The Vishay veml3235 is a low-power ambient light sensor with I2C
interface. It provides a minimum detectable intensity of
0.0021 lx/cnt, configurable integration time and gain, and an additional
white channel to distinguish between different light sources.
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
---
MAINTAINERS | 6 +
drivers/iio/light/Kconfig | 11 +
drivers/iio/light/Makefile | 1 +
drivers/iio/light/veml3235.c | 540 +++++++++++++++++++++++++++++++++++++++++++
4 files changed, 558 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index 5ed860685cd1..ae7cb38fb64e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -24798,6 +24798,12 @@ S: Maintained
F: drivers/input/serio/userio.c
F: include/uapi/linux/userio.h
+VISHAY VEML3235 AMBIENT LIGHT SENSOR DRIVER
+M: Javier Carrasco <javier.carrasco.cruz@gmail.com>
+S: Maintained
+F: Documentation/devicetree/bindings/iio/light/vishay,veml6030.yaml
+F: drivers/iio/light/veml3235.c
+
VISHAY VEML6030 AMBIENT LIGHT SENSOR DRIVER
M: Javier Carrasco <javier.carrasco.cruz@gmail.com>
S: Maintained
diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index c38b3c603ab4..c6b7ed0c61a1 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -670,6 +670,17 @@ config VCNL4035
To compile this driver as a module, choose M here: the
module will be called vcnl4035.
+config VEML3235
+ tristate "VEML3235 ambient light sensor"
+ select REGMAP_I2C
+ depends on I2C
+ help
+ Say Y here if you want to build a driver for the Vishay VEML3235
+ ambient light sensor.
+
+ To compile this driver as a module, choose M here: the
+ module will be called veml3235.
+
config VEML6030
tristate "VEML6030 and VEML6035 ambient light sensors"
select REGMAP_I2C
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index 321010fc0b93..f14a37442712 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -62,6 +62,7 @@ obj-$(CONFIG_TSL4531) += tsl4531.o
obj-$(CONFIG_US5182D) += us5182d.o
obj-$(CONFIG_VCNL4000) += vcnl4000.o
obj-$(CONFIG_VCNL4035) += vcnl4035.o
+obj-$(CONFIG_VEML3235) += veml3235.o
obj-$(CONFIG_VEML6030) += veml6030.o
obj-$(CONFIG_VEML6040) += veml6040.o
obj-$(CONFIG_VEML6070) += veml6070.o
diff --git a/drivers/iio/light/veml3235.c b/drivers/iio/light/veml3235.c
new file mode 100644
index 000000000000..fa2141cced8f
--- /dev/null
+++ b/drivers/iio/light/veml3235.c
@@ -0,0 +1,540 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * VEML3235 Ambient Light Sensor
+ *
+ * Copyright (c) 2024, Javier Carrasco <javier.carrasco.cruz@gmail.com>
+ *
+ * Datasheet: https://www.vishay.com/docs/80131/veml3235.pdf
+ * Appnote-80222: https://www.vishay.com/docs/80222/designingveml3235.pdf
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+
+#define VEML3235_REG_CONF 0x00
+#define VEML3235_REG_WH_DATA 0x04
+#define VEML3235_REG_ALS_DATA 0x05
+#define VEML3235_REG_ID 0x09
+
+#define VEML3235_CONF_SD BIT(0)
+#define VEML3235_CONF_SD0 BIT(8)
+
+struct veml3235_rf {
+ struct regmap_field *it;
+ struct regmap_field *gain;
+ struct regmap_field *id;
+};
+
+struct veml3235_data {
+ struct i2c_client *client;
+ struct device *dev;
+ struct regmap *regmap;
+ struct veml3235_rf rf;
+ int gain;
+ int it;
+ int resolution;
+};
+
+static const int veml3235_it_times[][2] = {
+ { 0, 50000 },
+ { 0, 100000 },
+ { 0, 200000 },
+ { 0, 400000 },
+ { 0, 800000 },
+};
+
+static const int veml3235_scale_vals[] = { 1, 2, 4, 8 };
+
+static int veml3235_power_on(struct veml3235_data *data)
+{
+ int ret;
+
+ ret = regmap_clear_bits(data->regmap, VEML3235_REG_CONF,
+ VEML3235_CONF_SD | VEML3235_CONF_SD0);
+ if (ret)
+ return ret;
+
