* [PATCH v6 2/2] hwmon: temperature: add support for EMC1812
2026-02-12 9:54 [PATCH v6 0/2] Add support for Microchip EMC1812 Marius Cristea
2026-02-12 9:54 ` [PATCH v6 1/2] dt-bindings: hwmon: temperature: add support for EMC1812 Marius Cristea
@ 2026-02-12 9:54 ` Marius Cristea
1 sibling, 0 replies; 4+ messages in thread
From: Marius Cristea @ 2026-02-12 9:54 UTC (permalink / raw)
To: Guenter Roeck, Rob Herring, Krzysztof Kozlowski, Conor Dooley,
Jonathan Corbet
Cc: linux-hwmon, devicetree, linux-kernel, linux-doc, Marius Cristea
This is the hwmon driver for Microchip EMC1812/13/14/15/33
Multichannel Low-Voltage Remote Diode Sensor Family.
EMC1812 has one external remote temperature monitoring channel.
EMC1813 has two external remote temperature monitoring channels.
EMC1814 has three external remote temperature monitoring channels and
channels 2 and 3 support anti parallel diode.
EMC1815 has four external remote temperature monitoring channels and
channels 1/2 and 3/4 support anti parallel diode.
EMC1833 has two external remote temperature monitoring channels and
channels 1 and 2 support anti parallel diode.
Signed-off-by: Marius Cristea <marius.cristea@microchip.com>
---
Documentation/hwmon/emc1812.rst | 68 +++
Documentation/hwmon/index.rst | 1 +
MAINTAINERS | 2 +
drivers/hwmon/Kconfig | 11 +
drivers/hwmon/Makefile | 1 +
drivers/hwmon/emc1812.c | 942 ++++++++++++++++++++++++++++++++++++++++
6 files changed, 1025 insertions(+)
diff --git a/Documentation/hwmon/emc1812.rst b/Documentation/hwmon/emc1812.rst
new file mode 100644
index 0000000000000000000000000000000000000000..0b5c7e6a53ded898cd2e146ff8e7bb1fc9e03314
--- /dev/null
+++ b/Documentation/hwmon/emc1812.rst
@@ -0,0 +1,68 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver emc1812
+=====================
+
+Supported chips:
+
+ * Microchip EMC1812, EMC1813, EMC1814, EMC1815, EMC1833
+
+ Addresses scanned: I2C 0x1c, 0x3c, 0x4c, 0x4d, 0x5c, 0x6c, 0x7c
+
+ Prefix: 'emc1812'
+
+ Datasheets:
+
+ - https://ww1.microchip.com/downloads/aemDocuments/documents/MSLD/ProductDocuments/DataSheets/EMC1812-3-4-5-33-Data-Sheet-DS20005751.pdf
+
+Author:
+ Marius Cristea <marius.cristea@microchip.com>
+
+
+Description
+-----------
+
+The Microchip EMC181x/33 chips contain up to 4 remote temperature sensors
+and one internal.
+- The EMC1812 is a single channel remote temperature sensor.
+- The EMC1813 and EMC1833 is a dual channel remote temperature sensor. The
+remote channels for this selection of devices can support substrate diodes,
+discrete diode-connected transistors or CPU/GPU thermal diodes.
+- The EMC1814 is a three channel remote temperature sensor that supports
+Anti-Parallel Diode (APD) only on one channel. For the channel that does not
+support APD functionality, substrate diodes, discrete diode-connected
+transistors or CPU/GPU thermal diodes are supported. For the channel that
+supports APD, only discrete diode-connected transistors may be implemented.
+However, if APD is disabled on the EMC1814, then the channel that supports
+APD will be functional with substrate diodes, discrete diode-connected
+transistors and CPU/GPU thermal diodes.
+- The EMC1815 is a four channel remote temperature sensor. The EMC1815 and
+EMC1833 support APD on all channels. When APD is enabled, the channels support
+only diode-connected transistors. If APD is disabled, then the channels will
+support substrate transistors, discrete diode-connected transistors and
+CPU/GPU thermal diodes.
+
+Note: Disabling APD functionality to implement substrate diodes on devices
+that support APD eliminates the benefit of APD (two diodes on one channel).
+
+The chips implement three limits for each sensor: low (tempX_min), high
+(tempX_max) and critical (tempX_crit). The chips also implement an
+hysteresis mechanism which applies to all limits. The relative difference
+is stored in a single register on the chip, which means that the relative
+difference between the limit and its hysteresis is always the same for
+all three limits.
+
+This implementation detail implies the following:
+
+* When setting a limit, its hysteresis will automatically follow, the
+ difference staying unchanged. For example, if the old critical limit was
+ 80 degrees C, and the hysteresis was 75 degrees C, and you change the
+ critical limit to 90 degrees C, then the hysteresis will automatically
+ change to 85 degrees C.
+* The hysteresis values can't be set independently. We decided to make
+ only tempX_crit_hyst writable, while all other hysteresis attributes
+ are read-only. Setting tempX_crit_hyst writes the difference between
+ tempX_crit_hyst and tempX_crit into the chip, and the same relative
+ hysteresis applies automatically to all other limits.
+* The limits should be set before the hysteresis. At power up the device
+ starts with a 10 degree written into hysteresis register.
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 51a5bdf75b08656ee6499c6b5c50a51fc4d7c210..a03e97f9a97f4d3edf7bcd1e8d1b73a21d5f0ab5 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -69,6 +69,7 @@ Hardware Monitoring Kernel Drivers
ds1621
ds620
emc1403
+ emc1812
emc2103
emc2305
emc6w201
diff --git a/MAINTAINERS b/MAINTAINERS
index 85c236df781e47c78deeb7ef4d80bc94bba604c4..fcb712549ea679d49fde8c97840af9528b52d52b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16651,6 +16651,8 @@ M: Marius Cristea <marius.cristea@microchip.com>
L: linux-hwmon@vger.kernel.org
S: Supported
F: Documentation/devicetree/bindings/hwmon/microchip,emc1812.yaml
+F: Documentation/hwmon/emc1812.rst
+F: drivers/hwmon/emc1812.c
MICROCHIP I2C DRIVER
M: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 2760feb9f83b5d3b990b27acff572e587b373e9d..3b53572fd8bfbd752c2235ca429c4f74b1db3095 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -2042,6 +2042,17 @@ config SENSORS_EMC1403
Threshold values can be configured using sysfs.
