On Sun, Feb 19, 2017 at 04:00:41PM +0000, Jonathan Cameron wrote: > On 19/02/17 15:04, Jonathan Cameron wrote: > > On 19/02/17 14:58, Tomasz Duszynski wrote: > >> Add sht21 relative humidity and temperature sensor driver. There already > >> exists an in-kernel driver under hwmon but with limited functionality > >> like humidity and temperature always measured together at predefined > >> resolutions, etc. > >> > >> New iio driver comes without limitations of predecessor, uses non-blocking i2c > >> communication mode and adds triggered buffer support thus is suited for more > >> use cases. > >> > >> Device datasheet can be found under: > >> > >> https://www.sensirion.com/fileadmin/user_upload/customers/sensirion/ \ > >> Dokumente/2_Humidity_Sensors/Sensirion_Humidity_Sensors_SHT21_Datasheet_V4.pdf > >> > >> Signed-off-by: Tomasz Duszynski <tduszyns@xxxxxxxxx> > > Hi Tomasz, > > > > I haven't looked at this yet, but one thing we have to do whenever suggesting > > replacement of an hwmon driver is to convince the hwmon guys that it is a > > good idea. > > > > As such I've cc'd Guenter, Jean and the list. > > > > Jonathan > > > > p.s Probably won't get to this today as running out of time. Depending on > > how mad the week is it might be next weekend before I get a chance. > Very quick review follows so as not to leave you without feedback. > > I may well have missed stuff though as did this in a few minutes... > > J > >> --- > >> drivers/iio/humidity/Kconfig | 10 + > >> drivers/iio/humidity/Makefile | 1 + > >> drivers/iio/humidity/sht21.c | 519 ++++++++++++++++++++++++++++++++++++++++++ > >> 3 files changed, 530 insertions(+) > >> create mode 100644 drivers/iio/humidity/sht21.c > >> > >> diff --git a/drivers/iio/humidity/Kconfig b/drivers/iio/humidity/Kconfig > >> index 866dda133336..93247ecc9324 100644 > >> --- a/drivers/iio/humidity/Kconfig > >> +++ b/drivers/iio/humidity/Kconfig > >> @@ -35,6 +35,16 @@ config HTU21 > >> This driver can also be built as a module. If so, the module will > >> be called htu21. > >> > >> +config SHT21 > >> + tristate "Sensirion SHT21 relative humidity and temperature sensor" > >> + depends on I2C > >> + help > >> + Say yes here to build support for the Sensirion SHT21 relative > >> + humidity and temperature sensor. > >> + > >> + To compile this driver as a module, choose M here: the module > >> + will be called sht21. > >> + > >> 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 c9f089a9a6b8..f2472fd2cc44 100644 > >> --- a/drivers/iio/humidity/Makefile > >> +++ b/drivers/iio/humidity/Makefile > >> @@ -5,5 +5,6 @@ > >> obj-$(CONFIG_DHT11) += dht11.o > >> obj-$(CONFIG_HDC100X) += hdc100x.o > >> obj-$(CONFIG_HTU21) += htu21.o > >> +obj-$(CONFIG_SHT21) += sht21.o > >> obj-$(CONFIG_SI7005) += si7005.o > >> obj-$(CONFIG_SI7020) += si7020.o > >> diff --git a/drivers/iio/humidity/sht21.c b/drivers/iio/humidity/sht21.c > >> new file mode 100644 > >> index 000000000000..199933b87297 > >> --- /dev/null > >> +++ b/drivers/iio/humidity/sht21.c > >> @@ -0,0 +1,519 @@ > >> +/* > >> + * Sensirion SHT21 relative humidity and temperature sensor driver > >> + * > >> + * Copyright (C) 2017 Tomasz Duszynski <tduszyns@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. > >> + * > >> + * 7-bit I2C slave address: 0x40 > >> + */ > >> + > >> +#include <linux/bitops.h> > >> +#include <linux/delay.h> > >> +#include <linux/i2c.h> > >> +#include <linux/iio/buffer.h> > >> +#include <linux/iio/iio.h> > >> +#include <linux/iio/sysfs.h> > >> +#include <linux/iio/trigger_consumer.h> > >> +#include <linux/iio/triggered_buffer.h> > >> +#include <linux/module.h> > >> +#include <linux/mutex.h> > >> +#include <linux/of.h> > >> + > >> +#define