On 02/09/15 04:58, Matt Ranostay wrote:
> Add support for the HDC100x temperature and humidity sensors
> including the resistive heater element.
>
> Signed-off-by: Matt Ranostay <mranostay@xxxxxxxxx>
Just a couple of corners of program flow that I think could be cleaned
up slightly (I'd have probably let it go as is, but we are very early
in the cycle, so might as well aim for perfection!)
Jonathan
> ---
> .../ABI/testing/sysfs-bus-iio-humidity-hdc100x | 9 +
> drivers/iio/humidity/Kconfig | 10 +
> drivers/iio/humidity/Makefile | 1 +
> drivers/iio/humidity/hdc100x.c | 317 +++++++++++++++++++++
> 4 files changed, 337 insertions(+)
> create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-humidity-hdc100x
> create mode 100644 drivers/iio/humidity/hdc100x.c
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-humidity-hdc100x b/Documentation/ABI/testing/sysfs-bus-iio-humidity-hdc100x
> new file mode 100644
> index 0000000..b72bb62
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-iio-humidity-hdc100x
> @@ -0,0 +1,9 @@
> +What: /sys/bus/iio/devices/iio:deviceX/out_current_heater_raw
> +What: /sys/bus/iio/devices/iio:deviceX/out_current_heater_raw_available
> +KernelVersion: 4.3
> +Contact: linux-iio@xxxxxxxxxxxxxxx
> +Description:
> + Controls the heater device within the humidity sensor to get
> + rid of excess condensation.
> +
> + Valid control values are 0 = OFF, and 1 = ON.
> diff --git a/drivers/iio/humidity/Kconfig b/drivers/iio/humidity/Kconfig
> index 688c0d1..353ee9a 100644
> --- a/drivers/iio/humidity/Kconfig
> +++ b/drivers/iio/humidity/Kconfig
> @@ -12,6 +12,16 @@ config DHT11
> Other sensors should work as well as long as they speak the
> same protocol.
>
> +config HDC100X
> + tristate "TI HDC100x relative humidity and temperature sensor"
> + depends on I2C
> + help
> + Say yes here to build support for the TI HDC100x series of
> + relative humidity and temperature sensors.
> +
> + To compile this driver as a module, choose M here: the module
> + will be called hdc100x.
> +
> config SI7005
> tristate "SI7005 relative humidity and temperature sensor"
> depends on I2C
> diff --git a/drivers/iio/humidity/Makefile b/drivers/iio/humidity/Makefile
> index 86e2d26..3e62c0a 100644
> --- a/drivers/iio/humidity/Makefile
> +++ b/drivers/iio/humidity/Makefile
> @@ -3,5 +3,6 @@
> #
>
> obj-$(CONFIG_DHT11) += dht11.o
> +obj-$(CONFIG_HDC100X) += hdc100x.o
> obj-$(CONFIG_SI7005) += si7005.o
> obj-$(CONFIG_SI7020) += si7020.o
> diff --git a/drivers/iio/humidity/hdc100x.c b/drivers/iio/humidity/hdc100x.c
> new file mode 100644
> index 0000000..591bd92
> --- /dev/null
> +++ b/drivers/iio/humidity/hdc100x.c
> @@ -0,0 +1,317 @@
> +/*
> + * hdc100x.c - Support for the TI HDC100x temperature + humidity sensors
> + *
> + * Copyright (C) 2015 Matt Ranostay <mranostay@xxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/i2c.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +
> +#define HDC100X_REG_TEMP 0x00
> +#define HDC100X_REG_HUMIDITY 0x01
> +
> +#define HDC100X_REG_CONFIG 0x02
> +#define HDC100X_REG_CONFIG_HEATER_EN BIT(13)
> +
> +struct hdc100x_data {
> + struct i2c_client *client;
> + struct mutex lock;
> + u16 config;
> +
> + /* integration time of the sensor */
> + int adc_int_us[2];
> +};
> +
> +/* integration time in us */
> +static const int hdc100x_int_time[][3] = {
> + { 6350, 3650, 0 }, /* IIO_TEMP channel*/
> + { 6500, 3850, 2500 }, /* IIO_HUMIDITYRELATIVE channel */
> +};
> +
> +/* HDC100X_REG_CONFIG shift and mask values */
> +static const struct {
> + int shift;
> + int mask;
> +} hdc100x_resolution_shift[2] = {
> + { /* IIO_TEMP channel */
> + .shift = 10,
> + .mask = 1
> + },
> + { /* IIO_HUMIDITYRELATIVE channel */
> + .shift = 8,
> + .mask = 2,
> + },
> +};
> +
> +static IIO_CONST_ATTR(temp_integration_time_available,