Data from the different diodes are accessible via sysfs.
+config SENSORS_EMC1812
+ tristate "Microchip Technology EMC1812 driver"
+ depends on I2C
+ select REGMAP_I2C
+ help
+ If you say yes here to build support for Microchip Technology's
+ EMC181X/33 Multichannel Low-Voltage Remote Diode Sensor Family.
+
+ This driver can also be built as a module. If so, the module
+ will be called emc1812.
+
config SENSORS_EMC2103
tristate "SMSC EMC2103"
depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 73b2abdcc6dd9cfae4c84b350febc5d8c191e385..e93e4051e99db698dbaae97ac4841e6d810ee8c4 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -73,6 +73,7 @@ obj-$(CONFIG_SENSORS_DRIVETEMP) += drivetemp.o
obj-$(CONFIG_SENSORS_DS620) += ds620.o
obj-$(CONFIG_SENSORS_DS1621) += ds1621.o
obj-$(CONFIG_SENSORS_EMC1403) += emc1403.o
+obj-$(CONFIG_SENSORS_EMC1812) += emc1812.o
obj-$(CONFIG_SENSORS_EMC2103) += emc2103.o
obj-$(CONFIG_SENSORS_EMC2305) += emc2305.o
obj-$(CONFIG_SENSORS_EMC6W201) += emc6w201.o
diff --git a/drivers/hwmon/emc1812.c b/drivers/hwmon/emc1812.c
new file mode 100644
index 0000000000000000000000000000000000000000..bce36c3a8f040e88ef581b644317de74934140a4
--- /dev/null
+++ b/drivers/hwmon/emc1812.c
@@ -0,0 +1,942 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * HWMON driver for Microchip EMC1812/13/14/15/33 Multichannel high-accuracy
+ * 2-wire low-voltage remote diode temperature monitor family.
+ *
+ * Copyright (C) 2026 Microchip Technology Inc. and its subsidiaries
+ *
+ * Author: Marius Cristea <marius.cristea@microchip.com>
+ *
+ * Datasheet can be found here:
+ * https://ww1.microchip.com/downloads/aemDocuments/documents/MSLD/ProductDocuments/DataSheets/EMC1812-3-4-5-33-Data-Sheet-DS20005751.pdf
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/math64.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/string.h>
+#include <linux/units.h>
+#include <linux/util_macros.h>
+
+/* EMC1812 Registers Addresses */
+#define EMC1812_STATUS_ADDR 0x02
+#define EMC1812_CONFIG_LO_ADDR 0x03
+
+#define EMC1812_CFG_ADDR 0x09
+#define EMC1812_CONV_ADDR 0x0A
+#define EMC1812_INT_DIODE_HIGH_LIMIT_ADDR 0x0B
+#define EMC1812_INT_DIODE_LOW_LIMIT_ADDR 0x0C
+#define EMC1812_EXT1_HIGH_LIMIT_HIGH_BYTE_ADDR 0x0D
+#define EMC1812_EXT1_LOW_LIMIT_HIGH_BYTE_ADDR 0x0E
+#define EMC1812_ONE_SHOT_ADDR 0x0F
+
+#define EMC1812_EXT1_HIGH_LIMIT_LOW_BYTE_ADDR 0x13
+#define EMC1812_EXT1_LOW_LIMIT_LOW_BYTE_ADDR 0x14
+#define EMC1812_EXT2_HIGH_LIMIT_HIGH_BYTE_ADDR 0x15
+#define EMC1812_EXT2_LOW_LIMIT_HIGH_BYTE_ADDR 0x16
+#define EMC1812_EXT2_HIGH_LIMIT_LOW_BYTE_ADDR 0x17
+#define EMC1812_EXT2_LOW_LIMIT_LOW_BYTE_ADDR 0x18
+#define EMC1812_EXT1_THERM_LIMIT_ADDR 0x19
+#define EMC1812_EXT2_THERM_LIMIT_ADDR 0x1A
+#define EMC1812_EXT_DIODE_FAULT_STATUS_ADDR 0x1B
+
+#define EMC1812_DIODE_FAULT_MASK_ADDR 0x1F
+#define EMC1812_INT_DIODE_THERM_LIMIT_ADDR 0x20
+#define EMC1812_THRM_HYS_ADDR 0x21
+#define EMC1812_CONSEC_ALERT_ADDR 0x22
+
+#define EMC1812_EXT1_BETA_CONFIG_ADDR 0x25
+#define EMC1812_EXT2_BETA_CONFIG_ADDR 0x26
+#define EMC1812_EXT1_IDEALITY_FACTOR_ADDR 0x27
+#define EMC1812_EXT2_IDEALITY_FACTOR_ADDR 0x28
+
+#define EMC1812_EXT3_HIGH_LIMIT_HIGH_BYTE_ADDR 0x2C
+#define EMC1812_EXT3_LOW_LIMIT_HIGH_BYTE_ADDR 0x2D
+#define EMC1812_EXT3_HIGH_LIMIT_LOW_BYTE_ADDR 0x2E
+#define EMC1812_EXT3_LOW_LIMIT_LOW_BYTE_ADDR 0x2F
+#define EMC1812_EXT3_THERM_LIMIT_ADDR 0x30
+#define EMC1812_EXT3_IDEALITY_FACTOR_ADDR 0x31
+
+#define EMC1812_EXT4_HIGH_LIMIT_HIGH_BYTE_ADDR 0x34
+#define EMC1812_EXT4_LOW_LIMIT_HIGH_BYTE_ADDR 0x35
+#define EMC1812_EXT4_HIGH_LIMIT_LOW_BYTE_ADDR 0x36
+#define EMC1812_EXT4_LOW_LIMIT_LOW_BYTE_ADDR 0x37
+#define EMC1812_EXT4_THERM_LIMIT_ADDR 0x38
+#define EMC1812_EXT4_IDEALITY_FACTOR_ADDR 0x39
+#define EMC1812_HIGH_LIMIT_STATUS_ADDR 0x3A
+#define EMC1812_LOW_LIMIT_STATUS_ADDR 0x3B
+#define EMC1812_THERM_LIMIT_STATUS_ADDR 0x3C
+#define EMC1812_ROC_GAIN_ADDR 0x3D
+#define EMC1812_ROC_CONFIG_ADDR 0x3E
+#define EMC1812_ROC_STATUS_ADDR 0x3F
