[v10] iio: temperature: Add driver support for Maxim MAX30208
Commit Message
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
Comments
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;
> >> +}
> >> +
@@ -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
@@ -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
@@ -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
new file mode 100644
@@ -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");