SHT21_DRV_NAME "sht21" > >> + > >> +#define SHT21_TRIGGER_T_MEASUREMENT 0xF3 > >> +#define SHT21_TRIGGER_RH_MEASUREMENT 0xF5 > >> + > >> +#define SHT21_WRITE_USER_REG 0xE6 > >> +#define SHT21_READ_USER_REG 0xE7 > >> +#define SHT21_SOFT_RESET 0xFE > >> + > >> +#define SHT21_USER_REG_RES_8_12 BIT(0) > >> +#define SHT21_USER_REG_RES_10_13 BIT(7) > >> +#define SHT21_USER_REG_RES_11_11 (BIT(7) | BIT(0)) > >> + > >> +#define SHT21_USER_REG_ENABLE_HEATER BIT(2) > >> + > >> +enum { > >> + RES_12_14, > >> + RES_8_12, > >> + RES_10_13, > >> + RES_11_11, > >> +}; > >> + > >> +/* > >> + * Combined sampling frequency i.e measuring RH and T together, which seems > >> + * to be common case for pressure/humidity sensors, was chosen so that sensor > >> + * is active for only 10% of time thus avoiding self-heating effect. > >> + * > >> + * Note that sampling frequencies are higher when measuring RH or T separately. > >> + * > >> + * Following table shows how available resolutions, combined sampling frequency > >> + * and frequencies for RH and T when measured separately are related. > >> + * > >> + * +-------------------+-------------+---------+--------+ > >> + * | RH / T resolution | RH + T [Hz] | RH [Hz] | T [Hz] | > >> + * +-------------------+-------------+---------+--------+ > >> + * | 12 / 14 | 0.88 | 3.45 | 1.18 | > >> + * +-------------------+-------------+---------+--------+ > >> + * | 8 / 12 | 3.85 | 25 | 4.55 | > >> + * +-------------------+-------------+---------+--------+ > >> + * | 10 / 13 | 1.93 | 11.11 | 2.33 | > >> + * +-------------------+-------------+---------+--------+ > >> + * | 11 / 11 | 2.28 | 6.67 | 9.09 | > >> + * +-------------------+-------------+---------+--------+ > >> + */ > >> +static const struct { > >> + int freq; > >> + int freq2; > >> + > >> + int rh_meas_time; > >> + int t_meas_time; > >> +} sht21_freq_meas_time_tbl[] = { > >> + [RES_12_14] = { 0, 880000, 29000, 85000 }, > >> + [RES_8_12] = { 3, 850000, 4000, 22000 }, > >> + [RES_10_13] = { 1, 930000, 9000, 43000 }, > >> + [RES_11_11] = { 2, 280000, 15000, 11000 } > >> +}; > >> + > >> +struct sht21_state { > >> + struct i2c_client *client; > >> + struct mutex lock; > >> + int res; > >> +}; > >> + > >> +static int sht21_verify_crc(const u8 *data, int len) > >> +{ > >> + int i, j; > >> + u8 crc = 0; > >> + > >> + for (i = 0; i < len; i++) { > >> + crc ^= data[i]; > >> + > >> + for (j = 0; j < 8; j++) { > >> + if (crc & 0x80) > >> + crc = (crc << 1) ^ 0x31; > >> + else > >> + crc = crc << 1; > >> + } > >> + } > >> + > >> + return crc == 0; > >> +} > >> + > >> +/* every chunk of data read from sensor has crc byte appended */ > >> +static int sht21_read_data(struct sht21_state *state, int cmd, int *data) > >> +{ > >> + int delay, ret = 0; > >> + __be32 tmp = 0; > >> + > >> + switch (cmd) { > >> + case SHT21_READ_USER_REG: > >> + ret = i2c_smbus_read_i2c_block_data(state->client, cmd, > >> + 2, (u8 *)&tmp); > >> + break; > >> + case SHT21_TRIGGER_RH_MEASUREMENT: > >> + case SHT21_TRIGGER_T_MEASUREMENT: > >> + ret = i2c_smbus_write_byte(state->client, cmd); > >> + if (ret) > >> + break; > >> + > >> + delay = cmd == SHT21_TRIGGER_RH_MEASUREMENT ? > >> + sht21_freq_meas_time_tbl[state->res].rh_meas_time : > >> + sht21_freq_meas_time_tbl[state->res].t_meas_time; > >> + > >> + usleep_range(delay, delay + 1000); > >> + > >> + ret = i2c_master_recv(state->client, (u8 *)&tmp, 3); > >> + if (ret < 0) > >> + break; > >> + > >> + /* > >> + * Sensor should not be active more that 10% of time > >> + * otherwise it heats up and returns biased measurements. > >> + */ > >> + delay *= 9; > >> + usleep_range(delay, delay + 1000); > >> + > >> + break; > >> + } > >> + > >> + if (ret < 