+#define EMC1812_R1_RESH_ADDR 0x40
+#define EMC1812_R1_LIMH_ADDR 0x41
+#define EMC1812_R1_LIML_ADDR 0x42
+#define EMC1812_R1_SMPL_ADDR 0x43
+#define EMC1812_R2_RESH_ADDR 0x44
+#define EMC1812_R2_3_RESL_ADDR 0x45
+#define EMC1812_R2_LIMH_ADDR 0x46
+#define EMC1812_R2_LIML_ADDR 0x47
+#define EMC1812_R2_SMPL_ADDR 0x48
+#define EMC1812_PER_MAXTH_1_ADDR 0x49
+#define EMC1812_PER_MAXT1L_ADDR 0x4A
+#define EMC1812_PER_MAXTH_2_ADDR 0x4B
+#define EMC1812_PER_MAXT2_3L_ADDR 0x4C
+#define EMC1812_GBL_MAXT1H_ADDR 0x4D
+#define EMC1812_GBL_MAXT1L_ADDR 0x4E
+#define EMC1812_GBL_MAXT2H_ADDR 0x4F
+#define EMC1812_GBL_MAXT2L_ADDR 0x50
+#define EMC1812_FILTER_SEL_ADDR 0x51
+
+#define EMC1812_INT_HIGH_BYTE_ADDR 0x60
+#define EMC1812_INT_LOW_BYTE_ADDR 0x61
+#define EMC1812_EXT1_HIGH_BYTE_ADDR 0x62
+#define EMC1812_EXT1_LOW_BYTE_ADDR 0x63
+#define EMC1812_EXT2_HIGH_BYTE_ADDR 0x64
+#define EMC1812_EXT2_LOW_BYTE_ADDR 0x65
+#define EMC1812_EXT3_HIGH_BYTE_ADDR 0x66
+#define EMC1812_EXT3_LOW_BYTE_ADDR 0x67
+#define EMC1812_EXT4_HIGH_BYTE_ADDR 0x68
+#define EMC1812_EXT4_LOW_BYTE_ADDR 0x69
+#define EMC1812_HOTTEST_DIODE_HIGH_BYTE_ADDR 0x6A
+#define EMC1812_HOTTEST_DIODE_LOW_BYTE_ADDR 0x6B
+#define EMC1812_HOTTEST_STATUS_ADDR 0x6C
+#define EMC1812_HOTTEST_CFG_ADDR 0x6D
+
+#define EMC1812_PRODUCT_ID_ADDR 0xFD
+#define EMC1812_MANUFACTURER_ID_ADDR 0xFE
+#define EMC1812_REVISION_ADDR 0xFF
+
+/* EMC1812 Config Bits */
+#define EMC1812_CFG_MSKAL BIT(7)
+#define EMC1812_CFG_RS BIT(6)
+#define EMC1812_CFG_ATTHM BIT(5)
+#define EMC1812_CFG_RECD12 BIT(4)
+#define EMC1812_CFG_RECD34 BIT(3)
+#define EMC1812_CFG_RANGE BIT(2)
+#define EMC1812_CFG_DA_ENA BIT(1)
+#define EMC1812_CFG_APDD BIT(0)
+
+/* EMC1812 Status Bits */
+#define EMC1812_STATUS_ROCF BIT(7)
+#define EMC1812_STATUS_HOTCHG BIT(6)
+#define EMC1812_STATUS_BUSY BIT(5)
+#define EMC1812_STATUS_HIGH BIT(4)
+#define EMC1812_STATUS_LOW BIT(3)
+#define EMC1812_STATUS_FAULT BIT(2)
+#define EMC1812_STATUS_ETHRM BIT(1)
+#define EMC1812_STATUS_ITHRM BIT(0)
+
+#define EMC1812_BETA_LOCK_VAL 0x0F
+
+#define EMC1812_TEMP_CH_ADDR(index) (EMC1812_INT_HIGH_BYTE_ADDR + 2 * (index))
+
+#define EMC1812_FILTER_MASK_LEN 2
+
+#define EMC1812_PID 0x81
+#define EMC1813_PID 0x87
+#define EMC1814_PID 0x84
+#define EMC1815_PID 0x85
+#define EMC1833_PID 0x83
+
+/* The maximum number of channels a member of the family can have */
+#define EMC1812_MAX_NUM_CHANNELS 5
+#define EMC1812_TEMP_OFFSET 64
+
+#define EMC1812_DEFAULT_IDEALITY_FACTOR 0x12
+
+#define EMC1812_TEMP_MASK (HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX | \
+ HWMON_T_CRIT | HWMON_T_MAX_HYST | HWMON_T_CRIT_HYST | \
+ HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM | \
+ HWMON_T_CRIT_ALARM | HWMON_T_LABEL)
+
+static const struct hwmon_channel_info * const emc1812_info[] = {
+ HWMON_CHANNEL_INFO(chip, HWMON_C_UPDATE_INTERVAL),
+ HWMON_CHANNEL_INFO(temp,
+ EMC1812_TEMP_MASK,
+ EMC1812_TEMP_MASK | HWMON_T_FAULT,
+ EMC1812_TEMP_MASK | HWMON_T_FAULT,
+ EMC1812_TEMP_MASK | HWMON_T_FAULT,
+ EMC1812_TEMP_MASK | HWMON_T_FAULT
+ ),
+ NULL
+};
+
+/**
+ * struct emc1812_features - features of a emc1812 instance
+ * @name: chip's name
+ * @phys_channels: number of physical channels supported by the chip
+ */
+struct emc1812_features {
+ const char *name;
+ u8 phys_channels;
+};
+
+static const struct emc1812_features emc1833_chip_config = {
+ .name = "emc1833",
+ .phys_channels = 3,
+};
+
+static const struct emc1812_features emc1812_chip_config = {
+ .name = "emc1812",
+ .phys_channels = 2,
+};
+
+static const struct emc1812_features emc1813_chip_config = {
+ .name = "emc1813",
+ .phys_channels = 3,
+};
+
+static const struct emc1812_features emc1814_chip_config = {
+ .name = "emc1814",
+ .phys_channels = 4,
+};
+
+static const struct emc1812_features emc1815_chip_config = {
+ .name = "emc1815",
+ .phys_channels = 5,
+};
+
+enum emc1812_limit_type {temp_min, temp_max};
+
+static u8 emc1812_temp_map[] = {
