Re: [PATCH v4] iio: humidity: hdc100x: add triggered buffer support for HDC100X

[Jonathan Cameron]

On 02/09/16 18:23, Alison Schofield wrote:
> Triggered buffer support uses the HDC100X's dual acquisition mode
> to read both humidity and temperature in one shot.
> 
> This patch depends on
> 	447136effbf4 ("iio: humidity: hdc100x: fix sensor data reads of
> 		       temp and humidity")
> 
> Signed-off-by: Alison Schofield <amsfield22@xxxxxxxxx>
> Cc: Daniel Baluta <daniel.baluta@xxxxxxxxx>
Looks good.  I'll have to hold it until the dependency has worked it's way
into my togreg branch in a week or so.

Feel free to remind me!

Jonathan
> ---
> 
> Changes in v4:
>  - unlock private lock if claim_direct_mode fails (kbuild robot reported)
>  - move unlock to err: out path in trigger handler (kbuild robot inspired)
> 
> Changes in v3:
>  Thanks for the review Jonathan
>  - This patch now depends on 
>    447136effbf4 ("iio: humidity: hdc100x: fix sensor data reads of temp
>    and humidity")
>  - remove i2c functionality check, done in dependent patch
>  - remove unused define HDC100X_ALL_CHANNEL_MASK
>  - define and use available_scan_masks to demux between temp &/or humid
>    data in buffered mode
>  - changed timestamp channel scan_index from 3 to 2.
>  - put back private data lock in read_raw
>    (we'll lock private data lock and claim_direct_mode on raw reads)
>  - remove unneeded NULL parameters in iio_buffer_setup_ops
>  - add private data lock on buffered read
>    We are going to allow configuration changes while the sensor is in
>    buffered mode.  We need to allow the toggling of the Heater Enable bit
>    because the heater only functions during measurements. The lock will
>    ensure that the config change and buffer read transaction do not collide.
>  - blank lines added for readability per reviewer 
> 
> 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 | 130 ++++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 130 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/humidity/Kconfig b/drivers/iio/humidity/Kconfig
> index f155386..5a25569 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 Texas Instruments
>  	  HDC1000 and HDC1008 relative humidity and temperature sensors.
> diff --git a/drivers/iio/humidity/hdc100x.c b/drivers/iio/humidity/hdc100x.c
> index e0c9c70..265c34d 100644
> --- a/drivers/iio/humidity/hdc100x.c
> +++ b/drivers/iio/humidity/hdc100x.c
> @@ -22,11 +22,15 @@
>  
>  #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)
>  
>  struct hdc100x_data {
> @@ -87,22 +91,40 @@ 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(2),
>  };
>  
> +static const unsigned long hdc100x_scan_masks[] = {0x3, 0};
> +
>  static int hdc100x_update_config(struct hdc100x_data *data, int mask, int val)
>  {
>  	int tmp = (~mask & data->config) | val;
> @@ -183,7 +205,14 @@ static int hdc100x_read_raw(struct iio_dev *indio_dev,
>  			*val = hdc100x_get_heater_status(data);
>  			ret = IIO_VAL_INT;
>  		} else {
> +			ret = iio_device_claim_direct_mode(indio_dev);
> +			if (ret) {
> +				mutex_unlock(&data->lock);
> +				return ret;
> +			}
> +
>  			ret = hdc100x_get_measurement(data, chan);
> +			iio_device_release_direct_mode(indio_dev);
>  			if (ret >= 0) {
>  				*val = ret;
>  				ret = IIO_VAL_INT;
> @@ -246,6 +275,78 @@ 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 = {
> +	.postenable  = hdc100x_buffer_postenable,
> +	.predisable  = hdc100x_buffer_predisable,
> +};
> +
> +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 */
> +	mutex_lock(&data->lock);
> +	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;
> +	}
> +
> +	iio_push_to_buffers_with_timestamp(indio_dev, buf,
> +					   iio_get_time_ns(indio_dev));
> +err:
> +	mutex_unlock(&data->lock);
> +	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,
> @@ -258,6 +359,7 @@ 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 | I2C_FUNC_I2C))
> @@ -279,12 +381,35 @@ static int hdc100x_probe(struct i2c_client *client,
>  
>  	indio_dev->channels = hdc100x_channels;
>  	indio_dev->num_channels = ARRAY_SIZE(hdc100x_channels);
> +	indio_dev->available_scan_masks = hdc100x_scan_masks;
>  
>  	/* 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[] = {
> @@ -298,6 +423,7 @@ static struct i2c_driver hdc100x_driver = {
>  		.name	= "hdc100x",
>  	},
>  	.probe = hdc100x_probe,
> +	.remove = hdc100x_remove,
>  	.id_table = hdc100x_id,
>  };
>  module_i2c_driver(hdc100x_driver);
>