This version implements i2cdump. The only program left before the real patch
is i2cdetect.

Signed-off-by: Bartosz Golaszewski <[email protected]>
---
 miscutils/i2c_tools.c | 1052 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 1052 insertions(+)
 create mode 100644 miscutils/i2c_tools.c

diff --git a/miscutils/i2c_tools.c b/miscutils/i2c_tools.c
new file mode 100644
index 0000000..1dbb29c
--- /dev/null
+++ b/miscutils/i2c_tools.c
@@ -0,0 +1,1052 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Minimal i2c-tools implementation for busybox.
+ * Parts of code ported from i2c-tools:
+ *             http://www.lm-sensors.org/wiki/I2CTools.
+ *
+ * Copyright (C) 2014 by Bartosz Golaszewski <[email protected]>
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ */
+
+//config:config I2CGET
+//config:      bool "i2cget"
+//config:      default y
+//config:      select PLATFORM_LINUX
+//config:      help
+//config:        Read from I2C/SMBus chip registers.
+//config:
+//config:config I2CSET
+//config:      bool "i2cset"
+//config:      default y
+//config:      select PLATFORM_LINUX
+//config:      help
+//config:        Set I2C registers.
+//config:
+//config:config I2CDUMP
+//config:      bool "i2cdump"
+//config:      default y
+//config:      select PLATFORM_LINUX
+//config:      help
+//config:        Examine I2C registers.
+//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))
+
+//kbuild:lib-$(CONFIG_I2CGET) += i2c_tools.o
+//kbuild:lib-$(CONFIG_I2CSET) += i2c_tools.o
+//kbuild:lib-$(CONFIG_I2CDUMP) += i2c_tools.o
+
+//usage:#define i2cget_trivial_usage
+//usage:       "[-f] [-y] BUS CHIP-ADDRESS [DATA-ADDRESS [MODE]]"
+//usage:#define i2cget_full_usage "\n\n"
+//usage:       "Read from I2C/SMBus chip registers\n"
+//usage:     "\n  I2CBUS is an i2c bus number"
+//usage:     "\n  ADDRESS is an integer (0x03 - 0x77)"
+//usage:     "\n  MODE is one of:"
+//usage:     "\n    b (read byte data, default)"
+//usage:     "\n    w (read word data)"
+//usage:     "\n    c (write byte/read byte)"
+//usage:   "\n\n  Append p for SMBus PEC"
+//usage:   "\n\n  -f - force access to device"
+//usage:     "\n  -y - disable interactive mode"
+//usage:
+//usage:#define i2cset_trivial_usage
+//usage:       "[-f] [-y] [-m MASK] BUS CHIP-ADDR DATA-ADDR [VALUE] ... [MODE]"
+//usage:#define i2cset_full_usage "\n\n"
+//usage:       "Set I2C registers\n"
+//usage:     "\n  I2CBUS is an i2c bus number"
+//usage:     "\n  ADDRESS is an integer (0x03 - 0x77)"
+//usage:     "\n  MODE is one of:"
+//usage:     "\n    c (byte, no value)"
+//usage:     "\n    b (byte data, default)"
+//usage:     "\n    w (word data)"
+//usage:     "\n    i (I2C block data)"
+//usage:     "\n    s (SMBus block data)"
+//usage:   "\n\n  Append p for SMBus PEC"
+//usage:   "\n\n  -f - force access to device"
+//usage:     "\n  -y - disable interactive mode"
+//usage:     "\n  -r - read back and compare the result"
+//usage:     "\n  -m - mask specifying which bits to write"
+//usage:
+//usage:#define i2cdump_trivial_usage
+//usage:       "[-f] [-r FIRST-LAST] [-y] BUS ADDR [MODE]"
+//usage:#define i2cdump_full_usage "\n\n"
+//usage:       "Examine I2C registers\n"
+//usage:     "\n  I2CBUS is an i2c bus number"
+//usage:     "\n  ADDRESS is an integer (0x03 - 0x77)"
+//usage:     "\n  MODE is one of:"
+//usage:     "\n    b (byte, default)"
+//usage:     "\n    w (word)"
+//usage:     "\n    W (word on even register addresses)"
+//usage:     "\n    i (I2C block)"
+//usage:     "\n    s (SMBus block)"
+//usage:     "\n    c (consecutive byte)"
+//usage:   "\n\n  Append p for SMBus PEC"
+//usage:   "\n\n  -f - force access to device"
+//usage:     "\n  -y - disable interactive mode"
+//usage:     "\n  -r - limit the number of registers being accessed"
+//usage:
+
+/*
+ * Unsupported stuff:
+ *
+ * - upstream i2c-tools can also look-up i2c busses by name, we only accept
+ *   numbers,
+ * - bank and bankreg parameters for i2cdump are not supported because of
+ *   their limited usefulness (see i2cdump manual entry for more info),
+ *   although this is a potential TODO.
