[PATCH v4 2/6] hwmon: Add support for SPD5118 compliant temperature sensors

From: Guenter Roeck
Date: Tue Jun 04 2024 - 00:03:31 EST

Add support for SPD5118 (Jedec JESD300) compliant temperature
sensors. Such sensors are typically found on DDR5 memory modules.

Cc: René Rebe <rene@xxxxxxxxxxxx>
Cc: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
Reviewed-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
Tested-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
v4: No change

v3: Shorten JESD300-5B.01 to JESD300; 5B.01 refers to the version
of the standard
Drop unnecessary 'attr' parameter from spd5118_{read,write}_enable()

v2: Drop PEC property documentation
Add note indicating that alarm attributes are sticky until read
to documentation
Fix detect function
Fix misspelling in Makefile (CONFIG_SENSORS_SPD5118->CONFIG_SENSORS_SPD5118)

Documentation/hwmon/index.rst | 1 +
Documentation/hwmon/spd5118.rst | 55 ++++
drivers/hwmon/Kconfig | 12 +
drivers/hwmon/Makefile | 1 +
drivers/hwmon/spd5118.c | 481 ++++++++++++++++++++++++++++++++
5 files changed, 550 insertions(+)
create mode 100644 Documentation/hwmon/spd5118.rst
create mode 100644 drivers/hwmon/spd5118.c

diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 03d313af469a..6e7b8726b60c 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -215,6 +215,7 @@ Hardware Monitoring Kernel Drivers
smsc47m192
smsc47m1
sparx5-temp
+ spd5118
stpddc60
surface_fan
sy7636a-hwmon
diff --git a/Documentation/hwmon/spd5118.rst b/Documentation/hwmon/spd5118.rst
new file mode 100644
index 000000000000..a15d75aa2066
--- /dev/null
+++ b/Documentation/hwmon/spd5118.rst
@@ -0,0 +1,55 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver spd5118
+=====================
+
+Supported chips:
+
+ * SPD5118 (JEDEC JESD300) compliant temperature sensor chips
+
+ JEDEC standard download:
+ https://www.jedec.org/standards-documents/docs/jesd300-5b01
+ (account required)
+
+
+ Prefix: 'spd5118'
+
+ Addresses scanned: I2C 0x50 - 0x57
+
+Author:
+ Guenter Roeck <linux@xxxxxxxxxxxx>
+
+
+Description
+-----------
+
+This driver implements support for SPD5118 (JEDEC JESD300) compliant temperature
+sensors, which are used on many DDR5 memory modules. Some systems use the sensor
+to prevent memory overheating by automatically throttling the memory controller.
+
+The driver auto-detects SPD5118 compliant chips, but can also be instantiated
+using devicetree/firmware nodes.
+
+A SPD5118 compliant chip supports a single temperature sensor. Critical minimum,
+minimum, maximum, and critical temperature can be configured. There are alarms
+for low critical, low, high, and critical thresholds.
+
+
+Hardware monitoring sysfs entries
+---------------------------------
+
+======================= ==================================
+temp1_input Temperature (RO)
+temp1_lcrit Low critical high temperature (RW)
+temp1_min Minimum temperature (RW)
+temp1_max Maximum temperature (RW)
+temp1_crit Critical high temperature (RW)
+
+temp1_lcrit_alarm Temperature low critical alarm
+temp1_min_alarm Temperature low alarm
+temp1_max_alarm Temperature high alarm
+temp1_crit_alarm Temperature critical alarm
+======================= ==================================
+
+Alarm attributes are sticky until read and will be cleared afterwards
+unless the alarm condition still applies.
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index e14ae18a973b..7a84e7637b51 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -2181,6 +2181,18 @@ config SENSORS_INA3221
This driver can also be built as a module. If so, the module
will be called ina3221.

+config SENSORS_SPD5118
+ tristate "SPD5118 Compliant Temperature Sensors"
+ depends on I2C
+ select REGMAP_I2C
+ help
+ If you say yes here you get support for SPD5118 (JEDEC JESD300)
+ compliant temperature sensors. Such sensors are found on DDR5 memory
+ modules.
+
+ This driver can also be built as a module. If so, the module
+ will be called spd5118.
