Re: [PATCH 5/5] iio: light: us5182d: Add interrupt support and events

[Jonathan Cameron <jic23@kernel.org>]

On 24/11/15 10:59, Adriana Reus wrote:
> Add interrupt support and events for proximity.
> Add two threshold events to signal rising and falling directions.
> 
> Signed-off-by: Adriana Reus <adriana.reus@intel.com>
A few bits and bobs inline...
> ---
>  drivers/iio/light/us5182d.c | 272 +++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 271 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/light/us5182d.c b/drivers/iio/light/us5182d.c
> index 60cab4a..4d1f80d 100644
> --- a/drivers/iio/light/us5182d.c
> +++ b/drivers/iio/light/us5182d.c
> @@ -20,7 +20,10 @@
>  #include <linux/acpi.h>
>  #include <linux/delay.h>
>  #include <linux/i2c.h>
> +#include <linux/iio/events.h>
>  #include <linux/iio/iio.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
>  #include <linux/iio/sysfs.h>
>  #include <linux/mutex.h>
>  #include <linux/pm.h>
> @@ -30,6 +33,8 @@
>  #define US5182D_CFG0_ONESHOT_EN				BIT(6)
>  #define US5182D_CFG0_SHUTDOWN_EN			BIT(7)
>  #define US5182D_CFG0_WORD_ENABLE			BIT(0)
> +#define US5182D_CFG0_PROX				BIT(3)
> +#define US5182D_CFG0_PX_IRQ				BIT(2)
>  
>  #define US5182D_REG_CFG1				0x01
>  #define US5182D_CFG1_ALS_RES16				BIT(4)
> @@ -41,6 +46,7 @@
>  
>  #define US5182D_REG_CFG3				0x03
>  #define US5182D_CFG3_LED_CURRENT100			(BIT(4) | BIT(5))
> +#define US5182D_CFG3_INT_SOURCE_PX			BIT(3)
>  
>  #define US5182D_REG_CFG4				0x10
>  
> @@ -55,6 +61,13 @@
>  #define US5182D_REG_AUTO_LDARK_GAIN		0x29
>  #define US5182D_REG_AUTO_HDARK_GAIN		0x2a
>  
> +/* Thresholds for events: px low (0x08-l, 0x09-h), px high (0x0a-l 0x0b-h) */
> +#define US5182D_REG_PXL_TH			0x08
> +#define US5182D_REG_PXH_TH			0x0a
> +
> +#define US5182D_REG_PXL_TH_DEFAULT		1000
> +#define US5182D_REG_PXH_TH_DEFAULT		30000
> +
>  #define US5182D_OPMODE_ALS			0x01
>  #define US5182D_OPMODE_PX			0x02
>  #define US5182D_OPMODE_SHIFT			4
> @@ -84,6 +97,8 @@
>  #define US5182D_READ_WORD			2
>  #define US5182D_OPSTORE_SLEEP_TIME		20 /* ms */
>  #define US5182D_SLEEP_MS			3000 /* ms */
> +#define US5182D_PXH_TH_DISABLE			0xffff
> +#define US5182D_PXL_TH_DISABLE			0x0000
>  
>  /* Available ranges: [12354, 7065, 3998, 2202, 1285, 498, 256, 138] lux */
>  static const int us5182d_scales[] = {188500, 107800, 61000, 33600, 19600, 7600,
> @@ -119,6 +134,12 @@ struct us5182d_data {
>  	u8 upper_dark_gain;
>  	u16 *us5182d_dark_ths;
>  
> +	u16 px_low_th;
> +	u16 px_high_th;
> +
> +	int rising_en;
> +	int falling_en;
> +
>  	u8 opmode;
>  	u8 power_mode;
>  
> @@ -148,10 +169,26 @@ static const struct {
>  	{US5182D_REG_CFG1, US5182D_CFG1_ALS_RES16},
>  	{US5182D_REG_CFG2, (US5182D_CFG2_PX_RES16 |
>  			    US5182D_CFG2_PXGAIN_DEFAULT)},
> -	{US5182D_REG_CFG3, US5182D_CFG3_LED_CURRENT100},
> +	{US5182D_REG_CFG3, US5182D_CFG3_LED_CURRENT100 |
> +			   US5182D_CFG3_INT_SOURCE_PX},
>  	{US5182D_REG_CFG4, 0x00},
>  };
>  
> +static const struct iio_event_spec us5182d_events[] = {
> +	{
> +		.type = IIO_EV_TYPE_THRESH,
> +		.dir = IIO_EV_DIR_RISING,
> +		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
> +				BIT(IIO_EV_INFO_ENABLE),
> +	},
> +	{
> +		.type = IIO_EV_TYPE_THRESH,
> +		.dir = IIO_EV_DIR_FALLING,
> +		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
> +				BIT(IIO_EV_INFO_ENABLE),
> +	},
> +};
> +
>  static const struct iio_chan_spec us5182d_channels[] = {
>  	{
>  		.type = IIO_LIGHT,
> @@ -161,6 +198,8 @@ static const struct iio_chan_spec us5182d_channels[] = {
>  	{
>  		.type = IIO_PROXIMITY,
>  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> +		.event_spec = us5182d_events,
> +		.num_event_specs = ARRAY_SIZE(us5182d_events),
>  	}
>  };
>  
> @@ -477,11 +516,199 @@ static int us5182d_write_raw(struct iio_dev *indio_dev,
>  	return -EINVAL;
>  }
>  
> +static int us5182d_setup_prox(struct iio_dev *indio_dev,
> +			      enum iio_event_direction dir, u16 val)
> +{
> +	struct us5182d_data *data = iio_priv(indio_dev);
> +	int ret = 0;
> +
> +	if (dir == IIO_EV_DIR_FALLING)
> +		ret = i2c_smbus_write_word_data(data->client,
> +						US5182D_REG_PXL_TH, val);
> +
> +	if (dir == IIO_EV_DIR_RISING)
> +		ret = i2c_smbus_write_word_data(data->client,
> +						US5182D_REG_PXH_TH, val);
> +
> +	return ret;
return directly above, no need for the local ret variable and return
0 here.
> +}
> +
> +static int us5182d_read_thresh(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 us5182d_data *data = iio_priv(indio_dev);
> +
> +	switch (dir) {
> +	case IIO_EV_DIR_RISING:
> +		mutex_lock(&data->lock);
> +		*val = data->px_high_th;
> +		mutex_unlock(&data->lock);
> +		break;
> +	case IIO_EV_DIR_FALLING:
> +		mutex_lock(&data->lock);
> +		*val = data->px_low_th;
> +		mutex_unlock(&data->lock);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return IIO_VAL_INT;
> +}
> +
> +static int us5182d_write_thresh(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 us5182d_data *data = iio_priv(indio_dev);
> +	int ret = 0;
There is no path in which ret is used and not overriden that I can see
so drop the initialize.

