Now driver returns correct values for DVB-C:
 SNR (in dB)

[mchehab@s-opensource.com: fix a new function to be static]
Signed-off-by: NAbylay Ospan <aospan@netup.ru>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

now driver returns correct values for DVB-C:
 BER (post_bit_count and post_bit_error values)
 UCB (count of uncorrected errors)
also, some code cleanup was done - checkpatch.pl now is happy
Signed-off-by: NAbylay Ospan <aospan@netup.ru>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

DVB-C should use cxd2841er_read_agc_gain_c() to get the gain. The same
function is used for all DVB-C annex delivery systems.
Signed-off-by: NAbylay Ospan <aospan@netup.ru>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

The scale for ISDB-T was wrong too: it was inverted, and
on a relative scale.

Use a linear interpolation to make it look better.
The formula was empirically determined, using 3 frequencies
(175 MHz, 410 MHz and 800 MHz), measuring from -50dBm to
-12dBm in steps of 0.5dB.
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

Instead of using a relative frequency range, calibrate it to
show the results in dB. The callibration was done getting
samples with a signal generated from -50dBm to -12dBm,
incremented in steps of 0.5 dB, using 3 frequencies:
175 MHz, 410 MHz and 800 MHz. The modulated signal was
using QAM64, and it was used a linear interpolation of all
the results.
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

Currently, there's no stats for DVB-C. Let's at least return
signal strength. The scale is different than on DVB-T, so let's
use a relative scale, for now.
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

What userspace expects is to receive both bit_error and bit_count
counters. So, instead of doing the division at the Kernel,
return the counters for userspace to handle it the way it
wants.
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

The current code will expose a zero value if one of the stats is
not available, but this is not what userspace expects. Instead,
if something goes wrong on providing some stats, it should be
changing the scale to FE_SCALE_NOT_AVAILABLE.

So, change the logic to do the right thing.
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

cxd2841er_read_agc_gain_c added to obtain signal strength.
signal strength now relay on AGC value.
Signed-off-by: NAbylay Ospan <aospan@netup.ru>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

The signal strength value is reversed: the bigger the number,
the weaker is the signal.

Fix the logic and present it in dBm. Please notice that the
dBm measure is actually an estimation, as the ratio is not
fully linear. It also varies with the frequency.

Yet, the estimation should be good enough for programs like
Kaffeine to indicate when the signal is good or bad.
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Acked-by: NAbylay Ospan <aospan@netup.ru>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

It is a good idea to measure the signal strength while
tuning, as this helps to identify if the antenna is ok.
Also, such measure helps to identify the quality of the
signal.

Do some changes to enable it before signal lock. While
here, optimize the code to only initialize the stats
length once, and make sure that, just after set_frontend,
any reading for the stats that depends on lock to return
FE_SCALE_NOT_AVAILABLE.
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Acked-by: NAbylay Ospan <aospan@netup.ru>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

correct is CXD2841ER and CXD2854ER
incorrect was CXD2441ER and CXD2454ER
Signed-off-by: NAbylay Ospan <aospan@netup.ru>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

Old behaviour:
frontend0 - DVB-S/S2
frontend1 - DVB-T/T2
frontend2 - DVB-C
frontend3 - ISDB-T

New behaviour (DVBv5 API compliant):
frontend0 - DVB-S/S2
frontend1 - DVB-T/T2/C/ISDB-T

DTV standard should be selected by DTV_DELIVERY_SYSTEM call.

And DVB-C default bandwidth now 8MHz
Signed-off-by: NAbylay Ospan <aospan@netup.ru>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

bandwidth 1.7,5,6,7,8Mhz support for DVB-T2
Signed-off-by: NAbylay Ospan <aospan@netup.ru>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

now when new tuning parameters specified demod should retune.
Also ISDB-T frequency offset calculation added
(cxd2841er_get_carrier_offset_i).

While here, fix re-tune for DVB-C Annex A, using the desired
bandwidth, instead of using 8MHz.
Signed-off-by: NAbylay Ospan <aospan@netup.ru>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

Fix offset calculation inside cxd2841er_get_carrier_offset_t
Now DVB-T should be tuned correctly
Signed-off-by: NAbylay Ospan <aospan@netup.ru>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

Avoid error message:
cxd2841er_read_status_s(): invalid state 1
Always force demod to shutdown state before initializing
Signed-off-by: NAbylay Ospan <aospan@netup.ru>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

Adding cxd2841er_get_carrier_offset_t to calculate DVB-T offset
for Sony demodulators CXD2841ER and CXD2854ER
Signed-off-by: NAbylay Ospan <aospan@netup.ru>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

CXD2854ER is identical to CXD2841ER except ISDB-T/S added.
New method 'cxd2841er_attach_i' is added
xtal frequency now configurable. Available options:
20.5MHz, 24MHz, 41MHz
Signed-off-by: NAbylay Ospan <aospan@netup.ru>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

Instead of using the DTV properties cache directly, pass the get
frontend data as an argument. For now, everything should remain
the same, but the next patch will prevent get_frontend to
affect the global cache.

This is needed because several drivers don't care enough to only
change the properties if locked. Due to that, calling
G_PROPERTY before locking on those drivers will make them to
never lock. Ok, those drivers are crap and should never be
merged like that, but the core should not rely that the drivers
would be doing the right thing.
Reviewed-by: NMichael Ira Krufky <mkrufky@linuxtv.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

The Linux stack is short; we need to be able to count the number
of bytes used at stack on each function. So, we don't like to
use variable-length arrays, as complained by smatch:

	drivers/media/dvb-frontends/cxd2841er.c:205:19: warning: Variable length array is used.

The max usecase of the driver seems to be 15 bytes + 1 for the
register.

So, let's be safe and allocate 17 bytes for the write buffer.
This should be enough to cover all cases. If not, let's print
an error message.
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/dvb-frontends/cxd2841er.c:992:5: warning: no previous prototype for 'cxd2841er_get_carrier_offset_t2' [-Wmissing-prototypes]
 int cxd2841er_get_carrier_offset_t2(
     ^
drivers/media/dvb-frontends/cxd2841er.c:1032:5: warning: no previous prototype for 'cxd2841er_get_carrier_offset_c' [-Wmissing-prototypes]
 int cxd2841er_get_carrier_offset_c(
     ^
drivers/media/dvb-frontends/cxd2841er.c:1360:5: warning: no previous prototype for 'cxd2841er_read_snr_t2' [-Wmissing-prototypes]
 int cxd2841er_read_snr_t2(struct cxd2841er_priv *priv, u32 *snr)
     ^
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

Add DVB-C/T/T2/S/S2 demodulator frontend driver Sony CXD2841ER chip.
Signed-off-by: NKozlov Sergey <serjk@netup.ru>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>