> + "0.00365 0.00635");
> +
> +static IIO_CONST_ATTR(humidityrelative_integration_time_available,
> + "0.0025 0.00385 0.0065");
> +
> +static IIO_CONST_ATTR(out_current_heater_raw_available,
> + "0 1");
> +
> +static struct attribute *hdc100x_attributes[] = {
> + &iio_const_attr_temp_integration_time_available.dev_attr.attr,
> + &iio_const_attr_humidityrelative_integration_time_available.dev_attr.attr,
> + &iio_const_attr_out_current_heater_raw_available.dev_attr.attr,
> + NULL
> +};
> +
> +static struct attribute_group hdc100x_attribute_group = {
> + .attrs = hdc100x_attributes,
> +};
> +
> +static const struct iio_chan_spec hdc100x_channels[] = {
> + {
> + .type = IIO_TEMP,
> + .address = HDC100X_REG_TEMP,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> + BIT(IIO_CHAN_INFO_SCALE) |
> + BIT(IIO_CHAN_INFO_INT_TIME) |
> + BIT(IIO_CHAN_INFO_OFFSET),
> + },
> + {
> + .type = IIO_HUMIDITYRELATIVE,
> + .address = HDC100X_REG_HUMIDITY,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> + BIT(IIO_CHAN_INFO_SCALE) |
> + BIT(IIO_CHAN_INFO_INT_TIME)
> + },
> + {
> + .type = IIO_CURRENT,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> + .extend_name = "heater",
> + .output = 1,
> + },
> +};
> +
> +static int hdc100x_update_config(struct hdc100x_data *data, int mask, int val)
> +{
> + int tmp = (~mask & data->config) | val;
> + int ret;
> +
> + ret = i2c_smbus_write_word_swapped(data->client,
> + HDC100X_REG_CONFIG, tmp);
> + if (!ret)
> + data->config = tmp;
> +
> + return ret;
> +}
> +
> +static int hdc100x_set_it_time(struct hdc100x_data *data, int chan, int val2)
> +{
> + int shift = hdc100x_resolution_shift[chan].shift;
> + int ret = -EINVAL;
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(hdc100x_int_time[chan]); i++) {
> + if (val2 && val2 == hdc100x_int_time[chan][i]) {
> + ret = hdc100x_update_config(data,
> + hdc100x_resolution_shift[chan].mask << shift,
> + i << shift);
> + if (!ret)
> + data->adc_int_us[chan] = val2;
> + break;
> + }
> + }
> +
> + return ret;
> +}
> +
> +static int hdc100x_get_measurement(struct hdc100x_data *data,
> + struct iio_chan_spec const *chan)
> +{
> + struct i2c_client *client = data->client;
> + int delay = data->adc_int_us[chan->address];
> + int ret;
> + int val;
> +
> + /* start measurement */
> + ret = i2c_smbus_write_byte(client, chan->address);
> + if (ret < 0) {
> + dev_err(&client->dev, "cannot start measurement");
> + return ret;
> + }
> +
> + /* wait for integration time to pass */
> + usleep_range(delay, delay + 1000);
> +
> + ret = i2c_smbus_read_byte(client);
> + if (ret < 0) {
> + dev_err(&client->dev, "cannot read high byte measurement");
> + return ret;
> + }
> + val = ret << 6;
> +
> + ret = i2c_smbus_read_byte(client);
> + if (ret < 0) {
> + dev_err(&client->dev, "cannot read low byte measurement");
> + return ret;
> + }
> + val |= ret >> 2;
If you can't use a read word here I'd like docs to say why (presumably
starts / stops are wrong for what the device expects?)
> +
> + return val;
> +}
> +
> +static int hdc100x_get_heater_status(struct hdc100x_data *data)
> +{
> + return !!(data->config & HDC100X_REG_CONFIG_HEATER_EN);
> +}
> +
> +static int hdc100x_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan, int *val,
> + int *val2, long mask)
> +{
> + struct hdc100x_data *data = iio_priv(indio_dev);
> + int ret = -EINVAL;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + mutex_lock(&data->lock);
> + if (chan->type == IIO_CURRENT) {
> + *val = hdc100x_get_heater_status(data);
> + ret = IIO_VAL_INT;
> + } else {
> + ret = hdc100x_get_measurement(data, chan);
> + if (ret >= 0) {
> + *val = ret;
> + ret = IIO_VAL_INT;
> + }
> + }
> + mutex_unlock(&data->lock);r
I'd return ret here to have consistency across different parts of
this function.
