Date: Tue, 15 Sep 2015 11:21:17 +0000 (UTC) From: Zbigniew Bodek <zbb@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r287820 - head/usr.sbin/i2c Message-ID: <201509151121.t8FBLH1w035646@repo.freebsd.org>
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Author: zbb Date: Tue Sep 15 11:21:16 2015 New Revision: 287820 URL: https://svnweb.freebsd.org/changeset/base/287820 Log: Perform I2C transmission in a single burst when mode is "none" or not set Some more automated I2C controllers cannot explicitly create START/STOP/etc. conditions on the bus. Instead, the correct condition is set automatically according to the pending transfer status. This particular behavior can cause trouble if some I2C slave requires sending address offset within the chip followed by the actual data or command. In that case we cannot assume that the driver will not STOP immediately after sending offset. To avoid that, do not split offset transfer from data transfer for default transmission modes and do exactly that if requested in command line (stop-start and repeated-start modes). This more generic approach should cover special cases like the one described. Reviewed by: imp Submitted by: Marcin Mazurek <mma@semihalf.com> Obtained from: Semihalf Modified: head/usr.sbin/i2c/i2c.c Modified: head/usr.sbin/i2c/i2c.c ============================================================================== --- head/usr.sbin/i2c/i2c.c Tue Sep 15 10:57:16 2015 (r287819) +++ head/usr.sbin/i2c/i2c.c Tue Sep 15 11:21:16 2015 (r287820) @@ -280,9 +280,6 @@ i2c_write(char *dev, struct options i2c_ err(1, "open failed"); } - /* - * Write offset where the data will go - */ cmd.slave = i2c_opt.addr; error = ioctl(fd, I2CSTART, &cmd); if (error == -1) { @@ -297,20 +294,24 @@ i2c_write(char *dev, struct options i2c_ err_msg = "error: offset malloc"; goto err1; } + } - cmd.count = bufsize; - cmd.buf = buf; - error = ioctl(fd, I2CWRITE, &cmd); - free(buf); - if (error == -1) { - err_msg = "ioctl: error when write offset"; - goto err1; + switch(i2c_opt.mode) { + case I2C_MODE_STOP_START: + /* + * Write offset where the data will go + */ + if (i2c_opt.width) { + cmd.count = bufsize; + cmd.buf = buf; + error = ioctl(fd, I2CWRITE, &cmd); + free(buf); + if (error == -1) { + err_msg = "ioctl: error when write offset"; + goto err1; + } } - } - /* Mode - stop start */ - if (i2c_opt.mode == I2C_MODE_STOP_START) { - cmd.slave = i2c_opt.addr; error = ioctl(fd, I2CSTOP, &cmd); if (error == -1) { err_msg = "ioctl: error sending stop condition"; @@ -322,9 +323,35 @@ i2c_write(char *dev, struct options i2c_ err_msg = "ioctl: error sending start condition"; goto err1; } - } - /* Mode - repeated start */ - if (i2c_opt.mode == I2C_MODE_REPEATED_START) { + + /* + * Write the data + */ + cmd.count = i2c_opt.count; + cmd.buf = i2c_buf; + cmd.last = 0; + error = ioctl(fd, I2CWRITE, &cmd); + if (error == -1) { + err_msg = "ioctl: error when write"; + goto err1; + } + break; + + case I2C_MODE_REPEATED_START: + /* + * Write offset where the data will go + */ + if (i2c_opt.width) { + cmd.count = bufsize; + cmd.buf = buf; + error = ioctl(fd, I2CWRITE, &cmd); + free(buf); + if (error == -1) { + err_msg = "ioctl: error when write offset"; + goto err1; + } + } + cmd.slave = i2c_opt.addr; error = ioctl(fd, I2CRPTSTART, &cmd); if (error == -1) { @@ -332,18 +359,42 @@ i2c_write(char *dev, struct options i2c_ "condition"; goto err1; } - } - /* - * Write the data - */ - cmd.count = i2c_opt.count; - cmd.buf = i2c_buf; - cmd.last = 0; - error = ioctl(fd, I2CWRITE, &cmd); - if (error == -1) { - err_msg = "ioctl: error when write"; - goto err1; + /* + * Write the data + */ + cmd.count = i2c_opt.count; + cmd.buf = i2c_buf; + cmd.last = 0; + error = ioctl(fd, I2CWRITE, &cmd); + if (error == -1) { + err_msg = "ioctl: error when write"; + goto err1; + } + break; + + case I2C_MODE_NONE: /* fall through */ + default: + buf = realloc(buf, bufsize + i2c_opt.count); + if (buf == NULL) { + err_msg = "error: data malloc"; + goto err1; + } + + memcpy(buf + bufsize, i2c_buf, i2c_opt.count); + /* + * Write offset and data + */ + cmd.count = bufsize + i2c_opt.count; + cmd.buf = buf; + cmd.last = 0; + error = ioctl(fd, I2CWRITE, &cmd); + free(buf); + if (error == -1) { + err_msg = "ioctl: error when write"; + goto err1; + } + break; } cmd.slave = i2c_opt.addr; error = ioctl(fd, I2CSTOP, &cmd);
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