[linux-dvb] [PATCH] fix for CX24123 & low symbol rates

[Johannes Stezenbach]

Hi all,

On Mon, Feb 13, 2006, Vadim Catana wrote:
> This patch makes the following modifications to cx24123.c :
> 
> - fixed the reception of channels with low symbol rates.
>     ( The VGA1 and VGA2 offsets recommended by cx24109 docs for
>       symbol rates from 1 to 5 MSps do not work. I changed them
>       to values found experimentally. The charge pump current
>       and FILTUNE voltage are now set to values recommended in
>       the docs. This improves reception for symbol rates < 15 MSps.
>       The values written in the SYSSymbolRate registers are calculated
>       with better precision. )
> 
> - fixed the cx24123_get_fec() function. It was returning the values
>   for DCII mode.
> 
> - removed some unused variables
> 
> This patch includes the changes I sent earlier, that add support for
> diseqc.

does anyone here care to test this patch? (Even if you don't care about
the new features you'd still want to check for regressions).


Hi Vadim,

there are a few coding style issues, otherwise the patch looks good:

> +	u32 FILTUNE;

please avoid all-uppercase variable names, they look like macros

> +	/* choose the sampling rate high enough for the required operation,
> +	   while optimizing the power consumed by the demodulator */
> +	if(srate < (XTAL*2)/2) {
> +		pll_mult = 2;
> +	} else if(srate < (XTAL*3)/2) {
> +		pll_mult = 3;
> +	} else if(srate < (XTAL*4)/2) {
> +		pll_mult = 4;
> +	} else if(srate < (XTAL*5)/2) {
> +		pll_mult = 5;
> +	} else if(srate < (XTAL*6)/2) {
> +		pll_mult = 6;
> +	} else if(srate < (XTAL*7)/2) {
> +		pll_mult = 7;
> +	} else if(srate < (XTAL*8)/2) {
> +		pll_mult = 8;
> +	} else {
> +		pll_mult = 9;
> +	};

please add one space after "if", and no unnecessary { }


Thanks,
Johannes