Re: [PATCH v2 2/3] iio: common: cros_ec_sensors: add sysfs attribute for frequencies

From: Fabien Lahoudere
Date: Mon May 27 2019 - 05:58:31 EST


Le dimanche 26 mai 2019 Ã 18:45 +0100, Jonathan Cameron a Ãcrit :
> On Thu, 23 May 2019 11:07:36 +0200
> Fabien Lahoudere <fabien.lahoudere@xxxxxxxxxxxxx> wrote:
>
> > In order to provide minimum and maximum frequencies for each
> > sensors,
> > we use a standard API (sampling_frequency_available) to provide
> > them
> > to userland.
> > As cros_ec_sensors_core_init do not manage default attrs, we change
> > the signature to let all kind of sensors to provide "struct
> > iio_info"
> > with their callback. This change impact drivers using that
> > function.
> >
> > Then cros_ec_* sensors provides frequencies range in sysfs like
> > this:
> > [min step max]
> >
> > Signed-off-by: Fabien Lahoudere <fabien.lahoudere@xxxxxxxxxxxxx>
> When I was pointing at the _available syntax I was meaning that
> the ideal is to implement this using the associated callbacks rather
> than as a custom sysfs attribute.
>

Sorry, I misunderstood. Let me retry with that callback implemented.

