[PATCH v12 0/3] Raspberry Pi 5 RTC driver

[PATCH v12 0/3] Raspberry Pi 5 RTC driver

[Sander Speetjens]

The Raspberry Pi 5 has a battery-backed RTC located
on the DA9091 PMIC accessed via the I2C bus[1].
Access to the RTC is provided exclusively through the VideoCore firmware
mailbox interface (not via a direct I2C register interface).

As stated by jamesh on the Rasperry Pi forum [2],
"There are no plans to release a public datasheet for the DA9091."
So we are stuck with the firmware interface for now.
PhilE also states that "The firmware needs full control of the DA9091,
sometimes with extremely low latency,
otherwise there's a risk the supply could just cut the power."

This series adds:
  - a DT property for the charging voltage of the RTC battery
  - the RTC driver that talks to the firmware

The driver and binding are based on (and largely taken from) the
downstream Raspberry Pi kernel. The main changes for upstream are
the addition of a dt binding property for setting the charging voltage and
binding the driver from the raspberrypi-firmware driver instead of from
the DT.

The driver supports time read/write, alarm, and optional trickle
charging voltage configuration via the device-tree.

Testing
- Hardware: Raspberry Pi 5 Model B revC
- Kernel: v7.2
- dt_binding_check: passed
- Basic RTC operations (read/write time, alarm) verified

[1] https://www.raspberrypi.com/news/introducing-raspberry-pi-5/
[2] https://forums.raspberrypi.com/viewtopic.php?t=359073

Sander Speetjens (3):
  dt-bindings: rtc: Add missing type to trickle-voltage-millivolt
  dt-bindings: rtc: Add property for Raspberry Pi 5 RTC
  rtc: Add Raspberry Pi 5 RTC driver

 .../arm/bcm/raspberrypi,bcm2835-firmware.yaml |   6 +
 .../devicetree/bindings/rtc/rtc.yaml          |   1 +
 drivers/firmware/raspberrypi.c                |  24 ++
 drivers/rtc/Kconfig                           |  12 +
 drivers/rtc/Makefile                          |   1 +
 drivers/rtc/rtc-raspberrypi.c                 | 278 ++++++++++++++++++
 include/soc/bcm2835/raspberrypi-firmware.h    |   2 +
 7 files changed, 324 insertions(+)
 create mode 100644 drivers/rtc/rtc-raspberrypi.c


base-commit: 72d3fcf802c45d00b300f25b848a93c3a2bd7c7e
-- 
2.56.0

[PATCH v12 1/3] dt-bindings: rtc: Add missing type to trickle-voltage-millivolt

[Sander Speetjens]

The trickle-voltage-millivolt property had no associated type.
-millivolt is not a default property unit suffix, so the schema does
not automatically infer uint32. Explicitly reference the uint32
definition so the type is correctly declared.

Suggested-by: Rob Herring <robh@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Sander Speetjens <sander.speetjens@gmail.com>
---
V11 -> V12: No changes

V11: https://lore.kernel.org/linux-rtc/20261014083016.332338-1-sander.speetjens@gmail.com

 Documentation/devicetree/bindings/rtc/rtc.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/rtc/rtc.yaml b/Documentation/devicetree/bindings/rtc/rtc.yaml
index efb66df82782..e46d50b1063e 100644
--- a/Documentation/devicetree/bindings/rtc/rtc.yaml
+++ b/Documentation/devicetree/bindings/rtc/rtc.yaml
@@ -51,6 +51,7 @@ properties:
       if trickle charger should be enabled.
 
   trickle-voltage-millivolt:
+    $ref: /schemas/types.yaml#/definitions/uint32
     description:
       Selected voltage for trickle charger. Should be given
       if trickle charger should be enabled and the trickle voltage is different
-- 
2.56.0

[PATCH v12 2/3] dt-bindings: rtc: Add property for Raspberry Pi 5 RTC

[Sander Speetjens]

The Raspberry Pi 5 has a built-in RTC that can be battery-backed
via the VBAT pin. When a rechargeable coin cell is used, the
hardware requires a trickle-charge voltage to keep the battery
topped up.

