@@ -1487,6 +1487,16 @@ config SENSORS_RASPBERRYPI_HWMON
This driver can also be built as a module. If so, the module
will be called raspberrypi-hwmon.
+config SENSORS_SBTSI
+ tristate "Emulated SB-TSI temperature sensor"
+ depends on I2C
+ help
+ If you say yes here you get support for emulated temperature
+ sensors on AMD SoCs with SB-TSI interface connected to a BMC device.
+
+ This driver can also be built as a module. If so, the module will
+ be called sbtsi_temp.
+
config SENSORS_SHT15
tristate "Sensiron humidity and temperature sensors. SHT15 and compat."
depends on GPIOLIB || COMPILE_TEST
@@ -157,6 +157,7 @@ obj-$(CONFIG_SENSORS_POWR1220) += powr1220.o
obj-$(CONFIG_SENSORS_PWM_FAN) += pwm-fan.o
obj-$(CONFIG_SENSORS_RASPBERRYPI_HWMON) += raspberrypi-hwmon.o
obj-$(CONFIG_SENSORS_S3C) += s3c-hwmon.o
+obj-$(CONFIG_SENSORS_SBTSI) += sbtsi_temp.o
obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o
obj-$(CONFIG_SENSORS_SCH5627) += sch5627.o
obj-$(CONFIG_SENSORS_SCH5636) += sch5636.o
new file mode 100644
@@ -0,0 +1,250 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * sbtsi_temp.c - hwmon driver for a SBI Temperature Sensor Interface (SB-TSI)
+ * compliant AMD SoC temperature device.
+ *
+ * Copyright (c) 2020, Google Inc.
+ * Copyright (c) 2020, Kun Yi <kunyi@google.com>
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/hwmon.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_device.h>
+#include <linux/of.h>
+
+/*
+ * SB-TSI registers only support SMBus byte data access. "_INT" registers are
+ * the integer part of a temperature value or limit, and "_DEC" registers are
+ * corresponding decimal parts.
+ */
+#define SBTSI_REG_TEMP_INT 0x01 /* RO */
+#define SBTSI_REG_STATUS 0x02 /* RO */
+#define SBTSI_REG_CONFIG 0x03 /* RO */
+#define SBTSI_REG_TEMP_HIGH_INT 0x07 /* RW */
+#define SBTSI_REG_TEMP_LOW_INT 0x08 /* RW */
+#define SBTSI_REG_TEMP_DEC 0x10 /* RW */
+#define SBTSI_REG_TEMP_HIGH_DEC 0x13 /* RW */
+#define SBTSI_REG_TEMP_LOW_DEC 0x14 /* RW */
+
+#define SBTSI_CONFIG_READ_ORDER_SHIFT 5
+
+#define SBTSI_TEMP_MIN 0
+#define SBTSI_TEMP_MAX 255875
+
+/* Each client has this additional data */
+struct sbtsi_data {
+ struct i2c_client *client;
+ struct mutex lock;
+};
+
+/*
+ * From SB-TSI spec: CPU temperature readings and limit registers encode the
+ * temperature in increments of 0.125 from 0 to 255.875. The "high byte"
+ * register encodes the base-2 of the integer portion, and the upper 3 bits of
+ * the "low byte" encode in base-2 the decimal portion.
+ *
+ * e.g. INT=0x19, DEC=0x20 represents 25.125 degrees Celsius
+ *
+ * Therefore temperature in millidegree Celsius =
+ * (INT + DEC / 256) * 1000 = (INT * 8 + DEC / 32) * 125
+ */
+static inline int sbtsi_reg_to_mc(s32 integer, s32 decimal)
+{
+ return ((integer << 3) + (decimal >> 5)) * 125;
+}
+
+/*
+ * Inversely, given temperature in millidegree Celsius
+ * INT = (TEMP / 125) / 8
+ * DEC = ((TEMP / 125) % 8) * 32
+ * Caller have to make sure temp doesn't exceed 255875, the max valid value.
+ */
+static inline void sbtsi_mc_to_reg(s32 temp, u8 *integer, u8 *decimal)
+{
+ temp /= 125;
+ *integer = temp >> 3;
+ *decimal = (temp & 0x7) << 5;
+}
+
+static int sbtsi_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct sbtsi_data *data = dev_get_drvdata(dev);
+ s32 temp_int, temp_dec;
+ int err;
+
+ switch (attr) {
+ case hwmon_temp_input:
+ /*
+ * ReadOrder bit specifies the reading order of integer and
+ * decimal part of CPU temp for atomic reads. If bit == 0,
+ * reading integer part triggers latching of the decimal part,
+ * so integer part should be read first. If bit == 1, read
+ * order should be reversed.
