kmods: leh800b: uploaded first version of MSPM0 ADC sensor

kmods/leh800b/Makefile

@@ -5,4 +5,6 @@
 obj-m += leh800b_pdbcpld.o
 leh800b_pdbcpld-objs := leh800b/leh800b_pdbcpld_i2c.o lib/regbit-sysfs.o fboss_iob_led_trigger.o
 obj-m += leh800b_scmcpld.o
-leh800b_scmcpld-objs := leh800b/leh800b_scmcpld_i2c.o lib/regbit-sysfs.o fboss_iob_led_trigger.o
+leh800b_scmcpld-objs := leh800b/leh800b_scmcpld_i2c.o lib/regbit-sysfs.o fboss_iob_led_trigger.o
+obj-m += mspm0.o
+mspm0-objs := leh800b/mspm0.o

kmods/leh800b/mspm0.c

@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright (c) Meta Platforms, Inc. and affiliates.
+
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/swab.h>
+
+#define DRIVER_NAME "mspm0"
+
+/*
+ * The formula of 12-bit value (N) from ADC reading is
+ * N = (2^n-1) * (V_in-0.5LSB) / V_ref
+ * where LSB = V_ref / (2^n), n = 12
+ * V_ref is based on the SMB schematic, 3.3 * 10 / 13.2 = 2.5V
+ * Use V_in(N) = 2500 * N / 2^n approximate for SAR core
+ */
+#define ADC_RESOLUTION_BIT 12U
+#define ADC_V_REF 2500U
+#define ADC_VIN(N) (ADC_V_REF * (N) / (1U << ADC_RESOLUTION_BIT))
+
+/*
+ * Number of ADC channels (Registers 0x00 to 0x15)
+ * CH4(A0_4) is not exposed on the register design.
+ * 0x0a <-> CH11(A0_11) is occupied for other usage.
+ * 0x15 <-> CH29 is a temp sensor that is not used in this driver.
+ */
+#define MSPM0_NUM_CHANNELS 22
+#define MSPM0_ADC_SKIPPED_CH 4
+#define MSPM0_ADC_UNUSED_CH 12
+
+static const int mspm0_adc_reg_map[] = {
+	0x00, 0x01, 0x02, 0x03,
+	  -1, 0x04, 0x05, 0x06,
+	0x07, 0x08, 0x09, 0x0a,
+	0x0b, 0x0c, 0x0d, 0x0e,
+	0x0f, 0x10, 0x11, 0x12,
+	0x13, 0x14,
+};
+
+static int mspm0_read(struct device *dev, enum hwmon_sensor_types type,
+		      u32 attr, int channel, long *val)
+{
+	struct i2c_client *client = dev_get_drvdata(dev);
+	int ret;
+	int reg;
+	u16 val_raw;
+
+	if (type != hwmon_in || attr != hwmon_in_input)
+		return -EOPNOTSUPP;
+
+	/*
+	 * A0_4 and A0_12 should not be used.
+	 */
+	switch (channel) {
+	case MSPM0_ADC_SKIPPED_CH:
+	case MSPM0_ADC_UNUSED_CH:
+		return -EINVAL;
+	}
+
+	if (channel < 0 || channel > MSPM0_NUM_CHANNELS)
+		return -EINVAL;
+
+	reg = mspm0_adc_reg_map[channel];
+
+	/*
+	 * PEC is handled automatically by the I2C adapter since we
+	 * set I2C_CLIENT_PEC in the probe function.
+	 */
+	ret = i2c_smbus_read_word_data(client, reg);
+	if (ret < 0)
+		return ret;
+
+	/* Swap bytes to change endianess */
+	val_raw = swab16((u16)ret);
+	/* Filter out hardware glitches */
+	if (unlikely(val_raw > (1<<ADC_RESOLUTION_BIT) - 1))
+		val_raw = (1<<ADC_RESOLUTION_BIT) - 1;
+
+	/* Apply the requested formula and change to voltage value. */
+	*val = ADC_VIN((long)val_raw);
+
+	return 0;
+}
+
