[PATCH v5 0/6] hwmon: Add support for SPD5118 compliant chips

[PATCH v5 0/6] hwmon: Add support for SPD5118 compliant chips

[Guenter Roeck]

Add support for SPD5118 (Jedec JESD300) compliant chips supporting
a temperature sensor and SPD NVRAM. Such devices are typically found on
DDR5 memory modules.

The first patch of the series adds SPD5118 devicetree bindings. The second
patch adds support for SPD5118 temperature sensors. The third patch adds
support for suspend/resume. The 4th patch adds support for reading the
SPD NVRAM. The 5th patch adds support for auto-detecting SPD5118 compliant
chips to i2c_register_spd() in the i2c-smbus code. The last patch of the
series adds a configuration option to make the auto-detect code in the
spd5118 driver configurable.

Note: The driver introduced with this patch series does not currently
support accessing SPD5118 compliant chips in I3C mode.

v5: Added Tested-by: tags
    Cosmetic changes
    Added reference to LPDDR5 to subject and description of patch 5/6
    Updated comments associated with i2c_register_spd()
    to include support for (LP)DDR5
    Replaced #ifdef with IS_ENABLED() and included address_list in
    conditional code of patch 6/6

v4: Add support for detecting SPD5118 compliant chips in i2c-smbus driver
    Make auto-detect code in driver optional
    Fix suspend code
    Ignore failure to register with nvmem core if it is disabled
    Use NVMEM_DEVID_NONE instead of NVMEM_DEVID_AUTO in nvmem code,
    changing nvmem attribute directories from 0-005[0-7]X to 0-005[0-7]

v3: Drop explicit bindings document; add binding to trivial devices instead
    Add support for reading SPD NVRAM

v2: Drop PEC support; it only applies to I3C mode.
    Update documentation
    Add suspend/resume support 

----------------------------------------------------------------
Guenter Roeck (6):
      dt-bindings: trivial-devices: Add jedec,spd5118
      hwmon: Add support for SPD5118 compliant temperature sensors
      hwmon: (spd5118) Add suspend/resume support
      hwmon: (spd5118) Add support for reading SPD data
      i2c: smbus: Support DDR5 and LPDDR5 SPD EEPROMs
      hwmon: (spd5118) Add configuration option for auto-detection

 .../devicetree/bindings/trivial-devices.yaml       |   2 +
 Documentation/hwmon/index.rst                      |   1 +
 Documentation/hwmon/spd5118.rst                    |  63 ++
 drivers/hwmon/Kconfig                              |  31 +
 drivers/hwmon/Makefile                             |   1 +
 drivers/hwmon/spd5118.c                            | 658 +++++++++++++++++++++
 drivers/i2c/i2c-smbus.c                            |   6 +-
 7 files changed, 761 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/hwmon/spd5118.rst
 create mode 100644 drivers/hwmon/spd5118.c

[PATCH v5 1/6] dt-bindings: trivial-devices: Add jedec,spd5118

[Guenter Roeck]

Add bindings for the SPD hub present in DDR5 modules.
(https://www.jedec.org/standards-documents/docs/jesd300-5b01).

Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v5: Unchanged

v4: Add Krzysztof's Acked-by:

v3: Drop explicit bindings file; add binding to trivial devices
    instead

 Documentation/devicetree/bindings/trivial-devices.yaml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/trivial-devices.yaml b/Documentation/devicetree/bindings/trivial-devices.yaml
index 0a419453d183..1d19e67de2a1 100644
--- a/Documentation/devicetree/bindings/trivial-devices.yaml
+++ b/Documentation/devicetree/bindings/trivial-devices.yaml
@@ -168,6 +168,8 @@ properties:
           - isil,isl69269
             # Intersil ISL76682 Ambient Light Sensor
           - isil,isl76682
+            # JEDEC JESD300 (SPD5118) Hub and Serial Presence Detect
+          - jedec,spd5118
             # Linear Technology LTC2488
           - lineartechnology,ltc2488
             # 5 Bit Programmable, Pulse-Width Modulator
-- 
2.39.2

[PATCH v5 2/6] hwmon: Add support for SPD5118 compliant temperature sensors

[Guenter Roeck]