+ /* Wait 4 ms to let processor & oscillator start correctly */
+ fsleep(4000);
+
+ return 0;
+}
+
+static int veml3235_shut_down(struct veml3235_data *data)
+{
+ return regmap_set_bits(data->regmap, VEML3235_REG_CONF,
+ VEML3235_CONF_SD | VEML3235_CONF_SD0);
+}
+
+static void veml3235_shut_down_action(void *data)
+{
+ veml3235_shut_down(data);
+}
+
+enum veml3235_chan {
+ CH_ALS,
+ CH_WHITE,
+};
+
+static const struct iio_chan_spec veml3235_channels[] = {
+ {
+ .type = IIO_LIGHT,
+ .channel = CH_ALS,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_PROCESSED),
+ .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ .info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ },
+ {
+ .type = IIO_INTENSITY,
+ .channel = CH_WHITE,
+ .modified = 1,
+ .channel2 = IIO_MOD_LIGHT_BOTH,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+ .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ .info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ },
+};
+
+static const struct regmap_config veml3235_regmap_config = {
+ .name = "veml3235_regmap",
+ .reg_bits = 8,
+ .val_bits = 16,
+ .max_register = VEML3235_REG_ID,
+ .val_format_endian = REGMAP_ENDIAN_LITTLE,
+};
+
+static int veml3235_get_it(struct veml3235_data *data, int *val, int *val2)
+{
+ int ret, reg;
+
+ ret = regmap_field_read(data->rf.it, ®);
+ if (ret)
+ return ret;
+
+ switch (reg) {
+ case 0:
+ *val2 = 50000;
+ break;
+ case 1:
+ *val2 = 100000;
+ break;
+ case 2:
+ *val2 = 200000;
+ break;
+ case 3:
+ *val2 = 400000;
+ break;
+ case 4:
+ *val2 = 800000;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ *val = 0;
+
+ return IIO_VAL_INT_PLUS_MICRO;
+}
+
+static int veml3235_set_it(struct iio_dev *indio_dev, int val, int val2)
+{
+ struct veml3235_data *data = iio_priv(indio_dev);
+ int ret, new_it, it_idx;
+
+ if (val)
+ return -EINVAL;
+
+ switch (val2) {
+ case 50000:
+ new_it = 0x00;
+ it_idx = 4;
+ break;
+ case 100000:
+ new_it = 0x01;
+ it_idx = 3;
+ break;
+ case 200000:
+ new_it = 0x02;
+ it_idx = 2;
+ break;
+ case 400000:
+ new_it = 0x03;
+ it_idx = 1;
+ break;
+ case 800000:
+ new_it = 0x04;
+ it_idx = 0;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ ret = regmap_field_write(data->rf.it, new_it);
+ if (ret) {
+ dev_err(data->dev,
+ "failed to update integration time: %d\n", ret);
+ return ret;
+ }
+
+ if (data->it < it_idx)
+ data->resolution <<= it_idx - data->it;
+ else if (data->it > it_idx)
+ data->resolution >>= data->it - it_idx;
+
+ data->it = it_idx;
+
+ return 0;
+}
+
+static int veml3235_set_gain(struct iio_dev *indio_dev, int val, int val2)
+{
+ struct veml3235_data *data = iio_priv(indio_dev);
+ int ret, new_gain, gain_idx;
+
+ if (val2 != 0)
+ return -EINVAL;
+
+ switch (val) {
+ case 1:
+ new_gain = 0x00;
+ gain_idx = 3;
+ break;
+ case 2:
+ new_gain = 0x01;
+ gain_idx = 2;
+ break;
+ case 4:
+ new_gain = 0x03;
+ gain_idx = 1;
+ break;
+ case 8:
+ new_gain = 0x07;
+ gain_idx = 0;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ ret = regmap_field_write(data->rf.gain, new_gain);
+ if (ret) {
+ dev_err(data->dev, "failed to set gain: %d\n", ret);
+ return ret;
+ }
+
+ if (data->gain < gain_idx)
+ data->resolution <<= gain_idx - data->gain;
+ else if (data->gain > gain_idx)
+ data->resolution >>= data->gain - gain_idx;
+
+ data->gain = gain_idx;
+
+ return 0;
+}
+
+static int veml3235_get_gain(struct veml3235_data *data, int *val)
+{
+ int ret, reg;
+
+ ret = regmap_field_read(data->rf.gain, ®);
+ if (ret) {
+ dev_err(data->dev, "failed to read gain %d\n", ret);
+ return ret;
+ }
+
+ switch (reg & 0x03) {
+ case 0:
+ *val = 1;
+ break;
+ case 1:
+ *val = 2;
+ break;
