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SubjectRe: [PATCH v11] iio: temperature: Add driver support for Maxim MAX30208
On Tue, 22 Nov 2022 23:23:00 +0530
Rajat Khandelwal <rajat.khandelwal@linux.intel.com> wrote:

> 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@linux.intel.com>

Applied to the togreg branch of iio.git.

Thanks,

Jonathan
> ---
>
> v11: Small tweaks (blank line spacing)
>
> v10: Correcting the overflow logic
>
> v9: Repositioning register data
>
> v8:
> 1. Returning time out if conversion fails to happen
> 2. Setting rollover bit to '1' to allow FIFO overwriting
> 3. Dropping ACPI_PTR
>
> v7:
> 1. Dropped GPIOs use for now
> 2. Driver name string directly used
> 3. Mutex lock description added
> 4. Removed noisy errors and only kept errors on larger code blocks
> 5. dev_warn -> dev_err for temperature conversion failure
> 6. Improvised the logic of popping out values
> 7. Fixed line breaks
> 8. module_i2c_driver
>
> 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 | 252 +++++++++++++++++++++++++++++
> 4 files changed, 269 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@linux.intel.com>
> +L: linux-iio@vger.kernel.org
> +S: Maintained
> +F: drivers/iio/temperature/max30208.c
> +
> MAXIM MAX77650 PMIC MFD DRIVER
> M: Bartosz Golaszewski <brgl@bgdev.pl>
> L: linux-kernel@vger.kernel.org
> 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..c85c21474711
> --- /dev/null
> +++ b/drivers/iio/temperature/max30208.c
> @@ -0,0 +1,252 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +
> +/*
> + * Copyright (c) Rajat Khandelwal <rajat.khandelwal@linux.intel.com>
> + *
> + * Maxim MAX30208 digital temperature sensor with 0.1°C accuracy
> + * (7-bit I2C slave address (0x50 - 0x53))
> + */
> +
> +#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_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_FIFO_CONFIG 0x0a
> +#define MAX30208_FIFO_CONFIG_RO BIT(1)
> +
> +#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)
> +
> +struct max30208_data {
> + struct i2c_client *client;
> + struct iio_dev *indio_dev;
> + struct mutex lock; /* Lock to prevent concurrent reads of temperature readings */
> +};
> +
> +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)
> + return ret;
> +
> + regval = ret | MAX30208_TEMP_SENSOR_SETUP_CONV;
> +
> + ret = i2c_smbus_write_byte_data(data->client, MAX30208_TEMP_SENSOR_SETUP, regval);
> + if (ret)
> + return ret;
> +
> + while (retries--) {
> + ret = i2c_smbus_read_byte_data(data->client, MAX30208_STATUS);
> + if (ret < 0)
> + return ret;
> +
> + if (ret & MAX30208_STATUS_TEMP_RDY)
> + return 0;
> +
> + msleep(50);
> + }
> + dev_err(&data->client->dev, "Temperature conversion failed\n");
> +
> + return -ETIMEDOUT;
> +}
> +
> +static int max30208_update_temp(struct max30208_data *data)
> +{
> + u8 data_count;
> + int ret;
> +
> + mutex_lock(&data->lock);
> +
> + ret = max30208_request(data);
> + if (ret)
> + goto unlock;
> +
> + ret = i2c_smbus_read_byte_data(data->client, MAX30208_FIFO_OVF_CNTR);
> + if (ret < 0)
> + goto unlock;
> + else if (!ret) {
> + ret = i2c_smbus_read_byte_data(data->client, MAX30208_FIFO_DATA_CNTR);
> + if (ret < 0)
> + goto unlock;
> +
> + data_count = ret;
> + } else
> + data_count = 1;
> +
> + while (data_count) {
> + ret = i2c_smbus_read_word_swapped(data->client, MAX30208_FIFO_DATA);
> + if (ret < 0)
> + goto unlock;
> +
> + data_count--;
> + }
> +
> +unlock:
> + mutex_unlock(&data->lock);
> + return ret;
> +}
> +
> +/**
> + * max30208_config_setup() - Set up FIFO configuration register
> + * @data: Struct comprising member elements of the device
> + *
> + * Sets the rollover bit to '1' to enable overwriting FIFO during overflow.
> + */
> +static int max30208_config_setup(struct max30208_data *data)
> +{
> + u8 regval;
> + int ret;
> +
> + ret = i2c_smbus_read_byte_data(data->client, MAX30208_FIFO_CONFIG);
> + if (ret < 0)
> + return ret;
> +
> + regval = ret | MAX30208_FIFO_CONFIG_RO;
> +
> + ret = i2c_smbus_write_byte_data(data->client, MAX30208_FIFO_CONFIG, regval);
> + if (ret)
> + return ret;
> +
> + return 0;
> +}
> +
> +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 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";
> + indio_dev->channels = max30208_channels;
> + indio_dev->num_channels = ARRAY_SIZE(max30208_channels);
> + indio_dev->info = &max30208_info;
> + indio_dev->modes = INDIO_DIRECT_MODE;
> +
> + 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_config_setup(data);
> + if (ret)
> + 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",
> + .of_match_table = max30208_of_match,
> + .acpi_match_table = max30208_acpi_match,
> + },
> + .probe_new = max30208_probe,
> + .id_table = max30208_id_table,
> +};
> +module_i2c_driver(max30208_driver);
> +
> +MODULE_AUTHOR("Rajat Khandelwal <rajat.khandelwal@linux.intel.com>");
> +MODULE_DESCRIPTION("Maxim MAX30208 digital temperature sensor");
> +MODULE_LICENSE("GPL");

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