+ [hwmon_temp_min] = temp_min,
+ [hwmon_temp_max] = temp_max,
+};
+
+static u8 emc1812_temp_crit_regs[] = {
+ [0] = EMC1812_INT_DIODE_THERM_LIMIT_ADDR,
+ [1] = EMC1812_EXT1_THERM_LIMIT_ADDR,
+ [2] = EMC1812_EXT2_THERM_LIMIT_ADDR,
+ [3] = EMC1812_EXT3_THERM_LIMIT_ADDR,
+ [4] = EMC1812_EXT4_THERM_LIMIT_ADDR,
+};
+
+static u8 emc1812_limit_regs[][2] = {
+ [0] = {
+ [temp_min] = EMC1812_INT_DIODE_LOW_LIMIT_ADDR,
+ [temp_max] = EMC1812_INT_DIODE_HIGH_LIMIT_ADDR,
+ },
+ [1] = {
+ [temp_min] = EMC1812_EXT1_LOW_LIMIT_HIGH_BYTE_ADDR,
+ [temp_max] = EMC1812_EXT1_HIGH_LIMIT_HIGH_BYTE_ADDR,
+ },
+ [2] = {
+ [temp_min] = EMC1812_EXT2_LOW_LIMIT_HIGH_BYTE_ADDR,
+ [temp_max] = EMC1812_EXT2_HIGH_LIMIT_HIGH_BYTE_ADDR,
+ },
+ [3] = {
+ [temp_min] = EMC1812_EXT3_LOW_LIMIT_HIGH_BYTE_ADDR,
+ [temp_max] = EMC1812_EXT3_HIGH_LIMIT_HIGH_BYTE_ADDR,
+ },
+ [4] = {
+ [temp_min] = EMC1812_EXT4_LOW_LIMIT_HIGH_BYTE_ADDR,
+ [temp_max] = EMC1812_EXT4_HIGH_LIMIT_HIGH_BYTE_ADDR,
+ },
+};
+
+static u8 emc1812_limit_regs_low[][3] = {
+ [0] = {
+ [temp_min] = 0xff,
+ [temp_max] = 0xff,
+ },
+ [1] = {
+ [temp_min] = EMC1812_EXT1_LOW_LIMIT_LOW_BYTE_ADDR,
+ [temp_max] = EMC1812_EXT1_HIGH_LIMIT_LOW_BYTE_ADDR,
+ },
+ [2] = {
+ [temp_min] = EMC1812_EXT2_LOW_LIMIT_LOW_BYTE_ADDR,
+ [temp_max] = EMC1812_EXT2_HIGH_LIMIT_LOW_BYTE_ADDR,
+ },
+ [3] = {
+ [temp_min] = EMC1812_EXT3_LOW_LIMIT_LOW_BYTE_ADDR,
+ [temp_max] = EMC1812_EXT3_HIGH_LIMIT_LOW_BYTE_ADDR,
+ },
+ [4] = {
+ [temp_min] = EMC1812_EXT4_LOW_LIMIT_LOW_BYTE_ADDR,
+ [temp_max] = EMC1812_EXT4_HIGH_LIMIT_LOW_BYTE_ADDR,
+ },
+};
+
+/* Lookup table for temperature conversion times in msec */
+static const u16 emc1812_conv_time[] = {
+ 16000, 8000, 4000, 2000, 1000, 500, 250, 125, 62, 31, 16
+};
+
+/**
+ * struct emc1812_data - information about chip parameters
+ * @labels: labels of the channels
+ * @active_ch_mask: active channels
+ * @chip: pointer to structure holding chip features
+ * @regmap: device register map
+ * @recd34_en: state of Resistance Error Correction (REC) on channels 3 and 4
+ * @recd12_en: state of Resistance Error Correction (REC) on channels 1 and 2
+ * @apdd_en: state of anti-parallel diode mode
+ */
+struct emc1812_data {
+ const char *labels[EMC1812_MAX_NUM_CHANNELS];
+ unsigned long active_ch_mask;
+ const struct emc1812_features *chip;
+ struct regmap *regmap;
+ bool recd34_en;
+ bool recd12_en;
+ bool apdd_en;
+};
+
+/* emc1812 regmap configuration */
+static const struct regmap_range emc1812_regmap_writable_ranges[] = {
+ regmap_reg_range(EMC1812_CFG_ADDR, EMC1812_ONE_SHOT_ADDR),
+ regmap_reg_range(EMC1812_EXT1_HIGH_LIMIT_LOW_BYTE_ADDR,
+ EMC1812_EXT_DIODE_FAULT_STATUS_ADDR),
+ regmap_reg_range(EMC1812_DIODE_FAULT_MASK_ADDR, EMC1812_CONSEC_ALERT_ADDR),
+ regmap_reg_range(EMC1812_EXT1_BETA_CONFIG_ADDR, EMC1812_FILTER_SEL_ADDR),
+ regmap_reg_range(EMC1812_HOTTEST_STATUS_ADDR, EMC1812_HOTTEST_CFG_ADDR),
+};
+
+static const struct regmap_access_table emc1812_regmap_wr_table = {
+ .yes_ranges = emc1812_regmap_writable_ranges,
+ .n_yes_ranges = ARRAY_SIZE(emc1812_regmap_writable_ranges),
+};
+
+static const struct regmap_range emc1812_regmap_rd_ranges[] = {
+ regmap_reg_range(EMC1812_STATUS_ADDR, EMC1812_CONFIG_LO_ADDR),
+ regmap_reg_range(EMC1812_CFG_ADDR, EMC1812_ONE_SHOT_ADDR),
+ regmap_reg_range(EMC1812_EXT1_HIGH_LIMIT_LOW_BYTE_ADDR,
+ EMC1812_EXT_DIODE_FAULT_STATUS_ADDR),
+ regmap_reg_range(EMC1812_DIODE_FAULT_MASK_ADDR, EMC1812_CONSEC_ALERT_ADDR),
+ regmap_reg_range(EMC1812_EXT1_BETA_CONFIG_ADDR, EMC1812_FILTER_SEL_ADDR),
+ regmap_reg_range(EMC1812_INT_HIGH_BYTE_ADDR, EMC1812_HOTTEST_CFG_ADDR),
+ regmap_reg_range(EMC1812_PRODUCT_ID_ADDR, EMC1812_REVISION_ADDR),
+};
+
+static const struct regmap_access_table emc1812_regmap_rd_table = {
+ .yes_ranges = emc1812_regmap_rd_ranges,
+ .n_yes_ranges = ARRAY_SIZE(emc1812_regmap_rd_ranges),
+};
+
+static bool emc1812_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+ switch (reg) {
+ case EMC1812_STATUS_ADDR:
+ case EMC1812_EXT_DIODE_FAULT_STATUS_ADDR:
+ case EMC1812_DIODE_FAULT_MASK_ADDR:
+ case EMC1812_EXT1_BETA_CONFIG_ADDR:
+ case EMC1812_EXT2_BETA_CONFIG_ADDR:
+ case EMC1812_HIGH_LIMIT_STATUS_ADDR:
+ case EMC1812_LOW_LIMIT_STATUS_ADDR:
+ case EMC1812_THERM_LIMIT_STATUS_ADDR:
+ case EMC1812_ROC_STATUS_ADDR:
+ case EMC1812_PER_MAXTH_1_ADDR:
+ case EMC1812_PER_MAXT1L_ADDR:
+ case EMC1812_PER_MAXTH_2_ADDR:
+ case EMC1812_PER_MAXT2_3L_ADDR:
+ case EMC1812_GBL_MAXT1H_ADDR:
+ case EMC1812_GBL_MAXT1L_ADDR:
+ case EMC1812_GBL_MAXT2H_ADDR:
+ case EMC1812_GBL_MAXT2L_ADDR:
+ case EMC1812_INT_HIGH_BYTE_ADDR:
+ case EMC1812_INT_LOW_BYTE_ADDR:
+ case EMC1812_EXT1_HIGH_BYTE_ADDR:
+ case EMC1812_EXT1_LOW_BYTE_ADDR:
+ case EMC1812_EXT2_HIGH_BYTE_ADDR:
+ case EMC1812_EXT2_LOW_BYTE_ADDR:
+ case EMC1812_EXT3_HIGH_BYTE_ADDR:
+ case EMC1812_EXT3_LOW_BYTE_ADDR:
+ case EMC1812_EXT4_HIGH_BYTE_ADDR:
+ case EMC1812_EXT4_LOW_BYTE_ADDR:
+ case EMC1812_HOTTEST_DIODE_HIGH_BYTE_ADDR:
+ case EMC1812_HOTTEST_DIODE_LOW_BYTE_ADDR:
+ case EMC1812_HOTTEST_STATUS_ADDR:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static const struct regmap_config emc1812_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .rd_table = &emc1812_regmap_rd_table,
+ .wr_table = &emc1812_regmap_wr_table,
+ .volatile_reg = emc1812_is_volatile_reg,
+ .max_register = EMC1812_REVISION_ADDR,
+ .cache_type = REGCACHE_MAPLE,
+};
+
+static umode_t emc1812_is_visible(const void *_data, enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ const struct emc1812_data *data = _data;
+
+ switch (type) {
+ case hwmon_temp:
+ /* Don't show channels which are not described into the device tree */
+ if (!(data->active_ch_mask & BIT(channel)))
+ return 0;
+
+ /* Don't show channels which are not physically connected */
+ if (channel >= data->chip->phys_channels)
+ return 0;
+
+ switch (attr) {
+ case hwmon_temp_min:
+ case hwmon_temp_max:
+ case hwmon_temp_crit:
+ case hwmon_temp_crit_hyst:
+ return 0644;
+ case hwmon_temp_crit_alarm:
+ case hwmon_temp_input:
+ case hwmon_temp_fault:
+ case hwmon_temp_max_alarm:
+ case hwmon_temp_max_hyst:
+ case hwmon_temp_min_alarm:
+ return 0444;
+ case hwmon_temp_label:
+ if (data->labels[channel])
+ return 0444;
+ return 0;
+ default:
+ return 0;
+ }
+ case hwmon_chip:
+ switch (attr) {
+ case hwmon_chip_update_interval:
+ return 0644;
+ default:
+ return 0;
+ }
+ default:
+ return 0;
+ }
+};
+
+static int emc1812_get_temp(struct emc1812_data *data, int channel, long *val)
+{
+ __be16 tmp_be16;
+ int ret;
+
+ ret = regmap_bulk_read(data->regmap, EMC1812_TEMP_CH_ADDR(channel),
+ &tmp_be16, sizeof(tmp_be16));
+ if (ret)
+ return ret;
+
+ /* Range is always -64 to 191.875°C */
+ *val = ((be16_to_cpu(tmp_be16) >> 5) - (EMC1812_TEMP_OFFSET << 3)) * 125;
+
+ return 0;
+}
+
+static int emc1812_get_crit_limit_temp(struct emc1812_data *data, int channel, long *val)
+{
+ unsigned int tmp;
+ int ret;
+
+ /* Critical register is 8bits long and keeps only integer part of temperature */
+ ret = regmap_read(data->regmap, emc1812_temp_crit_regs[channel], &tmp);
+ if (ret)
+ return ret;
+
+ *val = tmp;
+ /* Range is always -64 to 191°C */
+ *val = (*val - EMC1812_TEMP_OFFSET) * 1000;
+
+ return 0;
+}
+
+static int emc1812_get_limit_temp(struct emc1812_data *data, int ch,
+ enum emc1812_limit_type type, long *val)
+{
+ unsigned int regvalh;
+ unsigned int regvall = 0;
+ int ret;
+
+ ret = regmap_read(data->regmap, emc1812_limit_regs[ch][type], ®valh);
+ if (ret < 0)
+ return ret;
+
+ if (ch) {
+ ret = regmap_read(data->regmap, emc1812_limit_regs_low[ch][type], ®vall);
+ if (ret < 0)
+ return ret;
+ }
+
+ /* Range is always -64 to 191.875°C */
+ *val = ((regvalh << 3) | (regvall >> 5));
+ *val = (*val - (EMC1812_TEMP_OFFSET << 3)) * 125;
+
+ return 0;
+}
+
+static int emc1812_read_reg(struct device *dev, struct emc1812_data *data, u32 attr,
+ int channel, long *val)
+{
+ int hyst, ret;
+
+ switch (attr) {
+ case hwmon_temp_min:
+ case hwmon_temp_max:
+ return emc1812_get_limit_temp(data, channel, emc1812_temp_map[attr], val);
+ case hwmon_temp_crit:
+ return emc1812_get_crit_limit_temp(data, channel, val);
+ case hwmon_temp_input:
+ return emc1812_get_temp(data, channel, val);
+ case hwmon_temp_max_hyst:
+ ret = emc1812_get_limit_temp(data, channel, temp_max, val);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_read(data->regmap, EMC1812_THRM_HYS_ADDR, &hyst);
+ if (ret < 0)
+ return ret;
+
+ *val -= hyst * 1000;
+
+ return 0;
+ case hwmon_temp_crit_hyst:
+ ret = emc1812_get_crit_limit_temp(data, channel, val);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_read(data->regmap, EMC1812_THRM_HYS_ADDR, &hyst);
+ if (ret < 0)
+ return ret;
+
+ *val -= hyst * 1000;
+
+ return 0;
+ case hwmon_temp_min_alarm:
+ *val = regmap_test_bits(data->regmap, EMC1812_LOW_LIMIT_STATUS_ADDR,
+ BIT(channel));
+ if (*val < 0)
+ return *val;
+
+ return 0;
+ case hwmon_temp_max_alarm:
+ *val = regmap_test_bits(data->regmap, EMC1812_HIGH_LIMIT_STATUS_ADDR,
+ BIT(channel));
+ if (*val < 0)
+ return *val;
+
+ return 0;
+ case hwmon_temp_crit_alarm:
+ *val = regmap_test_bits(data->regmap, EMC1812_THERM_LIMIT_STATUS_ADDR,
+ BIT(channel));
+ if (*val < 0)
+ return *val;
+
+ return 0;
+ case hwmon_temp_fault:
+ *val = regmap_test_bits(data->regmap, EMC1812_EXT_DIODE_FAULT_STATUS_ADDR,
+ BIT(channel));
+ if (*val < 0)
+ return *val;
+
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int emc1812_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
+ int channel, long *val)
+{
+ struct emc1812_data *data = dev_get_drvdata(dev);
+ unsigned int convrate;
+ int ret;
+
+ switch (type) {
+ case hwmon_temp:
+ return emc1812_read_reg(dev, data, attr, channel, val);
+ case hwmon_chip:
+ switch (attr) {
+ case hwmon_chip_update_interval:
+ ret = regmap_read(data->regmap, EMC1812_CONV_ADDR, &convrate);
+ if (ret < 0)
+ return ret;
+
+ if (convrate > 10)
+ convrate = 4;
+
+ *val = DIV_ROUND_CLOSEST(16000, 1 << convrate);
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int emc1812_read_string(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, const char **str)
+{
+ struct emc1812_data *data = dev_get_drvdata(dev);
+
+ if (channel >= data->chip->phys_channels)
+ return 0;
+
+ switch (type) {
+ case hwmon_temp:
+ switch (attr) {
+ case hwmon_temp_label:
+ *str = data->labels[channel];
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int emc1812_set_hyst(struct emc1812_data *data, int channel, unsigned int val)
+{
+ int hyst, ret;
+ int limit;
+
+ /* Critical register is 8bits long and keeps only integer part of temperature */
+ ret = regmap_read(data->regmap, emc1812_temp_crit_regs[channel], &limit);
+ if (ret)
+ return ret;
+
+ hyst = clamp_val(limit - val, 0, 255);
+
+ ret = regmap_write(data->regmap, EMC1812_THRM_HYS_ADDR, hyst);
+
+ return ret;
+}
+
+static int emc1812_set_temp(struct device *dev, struct emc1812_data *data, int channel,
+ enum emc1812_limit_type map, long valh, long vall)
+{
+ u8 regh, regl;
+ int ret;
+
+ regh = emc1812_limit_regs[channel][map];
+ regl = emc1812_limit_regs_low[channel][map];
+
+ ret = regmap_write(data->regmap, regh, valh);
+ if (ret < 0)
+ return ret;
+
+ if (channel)
+ ret = regmap_write(data->regmap, regl, vall);
+
+ return ret;
+}
+
+static int emc1812_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
+ int channel, long val)
+{
+ struct emc1812_data *data = dev_get_drvdata(dev);
+ unsigned int interval;
+ long valh, vall;
+ int convrate;
+
+ switch (type) {
+ case hwmon_temp:
+ /* Range should be -64000 to 191875°C + (EMC1812_TEMP_OFFSET * 1000) */
+ val = val + (EMC1812_TEMP_OFFSET * 1000);
+ val = clamp_val(val, 0, 255875);
+ val = DIV_ROUND_CLOSEST(val, 125);
+ valh = (val >> 3) & 0xff;
+ vall = (val & 0x07) << 5;
+
+ switch (attr) {
+ case hwmon_temp_min:
+ case hwmon_temp_max:
+ return emc1812_set_temp(dev, data, channel, emc1812_temp_map[attr],
+ valh, vall);
+ case hwmon_temp_crit:
+ /* Critical temperature limit is stored on 8bits */
