Author: ian
Date: Sun Jun 23 15:55:41 2019
New Revision: 349310
URL: https://svnweb.freebsd.org/changeset/base/349310
Log:
MFC r348120:
Add a new 'tr' (transfer) mode to i2c(8) to support more i2c controllers.
Some i2c controller hardware does not provide a way to do individual START,
REPEAT-START and STOP actions on the i2c bus. Instead, they can only do
a complete transfer as a single operation. Typically they can do either
START-data-STOP or START-data-REPEATSTART-data-STOP. In the i2c driver
framework, this corresponds to the iicbus_transfer method. In the userland
interface they are initiated with the I2CRDWR ioctl command.
These changes add a new 'tr' mode which can be specified with the '-m'
command line option. This mode should work on all hardware; when an i2c
controller driver doesn't directly support the iicbus_transfer method,
code in the i2c driver framework uses the lower-level START/REPEAT/STOP
methods to implement the transfer. After this new mode has gotten some
testing on various hardware, the 'tr' mode should probably become the
new default mode.
PR: 189914
Modified:
stable/12/usr.sbin/i2c/i2c.8
stable/12/usr.sbin/i2c/i2c.c
Directory Properties:
stable/12/ (props changed)
Modified: stable/12/usr.sbin/i2c/i2c.8
==============================================================================
--- stable/12/usr.sbin/i2c/i2c.8 Sun Jun 23 15:09:39 2019
(r349309)
+++ stable/12/usr.sbin/i2c/i2c.8 Sun Jun 23 15:55:41 2019
(r349310)
@@ -25,7 +25,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd January 23, 2009
+.Dd May 22, 2019
.Dt I2C 8
.Os
.Sh NAME
@@ -39,7 +39,7 @@
.Op Fl w Ar 0|8|16
.Op Fl o Ar offset
.Op Fl c Ar count
-.Op Fl m Ar ss|rs|no
+.Op Fl m Ar tr|ss|rs|no
.Op Fl b
.Op Fl v
.Nm
@@ -72,10 +72,29 @@ number of bytes to transfer (dec).
transfer direction: r - read, w - write.
.It Fl f Ar device
I2C bus to use (default is /dev/iic0).
-.It Fl m Ar ss|rs|no
+.It Fl m Ar tr|ss|rs|no
addressing mode, i.e., I2C bus operations performed after the offset for the
transfer has been written to the device and before the actual read/write
-operation. rs - repeated start; ss - stop start; no - none.
+operation.
+.Bl -tag -compact -offset indent
+.It Va tr
+complete-transfer
+.It Va ss
+stop then start
+.It Va rs
+repeated start
+.It Va no
+none
+.El
+Some I2C bus hardware does not provide control over the individual start,
+repeat-start, and stop operations.
+Such hardware can only perform a complete transfer of the offset and the
+data as a single operation.
+The
+.Va tr
+mode creates control structures describing the transfer and submits them
+to the driver as a single complete transaction.
+This mode works on all types of I2C hardware.
.It Fl n Ar skip_addr
skip address - address(es) to be skipped during bus scan.
There are two ways to specify addresses to ignore: by range 'a..b' or
Modified: stable/12/usr.sbin/i2c/i2c.c
==============================================================================
--- stable/12/usr.sbin/i2c/i2c.c Sun Jun 23 15:09:39 2019
(r349309)
+++ stable/12/usr.sbin/i2c/i2c.c Sun Jun 23 15:55:41 2019
(r349310)
@@ -47,6 +47,7 @@ __FBSDID("$FreeBSD$");
#define I2C_MODE_NONE 1
#define I2C_MODE_STOP_START 2
#define I2C_MODE_REPEATED_START 3
+#define I2C_MODE_TRANSFER 4
struct options {
int width;
@@ -73,7 +74,7 @@ usage(void)
{
fprintf(stderr, "usage: %s -a addr [-f device] [-d [r|w]] [-o offset] "
- "[-w [0|8|16]] [-c count] [-m [ss|rs|no]] [-b] [-v]\n",
+ "[-w [0|8|16]] [-c count] [-m [tr|ss|rs|no]] [-b] [-v]\n",
getprogname());
fprintf(stderr, " %s -s [-f device] [-n skip_addr] -v\n",
getprogname());
@@ -297,24 +298,9 @@ static int
i2c_write(char *dev, struct options i2c_opt, char *i2c_buf)
{
struct iiccmd cmd;
- int ch, i, error, fd, bufsize;
+ int error, fd, bufsize;
char *err_msg, *buf;
- /*
- * Read data to be written to the chip from stdin
- */
- if (i2c_opt.verbose && !i2c_opt.binary)
- fprintf(stderr, "Enter %u bytes of data: ", i2c_opt.count);
-
- for (i = 0; i < i2c_opt.count; i++) {
- ch = getchar();
- if (ch == EOF) {
- free(i2c_buf);
- err(1, "not enough data, exiting\n");
- }
- i2c_buf[i] = ch;
- }
-
fd = open(dev, O_RDWR);
if (fd == -1) {
free(i2c_buf);
@@ -558,6 +544,72 @@ err2:
return (1);
}
+/*
+ * i2c_rdwr_transfer() - use I2CRDWR to conduct a complete i2c transfer.
