linux-toradex.git/drivers/media/dvb-frontends/ts2020.c, branch v4.4.156

media: ts2020: avoid integer overflows on 32 bit machines

2018-02-16T19:09:45+00:00

commit 81742be14b6a90c9fd0ff6eb4218bdf696ad8e46 upstream.

Before this patch, when compiled for arm32, the signal strength
were reported as:

Lock   (0x1f) Signal= 4294908.66dBm C/N= 12.79dB

Because of a 32 bit integer overflow. After it, it is properly
reported as:

	Lock   (0x1f) Signal= -58.64dBm C/N= 12.79dB

Fixes: 0f91c9d6bab9 ("[media] TS2020: Calculate tuner gain correctly")
Signed-off-by: Mauro Carvalho Chehab 
Signed-off-by: Greg Kroah-Hartman

[media] dvb-frontends: Drop owner assignment from i2c_driver

2015-08-11T15:58:20+00:00

i2c_driver does not need to set an owner because i2c_register_driver()
will set it.

Signed-off-by: Krzysztof Kozlowski 
Signed-off-by: Mauro Carvalho Chehab

ts2020: fix compilation on i386

2015-06-10T15:26:18+00:00

drivers/built-in.o: In function `ts2020_read_signal_strength':
ts2020.c:(.text+0x298ff94): undefined reference to `__divdi3'
ts2020.c:(.text+0x298ffd4): undefined reference to `__divdi3'
ts2020.c:(.text+0x298fffd): undefined reference to `__divdi3'
Makefile:921: recipe for target 'vmlinux' failed

Signed-off-by: Mauro Carvalho Chehab

[media] ts2020: Allow stats polling to be suppressed

2015-06-10T14:12:25+00:00

Statistics polling can not be done by lmedm04 driver's implementation of
M88RS2000/TS2020 because I2C messages stop the device's demuxer, so allow
polling for statistics to be suppressed in the ts2020 driver by setting
dont_poll in the ts2020_config struct.

Reported-by: Malcolm Priestley 
Signed-off-by: David Howells 
cc: Malcolm Priestley 
Signed-off-by: Antti Palosaari 
Signed-off-by: Mauro Carvalho Chehab

[media] ts2020: Copy loop_through from the config to the internal data

2015-06-10T14:11:38+00:00

Copy the loop_through setting from the ts2020_config struct to the internal
ts2020_priv struct so that it can actually be used.

Whilst we're at it, group the bitfields together in the same order in both
structs so that the compiler has a good chance to copy them in one go.

Signed-off-by: David Howells 
Signed-off-by: Antti Palosaari 
Signed-off-by: Mauro Carvalho Chehab

[media] ts2020: Provide DVBv5 API signal strength

2015-06-10T14:11:03+00:00

Provide a DVBv5 API signal strength.  This is in units of 0.001 dBm rather
than a percentage.

>From Antti Palosaari's testing with a signal generator, it appears that the
gain calculated according to Montage's specification if negated is a
reasonable representation of the signal strength of the generator.

To this end:

 (1) Polled statistic gathering needed to be implemented in the TS2020 driver.
     This is done in the ts2020_stat_work() function.

 (2) The calculated gain is placed as the signal strength in the
     dtv_property_cache associated with the front end with the scale set to
     FE_SCALE_DECIBEL.

 (3) The DVBv3 format signal strength then needed to be calculated from the
     signal strength stored in the dtv_property_cache rather than accessing
     the value when ts2020_read_signal_strength() is called.

Signed-off-by: David Howells 
Signed-off-by: Antti Palosaari 
Signed-off-by: Mauro Carvalho Chehab

[media] TS2020: Calculate tuner gain correctly

2015-06-10T14:10:27+00:00

The TS2020 and TS2022 tuners take an input from the demodulator indicating the
AGC setting on that component that is then used to influence the tuner's own
gain.  This should be taken into account when calculating the gain and signal
strength.

Further, the existing TS2020 driver miscalculates the signal strength as the
result of its calculations can exceed the storage capacity of the 16-bit word
used to return it to userspace.

To this end:

 (1) Add a callback function (->get_agc_pwm()) in the ts2020_config struct that
     the tuner can call to get the AGC PWM value from the demodulator.

 (2) Modify the TS2020 driver to calculate the gain according to Montage's
     specification with the adjustment that we produce a negative value and
     scale it to 0.001dB units (which is what the DVBv5 API will require):

     (a) Callback to the demodulator to retrieve the AGC PWM value and then
     	 turn that into Vagc for incorporation in the calculations.  If the
     	 callback is unset, assume a Vagc of 0.

     (b) Calculate the tuner gain from a combination of Vagc and the tuner's RF
     	 gain and baseband gain settings.

 (3) Turn this into a percentage signal strength as per Montage's
     specification for return to userspace with the DVBv3 API.

 (4) Provide a function in the M88DS3103 demodulator driver that can be used to
     get the AGC PWM value on behalf of the tuner.

 (5) The ts2020_config.get_agc_pwm function should be set by the code that
     stitches together the drivers for each card.

     For the DVBSky cards that use the M88DS3103 with the TS2020 or the TS2022,
     set the get_agc_pwm function to point to m88ds3103_get_agc_pwm.

I have tested this with a DVBSky S952 card which has an M88DS3103 and a TS2022.

Thanks to Montage for providing access to information about the workings of
these parts.

Signed-off-by: David Howells 
Signed-off-by: Antti Palosaari 
Signed-off-by: Mauro Carvalho Chehab

[media] ts2020: Add a comment about lifetime of on-stack pdata in ts2020_attach()

2015-06-10T14:00:06+00:00

ts2020_attach() allocates a variable pdata on the stack and then passes a
pointer to it to i2c_new_device() which stashes the pointer in persistent
structures.

Add a comment to the effect that this isn't actually an error because the
contents of the variable are only used in ts2020_probe() and this is only
called ts2020_attach()'s stack frame exists.

Signed-off-by: David Howells 
Signed-off-by: Antti Palosaari 
Signed-off-by: Mauro Carvalho Chehab

[media] ts2020: convert to regmap I2C API

2015-06-10T13:59:25+00:00

Use regmap to cover I2C register access.

Signed-off-by: Antti Palosaari 
Signed-off-by: Mauro Carvalho Chehab

[media] ts2020: register I2C driver from legacy media attach

2015-06-10T13:58:48+00:00

Register driver using I2C bindings internally when legacy media
attach is used. That is done by registering driver using I2C binding
from legacy attach. That way we can get valid I2C client, which is
needed for proper dev_() logging and regmap for example even legacy
binding is used.

Signed-off-by: Antti Palosaari 
Signed-off-by: Mauro Carvalho Chehab