Tested on a Raspberry Pi 400 with a BME680 connected to the relevant
pins, and commands like `i2ctransfer 1 w3@0x77 0x60 0xb6 0xd0 r1`, which
writes 0xb6 to register 0x60 of chip 0x77 on bus 1, and then reads one
byte.
---
toys/other/i2ctools.c | 101 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 101 insertions(+)
From 815076b3b4147c77c1d5b04defd50d298d21456c Mon Sep 17 00:00:00 2001
From: Elliott Hughes <e...@google.com>
Date: Thu, 6 Jul 2023 16:19:26 -0700
Subject: [PATCH] Add i2ctransfer.
Tested on a Raspberry Pi 400 with a BME680 connected to the relevant
pins, and commands like `i2ctransfer 1 w3@0x77 0x60 0xb6 0xd0 r1`, which
writes 0xb6 to register 0x60 of chip 0x77 on bus 1, and then reads one
byte.
---
toys/other/i2ctools.c | 101 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 101 insertions(+)
diff --git a/toys/other/i2ctools.c b/toys/other/i2ctools.c
index ad296adf..95280988 100644
--- a/toys/other/i2ctools.c
+++ b/toys/other/i2ctools.c
@@ -17,6 +17,7 @@ USE_I2CDETECT(NEWTOY(i2cdetect, ">3aFlqry[!qr]", TOYFLAG_USR|TOYFLAG_SBIN))
USE_I2CDUMP(NEWTOY(i2cdump, "<2>2fy", TOYFLAG_USR|TOYFLAG_SBIN))
USE_I2CGET(NEWTOY(i2cget, "<2>3fy", TOYFLAG_USR|TOYFLAG_SBIN))
USE_I2CSET(NEWTOY(i2cset, "<4fy", TOYFLAG_USR|TOYFLAG_SBIN))
+USE_I2CTRANSFER(NEWTOY(i2ctransfer, "<2vfy", TOYFLAG_USR|TOYFLAG_SBIN))
config I2CDETECT
bool "i2cdetect"
@@ -67,6 +68,22 @@ config I2CSET
-f Force access to busy devices
-y Skip confirmation prompts (yes to all)
+
+config I2CTRANSFER
+ bool "i2ctransfer"
+ default y
+ help
+ usage: i2ctransfer [-fy] BUS DESC [DATA...]...
+
+ Make i2c transfers. DESC is 'r' for read or 'w' for write, followed by
+ the number of bytes to read or write, followed by '@' and a 7-bit address.
+ For any message after the first, the '@' and address can be omitted to
+ reuse the previous address. A 'w' DESC must be followed by the number of
+ DATA bytes that was specified in the DESC.
+
+ -f Force access to busy devices
+ -v Verbose (show messages sent, not just received)
+ -y Skip confirmation prompts (yes to all)
*/
#define FOR_i2cdetect
@@ -313,3 +330,87 @@ void i2cset_main(void)
xioctl(fd, I2C_SMBUS, &ioctl_data);
close(fd);
}
+
+#define FOR_i2ctransfer
+#include "generated/flags.h"
+
+static void show_msgs(FILE *fp, struct i2c_rdwr_ioctl_data *data, int before)
+{
+ int i;
+
+ for (i = 0; i < data->nmsgs; i++) {
+ struct i2c_msg *msg = &data->msgs[i];
+ int j, write = !msg->flags, hexdump;
+
+ // Even with -v we can't show read data before it's read!
+ hexdump = (before && write) || (!before && !write) || (!before && FLAG(v));
+ if (!before && !FLAG(v) && !hexdump) continue;
+
+ if (before || FLAG(v)) {
+ fprintf(fp, "msg %d: addr 0x%02x, %s, length %u%s", i, msg->addr,
+ write ? "write" : "read", msg->len, hexdump ? ", data " : "");
+ }
+ if (hexdump) {
+ for (j = 0; j < msg->len; j++) fprintf(fp, "0x%02x ", msg->buf[j]);
+ }
+ fprintf(fp, "\n");
+ }
+}
+
+void i2ctransfer_main(void)
+{
+ int fd, bus = atolx_range(toys.optargs[0], 0, 0x3f), i = 1, j;
+ char *arg, *addr_str;
+ struct i2c_rdwr_ioctl_data ioctl_data;
+ struct i2c_msg msgs[I2C_RDWR_IOCTL_MAX_MSGS], *msg;
+
+ ioctl_data.msgs = msgs;
+ ioctl_data.nmsgs = 0;
+
+ while ((arg = toys.optargs[i++])) {
+ if (ioctl_data.nmsgs >= I2C_RDWR_IOCTL_MAX_MSGS) error_exit("too much!");
+
+ msg = &msgs[ioctl_data.nmsgs];
+ if (*arg == 'r') {
+ msg->flags = I2C_M_RD;
+ } else if (*arg == 'w') {
+ msg->flags = 0;
+ } else error_exit("expected read or write: %s", arg);
+
+ addr_str = strchr(arg, '@');
+ if (addr_str) {
+ msg->addr = atolx_range(addr_str + 1, 0, 0x7f);
+ *addr_str = '\0';
+ } else {
+ if (ioctl_data.nmsgs == 0) error_exit("missing address: %s", arg);
+ msg->addr = msgs[ioctl_data.nmsgs - 1].addr;
+ }
+
+ // The struct field is 16 bits, but the kernel (as of 6.4) limits each
+ // message to 8KiB. Either is far larger than you're likely to see in
+ // practice.
+ msg->len = atolx_range(arg + 1, 0, 0xffff);
+ msg->buf = xzalloc(msg->len);
+ if (*arg == 'w') {
+ for (j = 0; j < msg->len; j++) {
+ arg = toys.optargs[i++];
+ if (!arg) error_exit("expected %d data bytes", msg->len);
+ msg->buf[j] = atolx_range(arg, 0, 0xff);
+ }
+ }
+
+ ioctl_data.nmsgs++;
+ }
+
+ fprintf(stderr, "Will send following messages on bus %d...\n", bus);
+ show_msgs(stderr, &ioctl_data, 1);
+ confirm("Send transfers on bus %d?", bus);
+
+ fd = i2c_open(bus, 0, 0);
+ xioctl(fd, I2C_RDWR, &ioctl_data);
+ close(fd);
+
+ show_msgs(stdout, &ioctl_data, 0);
+
+ for (i = 0; i < ioctl_data.nmsgs; i++) free(msgs[i].buf);
+}
--
2.41.0.255.g8b1d071c50-goog
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