0) > >> + return ret; > >> + > >> + if (!sht21_verify_crc((u8 *)&tmp, ret)) { > >> + dev_err(&state->client->dev, "Data integrity check failed\n"); > >> + return -EINVAL; > >> + } > >> + > >> + /* crc byte no longer needed so drop it here */ > >> + *data = be32_to_cpu(tmp) >> ((sizeof(tmp) - ret + 1) * 8); > >> + > >> + return 0; > >> +} > >> + > >> +static int sht21_write_data(struct sht21_state *state, int cmd, int *data) > >> +{ > >> + int ret; > No point in wrapping these two up. Just use the functions where they > are relevant directly. This just makes the code harder to follow. Ack > >> + > >> + if (!data) > >> + ret = i2c_smbus_write_byte(state->client, cmd); > >> + else > >> + ret = i2c_smbus_write_byte_data(state->client, cmd, *data); > >> + > >> + return ret; > >> +} > >> + > >> +static int sht21_trigger_measurement(struct sht21_state *state, int cmd, int *data) > >> +{ > >> + int ret; > >> + > >> + mutex_lock(&state->lock); > >> + ret = sht21_read_data(state, cmd, data); > >> + if (ret) { > >> + mutex_unlock(&state->lock); > >> + return ret; > >> + } > >> + mutex_unlock(&state->lock); > >> + > >> + return 0; > >> +} > >> + > >> +static int sht21_trigger_rh_measurement(struct sht21_state *state, int *data) > >> +{ > This is doing more than just triggering the measurement. The naming should reflect > that. Ack > >> + int ret = sht21_trigger_measurement(state, SHT21_TRIGGER_RH_MEASUREMENT, data); > >> + if (ret) > >> + return ret; > >> + > >> + *data >>= 2; > >> + *data = (((s64)*data * 125000) >> 14) - 6000; > >> + > >> + return 0; > >> +} > >> + > >> +static int sht21_trigger_t_measurement(struct sht21_state *state, int *data) > >> +{ > >> + int ret = sht21_trigger_measurement(state, SHT21_TRIGGER_T_MEASUREMENT, data); > >> + if (ret) > >> + return ret; > >> + > >> + *data >>= 2; > >> + *data = (((s64)*data * 175720) >> 14) - 46850; > >> + > >> + return 0; > >> +} > >> + > >> +static int sht21_set_resolution(struct sht21_state *state, int res) > >> +{ > >> + int ret, data; > >> + > >> + ret = sht21_read_data(state, SHT21_READ_USER_REG, &data); > >> + if (ret) > >> + return ret; > >> + > >> + data &= ~SHT21_USER_REG_RES_11_11; > >> + > >> + switch (res) { > >> + case RES_12_14: > >> + break; > >> + case RES_8_12: > >> + data |= SHT21_USER_REG_RES_8_12; > >> + break; > >> + case RES_10_13: > >> + data |= SHT21_USER_REG_RES_10_13; > >> + break; > >> + case RES_11_11: > >> + data |= SHT21_USER_REG_RES_11_11; > >> + break; > >> + } > >> + > >> + ret = sht21_write_data(state, SHT21_WRITE_USER_REG, &data); > >> + if (ret) > >> + return ret; > >> + > >> + state->res = res; > >> + > >> + return 0; > >> +} > >> + > >> +static int sht21_soft_reset(struct sht21_state *state) > >> +{ > >> + int ret = sht21_write_data(state, SHT21_SOFT_RESET, NULL); > >> + if (ret) { > >> + dev_err(&state->client->dev, "Failed to reset device\n"); > >> + return ret; > >> + } > >> + > >> + msleep(15); > >> + > >> + return 0; > >> +} > >> + > >> +static irqreturn_t sht21_trigger_handler(int irq, void *p) > >> +{ > >> + struct iio_poll_func *pf = p; > >> + struct iio_dev *indio_dev = pf->indio_dev; > >> + struct sht21_state *state = iio_priv(indio_dev); > >> + int buf[4], ret, i, j = 0; > >> + > >> + for_each_set_bit(i, indio_dev->active_scan_mask, indio_dev->masklength) { > >> + ret = i == 0 ? sht21_trigger_rh_measurement(state, &buf[j++]) : > >> + sht21_trigger_t_measurement(state, &buf[j++]); > This is a for loop that really just obscures what is going on. I'd open code it. Ack > >> + if (ret) > >> + goto out; > >> + } > >> + > >> + iio_push_to_buffers_with_timestamp(indio_dev, buf, > >> + iio_get_time_ns(indio_dev)); > >> +out: > >> + iio_trigger_notify_done(indio_dev->trig); > >> + > >> + return IRQ_HANDLED; > >> +} > >> + > >> +static int sht21_read_raw(struct iio_dev *indio_dev, > >> + struct iio_chan_spec const *channel, int *val, > >> + int *val2, long mask) > >> +{ > >> + struct sht21_state *state = iio_priv(indio_dev); > >> + int ret; > >> + > >> + switch (mask) { > >> + case IIO_CHAN_INFO_PROCESSED: > >> + if (iio_buffer_enabled(indio_dev)) > >> + return -EBUSY; > You've randomly mixed checking this by hand and using > the claim_direct functions. Please use them everywhere. > They aren't race prone (which this is). Ah I see. Will fix that. > >> + > >> + switch (channel->type) { > >> + case IIO_HUMIDITYRELATIVE: > >> + ret = sht21_trigger_rh_measurement(state, val); > >> + if (ret) > >> + return ret; > >> + > >> + return IIO_VAL_INT; > >> + case IIO_TEMP: > >> + ret = sht21_trigger_t_measurement(state, val); > >> + if (ret) > >> + return ret; > >> + > >> + return IIO_VAL_INT; > >> + default: > >> + return -EINVAL; > >> + } > >> + case IIO_CHAN_INFO_SAMP_FREQ: > >> + *val = sht21_freq_meas_time_tbl[state->res].freq; > >> + *val2 = sht21_freq_meas_time_tbl[state->res].freq2; > >> + > >> + return IIO_VAL_INT_PLUS_MICRO; > >> + default: > >> + return -EINVAL; > >> + } > >> +} > >> + > >> +static int sht21_write_raw(struct iio_dev *indio_dev, > >> + struct iio_chan_spec const *chan, > >> + int val, int val2, long mask) > >> +{ > >> + struct sht21_state *state = iio_priv(indio_dev); > >> + int i, ret; > >> + > >> + switch (mask) { > >> + case IIO_CHAN_INFO_SAMP_FREQ: > >> + for (i = 0; i < ARRAY_SIZE(sht21_freq_meas_time_tbl); i++) > >> + if (val == sht21_freq_meas_time_tbl[i].freq && > >> + val2 == sht21_freq_meas_time_tbl[i].freq2) > >> + break; > >> + > >> + if (i == ARRAY_SIZE(sht21_freq_meas_time_tbl)) > >> + return -EINVAL; > >> + > >> + ret = iio_device_claim_direct_mode(indio_dev); > >> + if (ret) > >> + return ret; > >> + > >> + mutex_lock(&state->lock); > >> + ret = sht21_set_resolution(state, i); > >> + mutex_unlock(&state->lock); > >> + > >> + iio_device_release_direct_mode(indio_dev); > >> + > >> + return ret; > >> + default: > >> + return -EINVAL; > >> + } > >> +} > >> + > >> +static ssize_t sht21_show_heater(struct device *dev, > >> + struct device_attribute *attr, char *buf) > >> +{ > >> + struct iio_dev *indio_dev = dev_to_iio_dev(dev); > >> + struct sht21_state *state = iio_priv(indio_dev); > >> + int data, ret; > >> + > >> + ret = sht21_read_data(state, SHT21_READ_USER_REG, &data); > >> + if (ret) > >> + return ret; > >> + > >> + return sprintf(buf, "%d\n", !!(data & SHT21_USER_REG_ENABLE_HEATER)); > >> +} > >> + > >> +static ssize_t sht21_write_heater(struct device *dev, > >> + struct device_attribute *attr, > >> + const char *buf, size_t len) > >> +{ > >> + struct iio_dev *indio_dev = dev_to_iio_dev(dev); > >> + struct sht21_state *state = iio_priv(indio_dev); > >> + int val, data, ret; > >> + > >> + ret = kstrtoint(buf, 10, &val); > >> + if (ret) > >> + return ret; > >> + if (val != 0 && val != 1) > >> + return -EINVAL; > >> + > >> + mutex_lock(&state->lock); > >> + ret = sht21_read_data(state, SHT21_READ_USER_REG, &data); > >> + if (ret) { > >> + mutex_unlock(&state->lock); > >> + return ret; > >> + } > >> + > >> + if (val) > >> + data |= SHT21_USER_REG_ENABLE_HEATER; > >> + else > >> + data &= ~SHT21_USER_REG_ENABLE_HEATER; > >> + > >> + ret = sht21_write_data(state, SHT21_WRITE_USER_REG, &data); > >> + mutex_unlock(&state->lock); > >> + > >> + return ret ? ret : len; > >> +} > >> + > >> +static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("0.88 1.93 2.28 3.85"); > >> +static IIO_DEVICE_ATTR(heater_enable, S_IRUGO | S_IWUSR, > >> + sht21_show_heater, sht21_write_heater, 