> +
> +	if (val < 0 || val > USHRT_MAX || val2 != 0)
> +		return -EINVAL;
> +
> +	switch (dir) {
> +	case IIO_EV_DIR_RISING:
> +		mutex_lock(&data->lock);
> +		if (data->rising_en) {
> +			ret = us5182d_setup_prox(indio_dev, dir, val);
> +			if (ret < 0)
> +				goto err;
> +		}
> +		data->px_high_th = val;
> +		mutex_unlock(&data->lock);
> +		break;
> +	case IIO_EV_DIR_FALLING:
> +		mutex_lock(&data->lock);
> +		if (data->falling_en) {
> +			ret = us5182d_setup_prox(indio_dev, dir, val);
> +			if (ret < 0)
> +				goto err;
> +		}
> +		data->px_low_th = val;
> +		mutex_unlock(&data->lock);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +err:
> +	mutex_unlock(&data->lock);
> +	return ret;
> +}
> +
> +static int us5182d_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 us5182d_data *data = iio_priv(indio_dev);
> +	int ret;
> +
> +	switch (dir) {
> +	case IIO_EV_DIR_RISING:
> +		mutex_lock(&data->lock);
> +		ret = data->rising_en;
> +		mutex_unlock(&data->lock);

> +		break;
> +	case IIO_EV_DIR_FALLING:
> +		mutex_lock(&data->lock);
> +		ret = data->falling_en;
> +		mutex_unlock(&data->lock);
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	return ret;
> +}
> +
> +static int us5182d_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 us5182d_data *data = iio_priv(indio_dev);
> +	int ret;
> +	u16 new_th;
> +
> +	mutex_lock(&data->lock);
> +
> +	switch (dir) {
> +	case IIO_EV_DIR_RISING:
> +		if (data->rising_en == state)
> +			goto out;
> +		new_th = US5182D_PXH_TH_DISABLE;
> +		if (state) {
> +			data->power_mode = US5182D_CONTINUOUS;
> +			ret = us5182d_set_power_state(data, true);
> +			if (ret < 0)
> +				goto err;
> +			ret = us5182d_px_enable(data);
> +			if (ret < 0)
> +				goto err_poweroff;
> +			new_th = data->px_high_th;
> +		}
> +		ret = us5182d_setup_prox(indio_dev, dir, new_th);
> +		if (ret < 0)
> +			goto err_poweroff;
> +		data->rising_en = state;
> +		break;
> +	case IIO_EV_DIR_FALLING:
> +		if (data->falling_en == state)
> +			goto out;
> +		new_th =  US5182D_PXL_TH_DISABLE;
> +		if (state) {
> +			data->power_mode = US5182D_CONTINUOUS;
> +			ret = us5182d_set_power_state(data, true);
> +			if (ret < 0)
> +				goto err;
> +			ret = us5182d_px_enable(data);
> +			if (ret < 0)
> +				goto err_poweroff;
> +			new_th = data->px_low_th;
> +		}
> +		ret = us5182d_setup_prox(indio_dev, dir, new_th);
> +		if (ret < 0)
> +			goto err_poweroff;
> +		data->falling_en = state;
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		goto err;
> +	}
> +
> +	if (!state) {
> +		ret = us5182d_set_power_state(data, false);
> +		if (ret < 0)
> +			goto err;
> +	}
> +
> +	if (!data->falling_en && !data->rising_en && !data->default_continuous)
> +		data->power_mode = US5182D_ONESHOT;
> +
> +out:
> +	mutex_unlock(&data->lock);
> +	return 0;
I'm not terribly keen on these multiple exit routes reached by gotos but
can't see a trivial way to clean this up other than simply having
mutex unlock and return inline where you use the above goto.  Might
be easier to follow.

