Re: [PATCH v2 2/2] iio: light: vcnl4000: Add ps_it attributes for vcnl4040

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 23 Sep 2022 13:40:31 +0200
Mårten Lindahl <marten.lindahl@axis.com> wrote:

> Add read/write attribute for proximity integration time, and read
> attribute for available proximity integration times for the vcnl4040
> chip.
> 
> Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com>
Hi Mårten,

One minor comment inline given I've asked for changes that mean you'll
probably be doing a v3 anyway.

Thanks,

Jonathan

> ---
>  drivers/iio/light/vcnl4000.c | 129 ++++++++++++++++++++++++++++++++++-
>  1 file changed, 126 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/light/vcnl4000.c b/drivers/iio/light/vcnl4000.c
> index b2ecf8af1aa5..056079b592c6 100644
> --- a/drivers/iio/light/vcnl4000.c
> +++ b/drivers/iio/light/vcnl4000.c
> @@ -17,6 +17,7 @@
>   *   interrupts (VCNL4040, VCNL4200)
>   */
>  
> +#include <linux/bitfield.h>
>  #include <linux/module.h>
>  #include <linux/i2c.h>
>  #include <linux/err.h>
> @@ -76,6 +77,7 @@
>  
>  #define VCNL4040_ALS_CONF_ALS_SD	BIT(0) /* Enable ambient light sensor */
>  #define VCNL4040_PS_CONF1_PS_SD	BIT(0) /* Enable proximity sensor */
> +#define VCNL4040_PS_CONF2_PS_IT	GENMASK(3, 1) /* Proximity integration time */
>  
>  /* Bit masks for interrupt registers. */
>  #define VCNL4010_INT_THR_SEL	BIT(0) /* Select threshold interrupt source */
> @@ -104,6 +106,17 @@ static const int vcnl4010_prox_sampling_frequency[][2] = {
>  	{250, 0},
>  };
>  
> +static const int vcnl4040_ps_it_times[][2] = {
> +	{0, 100},
> +	{0, 150},
> +	{0, 200},
> +	{0, 250},
> +	{0, 300},
> +	{0, 350},
> +	{0, 400},
> +	{0, 800},
> +};
> +
>  #define VCNL4000_SLEEP_DELAY_MS	2000 /* before we enter pm_runtime_suspend */
>  
>  enum vcnl4000_device_ids {
> @@ -470,6 +483,55 @@ static int vcnl4000_set_pm_runtime_state(struct vcnl4000_data *data, bool on)
>  	return ret;
>  }
>  
> +static int vcnl4040_read_ps_it(struct vcnl4000_data *data, int *val, int *val2)
> +{
> +	int ret;
> +
> +	ret = i2c_smbus_read_word_data(data->client, VCNL4200_PS_CONF1);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = FIELD_GET(VCNL4040_PS_CONF2_PS_IT, ret);
> +
> +	if (ret >= ARRAY_SIZE(vcnl4040_ps_it_times))
> +		return -EINVAL;
> +
> +	*val = vcnl4040_ps_it_times[ret][0];
> +	*val2 = vcnl4040_ps_it_times[ret][1];
> +
> +	return 0;
> +}
> +
> +static ssize_t vcnl4040_write_ps_it(struct vcnl4000_data *data, int val)
> +{
> +	unsigned int i;
> +	int ret, index = -1;
> +
> +	for (i = 0; i < ARRAY_SIZE(vcnl4040_ps_it_times); i++) {
> +		if (val == vcnl4040_ps_it_times[i][1]) {
> +			index = i;
> +			break;
> +		}
> +	}
> +
> +	if (index < 0)
> +		return -EINVAL;
> +
> +	mutex_lock(&data->vcnl4000_lock);
> +
> +	ret = i2c_smbus_read_word_data(data->client, VCNL4200_PS_CONF1);
> +	if (ret < 0)
> +		goto out;
> +
> +	ret = (ret & ~VCNL4040_PS_CONF2_PS_IT) |
> +	    FIELD_PREP(VCNL4040_PS_CONF2_PS_IT, index);

It can be confusing to read ret both as a temporary to build value ad for the
return code. I would introduce a
u16 val
and build the value in that.

> +	ret = i2c_smbus_write_word_data(data->client, VCNL4200_PS_CONF1, ret);
> +
> +out:
> +	mutex_unlock(&data->vcnl4000_lock);
> +	return ret;
> +}
> +