linux-kernel - Re: [PATCH 2/5] max44000: Initial support for proximity reading

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Date:	Sun, 10 Apr 2016 14:14:20 +0100
From:	Jonathan Cameron <jic23@...nel.org>
To:	Crestez Dan Leonard <leonard.crestez@...el.com>,
	linux-iio@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, Hartmut Knaack <knaack.h@....de>,
	Lars-Peter Clausen <lars@...afoo.de>,
	Peter Meerwald-Stadler <pmeerw@...erw.net>,
	Daniel Baluta <daniel.baluta@...el.com>
Subject: Re: [PATCH 2/5] max44000: Initial support for proximity reading

On 07/04/16 17:21, Crestez Dan Leonard wrote:
> The proximity sensor relies on sending pulses to an external IR led and
> it is disabled by default on powerup. The driver will enable it with a
> default power setting.
> 
> Signed-off-by: Crestez Dan Leonard <leonard.crestez@...el.com>
One trivial point inline...
> ---
>  drivers/iio/light/max44000.c | 61 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 61 insertions(+)
> 
> diff --git a/drivers/iio/light/max44000.c b/drivers/iio/light/max44000.c
> index 7c12153..10a0fe8 100644
> --- a/drivers/iio/light/max44000.c
> +++ b/drivers/iio/light/max44000.c
> @@ -41,6 +41,23 @@
>  #define MAX44000_REG_TRIM_GAIN_GREEN	0x0f
>  #define MAX44000_REG_TRIM_GAIN_IR	0x10
>  
> +/* REG_CFG bits */
> +#define MAX44000_CFG_ALSINTE		0x01
> +#define MAX44000_CFG_PRXINTE		0x02
> +#define MAX44000_CFG_MASK		0x1c
> +#define MAX44000_CFG_MODE_SHUTDOWN	0x00
> +#define MAX44000_CFG_MODE_ALS_GIR	0x04
> +#define MAX44000_CFG_MODE_ALS_G		0x08
> +#define MAX44000_CFG_MODE_ALS_IR	0x0c
> +#define MAX44000_CFG_MODE_ALS_PRX	0x10
> +#define MAX44000_CFG_MODE_PRX		0x14
> +#define MAX44000_CFG_TRIM		0x20
> +
> +/* REG_TX bits */
> +#define MAX44000_LED_CURRENT_MASK	0xf
> +#define MAX44000_LED_CURRENT_MAX	11
> +#define MAX44000_LED_CURRENT_DEFAULT	6
> +
>  #define MAX44000_ALSDATA_OVERFLOW	0x4000
>  
>  #define MAX44000_REGMASK_READABLE	0x419fff
> @@ -60,6 +77,12 @@ static const struct iio_chan_spec max44000_channels[] = {
>  	{
>  		.type = IIO_LIGHT,
>  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> +		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |
> +					    BIT(IIO_CHAN_INFO_INT_TIME),
> +	},
> +	{
> +		.type = IIO_PROXIMITY,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
>  		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
>  	},
>  };
> @@ -90,11 +113,23 @@ static inline int max44000_read_alsval(struct max44000_data *data)
>  	return regval;
>  }
>  
> +static inline int max44000_write_led_current_raw(struct max44000_data *data, int val)
> +{
> +	/* Maybe we should clamp the value instead? */
> +	if (val < 0 || val > MAX44000_LED_CURRENT_MAX)
> +		return -ERANGE;
> +	if (val >= 8)
> +		val += 4;
> +	return regmap_write_bits(data->regmap, MAX44000_REG_CFG_TX,
> +				 MAX44000_LED_CURRENT_MASK, val);
> +}
> +
>  static int max44000_read_raw(struct iio_dev *indio_dev,
>  			     struct iio_chan_spec const *chan,
>  			     int *val, int *val2, long mask)
>  {
>  	struct max44000_data *data = iio_priv(indio_dev);
> +	unsigned int regval;
>  	int ret;
>  
>  	switch (mask) {
> @@ -109,6 +144,15 @@ static int max44000_read_raw(struct iio_dev *indio_dev,
>  			*val = ret;
>  			return IIO_VAL_INT;
>  
> +		case IIO_PROXIMITY:
> +			mutex_lock(&data->lock);
> +			ret = regmap_read(data->regmap, MAX44000_REG_PRX_DATA, &regval);
> +			mutex_unlock(&data->lock);
> +			if (ret < 0)
> +				return ret;
> +			*val = regval;
> +			return IIO_VAL_INT;
> +
>  		default:
>  			return -EINVAL;
>  		}
> @@ -244,6 +288,23 @@ static int max44000_probe(struct i2c_client *client,
>  		return ret;
>  	}
>  
> +	/* By default the LED pulse used for the proximity sensor is disabled.
Please run checkpatch.pl on these.  It would probably have complained about
the multiline comment syntax here.
> +	 * Set a middle value so that we get some sort of valid data by default.
> +	 */
> +	ret = max44000_write_led_current_raw(data, MAX44000_LED_CURRENT_DEFAULT);
> +	if (ret < 0) {
> +		dev_err(&data->client->dev, "failed to write init config: %d\n", ret);
> +		return ret;
> +	}
> +
> +	/* By default set in ALS_PRX mode which allows easy reading of both values. */
> +	reg = MAX44000_CFG_TRIM | MAX44000_CFG_MODE_ALS_PRX;
> +	ret = regmap_write(data->regmap, MAX44000_REG_CFG_MAIN, reg);
> +	if (ret < 0) {
> +		dev_err(&data->client->dev, "failed to write init config: %d\n", ret);
> +		return ret;
> +	}
> +
>  	return iio_device_register(indio_dev);
>  }
>  
>