Re: [PATCH v2] iio: humidity: hdc100x: add triggered buffer support for HDC100X

From: Alison Schofield
Date: Fri Jul 22 2016 - 11:17:25 EST

On Thu, Jul 21, 2016 at 10:31:46PM -0700, Alison Schofield wrote:
> Triggered buffer support uses the HDC100X's dual acquisition mode
> to read both humidity and temperature in one shot.
>
> Signed-off-by: Alison Schofield <amsfield22@xxxxxxxxx>
> Cc: Daniel Baluta <daniel.baluta@xxxxxxxxx>
> ---

Reviewing myself, changes coming in v3
- don't need to do that overwrite in handler.
.scan_index will be used to grab correct data from correct
position in buffer.
- rm unused #define HDC100X_ALL_CHANNEL_MASK
- what else?

> Changes in v2:
> Thanks for the review Peter
> - switched endianness from IIO_CPU to IIO_BE
> - use only one buffer in the handler
> - simplify selection of temp &/or humidity to push to buffer
>
> drivers/iio/humidity/Kconfig | 2 +
> drivers/iio/humidity/hdc100x.c | 135 +++++++++++++++++++++++++++++++++++++++--
> 2 files changed, 131 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/iio/humidity/Kconfig b/drivers/iio/humidity/Kconfig
> index 738a86d..4883ce1 100644
> --- a/drivers/iio/humidity/Kconfig
> +++ b/drivers/iio/humidity/Kconfig
> @@ -25,6 +25,8 @@ config DHT11
> config HDC100X
> tristate "TI HDC100x relative humidity and temperature sensor"
> depends on I2C
> + select IIO_BUFFER
> + select IIO_TRIGGERED_BUFFER
> help
> Say yes here to build support for the TI HDC100x series of
> relative humidity and temperature sensors.
> diff --git a/drivers/iio/humidity/hdc100x.c b/drivers/iio/humidity/hdc100x.c
> index a03832a..9f41bb5 100644
> --- a/drivers/iio/humidity/hdc100x.c
> +++ b/drivers/iio/humidity/hdc100x.c
> @@ -22,13 +22,19 @@
>
> #include <linux/iio/iio.h>
> #include <linux/iio/sysfs.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/iio/triggered_buffer.h>
>
> #define HDC100X_REG_TEMP 0x00
> #define HDC100X_REG_HUMIDITY 0x01
>
> #define HDC100X_REG_CONFIG 0x02
> +#define HDC100X_REG_CONFIG_ACQ_MODE BIT(12)
> #define HDC100X_REG_CONFIG_HEATER_EN BIT(13)
>
> +#define HDC100X_ALL_CHANNEL_MASK GENMASK(1, 0)
> +
> struct hdc100x_data {
> struct i2c_client *client;
> struct mutex lock;
> @@ -87,20 +93,36 @@ static const struct iio_chan_spec hdc100x_channels[] = {
> BIT(IIO_CHAN_INFO_SCALE) |
> BIT(IIO_CHAN_INFO_INT_TIME) |
> BIT(IIO_CHAN_INFO_OFFSET),
> + .scan_index = 0,
> + .scan_type = {
> + .sign = 's',
> + .realbits = 16,
> + .storagebits = 16,
> + .endianness = IIO_BE,
> + },
> },
> {
> .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)
> + BIT(IIO_CHAN_INFO_INT_TIME),
> + .scan_index = 1,
> + .scan_type = {
> + .sign = 'u',
> + .realbits = 16,
> + .storagebits = 16,
> + .endianness = IIO_BE,
> + },
> },
> {
> .type = IIO_CURRENT,
> .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> .extend_name = "heater",
> .output = 1,
> + .scan_index = -1,
> },
> + IIO_CHAN_SOFT_TIMESTAMP(3),
> };
>
> static int hdc100x_update_config(struct hdc100x_data *data, int mask, int val)
> @@ -191,18 +213,21 @@ static int hdc100x_read_raw(struct iio_dev *indio_dev,
> case IIO_CHAN_INFO_RAW: {
> int ret;
>
> - mutex_lock(&data->lock);
> if (chan->type == IIO_CURRENT) {
> *val = hdc100x_get_heater_status(data);
> ret = IIO_VAL_INT;
> } else {
> + ret = iio_device_claim_direct_mode(indio_dev);
> + if (ret)
> + return ret;
> +
> ret = hdc100x_get_measurement(data, chan);
> + iio_device_release_direct_mode(indio_dev);
> if (ret >= 0) {
> *val = ret;
> ret = IIO_VAL_INT;
> }
> }
> - mutex_unlock(&data->lock);
> return ret;
> }
> case IIO_CHAN_INFO_INT_TIME:
> @@ -259,6 +284,80 @@ static int hdc100x_write_raw(struct iio_dev *indio_dev,
> }
> }
>
> +static int hdc100x_buffer_postenable(struct iio_dev *indio_dev)
> +{
> + struct hdc100x_data *data = iio_priv(indio_dev);
> + int ret;
> +
> + /* Buffer is enabled. First set ACQ Mode, then attach poll func */
> + mutex_lock(&data->lock);
> + ret = hdc100x_update_config(data, HDC100X_REG_CONFIG_ACQ_MODE,
> + HDC100X_REG_CONFIG_ACQ_MODE);
> + mutex_unlock(&data->lock);
> + if (ret)
> + return ret;
> +
> + return iio_triggered_buffer_postenable(indio_dev);
> +}
> +
> +static int hdc100x_buffer_predisable(struct iio_dev *indio_dev)
> +{
> + struct hdc100x_data *data = iio_priv(indio_dev);
> + int ret;
> +
> + /* First detach poll func, then reset ACQ mode. OK to disable buffer */
> + ret = iio_triggered_buffer_predisable(indio_dev);
> + if (ret)
> + return ret;
> +
> + mutex_lock(&data->lock);
> + ret = hdc100x_update_config(data, HDC100X_REG_CONFIG_ACQ_MODE, 0);
> + mutex_unlock(&data->lock);
> + return ret;
> +}
> +
> +static const struct iio_buffer_setup_ops hdc_buffer_setup_ops = {
> + .preenable = NULL,
> + .postenable = hdc100x_buffer_postenable,
> + .predisable = hdc100x_buffer_predisable,
> + .postdisable = NULL,
> +};
> +
> +static irqreturn_t hdc100x_trigger_handler(int irq, void *p)
> +{
> + struct iio_poll_func *pf = p;
> + struct iio_dev *indio_dev = pf->indio_dev;
> + struct hdc100x_data *data = iio_priv(indio_dev);
> + struct i2c_client *client = data->client;
> + int delay = data->adc_int_us[0] + data->adc_int_us[1];
> + int ret;
> + s16 buf[8]; /* 2x s16 + padding + 8 byte timestamp */
> +
> + /* dual read starts at temp register */
> + ret = i2c_smbus_write_byte(client, HDC100X_REG_TEMP);
> + if (ret < 0) {
> + dev_err(&client->dev, "cannot start measurement\n");
> + goto err;
> + }
> + usleep_range(delay, delay + 1000);
> +
> + ret = i2c_master_recv(client, (u8 *)buf, 4);
> + if (ret < 0) {
> + dev_err(&client->dev, "cannot read sensor data\n");
> + goto err;
> + }
> + /* overwrite unwanted temp data with humid data */
> + if (!test_bit(0, indio_dev->active_scan_mask))
> + buf[0] = buf[1];
don't need to do this. humid data will be plucked from it's position
defined in .scan_index.