+ *
+ * Some i2c hardware is unable to provide direct control over START, REPEAT-
+ * START, and STOP operations. Such hardware can only perform a complete
+ * START-<data>-STOP or START-<data>-REPEAT-START-<data>-STOP sequence as a
+ * single operation. The driver framework refers to this sequence as a
+ * "transfer" so we call it "transfer mode". We assemble either one or two
+ * iic_msg structures to describe the IO operations, and hand them off to the
+ * driver to be handled as a single transfer.
+ */
+static int
+i2c_rdwr_transfer(char *dev, struct options i2c_opt, char *i2c_buf)
+{
+ struct iic_msg msgs[2];
+ struct iic_rdwr_data xfer;
+ int fd, i;
+ union {
+ uint8_t buf[2];
+ uint8_t off8;
+ uint16_t off16;
+ } off;
+
+ i = 0;
+ if (i2c_opt.width > 0) {
+ msgs[i].flags = IIC_M_WR | IIC_M_NOSTOP;
+ msgs[i].slave = i2c_opt.addr;
+ msgs[i].buf = off.buf;
+ if (i2c_opt.width == 8) {
+ off.off8 = (uint8_t)i2c_opt.off;
+ msgs[i].len = 1;
+ } else {
+ off.off16 = (uint16_t)i2c_opt.off;
+ msgs[i].len = 2;
+ }
+ ++i;
+ }
+
+ /*
+ * If the transfer direction is write and we did a write of the offset
+ * above, then we need to elide the start; this transfer is just more
+ * writing that follows the one started above. For a read, we always do
+ * a start; if we did an offset write above it'll be a repeat-start
+ * because of the NOSTOP flag used above.
+ */
+ if (i2c_opt.dir == 'w')
+ msgs[i].flags = IIC_M_WR | (i > 0) ? IIC_M_NOSTART : 0;
+ else
+ msgs[i].flags = IIC_M_RD;
+ msgs[i].slave = i2c_opt.addr;
+ msgs[i].len = i2c_opt.count;
+ msgs[i].buf = i2c_buf;
+ ++i;
+
+ xfer.msgs = msgs;
+ xfer.nmsgs = i;
+
+ if ((fd = open(dev, O_RDWR)) == -1)
+ err(1, "open(%s) failed", dev);
+ if (ioctl(fd, I2CRDWR, &xfer) == -1 )
+ err(1, "ioctl(I2CRDWR) failed");
+ close(fd);
+
+ return (0);
+}
+
int
main(int argc, char** argv)
{
@@ -620,6 +672,8 @@ main(int argc, char** argv)
i2c_opt.mode = I2C_MODE_STOP_START;
else if (!strcmp(optarg, "rs"))
i2c_opt.mode = I2C_MODE_REPEATED_START;
+ else if (!strcmp(optarg, "tr"))
+ i2c_opt.mode = I2C_MODE_TRANSFER;
else
usage();
break;
@@ -687,19 +741,33 @@ main(int argc, char** argv)
if (i2c_buf == NULL)
err(1, "data malloc");
+ /*
+ * For a write, read the data to be written to the chip from stdin.
+ */
if (i2c_opt.dir == 'w') {
- error = i2c_write(dev, i2c_opt, i2c_buf);
- if (error) {
- free(i2c_buf);
- return (1);
+ if (i2c_opt.verbose && !i2c_opt.binary)
+ fprintf(stderr, "Enter %u bytes of data: ",
+ i2c_opt.count);
+ for (i = 0; i < i2c_opt.count; i++) {
+ ch = getchar();
+ if (ch == EOF) {
+ free(i2c_buf);
+ err(1, "not enough data, exiting\n");
+ }
+ i2c_buf[i] = ch;
}
}
- if (i2c_opt.dir == 'r') {
+
+ if (i2c_opt.mode == I2C_MODE_TRANSFER)
+ error = i2c_rdwr_transfer(dev, i2c_opt, i2c_buf);
+ else if (i2c_opt.dir == 'w')
+ error = i2c_write(dev, i2c_opt, i2c_buf);
+ else
error = i2c_read(dev, i2c_opt, i2c_buf);
- if (error) {
- free(i2c_buf);
- return (1);
- }
+
+ if (error != 0) {
+ free(i2c_buf);
+ return (1);
}
if (i2c_opt.verbose)
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