Expose the trickle-voltage-millivolt DT property so the driver can
program the correct charge voltage for board specific configurations with
the attached battery.

The property is added to the existing raspberrypi,bcm2835-firmware
binding (rather than creating a new RTC node) because the RTC is
accessed exclusively through the firmware mailbox interface.
We only $ref the individual property from rtc.yaml and do not
reference the full schema, because the firmware node name does not
match the $nodename pattern required by rtc.yaml.

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Sander Speetjens <sander.speetjens@gmail.com>
---
V11 -> V12: No changes

V11: https://lore.kernel.org/linux-rtc/20261014083016.332338-1-sander.speetjens@gmail.com

 .../bindings/arm/bcm/raspberrypi,bcm2835-firmware.yaml      | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/arm/bcm/raspberrypi,bcm2835-firmware.yaml b/Documentation/devicetree/bindings/arm/bcm/raspberrypi,bcm2835-firmware.yaml
index 983ea80eaec9..dc71fd57834e 100644
--- a/Documentation/devicetree/bindings/arm/bcm/raspberrypi,bcm2835-firmware.yaml
+++ b/Documentation/devicetree/bindings/arm/bcm/raspberrypi,bcm2835-firmware.yaml
@@ -133,6 +133,11 @@ properties:
     required:
       - compatible
 
+  trickle-voltage-millivolt:
+    $ref: /schemas/rtc/rtc.yaml#/properties/trickle-voltage-millivolt
+    minimum: 1300
+    maximum: 5000
+
 required:
   - compatible
   - mboxes
@@ -144,6 +149,7 @@ examples:
     firmware {
         compatible = "raspberrypi,bcm2835-firmware", "simple-mfd";
         mboxes = <&mailbox>;
+        trickle-voltage-millivolt = <3300>;
 
         firmware_clocks: clocks {
             compatible = "raspberrypi,firmware-clocks";
-- 
2.56.0

[PATCH v12 3/3] rtc: Add Raspberry Pi 5 RTC driver

[Sander Speetjens]

Upstreaming the downstream Raspberry Pi 5 RTC driver.
This driver supports the custom DA9091,
which is accessed through the firmware mailbox.

Based on code originally written by Jonathan Bell
<jonathan@raspberrypi.com>
and Dom Cobley <popcornmix@gmail.com>

Reviewed-by: Stefan Wahren <wahrenst@gmx.net>
Signed-off-by: Sander Speetjens <sander.speetjens@gmail.com>
---
V11 -> V12:
- Remove unused var in firmware
- Clear pending alarms before setting a new one 

V11: https://lore.kernel.org/linux-rtc/20261014083016.332338-1-sander.speetjens@gmail.com

 drivers/firmware/raspberrypi.c             |  24 ++
 drivers/rtc/Kconfig                        |  12 +
 drivers/rtc/Makefile                       |   1 +
 drivers/rtc/rtc-raspberrypi.c              | 278 +++++++++++++++++++++
 include/soc/bcm2835/raspberrypi-firmware.h |   2 +
 5 files changed, 317 insertions(+)
 create mode 100644 drivers/rtc/rtc-raspberrypi.c

diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c
index 0aa322e9a2e7..443459c8c90f 100644
--- a/drivers/firmware/raspberrypi.c
+++ b/drivers/firmware/raspberrypi.c
@@ -24,6 +24,7 @@
 
 static struct platform_device *rpi_hwmon;
 static struct platform_device *rpi_clk;
+static struct platform_device *rpi_rtc;
 
 struct rpi_firmware {
 	struct mbox_client cl;
@@ -231,6 +232,26 @@ static void rpi_register_clk_driver(struct device *dev)
 						-1, NULL, 0);
 }
 