+ */
+ err = i2c_smbus_read_byte_data(data->client, SBTSI_REG_CONFIG);
+ if (err < 0)
+ return err;
+
+ mutex_lock(&data->lock);
+ if (err & BIT(SBTSI_CONFIG_READ_ORDER_SHIFT)) {
+ temp_dec = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_DEC);
+ temp_int = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_INT);
+ } else {
+ temp_int = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_INT);
+ temp_dec = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_DEC);
+ }
+ mutex_unlock(&data->lock);
+ break;
+ case hwmon_temp_max:
+ mutex_lock(&data->lock);
+ temp_int = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_HIGH_INT);
+ temp_dec = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_HIGH_DEC);
+ mutex_unlock(&data->lock);
+ break;
+ case hwmon_temp_min:
+ mutex_lock(&data->lock);
+ temp_int = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_LOW_INT);
+ temp_dec = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_LOW_DEC);
+ mutex_unlock(&data->lock);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+
+ if (temp_int < 0)
+ return temp_int;
+ if (temp_dec < 0)
+ return temp_dec;
+
+ *val = sbtsi_reg_to_mc(temp_int, temp_dec);
+
+ return 0;
+}
+
+static int sbtsi_write(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long val)
+{
+ struct sbtsi_data *data = dev_get_drvdata(dev);
+ int reg_int, reg_dec, err;
+ u8 temp_int, temp_dec;
+
+ switch (attr) {
+ case hwmon_temp_max:
+ reg_int = SBTSI_REG_TEMP_HIGH_INT;
+ reg_dec = SBTSI_REG_TEMP_HIGH_DEC;
+ break;
+ case hwmon_temp_min:
+ reg_int = SBTSI_REG_TEMP_LOW_INT;
+ reg_dec = SBTSI_REG_TEMP_LOW_DEC;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ val = clamp_val(val, SBTSI_TEMP_MIN, SBTSI_TEMP_MAX);
+ sbtsi_mc_to_reg(val, &temp_int, &temp_dec);
+
+ mutex_lock(&data->lock);
+ err = i2c_smbus_write_byte_data(data->client, reg_int, temp_int);
+ if (err)
+ goto exit;
+
+ err = i2c_smbus_write_byte_data(data->client, reg_dec, temp_dec);
+exit:
+ mutex_unlock(&data->lock);
+ return err;
+}
+
+static umode_t sbtsi_is_visible(const void *data,
+ enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ switch (type) {
+ case hwmon_temp:
+ switch (attr) {
+ case hwmon_temp_input:
+ return 0444;
+ case hwmon_temp_min:
+ return 0644;
+ case hwmon_temp_max:
+ return 0644;
+ }
+ break;
+ default:
+ break;
+ }
+ return 0;
+}
+
+static const struct hwmon_channel_info *sbtsi_info[] = {
+ HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
+ HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX),
+ NULL
+};
+
+static const struct hwmon_ops sbtsi_hwmon_ops = {
+ .is_visible = sbtsi_is_visible,
+ .read = sbtsi_read,
+ .write = sbtsi_write,
+};
+
+static const struct hwmon_chip_info sbtsi_chip_info = {
+ .ops = &sbtsi_hwmon_ops,
+ .info = sbtsi_info,
+};
+
+static int sbtsi_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct device *dev = &client->dev;
+ struct device *hwmon_dev;
+ struct sbtsi_data *data;
+
+ data = devm_kzalloc(dev, sizeof(struct sbtsi_data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->client = client;
+ mutex_init(&data->lock);
+
+ hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data, &sbtsi_chip_info,
+ NULL);
+
+ return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id sbtsi_id[] = {
+ {"sbtsi", 0},
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, sbtsi_id);
+
+static const struct of_device_id __maybe_unused sbtsi_of_match[] = {
+ {
+ .compatible = "amd,sbtsi",
+ },
+ { },
+};
+MODULE_DEVICE_TABLE(of, sbtsi_of_match);
+
+static struct i2c_driver sbtsi_driver = {
+ .class = I2C_CLASS_HWMON,
+ .driver = {
+ .name = "sbtsi",
+ .of_match_table = of_match_ptr(sbtsi_of_match),
+ },
+ .probe = sbtsi_probe,
+ .id_table = sbtsi_id,
+};
+
+module_i2c_driver(sbtsi_driver);
+
+MODULE_AUTHOR("Kun Yi <kunyi@google.com>");
+MODULE_DESCRIPTION("Hwmon driver for AMD SB-TSI emulated sensor");
+MODULE_LICENSE("GPL");