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SubjectRE: [PATCH v3 1/1] iio: proximity: vcnl3020: add periodic mode
Date
Hi Ivan,

This looks good. Some comments inline...

> From: Ivan Mikhaylov <i.mikhaylov@yadro.com>
> Sent: Thursday, July 8, 2021 2:41 PM
> To: Jonathan Cameron <jic23@kernel.org>; Lars-Peter Clausen
> <lars@metafoo.de>; Peter Meerwald-Stadler
> <pmeerw@pmeerw.net>
> Cc: Ivan Mikhaylov <i.mikhaylov@yadro.com>; linux-
> kernel@vger.kernel.org; linux-iio@vger.kernel.org; kernel test robot
> <lkp@intel.com>
> Subject: [PATCH v3 1/1] iio: proximity: vcnl3020: add periodic mode
>
> [External]
>
> Add the possibility to run proximity sensor in periodic measurement
> mode with thresholds.
>
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Ivan Mikhaylov <i.mikhaylov@yadro.com>
> ---
> drivers/iio/proximity/vcnl3020.c | 297
> ++++++++++++++++++++++++++++++-
> 1 file changed, 295 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/proximity/vcnl3020.c
> b/drivers/iio/proximity/vcnl3020.c
> index 43817f6b3086..cd5e9a34b93c 100644
> --- a/drivers/iio/proximity/vcnl3020.c
> +++ b/drivers/iio/proximity/vcnl3020.c
> @@ -3,7 +3,6 @@
> * Support for Vishay VCNL3020 proximity sensor on i2c bus.
> * Based on Vishay VCNL4000 driver code.
> *
> - * TODO: interrupts.
> */
>
> #include <linux/module.h>
> @@ -11,9 +10,10 @@
> #include <linux/err.h>
> #include <linux/delay.h>
> #include <linux/regmap.h>
> +#include <linux/interrupt.h>
>
> #include <linux/iio/iio.h>
> -#include <linux/iio/sysfs.h>
> +#include <linux/iio/events.h>
>
> #define VCNL3020_PROD_ID 0x21
>
> @@ -37,6 +37,21 @@
> * measurement
> */
>
> +/* Enables periodic proximity measurement */
> +#define VCNL_PS_EN BIT(1)
> +
> +/* Enables state machine and LP oscillator for self timed
> measurements */
> +#define VCNL_PS_SELFTIMED_EN BIT(0)
> +
> +/* Bit masks for ICR */
> +
> +/* Enable interrupts on low or high thresholds */
> +#define VCNL_ICR_THRES_EN BIT(1)
> +
> +/* 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 +230,230 @@ 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_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)
> +{
> + int rc;
> + struct vcnl3020_data *data = iio_priv(indio_dev);
> + __be16 res;
> +
> + switch (info) {
> + case IIO_EV_INFO_VALUE:
> + switch (dir) {
> + case IIO_EV_DIR_RISING:
> + rc = regmap_bulk_read(data->regmap,
> VCNL_PS_HI_THR_HI,
> + &res, sizeof(res));

Me and Jonathan actually spoke about this in the beginning of
the week [1]. For IIO we enforce that this has to be DMA safe
even though it's a 2 byte transfer... Check on IIO driver's using
' ____cacheline_aligned'. Note, that it actually matters for the
buffer/data to be the last member of the structure...

> + if (rc < 0)
> + return rc;
> + *val = be16_to_cpu(res);
> + return IIO_VAL_INT;
> + case IIO_EV_DIR_FALLING:
> + rc = regmap_bulk_read(data->regmap,
> VCNL_PS_LO_THR_HI,
> + &res, sizeof(res));
> + if (rc < 0)
> + return rc;
> + *val = be16_to_cpu(res);
> + return IIO_VAL_INT;
> + default:
> + return -EINVAL;
> + }
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static int vcnl3020_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)
> +{
> + int rc;
> + __be16 buf;
> + struct vcnl3020_data *data = iio_priv(indio_dev);
> +
> + mutex_lock(&data->lock);
> +
> + switch (info) {
> + case IIO_EV_INFO_VALUE:
> + switch (dir) {
> + case IIO_EV_DIR_RISING:
> + /* 16 bit word/ low * high */
> + buf = cpu_to_be16(val);
> + rc = regmap_bulk_write(data->regmap,
> VCNL_PS_HI_THR_HI,
> + &buf, sizeof(buf));

Typically, AFAIK, ' regmap_bulk_write()' creates a DMA safe bounce
buffer for you. However I don't thinks that's done with that in mind
and I don't see anywhere on docs that this is something we can rely
on. Thus, I would also use the DMA safe buffer here and not rely on
regmap implementation details...