> +err_poweroff:
> +	if (state)
> +		us5182d_set_power_state(data, false);
> +err:
> +	mutex_unlock(&data->lock);
> +	return ret;
> +}
> +
>  static const struct iio_info us5182d_info = {
>  	.driver_module	= THIS_MODULE,
>  	.read_raw = us5182d_read_raw,
>  	.write_raw = us5182d_write_raw,
>  	.attrs = &us5182d_attr_group,
> +	.read_event_value = &us5182d_read_thresh,
> +	.write_event_value = &us5182d_write_thresh,
> +	.read_event_config = &us5182d_read_event_config,
> +	.write_event_config = &us5182d_write_event_config,
>  };
>  
>  static int us5182d_reset(struct iio_dev *indio_dev)
> @@ -503,6 +730,9 @@ static int us5182d_init(struct iio_dev *indio_dev)
>  
>  	data->opmode = 0;
>  	data->power_mode = US5182D_CONTINUOUS;
> +	data->px_low_th = US5182D_REG_PXL_TH_DEFAULT;
> +	data->px_high_th = US5182D_REG_PXH_TH_DEFAULT;
> +
>  	for (i = 0; i < ARRAY_SIZE(us5182d_regvals); i++) {
>  		ret = i2c_smbus_write_byte_data(data->client,
>  						us5182d_regvals[i].reg,
> @@ -573,6 +803,36 @@ static int  us5182d_dark_gain_config(struct iio_dev *indio_dev)
>  					 US5182D_REG_DARK_AUTO_EN_DEFAULT);
>  }
>  
> +static irqreturn_t us5182d_irq_thread_handler(int irq, void *private)
> +{
> +	struct iio_dev *indio_dev = private;
> +	struct us5182d_data *data = iio_priv(indio_dev);
> +	enum iio_event_direction dir;
> +	int ret;
> +	int approach;
> +	u64 ev;
> +
> +	ret = i2c_smbus_read_byte_data(data->client, US5182D_REG_CFG0);
> +	if (ret < 0) {
> +		dev_err(&data->client->dev, "i2c transfer error in irq\n");
> +		return IRQ_HANDLED;
> +	}
> +
> +	approach = ret & US5182D_CFG0_PROX;
> +	dir = approach ? IIO_EV_DIR_RISING : IIO_EV_DIR_FALLING;
> +	ev = IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, 1, IIO_EV_TYPE_THRESH, dir);
> +
> +	iio_push_event(indio_dev, ev, iio_get_time_ns());
I might argue slightly in favour of doing the timestamp acquire in the
top half, but I doubt anyone is ever that bothered by precise timing
of such an event so lets leave it as is for now.

> +
> +	ret = ret & ~US5182D_CFG0_PX_IRQ;
> +
>From a reability point of view, I'd have been tempted to do this manipulation
directly in the next call - out here you almost look ato be manipulating
return values rather than working out the value to write.

> +	ret = i2c_smbus_write_byte_data(data->client, US5182D_REG_CFG0, ret);

> +	if (ret < 0)
> +		dev_err(&data->client->dev, "i2c transfer error in irq\n");
> +
> +	return IRQ_HANDLED;
> +}
> +
>  static int us5182d_probe(struct i2c_client *client,
>  			 const struct i2c_device_id *id)
>  {
> @@ -604,6 +864,16 @@ static int us5182d_probe(struct i2c_client *client,
>  		return (ret < 0) ? ret : -ENODEV;
>  	}
>  
> +	if (client->irq > 0) {
> +		ret = devm_request_threaded_irq(&client->dev, client->irq, NULL,
> +						us5182d_irq_thread_handler,
> +						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
> +						"us5182d-irq", indio_dev);
> +		if (ret < 0)
> +			return ret;
> +	} else
> +		dev_warn(&client->dev, "no valid irq found\n");
> +
>  	us5182d_get_platform_data(indio_dev);
>  	ret = us5182d_init(indio_dev);
>  	if (ret < 0)
>