+
config SENSORS_TC74
tristate "Microchip TC74"
depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index e3f25475d1f0..6574ca67d761 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -207,6 +207,7 @@ obj-$(CONFIG_SENSORS_SMSC47B397)+= smsc47b397.o
obj-$(CONFIG_SENSORS_SMSC47M1) += smsc47m1.o
obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
obj-$(CONFIG_SENSORS_SPARX5) += sparx5-temp.o
+obj-$(CONFIG_SENSORS_SPD5118) += spd5118.o
obj-$(CONFIG_SENSORS_STTS751) += stts751.o
obj-$(CONFIG_SENSORS_SURFACE_FAN)+= surface_fan.o
obj-$(CONFIG_SENSORS_SY7636A) += sy7636a-hwmon.o
diff --git a/drivers/hwmon/spd5118.c b/drivers/hwmon/spd5118.c
new file mode 100644
index 000000000000..d3fc0ae17743
--- /dev/null
+++ b/drivers/hwmon/spd5118.c
@@ -0,0 +1,481 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for Jedec 5118 compliant temperature sensors
+ *
+ * Derived from https://github.com/Steve-Tech/SPD5118-DKMS
+ * Originally from T/2 driver at https://t2sde.org/packages/linux
+ * Copyright (c) 2023 René Rebe, ExactCODE GmbH; Germany.
+ *
+ * Copyright (c) 2024 Guenter Roeck
+ *
+ * Inspired by ee1004.c and jc42.c.
+ *
+ * SPD5118 compliant temperature sensors are typically used on DDR5
+ * memory modules.
+ */
+
+#include <linux/bitops.h>
+#include <linux/bits.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/units.h>
+
+/* Addresses to scan */
+static const unsigned short normal_i2c[] = {
+ 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, I2C_CLIENT_END };
+
+/* SPD5118 registers. */
+#define SPD5118_REG_TYPE 0x00 /* MR0:MR1 */
+#define SPD5118_REG_REVISION 0x02 /* MR2 */
+#define SPD5118_REG_VENDOR 0x03 /* MR3:MR4 */
+#define SPD5118_REG_CAPABILITY 0x05 /* MR5 */
+#define SPD5118_REG_I2C_LEGACY_MODE 0x0B /* MR11 */
+#define SPD5118_REG_TEMP_CLR 0x13 /* MR19 */
+#define SPD5118_REG_ERROR_CLR 0x14 /* MR20 */
+#define SPD5118_REG_TEMP_CONFIG 0x1A /* MR26 */
+#define SPD5118_REG_TEMP_MAX 0x1c /* MR28:MR29 */
+#define SPD5118_REG_TEMP_MIN 0x1e /* MR30:MR31 */
+#define SPD5118_REG_TEMP_CRIT 0x20 /* MR32:MR33 */
+#define SPD5118_REG_TEMP_LCRIT 0x22 /* MR34:MR35 */
+#define SPD5118_REG_TEMP 0x31 /* MR49:MR50 */
+#define SPD5118_REG_TEMP_STATUS 0x33 /* MR51 */
+
+#define SPD5118_TEMP_STATUS_HIGH BIT(0)
+#define SPD5118_TEMP_STATUS_LOW BIT(1)
+#define SPD5118_TEMP_STATUS_CRIT BIT(2)
+#define SPD5118_TEMP_STATUS_LCRIT BIT(3)
+
+#define SPD5118_CAP_TS_SUPPORT BIT(1) /* temperature sensor support */
+
+#define SPD5118_TS_DISABLE BIT(0) /* temperature sensor disable */
+
+/* Temperature unit in millicelsius */
+#define SPD5118_TEMP_UNIT (MILLIDEGREE_PER_DEGREE / 4)
+/* Representable temperature range in millicelsius */
+#define SPD5118_TEMP_RANGE_MIN -256000
+#define SPD5118_TEMP_RANGE_MAX 255750
+
+static int spd5118_temp_from_reg(u16 reg)
+{
+ int temp = sign_extend32(reg >> 2, 10);
+
+ return temp * SPD5118_TEMP_UNIT;
+}
+
+static u16 spd5118_temp_to_reg(long temp)
+{
+ temp = clamp_val(temp, SPD5118_TEMP_RANGE_MIN, SPD5118_TEMP_RANGE_MAX);
+ return (DIV_ROUND_CLOSEST(temp, SPD5118_TEMP_UNIT) & 0x7ff) << 2;
+}
+
+static int spd5118_read_temp(struct regmap *regmap, u32 attr, long *val)
+{
+ int reg, err;
+ u8 regval[2];
+ u16 temp;
