Re: [PATCH v2 2/2] iio: light: tcs3472: support out-of-threshold events

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On Tue, 27 Jun 2017 00:44:55 +0900
Akinobu Mita <akinobu.mita@xxxxxxxxx> wrote:

> The TCS3472 device provides interrupt signal for out-of-threshold events
> with persistence filter.
> 
> This change adds interrupt support for the threshold events and enables
> to configure the period of time by persistence filter.
> 
> Cc: Peter Meerwald <pmeerw@xxxxxxxxxx>
> Cc: Jonathan Cameron <jic23@xxxxxxxxxx>
> Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
Looks fine to me, but I'd like to leave a little longer for Peter to
comment if he wishes to.  Also Jon might have some input.

Jonathan
> ---
> * Changes from v1 (addressed comment from Peter Meerwald)
> - Neaten the special function code notation
> - Improve the code comment for tcs3472_intr_pers[]
> - Fix error path with invalid event info in write_event_value()
> - Handle correctly if the negative period time is specified (round to the
>   minimum available period time)
> - Remove redundant the PERS register write
> - Call free_irq() in reverse order of the initialization.
> 
>  drivers/iio/light/tcs3472.c | 262 ++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 254 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/iio/light/tcs3472.c b/drivers/iio/light/tcs3472.c
> index 09e6ca5..e1c8a07 100644
> --- a/drivers/iio/light/tcs3472.c
> +++ b/drivers/iio/light/tcs3472.c
> @@ -13,7 +13,7 @@
>   *
>   * Datasheet: http://ams.com/eng/content/download/319364/1117183/file/TCS3472_Datasheet_EN_v2.pdf
>   *
> - * TODO: interrupt support, thresholds, wait time
> + * TODO: wait time
>   */
>  
>  #include <linux/module.h>
> @@ -23,6 +23,7 @@
>  
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
> +#include <linux/iio/events.h>
>  #include <linux/iio/trigger_consumer.h>
>  #include <linux/iio/buffer.h>
>  #include <linux/iio/triggered_buffer.h>
> @@ -31,12 +32,15 @@
>  
>  #define TCS3472_COMMAND BIT(7)
>  #define TCS3472_AUTO_INCR BIT(5)
> +#define TCS3472_SPECIAL_FUNC (BIT(5) | BIT(6))
> +
> +#define TCS3472_INTR_CLEAR (TCS3472_COMMAND | TCS3472_SPECIAL_FUNC | 0x06)
>  
>  #define TCS3472_ENABLE (TCS3472_COMMAND | 0x00)
>  #define TCS3472_ATIME (TCS3472_COMMAND | 0x01)
>  #define TCS3472_WTIME (TCS3472_COMMAND | 0x03)
> -#define TCS3472_AILT (TCS3472_COMMAND | 0x04)
> -#define TCS3472_AIHT (TCS3472_COMMAND | 0x06)
> +#define TCS3472_AILT (TCS3472_COMMAND | TCS3472_AUTO_INCR | 0x04)
> +#define TCS3472_AIHT (TCS3472_COMMAND | TCS3472_AUTO_INCR | 0x06)
>  #define TCS3472_PERS (TCS3472_COMMAND | 0x0c)
>  #define TCS3472_CONFIG (TCS3472_COMMAND | 0x0d)
>  #define TCS3472_CONTROL (TCS3472_COMMAND | 0x0f)
> @@ -47,19 +51,42 @@
>  #define TCS3472_GDATA (TCS3472_COMMAND | TCS3472_AUTO_INCR | 0x18)
>  #define TCS3472_BDATA (TCS3472_COMMAND | TCS3472_AUTO_INCR | 0x1a)
>  
> +#define TCS3472_STATUS_AINT BIT(4)
>  #define TCS3472_STATUS_AVALID BIT(0)
> +#define TCS3472_ENABLE_AIEN BIT(4)
>  #define TCS3472_ENABLE_AEN BIT(1)
>  #define TCS3472_ENABLE_PON BIT(0)
