Maxim MAX30208 is a digital temperature sensor with 0.1°C accuracy. Add support for max30208 driver in iio subsystem. Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX30208.pdf Signed-off-by: Rajat Khandelwal <rajat.khandelwal@xxxxxxxxxxxxxxx> --- v6: Converted usleep_range to msleep as delay is quite large v5: 1. Fixed comment position in max30208_request 2. Use of local u8 variable to build register values 3. Using u8 instead of s8 in data_count 4. Removed global MAX30208_RES_MILLICELCIUS 5. Removed 'comma' on NULL terminators v4: Version comments go below line separator of signed-off-by v3: Release the mutex lock after error gets returned v2: 1. Removed TODO 2. Removed unnecessary blank spaces 3. Corrected MC->MILLICELCIUS 4. Comments added wherever required 5. dev_err on i2c fails 6. Rearranged some flows 7. Removed PROCESSED 8. int error return on gpio setup 9. device_register at the end of probe 10. Return on unsuccessful reset 11. acpi_match_table and of_match_table added 12. Minor quirks MAINTAINERS | 6 + drivers/iio/temperature/Kconfig | 10 + drivers/iio/temperature/Makefile | 1 + drivers/iio/temperature/max30208.c | 323 +++++++++++++++++++++++++++++ 4 files changed, 340 insertions(+) create mode 100644 drivers/iio/temperature/max30208.c diff --git a/MAINTAINERS b/MAINTAINERS index f1390b8270b2..7f1fd2e31b94 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -12373,6 +12373,12 @@ S: Maintained F: Documentation/devicetree/bindings/regulator/maxim,max20086.yaml F: drivers/regulator/max20086-regulator.c +MAXIM MAX30208 TEMPERATURE SENSOR DRIVER +M: Rajat Khandelwal <rajat.khandelwal@xxxxxxxxxxxxxxx> +L: linux-iio@xxxxxxxxxxxxxxx +S: Maintained +F: drivers/iio/temperature/max30208.c + MAXIM MAX77650 PMIC MFD DRIVER M: Bartosz Golaszewski <brgl@xxxxxxxx> L: linux-kernel@xxxxxxxxxxxxxxx diff --git a/drivers/iio/temperature/Kconfig b/drivers/iio/temperature/Kconfig index e8ed849e3b76..ed384f33e0c7 100644 --- a/drivers/iio/temperature/Kconfig +++ b/drivers/iio/temperature/Kconfig @@ -128,6 +128,16 @@ config TSYS02D This driver can also be built as a module. If so, the module will be called tsys02d. +config MAX30208 + tristate "Maxim MAX30208 digital temperature sensor" + depends on I2C + help + If you say yes here you get support for Maxim MAX30208 + digital temperature sensor connected via I2C. + + This driver can also be built as a module. If so, the module + will be called max30208. + config MAX31856 tristate "MAX31856 thermocouple sensor" depends on SPI diff --git a/drivers/iio/temperature/Makefile b/drivers/iio/temperature/Makefile index dd08e562ffe0..dfec8c6d3019 100644 --- a/drivers/iio/temperature/Makefile +++ b/drivers/iio/temperature/Makefile @@ -7,6 +7,7 @@ obj-$(CONFIG_IQS620AT_TEMP) += iqs620at-temp.o obj-$(CONFIG_LTC2983) += ltc2983.o obj-$(CONFIG_HID_SENSOR_TEMP) += hid-sensor-temperature.o obj-$(CONFIG_MAXIM_THERMOCOUPLE) += maxim_thermocouple.o +obj-$(CONFIG_MAX30208) += max30208.o obj-$(CONFIG_MAX31856) += max31856.o obj-$(CONFIG_MAX31865) += max31865.o obj-$(CONFIG_MLX90614) += mlx90614.o diff --git a/drivers/iio/temperature/max30208.c b/drivers/iio/temperature/max30208.c new file mode 100644 index 000000000000..41b26755ce27 --- /dev/null +++ b/drivers/iio/temperature/max30208.c @@ -0,0 +1,323 @@ +// SPDX-License-Identifier: GPL-2.0-only + +/* + * Copyright (c) Rajat Khandelwal <rajat.khandelwal@xxxxxxxxxxxxxxx> + * + * Maxim MAX30208 digital temperature sensor with 0.1°C accuracy + * (7-bit I2C slave address (0x50 - 0x53)) + * + * Note: This driver sets GPIO1 to behave as input for temperature + * conversion and GPIO0 to act as interrupt for temperature conversion. + */ + +#include <linux/bitops.h> +#include <linux/delay.h> +#include <linux/iio/iio.h> +#include <linux/i2c.h> +#include <linux/module.h> +#include <linux/types.h> + +#define MAX30208_DRV_NAME "max30208" + +#define MAX30208_STATUS 0x00 +#define MAX30208_STATUS_TEMP_RDY BIT(0) +#define MAX30208_INT_ENABLE 0x01 +#define MAX30208_INT_ENABLE_TEMP_RDY BIT(0) + +#define MAX30208_FIFO_OVF_CNTR 0x06 +#define MAX30208_FIFO_DATA_CNTR 0x07 +#define MAX30208_FIFO_DATA 0x08 + +#define MAX30208_SYSTEM_CTRL 0x0c +#define MAX30208_SYSTEM_CTRL_RESET 0x01 + +#define MAX30208_TEMP_SENSOR_SETUP 0x14 +#define MAX30208_TEMP_SENSOR_SETUP_CONV BIT(0) + +#define MAX30208_GPIO_SETUP 0x20 +#define MAX30208_GPIO1_SETUP GENMASK(7, 6) +#define MAX30208_GPIO0_SETUP GENMASK(1, 0) +#define MAX30208_GPIO_CTRL 0x21 +#define MAX30208_GPIO1_CTRL BIT(3) +#define MAX30208_GPIO0_CTRL BIT(0) + +struct max30208_data { + struct i2c_client *client; + struct iio_dev *indio_dev; + struct mutex lock; /* Lock to prevent concurrent reads */ +}; + +static const struct iio_chan_spec max30208_channels[] = { + { + .type = IIO_TEMP, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), + }, +}; + +/** + * max30208_request() - Request a reading + * @data: Struct comprising member elements of the device + * + * Requests a reading from the device and waits until the conversion is ready. + */ +static int max30208_request(struct max30208_data *data) +{ + /* + * Sensor can take up to 500 ms to respond so execute a total of + * 10 retries to give the device sufficient time. + */ + int retries = 10; + u8 regval; + int ret; + + ret = i2c_smbus_read_byte_data(data->client, MAX30208_TEMP_SENSOR_SETUP); + if (ret < 0) { + dev_err(&data->client->dev, "Error reading reg temperature setup\n"); + return ret; + } + + regval = ret | MAX30208_TEMP_SENSOR_SETUP_CONV; + + ret = i2c_smbus_write_byte_data(data->client, MAX30208_TEMP_SENSOR_SETUP, regval); + if (ret < 0) { + dev_err(&data->client->dev, "Error writing reg temperature setup\n"); + return ret; + } + + while (retries--) { + ret = i2c_smbus_read_byte_data(data->client, MAX30208_STATUS); + if (ret < 0) { + dev_err(&data->client->dev, "Error reading reg status\n"); + goto sleep; + } + + if (ret & MAX30208_STATUS_TEMP_RDY) + return 0; + + msleep(50); + } + dev_warn(&data->client->dev, "Temperature conversion failed\n"); + + return 0; + +sleep: + msleep(50); + return 0; +} + +static int max30208_update_temp(struct max30208_data *data) +{ + u8 data_count; + int ret; + + mutex_lock(&data->lock); + + ret = max30208_request(data); + if (ret < 0) + goto unlock; + + ret = i2c_smbus_read_byte_data(data->client, MAX30208_FIFO_OVF_CNTR); + if (ret < 0) { + dev_err(&data->client->dev, "Error reading reg FIFO overflow counter\n"); + goto unlock; + } else if (!ret) { + ret = i2c_smbus_read_byte_data(data->client, + MAX30208_FIFO_DATA_CNTR); + if (ret < 0) { + dev_err(&data->client->dev, "Error reading reg FIFO data counter\n"); + goto unlock; + } + } + + data_count = ret; + + /* + * Ideally, counter should decrease by 1 each time a word is read from FIFO. + * However, practically, the device behaves erroneously and counter sometimes + * decreases by more than 1. Hence, do not loop the counter until it becomes 0 + * rather, use the exact counter value after each FIFO word is read. + * Return the last reading from FIFO as the most recently triggered one. + */ + while (data_count) { + ret = i2c_smbus_read_word_swapped(data->client, + MAX30208_FIFO_DATA); + if (ret < 0) { + dev_err(&data->client->dev, "Error reading reg FIFO data\n"); + goto unlock; + } + + data_count = i2c_smbus_read_byte_data(data->client, + MAX30208_FIFO_DATA_CNTR); + if (data_count < 0) { + dev_err(&data->client->dev, "Error reading reg FIFO data counter\n"); + ret = data_count; + goto unlock; + } + } + +unlock: + mutex_unlock(&data->lock); + return ret; +} + +static int max30208_read(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct max30208_data *data = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + ret = max30208_update_temp(data); + if (ret < 0) + return ret; + + *val = sign_extend32(ret, 15); + return IIO_VAL_INT; + + case IIO_CHAN_INFO_SCALE: + *val = 5; + return IIO_VAL_INT; + + default: + return -EINVAL; + } +} + +static int max30208_gpio_setup(struct max30208_data *data) +{ + u8 regval; + int ret; + + ret = i2c_smbus_read_byte_data(data->client, + MAX30208_GPIO_SETUP); + if (ret < 0) { + dev_err(&data->client->dev, "Error reading reg GPIO setup\n"); + return ret; + } + + /* + * Setting GPIO1 to trigger temperature conversion + * when driven low. + * Setting GPIO0 to trigger interrupt when temperature + * conversion gets completed. + */ + regval = ret | MAX30208_GPIO1_SETUP | MAX30208_GPIO0_SETUP; + ret = i2c_smbus_write_byte_data(data->client, + MAX30208_GPIO_SETUP, regval); + if (ret < 0) { + dev_err(&data->client->dev, "Error writing reg GPIO setup\n"); + return ret; + } + + ret = i2c_smbus_read_byte_data(data->client, + MAX30208_INT_ENABLE); + if (ret < 0) { + dev_err(&data->client->dev, "Error reading reg interrupt enable\n"); + return ret; + } + + /* Enabling GPIO0 interrupt */ + regval = ret | MAX30208_INT_ENABLE_TEMP_RDY; + ret = i2c_smbus_write_byte_data(data->client, + MAX30208_INT_ENABLE, regval); + if (ret < 0) { + dev_err(&data->client->dev, "Error writing reg interrupt enable\n"); + return ret; + } + + return 0; +} + +static const struct iio_info max30208_info = { + .read_raw = max30208_read, +}; + +static int max30208_probe(struct i2c_client *i2c) +{ + struct device *dev = &i2c->dev; + struct max30208_data *data; + struct iio_dev *indio_dev; + int ret; + + indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); + if (!indio_dev) + return -ENOMEM; + + data = iio_priv(indio_dev); + data->client = i2c; + mutex_init(&data->lock); + + indio_dev->name = MAX30208_DRV_NAME; + indio_dev->channels = max30208_channels; + indio_dev->num_channels = ARRAY_SIZE(max30208_channels); + indio_dev->info = &max30208_info; + indio_dev->modes = INDIO_DIRECT_MODE; + + /* Reset the device initially */ + ret = i2c_smbus_write_byte_data(data->client, MAX30208_SYSTEM_CTRL, + MAX30208_SYSTEM_CTRL_RESET); + if (ret) { + dev_err(dev, "Failure in performing reset\n"); + return ret; + } + + msleep(50); + + ret = max30208_gpio_setup(data); + if (ret < 0) + return ret; + + ret = devm_iio_device_register(dev, indio_dev); + if (ret) { + dev_err(dev, "Failed to register IIO device\n"); + return ret; + } + + return 0; +} + +static const struct i2c_device_id max30208_id_table[] = { + { "max30208" }, + { } +}; +MODULE_DEVICE_TABLE(i2c, max30208_id_table); + +static const struct acpi_device_id max30208_acpi_match[] = { + { "MAX30208" }, + { } +}; +MODULE_DEVICE_TABLE(acpi, max30208_acpi_match); + +static const struct of_device_id max30208_of_match[] = { + { .compatible = "maxim,max30208" }, + { } +}; +MODULE_DEVICE_TABLE(of, max30208_of_match); + +static struct i2c_driver max30208_driver = { + .driver = { + .name = MAX30208_DRV_NAME, + .of_match_table = max30208_of_match, + .acpi_match_table = ACPI_PTR(max30208_acpi_match), + }, + .probe_new = max30208_probe, + .id_table = max30208_id_table, +}; + +static int __init max30208_init(void) +{ + return i2c_add_driver(&max30208_driver); +} +module_init(max30208_init); + +static void __exit max30208_exit(void) +{ + i2c_del_driver(&max30208_driver); +} +module_exit(max30208_exit); + +MODULE_AUTHOR("Rajat Khandelwal <rajat.khandelwal@xxxxxxxxxxxxxxx>"); +MODULE_DESCRIPTION("Maxim MAX30208 digital temperature sensor"); +MODULE_LICENSE("GPL"); -- 2.34.1