+ return regmap_write(data->regmap, emc1812_temp_crit_regs[channel], valh);
+ case hwmon_temp_crit_hyst:
+ /* Critical temperature hysteresis is stored on 8bits */
+ return emc1812_set_hyst(data, channel, valh);
+ default:
+ return -EOPNOTSUPP;
+ }
+ case hwmon_chip:
+ switch (attr) {
+ case hwmon_chip_update_interval:
+ interval = clamp_val(val, 0, 16000);
+ convrate = find_closest_descending(interval, emc1812_conv_time,
+ ARRAY_SIZE(emc1812_conv_time));
+ return regmap_write(data->regmap, EMC1812_CONV_ADDR, convrate);
+ default:
+ return -EOPNOTSUPP;
+ }
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int emc1812_init(struct emc1812_data *priv)
+{
+ int ret;
+ u8 val;
+
+ /*
+ * Set default values in registers. APDD, RECD12 and RECD34 are active
+ * on 0. Set ALERT pin to be in comparator mode.
+ * Set the device to be in Run (Active) state and converting on all
+ * channels.
+ * Don't change conversion rate. After reset, default is 4 conversions/seconds.
+ * The temperature measurement range is -64°C to +191.875°C.
+ */
+ val = FIELD_PREP(EMC1812_CFG_MSKAL, 1) |
+ FIELD_PREP(EMC1812_CFG_RS, 0) |
+ FIELD_PREP(EMC1812_CFG_ATTHM, 1) |
+ FIELD_PREP(EMC1812_CFG_RECD12, !priv->recd12_en) |
+ FIELD_PREP(EMC1812_CFG_RECD34, !priv->recd34_en) |
+ FIELD_PREP(EMC1812_CFG_RANGE, 1) |
+ FIELD_PREP(EMC1812_CFG_DA_ENA, 0) |
+ FIELD_PREP(EMC1812_CFG_APDD, !priv->apdd_en);
+
+ ret = regmap_write(priv->regmap, EMC1812_CFG_ADDR, val);
+ if (ret)
+ return ret;
+
+ ret = regmap_write(priv->regmap, EMC1812_THRM_HYS_ADDR, 0x0A);
+ if (ret)
+ return ret;
+
+ ret = regmap_write(priv->regmap, EMC1812_CONSEC_ALERT_ADDR, 0x70);
+ if (ret)
+ return ret;
+
+ ret = regmap_write(priv->regmap, EMC1812_FILTER_SEL_ADDR, 0);
+ if (ret)
+ return ret;
+
+ ret = regmap_write(priv->regmap, EMC1812_HOTTEST_CFG_ADDR, 0);
+ if (ret)
+ return ret;
+
+ /* Enables the beta compensation factor auto-detection function for beta1 and beta2 */
+ ret = regmap_write(priv->regmap, EMC1812_EXT1_BETA_CONFIG_ADDR,
+ EMC1812_BETA_LOCK_VAL);
+ if (ret)
+ return ret;
+
+ ret = regmap_write(priv->regmap, EMC1812_EXT2_BETA_CONFIG_ADDR,
+ EMC1812_BETA_LOCK_VAL);
+ if (ret)
+ return ret;
+
+ /* Set ideality factor for all external channels */
+ ret = regmap_write(priv->regmap, EMC1812_EXT1_IDEALITY_FACTOR_ADDR,
+ EMC1812_DEFAULT_IDEALITY_FACTOR);
+ if (ret)
+ return ret;
+
+ /* Set the ideality factor only for the channels supported by the chip */
+ if (priv->chip->phys_channels < 3)
+ return 0;
+
+ ret = regmap_write(priv->regmap, EMC1812_EXT2_IDEALITY_FACTOR_ADDR,
+ EMC1812_DEFAULT_IDEALITY_FACTOR);
+ if (ret)
+ return ret;
+
+ if (priv->chip->phys_channels < 4)
+ return 0;
+
+ ret = regmap_write(priv->regmap, EMC1812_EXT3_IDEALITY_FACTOR_ADDR,
+ EMC1812_DEFAULT_IDEALITY_FACTOR);
+ if (ret)
+ return ret;
+
+ if (priv->chip->phys_channels < 5)
+ return 0;
+
+ return regmap_write(priv->regmap, EMC1812_EXT4_IDEALITY_FACTOR_ADDR,
+ EMC1812_DEFAULT_IDEALITY_FACTOR);
+}
+
+static int emc1812_parse_fw_config(struct emc1812_data *data, struct device *dev)
+{
+ unsigned int reg_nr = 0;
+ int num_channels, ret;
+
+ /* To be able to load the driver in case we don't have device tree */
+ if (!dev_fwnode(dev)) {
+ data->active_ch_mask = BIT(data->chip->phys_channels) - 1;
+ return 0;
+ }
+
+ data->apdd_en = device_property_read_bool(dev, "microchip,enable-anti-parallel");
+ data->recd12_en = device_property_read_bool(dev, "microchip,parasitic-res-on-channel1-2");
+ data->recd34_en = device_property_read_bool(dev, "microchip,parasitic-res-on-channel3-4");
+
+ num_channels = device_get_child_node_count(dev) + 1;
+
+ if (num_channels > data->chip->phys_channels)
+ return dev_err_probe(dev, -EINVAL, "More channels than the chip supports\n");
+
+ /* Internal temperature channel is always active */
+ data->labels[reg_nr] = "internal_diode";
+ set_bit(reg_nr, &data->active_ch_mask);
+
+ device_for_each_child_node_scoped(dev, child) {
