Re: [PATCH v6 05/16] iio: core: support 64-bit register through debugfs

["Nuno Sá" <noname.nuno@gmail.com>]

On Thu, Jun 18, 2026 at 02:27:21PM +0100, Rodrigo Alencar via B4 Relay wrote:
> From: Rodrigo Alencar <rodrigo.alencar@analog.com>
> 
> Add debugfs_reg64_access function pointer field into iio_info and modify
> file operation callbacks to favor 64-bit variant when it is available.
> 
> Signed-off-by: Rodrigo Alencar <rodrigo.alencar@analog.com>
> ---
>  drivers/iio/industrialio-core.c | 33 ++++++++++++++++++++++++---------
>  include/linux/iio/iio-opaque.h  |  2 +-
>  include/linux/iio/iio.h         |  4 ++++
>  3 files changed, 29 insertions(+), 10 deletions(-)
> 
> @@ -471,7 +485,8 @@ static void iio_device_register_debugfs(struct iio_dev *indio_dev)
>  {
>  	struct iio_dev_opaque *iio_dev_opaque;
>  
> -	if (indio_dev->info->debugfs_reg_access == NULL)
> +	if (!indio_dev->info->debugfs_reg_access &&
> +	    !indio_dev->info->debugfs_reg64_access)
>  		return;

Not really that important but should dev_warn() in case someone gives
both callbacks? Can't use both anyways.

(We now have agentic help reviewing the code so maybe even if someone
does it for some reason it won't pass review :))

- Nuno Sá
>  
>  	if (!iio_debugfs_dentry)
> diff --git a/include/linux/iio/iio-opaque.h b/include/linux/iio/iio-opaque.h
> index b87841a355f8..98330385e08d 100644
> --- a/include/linux/iio/iio-opaque.h
> +++ b/include/linux/iio/iio-opaque.h
> @@ -73,7 +73,7 @@ struct iio_dev_opaque {
>  #if defined(CONFIG_DEBUG_FS)
>  	struct dentry			*debugfs_dentry;
>  	unsigned int			cached_reg_addr;
> -	char				read_buf[20];
> +	char				read_buf[24];
>  	unsigned int			read_buf_len;
>  #endif
>  };
> diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
> index 711c00f67371..1c7d12af22da 100644
> --- a/include/linux/iio/iio.h
> +++ b/include/linux/iio/iio.h
> @@ -484,6 +484,7 @@ struct iio_trigger; /* forward declaration */
>   * @update_scan_mode:	function to configure device and scan buffer when
>   *			channels have changed
>   * @debugfs_reg_access:	function to read or write register value of device
> + * @debugfs_reg64_access: function to read or write 64-bit register value of device
>   * @fwnode_xlate:	fwnode based function pointer to obtain channel specifier index.
>   * @hwfifo_set_watermark: function pointer to set the current hardware
>   *			fifo watermark level; see hwfifo_* entries in
> @@ -572,6 +573,9 @@ struct iio_info {
>  	int (*debugfs_reg_access)(struct iio_dev *indio_dev,
>  				  unsigned int reg, unsigned int writeval,
>  				  unsigned int *readval);
> +	int (*debugfs_reg64_access)(struct iio_dev *indio_dev,
> +				    unsigned int reg, u64 writeval,
> +				    u64 *readval);
>  	int (*fwnode_xlate)(struct iio_dev *indio_dev,
>  			    const struct fwnode_reference_args *iiospec);
>  	int (*hwfifo_set_watermark)(struct iio_dev *indio_dev, unsigned int val);
> 
> -- 
> 2.43.0
> 
>