Hi
On Sa, Jan 17, 2004 at 12:56:41 +1100, Benjamin Herrenschmidt wrote:
> On Sat, 2004-01-17 at 00:22, Alexander Clausen wrote:
> > On Fr, Jan 16, 2004 at 05:39:48 +1100, Benjamin Herrenschmidt wrote:
> > >
> > > It seem to be fairly easy to drive over i2c, somebody is already hacking
> > > something afaik.
> > >
> >
> > Yes, that somebody is me ;)
> > I've got the i2c read/write parts ready, it's only lacking automatic
> > detection of the i2c bus number (and eventually address?), I don't have
> > an idea how to do that exactly...
>
> sysfs ?
>
> Ben.
>
Attached is a patch to lmu.c to do automatic detection on Linux 2.6 via
sysfs. Please report if it works.
Alex
--- lmu.c.old 2004-01-18 16:38:35.000000000 +0100
+++ lmu.c 2004-01-21 17:17:14.358397224 +0100
@@ -37,45 +37,87 @@
/* #define DEBUG */
-#define ADDR 0x42
-
int
-open_bus ( ) {
- char filename[20], buf[4];
- int num = 0, file;
+probe_adapter (int *lmu_addr, int *device_num) {
+ int file;
+ int bytes;
+ char adapter[1024];
+ char filename[100];
+ __u32 raw_reg;
+ int lmu_bus;
+ int i;
+ int bus_num;
+
+ file = open ( "/proc/device-tree/uni-n/i2c/lmu-controller/reg",
O_RDONLY );
+ if ( file == -1 ) {
+ perror ("open failed");
+ printf ("no lmu device found\n");
+ return -1;
+ }
+
+ bytes = read ( file, &raw_reg, 4 );
+ if ( bytes == -1 ) {
+ perror ("read failed");
+ printf ("no lmu device found\n");
+ close ( file );
+ return -1;
+ }
- /* try eacch bus */
- while ( num <= 16 ) {
- snprintf( filename, 19, "/dev/i2c-%d", num );
+ close ( file );
+
+ lmu_bus = ( raw_reg & 0x000000001 );
+ *lmu_addr = ( raw_reg & 0xFE ) >> 1;
+
+ for (i = 0; i <= 16; i++) {
+ sprintf( filename, "/sys/class/i2c-adapter/i2c-%d/device/name",
i );
- if ( (file = open (filename, O_RDWR) ) < 0 ) {
- if ( errno == ENODEV ) {
- close ( file );
- return -1; /* last bus */
- } else if ( errno == EACCES ) {
- return -2; /* not root? */
- } else {
- num++; /* couldn't open file, try next bus */
- close ( file );
- continue;
- }
+ file = open( filename, O_RDONLY );
+ if ( file < 0 ) {
+ if (errno == ENOENT)
+ break;
}
- if ( ioctl ( file, I2C_SLAVE, ADDR) < 0 ) {
- num++; /* ioctl failed, try next bus */
+ bytes = read ( file, &adapter, 1023 );
+ adapter[bytes] = '\0';
+
+ if(bytes <= 0) {
+ perror("read() failed");
close ( file );
continue;
}
-
- if ( read ( file, buf, 4 ) == 4 ) {
- printf( "bus found: %s\n", filename );
- break; /* bus found */
- } {
- close ( file );
+ if ( sscanf ( adapter, "uni-n %d", &bus_num ) == 1 ) {
+ if ( bus_num == lmu_bus ) {
+ printf ( "lmu device found: /dev/i2c-%d\n", i );
+ *device_num = i;
+ close ( file );
+ return 1;
+ }
}
- num++;
+ close ( file );
+ }
+
+ return 0;
+}
+
+int
+open_bus ( ) {
+ char filename[20];
+ int num, addr, file, ret, err;
+
+ ret = probe_adapter (&addr, &num);
+
+ snprintf( filename, 19, "/dev/i2c-%d", num );
+
+ if ( (file = open (filename, O_RDWR) ) < 0 ) {
+ return errno;
+ }
+
+ if ( ioctl ( file, I2C_SLAVE, addr) < 0 ) {
+ err = errno;
+ close ( file );
+ return err;
}
return ( file != -1 ) ? file : -1;
--- lmu.h.old 2004-01-18 16:32:36.000000000 +0100
+++ lmu.h 2004-01-19 15:12:34.000000000 +0100
@@ -24,4 +24,6 @@
extern int get_env_light_level ( int dev, int *left, int *right );
+extern int probe_adapter ( int *addr, int *adapter );
+
#endif /* __LMU_H__ */