+static void rpi_register_rtc_driver(struct device *dev)
+{
+	struct platform_device *pdev;
+
+	/*
+	 * Check if our model of Raspberry Pi board is from the 5th gen
+	 * as the RTC is only present on that model.
+	 */
+	if (!of_machine_is_compatible("brcm,bcm2712"))
+		return;
+
+	pdev = platform_device_register_data(dev, "raspberrypi-rtc",
+					     -1, NULL, 0);
+
+	if (IS_ERR(pdev))
+		return;
+
+	rpi_rtc = pdev;
+}
+
 unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw, unsigned int id)
 {
 	struct rpi_firmware_clk_rate_request msg =
@@ -305,6 +326,7 @@ static int rpi_firmware_probe(struct platform_device *pdev)
 	rpi_firmware_print_firmware_revision(fw);
 	rpi_register_hwmon_driver(dev, fw);
 	rpi_register_clk_driver(dev);
+	rpi_register_rtc_driver(dev);
 
 	return 0;
 }
@@ -327,6 +349,8 @@ static void rpi_firmware_remove(struct platform_device *pdev)
 	rpi_hwmon = NULL;
 	platform_device_unregister(rpi_clk);
 	rpi_clk = NULL;
+	platform_device_unregister(rpi_rtc);
+	rpi_rtc = NULL;
 
 	rpi_firmware_put(fw);
 }
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 05b9233b9418..6adaf425a76b 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1999,6 +1999,18 @@ config RTC_DRV_R7301
 	   This driver can also be built as a module. If so, the module
 	   will be called rtc-r7301.
 