+ ret = fwnode_property_read_u32(child, "reg", ®_nr);
+ if (ret || reg_nr >= data->chip->phys_channels)
+ return dev_err_probe(dev, -EINVAL,
+ "The index of the channels does not match the chip\n");
+ /* Mark external channel as active */
+ set_bit(reg_nr, &data->active_ch_mask);
+
+ fwnode_property_read_string(child, "label", &data->labels[reg_nr]);
+ }
+
+ return 0;
+}
+
+static int emc1812_chip_identify(struct emc1812_data *data, struct i2c_client *client)
+{
+ const struct emc1812_features *chip;
+ struct device *dev = &client->dev;
+ int ret, tmp;
+
+ ret = regmap_read(data->regmap, EMC1812_PRODUCT_ID_ADDR, &tmp);
+ if (ret)
+ return ret;
+
+ switch (tmp) {
+ case EMC1812_PID:
+ data->chip = &emc1812_chip_config;
+ break;
+ case EMC1813_PID:
+ data->chip = &emc1813_chip_config;
+ break;
+ case EMC1814_PID:
+ data->chip = &emc1814_chip_config;
+ break;
+ case EMC1815_PID:
+ data->chip = &emc1815_chip_config;
+ break;
+ case EMC1833_PID:
+ data->chip = &emc1833_chip_config;
+ break;
+ default:
+ /*
+ * If failed to identify the hardware based on internal registers,
+ * try using fallback compatible in device tree to deal with some
+ * newer part number.
+ */
+ chip = i2c_get_match_data(client);
+ if (!chip)
+ return -ENODEV;
+
+ dev_warn(dev, "devicetree data does not match the real hardware id: %x\n", tmp);
+
+ data->chip = chip;
+
+ return 0;
+ }
+
+ return 0;
+}
+
+static const struct hwmon_ops emc1812_ops = {
+ .is_visible = emc1812_is_visible,
+ .read = emc1812_read,
+ .read_string = emc1812_read_string,
+ .write = emc1812_write,
+};
+
+static const struct hwmon_chip_info emc1812_chip_info = {
+ .ops = &emc1812_ops,
+ .info = emc1812_info,
+};
+
+static int emc1812_probe(struct i2c_client *client)
+{
+ struct device *dev = &client->dev;
+ struct emc1812_data *data;
+ struct device *hwmon_dev;
+ int ret;
+
+ data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->regmap = devm_regmap_init_i2c(client, &emc1812_regmap_config);
+ if (IS_ERR(data->regmap))
+ return dev_err_probe(dev, PTR_ERR(data->regmap),
+ "Cannot initialize register map\n");
+
+ ret = emc1812_chip_identify(data, client);
+ if (ret)
+ return dev_err_probe(dev, ret, "Chip identification fails\n");
+
+ ret = emc1812_parse_fw_config(data, dev);
+ if (ret)
+ return ret;
+
+ ret = emc1812_init(data);
+ if (ret)
+ return dev_err_probe(dev, ret, "Cannot initialize device\n");
+
+ hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
+ &emc1812_chip_info, NULL);
+
+ return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id emc1812_id[] = {
+ { .name = "emc1812", .driver_data = (kernel_ulong_t)&emc1812_chip_config },
+ { .name = "emc1813", .driver_data = (kernel_ulong_t)&emc1813_chip_config },
+ { .name = "emc1814", .driver_data = (kernel_ulong_t)&emc1814_chip_config },
+ { .name = "emc1815", .driver_data = (kernel_ulong_t)&emc1815_chip_config },
+ { .name = "emc1833", .driver_data = (kernel_ulong_t)&emc1833_chip_config },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, emc1812_id);
+
+static const struct of_device_id emc1812_of_match[] = {
+ {
+ .compatible = "microchip,emc1812",
+ .data = &emc1812_chip_config
+ },
+ {
+ .compatible = "microchip,emc1813",
+ .data = &emc1813_chip_config
+ },
+ {
+ .compatible = "microchip,emc1814",
+ .data = &emc1814_chip_config
+ },
+ {
+ .compatible = "microchip,emc1815",
+ .data = &emc1815_chip_config
+ },
+ {
+ .compatible = "microchip,emc1833",
+ .data = &emc1833_chip_config
+ },
+ { }
+};
+MODULE_DEVICE_TABLE(of, emc1812_of_match);
+
+static struct i2c_driver emc1812_driver = {
+ .driver = {
+ .name = "emc1812",
+ .of_match_table = emc1812_of_match,
+ },
+ .probe = emc1812_probe,
+ .id_table = emc1812_id,
+};
+module_i2c_driver(emc1812_driver);
+
+MODULE_AUTHOR("Marius Cristea <marius.cristea@microchip.com>");
+MODULE_DESCRIPTION("EMC1812/13/14/15/33 high-accuracy remote diode temperature monitor Driver");
+MODULE_LICENSE("GPL");
--
2.51.0
^ permalink raw reply related [flat|nested] 4+ messages in thread