[PATCH v9 0/9] Turris Omnia MCU driver

[PATCH v9 0/9] Turris Omnia MCU driver

[Marek Behún]

Hello Andy, Hans, Ilpo, Arnd, Gregory, and others,

this is v9 of the series adding Turris Omnia MCU driver.

This series still depends on the immutable branch between LEDs and
locking, introducing devm_mutex_init(), see the PR
  https://lore.kernel.org/linux-leds/20240412084616.GR2399047@google.com/

See also cover letters for v1, v2, v3, v4, v5, v6, v7 and v8:
  https://patchwork.kernel.org/project/linux-soc/cover/20230823161012.6986-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20230919103815.16818-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20231023143130.11602-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20231026161803.16750-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20240323164359.21642-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20240418121116.22184-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20240424173809.7214-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20240430115111.3453-1-kabel@kernel.org/

Changes since v8:
- removed the MACH_ARMADA_38X || COMPILE_TEST dependency for the
  CZNIC_PLATFORMS Kconfig option in the Kconfig file, as suggested
  by Andy (patch 2)
- fixed the issues in the global header turris-omnia-mcu-interface.h
  pointed out by Andy and Ilpo: added the "OMNIA_" prefix to all
  enumerator entries, added trailing commas, converted to use
  FIELD_PREP_CONST() (patches 2-7)
- added comment why we can't use ether_addr_copy(), as requested by
  Andy (patch 2)
- rewritten the error message for when the MCU does not support
  reporting features, requested by Andy (patch 2)
- changed how the nul-byte is assigned to the end of bin2hex() result,
  requested by Andy (patch 2)
- made the omnia_cmd_write_read() function final in patch 2, instead of
  updating it in subsequent patches, requested by Andy
- in order to be more consistent, changed the omnia_cmd_read_u8() and
  omnia_cmd_read_u16() functions to return zero on success and the read
  value is passed into a pointer, and then added a new function
  omnia_cmd_read_u32(), as requested by Ilpo (he did not like the
  inconsistency in omnia_mcu_read_features(), where the
  omnia_cmd_read_u16() hid the le16_to_cpu() call, but then we did an
  explicit call to le32_to_cpu() when reading 32-bit features) (patch 2)
- some other minor tweaks (changed the version type from u8[] to char[],
  changed len type from size_t to unsigned int in omnia_cmd_write())
  (patches 2 & 3)
- dropped the "gpio%u." prefix from GPIO line names, Andy pointed out
  why this is wrong (patch 3)
- decoupled GPIOs information struct definition and assignment and put
  filling macros before the assignment, requested by Andy (patch 3)
- moved return value check into the guarded scope, suggested by Andy
  (patch 3)
- put some assignments into the definition lines, suggested by Andy
  (patch 3)
- fixed some typos (patches 2 & 3)
- refactored the reply length computation into a new function
  omnia_compute_reply_length(), as requested by Andy (patch 3)

Marek Behún (9):
  dt-bindings: firmware: add cznic,turris-omnia-mcu binding
  platform: cznic: Add preliminary support for Turris Omnia MCU
  platform: cznic: turris-omnia-mcu: Add support for MCU connected GPIOs
  platform: cznic: turris-omnia-mcu: Add support for poweroff and wakeup
  platform: cznic: turris-omnia-mcu: Add support for MCU watchdog
  platform: cznic: turris-omnia-mcu: Add support for MCU provided TRNG
  platform: cznic: turris-omnia-mcu: Add support for digital message
    signing via debugfs
  ARM: dts: turris-omnia: Add MCU system-controller node
  ARM: dts: turris-omnia: Add GPIO key node for front button

 .../ABI/testing/debugfs-turris-omnia-mcu      |   13 +
 .../sysfs-bus-i2c-devices-turris-omnia-mcu    |  126 ++
 .../firmware/cznic,turris-omnia-mcu.yaml      |   86 ++
 MAINTAINERS                                   |    5 +
 .../dts/marvell/armada-385-turris-omnia.dts   |   35 +-
 drivers/platform/Kconfig                      |    2 +
 drivers/platform/Makefile                     |    1 +
 drivers/platform/cznic/Kconfig                |   50 +
 drivers/platform/cznic/Makefile               |    9 +
 .../platform/cznic/turris-omnia-mcu-base.c    |  451 +++++++
 .../platform/cznic/turris-omnia-mcu-debugfs.c |  207 ++++
 .../platform/cznic/turris-omnia-mcu-gpio.c    | 1040 +++++++++++++++++
 .../cznic/turris-omnia-mcu-sys-off-wakeup.c   |  258 ++++
 .../platform/cznic/turris-omnia-mcu-trng.c    |  103 ++
 .../cznic/turris-omnia-mcu-watchdog.c         |  127 ++
 drivers/platform/cznic/turris-omnia-mcu.h     |  210 ++++
 include/linux/turris-omnia-mcu-interface.h    |  249 ++++
 17 files changed, 2971 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/ABI/testing/debugfs-turris-omnia-mcu
 create mode 100644 Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
 create mode 100644 Documentation/devicetree/bindings/firmware/cznic,turris-omnia-mcu.yaml
 create mode 100644 drivers/platform/cznic/Kconfig
 create mode 100644 drivers/platform/cznic/Makefile
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu-base.c
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu-debugfs.c
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu-gpio.c
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu-sys-off-wakeup.c
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu-trng.c
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu-watchdog.c
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu.h
 create mode 100644 include/linux/turris-omnia-mcu-interface.h

-- 
2.43.2

[PATCH v9 2/9] platform: cznic: Add preliminary support for Turris Omnia MCU

[Marek Behún]

Add the basic skeleton for a new platform driver for the microcontroller
found on the Turris Omnia board.

Signed-off-by: Marek Behún <kabel@kernel.org>
---
 .../sysfs-bus-i2c-devices-turris-omnia-mcu    |  81 ++++
 MAINTAINERS                                   |   3 +
 drivers/platform/Kconfig                      |   2 +
 drivers/platform/Makefile                     |   1 +
 drivers/platform/cznic/Kconfig                |  25 ++
 drivers/platform/cznic/Makefile               |   4 +
 .../platform/cznic/turris-omnia-mcu-base.c    | 394 ++++++++++++++++++
 drivers/platform/cznic/turris-omnia-mcu.h     |  70 ++++
 include/linux/turris-omnia-mcu-interface.h    | 249 +++++++++++
 9 files changed, 829 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
 create mode 100644 drivers/platform/cznic/Kconfig
 create mode 100644 drivers/platform/cznic/Makefile
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu-base.c
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu.h
 create mode 100644 include/linux/turris-omnia-mcu-interface.h