+ case 3:
+ *val = 4;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ /* Double gain */
+ if (reg & 0x04)
+ *val *= 2;
+
+ return IIO_VAL_INT;
+}
+
+static int veml3235_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val,
+ int *val2, long mask)
+{
+ struct veml3235_data *data = iio_priv(indio_dev);
+ struct regmap *regmap = data->regmap;
+ int ret, reg;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ case IIO_CHAN_INFO_PROCESSED:
+ switch (chan->type) {
+ case IIO_LIGHT:
+ ret = regmap_read(regmap, VEML3235_REG_ALS_DATA, ®);
+ if (ret < 0)
+ return ret;
+
+ if (mask == IIO_CHAN_INFO_PROCESSED) {
+ *val = (reg * data->resolution) / 100000;
+ *val2 = (reg * data->resolution) % 100000 * 10;
+ return IIO_VAL_INT_PLUS_MICRO;
+ }
+ *val = reg;
+ return IIO_VAL_INT;
+ case IIO_INTENSITY:
+ ret = regmap_read(regmap, VEML3235_REG_WH_DATA, ®);
+ if (ret < 0)
+ return ret;
+
+ *val = reg;
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+ case IIO_CHAN_INFO_INT_TIME:
+ return veml3235_get_it(data, val, val2);
+ case IIO_CHAN_INFO_SCALE:
+ return veml3235_get_gain(data, val);
+ default:
+ return -EINVAL;
+ }
+}
+
+static int veml3235_read_avail(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ const int **vals, int *type, int *length,
+ long mask)
+{
+ switch (mask) {
+ case IIO_CHAN_INFO_INT_TIME:
+ *vals = (int *)&veml3235_it_times;
+ *length = 2 * ARRAY_SIZE(veml3235_it_times);
+ *type = IIO_VAL_INT_PLUS_MICRO;
+ return IIO_AVAIL_LIST;
+ case IIO_CHAN_INFO_SCALE:
+ *vals = (int *)&veml3235_scale_vals;
+ *length = ARRAY_SIZE(veml3235_scale_vals);
+ *type = IIO_VAL_INT;
+ return IIO_AVAIL_LIST;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int veml3235_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ switch (mask) {
+ case IIO_CHAN_INFO_INT_TIME:
+ return veml3235_set_it(indio_dev, val, val2);
+ case IIO_CHAN_INFO_SCALE:
+ return veml3235_set_gain(indio_dev, val, val2);
+ }
+
+ return -EINVAL;
+}
+
+static void veml3235_read_id(struct veml3235_data *data)
+{
+ int ret, reg;
+
+ ret = regmap_field_read(data->rf.id, ®);
+ if (ret) {
+ dev_info(data->dev, "failed to read ID\n");
+ return;
+ }
+
+ if (reg != 0x35)
+ dev_info(data->dev, "Unknown ID %d\n", reg);
+}
+
+static const struct reg_field veml3235_rf_it =
+ REG_FIELD(VEML3235_REG_CONF, 4, 6);
+
+static const struct reg_field veml3235_rf_gain =
+ REG_FIELD(VEML3235_REG_CONF, 11, 13);
+
+static const struct reg_field veml3235_rf_id =
+ REG_FIELD(VEML3235_REG_ID, 0, 7);
+
+static int veml3235_regfield_init(struct veml3235_data *data)
+{
+ struct regmap *regmap = data->regmap;
+ struct device *dev = data->dev;
+ struct regmap_field *rm_field;
+ struct veml3235_rf *rf = &data->rf;
+
+ rm_field = devm_regmap_field_alloc(dev, regmap, veml3235_rf_it);
+ if (IS_ERR(rm_field))
+ return PTR_ERR(rm_field);
+ rf->it = rm_field;
+
+ rm_field = devm_regmap_field_alloc(dev, regmap, veml3235_rf_gain);
+ if (IS_ERR(rm_field))
+ return PTR_ERR(rm_field);
+ rf->gain = rm_field;
+
+ rm_field = devm_regmap_field_alloc(dev, regmap, veml3235_rf_id);
+ if (IS_ERR(rm_field))
+ return PTR_ERR(rm_field);
+ rf->id = rm_field;
+
+ return 0;
+}
+
+static int veml3235_hw_init(struct iio_dev *indio_dev)
+{
+ struct veml3235_data *data = iio_priv(indio_dev);
+ struct device *dev = data->dev;
+ int ret;
+
+ ret = regmap_write(data->regmap, VEML3235_REG_CONF, 0x1001);
+ if (ret)
+ return dev_err_probe(dev, ret, "failed to set configuration\n");
+
+ /*
+ * Set gain to 1, integration time to 100 ms, and the resulting
+ * resolution in (lux/cnt * 100000) according to the typical value
+ * from the datasheet.
