On 02/10/2014 05:17 PM, Antti Palosaari wrote:
> Modern silicon RF tuners used nowadays has many controllable gain
> stages on signal path. Usually, but not always, there is at least
> 3 gain stages. Also on some cases there could be multiple gain
> stages within the ones specified here. However, I think that having
> these three controllable gain stages offers enough fine-tuning for
> real use cases.
>
> 1) LNA gain. That is first gain just after antenna input.
> 2) Mixer gain. It is located quite middle of the signal path, where
> RF signal is down-converted to IF/BB.
> 3) IF gain. That is last gain in order to adjust output signal level
> to optimal level for receiving party (usually demodulator ADC).
>
> Each gain stage could be set rather often both manual or automatic
> (AGC) mode. Due to that add separate controls for controlling
> operation mode.
>
> Signed-off-by: Antti Palosaari <crope@xxxxxx>
> ---
> drivers/media/v4l2-core/v4l2-ctrls.c | 15 +++++++++++++++
> include/uapi/linux/v4l2-controls.h | 11 +++++++++++
> 2 files changed, 26 insertions(+)
>
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
> index 6ff002b..d201f61 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -857,6 +857,14 @@ const char *v4l2_ctrl_get_name(u32 id)
> case V4L2_CID_FM_RX_CLASS: return "FM Radio Receiver Controls";
> case V4L2_CID_TUNE_DEEMPHASIS: return "De-Emphasis";
> case V4L2_CID_RDS_RECEPTION: return "RDS Reception";
> +
> + case V4L2_CID_RF_TUNER_CLASS: return "RF Tuner Controls";
> + case V4L2_CID_LNA_GAIN_AUTO: return "LNA Gain, Auto";
> + case V4L2_CID_LNA_GAIN: return "LNA Gain";
> + case V4L2_CID_MIXER_GAIN_AUTO: return "Mixer Gain, Auto";
> + 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";
> default:
> return NULL;
> }
> @@ -906,6 +914,9 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
> case V4L2_CID_WIDE_DYNAMIC_RANGE:
> case V4L2_CID_IMAGE_STABILIZATION:
> case V4L2_CID_RDS_RECEPTION:
> + case V4L2_CID_LNA_GAIN_AUTO:
> + case V4L2_CID_MIXER_GAIN_AUTO:
> + case V4L2_CID_IF_GAIN_AUTO:
> *type = V4L2_CTRL_TYPE_BOOLEAN;
> *min = 0;
> *max = *step = 1;
> @@ -991,6 +1002,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
> case V4L2_CID_IMAGE_PROC_CLASS:
> case V4L2_CID_DV_CLASS:
> case V4L2_CID_FM_RX_CLASS:
> + case V4L2_CID_RF_TUNER_CLASS:
> *type = V4L2_CTRL_TYPE_CTRL_CLASS;
> /* You can neither read not write these */
> *flags |= V4L2_CTRL_FLAG_READ_ONLY | V4L2_CTRL_FLAG_WRITE_ONLY;
> @@ -1063,6 +1075,9 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
> case V4L2_CID_PILOT_TONE_FREQUENCY:
> case V4L2_CID_TUNE_POWER_LEVEL:
> case V4L2_CID_TUNE_ANTENNA_CAPACITOR:
> + case V4L2_CID_LNA_GAIN:
> + case V4L2_CID_MIXER_GAIN:
> + case V4L2_CID_IF_GAIN:
> *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 2cbe605..076fa34 100644
> --- a/include/uapi/linux/v4l2-controls.h
> +++ b/include/uapi/linux/v4l2-controls.h
> @@ -60,6 +60,7 @@
> #define V4L2_CTRL_CLASS_IMAGE_PROC 0x009f0000 /* Image processing controls */
> #define V4L2_CTRL_CLASS_DV 0x00a00000 /* Digital Video controls */
> #define V4L2_CTRL_CLASS_FM_RX 0x00a10000 /* FM Receiver controls */
> +#define V4L2_CTRL_CLASS_RF_TUNER 0x00a20000 /* RF tuner controls */
>
> /* User-class control IDs */
>
> @@ -895,4 +896,14 @@ enum v4l2_deemphasis {
>
> #define V4L2_CID_RDS_RECEPTION (V4L2_CID_FM_RX_CLASS_BASE + 2)
>
> +#define V4L2_CID_RF_TUNER_CLASS_BASE (V4L2_CTRL_CLASS_RF_TUNER | 0x900)
> +#define V4L2_CID_RF_TUNER_CLASS (V4L2_CTRL_CLASS_RF_TUNER | 1)
> +
> +#define V4L2_CID_LNA_GAIN_AUTO (V4L2_CID_RF_TUNER_CLASS_BASE + 1)
> +#define V4L2_CID_LNA_GAIN (V4L2_CID_RF_TUNER_CLASS_BASE + 2)
> +#define V4L2_CID_MIXER_GAIN_AUTO (V4L2_CID_RF_TUNER_CLASS_BASE + 3)
> +#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)
I would prefer to give these control defines a prefix:
V4L2_CID_RF_TUNER_MIXER_GAIN_AUTO (or possibly V4L2_CID_RF_TNR_...)
'MIXER_GAIN' by itself does not make it clear it relates to a tuner, it
might just as well refer to audio mixing or video mixing.
Thinking this over I am wondering whether these controls might not fit
just as well with the FM_RX class. Yeah, I know, the 'FM' part is a bit
unfortunate in that context, but it is about radio receivers as well.
Unless there is a good reason to keep these controls in their own class?
Regards,
Hans
> +
> #endif
>
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