[linux-dvb] Re: MT352 i2c register writing patch

[Holger Waechtler <holger@qanu.de>]

Hi Patrick,

oops, sorry -- I misunderstood the problem, forget my other mail. Your 
patch looks ok.
sorry again,

Holger



Patrick Boettcher wrote:

> Hi again,
>
> I'm adding support for a new USB2.0 device to the dibusb-driver 
> (HanfTek UMT 010).
>
> This device is currently equipped with a MT352 demodulator, thanks to 
> OpenSource and the help of volunteers, this frontend is already 
> supported :).
>
> This device uses a similar protocol to control itself as all the other 
> dibusb-devices. The problem is, that the dibusb-protocol doesn't allow 
> to write to more than one i2c-register within one i2c-write-process, 
> but the mt352 is doing exactly that.
>
> I think to put the splitting of connected mt352-writes into the dibusb 
> driver is the wrong place. IMHO it would be better to change the 
> i2c_write of the mt352. The attached patch does this, for me with 
> success. I don't know if raising the number of i2c-writes would 
> produce any problems with e.g. the airstar2 cards.
>
> If no one is going to protest, I will commit this change along with 
> the dibusb changes when I the device is working.
>
> regards,
> Patrick.
>
> --
>   Mail: patrick.boettcher@desy.de
>   WWW:  http://www.wi-bw.tfh-wildau.de/~pboettch/
>
> ------------------------------------------------------------------------
>
> Index: mt352.c
> ===================================================================
> RCS file: /cvs/linuxtv/dvb-kernel/linux/drivers/media/dvb/frontends/mt352.c,v
> retrieving revision 1.20
> diff -u -3 -p -r1.20 mt352.c
> --- mt352.c	19 Nov 2004 01:11:42 -0000	1.20
> +++ mt352.c	5 Jan 2005 12:20:29 -0000
> @@ -58,17 +58,27 @@ static int debug;
> 		if (debug) printk(KERN_DEBUG "mt352: " args); \
> 	} while (0)
>
> -int mt352_write(struct dvb_frontend* fe, u8* ibuf, int ilen)
> +static int mt352_single_write(struct dvb_frontend *fe, u8 reg, u8 val)
> {
> 	struct mt352_state* state = (struct mt352_state*) fe->demodulator_priv;
> +	u8 buf[2] = { reg, val };
> 	struct i2c_msg msg = { .addr = state->config->demod_address, .flags = 0,
> -			       .buf = ibuf, .len = ilen };
> +			       .buf = buf, .len = 2 };
> 	int err = i2c_transfer(state->i2c, &msg, 1);
> 	if (err != 1) {
> -		dprintk("mt352_write() failed (err = %d)!\n", err);
> +		dprintk("mt352_write() to reg %x failed (err = %d)!\n", reg, err);
> 		return err;
> 	}
> +	return 0; 
> +}
>
> +int mt352_write(struct dvb_frontend* fe, u8* ibuf, int ilen)
> +{
> +	int err,i;
> +	for (i=0; i < ilen-1; i++)
> +		if ((err = mt352_single_write(fe,ibuf[0]+i,ibuf[i+1]))) 
> +			return err;
> +	
> 	return 0;
> }
>
>