> > ---
> > .../common/cros_ec_sensors/cros_ec_sensors.c | 6 +--
> > .../cros_ec_sensors/cros_ec_sensors_core.c | 38
> > +++++++++++++++++++
> > drivers/iio/light/cros_ec_light_prox.c | 6 +--
> > drivers/iio/pressure/cros_ec_baro.c | 6 +--
> > .../linux/iio/common/cros_ec_sensors_core.h | 4 +-
> > 5 files changed, 50 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c
> > b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c
> > index 17af4e0fd5f8..a0ecee15a6c8 100644
> > --- a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c
> > +++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c
> > @@ -172,7 +172,7 @@ static int cros_ec_sensors_write(struct iio_dev
> > *indio_dev,
> > return ret;
> > }
> >
> > -static const struct iio_info ec_sensors_info = {
> > +static struct iio_info ec_sensors_info = {
> > .read_raw = &cros_ec_sensors_read,
> > .write_raw = &cros_ec_sensors_write,
> > };
> > @@ -195,11 +195,11 @@ static int cros_ec_sensors_probe(struct
> > platform_device *pdev)
> > if (!indio_dev)
> > return -ENOMEM;
> >
> > - ret = cros_ec_sensors_core_init(pdev, indio_dev, true);
> > + ret = cros_ec_sensors_core_init(pdev, indio_dev,
> > &ec_sensors_info,
> > + true);
> > if (ret)
> > return ret;
> >
> > - indio_dev->info = &ec_sensors_info;
> > state = iio_priv(indio_dev);
> > for (channel = state->channels, i = CROS_EC_SENSOR_X;
> > i < CROS_EC_SENSOR_MAX_AXIS; i++, channel++) {
> > diff --git
> > a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
> > b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
> > index ac53ea32c1b1..08fb5d3dc7b5 100644
> > --- a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
> > +++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
> > @@ -10,6 +10,7 @@
> > #include <linux/iio/buffer.h>
> > #include <linux/iio/common/cros_ec_sensors_core.h>
> > #include <linux/iio/iio.h>
> > +#include <linux/iio/sysfs.h>
> > #include <linux/iio/kfifo_buf.h>
> > #include <linux/iio/trigger_consumer.h>
> > #include <linux/kernel.h>
> > @@ -86,8 +87,42 @@ static int
> > cros_ec_get_host_cmd_version_mask(struct cros_ec_device *ec_dev,
> > return ret;
> > }
> >
> > +/**
> > + * cros_ec_sensors_read_freq() - sysfs function to get available
> > frequencies
> > + * @dev: Device structure for this device.
> > + * @attr: Description of the attribute.
> > + * @buf: Incoming string
> > + *
> > + * The later modes are only relevant to the ring buffer - and
> > depend on current
> > + * mode. Note that data sheet gives rather wide tolerances for
> > these so integer
> > + * division will give good enough answer and not all chips have
> > them specified
> > + * at all.
> > + **/
> > +static ssize_t cros_ec_sensors_read_freq(struct device *dev,
> > + struct device_attribute *attr,
> > + char *buf)
> > +{
> > + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> > + struct cros_ec_sensors_core_state *state = iio_priv(indio_dev);
> > +
> > + return snprintf(buf, PAGE_SIZE, "[%d 1 %d]\n", state->min_freq,
> > + state->max_freq);
> Whilst it is a bit more fiddly I would much prefer if this was done
> with
> the info_mask_shared_by_all_available bit mask in the iio_dev and
> providing
> the read_avail callback.
>
> The original reason to introduce this form was as part of trying to
> (far too slowly) kill off as much hand defined ABI as possible.
> Ultimate aim is to make the IIO interface optional for cases where
> the channels are mostly being used by other consumer drivers rather
> than
> being directly consumed by userspace. To do that we need all of
> these elements to be easily accessible from the consumer hooks.
>
>
>
> > +}
> > +
> > +static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(cros_ec_sensors_read_freq);
> > +
> > +static struct attribute *cros_ec_sensors_attributes[] = {
> > + &iio_dev_attr_sampling_frequency_available.dev_attr.attr,
> > + NULL,
> > +};
> > +
> > +static const struct attribute_group
> > cros_ec_sensors_attribute_group = {
> > + .attrs = cros_ec_sensors_attributes,
> > +};
> > +
> > int cros_ec_sensors_core_init(struct platform_device *pdev,
> > struct iio_dev *indio_dev,
> > + struct iio_info *info,
> > bool physical_device)
> > {
> > struct device *dev = &pdev->dev;
> > @@ -149,6 +184,9 @@ int cros_ec_sensors_core_init(struct
> > platform_device *pdev,
> > }
> > }
> >
> > + info->attrs = &cros_ec_sensors_attribute_group;
> > + indio_dev->info = info;
> > +
> > return 0;
> > }
> > EXPORT_SYMBOL_GPL(cros_ec_sensors_core_init);
> > diff --git a/drivers/iio/light/cros_ec_light_prox.c
> > b/drivers/iio/light/cros_ec_light_prox.c
> > index 308ee6ff2e22..1772e339cf14 100644
> > --- a/drivers/iio/light/cros_ec_light_prox.c
> > +++ b/drivers/iio/light/cros_ec_light_prox.c
> > @@ -161,7 +161,7 @@ static int cros_ec_light_prox_write(struct
> > iio_dev *indio_dev,
> > return ret;
> > }
> >
> > -static const struct iio_info cros_ec_light_prox_info = {
> > +static struct iio_info cros_ec_light_prox_info = {
> > .read_raw = &cros_ec_light_prox_read,
> > .write_raw = &cros_ec_light_prox_write,
> > };
> > @@ -184,11 +184,11 @@ static int cros_ec_light_prox_probe(struct
> > platform_device *pdev)
> > if (!indio_dev)
> > return -ENOMEM;
> >
> > - ret = cros_ec_sensors_core_init(pdev, indio_dev, true);
> > + ret = cros_ec_sensors_core_init(pdev, indio_dev,
> > + &cros_ec_light_prox_info,
> > true);
> > if (ret)
> > return ret;
> >
> > - indio_dev->info = &cros_ec_light_prox_info;
> > state = iio_priv(indio_dev);
> > state->core.type = state->core.resp->info.type;
> > state->core.loc = state->core.resp->info.location;
> > diff --git a/drivers/iio/pressure/cros_ec_baro.c
> > b/drivers/iio/pressure/cros_ec_baro.c
> > index 034ce98d6e97..cd3be0f16226 100644
> > --- a/drivers/iio/pressure/cros_ec_baro.c
> > +++ b/drivers/iio/pressure/cros_ec_baro.c
> > @@ -107,7 +107,7 @@ static int cros_ec_baro_write(struct iio_dev
> > *indio_dev,
> > return ret;
> > }
> >
> > -static const struct iio_info cros_ec_baro_info = {
> > +static struct iio_info cros_ec_baro_info = {
> > .read_raw = &cros_ec_baro_read,
> > .write_raw = &cros_ec_baro_write,
> > };
> > @@ -130,11 +130,11 @@ static int cros_ec_baro_probe(struct
> > platform_device *pdev)
> > if (!indio_dev)
> > return -ENOMEM;
> >
> > - ret = cros_ec_sensors_core_init(pdev, indio_dev, true);
> > + ret = cros_ec_sensors_core_init(pdev, indio_dev,
> > &cros_ec_baro_info,
> > + true);
> > if (ret)
> > return ret;
> >
> > - indio_dev->info = &cros_ec_baro_info;
> > state = iio_priv(indio_dev);
> > state->core.type = state->core.resp->info.type;
> > state->core.loc = state->core.resp->info.location;
> > diff --git a/include/linux/iio/common/cros_ec_sensors_core.h
> > b/include/linux/iio/common/cros_ec_sensors_core.h
> > index 32fd08bbcf52..f170a72ac08d 100644
> > --- a/include/linux/iio/common/cros_ec_sensors_core.h
> > +++ b/include/linux/iio/common/cros_ec_sensors_core.h
> > @@ -114,12 +114,14 @@ struct platform_device;
> > * cros_ec_sensors_core_init() - basic initialization of the core
> > structure
> > * @pdev: platform device created for the sensors
> > * @indio_dev: iio device structure of the device
> > + * @info: iio info structure with read and write callback
> > * @physical_device: true if the device refers to a physical
> > device
> > *
> > * Return: 0 on success, -errno on failure.
> > */
> > int cros_ec_sensors_core_init(struct platform_device *pdev,
> > - struct iio_dev *indio_dev, bool
> > physical_device);
> > + struct iio_dev *indio_dev, struct
> > iio_info *info,
> > + bool physical_device);
> >
> > /**
> > * cros_ec_sensors_capture() - the trigger handler function