+config RTC_DRV_RPI
+	tristate "Raspberry Pi RTC"
+	depends on RASPBERRYPI_FIRMWARE || (COMPILE_TEST && !RASPBERRYPI_FIRMWARE)
+	depends on ARCH_BRCMSTB || COMPILE_TEST
+	default ARCH_BRCMSTB
+	help
+	  If you say yes here you get support for the RTC found on
+	  Raspberry Pi 5th gen devices.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-raspberrypi.
+
 config RTC_DRV_STM32
 	tristate "STM32 RTC"
 	select REGMAP_MMIO
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 0347645b021f..46f1a0fc2416 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -144,6 +144,7 @@ obj-$(CONFIG_RTC_DRV_PS3)	+= rtc-ps3.o
 obj-$(CONFIG_RTC_DRV_PXA)	+= rtc-pxa.o
 obj-$(CONFIG_RTC_DRV_R7301)	+= rtc-r7301.o
 obj-$(CONFIG_RTC_DRV_R9701)	+= rtc-r9701.o
+obj-$(CONFIG_RTC_DRV_RPI)	+= rtc-raspberrypi.o
 obj-$(CONFIG_RTC_DRV_RC5T583)	+= rtc-rc5t583.o
 obj-$(CONFIG_RTC_DRV_RC5T619)	+= rtc-rc5t619.o
 obj-$(CONFIG_RTC_DRV_RK808)	+= rtc-rk808.o
diff --git a/drivers/rtc/rtc-raspberrypi.c b/drivers/rtc/rtc-raspberrypi.c
new file mode 100644
index 000000000000..4b55b887b4aa
--- /dev/null
+++ b/drivers/rtc/rtc-raspberrypi.c
@@ -0,0 +1,278 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+/**
+ * rtc-raspberrypi.c
+ *
+ * RTC driver using firmware mailbox
+ * Supports battery backed RTC and wake alarms
+ *
+ * Based on rtc-meson-vrtc by Neil Armstrong
+ *
+ * Copyright (c) 2023, Raspberry Pi Ltd.
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/of.h>
+#include <soc/bcm2835/raspberrypi-firmware.h>
+
+#define	RTC_TIME		0
+#define	RTC_ALARM		1
+#define	RTC_ALARM_PENDING	2
+#define	RTC_ALARM_ENABLE	3
+#define	RTC_BBAT_CHG_VOLTS	4
+#define	RTC_BBAT_CHG_VOLTS_MIN	5
+#define	RTC_BBAT_CHG_VOLTS_MAX	6
+#define	RTC_BBAT_VOLTS		7
+
+struct rpi_rtc_data {
+	struct rtc_device *rtc;
+	struct rpi_firmware *fw;
+	u32 bbat_vchg_millivolts;
+	u32 bbat_vchg_min_millivolts;
+	u32 bbat_vchg_max_millivolts;
+};
+
+struct rpi_rtc_reg {
+	__le32 reg;
+	__le32 val;
+} __packed;
+
+static int rpi_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct rpi_rtc_data *rtc = dev_get_drvdata(dev);
+	struct rpi_rtc_reg data = {
+		.reg = cpu_to_le32(RTC_TIME)
+	};
+	int err;
+
+	err = rpi_firmware_property(rtc->fw, RPI_FIRMWARE_GET_RTC_REG,
+				    &data, sizeof(data));
+	rtc_time64_to_tm(le32_to_cpu(data.val), tm);
+	return err;
+}
+
+static int rpi_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct rpi_rtc_data *rtc = dev_get_drvdata(dev);
+	struct rpi_rtc_reg data = {
+		.reg = cpu_to_le32(RTC_TIME),
+		.val = cpu_to_le32(rtc_tm_to_time64(tm))
+	};
+
+	return rpi_firmware_property(rtc->fw, RPI_FIRMWARE_SET_RTC_REG,
+				     &data, sizeof(data));
+}
+
+static int rpi_rtc_alarm_irq_is_enabled(struct device *dev, unsigned char *enabled)
+{
+	struct rpi_rtc_data *rtc = dev_get_drvdata(dev);
+	struct rpi_rtc_reg data = {
+		.reg = cpu_to_le32(RTC_ALARM_ENABLE)
+	};
+	int err;
+
+	err = rpi_firmware_property(rtc->fw, RPI_FIRMWARE_GET_RTC_REG,
+				    &data, sizeof(data));
+	*enabled = le32_to_cpu(data.val) & 0x1;
+	return err;
+}
+
+static int rpi_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct rpi_rtc_data *rtc = dev_get_drvdata(dev);
+	struct rpi_rtc_reg data = {
+		.reg = cpu_to_le32(RTC_ALARM_ENABLE),
+		.val = cpu_to_le32(enabled)
