MAX31827 is a low-power temperature switch with I2C interface. The device is a ±1°C accuracy from -40°C to +125°C (12 bits) local temperature switch and sensor with I2C/SM- Bus interface. The combination of small 6-bump wafer-lev- el package (WLP) and high accuracy makes this temper- ature sensor/switch ideal for a wide range of applications. Signed-off-by: Daniel Matyas <daniel.matyas@xxxxxxxxxx> --- v10 -> v11: Modified compatible field of the of_device_id struct from "max31827" to "adi,max31827". Now it matches the binding. v9 -> v10: Added a proper change log. v8 -> v9: No change. v7 -> v8: Initialised ret in max31827_read function, so that it has a value, even if 'type == hwmon_chip && attr != hwmon_chip_update_interval'. (in reality it will never go there, but needed to this this, because compiler warning) Reported-by: kernel test robot <lkp@xxxxxxxxx> Link: https://lore.kernel.org/oe-kbuild-all/202305112351.DBkFfs76-lkp@xxxxxxxxx/ v6 -> v7 : Used goto instead of return in write_alarm_val function. Unlocked mutex in goto label. Used mutex for enable. Now update_interval can only be modified if the device is enabled. I did this, b.c. modifying the update interval, when the device is in shutdown mode, automatically enables the device. v5 -> v6: Corrected the mistakes with mutex. Explained why I shift the last 4 bits in the .rst file. (because the LSB is 0.0625 degrees Celsius). v4 -> v5: Used sign_extend32 to convert to and from milli-degrees. v3 -> v4: Made consistency tweaks. Extended mutex_lock to every instance of reading from or writing to st->enable. Added conversion to and from milli-degrees. Added of_table. v2 -> v3: Added mutex protection to reading and writing to configuration register. Dropped of_table. Converted update_interval to Hertz. v1 -> v2: Added max31827.rst documentation. Removed unused defines. Removed i2c_client from private struct. Made code consistent and cleaner. Resolved ABI abuse in hwmon_temp_enable. Added alarm attribute support. Added write_alarm_value function to put the device in shutdown mode before changing the alarm value and hysteresis registers. Removed redundant error message if something went wrong with regmap_init. Used sizeof(*st) instead of sizeof(struct max31827_state) in kzalloc. Documentation/hwmon/index.rst | 1 + Documentation/hwmon/max31827.rst | 90 ++++++ MAINTAINERS | 2 + drivers/hwmon/Kconfig | 11 + drivers/hwmon/Makefile | 2 +- drivers/hwmon/max31827.c | 466 +++++++++++++++++++++++++++++++ 6 files changed, 571 insertions(+), 1 deletion(-) create mode 100644 Documentation/hwmon/max31827.rst create mode 100644 drivers/hwmon/max31827.c diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst index fa1208c62855..8cc0922f3b36 100644 --- a/Documentation/hwmon/index.rst +++ b/Documentation/hwmon/index.rst @@ -140,6 +140,7 @@ Hardware Monitoring Kernel Drivers max31760 max31785 max31790 + max31827 max34440 max6620 max6639 diff --git a/Documentation/hwmon/max31827.rst b/Documentation/hwmon/max31827.rst new file mode 100644 index 000000000000..b0971d05b8a4 --- /dev/null +++ b/Documentation/hwmon/max31827.rst @@ -0,0 +1,90 @@ +.. SPDX-License-Identifier: GPL-2.0 + +Kernel driver max31827 +====================== + +Supported chips: + + * Maxim MAX31827 + + Prefix: 'max31827' + + Addresses scanned: I2C 0x40 - 0x5f + + Datasheet: Publicly available at the Analog Devices website + + * Maxim MAX31828 + + Prefix: 'max31828' + + Addresses scanned: I2C 0x40 - 0x5f + + Datasheet: Publicly available at the Analog Devices website + + * Maxim MAX31829 + + Prefix: 'max31829' + + Addresses scanned: I2C 0x40 - 0x5f + + Datasheet: Publicly available at the Analog Devices website + + +Authors: + - Daniel Matyas <daniel.matyas@xxxxxxxxxx> + +Description +----------- + +The chips supported by this driver are quite similar. The