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

Cc: René Rebe <rene@exactcode.de>
Cc: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Tested-by: Thomas Weißschuh <linux@weissschuh.net>
Tested-by: Stephen Horvath <s.horvath@outlook.com.au>
Tested-by: Armin Wolf <W_Armin@gmx.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v5: Added Tested-by: tags

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@roeck-us.net>
+
+
+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@exactcode.de>");
+MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
+MODULE_DESCRIPTION("SPD 5118 driver");
+MODULE_LICENSE("GPL");
-- 
2.39.2

[PATCH v5 3/6] hwmon: (spd5118) Add suspend/resume support

[Guenter Roeck]

Add suspend/resume support to ensure that limit and configuration
registers are updated and synchronized after a suspend/resume cycle.

Cc: Armin Wolf <W_Armin@gmx.de>
Cc: Stephen Horvath <s.horvath@outlook.com.au>
Tested-by: Stephen Horvath <s.horvath@outlook.com.au>
Tested-by: Armin Wolf <W_Armin@gmx.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v5: Added Tested-by: tags

v4: Fix bug seen if the enable attribute was never read prior
    to a suspend/resume cycle.

v3: No change

v2: New patch

 drivers/hwmon/spd5118.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/drivers/hwmon/spd5118.c b/drivers/hwmon/spd5118.c
index d3fc0ae17743..d55c073ff5fd 100644
--- a/drivers/hwmon/spd5118.c
+++ b/drivers/hwmon/spd5118.c
@@ -20,6 +20,7 @@
 #include <linux/i2c.h>
 #include <linux/hwmon.h>
 #include <linux/module.h>
+#include <linux/pm.h>
 #include <linux/regmap.h>
 #include <linux/units.h>
 
@@ -432,6 +433,8 @@ static int spd5118_probe(struct i2c_client *client)
 	if (!spd5118_vendor_valid(bank, vendor))
 		return -ENODEV;
 
+	dev_set_drvdata(dev, regmap);
+
 	hwmon_dev = devm_hwmon_device_register_with_info(dev, "spd5118",
 							 regmap, &spd5118_chip_info,
 							 NULL);
@@ -449,6 +452,41 @@ static int spd5118_probe(struct i2c_client *client)
 	return 0;
 }
 
+static int spd5118_suspend(struct device *dev)
+{
+	struct regmap *regmap = dev_get_drvdata(dev);
+	u32 regval;
+	int err;
+
+	/*
+	 * Make sure the configuration register in the regmap cache is current
+	 * before bypassing it.
+	 */
+	err = regmap_read(regmap, SPD5118_REG_TEMP_CONFIG, &regval);
+	if (err < 0)
+		return err;
+
+	regcache_cache_bypass(regmap, true);
+	regmap_update_bits(regmap, SPD5118_REG_TEMP_CONFIG, SPD5118_TS_DISABLE,
+			   SPD5118_TS_DISABLE);
+	regcache_cache_bypass(regmap, false);
+
+	regcache_cache_only(regmap, true);
+	regcache_mark_dirty(regmap);
+
+	return 0;
+}
+
+static int spd5118_resume(struct device *dev)
+{
+	struct regmap *regmap = dev_get_drvdata(dev);
+
+	regcache_cache_only(regmap, false);
+	return regcache_sync(regmap);
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(spd5118_pm_ops, spd5118_suspend, spd5118_resume);
+
 static const struct i2c_device_id spd5118_id[] = {
 	{ "spd5118", 0 },
 	{ }
@@ -466,6 +504,7 @@ static struct i2c_driver spd5118_driver = {
 	.driver = {
 		.name	= "spd5118",
 		.of_match_table = spd5118_of_ids,
+		.pm = pm_sleep_ptr(&spd5118_pm_ops),
 	},
 	.probe		= spd5118_probe,
 	.id_table	= spd5118_id,
-- 
2.39.2

[PATCH v5 4/6] hwmon: (spd5118) Add support for reading SPD data

[Guenter Roeck]

Add support for reading SPD NVMEM data from SPD5118 (Jedec JESD300)
compliant memory modules. NVMEM write operation is not supported.

NVMEM support is optional. If CONFIG_NVMEM is disabled, the driver will
still instantiate but not provide NVMEM attribute files.

