Re: [PATCH 1/4] iio: proximity: vcnl3020: add periodic mode

Jonathan Cameron
2021-05-02T18:00:08Z

On Fri, 30 Apr 2021 18:24:16 +0300
Ivan Mikhaylov <i.mikhaylov@yadro.com> wrote:

> Add the possibility to run proximity sensor in periodic measurement
> mode.

Without an interrupt? Unusual and perhaps best left to userspace.

>
> Signed-off-by: Ivan Mikhaylov <i.mikhaylov@yadro.com>
> ---
> drivers/iio/proximity/vcnl3020.c | 138 +++++++++++++++++++++++++++++++
> 1 file changed, 138 insertions(+)
>
> diff --git a/drivers/iio/proximity/vcnl3020.c b/drivers/iio/proximity/vcnl3020.c
> index 43817f6b3086..25c6bdba3ede 100644
> --- a/drivers/iio/proximity/vcnl3020.c
> +++ b/drivers/iio/proximity/vcnl3020.c
> @@ -36,6 +36,21 @@
> #define VCNL_PS_OD BIT(3) /* start on-demand proximity
> * measurement
> */
> +#define VCNL_PS_EN BIT(1) /* Enables periodic proximity
> + * measurement
> + */
> +#define VCNL_PS_SELFTIMED_EN BIT(0) /* Enables state machine and LP
> + * oscillator for self timed
> + * measurements

This rather suggests that you should just put comments on their own lines
as it will involve less wrapping and ultimately be more compact and readable!

> + */
> +
> +/* Bit masks for ICR */
> +#define VCNL_ICR_THRES_EN BIT(1) /* Enable interrupts on low or high
> + * thresholds */
> +
> +/* Bit masks for ISR */
> +#define VCNL_INT_TH_HI BIT(0) /* High threshold hit */
> +#define VCNL_INT_TH_LOW BIT(1) /* Low threshold hit */
>
> #define VCNL_ON_DEMAND_TIMEOUT_US 100000
> #define VCNL_POLL_US 20000
> @@ -215,12 +230,124 @@ static int vcnl3020_write_proxy_samp_freq(struct vcnl3020_data *data, int val,
> return regmap_write(data->regmap, VCNL_PROXIMITY_RATE, index);
> }
>
> +static bool vcnl3020_is_in_periodic_mode(struct vcnl3020_data *data)
> +{
> + int rc;
> + unsigned int cmd;
> +
> + rc = regmap_read(data->regmap, VCNL_COMMAND, &cmd);
> + if (rc)
> + return false;
> +
> + return !!(cmd & VCNL_PS_SELFTIMED_EN);
> +}
> +
> +static bool vcnl3020_is_thr_enabled(struct vcnl3020_data *data)
> +{
> + int rc;
> + unsigned int icr;
> +
> + rc = regmap_read(data->regmap, VCNL_PS_ICR, &icr);
> + if (rc)
> + return false;
> +
> + return !!(icr & VCNL_ICR_THRES_EN);
> +}
> +
> +static int vcnl3020_config_threshold(struct iio_dev *indio_dev, bool state)
> +{
> + struct vcnl3020_data *data = iio_priv(indio_dev);
> + int rc;
> + int icr;
> + int cmd;
> + int isr;
> +
> + if (state) {
> + rc = iio_device_claim_direct_mode(indio_dev);

Device doesn't support buffered mode, so this is a lock as in patch 3.
Don't do that as that isn't the intended use

> + if (rc)
> + return rc;
> +
> + /* Enable periodic measurement of proximity data. */
> + cmd = VCNL_PS_EN | VCNL_PS_SELFTIMED_EN;
> +
> + /*
> + * Enable interrupts on threshold, for proximity data by
> + * default.
> + */
> + icr = VCNL_ICR_THRES_EN;
> + } else {
> + if (!vcnl3020_is_thr_enabled(data))
> + return 0;
> +
> + cmd = 0;
> + icr = 0;
> + isr = 0;
> + }
> +
> + rc = regmap_write(data->regmap, VCNL_COMMAND, cmd);
> + if (rc)
> + goto end;
> +
> + rc = regmap_write(data->regmap, VCNL_PS_ICR, icr);
> + if (rc)
> + goto end;
> +
> + if (!state)
> + /* Clear interrupts */

Given you don't seem to have an interrupt. I guess this is clearing
a status flag?

> + rc = regmap_write(data->regmap, VCNL_ISR, isr);
> +
> +end:
> + if (state)
> + iio_device_release_direct_mode(indio_dev);

I would just allow for the small amount of repeated code and do only
one condition on if (state) in this function.

> +
> + return rc;
> +}
> +
> +static int vcnl3020_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)
> +{
> + switch (chan->type) {
> + case IIO_PROXIMITY:
> + return vcnl3020_config_threshold(indio_dev, state);
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static int vcnl3020_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 vcnl3020_data *data = iio_priv(indio_dev);
> +
> + switch (chan->type) {
> + case IIO_PROXIMITY:
> + return vcnl3020_is_thr_enabled(data);
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static const struct iio_event_spec vcnl3020_event_spec[] = {
> + {
> + .type = IIO_EV_TYPE_THRESH,
> + .dir = IIO_EV_DIR_EITHER,
> + .mask_separate = BIT(IIO_EV_INFO_ENABLE),
> + },
> +};
> +
> static const struct iio_chan_spec vcnl3020_channels[] = {
> {
> .type = IIO_PROXIMITY,
> .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> BIT(IIO_CHAN_INFO_SAMP_FREQ),
> .info_mask_separate_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
> + .event_spec = vcnl3020_event_spec,
> + .num_event_specs = ARRAY_SIZE(vcnl3020_event_spec),
> },
> };
>
> @@ -233,6 +360,11 @@ static int vcnl3020_read_raw(struct iio_dev *indio_dev,
>
> switch (mask) {
> case IIO_CHAN_INFO_RAW:
> +
> + /* Protect against event capture. */
> + if (vcnl3020_is_in_periodic_mode(data))
> + return -EBUSY;
> +
> rc = vcnl3020_measure_proximity(data, val);
> if (rc)
> return rc;
> @@ -254,6 +386,10 @@ static int vcnl3020_write_raw(struct iio_dev *indio_dev,
> int rc;
> struct vcnl3020_data *data = iio_priv(indio_dev);
>
> + /* Protect against event capture. */
> + if (vcnl3020_is_in_periodic_mode(data))
> + return -EBUSY;
> +
> switch (mask) {
> case IIO_CHAN_INFO_SAMP_FREQ:
> rc = iio_device_claim_direct_mode(indio_dev);
> @@ -287,6 +423,8 @@ static const struct iio_info vcnl3020_info = {
> .read_raw = vcnl3020_read_raw,
> .write_raw = vcnl3020_write_raw,
> .read_avail = vcnl3020_read_avail,
> + .read_event_config = vcnl3020_read_event_config,
> + .write_event_config = vcnl3020_write_event_config,
> };
>
> static const struct regmap_config vcnl3020_regmap_config = {