On Thu, 30 Aug 2012 13:39:45 +0200, Jean Delvare wrote:
> Looking at the code in i2cdetect, it appears the checks are more strict
> than they need to be. Instead of bailing out by default if either quick
> writes or short reads aren't supported, we could simply warn and skip
> the addresses we can't probe. Only if both quick writes and short reads
> are unsupported, we should bail out. I can implement this easily if it
> solves your problem.
Like this:
If either SMBus Quick Write or SMBus Receive Byte command is missing,
still proceed and do a best-effort detection.
---
tools/i2cdetect.c | 56 ++++++++++++++++++++++++++++++++++++++---------------
1 file changed, 41 insertions(+), 15 deletions(-)
--- i2c-tools.orig/tools/i2cdetect.c 2012-04-26 12:05:55.000000000 +0200
+++ i2c-tools/tools/i2cdetect.c 2012-08-30 14:21:08.551693987 +0200
@@ -47,10 +47,11 @@ static void help(void)
" If provided, FIRST and LAST limit the probing range.\n");
}
-static int scan_i2c_bus(int file, int mode, int first, int last)
+static int scan_i2c_bus(int file, int mode, unsigned long funcs,
+ int first, int last)
{
int i, j;
- int res;
+ int cmd, res;
printf(" 0 1 2 3 4 5 6 7 8 9 a b c d e f\n");
@@ -59,8 +60,26 @@ static int scan_i2c_bus(int file, int mo
for(j = 0; j < 16; j++) {
fflush(stdout);
+ /* Select detection command for this address */
+ switch (mode) {
+ default:
+ cmd = mode;
+ break;
+ case MODE_AUTO:
+ if ((i+j >= 0x30 && i+j <= 0x37)
+ || (i+j >= 0x50 && i+j <= 0x5F))
+ cmd = MODE_READ;
+ else
+ cmd = MODE_QUICK;
+ break;
+ }
+
/* Skip unwanted addresses */
- if (i+j < first || i+j > last) {
+ if (i+j < first || i+j > last
+ || (cmd == MODE_READ &&
+ !(funcs & I2C_FUNC_SMBUS_READ_BYTE))
+ || (cmd == MODE_QUICK &&
+ !(funcs & I2C_FUNC_SMBUS_QUICK))) {
printf(" ");
continue;
}
@@ -79,8 +98,8 @@ static int scan_i2c_bus(int file, int mo
}
/* Probe this address */
- switch (mode) {
- case MODE_QUICK:
+ switch (cmd) {
+ default: /* MODE_QUICK */
/* This is known to corrupt the Atmel AT24RF08
EEPROM */
res = i2c_smbus_write_quick(file,
@@ -91,13 +110,6 @@ static int scan_i2c_bus(int file, int mo
write-only chips (mainly clock chips) */
res = i2c_smbus_read_byte(file);
break;
- default:
- if ((i+j >= 0x30 && i+j <= 0x37)
- || (i+j >= 0x50 && i+j <= 0x5F))
- res = i2c_smbus_read_byte(file);
- else
- res = i2c_smbus_write_quick(file,
- I2C_SMBUS_WRITE);
}
if (res < 0)
@@ -318,18 +330,32 @@ int main(int argc, char *argv[])
exit(0);
}
- if (mode != MODE_READ && !(funcs & I2C_FUNC_SMBUS_QUICK)) {
+ if (!(funcs & (I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_READ_BYTE))) {
+ fprintf(stderr,
+ "Error: Bus doesn't support detection commands\n");
+ close(file);
+ exit(1);
+ }
+ if (mode == MODE_QUICK && !(funcs & I2C_FUNC_SMBUS_QUICK)) {
fprintf(stderr, "Error: Can't use SMBus Quick Write command "
"on this bus\n");
close(file);
exit(1);
}
- if (mode != MODE_QUICK && !(funcs & I2C_FUNC_SMBUS_READ_BYTE)) {
+ if (mode == MODE_READ && !(funcs & I2C_FUNC_SMBUS_READ_BYTE)) {
fprintf(stderr, "Error: Can't use SMBus Read Byte command "
"on this bus\n");
close(file);
exit(1);
}
+ if (mode == MODE_AUTO) {
+ if (!(funcs & I2C_FUNC_SMBUS_QUICK))
+ fprintf(stderr, "Warning: Can't use SMBus Quick Write "
+ "command, will skip some addresses\n");
+ if (!(funcs & I2C_FUNC_SMBUS_READ_BYTE))
+ fprintf(stderr, "Warning: Can't use SMBus Read Byte "
+ "command, will skip some addresses\n");
+ }
if (!yes) {
char s[2];
@@ -352,7 +378,7 @@ int main(int argc, char *argv[])
}
}
- res = scan_i2c_bus(file, mode, first, last);
+ res = scan_i2c_bus(file, mode, funcs, first, last);
close(file);
--
Jean Delvare
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