diff --git a/Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu b/Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
new file mode 100644
index 000000000000..8245c1f15c71
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
@@ -0,0 +1,81 @@
+What:		/sys/bus/i2c/devices/<mcu_device>/board_revision
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains board revision number.
+
+		Only available if board information is burned in the MCU (older
+		revisions have board information burned in the ATSHA204-A chip).
+
+		Format: %u.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/first_mac_address
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains device first MAC address. Each Turris Omnia is
+		allocated 3 MAC addresses. The two additional addresses are
+		computed from the first one by incrementing it.
+
+		Only available if board information is burned in the MCU (older
+		revisions have board information burned in the ATSHA204-A chip).
+
+		Format: %pM.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/fw_features
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Newer versions of the microcontroller firmware report the
+		features they support. These can be read from this file. If the
+		MCU firmware is too old, this file reads 0x0.
+
+		Format: 0x%x.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/fw_version_hash_application
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains the version hash (commit hash) of the application
+		part of the microcontroller firmware.
+
+		Format: %s.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/fw_version_hash_bootloader
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains the version hash (commit hash) of the bootloader
+		part of the microcontroller firmware.
+
+		Format: %s.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/mcu_type
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains the microcontroller type (STM32, GD32, MKL).
+
+		Format: %s.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/reset_selector
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains the selected factory reset level, determined by
+		how long the rear reset button was held by the user during board
+		reset.
+
+		Format: %i.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/serial_number
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains the 64-bit board serial number in hexadecimal
+		format.
+
+		Only available if board information is burned in the MCU (older
+		revisions have board information burned in the ATSHA204-A chip).
+
+		Format: %016X.
diff --git a/MAINTAINERS b/MAINTAINERS
index aba40663f3f8..b27cc5feb64f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2139,6 +2139,7 @@ M:	Marek Behún <kabel@kernel.org>
 S:	Maintained
 W:	https://www.turris.cz/
 F:	Documentation/ABI/testing/debugfs-moxtet
+F:	Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
 F:	Documentation/ABI/testing/sysfs-bus-moxtet-devices
 F:	Documentation/ABI/testing/sysfs-firmware-turris-mox-rwtm
 F:	Documentation/devicetree/bindings/bus/moxtet.txt
@@ -2152,10 +2153,12 @@ F:	drivers/firmware/turris-mox-rwtm.c
 F:	drivers/gpio/gpio-moxtet.c
 F:	drivers/leds/leds-turris-omnia.c
 F:	drivers/mailbox/armada-37xx-rwtm-mailbox.c
+F:	drivers/platform/cznic/
 F:	drivers/watchdog/armada_37xx_wdt.c
 F:	include/dt-bindings/bus/moxtet.h
 F:	include/linux/armada-37xx-rwtm-mailbox.h
 F:	include/linux/moxtet.h
+F:	include/linux/turris-omnia-mcu-interface.h
 
 ARM/FARADAY FA526 PORT
 M:	Hans Ulli Kroll <ulli.kroll@googlemail.com>
diff --git a/drivers/platform/Kconfig b/drivers/platform/Kconfig
index 868b20361769..fef907a94001 100644
--- a/drivers/platform/Kconfig
+++ b/drivers/platform/Kconfig
@@ -7,6 +7,8 @@ source "drivers/platform/goldfish/Kconfig"
 
 source "drivers/platform/chrome/Kconfig"
 
+source "drivers/platform/cznic/Kconfig"
+
 source "drivers/platform/mellanox/Kconfig"
 