only difference +between them is found in the default power-on behaviour of the chips. While the +MAX31827's fault queue is set to 1, the other two chip's fault queue is set to +4. Besides this, the MAX31829's alarm active state is high, while the other two +chip's alarms are active on low. It is important to note that the chips can be +configured to operate in the same manner with 1 write operation to the +configuration register. From here on, we will refer to all these chips as +MAX31827. + +MAX31827 implements a temperature sensor with a 6 WLP packaging scheme. This +sensor measures the temperature of the chip itself. + +MAX31827 has low and over temperature alarms with an effective value and a +hysteresis value: -40 and -30 degrees for under temperature alarm and +100 and ++90 degrees for over temperature alarm. + +The alarm can be configured in comparator and interrupt mode. Currently only +comparator mode is implemented. In Comparator mode, the OT/UT status bits have a +value of 1 when the temperature rises above the TH value or falls below TL, +which is also subject to the Fault Queue selection. OT status returns to 0 when +the temperature drops below the TH_HYST value or when shutdown mode is entered. +Similarly, UT status returns to 0 when the temperature rises above TL_HYST value +or when shutdown mode is entered. + +Putting the MAX31827 into shutdown mode also resets the OT/UT status bits. Note +that if the mode is changed while OT/UT status bits are set, an OT/UT status +reset may be required before it begins to behave normally. To prevent this, +it is recommended to perform a read of the configuration/status register to +clear the status bits before changing the operating mode. + +The conversions can be manual with the one-shot functionality and automatic with +a set frequency. When powered on, the chip measures temperatures with 1 conv/s. +Enabling the device when it is already enabled has the side effect of setting +the conversion frequency to 1 conv/s. The conversion time varies depending on +the resolution. The conversion time doubles with every bit of increased +resolution. For 10 bit resolution 35ms are needed, while for 12 bit resolution +(default) 140ms. When chip is in shutdown mode and a read operation is +requested, one-shot is triggered, the device waits for 140 (conversion time) + 1 +(error) ms, and only after that is the temperature value register read. + +The LSB of the temperature values is 0.0625 degrees Celsius, but the values of +the temperatures are displayed in milli-degrees. This means, that some data is +lost. The step between 2 consecutive values is 62 or 63. This effect can be seen +in the writing of alarm values too. For positive numbers the user-input value +will always be rounded down to the nearest possible value, for negative numbers +the user-input will always be rounded up to the nearest possible value. + +Notes +----- + +Currently fault queue, alarm polarity and resolution cannot be modified. +PEC is not implemented either. diff --git a/MAINTAINERS b/MAINTAINERS index 752c7e9c4e4a..53f5bd58989a 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -12618,6 +12618,8 @@ L: linux-hwmon@xxxxxxxxxxxxxxx S: Supported W: http://ez.analog.com/community/linux-device-drivers F: Documentation/devicetree/bindings/hwmon/adi,max31827.yaml +F: Documentation/hwmon/max31827.rst +F: drivers/hwmon/max31827.c MAX6650 HARDWARE MONITOR AND FAN CONTROLLER DRIVER L: linux-hwmon@xxxxxxxxxxxxxxx diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig index fc640201a2de..12bd17075dc4 100644 --- a/drivers/hwmon/Kconfig +++ b/drivers/hwmon/Kconfig @@ -1097,6 +1097,17 @@ config SENSORS_MAX31760 This driver can also be built as a module. If so, the module will be called max31760. +config MAX31827 + tristate "MAX31827 low-power temperature