+ */
+
+#include "libbb.h"
+
+/*
+ * /dev/i2c-X ioctl commands. The ioctl's parameter is always an unsigned long,
+ * except for:
+ *    - I2C_FUNCS, takes pointer to an unsigned long
+ *    - I2C_RDWR, takes pointer to struct i2c_rdwr_ioctl_data
+ *    - I2C_SMBUS, takes pointer to struct i2c_smbus_ioctl_data
+ */
+
+/* Number of times a device address should be polled when not acknowledging */
+#define I2C_RETRIES    0x0701
+/* Set timeout in units of 10 ms */
+#define I2C_TIMEOUT    0x0702
+
+/*
+ * NOTE: Slave address is 7 or 10 bits, but 10-bit addresses
+ * are NOT supported! (due to code brokenness)
+ */
+
+/* Use this slave address */
+#define I2C_SLAVE      0x0703
+/* Use this slave address, even if it is already in use by a driver! */
+#define I2C_SLAVE_FORCE        0x0706
+/* 0 for 7 bit addrs, != 0 for 10 bit */
+#define I2C_TENBIT     0x0704
+/* Get the adapter functionality mask */
+#define I2C_FUNCS      0x0705
+/* Combined R/W transfer (one STOP only) */
+#define I2C_RDWR       0x0707
+/* != 0 to use PEC with SMBus */
+#define I2C_PEC                0x0708
+/* SMBus transfer */
+#define I2C_SMBUS      0x0720
+
+/* This is the structure as used in the I2C_SMBUS ioctl call */
+struct i2c_smbus_ioctl_data {
+       uint8_t read_write;
+       uint8_t command;
+       uint32_t size;
+       union i2c_smbus_data *data;
+};
+
+/* This is the structure as used in the I2C_RDWR ioctl call */
+struct i2c_rdwr_ioctl_data {
+       struct i2c_msg *msgs;   /* pointers to i2c_msgs */
+       uint32_t nmsgs;                 /* number of i2c_msgs */
+};
+
+/* As specified in SMBus standard */
+#define I2C_SMBUS_BLOCK_MAX            32
+/* Not specified but we use same structure */
+#define I2C_SMBUS_I2C_BLOCK_MAX                32
+
+/*
+ * Data for SMBus Messages
+ */
+union i2c_smbus_data {
+       uint8_t byte;
+       uint16_t word;
+       /* block[0] is used for length and one more for PEC */
+       uint8_t block[I2C_SMBUS_BLOCK_MAX + 2];
+};
+
+#define  I2C_RDRW_IOCTL_MAX_MSGS       42
+
+#define I2C_MAX_REGS                   256
+
+/* smbus_access read or write markers */
+#define I2C_SMBUS_READ 1
+#define I2C_SMBUS_WRITE        0
+
+/* SMBus transaction types (size parameter in the below functions). */
+#define I2C_SMBUS_QUICK                        0
+#define I2C_SMBUS_BYTE                 1
+#define I2C_SMBUS_BYTE_DATA            2
+#define I2C_SMBUS_WORD_DATA            3
+#define I2C_SMBUS_PROC_CALL            4
+#define I2C_SMBUS_BLOCK_DATA           5
+#define I2C_SMBUS_I2C_BLOCK_BROKEN     6
+#define I2C_SMBUS_BLOCK_PROC_CALL      7
+#define I2C_SMBUS_I2C_BLOCK_DATA       8
+
+/* Defines to determine what functionality is present */
+#define I2C_FUNC_I2C                           0x00000001
+#define I2C_FUNC_10BIT_ADDR                    0x00000002
+#define I2C_FUNC_PROTOCOL_MANGLING             0x00000004
+#define I2C_FUNC_SMBUS_PEC                     0x00000008
+#define I2C_FUNC_SMBUS_BLOCK_PROC_CALL         0x00008000
+#define I2C_FUNC_SMBUS_QUICK                   0x00010000
+#define I2C_FUNC_SMBUS_READ_BYTE               0x00020000
+#define I2C_FUNC_SMBUS_WRITE_BYTE              0x00040000
+#define I2C_FUNC_SMBUS_READ_BYTE_DATA          0x00080000
+#define I2C_FUNC_SMBUS_WRITE_BYTE_DATA         0x00100000
+#define I2C_FUNC_SMBUS_READ_WORD_DATA          0x00200000
+#define I2C_FUNC_SMBUS_WRITE_WORD_DATA         0x00400000
+#define I2C_FUNC_SMBUS_PROC_CALL               0x00800000
+#define I2C_FUNC_SMBUS_READ_BLOCK_DATA         0x01000000
+#define I2C_FUNC_SMBUS_WRITE_BLOCK_DATA        0x02000000
+#define I2C_FUNC_SMBUS_READ_I2C_BLOCK          0x04000000
+#define I2C_FUNC_SMBUS_WRITE_I2C_BLOCK         0x08000000
+
+/*
+ * This is needed for ioctl_or_perror_and_die() since it only accepts pointers.