 source "drivers/platform/olpc/Kconfig"
diff --git a/drivers/platform/Makefile b/drivers/platform/Makefile
index 41640172975a..8bf189264374 100644
--- a/drivers/platform/Makefile
+++ b/drivers/platform/Makefile
@@ -10,4 +10,5 @@ obj-$(CONFIG_MIPS)		+= mips/
 obj-$(CONFIG_OLPC_EC)		+= olpc/
 obj-$(CONFIG_GOLDFISH)		+= goldfish/
 obj-$(CONFIG_CHROME_PLATFORMS)	+= chrome/
+obj-$(CONFIG_CZNIC_PLATFORMS)	+= cznic/
 obj-$(CONFIG_SURFACE_PLATFORMS)	+= surface/
diff --git a/drivers/platform/cznic/Kconfig b/drivers/platform/cznic/Kconfig
new file mode 100644
index 000000000000..db5f4a673d28
--- /dev/null
+++ b/drivers/platform/cznic/Kconfig
@@ -0,0 +1,25 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# For a description of the syntax of this configuration file,
+# see Documentation/kbuild/kconfig-language.rst.
+#
+
+menuconfig CZNIC_PLATFORMS
+	bool "Platform support for CZ.NIC's Turris hardware"
+	help
+	  Say Y here to be able to choose driver support for CZ.NIC's Turris
+	  devices. This option alone does not add any kernel code.
+
+if CZNIC_PLATFORMS
+
+config TURRIS_OMNIA_MCU
+	tristate "Turris Omnia MCU driver"
+	depends on MACH_ARMADA_38X || COMPILE_TEST
+	depends on I2C
+	help
+	  Say Y here to add support for the features implemented by the
+	  microcontroller on the CZ.NIC's Turris Omnia SOHO router.
+	  To compile this driver as a module, choose M here; the module will be
+	  called turris-omnia-mcu.
+
+endif # CZNIC_PLATFORMS
diff --git a/drivers/platform/cznic/Makefile b/drivers/platform/cznic/Makefile
new file mode 100644
index 000000000000..31adca73bb94
--- /dev/null
+++ b/drivers/platform/cznic/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_TURRIS_OMNIA_MCU)	+= turris-omnia-mcu.o
+turris-omnia-mcu-y		:= turris-omnia-mcu-base.o
diff --git a/drivers/platform/cznic/turris-omnia-mcu-base.c b/drivers/platform/cznic/turris-omnia-mcu-base.c
new file mode 100644
index 000000000000..9b5acb857e07
--- /dev/null
+++ b/drivers/platform/cznic/turris-omnia-mcu-base.c
@@ -0,0 +1,394 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CZ.NIC's Turris Omnia MCU driver
+ *
+ * 2024 by Marek Behún <kabel@kernel.org>
+ */
+
+#include <linux/array_size.h>
+#include <linux/bits.h>
+#include <linux/device.h>
+#include <linux/hex.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/turris-omnia-mcu-interface.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+
+#include "turris-omnia-mcu.h"
+
+#define OMNIA_FW_VERSION_LEN		20
+#define OMNIA_FW_VERSION_HEX_LEN	(2 * OMNIA_FW_VERSION_LEN + 1)
+#define OMNIA_BOARD_INFO_LEN		16
+
+int omnia_cmd_write_read(const struct i2c_client *client,
+			 void *cmd, unsigned int cmd_len,
+			 void *reply, unsigned int reply_len)
+{
+	struct i2c_msg msgs[2];
+	int ret, num;
+
+	msgs[0].addr = client->addr;
+	msgs[0].flags = 0;
+	msgs[0].len = cmd_len;
+	msgs[0].buf = cmd;
+	num = 1;
+
+	if (reply_len) {
+		msgs[1].addr = client->addr;
+		msgs[1].flags = I2C_M_RD;
+		msgs[1].len = reply_len;
+		msgs[1].buf = reply;
+		num++;
+	}
+
+	ret = i2c_transfer(client->adapter, msgs, num);
+	if (ret < 0)
+		return ret;
+	if (ret != num)
+		return -EIO;
+
+	return 0;
+}
+
+static int omnia_get_version_hash(struct omnia_mcu *mcu, bool bootloader,
+				  char version[static OMNIA_FW_VERSION_HEX_LEN])
+{
+	u8 reply[OMNIA_FW_VERSION_LEN];
+	char *p;
+	int err;
+
+	err = omnia_cmd_read(mcu->client,
+			     bootloader ? OMNIA_CMD_GET_FW_VERSION_BOOT
+					: OMNIA_CMD_GET_FW_VERSION_APP,
+			     reply, sizeof(reply));
+	if (err)
+		return err;
+
+	p = bin2hex(version, reply, OMNIA_FW_VERSION_LEN);
+	*p = '\0';
+
+	return 0;
+}
+
+static ssize_t fw_version_hash_show(struct device *dev, char *buf,
+				    bool bootloader)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+	char version[OMNIA_FW_VERSION_HEX_LEN];
+	int err;
+
+	err = omnia_get_version_hash(mcu, bootloader, version);
+	if (err)
+		return err;
+
+	return sysfs_emit(buf, "%s\n", version);
+}
+
+static ssize_t fw_version_hash_application_show(struct device *dev,
+						struct device_attribute *a,
+						char *buf)
+{
+	return fw_version_hash_show(dev, buf, false);
+}
+static DEVICE_ATTR_RO(fw_version_hash_application);
+
+static ssize_t fw_version_hash_bootloader_show(struct device *dev,
+					       struct device_attribute *a,
+					       char *buf)
+{
+	return fw_version_hash_show(dev, buf, true);
+}
+static DEVICE_ATTR_RO(fw_version_hash_bootloader);
+
+static ssize_t fw_features_show(struct device *dev, struct device_attribute *a,
+				char *buf)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "0x%x\n", mcu->features);
+}
+static DEVICE_ATTR_RO(fw_features);
+
+static ssize_t mcu_type_show(struct device *dev, struct device_attribute *a,
+			     char *buf)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%s\n", mcu->type);
+}
+static DEVICE_ATTR_RO(mcu_type);
+
+static ssize_t reset_selector_show(struct device *dev,
+				   struct device_attribute *a, char *buf)
+{
+	u8 reply;
+	int err;
+
+	err = omnia_cmd_read_u8(to_i2c_client(dev), OMNIA_CMD_GET_RESET,
+				&reply);
+	if (err)
+		return err;
+
+	return sysfs_emit(buf, "%d\n", reply);
+}
+static DEVICE_ATTR_RO(reset_selector);
+
+static ssize_t serial_number_show(struct device *dev,
+				  struct device_attribute *a, char *buf)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%016llX\n", mcu->board_serial_number);
+}
+static DEVICE_ATTR_RO(serial_number);
+
+static ssize_t first_mac_address_show(struct device *dev,
+				      struct device_attribute *a, char *buf)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%pM\n", mcu->board_first_mac);
+}
+static DEVICE_ATTR_RO(first_mac_address);
+
+static ssize_t board_revision_show(struct device *dev,
+				   struct device_attribute *a, char *buf)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%u\n", mcu->board_revision);
+}
+static DEVICE_ATTR_RO(board_revision);
+
+static struct attribute *omnia_mcu_base_attrs[] = {
+	&dev_attr_fw_version_hash_application.attr,
+	&dev_attr_fw_version_hash_bootloader.attr,
+	&dev_attr_fw_features.attr,
+	&dev_attr_mcu_type.attr,
+	&dev_attr_reset_selector.attr,
+	&dev_attr_serial_number.attr,
+	&dev_attr_first_mac_address.attr,
+	&dev_attr_board_revision.attr,
+	NULL
+};
+
+static umode_t omnia_mcu_base_attrs_visible(struct kobject *kobj,
+					    struct attribute *a, int n)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+
+	if ((a == &dev_attr_serial_number.attr ||
+	     a == &dev_attr_first_mac_address.attr ||
+	     a == &dev_attr_board_revision.attr) &&
+	    !(mcu->features & OMNIA_FEAT_BOARD_INFO))
+		return 0;
+
+	return a->mode;
+}
+
+static const struct attribute_group omnia_mcu_base_group = {
+	.attrs = omnia_mcu_base_attrs,
+	.is_visible = omnia_mcu_base_attrs_visible,
+};
+
+static const struct attribute_group *omnia_mcu_groups[] = {
+	&omnia_mcu_base_group,
+	NULL
+};
+
+static void omnia_mcu_print_version_hash(struct omnia_mcu *mcu, bool bootloader)
+{
+	const char *type = bootloader ? "bootloader" : "application";
+	struct device *dev = &mcu->client->dev;
+	char version[OMNIA_FW_VERSION_HEX_LEN];
+	int err;
+
+	err = omnia_get_version_hash(mcu, bootloader, version);
+	if (err) {
+		dev_err(dev, "Cannot read MCU %s firmware version: %d\n",
+			type, err);
+		return;
+	}
+
+	dev_info(dev, "MCU %s firmware version hash: %s\n", type, version);
+}
+
+static const char *omnia_status_to_mcu_type(u16 status)
+{
+	switch (status & OMNIA_STS_MCU_TYPE_MASK) {
+	case OMNIA_STS_MCU_TYPE_STM32:
+		return "STM32";
+	case OMNIA_STS_MCU_TYPE_GD32:
+		return "GD32";
+	case OMNIA_STS_MCU_TYPE_MKL:
+		return "MKL";
+	default:
+		return "unknown";
+	}
+}
+
+static void omnia_info_missing_feature(struct device *dev, const char *feature)
+{
+	dev_info(dev,
+		 "Your board's MCU firmware does not support the %s feature.\n",
+		 feature);
+}
+
+static int omnia_mcu_read_features(struct omnia_mcu *mcu)
+{
+	static const struct {
+		u16 mask;
+		const char *name;
+	} features[] = {
+#define _DEF_FEAT(_n, _m) { OMNIA_FEAT_ ## _n, _m }
+		_DEF_FEAT(EXT_CMDS,		"extended control and status"),
+		_DEF_FEAT(WDT_PING,		"watchdog pinging"),
+		_DEF_FEAT(LED_STATE_EXT_MASK,	"peripheral LED pins reading"),
+		_DEF_FEAT(NEW_INT_API,		"new interrupt API"),
+		_DEF_FEAT(POWEROFF_WAKEUP,	"poweroff and wakeup"),
+		_DEF_FEAT(TRNG,			"true random number generator"),
+#undef _DEF_FEAT
+	};
+	struct device *dev = &mcu->client->dev;
+	bool suggest_fw_upgrade = false;
+	u16 status;
+	int err;
+
+	/* status word holds MCU type, which we need below */
+	err = omnia_cmd_read_u16(mcu->client, OMNIA_CMD_GET_STATUS_WORD,
+				 &status);
+	if (err)
+		return err;
+
+	/*
+	 * check whether MCU firmware supports the OMNIA_CMD_GET_FEATURES
+	 * command
+	 */
+	if (status & OMNIA_STS_FEATURES_SUPPORTED) {
+		/* try read 32-bit features */
+		err = omnia_cmd_read_u32(mcu->client, OMNIA_CMD_GET_FEATURES,
+					 &mcu->features);
+		if (err) {
+			/* try read 16-bit features */
+			u16 features16;
+
+			err = omnia_cmd_read_u16(mcu->client,
+						 OMNIA_CMD_GET_FEATURES,
+						 &features16);
+			if (err)
+				return err;
+
+			mcu->features = features16;
+		} else {
+			if (mcu->features & OMNIA_FEAT_FROM_BIT_16_INVALID)
+				mcu->features &= GENMASK(15, 0);
+		}
+	} else {
+		dev_info(dev,
+			 "Your board's MCU firmware does not support feature reading.\n");
+		suggest_fw_upgrade = true;
+	}
+
+	mcu->type = omnia_status_to_mcu_type(status);
+	dev_info(dev, "MCU type %s%s\n", mcu->type,
+		 (mcu->features & OMNIA_FEAT_PERIPH_MCU) ?
+			", with peripheral resets wired" : "");
+
+	omnia_mcu_print_version_hash(mcu, true);
+
+	if (mcu->features & OMNIA_FEAT_BOOTLOADER)
+		dev_warn(dev,
+			 "MCU is running bootloader firmware. Was firmware upgrade interrupted?\n");
+	else
+		omnia_mcu_print_version_hash(mcu, false);
+
+	for (unsigned int i = 0; i < ARRAY_SIZE(features); i++) {
+		if (mcu->features & features[i].mask)
+			continue;
+
+		omnia_info_missing_feature(dev, features[i].name);
+		suggest_fw_upgrade = true;
+	}
+
+	if (suggest_fw_upgrade)
+		dev_info(dev,
+			 "Consider upgrading MCU firmware with the omnia-mcutool utility.\n");
+
+	return 0;
+}
+
+static int omnia_mcu_read_board_info(struct omnia_mcu *mcu)
+{
+	u8 reply[1 + OMNIA_BOARD_INFO_LEN];
+	int err;
+
+	err = omnia_cmd_read(mcu->client, OMNIA_CMD_BOARD_INFO_GET, reply,
+			     sizeof(reply));
+	if (err)
+		return err;
+
+	if (reply[0] != OMNIA_BOARD_INFO_LEN)
+		return -EIO;
+
+	mcu->board_serial_number = get_unaligned_le64(&reply[1]);
+
+	/* we can't use ether_addr_copy() because reply is not u16-aligned */
+	memcpy(mcu->board_first_mac, &reply[9], ETH_ALEN);
+
+	mcu->board_revision = reply[15];
+
+	return 0;
+}
+
+static int omnia_mcu_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct omnia_mcu *mcu;
+	int err;
+
+	if (!client->irq)
+		return dev_err_probe(dev, -EINVAL, "IRQ resource not found\n");
+
+	mcu = devm_kzalloc(dev, sizeof(*mcu), GFP_KERNEL);
+	if (!mcu)
+		return -ENOMEM;
+
+	mcu->client = client;
+	i2c_set_clientdata(client, mcu);
+
+	err = omnia_mcu_read_features(mcu);
+	if (err)
+		return dev_err_probe(dev, err,
+				     "Cannot determine MCU supported features\n");
+
+	if (mcu->features & OMNIA_FEAT_BOARD_INFO) {
+		err = omnia_mcu_read_board_info(mcu);
+		if (err)
+			return dev_err_probe(dev, err,
+					     "Cannot read board info\n");
+	}
+
+	return 0;
+}
+
+static const struct of_device_id of_omnia_mcu_match[] = {
+	{ .compatible = "cznic,turris-omnia-mcu" },
+	{}
+};
+
+static struct i2c_driver omnia_mcu_driver = {
+	.probe		= omnia_mcu_probe,
+	.driver		= {
+		.name	= "turris-omnia-mcu",
+		.of_match_table = of_omnia_mcu_match,
+		.dev_groups = omnia_mcu_groups,
+	},
+};
+module_i2c_driver(omnia_mcu_driver);
+
+MODULE_AUTHOR("Marek Behun <kabel@kernel.org>");
+MODULE_DESCRIPTION("CZ.NIC's Turris Omnia MCU");
+MODULE_LICENSE("GPL");
diff --git a/drivers/platform/cznic/turris-omnia-mcu.h b/drivers/platform/cznic/turris-omnia-mcu.h
new file mode 100644
index 000000000000..d511321ee485
--- /dev/null
+++ b/drivers/platform/cznic/turris-omnia-mcu.h
@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * CZ.NIC's Turris Omnia MCU driver
+ *
+ * 2024 by Marek Behún <kabel@kernel.org>
+ */
+
+#ifndef __TURRIS_OMNIA_MCU_H
+#define __TURRIS_OMNIA_MCU_H
+
+#include <linux/if_ether.h>
+#include <linux/types.h>
+#include <asm/byteorder.h>
+
+struct i2c_client;
+
+struct omnia_mcu {
+	struct i2c_client *client;
+	const char *type;
+	u32 features;
+
+	/* board information */
+	u64 board_serial_number;
+	u8 board_first_mac[ETH_ALEN];
+	u8 board_revision;
+};
+
+int omnia_cmd_write_read(const struct i2c_client *client,
+			 void *cmd, unsigned int cmd_len,
+			 void *reply, unsigned int reply_len);
+
+static inline int omnia_cmd_read(const struct i2c_client *client, u8 cmd,
+				 void *reply, unsigned int len)
+{
+	return omnia_cmd_write_read(client, &cmd, 1, reply, len);
+}
+
+static inline int omnia_cmd_read_u32(const struct i2c_client *client, u8 cmd,
+				     u32 *dst)
+{
+	__le32 reply;
+	int err;
+
+	err = omnia_cmd_read(client, cmd, &reply, sizeof(reply));
+	if (!err)
+		*dst = le32_to_cpu(reply);
+
+	return err;
+}
+
+static inline int omnia_cmd_read_u16(const struct i2c_client *client, u8 cmd,
+				     u16 *dst)
+{
+	__le16 reply;
+	int err;
+
+	err = omnia_cmd_read(client, cmd, &reply, sizeof(reply));
+	if (!err)
+		*dst = le16_to_cpu(reply);
+
+	return err;
+}
+
+static inline int omnia_cmd_read_u8(const struct i2c_client *client, u8 cmd,
+				    u8 *reply)
+{
+	return omnia_cmd_read(client, cmd, reply, sizeof(*reply));
+}
+
+#endif /* __TURRIS_OMNIA_MCU_H */
diff --git a/include/linux/turris-omnia-mcu-interface.h b/include/linux/turris-omnia-mcu-interface.h
new file mode 100644
index 000000000000..2da8cbeb158a
--- /dev/null
+++ b/include/linux/turris-omnia-mcu-interface.h
@@ -0,0 +1,249 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * CZ.NIC's Turris Omnia MCU I2C interface commands definitions
+ *
+ * 2024 by Marek Behún <kabel@kernel.org>
+ */
+
+#ifndef __TURRIS_OMNIA_MCU_INTERFACE_H
+#define __TURRIS_OMNIA_MCU_INTERFACE_H
+
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+
+enum omnia_commands_e {
+	OMNIA_CMD_GET_STATUS_WORD		= 0x01, /* slave sends status word back */
+	OMNIA_CMD_GENERAL_CONTROL		= 0x02,
+	OMNIA_CMD_LED_MODE			= 0x03, /* default/user */
+	OMNIA_CMD_LED_STATE			= 0x04, /* LED on/off */
+	OMNIA_CMD_LED_COLOR			= 0x05, /* LED number + RED + GREEN + BLUE */
+	OMNIA_CMD_USER_VOLTAGE			= 0x06,
+	OMNIA_CMD_SET_BRIGHTNESS		= 0x07,
+	OMNIA_CMD_GET_BRIGHTNESS		= 0x08,
+	OMNIA_CMD_GET_RESET			= 0x09,
+	OMNIA_CMD_GET_FW_VERSION_APP		= 0x0A, /* 20B git hash number */
+	OMNIA_CMD_SET_WATCHDOG_STATE		= 0x0B, /* 0 - disable
+							 * 1 - enable / ping
+							 * after boot watchdog is started
+							 * with 2 minutes timeout
+							 */
+
+	/* OMNIA_CMD_WATCHDOG_STATUS		= 0x0C, not implemented anymore */
+
+	OMNIA_CMD_GET_WATCHDOG_STATE		= 0x0D,
