| Message ID | 20221118153729.762018-1-rajat.khandelwal@linux.intel.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v10] iio: temperature: Add driver support for Maxim MAX30208 | expand |
On Fri, 18 Nov 2022 21:07:29 +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. Blank line here. > Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX30208.pdf > Datasheet part of the tags block, so no blank line between that and the SoB. That makes life easy for tools parsing git messages. > Signed-off-by: Rajat Khandelwal <rajat.khandelwal@linux.intel.com> One query inline. Basically boils down to what we do after overflow occurs. I assume you are right and the first reading is the most recent, but I think we still want to flush the whole fifo in that case to get back to a sane state for future reads. Jonathan > +/** > + * 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--; > + } Hmm. Given you've been poking this a lot, I guess this works and the part is as just odd. Just to check one last case... Does max30208_request() guarantee we can't get... 1. Read first time, overflow set so we read latest result - leaving 31 ancient values in the fifo. 2. Read again really quickly and get those ancient values. ? Perhaps we should flush out those unwanted values from the fifo, so after overflow we get back to a normal state rather than immediately overflowing again. More than possible that I still don't understand how this device works though! > + > +unlock: > + mutex_unlock(&data->lock); > + return ret; > +} > +
On Fri, 18 Nov 2022 18:27:10 +0530 Rajat Khandelwal <rajat.khandelwal@linux.intel.com> wrote: > Have provided inline comments. > Please provide your comments for me to spin a v11 :) > > On 11/17/2022 10:00 PM, Jonathan Cameron wrote: > > On Fri, 18 Nov 2022 21:07:29 +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. > > Blank line here. > > > >> Datasheet:https://datasheets.maximintegrated.com/en/ds/MAX30208.pdf > >> > > Datasheet part of the tags block, so no blank line between that and the SoB. > > That makes life easy for tools parsing git messages. > > - Got it. Will do that. > > > > >> Signed-off-by: Rajat Khandelwal<rajat.khandelwal@linux.intel.com> > > One query inline. Basically boils down to what we do after > > overflow occurs. I assume you are right and the first reading is the most recent, but > > I think we still want to flush the whole fifo in that case to get back to > > a sane state for future reads. > > > > Jonathan > > > >> +/** > >> + * 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--; > >> + } > > Hmm. Given you've been poking this a lot, I guess this works and the part is > > as just odd. Just to check one last case... Does max30208_request() guarantee we can't > > get... > > > > 1. Read first time, overflow set so we read latest result - leaving > > 31 ancient values in the fifo. > > 2. Read again really quickly and get those ancient values. > > ? > > > > Perhaps we should flush out those unwanted values from the fifo, so after > > overflow we get back to a normal state rather than immediately overflowing again. > > > > More than possible that I still don't understand how this device works though! > > - Ok, so whenever user wants a temperature reading, conversion first takes place and then > the reading gets returned. So, user will always get the latest converted reading despite > the number of ancient readings. > Flushing everytime we get an overflow is not required I think because even though overflow > could happen again, user still gets the latest updated reading. Also, I plan to incorporate > buffered flow in IIO. Even though, I think let FIFO remain intact because it doesn't impact > the recent readings. Fair enough. Sounds like yes, we are guaranteed there will always be a new reading before we start popping entries off the fifo again. If that's the case, all is fine as is - was just really hard to figure that out from the code / datasheet, so I wanted to check. Jonathan > > >> + > >> +unlock: > >> + mutex_unlock(&data->lock); > >> + return ret; > >> +} > >> +
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");
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> --- 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