[PATCH v12 14/17] counter: Implement *_component_id sysfs attributes

[David Lechner]

On 7/5/21 3:19 AM, William Breathitt Gray wrote:
> The Generic Counter chrdev interface expects users to supply component
> IDs in order to select extensions for requests. In order for users to
> know what component ID belongs to which extension this information must
> be exposed. The *_component_id attribute provides a way for users to
> discover what component ID belongs to which respective extension.
> 
> Cc: David Lechner <david at lechnology.com>
> Cc: Gwendal Grignou <gwendal at chromium.org>
> Cc: Dan Carpenter <dan.carpenter at oracle.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray at gmail.com>
> ---
>   Documentation/ABI/testing/sysfs-bus-counter | 16 ++++++++++-
>   drivers/counter/counter-sysfs.c             | 30 ++++++++++++++++-----
>   2 files changed, 39 insertions(+), 7 deletions(-)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
> index 9809d8a47431..e0e99adb0ecc 100644
> --- a/Documentation/ABI/testing/sysfs-bus-counter
> +++ b/Documentation/ABI/testing/sysfs-bus-counter
> @@ -203,12 +203,26 @@ Description:
>   		both edges:
>   			Any state transition.
>   
> +What:		/sys/bus/counter/devices/counterX/countY/ceiling_component_id
> +What:		/sys/bus/counter/devices/counterX/countY/floor_component_id
> +What:		/sys/bus/counter/devices/counterX/countY/count_mode_component_id
> +What:		/sys/bus/counter/devices/counterX/countY/direction_component_id
> +What:		/sys/bus/counter/devices/counterX/countY/enable_component_id
> +What:		/sys/bus/counter/devices/counterX/countY/error_noise_component_id
> +What:		/sys/bus/counter/devices/counterX/countY/prescaler_component_id
> +What:		/sys/bus/counter/devices/counterX/countY/preset_component_id
> +What:		/sys/bus/counter/devices/counterX/countY/preset_enable_component_id
>   What:		/sys/bus/counter/devices/counterX/countY/signalZ_action_component_id
> +What:		/sys/bus/counter/devices/counterX/signalY/cable_fault_component_id
> +What:		/sys/bus/counter/devices/counterX/signalY/cable_fault_enable_component_id
> +What:		/sys/bus/counter/devices/counterX/signalY/filter_clock_prescaler_component_id
> +What:		/sys/bus/counter/devices/counterX/signalY/index_polarity_component_id
> +What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode_component_id

Could we just write a single line?

What:		/sys/bus/counter/devices/counterX/signalY/<component>_component_id

>   KernelVersion:	5.15
>   Contact:	linux-iio at vger.kernel.org
>   Description:
>   		Read-only attribute that indicates the component ID of the
> -		respective Synapse of Count Y for Signal Z.
> +		respective extension or Synapse.
>   
>   What:		/sys/bus/counter/devices/counterX/countY/spike_filter_ns
>   KernelVersion:	5.14
> diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c
> index bb49a10f160b..eb1505bfbd89 100644
> --- a/drivers/counter/counter-sysfs.c
> +++ b/drivers/counter/counter-sysfs.c
> @@ -587,6 +587,7 @@ static int counter_signal_attrs_create(struct counter_device *const counter,
>   	int err;
>   	struct counter_comp comp;
>   	size_t i;
> +	struct counter_comp *ext;
>   
>   	/* Create main Signal attribute */
>   	comp = counter_signal_comp;
> @@ -602,8 +603,13 @@ static int counter_signal_attrs_create(struct counter_device *const counter,
>   
>   	/* Create an attribute for each extension */
>   	for (i = 0; i < signal->num_ext; i++) {
> -		err = counter_attr_create(dev, group, signal->ext + i, scope,
> -					  signal);
> +		ext = signal->ext + i;
> +
> +		err = counter_attr_create(dev, group, ext, scope, signal);
> +		if (err < 0)
> +			return err;
> +
> +		err = counter_comp_id_attr_create(dev, group, ext->name, i);
>   		if (err < 0)
>   			return err;
>   	}
> @@ -694,6 +700,7 @@ static int counter_count_attrs_create(struct counter_device *const counter,
>   	int err;
>   	struct counter_comp comp;
>   	size_t i;
> +	struct counter_comp *ext;
>   
>   	/* Create main Count attribute */
>   	comp = counter_count_comp;
> @@ -718,8 +725,13 @@ static int counter_count_attrs_create(struct counter_device *const counter,
>   
>   	/* Create an attribute for each extension */
>   	for (i = 0; i < count->num_ext; i++) {
> -		err = counter_attr_create(dev, group, count->ext + i, scope,
> -					  count);
> +		ext = count->ext + i;

		ext = &count->ext[i];

Could make it more clear we are dealing with pointers rather than integers.

> +
> +		err = counter_attr_create(dev, group, ext, scope, count);
> +		if (err < 0)
> +			return err;
> +
> +		err = counter_comp_id_attr_create(dev, group, ext->name, i);
>   		if (err < 0)
>   			return err;
>   	}
> @@ -783,6 +795,7 @@ static int counter_sysfs_attr_add(struct counter_device *const counter,
>   	struct device *const dev = &counter->dev;
>   	int err;
>   	size_t i;
> +	struct counter_comp *ext;
>   
>   	/* Add Signals sysfs attributes */
>   	err = counter_sysfs_signals_add(counter, group);
> @@ -815,8 +828,13 @@ static int counter_sysfs_attr_add(struct counter_device *const counter,
>   
>   	/* Create an attribute for each extension */
>   	for (i = 0; i < counter->num_ext; i++) {
> -		err = counter_attr_create(dev, group, counter->ext + i, scope,
> -					  NULL);
> +		ext = counter->ext + i;

ditto

> +
> +		err = counter_attr_create(dev, group, ext, scope, NULL);
> +		if (err < 0)
> +			return err;
> +
> +		err = counter_comp_id_attr_create(dev, group, ext->name, i);
>   		if (err < 0)
>   			return err;
>   	}
>