+ */
+static void *itoptr(int i)
+{
+       return (void*)(intptr_t)i;
+}
+
+static int32_t i2c_smbus_access(int fd, char read_write, uint8_t cmd,
+                               int size, union i2c_smbus_data *data)
+{
+       struct i2c_smbus_ioctl_data args;
+
+       args.read_write = read_write;
+       args.command = cmd;
+       args.size = size;
+       args.data = data;
+
+       return ioctl(fd, I2C_SMBUS, &args);
+}
+
+static int32_t i2c_smbus_read_byte(int fd)
+{
+       union i2c_smbus_data data;
+       int err;
+
+       err = i2c_smbus_access(fd, I2C_SMBUS_READ, 0, I2C_SMBUS_BYTE, &data);
+       if (err < 0)
+               return err;
+
+       return 0xff & data.byte;
+}
+
+static int32_t i2c_smbus_write_byte(int fd, uint8_t val)
+{
+       return i2c_smbus_access(fd, I2C_SMBUS_WRITE,
+                               val, I2C_SMBUS_BYTE, NULL);
+}
+
+static int32_t i2c_smbus_read_byte_data(int fd, uint8_t cmd)
+{
+       union i2c_smbus_data data;
+       int err;
+
+       err = i2c_smbus_access(fd, I2C_SMBUS_READ, cmd,
+                              I2C_SMBUS_BYTE_DATA, &data);
+       if (err < 0)
+               return err;
+
+       return 0xff & data.byte;
+}
+
+static int32_t i2c_smbus_read_word_data(int fd, uint8_t cmd)
+{
+       union i2c_smbus_data data;
+       int err;
+
+       err = i2c_smbus_access(fd, I2C_SMBUS_READ, cmd,
+                              I2C_SMBUS_WORD_DATA, &data);
+       if (err < 0)
+               return err;
+
+       return 0xffff & data.word;
+}
+
+#if ENABLE_I2CSET
+static int32_t i2c_smbus_write_byte_data(int file,
+                                        uint8_t cmd, uint8_t value)
+{
+       union i2c_smbus_data data;
+
+       data.byte = value;
+
+       return i2c_smbus_access(file, I2C_SMBUS_WRITE, cmd,
+                               I2C_SMBUS_BYTE_DATA, &data);
+}
+
+static int32_t i2c_smbus_write_word_data(int file, uint8_t cmd, uint16_t value)
+{
+       union i2c_smbus_data data;
+
+       data.word = value;
+
+       return i2c_smbus_access(file, I2C_SMBUS_WRITE, cmd,
+                               I2C_SMBUS_WORD_DATA, &data);
+}
+
+static int32_t i2c_smbus_write_block_data(int file, uint8_t cmd,
+                                  uint8_t length, const uint8_t *values)
+{
+       union i2c_smbus_data data;
+
+       if (length > I2C_SMBUS_BLOCK_MAX)
+               length = I2C_SMBUS_BLOCK_MAX;
+
+       memcpy(data.block+1, values, length);
+       data.block[0] = length;
+
+       return i2c_smbus_access(file, I2C_SMBUS_WRITE, cmd,
+                               I2C_SMBUS_BLOCK_DATA, &data);
+}
+
+static int32_t i2c_smbus_write_i2c_block_data(int file, uint8_t cmd,
+                                      uint8_t length, const uint8_t *values)
+{
+       union i2c_smbus_data data;
+
+       if (length > I2C_SMBUS_BLOCK_MAX)
+               length = I2C_SMBUS_BLOCK_MAX;
+
+       memcpy(data.block+1, values, length);
+       data.block[0] = length;
+
+       return i2c_smbus_access(file, I2C_SMBUS_WRITE, cmd,
+                               I2C_SMBUS_I2C_BLOCK_BROKEN, &data);
+}
+#endif /* ENABLE_I2CSET */
+
+#if ENABLE_I2CDUMP
+/*
+ * Returns the number of bytes read, vals must hold at
+ * least I2C_SMBUS_BLOCK_MAX bytes.
+ */
+static int32_t i2c_smbus_read_block_data(int fd, uint8_t cmd, uint8_t *vals)
+{
+       union i2c_smbus_data data;
+       int i, err;
+
+       err = i2c_smbus_access(fd, I2C_SMBUS_READ, cmd,
+                              I2C_SMBUS_BLOCK_DATA, &data);
+       if (err < 0)
+               return err;
+
+       for (i = 1; i <= data.block[0]; i++)
+               vals[i-1] = data.block[i];
+       return data.block[0];
+}
+
+static int32_t i2c_smbus_read_i2c_block_data(int fd, uint8_t cmd,
+                                            uint8_t len, uint8_t *vals)
+{
+       union i2c_smbus_data data;
+       int i, err;
+
+       if (len > I2C_SMBUS_BLOCK_MAX)
+               len = I2C_SMBUS_BLOCK_MAX;
+       data.block[0] = len;
+
+       err = i2c_smbus_access(fd, I2C_SMBUS_READ, cmd,
+                              len == 32 ? I2C_SMBUS_I2C_BLOCK_BROKEN :
+                                          I2C_SMBUS_I2C_BLOCK_DATA, &data);
+       if (err < 0)
+               return err;
+
+       for (i = 1; i <= data.block[0]; i++)
+               vals[i-1] = data.block[i];
+       return data.block[0];
+}
+#endif /* ENABLE_I2CDUMP */
+
+static int i2c_bus_lookup(const char *bus_str)
+{
+       return xstrtoi_range(bus_str, 10, 0, 0xfffff);
+}
+
+static int i2c_parse_bus_addr(const char *addr_str)
+{
+       /* Slave address must be in range 0x03 - 0x77. */
+       return xstrtoi_range(addr_str, 16, 0x03, 0x77);
+}
+
+#if ENABLE_I2CGET || ENABLE_I2CSET
+static int i2c_parse_data_addr(const char *data_addr)
+{
+       /* Data address must be an 8 bit integer. */
+       return xstrtoi_range(data_addr, 16, 0, 0xff);
+}
+#endif /* ENABLE_I2CGET || ENABLE_I2CSET */
+
+/*
+ * Opens the device file associated with given i2c bus.
