Date: Mon, 3 Nov 1997 06:11:06 +0100 (MET) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: multimedia@freebsd.org Subject: A small addition to the bt848 driver... Message-ID: <199711030511.GAA17013@labinfo.iet.unipi.it>
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Hi,
yesterday I added a small piece of code to my version of the bt848
driver. It is an ioctl() which allows you to read/write peripherals
hanging off the I2C bus of the Bt84 -- such as the tuner, the
EEPROM, and the Teletext decoder.
While I wrote this because am working on a teletext decode, i think
this ioctl () will be useful to debug boards with new tuners etc. so I
suggest it to be added in the standard driver.
I have put the code within function tuner_ioctl()
static int
tuner_ioctl( bktr_ptr_t bktr, int unit, int cmd, caddr_t arg, struct
proc* pr )
{
...
case BT848_I2CWR: /* XXX */
{ u_long par = *(u_long *)arg;
u_char write = (par >> 24) & 0xff ;
int i2c_addr = (par >> 16) & 0xff ;
int i2c_port = (par >> 8) & 0xff ;
u_long data = (par) & 0xff ;
if (write) {
i2cWrite( bktr, i2c_addr, i2c_port, data);
} else {
data = i2cRead( bktr, i2c_addr);
}
*(u_long *)arg = (par & 0xffffff00) | ( data & 0xff );
}
break;
and the definition of BT848_I2CWR is in /sys/i386/include/ioctl_bt848.h
/*
* b7-b0: data (read/write)
* b15-b8: internal peripheral register (write)
* b23-b16: i2c addr (write)
* b31-b24: 1 = write, 0 = read
*/
#define BT848_I2CWR _IOWR('x', 57, u_long) /* i2c read-write */
Cheers
Luigi
-----------------------------+--------------------------------------
Luigi Rizzo | Dip. di Ingegneria dell'Informazione
email: luigi@iet.unipi.it | Universita' di Pisa
tel: +39-50-568533 | via Diotisalvi 2, 56126 PISA (Italy)
fax: +39-50-568522 | http://www.iet.unipi.it/~luigi/
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