Date:   Sun, 26 Apr 2020 10:18:34 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     Mathieu Othacehe <m.othacehe@...il.com>
Cc:     knaack.h@....de, lars@...afoo.de, pmeerw@...erw.net,
        linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 4/4] iio: vcnl4000: Add buffer support for
 VCNL4010/20.

On Wed, 22 Apr 2020 15:08:56 +0200
Mathieu Othacehe <m.othacehe@...il.com> wrote:

> The VCNL4010 and VCNL4020 chips are able to raise interrupts on data ready.
> Use it to provide triggered buffer support for proximity data.
> 
> Those two chips also provide ambient light data. However, they are sampled
> at different rate than proximity data. As this is not handled by the IIO
> framework for now, and the sample frequencies of ambient light data are
> very low, do add buffer support for them.
> 
> Signed-off-by: Mathieu Othacehe <m.othacehe@...il.com>
Looks fine to me.

Jonathan

> ---
>  drivers/iio/light/Kconfig    |   2 +
>  drivers/iio/light/vcnl4000.c | 159 ++++++++++++++++++++++++++++++++++-
>  2 files changed, 159 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> index 74970f18a93b..05f61b1e223a 100644
> --- a/drivers/iio/light/Kconfig
> +++ b/drivers/iio/light/Kconfig
> @@ -506,6 +506,8 @@ config US5182D
>  
>  config VCNL4000
>  	tristate "VCNL4000/4010/4020/4200 combined ALS and proximity sensor"
> +	select IIO_BUFFER
> +	select IIO_TRIGGERED_BUFFER
>  	depends on I2C
>  	help
>  	  Say Y here if you want to build a driver for the Vishay VCNL4000,
> diff --git a/drivers/iio/light/vcnl4000.c b/drivers/iio/light/vcnl4000.c
> index aefb549953ad..edba566ad6f6 100644
> --- a/drivers/iio/light/vcnl4000.c
> +++ b/drivers/iio/light/vcnl4000.c
> @@ -5,6 +5,7 @@
>   *
>   * Copyright 2012 Peter Meerwald <pmeerw@...erw.net>
>   * Copyright 2019 Pursim SPC
> + * Copyright 2020 Mathieu Othacehe <m.othacehe@...il.com>
>   *
>   * IIO driver for:
>   *   VCNL4000/10/20 (7-bit I2C slave address 0x13)
> @@ -13,8 +14,7 @@
>   *
>   * TODO:
>   *   allow to adjust IR current
> - *   periodic ALS/proximity measurement (VCNL4010/20)
> - *   interrupts (VCNL4010/20/40, VCNL4200)
> + *   interrupts (VCNL4040, VCNL4200)
>   */
>  
>  #include <linux/module.h>
> @@ -24,9 +24,13 @@
>  #include <linux/pm_runtime.h>
>  #include <linux/interrupt.h>
>  
> +#include <linux/iio/buffer.h>
>  #include <linux/iio/events.h>
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
> +#include <linux/iio/trigger.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/iio/triggered_buffer.h>
>  
>  #define VCNL4000_DRV_NAME "vcnl4000"
>  #define VCNL4000_PROD_ID	0x01
> @@ -768,7 +772,14 @@ static const struct iio_chan_spec vcnl4010_channels[] = {
>  		.event_spec = vcnl4000_event_spec,
>  		.num_event_specs = ARRAY_SIZE(vcnl4000_event_spec),
>  		.ext_info = vcnl4000_ext_info,
> +		.scan_type = {
> +			.sign = 'u',
> +			.realbits = 16,
> +			.storagebits = 16,
> +			.endianness = IIO_CPU,
> +		},
>  	},
> +	IIO_CHAN_SOFT_TIMESTAMP(1),
>  };
>  
>  static IIO_CONST_ATTR(in_proximity_sampling_frequency_available,
> @@ -882,10 +893,139 @@ static irqreturn_t vcnl4010_irq_thread(int irq, void *p)
>  					  isr & VCNL4010_INT_THR);
>  	}
>  
> +	if (isr & VCNL4010_INT_DRDY && iio_buffer_enabled(indio_dev))
> +		iio_trigger_poll_chained(indio_dev->trig);
> +
>  end:
>  	return IRQ_HANDLED;
>  }
>  
> +static irqreturn_t vcnl4010_trigger_handler(int irq, void *p)
> +{
> +	struct iio_poll_func *pf = p;
> +	struct iio_dev *indio_dev = pf->indio_dev;
> +	struct vcnl4000_data *data = iio_priv(indio_dev);
> +	const unsigned long *active_scan_mask = indio_dev->active_scan_mask;
> +	u16 buffer[8] = {0}; /* 1x16-bit + ts */
> +	bool data_read = false;
> +	unsigned long isr;
> +	int val = 0;
> +	int ret;
> +
> +	ret = i2c_smbus_read_byte_data(data->client, VCNL4010_ISR);
> +	if (ret < 0)
> +		goto end;
> +
> +	isr = ret;
> +
> +	if (test_bit(0, active_scan_mask)) {
> +		if (test_bit(VCNL4010_INT_PROXIMITY, &isr)) {
> +			ret = vcnl4000_read_data(data,
> +						 VCNL4000_PS_RESULT_HI,