Tested-by: Armin Wolf <W_Armin@gmx.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v5: Added Tested-by: tag
    Dropped stray double empty line    

v4: Use NVMEM_DEVID_NONE instead of NVMEM_DEVID_AUTO
    Ignore nvmem registration failure if nvmem support is disabled

v3: New patch

 Documentation/hwmon/spd5118.rst |   8 ++
 drivers/hwmon/spd5118.c         | 146 +++++++++++++++++++++++++++++++-
 2 files changed, 150 insertions(+), 4 deletions(-)

diff --git a/Documentation/hwmon/spd5118.rst b/Documentation/hwmon/spd5118.rst
index a15d75aa2066..ef7338f46575 100644
--- a/Documentation/hwmon/spd5118.rst
+++ b/Documentation/hwmon/spd5118.rst
@@ -53,3 +53,11 @@ temp1_crit_alarm	Temperature critical alarm
 
 Alarm attributes are sticky until read and will be cleared afterwards
 unless the alarm condition still applies.
+
+
+SPD (Serial Presence Detect) support
+------------------------------------
+
+The driver also supports reading the SPD NVRAM on SPD5118 compatible chips.
+SPD data is available from the 'eeprom' binary attribute file attached to the
+chip's I2C device.
diff --git a/drivers/hwmon/spd5118.c b/drivers/hwmon/spd5118.c
index d55c073ff5fd..de6cf07f3007 100644
--- a/drivers/hwmon/spd5118.c
+++ b/drivers/hwmon/spd5118.c
@@ -20,6 +20,8 @@
 #include <linux/i2c.h>
 #include <linux/hwmon.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/nvmem-provider.h>
 #include <linux/pm.h>
 #include <linux/regmap.h>
 #include <linux/units.h>
@@ -53,12 +55,30 @@ static const unsigned short normal_i2c[] = {
 
 #define SPD5118_TS_DISABLE		BIT(0)	/* temperature sensor disable */
 
+#define SPD5118_LEGACY_MODE_ADDR	BIT(3)
+#define SPD5118_LEGACY_PAGE_MASK	GENMASK(2, 0)
+#define SPD5118_LEGACY_MODE_MASK	(SPD5118_LEGACY_MODE_ADDR | SPD5118_LEGACY_PAGE_MASK)
+
+#define SPD5118_NUM_PAGES		8
+#define SPD5118_PAGE_SIZE		128
+#define SPD5118_PAGE_SHIFT		7
+#define SPD5118_PAGE_MASK		GENMASK(6, 0)
+#define SPD5118_EEPROM_BASE		0x80
+#define SPD5118_EEPROM_SIZE		(SPD5118_PAGE_SIZE * SPD5118_NUM_PAGES)
+
 /* 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
 
+struct spd5118_data {
+	struct regmap *regmap;
+	struct mutex nvmem_lock;
+};
+
+/* hwmon */
+
 static int spd5118_temp_from_reg(u16 reg)
 {
 	int temp = sign_extend32(reg >> 2, 10);
@@ -360,9 +380,111 @@ static const struct hwmon_chip_info spd5118_chip_info = {
 	.info = spd5118_info,
 };
 