+ *
+ * Upstream i2c-tools also support opening devices by i2c bus name
+ * but we drop it here for size reduction.
+ */
+static int i2c_dev_open(int i2cbus)
+{
+       char filename[32];
+       int fd;
+
+       snprintf(filename, sizeof(filename), "/dev/i2c-%d", i2cbus);
+       fd = open(filename, O_RDWR);
+       if (fd < 0 && errno == ENOENT) {
+               snprintf(filename, sizeof(filename), "/dev/i2c/%d", i2cbus);
+               fd = open(filename, O_RDWR);
+       }
+
+       if (fd < 0)
+               bb_perror_msg_and_die(
+                       "Could not open /dev/i2c-%d or /dev/i2c/%d",
+                       i2cbus, i2cbus);
+
+       return fd;
+}
+
+static void i2c_set_slave_addr(int fd, int addr, int force)
+{
+       ioctl_or_perror_and_die(fd, force ? I2C_SLAVE_FORCE : I2C_SLAVE,
+                               itoptr(addr),
+                               "Could not set address to 0x%02x", addr);
+}
+
+static void i2c_set_pec(int fd, int pec)
+{
+       ioctl_or_perror_and_die(fd, I2C_PEC,
+                               itoptr(pec ? 1 : 0),
+                               "Could not set PEC");
+}
+
+/* Size reducing helpers for xxx_check_funcs(). */
+static void get_funcs_matrix(int fd, unsigned long *funcs)
+{
+       ioctl_or_perror_and_die(fd, I2C_FUNCS, funcs,
+                       "Could not get the adapter functionality matrix");
+}
+
+static void check_funcs_test_end(int funcs, int pec, const char *err)
+{
+       if (pec && !(funcs & (I2C_FUNC_SMBUS_PEC | I2C_FUNC_I2C)))
+               fprintf(stderr,
+                       "Warning: Adapter does not seem to support PEC\n");
+
+       if (err)
+               bb_error_msg_and_die("Adapter does not have %s capability",
+                                    err);
+}
+
+/*
+ * The below functions emit an error message and exit if the adapter doesn't
+ * support desired functionalities.
+ */
+#if ENABLE_I2CGET || ENABLE_I2CDUMP
+static void check_read_funcs(int fd, int mode, int data_addr, int pec)
+{
+       unsigned long funcs;
+       const char *err = NULL;
+
+       get_funcs_matrix(fd, &funcs);
+       switch (mode) {
+       case I2C_SMBUS_BYTE:
+               if (!(funcs & I2C_FUNC_SMBUS_READ_BYTE)) {
+                       err = "SMBus receive byte";
+                       break;
+               }
+               if (data_addr >= 0 && !(funcs & I2C_FUNC_SMBUS_WRITE_BYTE))
+                       err = "SMBus send byte";
+               break;
+       case I2C_SMBUS_BYTE_DATA:
+               if (!(funcs & I2C_FUNC_SMBUS_READ_BYTE_DATA))
+                       err = "SMBus read byte";
+               break;
+       case I2C_SMBUS_WORD_DATA:
+               if (!(funcs & I2C_FUNC_SMBUS_READ_WORD_DATA))
+                       err = "SMBus read word";
+               break;
+#if ENABLE_I2CDUMP
+       case I2C_SMBUS_BLOCK_DATA:
+               if (!(funcs & I2C_FUNC_SMBUS_READ_BLOCK_DATA))
+                       err = "SMBus block read";
+               break;
+
+       case I2C_SMBUS_I2C_BLOCK_DATA:
+               if (!(funcs & I2C_FUNC_SMBUS_READ_I2C_BLOCK))
+                       err = "I2C block read";
+               break;
+#endif /* ENABLE_I2CDUMP */
+       default:
+               bb_error_msg_and_die("Programmer goofed!");
+       }
+       check_funcs_test_end(funcs, pec, err);
+}
+#endif /* ENABLE_I2CGET || ENABLE_I2CDUMP */
+
+#if ENABLE_I2CSET
+static void check_write_funcs(int fd, int mode, int pec)
+{
+       unsigned long funcs;
+       const char *err = NULL;
+
+       get_funcs_matrix(fd, &funcs);
+       switch (mode) {
+       case I2C_SMBUS_BYTE:
+               if (!(funcs & I2C_FUNC_SMBUS_WRITE_BYTE))
+                       err = "SMBus send byte";
+               break;
+
+       case I2C_SMBUS_BYTE_DATA:
+               if (!(funcs & I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
+                       err = "SMBus write byte";
+               break;
+
+       case I2C_SMBUS_WORD_DATA:
+               if (!(funcs & I2C_FUNC_SMBUS_WRITE_WORD_DATA))
+                       err = "SMBus write word";
+               break;
+
+       case I2C_SMBUS_BLOCK_DATA:
+               if (!(funcs & I2C_FUNC_SMBUS_WRITE_BLOCK_DATA))
+                       err = "SMBus block write";
+               break;
+       case I2C_SMBUS_I2C_BLOCK_DATA:
+               if (!(funcs & I2C_FUNC_SMBUS_WRITE_I2C_BLOCK))
+                       err = "I2C block write";
+               break;
+       }
+       check_funcs_test_end(funcs, pec, err);
+}
+#endif /* ENABLE_I2CSET */
+
+static void confirm_or_abort(void)
+{
+       if (!user_confirm("Continue?"))
