i2ctransfer: new applet

i2ctransfer sends and receives user defined i2c messages

v2: apply Xabier's comments: add -a option, don't decrement argc,
    use bb_show_usage() and xzalloc()
v3: fix possible out of bound access to msgs[nmsgs]

Reviewed-by: Xabier Oneca -- xOneca <xoneca@gmail.com>
Signed-off-by: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/miscutils/i2c_tools.c b/miscutils/i2c_tools.c
index 610fed5d6b8568c03538f2c644d82f786d48050e..455ff028db870ae7c35720c1da387bf5dbd719fb 100644 (file)
--- a/miscutils/i2c_tools.c
+++ b/miscutils/i2c_tools.c
@@ -36,17 +36,26 @@
 //config:      help
 //config:      Detect I2C chips.
 //config:
+//config:config I2CTRANSFER
+//config:      bool "i2ctransfer (4.0 kb)"
+//config:      default y
+//config:      select PLATFORM_LINUX
+//config:      help
+//config:      Send user-defined I2C messages in one transfer.
+//config:
 
 //applet:IF_I2CGET(APPLET(i2cget, BB_DIR_USR_SBIN, BB_SUID_DROP))
 //applet:IF_I2CSET(APPLET(i2cset, BB_DIR_USR_SBIN, BB_SUID_DROP))
 //applet:IF_I2CDUMP(APPLET(i2cdump, BB_DIR_USR_SBIN, BB_SUID_DROP))
 //applet:IF_I2CDETECT(APPLET(i2cdetect, BB_DIR_USR_SBIN, BB_SUID_DROP))
+//applet:IF_I2CTRANSFER(APPLET(i2ctransfer, BB_DIR_USR_SBIN, BB_SUID_DROP))
 /* not NOEXEC: if hw operation stalls, use less memory in "hung" process */
 
 //kbuild:lib-$(CONFIG_I2CGET) += i2c_tools.o
 //kbuild:lib-$(CONFIG_I2CSET) += i2c_tools.o
 //kbuild:lib-$(CONFIG_I2CDUMP) += i2c_tools.o
 //kbuild:lib-$(CONFIG_I2CDETECT) += i2c_tools.o
+//kbuild:lib-$(CONFIG_I2CTRANSFER) += i2c_tools.o
 
 /*
  * Unsupported stuff:
@@ -80,12 +89,19 @@
 #define I2C_FUNCS                      0x0705
 #define I2C_PEC                                0x0708
 #define I2C_SMBUS                      0x0720
+#define I2C_RDWR                       0x0707
+#define I2C_RDWR_IOCTL_MAX_MSGS                42
+#define I2C_RDWR_IOCTL_MAX_MSGS_STR    "42"
 struct i2c_smbus_ioctl_data {
        __u8 read_write;
        __u8 command;
        __u32 size;
        union i2c_smbus_data *data;
 };
+struct i2c_rdwr_ioctl_data {
+       struct i2c_msg *msgs;   /* pointers to i2c_msgs */
+       __u32 nmsgs;            /* number of i2c_msgs */
+};
 /* end linux/i2c-dev.h */
 
 /*
@@ -262,7 +278,7 @@ static int i2c_bus_lookup(const char *bus_str)
        return xstrtou_range(bus_str, 10, 0, 0xfffff);
 }
 