+	};
+
+	return rpi_firmware_property(rtc->fw, RPI_FIRMWARE_SET_RTC_REG,
+				     &data, sizeof(data));
+}
+
+static int rpi_rtc_alarm_clear_pending(struct device *dev)
+{
+	struct rpi_rtc_data *rtc = dev_get_drvdata(dev);
+	struct rpi_rtc_reg data = {
+		.reg = cpu_to_le32(RTC_ALARM_PENDING),
+		.val = cpu_to_le32(1)
+	};
+
+	return rpi_firmware_property(rtc->fw, RPI_FIRMWARE_SET_RTC_REG,
+				     &data, sizeof(data));
+}
+
+static int rpi_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+	struct rpi_rtc_data *rtc = dev_get_drvdata(dev);
+	struct rpi_rtc_reg data = {
+		.reg = cpu_to_le32(RTC_ALARM)
+	};
+	int err;
+
+	err = rpi_rtc_alarm_irq_is_enabled(dev, &alarm->enabled);
+	if (!err)
+		err = rpi_firmware_property(rtc->fw, RPI_FIRMWARE_GET_RTC_REG,
+					    &data, sizeof(data));
+	rtc_time64_to_tm(le32_to_cpu(data.val), &alarm->time);
+
+	return err;
+}
+
+static int rpi_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+	struct rpi_rtc_data *rtc = dev_get_drvdata(dev);
+	struct rpi_rtc_reg data = {
+		.reg = cpu_to_le32(RTC_ALARM),
+		.val = cpu_to_le32(rtc_tm_to_time64(&alarm->time))
+	};
+	int err;
+
+	err = rpi_rtc_alarm_clear_pending(dev);
+
+	if (!err)
+		err = rpi_firmware_property(rtc->fw, RPI_FIRMWARE_SET_RTC_REG,
+					    &data, sizeof(data));
+
+	if (!err)
+		err = rpi_rtc_alarm_irq_enable(dev, alarm->enabled);
+
+	return err;
+}
+
+static const struct rtc_class_ops rpi_rtc_ops = {
+	.read_time = rpi_rtc_read_time,
+	.set_time = rpi_rtc_set_time,
+	.read_alarm = rpi_rtc_read_alarm,
+	.set_alarm = rpi_rtc_set_alarm,
+	.alarm_irq_enable = rpi_rtc_alarm_irq_enable,
+};
+
+static void rpi_rtc_set_limits(struct device *dev)
+{
+	struct rpi_rtc_data *rtc = dev_get_drvdata(dev);
+	struct rpi_rtc_reg data = {
+		.reg = cpu_to_le32(RTC_BBAT_CHG_VOLTS_MIN)
+	};
+
+	int err = rpi_firmware_property(rtc->fw, RPI_FIRMWARE_GET_RTC_REG,
+					&data, sizeof(data));
+	if (!err)
+		rtc->bbat_vchg_min_millivolts = le32_to_cpu(data.val) / 1000U;
+	else
+		dev_warn(dev, "failed to get minimum trickle charge voltage\n");
+
+	data.reg = cpu_to_le32(RTC_BBAT_CHG_VOLTS_MAX);
+	data.val = cpu_to_le32(0);
+	err = rpi_firmware_property(rtc->fw, RPI_FIRMWARE_GET_RTC_REG,
+				    &data, sizeof(data));
+	if (!err)
+		rtc->bbat_vchg_max_millivolts = le32_to_cpu(data.val) / 1000U;
+	else
+		dev_warn(dev, "failed to get maximum trickle charge voltage\n");
+}
+
+static void rpi_rtc_set_charge_voltage(struct device *dev)
+{
+	struct rpi_rtc_data *rtc = dev_get_drvdata(dev);
+	struct rpi_rtc_reg data = {
+		.reg = cpu_to_le32(RTC_BBAT_CHG_VOLTS),
+		.val = cpu_to_le32(rtc->bbat_vchg_millivolts * 1000U)
+	};
+	int err;
+
+	if (rtc->bbat_vchg_millivolts != 0 &&
+	    (rtc->bbat_vchg_millivolts < rtc->bbat_vchg_min_millivolts ||
+	    rtc->bbat_vchg_millivolts > rtc->bbat_vchg_max_millivolts)) {
+		dev_warn(dev, "trickle charge voltage %umV is outside of the supported range (%umV - %umV)\n",
+			 rtc->bbat_vchg_millivolts,
+			 rtc->bbat_vchg_min_millivolts,
+			 rtc->bbat_vchg_max_millivolts);
+		return;
+	}
+
+	err = rpi_firmware_property(rtc->fw, RPI_FIRMWARE_SET_RTC_REG,
+				    &data, sizeof(data));
+
+	if (err)
+		dev_err(dev, "failed to set trickle charge voltage to %umV: %d\n",