+               bb_error_msg_and_die("Aborting");
+}
+
+/*
+ * Return only if user confirms the action, abort otherwise.
+ *
+ * The messages displayed here are much less elaborate than their i2c-tools
+ * counterparts - this is done for size reduction.
+ */
+static void confirm_action(int bus_addr, int mode, int data_addr, int pec)
+{
+       fprintf(stderr, "WARNING! This program can confuse your I2C bus\n");
+
+       /* Don't let the user break his/her EEPROMs */
+       if (bus_addr >= 0x50 && bus_addr <= 0x57 && pec) {
+               fprintf(stderr, "This is I2C not smbus - using PEC on I2C "
+                       "devices may result in data loss. Aborting.\n");
+               xfunc_die();
+       }
+
+       if (mode == I2C_SMBUS_BYTE && data_addr >= 0 && pec)
+               fprintf(stderr, "WARNING! May interpret a write byte command "
+                       "with PEC as a write byte data command!\n");
+
+       if (pec)
+               fprintf(stderr, "PEC checking enabled.\n");
+
+       confirm_or_abort();
+}
+
+#if ENABLE_I2CGET
+int i2cget_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int i2cget_main(int argc, char **argv)
+{
+       static const unsigned opt_f = (1 << 0), opt_y = (1 << 1);
+       static const char *const optstr = "fy";
+
+       int bus_num, bus_addr, data_addr = -1, status;
+       int mode = I2C_SMBUS_BYTE, pec = 0, fd;
+       unsigned opts;
+
+       opts = getopt32(argv, optstr);
+       argv += optind;
+       argc -= optind;
+
+       if (argc < 2)
+               bb_show_usage();
+
+       bus_num = i2c_bus_lookup(argv[0]);
+       bus_addr = i2c_parse_bus_addr(argv[1]);
+
+       if (argc > 2) {
+               data_addr = i2c_parse_data_addr(argv[2]);
+               mode = I2C_SMBUS_BYTE_DATA;
+       }
+
+       if (argc > 3) {
+               switch (argv[3][0]) {
+               case 'b':       /* Already set */               break;
+               case 'w':       mode = I2C_SMBUS_WORD_DATA;     break;
+               case 'c':       mode = I2C_SMBUS_BYTE;          break;
+               default:
+                       bb_error_msg("Invalid mode");
+                       bb_show_usage();
+               }
+               pec = argv[3][1] == 'p';
+       }
+
+       fd = i2c_dev_open(bus_num);
+       check_read_funcs(fd, mode, data_addr, pec);
+       i2c_set_slave_addr(fd, bus_addr, opts & opt_f);
+
+       if (!(opts & opt_y))
+               confirm_action(bus_addr, mode, data_addr, pec);
+
+       if (pec)
+               i2c_set_pec(fd, 1);
+
+       switch (mode) {
+       case I2C_SMBUS_BYTE:
+               if (data_addr >= 0) {
+                       status = i2c_smbus_write_byte(fd, data_addr);
+                       if (status < 0)
+                               fprintf(stderr, "Warning - write failed\n");
+               }
+               status = i2c_smbus_read_byte(fd);
+               break;
+       case I2C_SMBUS_WORD_DATA:
+               status = i2c_smbus_read_word_data(fd, data_addr);
+               break;
+       default: /* I2C_SMBUS_BYTE_DATA */
+               status = i2c_smbus_read_byte_data(fd, data_addr);
+       }
+       close(fd);
+
+       if (status < 0)
+               bb_perror_msg_and_die("Read failed");
+
+       printf("0x%0*x\n", mode == I2C_SMBUS_WORD_DATA ? 4 : 2, status);
+
+       return 0;
+}
+#endif /* ENABLE_I2CGET */
+
+#if ENABLE_I2CSET
+int i2cset_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int i2cset_main(int argc, char **argv)
+{
+       static const unsigned opt_f = (1 << 0), opt_y = (1 << 1),
+                             opt_m = (1 << 2), opt_r = (1 << 3);
+       static const char *const optstr = "fym:r";
+
+       int bus_num, bus_addr, data_addr, mode = I2C_SMBUS_BYTE, pec = 0;
+       int val, blen = 0, mask = 0, fd, status;
+       unsigned char block[I2C_SMBUS_BLOCK_MAX];
+       char *opt_m_arg = NULL;
+       unsigned opts;
+
+       opts = getopt32(argv, optstr, &opt_m_arg);
+       argv += optind;
+       argc -= optind;
+
+       if (argc < 3)
+               bb_show_usage();
+
+       bus_num = i2c_bus_lookup(argv[0]);
+       bus_addr = i2c_parse_bus_addr(argv[1]);
+       data_addr = i2c_parse_data_addr(argv[2]);
+
+       if (argc > 3) {
+               if (argc == 4 && argv[3][0] != 'c') {
+                       mode = I2C_SMBUS_BYTE_DATA; /* Implicit b */
+               } else {
+                       switch (argv[argc-1][0]) {
+                       case 'c': /* Already set */                     break;
+                       case 'b': mode = I2C_SMBUS_BYTE_DATA;           break;