> + if (rc < 0)
> + goto out_mutex;
> + rc = IIO_VAL_INT;
> + goto out_mutex;
> + case IIO_EV_DIR_FALLING:
> + buf = cpu_to_be16(val);
> + rc = regmap_bulk_write(data->regmap,
> VCNL_PS_LO_THR_HI,
> + &buf, sizeof(buf));
> + if (rc < 0)
> + goto out_mutex;
> + rc = IIO_VAL_INT;
> + goto out_mutex;
> + default:
> + rc = -EINVAL;
> + goto out_mutex;
> + }
> + default:
> + rc = -EINVAL;
> + goto out_mutex;
> + }
> +out_mutex:
> + mutex_unlock(&data->lock);
> +
> + return rc;
> +}
> +
> +static int vcnl3020_enable_periodic(struct iio_dev *indio_dev,
> + struct vcnl3020_data *data)
> +{
> + int rc;
> + int cmd;
> +
> + mutex_lock(&data->lock);
> +
> + /* Enable periodic measurement of proximity data. */
> + cmd = VCNL_PS_EN | VCNL_PS_SELFTIMED_EN;
> +
> + rc = regmap_write(data->regmap, VCNL_COMMAND, cmd);
> + if (rc)
> + goto out_mutex;
> +
> + /*
> + * Enable interrupts on threshold, for proximity data by
> + * default.
> + */
> + rc = regmap_write(data->regmap, VCNL_PS_ICR,
> VCNL_ICR_THRES_EN);
> +
> +out_mutex:
> + mutex_unlock(&data->lock);
> +
> + return rc;
> +}
> +
> +static int vcnl3020_disable_periodic(struct iio_dev *indio_dev,
> + struct vcnl3020_data *data)
> +{
> + int rc;
> +
> + mutex_lock(&data->lock);
> +
> + rc = regmap_write(data->regmap, VCNL_COMMAND, 0);
> + if (rc)
> + goto out_mutex;
> +
> + rc = regmap_write(data->regmap, VCNL_PS_ICR, 0);
> + if (rc)
> + goto out_mutex;
> +
> + /* Clear interrupt flag bit */
> + rc = regmap_write(data->regmap, VCNL_ISR, 0);
> +
> +out_mutex:
> + mutex_unlock(&data->lock);
> +
> + return rc;
> +}
> +
> +static int vcnl3020_config_threshold(struct iio_dev *indio_dev, bool
> state)
> +{
> + struct vcnl3020_data *data = iio_priv(indio_dev);
> +
> + if (state) {
> + return vcnl3020_enable_periodic(indio_dev, data);
> + } else {
> + if (!vcnl3020_is_thr_enabled(data))
> + return 0;
> + return vcnl3020_disable_periodic(indio_dev, data);
> + }
> +}
> +
> +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_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),
> + },
> +};
> +
> 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 +466,11 @@ 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;

This does not give you any guarantee that you won't end up calling
'vcnl3020_measure_proximity()' with periodic mode enabled... The
'if()' should be done under the same data lock that you use for
enabling/disabling this mode. Just push the check inside
'vcnl3020_measure_proximity()'.

> rc = vcnl3020_measure_proximity(data, val);
> if (rc)
> return rc;
> @@ -254,6 +492,10 @@ 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;

ditto...

[1]: https://marc.info/?l=linux-kernel&m=162556231125061&w=2
- Nuno Sá

> switch (mask) {
> case IIO_CHAN_INFO_SAMP_FREQ:
> rc = iio_device_claim_direct_mode(indio_dev);
> @@ -287,6 +529,10 @@ static const struct iio_info vcnl3020_info = {
> .read_raw = vcnl3020_read_raw,
> .write_raw = vcnl3020_write_raw,
> .read_avail = vcnl3020_read_avail,
> + .read_event_value = vcnl3020_read_event,
> + .write_event_value = vcnl3020_write_event,
> + .read_event_config = vcnl3020_read_event_config,
> + .write_event_config = vcnl3020_write_event_config,
> };
>
> static const struct regmap_config vcnl3020_regmap_config = {
> @@ -295,6 +541,40 @@ static const struct regmap_config
> vcnl3020_regmap_config = {
> .max_register = VCNL_PS_MOD_ADJ,
> };
>
> +static irqreturn_t vcnl3020_handle_irq_thread(int irq, void *p)
> +{
> + struct iio_dev *indio_dev = p;
> + struct vcnl3020_data *data = iio_priv(indio_dev);
> + unsigned int isr;
> + int rc;
> +
> + rc = regmap_read(data->regmap, VCNL_ISR, &isr);
> + if (rc) {
> + dev_err(data->dev, "Error (%d) reading reg (0x%x)\n",
> + rc, VCNL_ISR);
> + return IRQ_HANDLED;
> + }
> +
> + if (isr & VCNL_ICR_THRES_EN) {
> + iio_push_event(indio_dev,
> +
> IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY,
> + 1,
> + IIO_EV_TYPE_THRESH,
> + IIO_EV_DIR_RISING),
> + iio_get_time_ns(indio_dev));
> +
> + rc = regmap_write(data->regmap, VCNL_ISR,
> + isr & VCNL_ICR_THRES_EN);
> + if (rc)
> + dev_err(data->dev, "Error (%d) writing in reg
> (0x%x)\n",
> + rc, VCNL_ISR);
> + } else {
> + return IRQ_NONE;
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> static int vcnl3020_probe(struct i2c_client *client)
> {
> struct vcnl3020_data *data;
> @@ -327,6 +607,19 @@ static int vcnl3020_probe(struct i2c_client
> *client)
> indio_dev->name = "vcnl3020";
> indio_dev->modes = INDIO_DIRECT_MODE;
>
> + if (client->irq) {
> + rc = devm_request_threaded_irq(&client->dev, client-
> >irq,
> + NULL,
> vcnl3020_handle_irq_thread,
> + IRQF_ONESHOT, indio_dev-
> >name,
> + indio_dev);
> + if (rc) {
> + dev_err(&client->dev,
> + "Error (%d) irq request failed (%u)\n",
> rc,
> + client->irq);
> + return rc;
> + }
> + }
> +
> return devm_iio_device_register(&client->dev, indio_dev);
> }
>
> --
> 2.31.1

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