms.

Additionally, if it fails, the usage counter isn't incremented. Would the
unconditional pm_runtime_put_sync() calls in the error path below and in
ptp_rcar_gen4_remove() cause a PM usage counter underflow?

> +
> +	iowrite32(priv->default_addend, priv->base + PTPTIVC0_REG);
> +	iowrite32(1, priv->base + PTPTMEC_REG);
> +
> +	priv->clock = ptp_clock_register(&priv->info, dev);
> +	if (IS_ERR(priv->clock)) {
> +		pm_runtime_put_sync(dev);
> +		pm_runtime_disable(dev);
> +		return PTR_ERR(priv->clock);
> +	}

[Severity: Medium]
If ptp_clock_register() fails, does this error path leave the hardware timer
running?

The timer is started just above this check by writing to PTPTMEC_REG, but
unlike ptp_rcar_gen4_remove(), this path doesn't write to PTPTMDC_REG to
disable it. Could this leak hardware resources and prevent the PM domain from
cleanly suspending?

> +
> +	return 0;
> +}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260803095232.3527111-1-niklas.soderlund+renesas@ragnatech.se?part=2

Re: [PATCH net-next v6 3/3] arm64: dts: renesas: r8a779g0: Add gPTP node

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Device Tree Resource Conflict: Overlapping memory regions for gptp and tsn0 nodes will cause -EBUSY probe failures.
--

--- Patch [3]: [PATCH net-next v6 3/3] arm64: dts: renesas: r8a779g0: Add gPTP node ---
commit bb4e1d1111c141906839e9f11b82a931aa6c6fd6
Author: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

arm64: dts: renesas: r8a779g0: Add gPTP node

This commit adds a new gPTP node to the r8a779g0 device tree, sharing the
module between the RAVB and RTSN Ethernet devices on the SoC.

> diff --git a/arch/arm64/boot/dts/renesas/r8a779g0.dtsi b/arch/arm64/boot/dts/renesas/r8a779g0.dtsi
> index 82a7278836e57..b9b860ef70351 100644
> --- a/arch/arm64/boot/dts/renesas/r8a779g0.dtsi
> +++ b/arch/arm64/boot/dts/renesas/r8a779g0.dtsi

[ ... ]

> @@ -589,6 +589,15 @@ tmu4: timer@ffc00000 {
>  			status = "disabled";
>  		};
>  
> +		gptp: ptp@e6449000 {
> +			compatible = "renesas,r8a779g0-gptp", "renesas,rcar-gen4-gptp";
> +			reg = <0 0xe6449000 0 0x500>;
> +			clocks = <&cpg CPG_MOD 2723>;
> +			power-domains = <&sysc R8A779G0_PD_ALWAYS_ON>;
> +			resets = <&cpg 2723>;
> +			status = "disabled";
> +		};
> +
>  		tsn0: ethernet@e6460000 {
>  			compatible = "renesas,r8a779g0-ethertsn", "renesas,rcar-gen4-ethertsn";
>  			reg = <0 0xe6460000 0 0x7000>,

[Severity: Medium]
Will this overlapping memory region cause a resource conflict during probe?

The new gptp node maps the memory region at 0xe6449000. However, the existing
tsn0 node directly below it already claims this exact same region in its reg
property:

arch/arm64/boot/dts/renesas/r8a779g0.dtsi:tsn0: ethernet@e6460000 {
            reg = <0 0xe6460000 0 0x7000>,
                  <0 0xe6449000 0 0x500>;
            reg-names = "tsnes", "gptp";

If a board file enables both the tsn0 and gptp nodes, whichever driver probes
second is likely to fail with an -EBUSY error because request_mem_region()
enforces exclusive access.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260803095232.3527111-1-niklas.soderlund+renesas@ragnatech.se?part=3