+                       case 'w': mode = I2C_SMBUS_WORD_DATA;           break;
+                       case 's': mode = I2C_SMBUS_BLOCK_DATA;          break;
+                       case 'i': mode = I2C_SMBUS_I2C_BLOCK_DATA;      break;
+                       default:
+                               bb_error_msg("Invalid mode");
+                               bb_show_usage();
+                       }
+
+                       pec = argv[argc-1][1] == 'p';
+                       if (mode == I2C_SMBUS_BLOCK_DATA ||
+                                       mode == I2C_SMBUS_I2C_BLOCK_DATA) {
+                               if (pec && mode == I2C_SMBUS_I2C_BLOCK_DATA)
+                                       bb_error_msg_and_die(
+                                               "PEC not supported for I2C "
+                                               "block writes!");
+                               if (opts & opt_m)
+                                       bb_error_msg_and_die(
+                                               "Mask not supported for block "
+                                               "writes!\n");
+                       }
+               }
+       }
+
+       /* Prepare the value(s) to be written according to current mode. */
+       switch (mode) {
+       case I2C_SMBUS_BYTE_DATA:
+               val = xstrtoi_range(argv[3], 0, 0, 0xff);
+               break;
+       case I2C_SMBUS_WORD_DATA:
+               val = xstrtoi_range(argv[3], 0, 0, 0xffff);
+               break;
+       case I2C_SMBUS_BLOCK_DATA:
+       case I2C_SMBUS_I2C_BLOCK_DATA:
+               for (blen = 3; blen < (argc - 1); blen++)
+                       block[blen] = xstrtoi_range(argv[blen], 0, 0, 0xff);
+               val = -1;
+               break;
+       default:
+               val = -1;
+               break;
+       }
+
+       if (opts & opt_m) {
+               mask = xstrtoi_range(opt_m_arg, 0, 0,
+                               (mode == I2C_SMBUS_BYTE ||
+                                mode == I2C_SMBUS_BYTE_DATA) ? 0xff : 0xffff);
+       }
+
+       fd = i2c_dev_open(bus_num);
+       check_write_funcs(fd, mode, pec);
+       i2c_set_slave_addr(fd, bus_addr, opts & opt_f);
+
+       if (!(opts & opt_y))
+               confirm_action(bus_addr, mode, data_addr, pec);
+
+       /*
+        * If we're using mask - read the current value here and adjust the
+        * value to be written.
+        */
+       if (opts & opt_m) {
+               int tmpval;
+
+               switch (mode) {
+               case I2C_SMBUS_BYTE:
+                       tmpval = i2c_smbus_read_byte(fd);
+                       break;
+               case I2C_SMBUS_WORD_DATA:
+                       tmpval = i2c_smbus_read_word_data(fd, data_addr);
+                       break;
+               default:
+                       tmpval = i2c_smbus_read_byte_data(fd, data_addr);
+               }
+
+               if (tmpval < 0)
+                       bb_perror_msg_and_die("Failed to read old value");
+
+               val = (val & mask) | (tmpval & ~mask);
+
+               if (!(opts & opt_y)) {
+                       fprintf(stderr, "Old value 0x%0*x, write mask "
+                               "0x%0*x: Will write 0x%0*x to register "
+                               "0x%02x\n",
+                               mode == I2C_SMBUS_WORD_DATA ? 4 : 2, tmpval,
+                               mode == I2C_SMBUS_WORD_DATA ? 4 : 2, mask,
+                               mode == I2C_SMBUS_WORD_DATA ? 4 : 2, val,
+                               data_addr);
+
+                       confirm_or_abort();
+               }
+       }
+
+       if (pec)
+               i2c_set_pec(fd, 1);
+
+       switch (mode) {
+       case I2C_SMBUS_BYTE:
+               status = i2c_smbus_write_byte(fd, data_addr);
+               break;
+       case I2C_SMBUS_WORD_DATA:
+               status = i2c_smbus_write_word_data(fd, data_addr, val);
+               break;
+       case I2C_SMBUS_BLOCK_DATA:
+               status = i2c_smbus_write_block_data(fd, data_addr,
+                                                   blen, block);
+               break;
+       case I2C_SMBUS_I2C_BLOCK_DATA:
+               status = i2c_smbus_write_i2c_block_data(fd, data_addr,
+                                                       blen, block);
+               break;
+       default: /* I2C_SMBUS_BYTE_DATA */
+               status = i2c_smbus_write_byte_data(fd, data_addr, val);
+               break;
+       }
+       if (status < 0)
+               bb_perror_msg_and_die("Write failed\n");