+
+ switch (attr) {
+ case hwmon_temp_input:
+ reg = SPD5118_REG_TEMP;
+ break;
+ case hwmon_temp_max:
+ reg = SPD5118_REG_TEMP_MAX;
+ break;
+ case hwmon_temp_min:
+ reg = SPD5118_REG_TEMP_MIN;
+ break;
+ case hwmon_temp_crit:
+ reg = SPD5118_REG_TEMP_CRIT;
+ break;
+ case hwmon_temp_lcrit:
+ reg = SPD5118_REG_TEMP_LCRIT;
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ err = regmap_bulk_read(regmap, reg, regval, 2);
+ if (err)
+ return err;
+
+ temp = (regval[1] << 8) | regval[0];
+
+ *val = spd5118_temp_from_reg(temp);
+ return 0;
+}
+
+static int spd5118_read_alarm(struct regmap *regmap, u32 attr, long *val)
+{
+ unsigned int mask, regval;
+ int err;
+
+ switch (attr) {
+ case hwmon_temp_max_alarm:
+ mask = SPD5118_TEMP_STATUS_HIGH;
+ break;
+ case hwmon_temp_min_alarm:
+ mask = SPD5118_TEMP_STATUS_LOW;
+ break;
+ case hwmon_temp_crit_alarm:
+ mask = SPD5118_TEMP_STATUS_CRIT;
+ break;
+ case hwmon_temp_lcrit_alarm:
+ mask = SPD5118_TEMP_STATUS_LCRIT;
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ err = regmap_read(regmap, SPD5118_REG_TEMP_STATUS, &regval);
+ if (err < 0)
+ return err;
+ *val = !!(regval & mask);
+ if (*val)
+ return regmap_write(regmap, SPD5118_REG_TEMP_CLR, mask);
+ return 0;
+}
+
+static int spd5118_read_enable(struct regmap *regmap, long *val)
+{
+ u32 regval;
+ int err;
+
+ err = regmap_read(regmap, SPD5118_REG_TEMP_CONFIG, &regval);
+ if (err < 0)
+ return err;
+ *val = !(regval & SPD5118_TS_DISABLE);
+ return 0;
+}
+
+static int spd5118_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct regmap *regmap = dev_get_drvdata(dev);
+
+ if (type != hwmon_temp)
+ return -EOPNOTSUPP;
+
+ switch (attr) {
+ case hwmon_temp_input:
+ case hwmon_temp_max:
+ case hwmon_temp_min:
+ case hwmon_temp_crit:
+ case hwmon_temp_lcrit:
+ return spd5118_read_temp(regmap, attr, val);
+ case hwmon_temp_max_alarm:
+ case hwmon_temp_min_alarm:
+ case hwmon_temp_crit_alarm:
+ case hwmon_temp_lcrit_alarm:
+ return spd5118_read_alarm(regmap, attr, val);
+ case hwmon_temp_enable:
+ return spd5118_read_enable(regmap, val);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int spd5118_write_temp(struct regmap *regmap, u32 attr, long val)
+{
+ u8 regval[2];
+ u16 temp;
+ int reg;
+
+ switch (attr) {
+ case hwmon_temp_max:
+ reg = SPD5118_REG_TEMP_MAX;
+ break;
+ case hwmon_temp_min:
+ reg = SPD5118_REG_TEMP_MIN;
+ break;
+ case hwmon_temp_crit:
+ reg = SPD5118_REG_TEMP_CRIT;
+ break;
+ case hwmon_temp_lcrit:
+ reg = SPD5118_REG_TEMP_LCRIT;
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ temp = spd5118_temp_to_reg(val);
+ regval[0] = temp & 0xff;
+ regval[1] = temp >> 8;
+
+ return regmap_bulk_write(regmap, reg, regval, 2);
+}
+
+static int spd5118_write_enable(struct regmap *regmap, long val)
+{
+ if (val && val != 1)
+ return -EINVAL;
+
+ return regmap_update_bits(regmap, SPD5118_REG_TEMP_CONFIG,
+ SPD5118_TS_DISABLE,
+ val ? 0 : SPD5118_TS_DISABLE);
+}
+
+static int spd5118_temp_write(struct regmap *regmap, u32 attr, long val)
+{
+ switch (attr) {
+ case hwmon_temp_max:
+ case hwmon_temp_min:
+ case hwmon_temp_crit:
+ case hwmon_temp_lcrit:
+ return spd5118_write_temp(regmap, attr, val);
+ case hwmon_temp_enable:
+ return spd5118_write_enable(regmap, val);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int spd5118_write(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long val)
+{
+ struct regmap *regmap = dev_get_drvdata(dev);
+
+ switch (type) {
+ case hwmon_temp:
+ return spd5118_temp_write(regmap, attr, val);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static umode_t spd5118_is_visible(const void *_data, enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ if (type != hwmon_temp)
+ return 0;
+
+ switch (attr) {
+ case hwmon_temp_input:
+ return 0444;
+ case hwmon_temp_min:
+ case hwmon_temp_max:
+ case hwmon_temp_lcrit:
+ case hwmon_temp_crit:
+ case hwmon_temp_enable:
+ return 0644;
+ case hwmon_temp_min_alarm:
+ case hwmon_temp_max_alarm:
+ case hwmon_temp_crit_alarm:
+ case hwmon_temp_lcrit_alarm:
+ return 0444;
+ default:
+ return 0;
+ }
+}
+
+static inline bool spd5118_parity8(u8 w)
+{
+ w ^= w >> 4;
+ return (0x6996 >> (w & 0xf)) & 1;
+}
+
+/*
+ * Bank and vendor id are 8-bit fields with seven data bits and odd parity.
+ * Vendor IDs 0 and 0x7f are invalid.
+ * See Jedec standard JEP106BJ for details and a list of assigned vendor IDs.
+ */
+static bool spd5118_vendor_valid(u8 bank, u8 id)
+{
+ if (!spd5118_parity8(bank) || !spd5118_parity8(id))
+ return false;
+
+ id &= 0x7f;
+ return id && id != 0x7f;
+}
+
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static int spd5118_detect(struct i2c_client *client, struct i2c_board_info *info)
+{
+ struct i2c_adapter *adapter = client->adapter;
+ int regval;
+
+ if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
+ I2C_FUNC_SMBUS_WORD_DATA))
+ return -ENODEV;
+
+ regval = i2c_smbus_read_word_swapped(client, SPD5118_REG_TYPE);
+ if (regval != 0x5118)
+ return -ENODEV;
+
+ regval = i2c_smbus_read_word_data(client, SPD5118_REG_VENDOR);
+ if (regval < 0 || !spd5118_vendor_valid(regval & 0xff, regval >> 8))
+ return -ENODEV;
+
+ regval = i2c_smbus_read_byte_data(client, SPD5118_REG_CAPABILITY);
+ if (regval < 0)
+ return -ENODEV;
+ if (!(regval & SPD5118_CAP_TS_SUPPORT) || (regval & 0xfc))
+ return -ENODEV;
+
+ regval = i2c_smbus_read_byte_data(client, SPD5118_REG_TEMP_CLR);
+ if (regval)
+ return -ENODEV;
+ regval = i2c_smbus_read_byte_data(client, SPD5118_REG_ERROR_CLR);
+ if (regval)
+ return -ENODEV;
+
+ regval = i2c_smbus_read_byte_data(client, SPD5118_REG_REVISION);
+ if (regval < 0 || (regval & 0xc1))
+ return -ENODEV;
+
+ regval = i2c_smbus_read_byte_data(client, SPD5118_REG_TEMP_CONFIG);
+ if (regval < 0)
+ return -ENODEV;
+ if (regval & ~SPD5118_TS_DISABLE)
+ return -ENODEV;
+
+ strscpy(info->type, "spd5118", I2C_NAME_SIZE);
+ return 0;
+}
+
+static const struct hwmon_channel_info *spd5118_info[] = {
+ HWMON_CHANNEL_INFO(chip,
+ HWMON_C_REGISTER_TZ),
+ HWMON_CHANNEL_INFO(temp,
+ HWMON_T_INPUT |
+ HWMON_T_LCRIT | HWMON_T_LCRIT_ALARM |
+ HWMON_T_MIN | HWMON_T_MIN_ALARM |
+ HWMON_T_MAX | HWMON_T_MAX_ALARM |
+ HWMON_T_CRIT | HWMON_T_CRIT_ALARM |
+ HWMON_T_ENABLE),
+ NULL
+};
+
+static const struct hwmon_ops spd5118_hwmon_ops = {
+ .is_visible = spd5118_is_visible,
+ .read = spd5118_read,
+ .write = spd5118_write,
+};
+
+static const struct hwmon_chip_info spd5118_chip_info = {