-#if ENABLE_I2CGET || ENABLE_I2CSET || ENABLE_I2CDUMP
+#if ENABLE_I2CGET || ENABLE_I2CSET || ENABLE_I2CDUMP || ENABLE_I2CTRANSFER
 static int i2c_parse_bus_addr(const char *addr_str)
 {
        /* Slave address must be in range 0x03 - 0x77. */
@@ -1373,3 +1389,163 @@ int i2cdetect_main(int argc UNUSED_PARAM, char **argv)
        return 0;
 }
 #endif /* ENABLE_I2CDETECT */
+
+#if ENABLE_I2CTRANSFER
+static void check_i2c_func(int fd)
+{
+       unsigned long funcs;
+
+       get_funcs_matrix(fd, &funcs);
+
+       if (!(funcs & I2C_FUNC_I2C))
+               bb_error_msg_and_die("adapter does not support I2C transfers");
+}
+
+//usage:#define i2ctransfer_trivial_usage
+//usage:       "[-fay] I2CBUS {rLENGTH[@ADDR] | wLENGTH[@ADDR] DATA...}..."
+//usage:#define i2ctransfer_full_usage "\n\n"
+//usage:       "Read/write I2C data in one transfer"
+//usage:     "\n"
+//usage:     "\n       -f      Force access"
+//usage:     "\n       -a      Force scanning of non-regular addresses"
+//usage:     "\n       -y      Disable interactive mode"
+int i2ctransfer_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int i2ctransfer_main(int argc UNUSED_PARAM, char **argv)
+{
+       enum {
+               opt_f = (1 << 0),
+               opt_y = (1 << 1),
+               opt_a = (1 << 2),
+       };
+       int bus_num, bus_addr;
+       int fd;
+       unsigned opts, first, last;
+       int nmsgs, nmsgs_sent, i;
+       struct i2c_msg msgs[I2C_RDWR_IOCTL_MAX_MSGS];
+       struct i2c_rdwr_ioctl_data rdwr;
+
+       memset(msgs, 0, sizeof(msgs));
+
+       opts = getopt32(argv, "^"
+               "fya"
+               "\0" "-2" /* minimum 2 args */
+       );
+       first = 0x03;
+       last = 0x77;
+       if (opts & opt_a) {
+               first = 0x00;
+               last = 0x7f;
+       }
+
+       argv += optind;
+       bus_num = i2c_bus_lookup(argv[0]);
+       fd = i2c_dev_open(bus_num);
+       check_i2c_func(fd);
+
+       bus_addr = -1;
+       nmsgs = 0;
+       while (*++argv) {
+               char *arg_ptr;
+               unsigned len;
+               uint16_t flags;
+               char *end;
+
+               if (nmsgs >= I2C_RDWR_IOCTL_MAX_MSGS)
+                       bb_error_msg_and_die("too many messages, max: "I2C_RDWR_IOCTL_MAX_MSGS_STR);
+
+               flags = 0;
+               arg_ptr = *argv;
+               switch (*arg_ptr++) {
+               case 'r': flags |= I2C_M_RD; break;
+               case 'w': break;
+               default:
+                       bb_show_usage();
+               }
+
+               end = strchr(arg_ptr, '@');
+               if (end) *end = '\0';
+               len = xstrtou_range(arg_ptr, 0, 0, 0xffff);
+               if (end) {
+                       bus_addr = xstrtou_range(end + 1, 0, first, last);
+//TODO: will this work correctly if -f is specified?
+                       if (!(opts & opt_f))
+                               i2c_set_slave_addr(fd, bus_addr, (opts & opt_f));
+               } else {
+                       /* Reuse last address if possible */
+                       if (bus_addr < 0)
+                               bb_error_msg_and_die("no address given in '%s'", *argv);
+               }
+
+               msgs[nmsgs].addr = bus_addr;
+               msgs[nmsgs].flags = flags;
+               msgs[nmsgs].len = len;
+               if (len)
+                       msgs[nmsgs].buf = xzalloc(len);
+
+               if (!(flags & I2C_M_RD)) {
+                       /* Consume DATA arg(s) */
+                       unsigned buf_idx = 0;
+
+                       while (buf_idx < len) {
+                               uint8_t data8;
+                               unsigned long data;
+
+                               arg_ptr = *++argv;
+                               if (!arg_ptr)
+                                       bb_show_usage();
+                               data = strtoul(arg_ptr, &end, 0);
+                               if (data > 0xff || arg_ptr == end)
+                                       bb_error_msg_and_die("invalid data byte '%s'", *argv);
+
+                               data8 = data;
+                               while (buf_idx < len) {
+                                       msgs[nmsgs].buf[buf_idx++] = data8;
+                                       if (!*end)
+                                               break;
+                                       switch (*end) {
+                                       /* Pseudo randomness (8 bit AXR with a=13 and b=27) */
+                                       case 'p':
+                                               data8 = (data8 ^ 27) + 13;
+                                               data8 = (data8 << 1) | (data8 >> 7);
+                                               break;
+                                       case '+': data8++; break;
+                                       case '-': data8--; break;
+                                       case '=': break;
+                                       default:
+                                               bb_error_msg_and_die("invalid data byte suffix: '%s'",
+                                                                    *argv);
+                                       }
+                               }
+                       }
+               }
+               nmsgs++;
+       }
+
+       if (!(opts & opt_y))
+               confirm_action(bus_addr, 0, 0, 0);
+
+       rdwr.msgs = msgs;
+       rdwr.nmsgs = nmsgs;
+       nmsgs_sent = ioctl_or_perror_and_die(fd, I2C_RDWR, &rdwr, "I2C_RDWR");
+       if (nmsgs_sent < nmsgs)
+               bb_error_msg("warning: only %u/%u messages sent", nmsgs_sent, nmsgs);
+
+       for (i = 0; i < nmsgs_sent; i++) {
+               if (msgs[i].len != 0 && (msgs[i].flags & I2C_M_RD)) {
+                       int j;
+                       for (j = 0; j < msgs[i].len - 1; j++)
+                               printf("0x%02x ", msgs[i].buf[j]);
+                       /* Print final byte with newline */
+                       printf("0x%02x\n", msgs[i].buf[j]);
+               }
+       }
+
+# if ENABLE_FEATURE_CLEAN_UP
+       close(fd);
+       for (i = 0; i < nmsgs; i++)
+               free(msgs[i].buf);
+# endif
+
+       return 0;
+}
+#endif /* ENABLE_I2CTRANSFER */