+
+       if (pec)
+               i2c_set_pec(fd, 0); /* Clear PEC */
+
+       /* No readback required - we're done. */
+       if (!(opts & opt_r))
+               return 0;
+
+       switch (mode) {
+       case I2C_SMBUS_BYTE:
+               status = i2c_smbus_read_byte(fd);
+               val = data_addr;
+               break;
+       case I2C_SMBUS_WORD_DATA:
+               status = i2c_smbus_read_word_data(fd, data_addr);
+               break;
+       default: /* I2C_SMBUS_BYTE_DATA */
+               status = i2c_smbus_read_byte_data(fd, data_addr);
+       }
+
+       if (status < 0) {
+               printf("Warning - readback failed\n");
+       } else
+       if (status != val) {
+               printf("Warning - data mismatch - wrote "
+                      "0x%0*x, read back 0x%0*x\n",
+                      mode == I2C_SMBUS_WORD_DATA ? 4 : 2, val,
+                      mode == I2C_SMBUS_WORD_DATA ? 4 : 2, status);
+       } else {
+               printf("Value 0x%0*x written, readback matched\n",
+                      mode == I2C_SMBUS_WORD_DATA ? 4 : 2, val);
+       }
+
+       return 0;
+}
+#endif /* ENABLE_I2CSET */
+
+#if ENABLE_I2CDUMP
+int i2cdump_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int i2cdump_main(int argc, char **argv)
+{
+       static const unsigned opt_f = (1 << 0), opt_y = (1 << 1),
+                             opt_r = (1 << 2);
+       static const char *const optstr = "fyr:";
+
+       int bus_num, bus_addr, mode = I2C_SMBUS_BYTE_DATA, even = 0, pec = 0;
+       int first = 0x00, last = 0xff, fd, i, j, res, blen = 0, tmp;
+       unsigned char cblock[I2C_SMBUS_BLOCK_MAX + I2C_MAX_REGS];
+       unsigned char block[I2C_SMBUS_BLOCK_MAX];
+       char *opt_r_str, *dash;
+       unsigned opts;
+
+       opts = getopt32(argv, optstr, &opt_r_str);
+       argv += optind;
+       argc -= optind;
+
+       if (argc < 2)
+               bb_show_usage();
+
+       bus_num = i2c_bus_lookup(argv[0]);
+       bus_addr = i2c_parse_bus_addr(argv[1]);
+
+       if (argc > 2) {
+               switch (argv[2][0]) {
+               case 'b': /* Already set */                     break;
+               case 'c': mode = I2C_SMBUS_BYTE;                break;
+               case 'w': mode = I2C_SMBUS_WORD_DATA;           break;
+               case 'W':
+                       mode = I2C_SMBUS_WORD_DATA;
+                       even = 1;
+                       break;
+               case 's': mode = I2C_SMBUS_BLOCK_DATA;          break;
+               case 'i': mode = I2C_SMBUS_I2C_BLOCK_DATA;      break;
+               default:
+                       bb_error_msg_and_die("Invalid mode");
+               }
+
+               if (argv[2][1] == 'p') {
+                       if (argv[2][0] == 'W' || argv[2][0] == 'i') {
+                               bb_error_msg_and_die(
+                                       "pec not supported for -W and -i");
+                       } else {
+                               pec = 1;
+                       }
+               }
+       }
+
+       if (opts & opt_r) {
+               first = strtol(opt_r_str, &dash, 0);
+               if (dash == opt_r_str || *dash != '-' ||
+                   first < 0 || first > 0xff)
+                       bb_error_msg_and_die("Invalid range");
+               last = xstrtoi_range(++dash, 0, first, 0xff);
+
+               /* Range is not available for every mode */
+               switch (mode) {
+               case I2C_SMBUS_BYTE:
+               case I2C_SMBUS_BYTE_DATA:
+                       break;
+               case I2C_SMBUS_WORD_DATA:
+                       if (!even || (!(first % 2) && last % 2))
+                               break;
+                       /* Fall through */
+               default:
+                       bb_error_msg_and_die(
+                               "Range not compatible with selected mode!");
+               }
+       }
+
+       fd = i2c_dev_open(bus_num);
+       check_read_funcs(fd, mode, -1 /* data_addr */, pec);
+       i2c_set_slave_addr(fd, bus_addr, opts & opt_f);
+
+       if (pec)
+               i2c_set_pec(fd, 1);
+
+       if (!(opts & opt_y))
+               confirm_action(bus_addr, mode, -1 /* data_addr */, pec);
+
+       /* All but word data */
+       if (mode != I2C_SMBUS_WORD_DATA || even) {
+               /*
+                * FIXME This section has been ported from upstream i2cdump.
+                * It has been reworked a bit but is still pretty spaghetti
+                * and needs splitting into several functions.