>  #define TCS3472_CONTROL_AGAIN_MASK (BIT(0) | BIT(1))
>  
>  struct tcs3472_data {
>  	struct i2c_client *client;
> +	struct mutex lock;
> +	u16 low_thresh;
> +	u16 high_thresh;
>  	u8 enable;
>  	u8 control;
>  	u8 atime;
> +	u8 apers;
>  	u16 buffer[8]; /* 4 16-bit channels + 64-bit timestamp */
>  };
>  
> +static const struct iio_event_spec tcs3472_events[] = {
> +	{
> +		.type = IIO_EV_TYPE_THRESH,
> +		.dir = IIO_EV_DIR_RISING,
> +		.mask_separate = BIT(IIO_EV_INFO_VALUE),
> +	}, {
> +		.type = IIO_EV_TYPE_THRESH,
> +		.dir = IIO_EV_DIR_FALLING,
> +		.mask_separate = BIT(IIO_EV_INFO_VALUE),
> +	}, {
> +		.type = IIO_EV_TYPE_THRESH,
> +		.dir = IIO_EV_DIR_EITHER,
> +		.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
> +				 BIT(IIO_EV_INFO_PERIOD),
> +	},
> +};
> +
>  #define TCS3472_CHANNEL(_color, _si, _addr) { \
>  	.type = IIO_INTENSITY, \
>  	.modified = 1, \
> @@ -75,6 +102,8 @@ struct tcs3472_data {
>  		.storagebits = 16, \
>  		.endianness = IIO_CPU, \
>  	}, \
> +	.event_spec = _si ? NULL : tcs3472_events, \
> +	.num_event_specs = _si ? 0 : ARRAY_SIZE(tcs3472_events), \
>  }
>  
>  static const int tcs3472_agains[] = { 1, 4, 16, 60 };
> @@ -182,6 +211,166 @@ static int tcs3472_write_raw(struct iio_dev *indio_dev,
>  	return -EINVAL;
>  }
>  
> +/*
> + * Translation from APERS field value to the number of consecutive out-of-range
> + * clear channel values before an interrupt is generated
> + */
> +static const int tcs3472_intr_pers[] = {
> +	0, 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60
> +};
> +
> +static int tcs3472_read_event(struct iio_dev *indio_dev,
> +	const struct iio_chan_spec *chan, enum iio_event_type type,
> +	enum iio_event_direction dir, enum iio_event_info info, int *val,
> +	int *val2)
> +{
> +	struct tcs3472_data *data = iio_priv(indio_dev);
> +	int ret;
> +	unsigned int period;
> +
> +	mutex_lock(&data->lock);
> +
> +	switch (info) {
> +	case IIO_EV_INFO_VALUE:
> +		*val = (dir == IIO_EV_DIR_RISING) ?
> +			data->high_thresh : data->low_thresh;
> +		ret = IIO_VAL_INT;
> +		break;
> +	case IIO_EV_INFO_PERIOD:
> +		period = (256 - data->atime) * 2400 *
> +			tcs3472_intr_pers[data->apers];
> +		*val = period / USEC_PER_SEC;
> +		*val2 = period % USEC_PER_SEC;
> +		ret = IIO_VAL_INT_PLUS_MICRO;
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	mutex_unlock(&data->lock);
> +
> +	return ret;
> +}
> +
> +static int tcs3472_write_event(struct iio_dev *indio_dev,
> +	const struct iio_chan_spec *chan, enum iio_event_type type,
> +	enum iio_event_direction dir, enum iio_event_info info, int val,
> +	int val2)
> +{
> +	struct tcs3472_data *data = iio_priv(indio_dev);
> +	int ret;
> +	u8 command;
> +	int period;
> +	int i;
> +
> +	mutex_lock(&data->lock);
> +	switch (info) {
> +	case IIO_EV_INFO_VALUE:
> +		switch (dir) {
> +		case IIO_EV_DIR_RISING:
> +			command = TCS3472_AIHT;
> +			break;
> +		case IIO_EV_DIR_FALLING:
> +			command = TCS3472_AILT;
> +			break;
> +		default:
> +			ret = -EINVAL;
> +			goto error;
> +		}
> +		ret = i2c_smbus_write_word_data(data->client, command, val);