+static umode_t mspm0_is_visible(const void *data,
+				enum hwmon_sensor_types type,
+				u32 attr, int channel)
+{
+	switch (channel) {
+	case MSPM0_ADC_SKIPPED_CH:
+	case MSPM0_ADC_UNUSED_CH:
+		return 0;
+	}
+
+	if (type == hwmon_in && attr == hwmon_in_input)
+		return 0444; /* Read-only permissions */
+
+	return 0;
+}
+
+static const struct hwmon_ops mspm0_hwmon_ops = {
+	.is_visible = mspm0_is_visible,
+	.read = mspm0_read,
+};
+
+/*
+ * Declare 22 input channels.
+ * This creates sysfs entries from in0_input to in21_input
+ * and skips in4 and in12.
+ */
+static const struct hwmon_channel_info *mspm0_info[] = {
+	HWMON_CHANNEL_INFO(in,
+		HWMON_I_INPUT, HWMON_I_INPUT, HWMON_I_INPUT, HWMON_I_INPUT,
+		HWMON_I_INPUT, HWMON_I_INPUT, HWMON_I_INPUT, HWMON_I_INPUT,
+		HWMON_I_INPUT, HWMON_I_INPUT, HWMON_I_INPUT, HWMON_I_INPUT,
+		HWMON_I_INPUT, HWMON_I_INPUT, HWMON_I_INPUT, HWMON_I_INPUT,
+		HWMON_I_INPUT, HWMON_I_INPUT, HWMON_I_INPUT, HWMON_I_INPUT,
+		HWMON_I_INPUT, HWMON_I_INPUT),
+	NULL
+};
+
+static const struct hwmon_chip_info mspm0_chip_info = {
+	.ops = &mspm0_hwmon_ops,
+	.info = mspm0_info,
+};
+
+static int mspm0_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct device *hwmon_dev;
+
+	/* * Check if the I2C adapter supports SMBus Word Data reads and PEC.
+	 */
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_READ_WORD_DATA | I2C_FUNC_SMBUS_PEC)) {
+		dev_err(dev, "I2C adapter doesn't support SMBus Word Read with PEC\n");
+		return -ENODEV;
+	}
+
+	/* Force Packet Error Checking (PEC) for all SMBus transactions */
+	client->flags |= I2C_CLIENT_PEC;
+
+	/* * Register the hwmon device. We pass 'client' as drvdata so we can
+	 * retrieve it easily in the mspm0_read() callback.
+	 */
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
+							 client,
+							 &mspm0_chip_info,
+							 NULL);
+
+	if (IS_ERR(hwmon_dev))
+		return dev_err_probe(dev, PTR_ERR(hwmon_dev),
+				     "Failed to register hwmon device\n");
+
+	return 0;
+}
+
+/* Standard I2C Matching */
+static const struct i2c_device_id mspm0_id[] = {
+	{ DRIVER_NAME, 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, mspm0_id);
+
+static struct i2c_driver mspm0_driver = {
+	.class		= I2C_CLASS_HWMON,
+	.driver = {
+		.name = DRIVER_NAME,
+	},
+	.probe		= mspm0_probe,
+	.id_table	= mspm0_id,
+};
+
+module_i2c_driver(mspm0_driver);
+
+MODULE_AUTHOR("Evan Zong <ezong@celestica.com>");
+MODULE_DESCRIPTION("Hwmon driver for TI MSPM0 voltage monitor");
+MODULE_LICENSE("GPL");

kmods/scripts/kmods.json

@@ -43,6 +43,7 @@
         "mp3_smbcpld",
         "mp3n_fancpld",
         "mp3n_scmcpld",
+        "mspm0",
         "mtia_fan_watchdog",
         "mtia_smbcpld",
         "tahansb_fancpld",