On Sat, Sep 5, 2015 at 9:40 AM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> 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?)
Yeah I'll make this more clear in v3.
>> +
>> + 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.
>
Ok will fix!
>> + 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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