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Date:      Thu, 19 Oct 2017 08:17:32 +0000 (UTC)
From:      Andriy Gapon <avg@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org
Subject:   svn commit: r324751 - stable/11/usr.sbin/i2c
Message-ID:  <201710190817.v9J8HWVf026728@repo.freebsd.org>
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Author: avg
Date: Thu Oct 19 08:17:32 2017
New Revision: 324751
URL: https://svnweb.freebsd.org/changeset/base/324751

Log:
  MFC r324590: i2c(8): clean up and clarify read operation

Modified:
  stable/11/usr.sbin/i2c/i2c.8
  stable/11/usr.sbin/i2c/i2c.c
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/usr.sbin/i2c/i2c.8
==============================================================================
--- stable/11/usr.sbin/i2c/i2c.8	Thu Oct 19 08:15:41 2017	(r324750)
+++ stable/11/usr.sbin/i2c/i2c.8	Thu Oct 19 08:17:32 2017	(r324751)
@@ -83,6 +83,10 @@ using selected addresses 'a:b:c'. This option is avail
 used.
 .It Fl o Ar offset
 offset within the device for data transfer (hex).
+The default is zero.
+Use
+.Dq -w 0
+to disable writing of the offset to the slave.
 .It Fl r
 reset the controller.
 .It Fl s
@@ -91,6 +95,12 @@ scan the bus for devices.
 be verbose.
 .It Fl w Ar 0|8|16
 device addressing width (in bits).
+This is used to determine how to pass
+.Ar offset
+specified with
+.Fl o
+to the slave.
+Zero means that the offset is ignored and not passed to the slave at all.
 .El
 .Sh WARNINGS
 Great care must be taken when manipulating slave I2C devices with the

Modified: stable/11/usr.sbin/i2c/i2c.c
==============================================================================
--- stable/11/usr.sbin/i2c/i2c.c	Thu Oct 19 08:15:41 2017	(r324750)
+++ stable/11/usr.sbin/i2c/i2c.c	Thu Oct 19 08:17:32 2017	(r324751)
@@ -212,15 +212,14 @@ start_over:
 				use_read_xfer = 1;
 				goto start_over;
 			}
-			cmd.slave = i << 1;
-			cmd.last = 1;
-			ioctl(fd, I2CSTOP, &cmd);
+			ioctl(fd, I2CSTOP);
 		}
 		if (error == 0) {
 			++num_found;
 			printf("%02x ", i);
 		}
 	}
+
 	/*
 	 * If we found nothing, maybe START is not supported and returns a
 	 * generic error code such as EIO or ENXIO, so try again using reads.
@@ -355,7 +354,7 @@ i2c_write(char *dev, struct options i2c_opt, char *i2c
 			}
 		}
 
-		error = ioctl(fd, I2CSTOP, &cmd);
+		error = ioctl(fd, I2CSTOP);
 		if (error == -1) {
 			err_msg = "ioctl: error sending stop condition";
 			goto err2;
@@ -439,8 +438,7 @@ i2c_write(char *dev, struct options i2c_opt, char *i2c
 		}
 		break;
 	}
-	cmd.slave = i2c_opt.addr;
-	error = ioctl(fd, I2CSTOP, &cmd);
+	error = ioctl(fd, I2CSTOP);
 	if (error == -1) {
 		err_msg = "ioctl: error sending stop condition";
 		goto err2;
@@ -450,8 +448,7 @@ i2c_write(char *dev, struct options i2c_opt, char *i2c
 	return (0);
 
 err1:
-	cmd.slave = i2c_opt.addr;
-	error = ioctl(fd, I2CSTOP, &cmd);
+	error = ioctl(fd, I2CSTOP);
 	if (error == -1)
 		fprintf(stderr, "error sending stop condition\n");
 err2:
@@ -466,7 +463,7 @@ static int
 i2c_read(char *dev, struct options i2c_opt, char *i2c_buf)
 {
 	struct iiccmd cmd;
-	int i, fd, error, bufsize;
+	int fd, error, bufsize;
 	char *err_msg, data = 0, *buf;
 
 	fd = open(dev, O_RDWR);
@@ -503,23 +500,22 @@ i2c_read(char *dev, struct options i2c_opt, char *i2c_
 		}
 
 		if (i2c_opt.mode == I2C_MODE_STOP_START) {
-			cmd.slave = i2c_opt.addr;
-			error = ioctl(fd, I2CSTOP, &cmd);
+			error = ioctl(fd, I2CSTOP);
 			if (error == -1) {
 				err_msg = "error sending stop condition";
 				goto err2;
 			}
 		}
 	}
-	cmd.slave = i2c_opt.addr;
+	cmd.slave = i2c_opt.addr | 1;
 	cmd.count = 1;
 	cmd.last = 0;
 	cmd.buf = &data;
-	if (i2c_opt.mode == I2C_MODE_STOP_START) {
+	if (i2c_opt.mode == I2C_MODE_STOP_START || i2c_opt.width == 0) {
 		error = ioctl(fd, I2CSTART, &cmd);
 		if (error == -1) {
 			err_msg = "ioctl: error sending start condition";
-			goto err1;
+			goto err2;
 		}
 	} else if (i2c_opt.mode == I2C_MODE_REPEATED_START) {
 		error = ioctl(fd, I2CRPTSTART, &cmd);
@@ -529,26 +525,27 @@ i2c_read(char *dev, struct options i2c_opt, char *i2c_
 			goto err1;
 		}
 	}
-	error = ioctl(fd, I2CSTOP, &cmd);
+
+	cmd.count = i2c_opt.count;
+	cmd.buf = i2c_buf;
+	cmd.last = 1;
+	error = ioctl(fd, I2CREAD, &cmd);
 	if (error == -1) {
-		err_msg = "error sending stop condition";
-		goto err2;
+		err_msg = "ioctl: error while reading";
+		goto err1;
 	}
 
-	for (i = 0; i < i2c_opt.count; i++) {
-		error = read(fd, &i2c_buf[i], 1);
-		if (error == -1) {
-			err_msg = "ioctl: error while reading";
-			goto err1;
-		}
+	error = ioctl(fd, I2CSTOP);
+	if (error == -1) {
+		err_msg = "error sending stop condtion\n";
+		goto err2;
 	}
 
 	close(fd);
 	return (0);
 
 err1:
-	cmd.slave = i2c_opt.addr;
-	error = ioctl(fd, I2CSTOP, &cmd);
+	error = ioctl(fd, I2CSTOP);
 	if (error == -1)
 		fprintf(stderr, "error sending stop condition\n");
 err2:

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