+	OMNIA_CMD_GET_FW_VERSION_BOOT		= 0x0E, /* 20B Git hash number */
+	OMNIA_CMD_GET_FW_CHECKSUM		= 0x0F, /* 4B length, 4B checksum */
+
+	/* available if FEATURES_SUPPORTED bit set in status word */
+	OMNIA_CMD_GET_FEATURES			= 0x10,
+
+	/* available if EXT_CMD bit set in features */
+	OMNIA_CMD_GET_EXT_STATUS_DWORD		= 0x11,
+	OMNIA_CMD_EXT_CONTROL			= 0x12,
+	OMNIA_CMD_GET_EXT_CONTROL_STATUS	= 0x13,
+
+	/* available if NEW_INT_API bit set in features */
+	OMNIA_CMD_GET_INT_AND_CLEAR		= 0x14,
+	OMNIA_CMD_GET_INT_MASK			= 0x15,
+	OMNIA_CMD_SET_INT_MASK			= 0x16,
+
+	/* available if FLASHING bit set in features */
+	OMNIA_CMD_FLASH				= 0x19,
+
+	/* available if WDT_PING bit set in features */
+	OMNIA_CMD_SET_WDT_TIMEOUT		= 0x20,
+	OMNIA_CMD_GET_WDT_TIMELEFT		= 0x21,
+
+	/* available if POWEROFF_WAKEUP bit set in features */
+	OMNIA_CMD_SET_WAKEUP			= 0x22,
+	OMNIA_CMD_GET_UPTIME_AND_WAKEUP		= 0x23,
+	OMNIA_CMD_POWER_OFF			= 0x24,
+
+	/* available if USB_OVC_PROT_SETTING bit set in features */
+	OMNIA_CMD_SET_USB_OVC_PROT		= 0x25,
+	OMNIA_CMD_GET_USB_OVC_PROT		= 0x26,
+
+	/* available if TRNG bit set in features */
+	OMNIA_CMD_TRNG_COLLECT_ENTROPY		= 0x28,
+
+	/* available if CRYPTO bit set in features */
+	OMNIA_CMD_CRYPTO_GET_PUBLIC_KEY		= 0x29,
+	OMNIA_CMD_CRYPTO_SIGN_MESSAGE		= 0x2A,
+	OMNIA_CMD_CRYPTO_COLLECT_SIGNATURE	= 0x2B,
+
+	/* available if BOARD_INFO it set in features */
+	OMNIA_CMD_BOARD_INFO_GET		= 0x2C,
+	OMNIA_CMD_BOARD_INFO_BURN		= 0x2D,
+
+	/* available only at address 0x2b (LED-controller) */
+	/* available only if LED_GAMMA_CORRECTION bit set in features */
+	OMNIA_CMD_SET_GAMMA_CORRECTION		= 0x30,
+	OMNIA_CMD_GET_GAMMA_CORRECTION		= 0x31,
+
+	/* available only at address 0x2b (LED-controller) */
+	/* available only if PER_LED_CORRECTION bit set in features */
+	/* available only if FROM_BIT_16_INVALID bit NOT set in features */
+	OMNIA_CMD_SET_LED_CORRECTIONS		= 0x32,
+	OMNIA_CMD_GET_LED_CORRECTIONS		= 0x33,
+};
+
+enum omnia_flashing_commands_e {
+	OMNIA_FLASH_CMD_UNLOCK		= 0x01,
+	OMNIA_FLASH_CMD_SIZE_AND_CSUM	= 0x02,
+	OMNIA_FLASH_CMD_PROGRAM		= 0x03,
+	OMNIA_FLASH_CMD_RESET		= 0x04,
+};
+
+enum omnia_sts_word_e {
+	OMNIA_STS_MCU_TYPE_MASK			= GENMASK(1, 0),
+	OMNIA_STS_MCU_TYPE_STM32		= FIELD_PREP_CONST(OMNIA_STS_MCU_TYPE_MASK, 0),
+	OMNIA_STS_MCU_TYPE_GD32			= FIELD_PREP_CONST(OMNIA_STS_MCU_TYPE_MASK, 1),
+	OMNIA_STS_MCU_TYPE_MKL			= FIELD_PREP_CONST(OMNIA_STS_MCU_TYPE_MASK, 2),
+	OMNIA_STS_FEATURES_SUPPORTED		= BIT(2),
+	OMNIA_STS_USER_REGULATOR_NOT_SUPPORTED	= BIT(3),
+	OMNIA_STS_CARD_DET			= BIT(4),
+	OMNIA_STS_MSATA_IND			= BIT(5),
+	OMNIA_STS_USB30_OVC			= BIT(6),
+	OMNIA_STS_USB31_OVC			= BIT(7),
+	OMNIA_STS_USB30_PWRON			= BIT(8),
+	OMNIA_STS_USB31_PWRON			= BIT(9),
+	OMNIA_STS_ENABLE_4V5			= BIT(10),
+	OMNIA_STS_BUTTON_MODE			= BIT(11),
+	OMNIA_STS_BUTTON_PRESSED		= BIT(12),
+	OMNIA_STS_BUTTON_COUNTER_MASK		= GENMASK(15, 13),
+};
+
+enum omnia_ctl_byte_e {
+	OMNIA_CTL_LIGHT_RST	= BIT(0),
+	OMNIA_CTL_HARD_RST	= BIT(1),
+	/* BIT(2) is currently reserved */
+	OMNIA_CTL_USB30_PWRON	= BIT(3),
+	OMNIA_CTL_USB31_PWRON	= BIT(4),
+	OMNIA_CTL_ENABLE_4V5	= BIT(5),
+	OMNIA_CTL_BUTTON_MODE	= BIT(6),
+	OMNIA_CTL_BOOTLOADER	= BIT(7),
+};
+
+enum omnia_features_e {
+	OMNIA_FEAT_PERIPH_MCU		= BIT(0),
+	OMNIA_FEAT_EXT_CMDS		= BIT(1),
+	OMNIA_FEAT_WDT_PING		= BIT(2),
+	OMNIA_FEAT_LED_STATE_EXT_MASK	= GENMASK(4, 3),
+	OMNIA_FEAT_LED_STATE_EXT	= FIELD_PREP_CONST(OMNIA_FEAT_LED_STATE_EXT_MASK, 1),
+	OMNIA_FEAT_LED_STATE_EXT_V32	= FIELD_PREP_CONST(OMNIA_FEAT_LED_STATE_EXT_MASK, 2),
+	OMNIA_FEAT_LED_GAMMA_CORRECTION	= BIT(5),
+	OMNIA_FEAT_NEW_INT_API		= BIT(6),
+	OMNIA_FEAT_BOOTLOADER		= BIT(7),
+	OMNIA_FEAT_FLASHING		= BIT(8),
+	OMNIA_FEAT_NEW_MESSAGE_API	= BIT(9),
+	OMNIA_FEAT_BRIGHTNESS_INT	= BIT(10),
+	OMNIA_FEAT_POWEROFF_WAKEUP	= BIT(11),
+	OMNIA_FEAT_CAN_OLD_MESSAGE_API	= BIT(12),
+	OMNIA_FEAT_TRNG			= BIT(13),
+	OMNIA_FEAT_CRYPTO		= BIT(14),
+	OMNIA_FEAT_BOARD_INFO		= BIT(15),
+
+	/*
+	 * Orginally the features command replied only 16 bits. If more were
+	 * read, either the I2C transaction failed or 0xff bytes were sent.
+	 * Therefore to consider bits 16 - 31 valid, one bit (20) was reserved
+	 * to be zero.
+	 */
+
+	/* Bits 16 - 19 correspond to bits 0 - 3 of status word */
+	OMNIA_FEAT_MCU_TYPE_MASK		= GENMASK(17, 16),
+	OMNIA_FEAT_MCU_TYPE_STM32		= FIELD_PREP_CONST(OMNIA_FEAT_MCU_TYPE_MASK, 0),
+	OMNIA_FEAT_MCU_TYPE_GD32		= FIELD_PREP_CONST(OMNIA_FEAT_MCU_TYPE_MASK, 1),
+	OMNIA_FEAT_MCU_TYPE_MKL			= FIELD_PREP_CONST(OMNIA_FEAT_MCU_TYPE_MASK, 2),
+	OMNIA_FEAT_FEATURES_SUPPORTED		= BIT(18),
+	OMNIA_FEAT_USER_REGULATOR_NOT_SUPPORTED	= BIT(19),
+
+	/* must not be set */
+	OMNIA_FEAT_FROM_BIT_16_INVALID	= BIT(20),
+
+	OMNIA_FEAT_PER_LED_CORRECTION	= BIT(21),
+	OMNIA_FEAT_USB_OVC_PROT_SETTING	= BIT(22),
+};
+
+enum omnia_ext_sts_dword_e {
+	OMNIA_EXT_STS_SFP_nDET		= BIT(0),
+	OMNIA_EXT_STS_LED_STATES_MASK	= GENMASK(31, 12),
+	OMNIA_EXT_STS_WLAN0_MSATA_LED	= BIT(12),
+	OMNIA_EXT_STS_WLAN1_LED		= BIT(13),
+	OMNIA_EXT_STS_WLAN2_LED		= BIT(14),
+	OMNIA_EXT_STS_WPAN0_LED		= BIT(15),
+	OMNIA_EXT_STS_WPAN1_LED		= BIT(16),
+	OMNIA_EXT_STS_WPAN2_LED		= BIT(17),
+	OMNIA_EXT_STS_WAN_LED0		= BIT(18),
+	OMNIA_EXT_STS_WAN_LED1		= BIT(19),
+	OMNIA_EXT_STS_LAN0_LED0		= BIT(20),
+	OMNIA_EXT_STS_LAN0_LED1		= BIT(21),
+	OMNIA_EXT_STS_LAN1_LED0		= BIT(22),
+	OMNIA_EXT_STS_LAN1_LED1		= BIT(23),
+	OMNIA_EXT_STS_LAN2_LED0		= BIT(24),
+	OMNIA_EXT_STS_LAN2_LED1		= BIT(25),
+	OMNIA_EXT_STS_LAN3_LED0		= BIT(26),
+	OMNIA_EXT_STS_LAN3_LED1		= BIT(27),
+	OMNIA_EXT_STS_LAN4_LED0		= BIT(28),
+	OMNIA_EXT_STS_LAN4_LED1		= BIT(29),
+	OMNIA_EXT_STS_LAN5_LED0		= BIT(30),
+	OMNIA_EXT_STS_LAN5_LED1		= BIT(31),
+};
+
+enum omnia_ext_ctl_e {
+	OMNIA_EXT_CTL_nRES_MMC		= BIT(0),
+	OMNIA_EXT_CTL_nRES_LAN		= BIT(1),
+	OMNIA_EXT_CTL_nRES_PHY		= BIT(2),
+	OMNIA_EXT_CTL_nPERST0		= BIT(3),
+	OMNIA_EXT_CTL_nPERST1		= BIT(4),
+	OMNIA_EXT_CTL_nPERST2		= BIT(5),
+	OMNIA_EXT_CTL_PHY_SFP		= BIT(6),
+	OMNIA_EXT_CTL_PHY_SFP_AUTO	= BIT(7),
+	OMNIA_EXT_CTL_nVHV_CTRL		= BIT(8),
+};
+
+enum omnia_int_e {
+	OMNIA_INT_CARD_DET		= BIT(0),
+	OMNIA_INT_MSATA_IND		= BIT(1),
+	OMNIA_INT_USB30_OVC		= BIT(2),
+	OMNIA_INT_USB31_OVC		= BIT(3),
+	OMNIA_INT_BUTTON_PRESSED	= BIT(4),
+	OMNIA_INT_SFP_nDET		= BIT(5),
+	OMNIA_INT_BRIGHTNESS_CHANGED	= BIT(6),
+	OMNIA_INT_TRNG			= BIT(7),
+	OMNIA_INT_MESSAGE_SIGNED	= BIT(8),
+
+	OMNIA_INT_LED_STATES_MASK	= GENMASK(31, 12),
+	OMNIA_INT_WLAN0_MSATA_LED	= BIT(12),
+	OMNIA_INT_WLAN1_LED		= BIT(13),
+	OMNIA_INT_WLAN2_LED		= BIT(14),
+	OMNIA_INT_WPAN0_LED		= BIT(15),
+	OMNIA_INT_WPAN1_LED		= BIT(16),
+	OMNIA_INT_WPAN2_LED		= BIT(17),
+	OMNIA_INT_WAN_LED0		= BIT(18),
+	OMNIA_INT_WAN_LED1		= BIT(19),
+	OMNIA_INT_LAN0_LED0		= BIT(20),
+	OMNIA_INT_LAN0_LED1		= BIT(21),
+	OMNIA_INT_LAN1_LED0		= BIT(22),
+	OMNIA_INT_LAN1_LED1		= BIT(23),
+	OMNIA_INT_LAN2_LED0		= BIT(24),
+	OMNIA_INT_LAN2_LED1		= BIT(25),
+	OMNIA_INT_LAN3_LED0		= BIT(26),
+	OMNIA_INT_LAN3_LED1		= BIT(27),
+	OMNIA_INT_LAN4_LED0		= BIT(28),
+	OMNIA_INT_LAN4_LED1		= BIT(29),
+	OMNIA_INT_LAN5_LED0		= BIT(30),
+	OMNIA_INT_LAN5_LED1		= BIT(31),
+};
+
+enum omnia_cmd_poweroff_e {
+	OMNIA_CMD_POWER_OFF_POWERON_BUTTON	= BIT(0),
+	OMNIA_CMD_POWER_OFF_MAGIC		= 0xdead,
+};
+
+enum omnia_cmd_usb_ovc_prot_e {
+	OMNIA_CMD_xET_USB_OVC_PROT_PORT_MASK	= GENMASK(3, 0),
+	OMNIA_CMD_xET_USB_OVC_PROT_ENABLE	= BIT(4),
+};
+
+#endif /* __TURRIS_OMNIA_MCU_INTERFACE_H */
-- 
2.43.2