+			rtc->bbat_vchg_millivolts, err);
+	else if (rtc->bbat_vchg_millivolts)
+		dev_info(dev, "trickle charging enabled at %umV\n",
+			 rtc->bbat_vchg_millivolts);
+}
+
+static int rpi_rtc_probe(struct platform_device *pdev)
+{
+	struct rpi_rtc_data *rtc;
+	struct device *dev = &pdev->dev;
+	struct rpi_firmware *firmware;
+	int ret;
+
+	// Get the firmware device from the parent device
+	firmware = devm_rpi_firmware_get(dev, dev->parent->of_node);
+
+	if (!firmware)
+		return -EPROBE_DEFER;
+
+	rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL);
+	if (!rtc)
+		return -ENOMEM;
+
+	rtc->fw = firmware;
+
+	ret = devm_device_init_wakeup(dev);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, rtc);
+
+	rtc->rtc = devm_rtc_allocate_device(dev);
+	if (IS_ERR(rtc->rtc))
+		return PTR_ERR(rtc->rtc);
+
+	rtc->rtc->range_max = U32_MAX;           /* 2106-02-07 */
+
+	set_bit(RTC_FEATURE_ALARM_WAKEUP_ONLY, rtc->rtc->features);
+	clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->rtc->features);
+
+	rtc->rtc->ops = &rpi_rtc_ops;
+
+	rpi_rtc_alarm_clear_pending(dev);
+
+	/*
+	 * The trickle-voltage property lives on the parent firmware node
+	 * because we deliberately do not create a DT child node just to
+	 * instantiate this driver (see DT maintainer guidance).
+	 * The firmware driver registers us as a platform device at runtime.
+	 */
+	rtc->bbat_vchg_millivolts = 0;
+	of_property_read_u32(dev->parent->of_node, "trickle-voltage-millivolt",
+			     &rtc->bbat_vchg_millivolts);
+
+	rpi_rtc_set_limits(dev);
+	rpi_rtc_set_charge_voltage(dev);
+
+	return devm_rtc_register_device(rtc->rtc);
+}
+
+static const struct platform_device_id raspberrypi_rtc_id[] = {
+	{ "raspberrypi-rtc" },
+	{ }
+};
+MODULE_DEVICE_TABLE(platform, raspberrypi_rtc_id);
+
+static struct platform_driver rpi_rtc_driver = {
+	.driver = {
+		.name = "raspberrypi-rtc",
+	},
+	.id_table = raspberrypi_rtc_id,
+	.probe = rpi_rtc_probe
+};
+
+module_platform_driver(rpi_rtc_driver);
+
+MODULE_AUTHOR("Jonathan Bell <jonathan@raspberrypi.com>");
+MODULE_AUTHOR("Sander Speetjens <sander.speetjens@gmail.com>");
+MODULE_DESCRIPTION("Raspberry Pi RTC driver");
+MODULE_LICENSE("Dual BSD/GPL");
diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h
index 975bef529854..8c3d43977a03 100644
--- a/include/soc/bcm2835/raspberrypi-firmware.h
+++ b/include/soc/bcm2835/raspberrypi-firmware.h
@@ -75,6 +75,7 @@ enum rpi_firmware_property_tag {
 	RPI_FIRMWARE_GET_THROTTLED =                          0x00030046,
 	RPI_FIRMWARE_GET_CLOCK_MEASURED =                     0x00030047,
 	RPI_FIRMWARE_NOTIFY_REBOOT =                          0x00030048,
+	RPI_FIRMWARE_GET_RTC_REG =                            0x00030087,
 	RPI_FIRMWARE_SET_CLOCK_STATE =                        0x00038001,
 	RPI_FIRMWARE_SET_CLOCK_RATE =                         0x00038002,
 	RPI_FIRMWARE_SET_VOLTAGE =                            0x00038003,
@@ -92,6 +93,7 @@ enum rpi_firmware_property_tag {
 	RPI_FIRMWARE_SET_POE_HAT_VAL =                        0x00030050,
 	RPI_FIRMWARE_NOTIFY_XHCI_RESET =                      0x00030058,
 	RPI_FIRMWARE_NOTIFY_DISPLAY_DONE =                    0x00030066,
+	RPI_FIRMWARE_SET_RTC_REG =                            0x00038087,
 