> + break;
> + case IIO_CHAN_INFO_INT_TIME:
> + *val = 0;
> + *val2 = data->adc_int_us[chan->address];
> + return IIO_VAL_INT_PLUS_MICRO;
> + case IIO_CHAN_INFO_SCALE:
> + if (chan->type == IIO_TEMP) {
> + *val = 165;
> + *val2 = 65536 >> 2;
return directly in both these cases.
> + ret = IIO_VAL_FRACTIONAL;
> + } else {
> + *val = 0;
> + *val2 = 10000;
> + ret = IIO_VAL_INT_PLUS_MICRO;
> + }
> + break;
> + case IIO_CHAN_INFO_OFFSET:
> + *val = -40;
> + return IIO_VAL_INT;
> + default:
return -EINVAL; and you can loose the outer parts of this function.
> + break;
> + }
> +
> + return ret;
> +}
> +
> +static int hdc100x_write_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int val, int val2, long mask)
> +{
> + struct hdc100x_data *data = iio_priv(indio_dev);
> + int ret = -EINVAL;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_INT_TIME:
> + if (val != 0)
> + return -EINVAL;
> +
> + mutex_lock(&data->lock);
> + ret = hdc100x_set_it_time(data, chan->address, val2);
> + mutex_unlock(&data->lock);
> + break;
> + case IIO_CHAN_INFO_RAW:
> + if (chan->type == IIO_CURRENT) {
> + if (val2 != 0)
> + return -EINVAL;
> +
> + mutex_lock(&data->lock);
> + ret = hdc100x_update_config(data,
> + HDC100X_REG_CONFIG_HEATER_EN,
> + val ? HDC100X_REG_CONFIG_HEATER_EN : 0);
> + mutex_unlock(&data->lock);
> + }
This return ret is different from the other case for no particular
reason. If it makes sense to return here, it makes sense there
as well.
I think I'd martinally prefer if you inverted the logic to
check if the channel isn't IIO_CURRENT and return -EINVAL directly
if it isn't. Drops a level of indentation. You could the use a default:
statement returning -EINVAL to drop the return below and seeing of a
default value for ret above. Makes for slightly longer but
simpler code.
> + return ret;
> + }
> +
> + return ret;
> +}
> +
> +static const struct iio_info hdc100x_info = {
> + .read_raw = hdc100x_read_raw,
> + .write_raw = hdc100x_write_raw,
> + .attrs = &hdc100x_attribute_group,
> + .driver_module = THIS_MODULE,
> +};
> +
> +static int hdc100x_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct iio_dev *indio_dev;
> + struct hdc100x_data *data;
> +
> + if (!i2c_check_functionality(client->adapter,
> + I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BYTE))
> + return -ENODEV;
> +
> + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
> + if (!indio_dev)
> + return -ENOMEM;
> +
> + data = iio_priv(indio_dev);
> + i2c_set_clientdata(client, indio_dev);
> + data->client = client;
> + mutex_init(&data->lock);
> +
> + indio_dev->dev.parent = &client->dev;
> + indio_dev->name = dev_name(&client->dev);
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->info = &hdc100x_info;
> +
> + indio_dev->channels = hdc100x_channels;
> + indio_dev->num_channels = ARRAY_SIZE(hdc100x_channels);
> +
> + /* be sure we are in a known state */
> + hdc100x_set_it_time(data, 0, hdc100x_int_time[0][0]);
> + hdc100x_set_it_time(data, 1, hdc100x_int_time[1][0]);
> +
> + return devm_iio_device_register(&client->dev, indio_dev);
> +}
> +
> +static const struct i2c_device_id hdc100x_id[] = {
> + { "hdc100x", 0 },
> + { }
> +};
> +MODULE_DEVICE_TABLE(i2c, hdc100x_id);
> +
> +static struct i2c_driver hdc100x_driver = {
> + .driver = {
> + .name = "hdc100x",
> + },
> + .probe = hdc100x_probe,
> + .id_table = hdc100x_id,
> +};
> +module_i2c_driver(hdc100x_driver);
> +
> +MODULE_AUTHOR("Matt Ranostay <mranostay@xxxxxxxxx>");
> +MODULE_DESCRIPTION("TI HDC100x humidity and temperature sensor driver");
> +MODULE_LICENSE("GPL");
>
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