[PATCH v9 5/9] platform: cznic: turris-omnia-mcu: Add support for MCU watchdog

[Marek Behún]

Add support for the watchdog mechanism provided by the MCU.

Signed-off-by: Marek Behún <kabel@kernel.org>
---
 drivers/platform/cznic/Kconfig                |   2 +
 drivers/platform/cznic/Makefile               |   1 +
 .../platform/cznic/turris-omnia-mcu-base.c    |   4 +
 .../cznic/turris-omnia-mcu-watchdog.c         | 127 ++++++++++++++++++
 drivers/platform/cznic/turris-omnia-mcu.h     |  24 ++++
 5 files changed, 158 insertions(+)
 create mode 100644 drivers/platform/cznic/turris-omnia-mcu-watchdog.c

diff --git a/drivers/platform/cznic/Kconfig b/drivers/platform/cznic/Kconfig
index c1e719235517..e262930b3faf 100644
--- a/drivers/platform/cznic/Kconfig
+++ b/drivers/platform/cznic/Kconfig
@@ -19,6 +19,7 @@ config TURRIS_OMNIA_MCU
 	select GPIOLIB
 	select GPIOLIB_IRQCHIP
 	select RTC_CLASS
+	select WATCHDOG_CORE
 	help
 	  Say Y here to add support for the features implemented by the
 	  microcontroller on the CZ.NIC's Turris Omnia SOHO router.
@@ -26,6 +27,7 @@ config TURRIS_OMNIA_MCU
 	  - board poweroff into true low power mode (with voltage regulators
 	    disabled) and the ability to configure wake up from this mode (via
 	    rtcwake)
+	  - MCU watchdog
 	  - GPIO pins
 	    - to get front button press events (the front button can be
 	      configured either to generate press events to the CPU or to change
diff --git a/drivers/platform/cznic/Makefile b/drivers/platform/cznic/Makefile
index a185ef882e44..687f7718c0a1 100644
--- a/drivers/platform/cznic/Makefile
+++ b/drivers/platform/cznic/Makefile
@@ -4,3 +4,4 @@ obj-$(CONFIG_TURRIS_OMNIA_MCU)	+= turris-omnia-mcu.o
 turris-omnia-mcu-y		:= turris-omnia-mcu-base.o
 turris-omnia-mcu-y		+= turris-omnia-mcu-gpio.o
 turris-omnia-mcu-y		+= turris-omnia-mcu-sys-off-wakeup.o
+turris-omnia-mcu-y		+= turris-omnia-mcu-watchdog.o
diff --git a/drivers/platform/cznic/turris-omnia-mcu-base.c b/drivers/platform/cznic/turris-omnia-mcu-base.c
index 32d187e12261..cf37c3a70497 100644
--- a/drivers/platform/cznic/turris-omnia-mcu-base.c
+++ b/drivers/platform/cznic/turris-omnia-mcu-base.c
@@ -377,6 +377,10 @@ static int omnia_mcu_probe(struct i2c_client *client)
 	if (err)
 		return err;
 