 	/* Dispmanx TAGS */
 	RPI_FIRMWARE_FRAMEBUFFER_ALLOCATE =                   0x00040001,
-- 
2.56.0

Re: [PATCH v12 1/3] dt-bindings: rtc: Add missing type to trickle-voltage-millivolt

[sashiko-bot]

> The trickle-voltage-millivolt property had no associated type.
> -millivolt is not a default property unit suffix, so the schema does
> not automatically infer uint32. Explicitly reference the uint32
> definition so the type is correctly declared.
> 
> Suggested-by: Rob Herring <robh@kernel.org>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
> Signed-off-by: Sander Speetjens <sander.speetjens@gmail.com>

Sashiko has reviewed this patch and found no issues.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261018143712.1040152-1-sander.speetjens@gmail.com?part=1

Re: [PATCH v12 2/3] dt-bindings: rtc: Add property for Raspberry Pi 5 RTC

[sashiko-bot]

> The Raspberry Pi 5 has a built-in RTC that can be battery-backed
> via the VBAT pin. When a rechargeable coin cell is used, the
> hardware requires a trickle-charge voltage to keep the battery
> topped up.
> 
> Expose the trickle-voltage-millivolt DT property so the driver can
> program the correct charge voltage for board specific configurations with
> the attached battery.
> 
> The property is added to the existing raspberrypi,bcm2835-firmware
> binding (rather than creating a new RTC node) because the RTC is
> accessed exclusively through the firmware mailbox interface.
> We only $ref the individual property from rtc.yaml and do not
> reference the full schema, because the firmware node name does not
> match the $nodename pattern required by rtc.yaml.
> 
> Acked-by: Conor Dooley <conor.dooley@microchip.com>
> Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
> Signed-off-by: Sander Speetjens <sander.speetjens@gmail.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261018143712.1040152-1-sander.speetjens@gmail.com?part=2

Re: [PATCH v12 3/3] rtc: Add Raspberry Pi 5 RTC driver

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] rtc: Kconfig RTC_DRV_RPI depends on ARCH_BRCMSTB instead of ARCH_BCM2835
--

commit 764db262bbaebd42035bc0933220419e0e4cbc7d
Author: Sander Speetjens <sander.speetjens@gmail.com>

rtc: Add Raspberry Pi 5 RTC driver

This commit adds the Raspberry Pi 5 RTC driver, which accesses the custom
DA9091 RTC through the Raspberry Pi firmware mailbox, and registers the
raspberrypi-rtc platform device from drivers/firmware/raspberrypi.c on
brcm,bcm2712 machines.

> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index 05b9233b94189..6adaf425a76bc 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -1999,6 +1999,18 @@ config RTC_DRV_R7301
>  	   This driver can also be built as a module. If so, the module
>  	   will be called rtc-r7301.
>  
> +config RTC_DRV_RPI
> +	tristate "Raspberry Pi RTC"
> +	depends on RASPBERRYPI_FIRMWARE || (COMPILE_TEST && !RASPBERRYPI_FIRMWARE)
> +	depends on ARCH_BRCMSTB || COMPILE_TEST
> +	default ARCH_BRCMSTB

[Severity: Medium]
Should RTC_DRV_RPI depend on and default to ARCH_BCM2835 instead of
ARCH_BRCMSTB (or rely on the RASPBERRYPI_FIRMWARE dependency)?

In drivers/firmware/Kconfig, RASPBERRYPI_FIRMWARE is gated on ARCH_BCM2835:

config RASPBERRYPI_FIRMWARE
	tristate "Raspberry Pi Firmware Driver"
	depends on ARCH_BCM2835 || COMPILE_TEST
	depends on ARM || ARM64
	depends on MAILBOX
	default ARCH_BCM2835

When COMPILE_TEST=n, a configuration with ARCH_BCM2835=y,
RASPBERRYPI_FIRMWARE=y, and ARCH_BRCMSTB=n will register the
raspberrypi-rtc platform device in rpi_register_rtc_driver(), but
RTC_DRV_RPI cannot be enabled. Conversely, with ARCH_BRCMSTB=y and
ARCH_BCM2835=n, RASPBERRYPI_FIRMWARE cannot be enabled, so RTC_DRV_RPI's
first dependency is not satisfied.

> +	help
> +	  If you say yes here you get support for the RTC found on
> +	  Raspberry Pi 5th gen devices.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called rtc-raspberrypi.
> +
>  config RTC_DRV_STM32
>  	tristate "STM32 RTC"
>  	select REGMAP_MMIO

[ ... ]

> 
>

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Sashiko AI review · https://sashiko.dev/#/patchset/20261018143712.1040152-1-sander.speetjens@gmail.com?part=3