+/* nvmem */
+
+static int spd5118_nvmem_set_page(struct regmap *regmap, int page)
+{
+	unsigned int old_page;
+	int err;
+
+	err = regmap_read(regmap, SPD5118_REG_I2C_LEGACY_MODE, &old_page);
+	if (err)
+		return err;
+
+	if (page != (old_page & SPD5118_LEGACY_MODE_MASK)) {
+		/* Update page and explicitly select 1-byte addressing */
+		err = regmap_update_bits(regmap, SPD5118_REG_I2C_LEGACY_MODE,
+					 SPD5118_LEGACY_MODE_MASK, page);
+		if (err)
+			return err;
+
+		/* Selected new NVMEM page, drop cached data */
+		regcache_drop_region(regmap, SPD5118_EEPROM_BASE, 0xff);
+	}
+
+	return 0;
+}
+
+static ssize_t spd5118_nvmem_read_page(struct regmap *regmap, char *buf,
+				       unsigned int offset, size_t count)
+{
+	int err;
+
+	err = spd5118_nvmem_set_page(regmap, offset >> SPD5118_PAGE_SHIFT);
+	if (err)
+		return err;
+
+	offset &= SPD5118_PAGE_MASK;
+
+	/* Can't cross page boundaries */
+	if (offset + count > SPD5118_PAGE_SIZE)
+		count = SPD5118_PAGE_SIZE - offset;
+
+	err = regmap_bulk_read(regmap, SPD5118_EEPROM_BASE + offset, buf, count);
+	if (err)
+		return err;
+
+	return count;
+}
+
+static int spd5118_nvmem_read(void *priv, unsigned int off, void *val, size_t count)
+{
+	struct spd5118_data *data = priv;
+	char *buf = val;
+	int ret;
+
+	if (unlikely(!count))
+		return count;
+
+	if (off + count > SPD5118_EEPROM_SIZE)
+		return -EINVAL;
+
+	mutex_lock(&data->nvmem_lock);
+
+	while (count) {
+		ret = spd5118_nvmem_read_page(data->regmap, buf, off, count);
+		if (ret < 0) {
+			mutex_unlock(&data->nvmem_lock);
+			return ret;
+		}
+		buf += ret;
+		off += ret;
+		count -= ret;
+	}
+	mutex_unlock(&data->nvmem_lock);
+	return 0;
+}
+
+static int spd5118_nvmem_init(struct device *dev, struct spd5118_data *data)
+{
+	struct nvmem_config nvmem_config = {
+		.type = NVMEM_TYPE_EEPROM,
+		.name = dev_name(dev),
+		.id = NVMEM_DEVID_NONE,
+		.dev = dev,
+		.base_dev = dev,
+		.read_only = true,
+		.root_only = false,
+		.owner = THIS_MODULE,
+		.compat = true,
+		.reg_read = spd5118_nvmem_read,
+		.priv = data,
+		.stride = 1,
+		.word_size = 1,
+		.size = SPD5118_EEPROM_SIZE,
+	};
+	struct nvmem_device *nvmem;
+
+	nvmem = devm_nvmem_register(dev, &nvmem_config);
+	return PTR_ERR_OR_ZERO(nvmem);
+}
+
+/* regmap */
+
 static bool spd5118_writeable_reg(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
+	case SPD5118_REG_I2C_LEGACY_MODE:
 	case SPD5118_REG_TEMP_CLR:
 	case SPD5118_REG_TEMP_CONFIG:
 	case SPD5118_REG_TEMP_MAX:
@@ -396,7 +518,7 @@ static bool spd5118_volatile_reg(struct device *dev, unsigned int reg)
 static const struct regmap_config spd5118_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
-	.max_register = SPD5118_REG_TEMP_STATUS,
+	.max_register = 0xff,
 	.writeable_reg = spd5118_writeable_reg,
 	.volatile_reg = spd5118_volatile_reg,
 	.cache_type = REGCACHE_MAPLE,
@@ -406,10 +528,15 @@ static int spd5118_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
 	unsigned int regval, revision, vendor, bank;
+	struct spd5118_data *data;
 	struct device *hwmon_dev;
 	struct regmap *regmap;
 	int err;
 
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
 	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");
@@ -433,7 +560,16 @@ static int spd5118_probe(struct i2c_client *client)
 	if (!spd5118_vendor_valid(bank, vendor))
 		return -ENODEV;
 
-	dev_set_drvdata(dev, regmap);
+	data->regmap = regmap;
+	mutex_init(&data->nvmem_lock);
+	dev_set_drvdata(dev, data);
+
+	err = spd5118_nvmem_init(dev, data);
+	/* Ignore if NVMEM support is disabled */
+	if (err && err != -EOPNOTSUPP) {
+		dev_err_probe(dev, err, "failed to register nvmem\n");
+		return err;
+	}
 
 	hwmon_dev = devm_hwmon_device_register_with_info(dev, "spd5118",
 							 regmap, &spd5118_chip_info,
@@ -454,7 +590,8 @@ static int spd5118_probe(struct i2c_client *client)
 
 static int spd5118_suspend(struct device *dev)
 {
-	struct regmap *regmap = dev_get_drvdata(dev);
+	struct spd5118_data *data = dev_get_drvdata(dev);
+	struct regmap *regmap = data->regmap;
 	u32 regval;
 	int err;
 
@@ -479,7 +616,8 @@ static int spd5118_suspend(struct device *dev)
 
 static int spd5118_resume(struct device *dev)
 {
-	struct regmap *regmap = dev_get_drvdata(dev);
+	struct spd5118_data *data = dev_get_drvdata(dev);
+	struct regmap *regmap = data->regmap;
 
 	regcache_cache_only(regmap, false);
 	return regcache_sync(regmap);
-- 
2.39.2

[PATCH v5 5/6] i2c: smbus: Support DDR5 and LPDDR5 SPD EEPROMs

[Guenter Roeck]

Detect (LP)DDR5 memory and instantiate the SPD5118 driver automatically.