+ */
+ ret = regmap_field_write(data->rf.gain, 0x00);
+ if (ret)
+ return dev_err_probe(data->dev, ret, "failed to set gain\n");
+
+ ret = regmap_field_write(data->rf.it, 0x01);
+ if (ret)
+ return dev_err_probe(data->dev, ret,
+ "failed to set integration time\n");
+
+ data->gain = 3;
+ data->it = 3;
+ data->resolution = 13632;
+
+ ret = veml3235_power_on(data);
+ if (ret)
+ return dev_err_probe(dev, ret, "failed to power on\n");
+
+ return devm_add_action_or_reset(dev, veml3235_shut_down_action, data);
+}
+
+static const struct iio_info veml3235_info = {
+ .read_raw = veml3235_read_raw,
+ .read_avail = veml3235_read_avail,
+ .write_raw = veml3235_write_raw,
+};
+
+static int veml3235_probe(struct i2c_client *client)
+{
+ struct device *dev = &client->dev;
+ struct veml3235_data *data;
+ struct iio_dev *indio_dev;
+ struct regmap *regmap;
+ int ret;
+
+ regmap = devm_regmap_init_i2c(client, &veml3235_regmap_config);
+ if (IS_ERR(regmap))
+ return dev_err_probe(dev, PTR_ERR(regmap),
+ "failed to setup regmap\n");
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ data = iio_priv(indio_dev);
+ i2c_set_clientdata(client, indio_dev);
+ data->client = client;
+ data->dev = dev;
+ data->regmap = regmap;
+
+ ret = veml3235_regfield_init(data);
+ if (ret)
+ return dev_err_probe(dev, ret, "failed to init regfield\n");
+
+ ret = devm_regulator_get_enable(dev, "vdd");
+ if (ret)
+ return dev_err_probe(dev, ret, "failed to enable regulator\n");
+
+ indio_dev->name = "veml3235";
+ indio_dev->channels = veml3235_channels;
+ indio_dev->num_channels = ARRAY_SIZE(veml3235_channels);
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->info = &veml3235_info;
+
+ veml3235_read_id(data);
+
+ ret = veml3235_hw_init(indio_dev);
+ if (ret < 0)
+ return ret;
+
+ return devm_iio_device_register(dev, indio_dev);
+}
+
+static int veml3235_runtime_suspend(struct device *dev)
+{
+ struct veml3235_data *data = iio_priv(dev_get_drvdata(dev));
+ int ret;
+
+ ret = veml3235_shut_down(data);
+ if (ret < 0)
+ dev_err(data->dev, "failed to suspend: %d\n", ret);
+
+ return ret;
+}
+
+static int veml3235_runtime_resume(struct device *dev)
+{
+ struct veml3235_data *data = iio_priv(dev_get_drvdata(dev));
+ int ret;
+
+ ret = veml3235_power_on(data);
+ if (ret < 0)
+ dev_err(data->dev, "failed to resume: %d\n", ret);
+
+ return ret;
+}
+
+static DEFINE_RUNTIME_DEV_PM_OPS(veml3235_pm_ops, veml3235_runtime_suspend,
+ veml3235_runtime_resume, NULL);
+
+static const struct of_device_id veml3235_of_match[] = {
+ { .compatible = "vishay,veml3235" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, veml3235_of_match);
+
+static const struct i2c_device_id veml3235_id[] = {
+ { "veml3235" },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, veml3235_id);
+
+static struct i2c_driver veml3235_driver = {
+ .driver = {
+ .name = "veml3235",
+ .of_match_table = veml3235_of_match,
+ .pm = pm_ptr(&veml3235_pm_ops),
+ },
+ .probe = veml3235_probe,
+ .id_table = veml3235_id,
+};
+module_i2c_driver(veml3235_driver);
+
+MODULE_AUTHOR("Javier Carrasco <javier.carrasco.cruz@gmail.com>");
+MODULE_DESCRIPTION("VEML3235 Ambient Light Sensor");
+MODULE_LICENSE("GPL");
--
2.43.0On Sun, 20 Oct 2024 21:12:17 +0200
Javier Carrasco <javier.carrasco.cruz@gmail.com> wrote:
> The Vishay veml3235 is a low-power ambient light sensor with I2C
> interface. It provides a minimum detectable intensity of
> 0.0021 lx/cnt, configurable integration time and gain, and an additional
> white channel to distinguish between different light sources.