+                */
+               if (mode == I2C_SMBUS_BLOCK_DATA ||
+                   mode == I2C_SMBUS_I2C_BLOCK_DATA) {
+                       res = i2c_smbus_read_block_data(fd, 0, cblock);
+                       blen = res;
+               } else {
+                       for (res = 0; res < I2C_MAX_REGS; res += tmp) {
+                               tmp = i2c_smbus_read_i2c_block_data(
+                                       fd, res, I2C_SMBUS_BLOCK_MAX,
+                                       cblock + res);
+                               if (tmp < 0) {
+                                       bb_error_msg_and_die(
+                                               "Block read failed");
+                               }
+                       }
+                       if (res >= I2C_MAX_REGS)
+                               res = I2C_MAX_REGS;
+                       for (i = 0; i < res; i++)
+                               block[i] = cblock[i];
+                       if (mode != I2C_SMBUS_BLOCK_DATA)
+                               for (i = res; i < I2C_MAX_REGS; i++)
+                                       cblock[i] = -1;
+               }
+
+               if (mode == I2C_SMBUS_BYTE) {
+                       res = i2c_smbus_write_byte(fd, first);
+                       if (res < 0)
+                               bb_perror_msg_and_die(
+                                       "Error: Write start address failed");
+               }
+
+               printf("     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f"
+                      "    0123456789abcdef\n");
+
+               for (i = 0; i < I2C_MAX_REGS; i += 0x10) {
+                       if (mode == I2C_SMBUS_BLOCK_DATA && i >= blen)
+                               break;
+                       if (i/16 < first/16)
+                               continue;
+                       if (i/16 > last/16)
+                               break;
+
+                       printf("%02x: ", i);
+                       for (j = 0; j < 16; j++) {
+                               fflush(stdout);
+                               /* Skip unwanted registers */
+                               if (i+j < first || i+j > last) {
+                                       printf("   ");
+                                       if (mode == I2C_SMBUS_WORD_DATA) {
+                                               printf("   ");
+                                               j++;
+                                       }
+                                       continue;
+                               }
+
+                               switch (mode) {
+                               case I2C_SMBUS_BYTE_DATA:
+                                       res = i2c_smbus_read_byte_data(fd, i+j);
+                                       block[i+j] = res;
+                                       break;
+                               case I2C_SMBUS_WORD_DATA:
+                                       res = i2c_smbus_read_word_data(fd, i+j);
+                                       if (res < 0) {
+                                               block[i+j] = res;
+                                               block[i+j+1] = res;
+                                       } else {
+                                               block[i+j] = res & 0xff;
+                                               block[i+j+1] = res >> 8;
+                                       }
+                                       break;
+                               case I2C_SMBUS_BYTE:
+                                       res = i2c_smbus_read_byte(fd);
+                                       block[i+j] = res;
+                                       break;
+                               default:
+                                       res = block[i+j];
+                               }
+
+                               if (mode == I2C_SMBUS_BLOCK_DATA &&
+                                   i+j >= blen) {
+                                       printf("   ");
+                               } else if (res < 0) {
+                                       printf("XX ");
+                                       if (mode == I2C_SMBUS_WORD_DATA)
+                                               printf("XX ");
+                               } else {
+                                       printf("%02x ", block[i+j]);
+                                       if (mode == I2C_SMBUS_WORD_DATA)
+                                               printf("%02x ", block[i+j+1]);
+                               }
+
+                               if (mode == I2C_SMBUS_WORD_DATA)
+                                       j++;
+                       }
+                       printf("   ");
+
+                       for (j = 0; j < 16; j++) {
+                               if (mode == I2C_SMBUS_BLOCK_DATA && i+j >= blen)
+                                       break;
+                               /* Skip unwanted registers */
+                               if (i+j < first || i+j > last) {
+                                       printf(" ");
+                                       continue;
+                               }
+
+                               res = block[i+j];
+                               if (res < 0) {
+                                       printf("X");
+                               } else if ((res & 0xff) == 0x00 ||
+                                          (res & 0xff) == 0xff) {
+                                       printf(".");
+                               } else if ((res & 0xff) < 32 ||
+                                          (res & 0xff) >= 127) {
+                                       printf("?");
+                               } else {
+                                       printf("%c", res & 0xff);
+                               }
+                       }
+                       printf("\n");
+               }
+       } else {
+               /* Word data */
+               printf("     0,8  1,9  2,a  3,b  4,c  5,d  6,e  7,f\n");
+               for (i = 0; i < 256; i += 8) {
+                       if (i/8 < first/8)
+                               continue;
+                       if (i/8 > last/8)
+                               break;
+
+                       printf("%02x: ", i);
+                       for (j = 0; j < 8; j++) {
+                               /* Skip unwanted registers */
+                               if (i+j < first || i+j > last) {
+                                       printf("     ");
+                                       continue;
+                               }
+
+                               res = i2c_smbus_read_word_data(fd, i+j);
+                               if (res < 0)
+                                       printf("XXXX ");
+                               else
+                                       printf("%04x ", res & 0xffff);
+                       }
+                       printf("\n");
+               }
+       }
+
+       return 0;
+}
+#endif /* ENABLE_I2CDUMP */
-- 
2.1.3

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