> +
> + iio_push_to_buffers_with_timestamp(indio_dev, buf,
> + iio_get_time_ns(indio_dev));
> +err:
> + iio_trigger_notify_done(indio_dev->trig);
> +
> + return IRQ_HANDLED;
> +}
> +
> static const struct iio_info hdc100x_info = {
> .read_raw = hdc100x_read_raw,
> .write_raw = hdc100x_write_raw,
> @@ -271,9 +370,10 @@ static int hdc100x_probe(struct i2c_client *client,
> {
> struct iio_dev *indio_dev;
> struct hdc100x_data *data;
> + int ret;
>
> - if (!i2c_check_functionality(client->adapter,
> - I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BYTE))
> + if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA |
> + I2C_FUNC_SMBUS_BYTE | I2C_FUNC_I2C))
> return -EOPNOTSUPP;
>
> indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
> @@ -296,8 +396,30 @@ static int hdc100x_probe(struct i2c_client *client,
> /* 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]);
> + hdc100x_update_config(data, HDC100X_REG_CONFIG_ACQ_MODE, 0);
> +
> + ret = iio_triggered_buffer_setup(indio_dev, NULL,
> + hdc100x_trigger_handler,
> + &hdc_buffer_setup_ops);
> + if (ret < 0) {
> + dev_err(&client->dev, "iio triggered buffer setup failed\n");
> + return ret;
> + }
> + ret = iio_device_register(indio_dev);
> + if (ret < 0)
> + iio_triggered_buffer_cleanup(indio_dev);
> +
> + return ret;
> +}
> +
> +static int hdc100x_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);
>
> - return devm_iio_device_register(&client->dev, indio_dev);
> + return 0;
> }
>
> static const struct i2c_device_id hdc100x_id[] = {
> @@ -311,6 +433,7 @@ static struct i2c_driver hdc100x_driver = {
> .name = "hdc100x",
> },
> .probe = hdc100x_probe,
> + .remove = hdc100x_remove,
> .id_table = hdc100x_id,
> };
> module_i2c_driver(hdc100x_driver);
> --
> 2.1.4
>