Changeset 5237

Timestamp:

05/05/08 14:38:22 (4 years ago)

Author:

khali

Message:

Add support for short writes (SMBus send byte).

Location:

i2c-tools/trunk

Files:

• CHANGES (modified) (1 diff)
• tools/i2cset.8 (modified) (2 diffs)
• tools/i2cset.c (modified) (9 diffs)

i2c-tools/trunk/CHANGES

@@ -15 +15 @@
           Restrict the chip address to 0x03-0x77
           Split the code into several functions for clarity
+          Add support for short writes (SMBus send byte)
 
 3.0.1 (2008-04-04)

i2c-tools/trunk/tools/i2cset.8

@@ -10 +10 @@
 .I chip-address
 .I data-address
-.I value
-.RI [ "mode " [ mask ]]
+.RI [ "value " [ "mode " [ mask ]]]
 .br
 .B i2cset
@@ -39 +38 @@
 scripts.
 .PP
-There are four required options to i2cset. \fIi2cbus\fR indicates the number
+There are three required options to i2cset. \fIi2cbus\fR indicates the number
 or name of the I2C bus to be scanned.  This number should correspond to one of
 the busses listed by \fIi2cdetect -l\fR. \fIchip-address\fR specifies the
 address of the chip on that bus, and is an integer between 0x03 and 0x77.
 \fIdata-address\fR specifies the address on that chip to write to, and is an
-integer between 0x00 and 0xFF. \fIvalue\fR is the value to write to that
-location on the chip.
+integer between 0x00 and 0xFF.
+.PP
+The \fIvalue\fR parameter, if specified, is the value to write to that
+location on the chip. If this parameter is omited, then a short write is
+issued. For most chips, it simply sets an internal pointer to the target
+location, but doesn't actually write to that location. For a few chips
+though, in particular simple ones with a single register, this short write
+is an actual write.
 .PP
 The \fImode\fR parameter, if specified, is one of the letters \fBb\fP or

i2c-tools/trunk/tools/i2cset.c

@@ -36 +36 @@
 {
         fprintf(stderr,
-                "Usage: i2cset [-f] [-y] I2CBUS CHIP-ADDRESS DATA-ADDRESS VALUE [MODE [MASK]]\n"
+                "Usage: i2cset [-f] [-y] I2CBUS CHIP-ADDRESS DATA-ADDRESS [VALUE [MODE [MASK]]]\n"
                 "  I2CBUS is an integer or an I2C bus name\n"
                 "  ADDRESS is an integer (0x03 - 0x77)\n"
@@ -58 +58 @@
 
         switch (size) {
+        case I2C_SMBUS_BYTE:
+                if (!(funcs & I2C_FUNC_SMBUS_WRITE_BYTE)) {
+                        fprintf(stderr, "Error: Adapter for i2c bus %d does "
+                                "not have byte send capability\n", i2cbus);
+                        return -1;
+                }
+                break;
+
         case I2C_SMBUS_BYTE_DATA:
                 if (!(funcs & I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
@@ -101 +109 @@
 
         fprintf(stderr, "I will write to device file %s, chip address "
-                "0x%02x, data address\n0x%02x, data 0x%02x%s, mode "
-                "%s.\n", filename, address, daddress, value,
-                vmask ? " (masked)" : "",
-                size == I2C_SMBUS_BYTE_DATA ? "byte" : "word");
+                "0x%02x, data address\n0x%02x, ", filename, address, daddress);
+        if (size == I2C_SMBUS_BYTE)
+                fprintf(stderr, "no data.\n");
+        else
+                fprintf(stderr, "data 0x%02x%s, mode %s.\n", value,
+                        vmask ? " (masked)" : "",
+                        size == I2C_SMBUS_BYTE_DATA ? "byte" : "word");
         if (pec)
                 fprintf(stderr, "PEC checking enabled.\n");
@@ -148 +159 @@
         }
 
-        if (argc < flags + 5)
+        if (argc < flags + 4)
                 help();
 
@@ -165 +176 @@
         }
 
-        value = strtol(argv[flags+4], &end, 0);
-        if (*end) {
-                fprintf(stderr, "Error: Data value invalid!\n");
-                help();
+        if (argc > flags + 4) {
+                size = I2C_SMBUS_BYTE_DATA;
+                value = strtol(argv[flags+4], &end, 0);
+                if (*end || value < 0) {
+                        fprintf(stderr, "Error: Data value invalid!\n");
+                        help();
+                }
+        } else {
+                size = I2C_SMBUS_BYTE;
+                value = -1;
         }
 
@@ -180 +197 @@
                 }
                 pec = argv[flags+5][1] == 'p';
-        } else {
-                size = I2C_SMBUS_BYTE_DATA;
         }
 
@@ -192 +207 @@
         }
 
-        if (value < 0
-         || (size == I2C_SMBUS_BYTE_DATA && value > 0xff)
+        if ((size == I2C_SMBUS_BYTE_DATA && value > 0xff)
          || (size == I2C_SMBUS_WORD_DATA && value > 0xffff)) {
                 fprintf(stderr, "Error: Data value out of range!\n");
@@ -250 +264 @@
         }
 
-        if (size == I2C_SMBUS_WORD_DATA) {
+        switch (size) {
+        case I2C_SMBUS_BYTE:
+                res = i2c_smbus_write_byte(file, daddress);
+                break;
+        case I2C_SMBUS_WORD_DATA:
                 res = i2c_smbus_write_word_data(file, daddress, value);
-        } else {
+                break;
+        default: /* I2C_SMBUS_BYTE_DATA */
                 res = i2c_smbus_write_byte_data(file, daddress, value);
         }
@@ -270 +289 @@
         }
 
-        if (size == I2C_SMBUS_WORD_DATA) {
+        switch (size) {
+        case I2C_SMBUS_BYTE:
+                /* No readback */
+                break;
+        case I2C_SMBUS_WORD_DATA:
                 res = i2c_smbus_read_word_data(file, daddress);
-        } else {
+                break;
+        default: /* I2C_SMBUS_BYTE_DATA */
                 res = i2c_smbus_read_byte_data(file, daddress);
         }
         close(file);
+
+        if (size == I2C_SMBUS_BYTE) /* We're done */
+                exit(0);
 
         if (res < 0) {