+	err = omnia_mcu_register_watchdog(mcu);
+	if (err)
+		return err;
+
 	return omnia_mcu_register_gpiochip(mcu);
 }
 
diff --git a/drivers/platform/cznic/turris-omnia-mcu-watchdog.c b/drivers/platform/cznic/turris-omnia-mcu-watchdog.c
new file mode 100644
index 000000000000..7839af66740d
--- /dev/null
+++ b/drivers/platform/cznic/turris-omnia-mcu-watchdog.c
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CZ.NIC's Turris Omnia MCU watchdog driver
+ *
+ * 2024 by Marek Behún <kabel@kernel.org>
+ */
+
+#include <linux/i2c.h>
+#include <linux/moduleparam.h>
+#include <linux/turris-omnia-mcu-interface.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+
+#include "turris-omnia-mcu.h"
+
+#define WATCHDOG_TIMEOUT		120
+
+static unsigned int timeout;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+			   __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static int omnia_wdt_start(struct watchdog_device *wdt)
+{
+	struct omnia_mcu *mcu = watchdog_get_drvdata(wdt);
+
+	return omnia_cmd_write_u8(mcu->client, OMNIA_CMD_SET_WATCHDOG_STATE, 1);
+}
+
+static int omnia_wdt_stop(struct watchdog_device *wdt)
+{
+	struct omnia_mcu *mcu = watchdog_get_drvdata(wdt);
+
+	return omnia_cmd_write_u8(mcu->client, OMNIA_CMD_SET_WATCHDOG_STATE, 0);
+}
+
+static int omnia_wdt_ping(struct watchdog_device *wdt)
+{
+	struct omnia_mcu *mcu = watchdog_get_drvdata(wdt);
+
+	return omnia_cmd_write_u8(mcu->client, OMNIA_CMD_SET_WATCHDOG_STATE, 1);
+}
+
+static int omnia_wdt_set_timeout(struct watchdog_device *wdt,
+				 unsigned int timeout)
+{
+	struct omnia_mcu *mcu = watchdog_get_drvdata(wdt);
+
+	return omnia_cmd_write_u16(mcu->client, OMNIA_CMD_SET_WDT_TIMEOUT,
+				   timeout * 10);
+}
+
+static unsigned int omnia_wdt_get_timeleft(struct watchdog_device *wdt)
+{
+	struct omnia_mcu *mcu = watchdog_get_drvdata(wdt);
+	u16 timeleft;
+	int err;
+
+	err = omnia_cmd_read_u16(mcu->client, OMNIA_CMD_GET_WDT_TIMELEFT,
+				 &timeleft);
+	if (err) {
+		dev_err(&mcu->client->dev, "Cannot get watchdog timeleft: %d\n",
+			err);
+		return 0;
+	}
+
+	return timeleft / 10;
+}
+
+static const struct watchdog_info omnia_wdt_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+	.identity = "Turris Omnia MCU Watchdog",
+};
+
+static const struct watchdog_ops omnia_wdt_ops = {
+	.owner		= THIS_MODULE,
+	.start		= omnia_wdt_start,
+	.stop		= omnia_wdt_stop,
+	.ping		= omnia_wdt_ping,
+	.set_timeout	= omnia_wdt_set_timeout,
+	.get_timeleft	= omnia_wdt_get_timeleft,
+};
+
+int omnia_mcu_register_watchdog(struct omnia_mcu *mcu)
+{
+	struct device *dev = &mcu->client->dev;
+	u8 state;
+	int err;
+
+	if (!(mcu->features & OMNIA_FEAT_WDT_PING))
+		return 0;
+
+	mcu->wdt.info = &omnia_wdt_info;
+	mcu->wdt.ops = &omnia_wdt_ops;
+	mcu->wdt.parent = dev;
+	mcu->wdt.min_timeout = 1;
+	mcu->wdt.max_timeout = 6553; /* 65535 deciseconds */
+
+	mcu->wdt.timeout = WATCHDOG_TIMEOUT;
+	watchdog_init_timeout(&mcu->wdt, timeout, dev);
+
+	watchdog_set_drvdata(&mcu->wdt, mcu);
+
+	omnia_wdt_set_timeout(&mcu->wdt, mcu->wdt.timeout);
+
+	err = omnia_cmd_read_u8(mcu->client, OMNIA_CMD_GET_WATCHDOG_STATE,
+				&state);
+	if (err)
+		return dev_err_probe(dev, err,
+				     "Cannot get MCU watchdog state\n");
+
+	if (state)
+		set_bit(WDOG_HW_RUNNING, &mcu->wdt.status);
+
+	watchdog_set_nowayout(&mcu->wdt, nowayout);
+	watchdog_stop_on_reboot(&mcu->wdt);
+	err = devm_watchdog_register_device(dev, &mcu->wdt);
+	if (err)
+		return dev_err_probe(dev, err,
+				     "Cannot register MCU watchdog\n");
+
+	return 0;
+}
diff --git a/drivers/platform/cznic/turris-omnia-mcu.h b/drivers/platform/cznic/turris-omnia-mcu.h
index 4b49736d6d3f..a5a0b55b56d4 100644
--- a/drivers/platform/cznic/turris-omnia-mcu.h
+++ b/drivers/platform/cznic/turris-omnia-mcu.h
@@ -14,6 +14,7 @@
 #include <linux/mutex.h>
 #include <linux/rtc.h>
 #include <linux/types.h>
+#include <linux/watchdog.h>
 #include <linux/workqueue.h>
 #include <asm/byteorder.h>
 #include <asm/unaligned.h>
@@ -43,6 +44,9 @@ struct omnia_mcu {
 	struct rtc_device *rtcdev;
 	u32 rtc_alarm;
 	bool front_button_poweron;
+
+	/* MCU watchdog */
+	struct watchdog_device wdt;
 };
 
 int omnia_cmd_write_read(const struct i2c_client *client,
@@ -55,6 +59,25 @@ static inline int omnia_cmd_write(const struct i2c_client *client, void *cmd,
 	return omnia_cmd_write_read(client, cmd, len, NULL, 0);
 }
 
+static inline int omnia_cmd_write_u8(const struct i2c_client *client, u8 cmd,
+				     u8 val)
+{
+	u8 buf[2] = { cmd, val };
+
+	return omnia_cmd_write(client, buf, sizeof(buf));
+}
+
+static inline int omnia_cmd_write_u16(const struct i2c_client *client, u8 cmd,
+				      u16 val)
+{
+	u8 buf[3];
+
+	buf[0] = cmd;
+	put_unaligned_le16(val, &buf[1]);
+
+	return omnia_cmd_write(client, buf, sizeof(buf));
+}
+
 static inline int omnia_cmd_write_u32(const struct i2c_client *client, u8 cmd,
 				      u32 val)
 {
@@ -151,5 +174,6 @@ extern const struct attribute_group omnia_mcu_poweroff_group;
 
 int omnia_mcu_register_gpiochip(struct omnia_mcu *mcu);
 int omnia_mcu_register_sys_off_and_wakeup(struct omnia_mcu *mcu);
+int omnia_mcu_register_watchdog(struct omnia_mcu *mcu);
 
 #endif /* __TURRIS_OMNIA_MCU_H */
-- 
2.43.2

Re: [PATCH v9 2/9] platform: cznic: Add preliminary support for Turris Omnia MCU

[Andy Shevchenko]

On Wed, May 08, 2024 at 12:31:11PM +0200, Marek Behún wrote:
> Add the basic skeleton for a new platform driver for the microcontroller
> found on the Turris Omnia board.

