Re: [PATCH v3 1/2] counter: add support for Quadrature x4 with swapped inputs

[William Breathitt Gray <vilhelm.gray@gmail.com>]

On Tue, Oct 01, 2019 at 12:32:36PM +0300, Felipe Balbi wrote:
> Some Quadrature Encoders can swap phase inputs A and B
> internally. This new function will allow drivers to configure input
> swap mode.
> 
> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
> ---
>  Documentation/ABI/testing/sysfs-bus-counter | 4 ++++
>  drivers/counter/counter.c                   | 3 ++-
>  include/linux/counter.h                     | 3 ++-
>  3 files changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
> index 566bd99fe0a5..8f1e3de88c77 100644
> --- a/Documentation/ABI/testing/sysfs-bus-counter
> +++ b/Documentation/ABI/testing/sysfs-bus-counter
> @@ -146,6 +146,10 @@ Description:
>  			updates	the respective count. Quadrature encoding
>  			determines the direction.
>  
> +		quadrature x4 swapped:
> +			Same as quadrature x4, however Phase A and Phase B
> +			signals are swapped.
> +
>  What:		/sys/bus/counter/devices/counterX/countY/name
>  KernelVersion:	5.2
>  Contact:	linux-iio@vger.kernel.org

Thank you for adding an entry for this in the Counter sysfs interface
documentation file. Make a similar addition to the Counter driver API
documentation in the Documentation/driver-api/generic-counter.rst file.

> diff --git a/drivers/counter/counter.c b/drivers/counter/counter.c
> index 106bc7180cd8..b818ae9e85f2 100644
> --- a/drivers/counter/counter.c
> +++ b/drivers/counter/counter.c
> @@ -823,7 +823,8 @@ static const char *const counter_count_function_str[] = {
>  	[COUNTER_COUNT_FUNCTION_QUADRATURE_X1_B] = "quadrature x1 b",
>  	[COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A] = "quadrature x2 a",
>  	[COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B] = "quadrature x2 b",
> -	[COUNTER_COUNT_FUNCTION_QUADRATURE_X4] = "quadrature x4"
> +	[COUNTER_COUNT_FUNCTION_QUADRATURE_X4] = "quadrature x4",
> +	[COUNTER_COUNT_FUNCTION_QUADRATURE_X4_SWAPPED] = "quadrature x4 swapped"

Add a comma to the end of this line so that we don't have to change it
if we add another function mode in the future.

William Breathitt Gray

>  };
>  
>  static ssize_t counter_function_show(struct device *dev,
> diff --git a/include/linux/counter.h b/include/linux/counter.h
> index a061cdcdef7c..860769250f89 100644
> --- a/include/linux/counter.h
> +++ b/include/linux/counter.h
> @@ -170,7 +170,8 @@ enum counter_count_function {
>  	COUNTER_COUNT_FUNCTION_QUADRATURE_X1_B,
>  	COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
>  	COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B,
> -	COUNTER_COUNT_FUNCTION_QUADRATURE_X4
> +	COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
> +	COUNTER_COUNT_FUNCTION_QUADRATURE_X4_SWAPPED,
>  };
>  
>  /**
> -- 
> 2.23.0
>