> +		if (ret)
> +			goto error;
> +
> +		if (dir == IIO_EV_DIR_RISING)
> +			data->high_thresh = val;
> +		else
> +			data->low_thresh = val;
> +		break;
> +	case IIO_EV_INFO_PERIOD:
> +		period = val * USEC_PER_SEC + val2;
> +		for (i = 1; i < ARRAY_SIZE(tcs3472_intr_pers) - 1; i++) {
> +			if (period <= (256 - data->atime) * 2400 *
> +					tcs3472_intr_pers[i])
> +				break;
> +		}
> +		ret = i2c_smbus_write_byte_data(data->client, TCS3472_PERS, i);
> +		if (ret)
> +			goto error;
> +
> +		data->apers = i;
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +error:
> +	mutex_unlock(&data->lock);
> +
> +	return ret;
> +}
> +
> +static int tcs3472_read_event_config(struct iio_dev *indio_dev,
> +	const struct iio_chan_spec *chan, enum iio_event_type type,
> +	enum iio_event_direction dir)
> +{
> +	struct tcs3472_data *data = iio_priv(indio_dev);
> +	int ret;
> +
> +	mutex_lock(&data->lock);
> +	ret = !!(data->enable & TCS3472_ENABLE_AIEN);
> +	mutex_unlock(&data->lock);
> +
> +	return ret;
> +}
> +
> +static int tcs3472_write_event_config(struct iio_dev *indio_dev,
> +	const struct iio_chan_spec *chan, enum iio_event_type type,
> +	enum iio_event_direction dir, int state)
> +{
> +	struct tcs3472_data *data = iio_priv(indio_dev);
> +	int ret = 0;
> +	u8 enable_old;
> +
> +	mutex_lock(&data->lock);
> +
> +	enable_old = data->enable;
> +
> +	if (state)
> +		data->enable |= TCS3472_ENABLE_AIEN;
> +	else
> +		data->enable &= ~TCS3472_ENABLE_AIEN;
> +
> +	if (enable_old != data->enable) {
> +		ret = i2c_smbus_write_byte_data(data->client, TCS3472_ENABLE,
> +						data->enable);
> +		if (ret)
> +			data->enable = enable_old;
> +	}
> +	mutex_unlock(&data->lock);
> +
> +	return ret;
> +}
> +
> +static irqreturn_t tcs3472_event_handler(int irq, void *priv)
> +{
> +	struct iio_dev *indio_dev = priv;
> +	struct tcs3472_data *data = iio_priv(indio_dev);
> +	int ret;
> +
> +	ret = i2c_smbus_read_byte_data(data->client, TCS3472_STATUS);
> +	if (ret >= 0 && (ret & TCS3472_STATUS_AINT)) {
> +		iio_push_event(indio_dev, IIO_UNMOD_EVENT_CODE(IIO_INTENSITY, 0,
> +						IIO_EV_TYPE_THRESH,
> +						IIO_EV_DIR_EITHER),
> +				iio_get_time_ns(indio_dev));
> +
> +		i2c_smbus_read_byte_data(data->client, TCS3472_INTR_CLEAR);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
>  static irqreturn_t tcs3472_trigger_handler(int irq, void *p)
>  {
>  	struct iio_poll_func *pf = p;
> @@ -245,6 +434,10 @@ static const struct attribute_group tcs3472_attribute_group = {
>  static const struct iio_info tcs3472_info = {
>  	.read_raw = tcs3472_read_raw,
>  	.write_raw = tcs3472_write_raw,
> +	.read_event_value = tcs3472_read_event,
> +	.write_event_value = tcs3472_write_event,
> +	.read_event_config = tcs3472_read_event_config,
> +	.write_event_config = tcs3472_write_event_config,
>  	.attrs = &tcs3472_attribute_group,
>  	.driver_module = THIS_MODULE,
>  };
> @@ -263,6 +456,7 @@ static int tcs3472_probe(struct i2c_client *client,
>  	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->info = &tcs3472_info;
> @@ -292,12 +486,29 @@ static int tcs3472_probe(struct i2c_client *client,
