Re: [PATCH v3 07/11] iio: add reference to iio buffer on iio_dev_attr

From: Jonathan Cameron
Date: Thu Feb 04 2021 - 13:17:30 EST

On Mon, 1 Feb 2021 16:51:01 +0200
Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> wrote:

> This change adds a reference to a 'struct iio_buffer' object on the
> iio_dev_attr object. This way, we can use the created iio_dev_attr objects
> on per-buffer basis (since they're allocated anyway).
>
> A minor downside of this change is that the number of parameters on
> __iio_add_chan_devattr() grows by 1. This looks like it could do with a bit
> of a re-think.

Could use a bit of macro magic or static inline to keep the old
version set of parameter and have __iio_add_chan_devattr_with_buf
or similar. I'm not sure I'd bother given we don't have that many callers.

>
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
> ---
> drivers/iio/iio_core.h | 2 ++
> drivers/iio/industrialio-buffer.c | 4 ++++
> drivers/iio/industrialio-core.c | 6 ++++++
> drivers/iio/industrialio-event.c | 1 +
> include/linux/iio/sysfs.h | 3 +++
> 5 files changed, 16 insertions(+)
>
> diff --git a/drivers/iio/iio_core.h b/drivers/iio/iio_core.h
> index 7d5b179c1fe7..731f5170d5b9 100644
> --- a/drivers/iio/iio_core.h
> +++ b/drivers/iio/iio_core.h
> @@ -12,6 +12,7 @@
> #include <linux/kernel.h>
> #include <linux/device.h>
>
> +struct iio_buffer;
> struct iio_chan_spec;
> struct iio_dev;
>
> @@ -43,6 +44,7 @@ int __iio_add_chan_devattr(const char *postfix,
> u64 mask,
> enum iio_shared_by shared_by,
> struct device *dev,
> + struct iio_buffer *buffer,
> struct list_head *attr_list);
> void iio_free_chan_devattr_list(struct list_head *attr_list);
>
> diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
> index f82decf92b7c..a525e88b302f 100644
> --- a/drivers/iio/industrialio-buffer.c
> +++ b/drivers/iio/industrialio-buffer.c

> @@ -447,6 +447,7 @@ static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
> 0,
> IIO_SEPARATE,
> &indio_dev->dev,
> + buffer,
> &buffer->scan_el_dev_attr_list);
> if (ret)
> return ret;
> @@ -458,6 +459,7 @@ static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
> 0,
> 0,
> &indio_dev->dev,
> + buffer,
> &buffer->scan_el_dev_attr_list);
> if (ret)
> return ret;
> @@ -470,6 +472,7 @@ static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
> chan->scan_index,
> 0,
> &indio_dev->dev,
> + buffer,
> &buffer->scan_el_dev_attr_list);
> else
> ret = __iio_add_chan_devattr("en",
> @@ -479,6 +482,7 @@ static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
> chan->scan_index,
> 0,
> &indio_dev->dev,
> + buffer,
> &buffer->scan_el_dev_attr_list);
> if (ret)
> return ret;
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index ccd7aaff6d13..c68130885d83 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -1114,6 +1114,7 @@ int __iio_add_chan_devattr(const char *postfix,
> u64 mask,
> enum iio_shared_by shared_by,
> struct device *dev,
> + struct iio_buffer *buffer,
> struct list_head *attr_list)
> {
> int ret;
> @@ -1129,6 +1130,7 @@ int __iio_add_chan_devattr(const char *postfix,
> goto error_iio_dev_attr_free;
> iio_attr->c = chan;
> iio_attr->address = mask;
> + iio_attr->buffer = buffer;
> list_for_each_entry(t, attr_list, l)
> if (strcmp(t->dev_attr.attr.name,
> iio_attr->dev_attr.attr.name) == 0) {
> @@ -1165,6 +1167,7 @@ static int iio_device_add_channel_label(struct iio_dev *indio_dev,
> 0,
> IIO_SEPARATE,
> &indio_dev->dev,
> + NULL,
> &iio_dev_opaque->channel_attr_list);
> if (ret < 0)
> return ret;
> @@ -1190,6 +1193,7 @@ static int iio_device_add_info_mask_type(struct iio_dev *indio_dev,
> i,
> shared_by,
> &indio_dev->dev,
> + NULL,
> &iio_dev_opaque->channel_attr_list);
> if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
> continue;
> @@ -1226,6 +1230,7 @@ static int iio_device_add_info_mask_type_avail(struct iio_dev *indio_dev,
> i,
> shared_by,
> &indio_dev->dev,
> + NULL,
> &iio_dev_opaque->channel_attr_list);
> kfree(avail_postfix);
> if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
> @@ -1322,6 +1327,7 @@ static int iio_device_add_channel_sysfs(struct iio_dev *indio_dev,
> i,
> ext_info->shared,
> &indio_dev->dev,
> + NULL,
> &iio_dev_opaque->channel_attr_list);
> i++;
> if (ret == -EBUSY && ext_info->shared)
> diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c
> index ea8947cc21e4..a30e289fc362 100644
> --- a/drivers/iio/industrialio-event.c
> +++ b/drivers/iio/industrialio-event.c
> @@ -385,6 +385,7 @@ static int iio_device_add_event(struct iio_dev *indio_dev,
>
> ret = __iio_add_chan_devattr(postfix, chan, show, store,
> (i << 16) | spec_index, shared_by, &indio_dev->dev,
> + NULL,
> &iio_dev_opaque->event_interface->dev_attr_list);
> kfree(postfix);
>
> diff --git a/include/linux/iio/sysfs.h b/include/linux/iio/sysfs.h
> index b532c875bc24..e51fba66de4b 100644
> --- a/include/linux/iio/sysfs.h
> +++ b/include/linux/iio/sysfs.h
> @@ -9,6 +9,7 @@
> #ifndef _INDUSTRIAL_IO_SYSFS_H_
> #define _INDUSTRIAL_IO_SYSFS_H_
>
> +struct iio_buffer;
> struct iio_chan_spec;
>
> /**
> @@ -17,12 +18,14 @@ struct iio_chan_spec;
> * @address: associated register address
> * @l: list head for maintaining list of dynamically created attrs
> * @c: specification for the underlying channel
> + * @buffer: the IIO buffer to which this attribute belongs to (if any)
> */
> struct iio_dev_attr {
> struct device_attribute dev_attr;
> u64 address;
> struct list_head l;
> struct iio_chan_spec const *c;
> + struct iio_buffer *buffer;
> };
>
> #define to_iio_dev_attr(_dev_attr) \