Re: [REVIEW PATCH 2/6] v4l: add RF tuner channel bandwidth control

[Hans Verkuil <hverkuil@xs4all.nl>]

On 02/10/2014 05:17 PM, Antti Palosaari wrote:
> Modern silicon RF tuners has one or more adjustable filters on
> signal path, in order to filter noise from desired radio channel.
> 
> Add channel bandwidth control to tell the driver which is radio
> channel width we want receive. Filters could be then adjusted by
> the driver or hardware, using RF frequency and channel bandwidth
> as a base of filter calculations.
> 
> On automatic mode (normal mode), bandwidth is calculated from sampling
> rate or tuning info got from userspace. That new control gives
> possibility to set manual mode and let user have more control for
> filters.
> 
> Cc: Hans Verkuil <hverkuil@xs4all.nl>
> Signed-off-by: Antti Palosaari <crope@iki.fi>
> ---
>  drivers/media/v4l2-core/v4l2-ctrls.c | 4 ++++
>  include/uapi/linux/v4l2-controls.h   | 2 ++
>  2 files changed, 6 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
> index d201f61..e44722b 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -865,6 +865,8 @@ const char *v4l2_ctrl_get_name(u32 id)
>  	case V4L2_CID_MIXER_GAIN:		return "Mixer Gain";
>  	case V4L2_CID_IF_GAIN_AUTO:		return "IF Gain, Auto";
>  	case V4L2_CID_IF_GAIN:			return "IF Gain";
> +	case V4L2_CID_BANDWIDTH_AUTO:		return "Channel Bandwidth, Auto";
> +	case V4L2_CID_BANDWIDTH:		return "Channel Bandwidth";
>  	default:
>  		return NULL;
>  	}
> @@ -917,6 +919,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
>  	case V4L2_CID_LNA_GAIN_AUTO:
>  	case V4L2_CID_MIXER_GAIN_AUTO:
>  	case V4L2_CID_IF_GAIN_AUTO:
> +	case V4L2_CID_BANDWIDTH_AUTO:
>  		*type = V4L2_CTRL_TYPE_BOOLEAN;
>  		*min = 0;
>  		*max = *step = 1;
> @@ -1078,6 +1081,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
>  	case V4L2_CID_LNA_GAIN:
>  	case V4L2_CID_MIXER_GAIN:
>  	case V4L2_CID_IF_GAIN:
> +	case V4L2_CID_BANDWIDTH:
>  		*flags |= V4L2_CTRL_FLAG_SLIDER;
>  		break;
>  	case V4L2_CID_PAN_RELATIVE:
> diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
> index 076fa34..3cf68a6 100644
> --- a/include/uapi/linux/v4l2-controls.h
> +++ b/include/uapi/linux/v4l2-controls.h
> @@ -905,5 +905,7 @@ enum v4l2_deemphasis {
>  #define V4L2_CID_MIXER_GAIN			(V4L2_CID_RF_TUNER_CLASS_BASE + 4)
>  #define V4L2_CID_IF_GAIN_AUTO			(V4L2_CID_RF_TUNER_CLASS_BASE + 5)
>  #define V4L2_CID_IF_GAIN			(V4L2_CID_RF_TUNER_CLASS_BASE + 6)
> +#define V4L2_CID_BANDWIDTH_AUTO			(V4L2_CID_RF_TUNER_CLASS_BASE + 7)
> +#define V4L2_CID_BANDWIDTH			(V4L2_CID_RF_TUNER_CLASS_BASE + 8)

This definitely needs a prefix. Bandwidth can refer to so many things that
we have to be clear here.

	Hans

>  
>  #endif
>