On Thu, Jan 4, 2018 at 7:04 PM, Brad Love <brad@xxxxxxxxxxxxxxxx> wrote:
> As configured currently, modulation in the driver is set to auto detect,
> no matter what the user sets modulation to. This leads to both QAM64
> and QAM256 having the same effect. QAM AUTO is explicitly added here for
> compatibility with scanning software who can use AUTO instead of doing
> essentially the same scan twice.
> Also included is a module option to enforce a specific QAM modulation if
> desired. The true modulation is read before calculating the snr.
> Changes are backwards compatible with current behaviour.
>
> Signed-off-by: Brad Love <brad@xxxxxxxxxxxxxxxx>
:+1
Reviewed-by: Michael Ira Krufky <mkrufky@xxxxxxxxxxx>
> ---
> drivers/media/dvb-frontends/lgdt3306a.c | 42 ++++++++++++++++++++++++++-------
> 1 file changed, 33 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/media/dvb-frontends/lgdt3306a.c b/drivers/media/dvb-frontends/lgdt3306a.c
> index 2f540f1..111efb0 100644
> --- a/drivers/media/dvb-frontends/lgdt3306a.c
> +++ b/drivers/media/dvb-frontends/lgdt3306a.c
> @@ -30,6 +30,17 @@ static int debug;
> module_param(debug, int, 0644);
> MODULE_PARM_DESC(debug, "set debug level (info=1, reg=2 (or-able))");
>
> +/*
> + * Older drivers treated QAM64 and QAM256 the same; that is the HW always
> + * used "Auto" mode during detection. Setting "forced_manual"=1 allows
> + * the user to treat these modes as separate. For backwards compatibility,
> + * it's off by default. QAM_AUTO can now be specified to achive that
> + * effect even if "forced_manual"=1
> + */
> +static int forced_manual;
> +module_param(forced_manual, int, 0644);
> +MODULE_PARM_DESC(forced_manual, "if set, QAM64 and QAM256 will only lock to modulation specified");
> +
> #define DBG_INFO 1
> #define DBG_REG 2
> #define DBG_DUMP 4 /* FGR - comment out to remove dump code */
> @@ -566,7 +577,12 @@ static int lgdt3306a_set_qam(struct lgdt3306a_state *state, int modulation)
> /* 3. : 64QAM/256QAM detection(manual, auto) */
> ret = lgdt3306a_read_reg(state, 0x0009, &val);
> val &= 0xfc;
> - val |= 0x02; /* STDOPDETCMODE[1:0]=1=Manual 2=Auto */
> + /* Check for forced Manual modulation modes; otherwise always "auto" */
> + if(forced_manual && (modulation != QAM_AUTO)){
> + val |= 0x01; /* STDOPDETCMODE[1:0]= 1=Manual */
> + } else {
> + val |= 0x02; /* STDOPDETCMODE[1:0]= 2=Auto */
> + }
> ret = lgdt3306a_write_reg(state, 0x0009, val);
> if (lg_chkerr(ret))
> goto fail;
> @@ -642,10 +658,9 @@ static int lgdt3306a_set_modulation(struct lgdt3306a_state *state,
> ret = lgdt3306a_set_vsb(state);
> break;
> case QAM_64:
> - ret = lgdt3306a_set_qam(state, QAM_64);
> - break;
> case QAM_256:
> - ret = lgdt3306a_set_qam(state, QAM_256);
> + case QAM_AUTO:
> + ret = lgdt3306a_set_qam(state, p->modulation);
> break;
> default:
> return -EINVAL;
> @@ -672,6 +687,7 @@ static int lgdt3306a_agc_setup(struct lgdt3306a_state *state,
> break;
> case QAM_64:
> case QAM_256:
> + case QAM_AUTO:
> break;
> default:
> return -EINVAL;
> @@ -726,6 +742,7 @@ static int lgdt3306a_spectral_inversion(struct lgdt3306a_state *state,
> break;
> case QAM_64:
> case QAM_256:
> + case QAM_AUTO:
> /* Auto ok for QAM */
> ret = lgdt3306a_set_inversion_auto(state, 1);
> break;
> @@ -749,6 +766,7 @@ static int lgdt3306a_set_if(struct lgdt3306a_state *state,
> break;
> case QAM_64:
> case QAM_256:
> + case QAM_AUTO:
> if_freq_khz = state->cfg->qam_if_khz;
> break;
> default:
> @@ -1607,6 +1625,7 @@ static int lgdt3306a_read_status(struct dvb_frontend *fe,
> switch (state->current_modulation) {
> case QAM_256:
> case QAM_64:
> + case QAM_AUTO:
> if (lgdt3306a_qam_lock_poll(state) == LG3306_LOCK) {
> *status |= FE_HAS_VITERBI;
> *status |= FE_HAS_SYNC;
> @@ -1650,6 +1669,7 @@ static int lgdt3306a_read_signal_strength(struct dvb_frontend *fe,
> * Calculate some sort of "strength" from SNR
> */
> struct lgdt3306a_state *state = fe->demodulator_priv;
> + u8 val;
> u16 snr; /* snr_x10 */
> int ret;
> u32 ref_snr; /* snr*100 */
> @@ -1662,11 +1682,15 @@ static int lgdt3306a_read_signal_strength(struct dvb_frontend *fe,
> ref_snr = 1600; /* 16dB */
> break;
> case QAM_64:
> - ref_snr = 2200; /* 22dB */
> - break;
> case QAM_256:
> - ref_snr = 2800; /* 28dB */
> - break;
> + case QAM_AUTO:
> + /* need to know actual modulation to set proper SNR baseline */
> + lgdt3306a_read_reg(state, 0x00a6, &val);
> + if(val & 0x04)
> + ref_snr = 2800; /* QAM-256 28dB */
> + else
> + ref_snr = 2200; /* QAM-64 22dB */
> + break;
> default:
> return -EINVAL;
> }
> @@ -2136,7 +2160,7 @@ static const struct dvb_frontend_ops lgdt3306a_ops = {
> .frequency_min = 54000000,
> .frequency_max = 858000000,
> .frequency_stepsize = 62500,
> - .caps = FE_CAN_QAM_64 | FE_CAN_QAM_256 | FE_CAN_8VSB
> + .caps = FE_CAN_QAM_AUTO | FE_CAN_QAM_64 | FE_CAN_QAM_256 | FE_CAN_8VSB
> },
> .i2c_gate_ctrl = lgdt3306a_i2c_gate_ctrl,
> .init = lgdt3306a_init,
> --
> 2.7.4
>
