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

[Alison Schofield <amsfield22@gmail.com>]

On Sat, Sep 03, 2016 at 08:37:27PM +0100, Jonathan Cameron wrote:
> 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@gmail.com>
> > Cc: Daniel Baluta <daniel.baluta@gmail.com>
> 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

It's safe to take this one now.  Thanks!
alisons

> > ---
> > 
> > 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);
> > 
>