switch and similar devices" + depends on I2C + select REGMAP_I2C + help + If you say yes here you get support for MAX31827, MAX31828 and + MAX31829 low-power temperature switches and sensors connected with I2C. + + This driver can also be built as a module. If so, the module + will be called max31827. + config SENSORS_MAX6620 tristate "Maxim MAX6620 fan controller" depends on I2C diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile index cd8c568c80a9..8a8021f9ca9e 100644 --- a/drivers/hwmon/Makefile +++ b/drivers/hwmon/Makefile @@ -149,6 +149,7 @@ obj-$(CONFIG_SENSORS_MAX6642) += max6642.o obj-$(CONFIG_SENSORS_MAX6650) += max6650.o obj-$(CONFIG_SENSORS_MAX6697) += max6697.o obj-$(CONFIG_SENSORS_MAX31790) += max31790.o +obj-$(CONFIG_MAX31827) += max31827.o obj-$(CONFIG_SENSORS_MC13783_ADC)+= mc13783-adc.o obj-$(CONFIG_SENSORS_MC34VR500) += mc34vr500.o obj-$(CONFIG_SENSORS_MCP3021) += mcp3021.o @@ -224,4 +225,3 @@ obj-$(CONFIG_SENSORS_PECI) += peci/ obj-$(CONFIG_PMBUS) += pmbus/ ccflags-$(CONFIG_HWMON_DEBUG_CHIP) := -DDEBUG - diff --git a/drivers/hwmon/max31827.c b/drivers/hwmon/max31827.c new file mode 100644 index 000000000000..66f5fcf937ff --- /dev/null +++ b/drivers/hwmon/max31827.c @@ -0,0 +1,466 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * max31827.c - Support for Maxim Low-Power Switch + * + * Copyright (c) 2023 Daniel Matyas <daniel.matyas@xxxxxxxxxx> + */ + +#include <linux/bitfield.h> +#include <linux/bitops.h> +#include <linux/delay.h> +#include <linux/hwmon.h> +#include <linux/i2c.h> +#include <linux/mutex.h> +#include <linux/regmap.h> + +#define MAX31827_T_REG 0x0 +#define MAX31827_CONFIGURATION_REG 0x2 +#define MAX31827_TH_REG 0x4 +#define MAX31827_TL_REG 0x6 +#define MAX31827_TH_HYST_REG 0x8 +#define MAX31827_TL_HYST_REG 0xA + +#define MAX31827_CONFIGURATION_1SHOT_MASK BIT(0) +#define MAX31827_CONFIGURATION_CNV_RATE_MASK GENMASK(3, 1) +#define MAX31827_CONFIGURATION_U_TEMP_STAT_MASK BIT(14) +#define MAX31827_CONFIGURATION_O_TEMP_STAT_MASK BIT(15) + +#define MAX31827_12_BIT_CNV_TIME 141 + +#define MAX31827_CNV_1_DIV_64_HZ 0x1 +#define MAX31827_CNV_1_DIV_32_HZ 0x2 +#define MAX31827_CNV_1_DIV_16_HZ 0x3 +#define MAX31827_CNV_1_DIV_4_HZ 0x4 +#define MAX31827_CNV_1_HZ 0x5 +#define MAX31827_CNV_4_HZ 0x6 +#define MAX31827_CNV_8_HZ 0x7 + +#define MAX31827_16_BIT_TO_M_DGR(x) (sign_extend32(x, 15) * 1000 / 16) +#define MAX31827_M_DGR_TO_16_BIT(x) (((x) << 4) / 1000) +#define MAX31827_DEVICE_ENABLE(x) ((x) ? 0xA : 0x0) + +struct max31827_state { + /* + * Prevent simultaneous access to the i2c client. + */ + struct mutex lock; + struct regmap *regmap; + bool enable; +}; + +static const struct regmap_config max31827_regmap = { + .reg_bits = 8, + .val_bits = 16, + .max_register = 0xA, +}; + +static int write_alarm_val(struct max31827_state *st, unsigned int reg, + long val) +{ + unsigned int cfg; + unsigned int tmp; + int ret; + + val = MAX31827_M_DGR_TO_16_BIT(val); + + /* + * Before the Temperature Threshold Alarm and Alarm Hysteresis Threshold + * register values are changed over I2C, the part must be in shutdown + * mode. + * + * Mutex is used to ensure, that some other process doesn't change the + * configuration register. + */ + mutex_lock(&st->lock); + + if (!st->enable) { + ret = regmap_write(st->regmap, reg, val); + goto unlock; + } + + ret = regmap_read(st->regmap, MAX31827_CONFIGURATION_REG, &cfg); + if (ret) + goto unlock; + + tmp = cfg & ~(MAX31827_CONFIGURATION_1SHOT_MASK | + MAX31827_CONFIGURATION_CNV_RATE_MASK); + ret = regmap_write(st->regmap, MAX31827_CONFIGURATION_REG, tmp); + if (ret) + goto unlock; + + ret = regmap_write(st->regmap, reg, val); + if (ret) + goto unlock; + + ret = regmap_write(st->regmap, MAX31827_CONFIGURATION_REG, cfg); + +unlock: + mutex_unlock(&st->lock); + return ret; +} + +static umode_t