>  		return ret;
>  	data->atime = ret;
>  
> +	ret = i2c_smbus_read_word_data(data->client, TCS3472_AILT);
> +	if (ret < 0)
> +		return ret;
> +	data->low_thresh = ret;
> +
> +	ret = i2c_smbus_read_word_data(data->client, TCS3472_AIHT);
> +	if (ret < 0)
> +		return ret;
> +	data->high_thresh = ret;
> +
> +	data->apers = 1;
> +	ret = i2c_smbus_write_byte_data(data->client, TCS3472_PERS,
> +					data->apers);
> +	if (ret < 0)
> +		return ret;
> +
>  	ret = i2c_smbus_read_byte_data(data->client, TCS3472_ENABLE);
>  	if (ret < 0)
>  		return ret;
>  
>  	/* enable device */
>  	data->enable = ret | TCS3472_ENABLE_PON | TCS3472_ENABLE_AEN;
> +	data->enable &= ~TCS3472_ENABLE_AIEN;
>  	ret = i2c_smbus_write_byte_data(data->client, TCS3472_ENABLE,
>  		data->enable);
>  	if (ret < 0)
> @@ -308,12 +519,24 @@ static int tcs3472_probe(struct i2c_client *client,
>  	if (ret < 0)
>  		return ret;
>  
> +	if (client->irq) {
> +		ret = request_threaded_irq(client->irq, NULL,
> +					   tcs3472_event_handler,
> +					   IRQF_TRIGGER_FALLING | IRQF_SHARED |
> +					   IRQF_ONESHOT,
> +					   client->name, indio_dev);
> +		if (ret)
> +			goto buffer_cleanup;
> +	}
> +
>  	ret = iio_device_register(indio_dev);
>  	if (ret < 0)
> -		goto buffer_cleanup;
> +		goto free_irq;
>  
>  	return 0;
>  
> +free_irq:
> +	free_irq(client->irq, indio_dev);
>  buffer_cleanup:
>  	iio_triggered_buffer_cleanup(indio_dev);
>  	return ret;
> @@ -321,8 +544,19 @@ static int tcs3472_probe(struct i2c_client *client,
>  
>  static int tcs3472_powerdown(struct tcs3472_data *data)
>  {
> -	return i2c_smbus_write_byte_data(data->client, TCS3472_ENABLE,
> -		data->enable & ~(TCS3472_ENABLE_AEN | TCS3472_ENABLE_PON));
> +	int ret;
> +	u8 enable_mask = TCS3472_ENABLE_AEN | TCS3472_ENABLE_PON;
> +
> +	mutex_lock(&data->lock);
> +
> +	ret = i2c_smbus_write_byte_data(data->client, TCS3472_ENABLE,
> +		data->enable & ~enable_mask);
> +	if (!ret)
> +		data->enable &= ~enable_mask;
> +
> +	mutex_unlock(&data->lock);
> +
> +	return ret;
>  }
>  
>  static int tcs3472_remove(struct i2c_client *client)
> @@ -330,6 +564,7 @@ static int tcs3472_remove(struct i2c_client *client)
>  	struct iio_dev *indio_dev = i2c_get_clientdata(client);
>  
>  	iio_device_unregister(indio_dev);
> +	free_irq(client->irq, indio_dev);
>  	iio_triggered_buffer_cleanup(indio_dev);
>  	tcs3472_powerdown(iio_priv(indio_dev));
>  
> @@ -348,8 +583,19 @@ static int tcs3472_resume(struct device *dev)
>  {
>  	struct tcs3472_data *data = iio_priv(i2c_get_clientdata(
>  		to_i2c_client(dev)));
> -	return i2c_smbus_write_byte_data(data->client, TCS3472_ENABLE,
> -		data->enable | (TCS3472_ENABLE_AEN | TCS3472_ENABLE_PON));
> +	int ret;
> +	u8 enable_mask = TCS3472_ENABLE_AEN | TCS3472_ENABLE_PON;
> +
> +	mutex_lock(&data->lock);
> +
> +	ret = i2c_smbus_write_byte_data(data->client, TCS3472_ENABLE,
> +		data->enable | enable_mask);
> +	if (!ret)
> +		data->enable |= enable_mask;
> +
> +	mutex_unlock(&data->lock);
> +
> +	return ret;
>  }
>  #endif
>  

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