On 10/31/2014 04:34 AM, Nibble Max wrote:
Hello Antti,
On 2014-10-31 01:36:14, Antti Palosaari wrote:
On 10/30/2014 06:38 AM, Nibble Max wrote:
- if (tab_len > 83) {
+ if (tab_len > 86) {
That is not nice, but I could try find better solution and fix it later.
What is the reason to check this parameter?
How about remove this check?
It is just to check you will not overwrite buffer accidentally. Buffer
is 83 bytes long, which should be also increased...
The correct solution is somehow calculate max possible tab size on
compile time. It should be possible as init tabs are static const
tables. Use some macro to calculate max value and use it - not plain
numbers.
Something like that
#define BUF_SIZE MAX(m88ds3103_tab_dvbs, m88ds3103_tab_dvbs2,
m88rs6000_tab_dvbs, m88rs6000_tab_dvbs2)
Clock selection. What this does:
* select mclk_khz
* select target_mclk
* calls set_config() in order to pass target_mclk to tuner driver
* + some strange looking sleep, which is not likely needed
The clock of M88RS6000's demod comes from tuner dies.
So the first thing is turning on the demod main clock from tuner die after the
demod reset.
Without this clock, the following register's content will fail to update.
Before changing the demod main clock, it should close clock path.
After changing the demod main clock, it open clock path and wait the clock to
stable.
One thing what I don't like this is that you have implemented M88RS6000
things here and M88DS3103 elsewhere. Generally speaking, code must have
some logic where same things are done in same place. So I expect to see
both M88DS3103 and M88RS6000 target_mclk and mclk_khz selection
implemented here or these moved to place where M88DS3103 implementation is.
I will move M88DS3103 implementation to here.
Also, even set_config() is somehow logically correctly used here, I
prefer to duplicate that 4 line long target_mclk selection to tuner
driver and get rid of whole set_config(). Even better solution could be
to register M88RS6000 as a clock provider using clock framework, but
imho it is not worth that simple case.
Do you suggest to set demod main clock and ts clock in tuner's set_params call
back?
Yes, and you did it already on that latest patch, thanks. It is not
logically correct, but a bit hackish solution, but I think it is best in
that special case in order to keep things simple here.
One thing with that new patch I would like to check is this 10us delay
after clock path is enabled. You enable clock just before mcu is stopped
and demod is configured during mcu is on freeze. 10us is almost nothing
and it sounds like having no need in a situation you stop even mcu. It
is about one I2C command which will took longer than 10us. Hard to see
why you need wait 10us to settle clock in such case. What happens if you
don't wait? I assume nothing, it works just as it should as stable
clocks are needed a long after that, when mcu is take out of reset.
usleep_range(10000, 20000);
This delay time at least is 10ms, not 10us.
ah, yes, you were correct. 10ms is indeed a much larger, it is about
century on a digital logic signal path where frequency is around 100MHz.
100MHz clock means clock cycle is 10ns, 10ms is 10000000ns => 1,000,000
- one million clock cycles. Whilst I don't know how chip designed in a
logic level, I have still done some digital logic designing myself and
this sounds long.
If you don't enable clock path, what is next command which will fail?
Probably it will not even fail, but never lock to signal as demod core
is not clocked at all.
regards
Antti
--
http://palosaari.fi/
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