max31827_is_visible(const void *state, + enum hwmon_sensor_types type, u32 attr, + int channel) +{ + if (type == hwmon_temp) { + switch (attr) { + case hwmon_temp_enable: + case hwmon_temp_max: + case hwmon_temp_min: + case hwmon_temp_max_hyst: + case hwmon_temp_min_hyst: + return 0644; + case hwmon_temp_input: + case hwmon_temp_min_alarm: + case hwmon_temp_max_alarm: + return 0444; + default: + return 0; + } + } else if (type == hwmon_chip) { + if (attr == hwmon_chip_update_interval) + return 0644; + } + + return 0; +} + +static int max31827_read(struct device *dev, enum hwmon_sensor_types type, + u32 attr, int channel, long *val) +{ + struct max31827_state *st = dev_get_drvdata(dev); + unsigned int uval; + int ret = 0; + + switch (type) { + case hwmon_temp: + switch (attr) { + case hwmon_temp_enable: + ret = regmap_read(st->regmap, + MAX31827_CONFIGURATION_REG, &uval); + if (ret) + break; + + uval = FIELD_GET(MAX31827_CONFIGURATION_1SHOT_MASK | + MAX31827_CONFIGURATION_CNV_RATE_MASK, + uval); + *val = !!uval; + + break; + case hwmon_temp_input: + mutex_lock(&st->lock); + + if (!st->enable) { + /* + * This operation requires mutex protection, + * because the chip configuration should not + * be changed during the conversion process. + */ + + ret = regmap_update_bits(st->regmap, + MAX31827_CONFIGURATION_REG, + MAX31827_CONFIGURATION_1SHOT_MASK, + 1); + if (ret) { + mutex_unlock(&st->lock); + return ret; + } + + msleep(MAX31827_12_BIT_CNV_TIME); + } + ret = regmap_read(st->regmap, MAX31827_T_REG, &uval); + + mutex_unlock(&st->lock); + + if (ret) + break; + + *val = MAX31827_16_BIT_TO_M_DGR(uval); + + break; + case hwmon_temp_max: + ret = regmap_read(st->regmap, MAX31827_TH_REG, &uval); + if (ret) + break; + + *val = MAX31827_16_BIT_TO_M_DGR(uval); + break; + case hwmon_temp_max_hyst: + ret = regmap_read(st->regmap, MAX31827_TH_HYST_REG, + &uval); + if (ret) + break; + + *val = MAX31827_16_BIT_TO_M_DGR(uval); + break; + case hwmon_temp_max_alarm: + ret = regmap_read(st->regmap, + MAX31827_CONFIGURATION_REG, &uval); + if (ret) + break; + + *val = FIELD_GET(MAX31827_CONFIGURATION_O_TEMP_STAT_MASK, + uval); + break; + case hwmon_temp_min: + ret = regmap_read(st->regmap, MAX31827_TL_REG, &uval); + if (ret) + break; + + *val = MAX31827_16_BIT_TO_M_DGR(uval); + break; + case hwmon_temp_min_hyst: + ret = regmap_read(st->regmap, MAX31827_TL_HYST_REG, + &uval); + if (ret) + break; + + *val = MAX31827_16_BIT_TO_M_DGR(uval); + break; + case hwmon_temp_min_alarm: + ret = regmap_read(st->regmap, + MAX31827_CONFIGURATION_REG, &uval); + if (ret) + break; + + *val = FIELD_GET(MAX31827_CONFIGURATION_U_TEMP_STAT_MASK, + uval); + break; + default: + ret = -EOPNOTSUPP; + break; + } + + break; + + case hwmon_chip: + if (attr == hwmon_chip_update_interval) { + ret = regmap_read(st->regmap, + MAX31827_CONFIGURATION_REG, &uval); + if (ret) + break; + + uval = FIELD_GET(MAX31827_CONFIGURATION_CNV_RATE_MASK, + uval); + switch (uval) { + case MAX31827_CNV_1_DIV_64_HZ: + *val = 64000; + break; + case MAX31827_CNV_1_DIV_32_HZ: + *val = 32000; + break; + case MAX31827_CNV_1_DIV_16_HZ: + *val = 16000; + break; + case MAX31827_CNV_1_DIV_4_HZ: + *val = 4000; + break; + case MAX31827_CNV_1_HZ: + *val = 1000; + break; + case MAX31827_CNV_4_HZ: + *val = 250; + break; + case MAX31827_CNV_8_HZ: + *val = 125; + break; + default: + *val = 0; + break; + } + } + break; + + default: + ret = -EOPNOTSUPP; + break; + } + + return ret; +} + +static int max31827_write(struct device *dev, enum hwmon_sensor_types type, + u32 attr, int channel, long val) +{ + struct max31827_state *st = dev_get_drvdata(dev); + int ret; + + switch (type) { + case hwmon_temp: + switch (attr) { + case hwmon_temp_enable: + if (val >> 1) + return -EOPNOTSUPP; + + mutex_lock(&st->lock); + /** + * The chip should not be enabled while a