+ .ops = &spd5118_hwmon_ops,
+ .info = spd5118_info,
+};
+
+static bool spd5118_writeable_reg(struct device *dev, unsigned int reg)
+{
+ switch (reg) {
+ case SPD5118_REG_TEMP_CLR:
+ case SPD5118_REG_TEMP_CONFIG:
+ case SPD5118_REG_TEMP_MAX:
+ case SPD5118_REG_TEMP_MAX + 1:
+ case SPD5118_REG_TEMP_MIN:
+ case SPD5118_REG_TEMP_MIN + 1:
+ case SPD5118_REG_TEMP_CRIT:
+ case SPD5118_REG_TEMP_CRIT + 1:
+ case SPD5118_REG_TEMP_LCRIT:
+ case SPD5118_REG_TEMP_LCRIT + 1:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static bool spd5118_volatile_reg(struct device *dev, unsigned int reg)
+{
+ switch (reg) {
+ case SPD5118_REG_TEMP_CLR:
+ case SPD5118_REG_ERROR_CLR:
+ case SPD5118_REG_TEMP:
+ case SPD5118_REG_TEMP + 1:
+ case SPD5118_REG_TEMP_STATUS:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static const struct regmap_config spd5118_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = SPD5118_REG_TEMP_STATUS,
+ .writeable_reg = spd5118_writeable_reg,
+ .volatile_reg = spd5118_volatile_reg,
+ .cache_type = REGCACHE_MAPLE,
+};
+
+static int spd5118_probe(struct i2c_client *client)
+{
+ struct device *dev = &client->dev;
+ unsigned int regval, revision, vendor, bank;
+ struct device *hwmon_dev;
+ struct regmap *regmap;
+ int err;
+
+ regmap = devm_regmap_init_i2c(client, &spd5118_regmap_config);
+ if (IS_ERR(regmap))
+ return dev_err_probe(dev, PTR_ERR(regmap), "regmap init failed\n");
+
+ err = regmap_read(regmap, SPD5118_REG_CAPABILITY, &regval);
+ if (err)
+ return err;
+ if (!(regval & SPD5118_CAP_TS_SUPPORT))
+ return -ENODEV;
+
+ err = regmap_read(regmap, SPD5118_REG_REVISION, &revision);
+ if (err)
+ return err;
+
+ err = regmap_read(regmap, SPD5118_REG_VENDOR, &bank);
+ if (err)
+ return err;
+ err = regmap_read(regmap, SPD5118_REG_VENDOR + 1, &vendor);
+ if (err)
+ return err;
+ if (!spd5118_vendor_valid(bank, vendor))
+ return -ENODEV;
+
+ hwmon_dev = devm_hwmon_device_register_with_info(dev, "spd5118",
+ regmap, &spd5118_chip_info,
+ NULL);
+ if (IS_ERR(hwmon_dev))
+ return PTR_ERR(hwmon_dev);
+
+ /*
+ * From JESD300-5B
+ * MR2 bits [5:4]: Major revision, 1..4
+ * MR2 bits [3:1]: Minor revision, 0..8? Probably a typo, assume 1..8
+ */
+ dev_info(dev, "DDR5 temperature sensor: vendor 0x%02x:0x%02x revision %d.%d\n",
+ bank & 0x7f, vendor, ((revision >> 4) & 0x03) + 1, ((revision >> 1) & 0x07) + 1);
+
+ return 0;
+}
+
+static const struct i2c_device_id spd5118_id[] = {
+ { "spd5118", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, spd5118_id);
+
+static const struct of_device_id spd5118_of_ids[] = {
+ { .compatible = "jedec,spd5118", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, spd5118_of_ids);
+
+static struct i2c_driver spd5118_driver = {
+ .class = I2C_CLASS_HWMON,
+ .driver = {
+ .name = "spd5118",
+ .of_match_table = spd5118_of_ids,
+ },
+ .probe = spd5118_probe,
+ .id_table = spd5118_id,
+ .detect = spd5118_detect,
+ .address_list = normal_i2c,
+};
+
+module_i2c_driver(spd5118_driver);
+
+MODULE_AUTHOR("René Rebe <rene@xxxxxxxxxxxx>");
+MODULE_AUTHOR("Guenter Roeck <linux@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("SPD 5118 driver");
+MODULE_LICENSE("GPL");
--
2.39.2