Re: PATCH: Query DVB frontend capabilities

[Andreas Oberritter <obi@linuxtv.org>]

On 11.11.2011 07:26, Manu Abraham wrote:
> diff -r b6eb04718aa9 linux/drivers/media/dvb/dvb-core/dvb_frontend.c
> --- a/linux/drivers/media/dvb/dvb-core/dvb_frontend.c	Wed Nov 09 19:52:36 2011 +0530
> +++ b/linux/drivers/media/dvb/dvb-core/dvb_frontend.c	Fri Nov 11 06:05:40 2011 +0530
> @@ -973,6 +973,8 @@
>  	_DTV_CMD(DTV_GUARD_INTERVAL, 0, 0),
>  	_DTV_CMD(DTV_TRANSMISSION_MODE, 0, 0),
>  	_DTV_CMD(DTV_HIERARCHY, 0, 0),
> +
> +	_DTV_CMD(DTV_DELIVERY_CAPS, 0, 0),
>  };
>  
>  static void dtv_property_dump(struct dtv_property *tvp)
> @@ -1226,7 +1228,11 @@
>  		c = &cdetected;
>  	}
>  
> +	dprintk("%s\n", __func__);
> +
>  	switch(tvp->cmd) {
> +	case DTV_DELIVERY_CAPS:

It would be nice to have a default implementation inserted at this point, e.g. something like:

static void dtv_set_default_delivery_caps(const struct dvb_frontend *fe, struct dtv_property *p)
{
	const struct dvb_frontend_info *info = &fe->ops.info;
	u32 ncaps = 0;

	switch (info->type) {
	case FE_QPSK:
		p->u.buffer.data[ncaps++] = SYS_DVBS;
		if (info->caps & FE_CAN_2G_MODULATION)
			p->u.buffer.data[ncaps++] = SYS_DVBS2;
		if (info->caps & FE_CAN_TURBO_FEC)
			p->u.buffer.data[ncaps++] = SYS_TURBO;
		break;
	case FE_QAM:
		p->u.buffer.data[ncaps++] = SYS_DVBC_ANNEX_AC;
		break;
	case FE_OFDM:
		p->u.buffer.data[ncaps++] = SYS_DVBT;
		if (info->caps & FE_CAN_2G_MODULATION)
			p->u.buffer.data[ncaps++] = SYS_DVBT2;
		break;
	case FE_ATSC:
		if (info->caps & (FE_CAN_8VSB | FE_CAN_16VSB))
			p->u.buffer.data[ncaps++] = SYS_ATSC;
		if (info->caps & (FE_CAN_QAM_16 | FE_CAN_QAM_64 | FE_CAN_QAM_128 | FE_CAN_QAM_256))
			p->u.buffer.data[ncaps++] = SYS_DVBC_ANNEX_B;
	}

	p->u.buffer.len = ncaps;
}

I think this would be sufficient for a lot of drivers and would thus save a lot of work.

> +		break;
>  	case DTV_FREQUENCY:
>  		tvp->u.data = c->frequency;
>  		break;
> @@ -1350,7 +1356,7 @@
>  		if (r < 0)
>  			return r;
>  	}
> -
> +done:

This label is unused now and should be removed.

>  	dtv_property_dump(tvp);
>  
>  	return 0;
> diff -r b6eb04718aa9 linux/drivers/media/dvb/frontends/stb0899_drv.c
> --- a/linux/drivers/media/dvb/frontends/stb0899_drv.c	Wed Nov 09 19:52:36 2011 +0530
> +++ b/linux/drivers/media/dvb/frontends/stb0899_drv.c	Fri Nov 11 06:05:40 2011 +0530
> @@ -1605,6 +1605,22 @@
>  	return DVBFE_ALGO_CUSTOM;
>  }
>  
> +static int stb0899_get_property(struct dvb_frontend *fe, struct dtv_property *p)
> +{
> +	switch (p->cmd) {
> +	case DTV_DELIVERY_CAPS:
> +		p->u.buffer.data[0] = SYS_DSS;
> +		p->u.buffer.data[1] = SYS_DVBS;
> +		p->u.buffer.data[2] = SYS_DVBS2;
> +		p->u.buffer.len = 3;
> +		break;
> +	default:
> +		return -EINVAL;

You should ignore all unhandled properties. Otherwise all properties handled
by the core will have result set to -EINVAL.

> +	}
> +	return 0;
> +}
> +
> +
>  static struct dvb_frontend_ops stb0899_ops = {
>  
>  	.info = {
> @@ -1647,6 +1663,8 @@
>  	.diseqc_send_master_cmd		= stb0899_send_diseqc_msg,
>  	.diseqc_recv_slave_reply	= stb0899_recv_slave_reply,
>  	.diseqc_send_burst		= stb0899_send_diseqc_burst,
> +
> +	.get_property			= stb0899_get_property,
>  };
>  
>  struct dvb_frontend *stb0899_attach(struct stb0899_config *config, struct i2c_adapter *i2c)
> diff -r b6eb04718aa9 linux/include/linux/dvb/frontend.h
> --- a/linux/include/linux/dvb/frontend.h	Wed Nov 09 19:52:36 2011 +0530
> +++ b/linux/include/linux/dvb/frontend.h	Fri Nov 11 06:05:40 2011 +0530
> @@ -316,7 +316,9 @@
>  
>  #define DTV_DVBT2_PLP_ID	43
>  
> -#define DTV_MAX_COMMAND				DTV_DVBT2_PLP_ID
> +#define DTV_DELIVERY_CAPS	44
> +
> +#define DTV_MAX_COMMAND				DTV_DELIVERY_CAPS
>  
>  typedef enum fe_pilot {
>  	PILOT_ON,
>