> +						 &val);
> +			if (ret < 0)
> +				goto end;
> +
> +			buffer[0] = val;
> +			data_read = true;
> +		}
> +	}
> +
> +	ret = i2c_smbus_write_byte_data(data->client, VCNL4010_ISR,
> +					isr & VCNL4010_INT_DRDY);
> +	if (ret < 0)
> +		goto end;
> +
> +	if (!data_read)
> +		goto end;
> +
> +	iio_push_to_buffers_with_timestamp(indio_dev, buffer,
> +					   iio_get_time_ns(indio_dev));
> +
> +end:
> +	iio_trigger_notify_done(indio_dev->trig);
> +	return IRQ_HANDLED;
> +}
> +
> +static int vcnl4010_buffer_postenable(struct iio_dev *indio_dev)
> +{
> +	struct vcnl4000_data *data = iio_priv(indio_dev);
> +	int ret;
> +	int cmd;
> +
> +	ret = iio_triggered_buffer_postenable(indio_dev);
> +	if (ret)
> +		return ret;
> +
> +	/* Do not enable the buffer if we are already capturing events. */
> +	if (vcnl4010_is_in_periodic_mode(data)) {
> +		ret = -EBUSY;
> +		goto end;
> +	}
> +
> +	ret = i2c_smbus_write_byte_data(data->client, VCNL4010_INT_CTRL,
> +					VCNL4010_INT_PROX_EN);
> +	if (ret < 0)
> +		goto end;
> +
> +	cmd = VCNL4000_SELF_TIMED_EN | VCNL4000_PROX_EN;
> +	ret = i2c_smbus_write_byte_data(data->client, VCNL4000_COMMAND, cmd);
> +	if (ret < 0)
> +		goto end;
> +
> +end:
> +	if (ret < 0)
> +		iio_triggered_buffer_predisable(indio_dev);
> +
> +	return ret;
> +}
> +
> +static int vcnl4010_buffer_predisable(struct iio_dev *indio_dev)
> +{
> +	struct vcnl4000_data *data = iio_priv(indio_dev);
> +	int ret, ret_disable;
> +
> +	ret = i2c_smbus_write_byte_data(data->client, VCNL4010_INT_CTRL, 0);
> +	if (ret < 0)
> +		goto end;
> +
> +	ret = i2c_smbus_write_byte_data(data->client, VCNL4000_COMMAND, 0);
> +
> +end:
> +	ret_disable = iio_triggered_buffer_predisable(indio_dev);
> +	if (ret == 0)
> +		ret = ret_disable;
> +
> +	return ret;
> +}
> +
> +static const struct iio_buffer_setup_ops vcnl4010_buffer_ops = {
> +	.postenable = &vcnl4010_buffer_postenable,
> +	.predisable = &vcnl4010_buffer_predisable,
> +};
> +
> +static const struct iio_trigger_ops vcnl4010_trigger_ops = {
> +	.validate_device = iio_trigger_validate_own_device,
> +};
> +
> +static int vcnl4010_probe_trigger(struct iio_dev *indio_dev)
> +{
> +	struct vcnl4000_data *data = iio_priv(indio_dev);
> +	struct i2c_client *client = data->client;
> +	struct iio_trigger *trigger;
> +
> +	trigger = devm_iio_trigger_alloc(&client->dev, "%s-dev%d",
> +					 indio_dev->name, indio_dev->id);
> +	if (!trigger)
> +		return -ENOMEM;
> +
> +	trigger->dev.parent = &client->dev;
> +	trigger->ops = &vcnl4010_trigger_ops;
> +	iio_trigger_set_drvdata(trigger, indio_dev);
> +
> +	return devm_iio_trigger_register(&client->dev, trigger);
> +}
> +
>  static int vcnl4000_probe(struct i2c_client *client,
>  			  const struct i2c_device_id *id)
>  {
> @@ -922,6 +1062,16 @@ static int vcnl4000_probe(struct i2c_client *client,
>  	indio_dev->modes = INDIO_DIRECT_MODE;
>  
>  	if (client->irq && data->chip_spec->irq_support) {
> +		ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev,
> +						      NULL,
> +						      vcnl4010_trigger_handler,
> +						      &vcnl4010_buffer_ops);
> +		if (ret < 0) {
> +			dev_err(&client->dev,
> +				"unable to setup iio triggered buffer\n");
> +			return ret;
> +		}
> +
>  		ret = devm_request_threaded_irq(&client->dev, client->irq,
>  						NULL, vcnl4010_irq_thread,
>  						IRQF_TRIGGER_FALLING |
> @@ -932,6 +1082,10 @@ static int vcnl4000_probe(struct i2c_client *client,
>  			dev_err(&client->dev, "irq request failed\n");
>  			return ret;
>  		}
> +
> +		ret = vcnl4010_probe_trigger(indio_dev);
> +		if (ret < 0)
> +			return ret;
>  	}
>  
>  	ret = pm_runtime_set_active(&client->dev);
> @@ -1027,5 +1181,6 @@ static struct i2c_driver vcnl4000_driver = {
>  module_i2c_driver(vcnl4000_driver);
>  
>  MODULE_AUTHOR("Peter Meerwald <pmeerw@...erw.net>");
> +MODULE_AUTHOR("Mathieu Othacehe <m.othacehe@...il.com>");
>  MODULE_DESCRIPTION("Vishay VCNL4000 proximity/ambient light sensor driver");
>  MODULE_LICENSE("GPL");

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