conversion is + * performed. Neither should the chip be enabled when + * the alarm values are changed. + */ + + st->enable = val; + + ret = regmap_update_bits(st->regmap, + MAX31827_CONFIGURATION_REG, + MAX31827_CONFIGURATION_1SHOT_MASK | + MAX31827_CONFIGURATION_CNV_RATE_MASK, + MAX31827_DEVICE_ENABLE(val)); + + mutex_unlock(&st->lock); + + return ret; + + case hwmon_temp_max: + return write_alarm_val(st, MAX31827_TH_REG, val); + + case hwmon_temp_max_hyst: + return write_alarm_val(st, MAX31827_TH_HYST_REG, val); + + case hwmon_temp_min: + return write_alarm_val(st, MAX31827_TL_REG, val); + + case hwmon_temp_min_hyst: + return write_alarm_val(st, MAX31827_TL_HYST_REG, val); + + default: + return -EOPNOTSUPP; + } + + case hwmon_chip: + if (attr == hwmon_chip_update_interval) { + if (!st->enable) + return -EOPNOTSUPP; + + switch (val) { + case 125: + val = MAX31827_CNV_8_HZ; + break; + case 250: + val = MAX31827_CNV_4_HZ; + break; + case 1000: + val = MAX31827_CNV_1_HZ; + break; + case 4000: + val = MAX31827_CNV_1_DIV_4_HZ; + break; + case 16000: + val = MAX31827_CNV_1_DIV_16_HZ; + break; + case 32000: + val = MAX31827_CNV_1_DIV_32_HZ; + break; + case 64000: + val = MAX31827_CNV_1_DIV_64_HZ; + break; + default: + return -EOPNOTSUPP; + } + + val = FIELD_PREP(MAX31827_CONFIGURATION_CNV_RATE_MASK, + val); + + return regmap_update_bits(st->regmap, + MAX31827_CONFIGURATION_REG, + MAX31827_CONFIGURATION_CNV_RATE_MASK, + val); + } + break; + + default: + return -EOPNOTSUPP; + } + + return -EOPNOTSUPP; +} + +static int max31827_init_client(struct max31827_state *st) +{ + st->enable = true; + + return regmap_update_bits(st->regmap, MAX31827_CONFIGURATION_REG, + MAX31827_CONFIGURATION_1SHOT_MASK | + MAX31827_CONFIGURATION_CNV_RATE_MASK, + MAX31827_DEVICE_ENABLE(1)); +} + +static const struct hwmon_channel_info *max31827_info[] = { + HWMON_CHANNEL_INFO(temp, HWMON_T_ENABLE | HWMON_T_INPUT | HWMON_T_MIN | + HWMON_T_MIN_HYST | HWMON_T_MIN_ALARM | + HWMON_T_MAX | HWMON_T_MAX_HYST | + HWMON_T_MAX_ALARM), + HWMON_CHANNEL_INFO(chip, HWMON_C_UPDATE_INTERVAL), + NULL, +}; + +static const struct hwmon_ops max31827_hwmon_ops = { + .is_visible = max31827_is_visible, + .read = max31827_read, + .write = max31827_write, +}; + +static const struct hwmon_chip_info max31827_chip_info = { + .ops = &max31827_hwmon_ops, + .info = max31827_info, +}; + +static int max31827_probe(struct i2c_client *client) +{ + struct device *dev = &client->dev; + struct device *hwmon_dev; + struct max31827_state *st; + int err; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA)) + return -EOPNOTSUPP; + + st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL); + if (!st) + return -ENOMEM; + + mutex_init(&st->lock); + + st->regmap = devm_regmap_init_i2c(client, &max31827_regmap); + if (IS_ERR(st->regmap)) + return dev_err_probe(dev, PTR_ERR(st->regmap), + "Failed to allocate regmap.\n"); + + err = max31827_init_client(st); + if (err) + return err; + + hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, st, + &max31827_chip_info, + NULL); + + return PTR_ERR_OR_ZERO(hwmon_dev); +} + +static const struct i2c_device_id max31827_i2c_ids[] = { + { "max31827", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, max31827_i2c_ids); + +static const struct of_device_id max31827_of_match[] = { + { .compatible = "adi,max31827" }, + { } +}; +MODULE_DEVICE_TABLE(of, max31827_of_match); + +static struct i2c_driver max31827_driver = { + .class = I2C_CLASS_HWMON, + .driver = { + .name = "max31827", + .of_match_table = max31827_of_match, + }, + .probe_new = max31827_probe, + .id_table = max31827_i2c_ids, +}; +module_i2c_driver(max31827_driver); + +MODULE_AUTHOR("Daniel Matyas <daniel.matyas@xxxxxxxxxx>"); +MODULE_DESCRIPTION("Maxim MAX31827 low-power temperature switch driver"); +MODULE_LICENSE("GPL"); -- 2.34.1