Suggested-by: Thomas Weißschuh <linux@weissschuh.net>
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Armin Wolf <W_Armin@gmx.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v5: Added reference to LPDDR5 to subject and description
    Updated comments associated with i2c_register_spd()
    to include support for (LP)DDR5

v4: New patch

 drivers/i2c/i2c-smbus.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
index 97f338b123b1..f809f0ef2004 100644
--- a/drivers/i2c/i2c-smbus.c
+++ b/drivers/i2c/i2c-smbus.c
@@ -308,7 +308,7 @@ EXPORT_SYMBOL_GPL(i2c_free_slave_host_notify_device);
  * target systems are the same.
  * Restrictions to automatic SPD instantiation:
  *  - Only works if all filled slots have the same memory type
- *  - Only works for DDR, DDR2, DDR3 and DDR4 for now
+ *  - Only works for (LP)DDR memory types up to DDR5
  *  - Only works on systems with 1 to 8 memory slots
  */
 #if IS_ENABLED(CONFIG_DMI)
@@ -382,6 +382,10 @@ void i2c_register_spd(struct i2c_adapter *adap)
 	case 0x1E:	/* LPDDR4 */
 		name = "ee1004";
 		break;
+	case 0x22:	/* DDR5 */
+	case 0x23:	/* LPDDR5 */
+		name = "spd5118";
+		break;
 	default:
 		dev_info(&adap->dev,
 			 "Memory type 0x%02x not supported yet, not instantiating SPD\n",
-- 
2.39.2

[PATCH v5 6/6] hwmon: (spd5118) Add configuration option for auto-detection

[Guenter Roeck]

With SPD5118 chip detection for the most part handled by the i2c-smbus
core using DMI information, the spd5118 driver no longer needs to
auto-detect spd5118 compliant chips.

Auto-detection by the driver is still needed on systems with no DMI support
or on systems with more than eight DIMMs and can not be removed entirely.
However, it affects boot time and introduces the risk of mis-identifying
chips. Add configuration option to be able to disable it on systems where
chip detection is handled outside the driver.

Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Armin Wolf <W_Armin@gmx.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v5: Added Tested-by: tag
    Replaced #ifdef with IS_ENABLED() and included address_list in
    conditional code

v4a:
    Do not auto-select SENSORS_SPD5118_DETECT if DMI is disabled
    Modify help text of SENSORS_SPD5118_DETECT
    Default SENSORS_SPD5118_DETECT to y if (!DMI || !X86)

v4: New patch

 drivers/hwmon/Kconfig   | 19 +++++++++++++++++++
 drivers/hwmon/spd5118.c |  4 ++--
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 7a84e7637b51..d5eced417fc3 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -2193,6 +2193,25 @@ config SENSORS_SPD5118
 	  This driver can also be built as a module. If so, the module
 	  will be called spd5118.
 