0); > >> + > >> +static struct attribute *sht21_attributes[] = { > >> + &iio_const_attr_sampling_frequency_available.dev_attr.attr, > >> + &iio_dev_attr_heater_enable.dev_attr.attr, > >> + NULL > >> +}; > >> + > >> +static const struct attribute_group sht21_attribute_group = { > >> + .attrs = sht21_attributes, > >> +}; > >> + > >> +static const struct iio_info sht21_info = { > >> + .driver_module = THIS_MODULE, > >> + .read_raw = sht21_read_raw, > >> + .write_raw = sht21_write_raw, > >> + .attrs = &sht21_attribute_group, > >> +}; > >> + > >> +#define SHT21_CHANNEL(_type, _index) { \ > >> + .type = _type, \ > >> + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \ > >> + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \ > >> + .scan_index = _index, \ > >> + .scan_type = { \ > >> + .sign = 's', \ > >> + .realbits = 32, \ > Really? does it provide true 32bit data? No. In fact less bits are used. Will change that to something more valid. > >> + .storagebits = 32, \ > >> + .endianness = IIO_CPU, \ > >> + }, \ > >> +} > >> + > >> +static const struct iio_chan_spec sht21_channels[] = { > >> + SHT21_CHANNEL(IIO_HUMIDITYRELATIVE, 0), > >> + SHT21_CHANNEL(IIO_TEMP, 1), > >> + IIO_CHAN_SOFT_TIMESTAMP(2), > >> +}; > >> + > >> +static int sht21_probe(struct i2c_client *client, const struct i2c_device_id *id) > >> +{ > >> + struct iio_dev *indio_dev; > >> + struct sht21_state *data; > >> + int ret; > >> + > >> + if (!i2c_check_functionality(client->adapter, > >> + I2C_FUNC_SMBUS_WRITE_BYTE | > >> + I2C_FUNC_SMBUS_BYTE_DATA | > >> + I2C_FUNC_SMBUS_READ_I2C_BLOCK)) > >> + 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 = id->name; > >> + indio_dev->modes = INDIO_DIRECT_MODE; > >> + indio_dev->info = &sht21_info; > >> + indio_dev->channels = sht21_channels; > >> + indio_dev->num_channels = ARRAY_SIZE(sht21_channels); > >> + > >> + ret = sht21_soft_reset(data); > >> + if (ret) > >> + return ret; > >> + > >> + ret = iio_triggered_buffer_setup(indio_dev, NULL, > >> + sht21_trigger_handler, NULL); > >> + if (ret) > >> + return ret; > >> + > >> + ret = iio_device_register(indio_dev); > >> + if (ret) > >> + iio_triggered_buffer_cleanup(indio_dev); > >> + > >> + return ret; > >> +} > >> + > >> +static int sht21_remove(struct i2c_client *client) > >> +{ > >> + struct iio_dev *indio_dev = i2c_get_clientdata(client); > >> + > >> + iio_device_unregister(indio_dev); > >> + iio_triggered_buffer_cleanup(indio_dev); > There are devm versions of both of the thing for the > two setup functions you are unwinding here. Use them > and you can drop the remove function entirely. Ack > >> + > >> + return 0; > >> +} > >> + > >> +static const struct i2c_device_id sht21_id[] = { > >> + { "sht21", 0 }, > >> + { } > >> +}; > >> +MODULE_DEVICE_TABLE(i2c, sht21_id); > >> + > >> +static const struct of_device_id sht21_of_match[] = { > >> + { .compatible = "sensirion,sht21" }, > >> + { } > >> +}; > >> +MODULE_DEVICE_TABLE(of, sht21_of_match); > >> + > >> +static struct i2c_driver sht21_driver = { > >> + .driver = { > >> + .name = SHT21_DRV_NAME, > >> + .of_match_table = of_match_ptr(sht21_of_match), > >> + }, > >> + .id_table = sht21_id, > >> + .probe = sht21_probe, > >> + .remove = sht21_remove, > >> +}; > >> +module_i2c_driver(sht21_driver); > >> + > >> +MODULE_DESCRIPTION("Sensirion SHT21 relative humidity and temperature sensor driver"); > >> +MODULE_AUTHOR("Tomasz Duszynski <tduszyns@xxxxxxxxx>"); > >> +MODULE_LICENSE("GPL v2"); > >> -- > >> 2.11.1 > >> > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-iio" in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > Thanks for review Jonathan! -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