>
> Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Hi Javier,
I missed one thing on previous review...
There is no obvious reason this driver needs to provide raw and processed
values. Unless I'm missing something, just provide raw and let userspace
do the maths for us.
Jonathan
> diff --git a/drivers/iio/light/veml3235.c b/drivers/iio/light/veml3235.c
> new file mode 100644
> index 000000000000..fa2141cced8f
> --- /dev/null
> +++ b/drivers/iio/light/veml3235.c
> +static const struct iio_chan_spec veml3235_channels[] = {
> + {
> + .type = IIO_LIGHT,
> + .channel = CH_ALS,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> + BIT(IIO_CHAN_INFO_PROCESSED),
Why both raw + scale and processed?
We normally only provide raw and processed for light sensors if:
1) The conversion is non linear and hard to reverse.
2) There are events that are thresholds on the raw value.
Here it is linear so just provide _RAW.
> + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME) |
> + BIT(IIO_CHAN_INFO_SCALE),
> + .info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME) |
> + BIT(IIO_CHAN_INFO_SCALE),
> + },
> + {
> + .type = IIO_INTENSITY,
> + .channel = CH_WHITE,
> + .modified = 1,
> + .channel2 = IIO_MOD_LIGHT_BOTH,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME) |
> + BIT(IIO_CHAN_INFO_SCALE),
> + .info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME) |
> + BIT(IIO_CHAN_INFO_SCALE),
> + },
> +};
On 21/10/2024 20:39, Jonathan Cameron wrote: > On Sun, 20 Oct 2024 21:12:17 +0200 > Javier Carrasco <javier.carrasco.cruz@gmail.com> wrote: > >> The Vishay veml3235 is a low-power ambient light sensor with I2C >> interface. It provides a minimum detectable intensity of >> 0.0021 lx/cnt, configurable integration time and gain, and an additional >> white channel to distinguish between different light sources. >> >> Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com> > Hi Javier, > > I missed one thing on previous review... > There is no obvious reason this driver needs to provide raw and processed > values. Unless I'm missing something, just provide raw and let userspace > do the maths for us. > > Jonathan > Sure, I will drop that for v3. I added it because this driver took the veml6030 as a reference, and that driver provides the processed value. I guess that the veml6030 should have not provided processed values either, but it's late to remove them after the driver was released. Now that we are at it, what is the rule (of thumb?) to provide processed values? Those that can't be obtained from the raw data and simple operations with the scale/offset/integration time/whatever userspace can see? Thank you and best regards, Javier Carrasco
On Mon, 21 Oct 2024 22:21:22 +0200 Javier Carrasco <javier.carrasco.cruz@gmail.com> wrote: > On 21/10/2024 20:39, Jonathan Cameron wrote: > > On Sun, 20 Oct 2024 21:12:17 +0200 > > Javier Carrasco <javier.carrasco.cruz@gmail.com> wrote: > > > >> The Vishay veml3235 is a low-power ambient light sensor with I2C > >> interface. It provides a minimum detectable intensity of > >> 0.0021 lx/cnt, configurable integration time and gain, and an additional > >> white channel to distinguish between different light sources. > >> > >> Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com> > > Hi Javier, > > > > I missed one thing on previous review... > > There is no obvious reason this driver needs to provide raw and processed > > values. Unless I'm missing something, just provide raw and let userspace > > do the maths for us. > > > > Jonathan > > > Sure, I will drop that for v3. I added it because this driver took the > veml6030 as a reference, and that driver provides the processed value. I > guess that the veml6030 should have not provided processed values > either, but it's late to remove them after the driver was released. > > Now that we are at it, what is the rule (of thumb?) to provide processed > values? Those that can't be obtained from the raw data and simple > operations with the scale/offset/integration time/whatever userspace can > see? Yes. If the conversion is linear, then leave it to userspace (with scale and offset provided). If it's not linear then in kernel because currently we have no other choice. There are some historical quirks where a processed only interface got in then we had to add raw later (typically when we added buffered output where scale and offset are important because processed values normally don't pack well). Jonathan > > Thank you and best regards, > Javier Carrasco
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