+config SENSORS_SPD5118_DETECT
+	bool "Enable detect function"
+	depends on SENSORS_SPD5118
+	default (!DMI || !X86)
+	help
+	  If enabled, the driver auto-detects if a chip in the SPD address
+	  range is compliant to the SPD51888 standard and auto-instantiates
+	  if that is the case. If disabled, SPD5118 compliant devices have
+	  to be instantiated by other means. On X86 systems with DMI support
+	  this will typically be done from DMI DDR detection code in the
+	  I2C SMBus subsystem. Devicetree based systems will instantiate
+	  attached devices if the DIMMs are listed in the devicetree file.
+
+	  Disabling the detect function will speed up boot time and reduce
+	  the risk of mis-detecting SPD5118 compliant devices. However, it
+	  may result in missed DIMMs under some circumstances.
+
+	  If unsure, say Y.
+
 config SENSORS_TC74
 	tristate "Microchip TC74"
 	depends on I2C
diff --git a/drivers/hwmon/spd5118.c b/drivers/hwmon/spd5118.c
index de6cf07f3007..ac94a6779360 100644
--- a/drivers/hwmon/spd5118.c
+++ b/drivers/hwmon/spd5118.c
@@ -646,8 +646,8 @@ static struct i2c_driver spd5118_driver = {
 	},
 	.probe		= spd5118_probe,
 	.id_table	= spd5118_id,
-	.detect		= spd5118_detect,
-	.address_list	= normal_i2c,
+	.detect		= IS_ENABLED(CONFIG_SENSORS_SPD5118_DETECT) ? spd5118_detect : NULL,
+	.address_list	= IS_ENABLED(CONFIG_SENSORS_SPD5118_DETECT) ? normal_i2c : NULL,
 };
 
 module_i2c_driver(spd5118_driver);
-- 
2.39.2

Re: [PATCH v5 0/6] hwmon: Add support for SPD5118 compliant chips

[Thomas Weißschuh]

On 2024-06-10 07:40:57+0000, Guenter Roeck wrote:
> Add support for SPD5118 (Jedec JESD300) compliant chips supporting
> a temperature sensor and SPD NVRAM. Such devices are typically found on
> DDR5 memory modules.

<snip>

> ----------------------------------------------------------------
> Guenter Roeck (6):
>       dt-bindings: trivial-devices: Add jedec,spd5118
>       hwmon: Add support for SPD5118 compliant temperature sensors
>       hwmon: (spd5118) Add suspend/resume support
>       hwmon: (spd5118) Add support for reading SPD data
>       i2c: smbus: Support DDR5 and LPDDR5 SPD EEPROMs
>       hwmon: (spd5118) Add configuration option for auto-detection
> 
>  .../devicetree/bindings/trivial-devices.yaml       |   2 +
>  Documentation/hwmon/index.rst                      |   1 +
>  Documentation/hwmon/spd5118.rst                    |  63 ++
>  drivers/hwmon/Kconfig                              |  31 +
>  drivers/hwmon/Makefile                             |   1 +
>  drivers/hwmon/spd5118.c                            | 658 +++++++++++++++++++++
>  drivers/i2c/i2c-smbus.c                            |   6 +-
>  7 files changed, 761 insertions(+), 1 deletion(-)
>  create mode 100644 Documentation/hwmon/spd5118.rst
>  create mode 100644 drivers/hwmon/spd5118.c

Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>

Re: [PATCH v5 0/6] hwmon: Add support for SPD5118 compliant chips

[Guenter Roeck]

On 6/10/24 08:27, Thomas Weißschuh wrote:
> On 2024-06-10 07:40:57+0000, Guenter Roeck wrote:
>> Add support for SPD5118 (Jedec JESD300) compliant chips supporting
>> a temperature sensor and SPD NVRAM. Such devices are typically found on
>> DDR5 memory modules.
> 
> <snip>
> 
>> ----------------------------------------------------------------
>> Guenter Roeck (6):
>>        dt-bindings: trivial-devices: Add jedec,spd5118
>>        hwmon: Add support for SPD5118 compliant temperature sensors
>>        hwmon: (spd5118) Add suspend/resume support
>>        hwmon: (spd5118) Add support for reading SPD data
>>        i2c: smbus: Support DDR5 and LPDDR5 SPD EEPROMs
>>        hwmon: (spd5118) Add configuration option for auto-detection
>>
>>   .../devicetree/bindings/trivial-devices.yaml       |   2 +
>>   Documentation/hwmon/index.rst                      |   1 +
>>   Documentation/hwmon/spd5118.rst                    |  63 ++
>>   drivers/hwmon/Kconfig                              |  31 +
>>   drivers/hwmon/Makefile                             |   1 +
>>   drivers/hwmon/spd5118.c                            | 658 +++++++++++++++++++++
>>   drivers/i2c/i2c-smbus.c                            |   6 +-
>>   7 files changed, 761 insertions(+), 1 deletion(-)
>>   create mode 100644 Documentation/hwmon/spd5118.rst
>>   create mode 100644 drivers/hwmon/spd5118.c
> 
> Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>

Thanks!

Guenter