On Mon, Aug 05, 2024 at 09:38:03AM GMT, Chen Wang wrote:

On 2024/8/2 20:38, Inochi Amaoto wrote:

quoted

SG2042 use an external MCU to provide basic hardware information
and thermal sensors.

Add driver support for the onboard MCU of SG2042.

Signed-off-by: Inochi Amaoto <redacted>
Tested-by: Chen Wang <redacted>
Reviewed-by: Chen Wang <redacted>
---
  Documentation/hwmon/index.rst      |   1 +
  Documentation/hwmon/sg2042-mcu.rst |  39 +++
  drivers/hwmon/Kconfig              |  11 +
  drivers/hwmon/Makefile             |   1 +
  drivers/hwmon/sg2042-mcu.c         | 394 +++++++++++++++++++++++++++++
  5 files changed, 446 insertions(+)
  create mode 100644 Documentation/hwmon/sg2042-mcu.rst
  create mode 100644 drivers/hwmon/sg2042-mcu.c

diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 913c11390a45..ea3b5be8fe4f 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst

@@ -206,6 +206,7 @@ Hardware Monitoring Kernel Drivers
     sch5636
     scpi-hwmon
     sfctemp
+   sg2042-mcu
     sht15
     sht21
     sht3x

diff --git a/Documentation/hwmon/sg2042-mcu.rst b/Documentation/hwmon/sg2042-mcu.rst
new file mode 100644
index 000000000000..250016b47dd1
--- /dev/null
+++ b/Documentation/hwmon/sg2042-mcu.rst

@@ -0,0 +1,39 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver sg2042-mcu
+=====================
+
+Supported chips:
+
+  * Onboard MCU for sg2042
+
+    Addresses scanned: -
+
+    Prefix: 'sg2042-mcu'
+
+Authors:
+
+  - Inochi Amaoto <inochiama@outlook.com>
+
+Description
+-----------
+
+This driver supprts hardware monitoring for onboard MCU with
+i2c interface.
+
+Usage Notes
+-----------
+
+This driver does not auto-detect devices. You will have to instantiate
+the devices explicitly.
+Please see Documentation/i2c/instantiating-devices.rst for details.
+
+Sysfs Attributes
+----------------
+
+================= =============================================
+temp1_input       Measured temperature of SoC
+temp1_crit        Critical high temperature
+temp1_crit_hyst   hysteresis temperature restore from Critical
+temp2_input       Measured temperature of the base board
+================= =============================================

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index b60fe2e58ad6..7aa6c3f322e5 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig

@@ -2066,6 +2066,17 @@ config SENSORS_SFCTEMP
  	  This driver can also be built as a module.  If so, the module
  	  will be called sfctemp.
+config SENSORS_SG2042_MCU
+	tristate "Sophgo onboard MCU support"
+	depends on I2C
+	depends on ARCH_SOPHGO || COMPILE_TEST
+	help
+	  Support for onboard MCU of Sophgo SG2042 SoCs. This mcu provides
+	  power control and some basic information.
+
+	  This driver can be built as a module. If so, the module
+	  will be called sg2042-mcu.
+
  config SENSORS_SURFACE_FAN
  	tristate "Surface Fan Driver"
  	depends on SURFACE_AGGREGATOR

diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index b1c7056c37db..0bbe812a67ae 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile

@@ -194,6 +194,7 @@ obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o
  obj-$(CONFIG_SENSORS_SCH5627)	+= sch5627.o
  obj-$(CONFIG_SENSORS_SCH5636)	+= sch5636.o
  obj-$(CONFIG_SENSORS_SFCTEMP)	+= sfctemp.o
+obj-$(CONFIG_SENSORS_SG2042_MCU) += sg2042-mcu.o
  obj-$(CONFIG_SENSORS_SL28CPLD)	+= sl28cpld-hwmon.o
  obj-$(CONFIG_SENSORS_SHT15)	+= sht15.o
  obj-$(CONFIG_SENSORS_SHT21)	+= sht21.o

diff --git a/drivers/hwmon/sg2042-mcu.c b/drivers/hwmon/sg2042-mcu.c
new file mode 100644
index 000000000000..6d8d677f86f3
--- /dev/null
+++ b/drivers/hwmon/sg2042-mcu.c

@@ -0,0 +1,394 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2024 Inochi Amaoto <inochiama@outlook.com>
+ *
+ * Sophgo power control mcu for SG2042
+ */
+
+#include <linux/cleanup.h>
+#include <linux/debugfs.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+
+/* fixed MCU registers */
+#define REG_BOARD_TYPE				0x00
+#define REG_MCU_FIRMWARE_VERSION		0x01
+#define REG_PCB_VERSION				0x02
+#define REG_PWR_CTRL				0x03
+#define REG_SOC_TEMP				0x04
+#define REG_BOARD_TEMP				0x05
+#define REG_RST_COUNT				0x0a
+#define REG_UPTIME				0x0b
+#define REG_RESET_REASON			0x0d
+#define REG_MCU_TYPE				0x18
+#define REG_REPOWER_ACTION			0x65
+#define REG_CRITICAL_TEMP			0x66
+#define REG_REPOWER_TEMP			0x67

As I mentioend in last review, suggest to add some clarification for
CRITICAL and REPOWER. Due to no document from sophgo, I hope some comments
in code for memo.

After some struggle, I find it is hard to add some comments here. 
It is useless and the code should be self-explained. Instead, I 
add the comment in the document and rename this reg to "repower 
policy" to make it clear. See it in the next version.

Regards,
Inochi