Some cosmetics in case you need a new version.
Possibly can be done as follow up(s).

...

> +Date:		July 2024
> +KernelVersion:	6.10

TBH, I'm not sure you manage to squeeze this rather big driver to v6.10.

...

> +static const struct attribute_group *omnia_mcu_groups[] = {
> +	&omnia_mcu_base_group,
> +	NULL
> +};

__ATTRIBUTE_GROUPS()

...

Perhaps also

	struct i2c_client *client = mcu->client;

> +	struct device *dev = &mcu->client->dev;

	struct device *dev = &client->dev;

> +	bool suggest_fw_upgrade = false;
> +	u16 status;
> +	int err;
> +
> +	/* status word holds MCU type, which we need below */
> +	err = omnia_cmd_read_u16(mcu->client, OMNIA_CMD_GET_STATUS_WORD,
> +				 &status);

	err = omnia_cmd_read_u16(client, OMNIA_CMD_GET_STATUS_WORD, &status);

and so on...


> +	if (err)
> +		return err;

...

> +	/*
> +	 * check whether MCU firmware supports the OMNIA_CMD_GET_FEATURES

Check

> +	 * command

command.

> +	 */

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v9 2/9] platform: cznic: Add preliminary support for Turris Omnia MCU

[Marek Behún]

On Wed, May 08, 2024 at 01:58:30PM +0300, Andy Shevchenko wrote:
> On Wed, May 08, 2024 at 12:31:11PM +0200, Marek Behún wrote:
> > Add the basic skeleton for a new platform driver for the microcontroller
> > found on the Turris Omnia board.
> 
> Some cosmetics in case you need a new version.
> Possibly can be done as follow up(s).
> 
> ...
> 
> > +Date:		July 2024
> > +KernelVersion:	6.10
> 
> TBH, I'm not sure you manage to squeeze this rather big driver to v6.10.
> 
> ...
> 
> > +static const struct attribute_group *omnia_mcu_groups[] = {
> > +	&omnia_mcu_base_group,
> > +	NULL
> > +};
> 
> __ATTRIBUTE_GROUPS()

I think we already discussed this one. __ATTRIBUTE_GROUPS defines only
one group, and I am adding to the array in subsequent patches.

> 
> ...
> 
> Perhaps also
> 
> 	struct i2c_client *client = mcu->client;
> 
> > +	struct device *dev = &mcu->client->dev;
> 
> 	struct device *dev = &client->dev;
> 
> > +	bool suggest_fw_upgrade = false;
> > +	u16 status;
> > +	int err;
> > +
> > +	/* status word holds MCU type, which we need below */
> > +	err = omnia_cmd_read_u16(mcu->client, OMNIA_CMD_GET_STATUS_WORD,
> > +				 &status);
> 
> 	err = omnia_cmd_read_u16(client, OMNIA_CMD_GET_STATUS_WORD, &status);
> 
> and so on...
> 
> 
> > +	if (err)
> > +		return err;
> 
> ...
> 
> > +	/*
> > +	 * check whether MCU firmware supports the OMNIA_CMD_GET_FEATURES
> 
> Check
> 
> > +	 * command
> 
> command.
> 
> > +	 */
> 
> -- 
> With Best Regards,
> Andy Shevchenko
> 
> 
> 

Re: [PATCH v9 0/9] Turris Omnia MCU driver

[Andy Shevchenko]

On Wed, May 08, 2024 at 12:31:09PM +0200, Marek Behún wrote:
> Hello Andy, Hans, Ilpo, Arnd, Gregory, and others,
> 
> this is v9 of the series adding Turris Omnia MCU driver.
> 
> This series still depends on the immutable branch between LEDs and
> locking, introducing devm_mutex_init(), see the PR
>   https://lore.kernel.org/linux-leds/20240412084616.GR2399047@google.com/
> 
> See also cover letters for v1, v2, v3, v4, v5, v6, v7 and v8:
>   https://patchwork.kernel.org/project/linux-soc/cover/20230823161012.6986-1-kabel@kernel.org/
>   https://patchwork.kernel.org/project/linux-soc/cover/20230919103815.16818-1-kabel@kernel.org/
>   https://patchwork.kernel.org/project/linux-soc/cover/20231023143130.11602-1-kabel@kernel.org/
>   https://patchwork.kernel.org/project/linux-soc/cover/20231026161803.16750-1-kabel@kernel.org/
>   https://patchwork.kernel.org/project/linux-soc/cover/20240323164359.21642-1-kabel@kernel.org/
>   https://patchwork.kernel.org/project/linux-soc/cover/20240418121116.22184-1-kabel@kernel.org/
>   https://patchwork.kernel.org/project/linux-soc/cover/20240424173809.7214-1-kabel@kernel.org/
>   https://patchwork.kernel.org/project/linux-soc/cover/20240430115111.3453-1-kabel@kernel.org/

From GPIO implementation perspective, it's good enough in my opinion. The rest
can be amended later on.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v9 5/9] platform: cznic: turris-omnia-mcu: Add support for MCU watchdog

[Andy Shevchenko]

On Wed, May 08, 2024 at 12:31:14PM +0200, Marek Behún wrote:
> Add support for the watchdog mechanism provided by the MCU.

...

> +	return omnia_cmd_write_u16(mcu->client, OMNIA_CMD_SET_WDT_TIMEOUT,
> +				   timeout * 10);

DECI (from units.h)

...

> +	return timeleft / 10;

Ditto.

...

> +	mcu->wdt.max_timeout = 6553; /* 65535 deciseconds */

Ditto.

	mcu->wdt.max_timeout = 65536 / DECI;

(and no need in a comment)

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v9 0/9] Turris Omnia MCU driver

[Marek Behún]

On Wed, May 08, 2024 at 02:17:24PM +0300, Andy Shevchenko wrote:
> On Wed, May 08, 2024 at 12:31:09PM +0200, Marek Behún wrote:
> > Hello Andy, Hans, Ilpo, Arnd, Gregory, and others,
> > 
> > this is v9 of the series adding Turris Omnia MCU driver.
> > 
> > This series still depends on the immutable branch between LEDs and
> > locking, introducing devm_mutex_init(), see the PR
> >   https://lore.kernel.org/linux-leds/20240412084616.GR2399047@google.com/
> > 
> > See also cover letters for v1, v2, v3, v4, v5, v6, v7 and v8:
> >   https://patchwork.kernel.org/project/linux-soc/cover/20230823161012.6986-1-kabel@kernel.org/
> >   https://patchwork.kernel.org/project/linux-soc/cover/20230919103815.16818-1-kabel@kernel.org/
> >   https://patchwork.kernel.org/project/linux-soc/cover/20231023143130.11602-1-kabel@kernel.org/
> >   https://patchwork.kernel.org/project/linux-soc/cover/20231026161803.16750-1-kabel@kernel.org/
> >   https://patchwork.kernel.org/project/linux-soc/cover/20240323164359.21642-1-kabel@kernel.org/
> >   https://patchwork.kernel.org/project/linux-soc/cover/20240418121116.22184-1-kabel@kernel.org/
> >   https://patchwork.kernel.org/project/linux-soc/cover/20240424173809.7214-1-kabel@kernel.org/
> >   https://patchwork.kernel.org/project/linux-soc/cover/20240430115111.3453-1-kabel@kernel.org/
> 
> From GPIO implementation perspective, it's good enough in my opinion. The rest
> can be amended later on.

I will send v10 tomorrow with these issues fixed. We'll see if Arnd will
be willing to take this for 6.10, and if not, 6.11 will it be.

Marek