[RFC] new applets: i2c-tools
walter harms
wharms at bfs.de
Tue Dec 9 17:09:54 UTC 2014
hi,
i did not try compile, i was only watching ...
hope the comments will help
re,
wh
Am 09.12.2014 15:51, schrieb Bartosz Golaszewski:
> Hi,
>
> I've started porting i2c-tools to busybox.
>
> This patch implements i2cget together with necessary library functions - a lot
> of this code can be reused in other i2c utils.
>
> Bloatcheck:
>
> function old new delta
> i2cget_main - 1464 +1464
> .rodata 138898 139779 +881
> packed_usage 29706 29825 +119
> i2c_smbus_access - 48 +48
> run_applet_no_and_exit 588 596 +8
> err_msg_and_usage_and_die - 8 +8
> applet_names 2451 2458 +7
> applet_main 1428 1432 +4
> applet_nameofs 714 716 +2
> ------------------------------------------------------------------------------
> (add/remove: 4/0 grow/shrink: 6/0 up/down: 2541/0) Total: 2541 bytes
>
> I'd like to get some comments before implementing the rest.
>
> Signed-off-by: Bartosz Golaszewski <bartekgola at gmail.com>
> ---
> miscutils/i2c_tools.c | 451 ++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 451 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..3036ae6
> --- /dev/null
> +++ b/miscutils/i2c_tools.c
> @@ -0,0 +1,451 @@
> +/* 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 <bartekgola at gmail.com>
> + *
> + * 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.
> +
> +//applet:IF_I2CGET(APPLET(i2cget, BB_DIR_USR_SBIN, BB_SUID_DROP))
> +
> +//kbuild:lib-$(CONFIG_I2CGET) += i2c_tools.o
> +
> +//usage:#define i2cget_trivial_usage
> +//usage: "[-f] [-y] I2CBUS 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 -f - force access to device"
> +//usage: "\n -y - disable interactive mode"
> +
> +#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
> +
> +/* 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 pointer.
> + */
> +#define INT_TO_PTR(i) ((void*)((long)i))
> +
> +static int32_t i2c_smbus_access(int fd, char read_write, uint8_t command,
> + int size, union i2c_smbus_data *data)
> +{
> + struct i2c_smbus_ioctl_data args;
> +
> + args.read_write = read_write;
> + args.command = command;
> + 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 0x0FF & data.byte;
> +}
nitpicking:
is that 0x0ff needed ? so far i can see data.byte should be uint8_t ?
> +
> +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 0x0FF & data.byte;
> +}
as i2c_smbus_read_byte; 0x0ff is confusing me 0x00ff or 0xff
> +
> +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 0x0FFFF & data.word;
> +}
> +
> +static void NORETURN err_msg_and_usage_and_die(const char *msg)
> +{
> + bb_error_msg(msg);
> + bb_show_usage();
> +}
> +
> +static int i2c_bus_lookup(const char *bus_str)
> +{
> + unsigned long i2cbus;
> + char *end;
> +
> + i2cbus = bb_strtoul(bus_str, &end, 10);
> + if (*end || !*bus_str)
> + err_msg_and_usage_and_die("Bus address is not a number");
> + if (i2cbus > 0xfffff)
> + err_msg_and_usage_and_die("Bus address out of range");
> +
> + return i2cbus;
> +}
> +
> +static int i2c_parse_addr(const char *addr_str)
> +{
> + long addr;
> + char *end;
> +
> + addr = bb_strtol(addr_str, &end, 16);
> + if (*end || !*addr_str)
> + err_msg_and_usage_and_die("Chip address is not a number");
> + if (addr < 0x03 || addr > 0x77)
> + err_msg_and_usage_and_die("Chip address out of range");
> +
> + return addr;
> +}
> +
> +/*
> + * Opens the device file associated with given i2c bus.
> + *
> + * i2cbus - number of the i2c bus
> + * filename - buffer to store the filename
> + * len - buffer length
> + */
> +static int i2c_dev_open(int i2cbus, char *filename, size_t len)
> +{
> + int fd;
> +
> + snprintf(filename, len, "/dev/i2c-%d", i2cbus);
> +
> + fd = open(filename, O_RDWR);
> + if (fd < 0 && errno == ENOENT) {
> + /* Older kernels register the devices files this way. */
> + snprintf(filename, len, "/dev/i2c/%d", i2cbus);
> + fd = open(filename, O_RDWR);
> + }
> +
> + if (fd < 0)
> + bb_perror_msg_and_die("Could not open file: "
> + "/dev/i2c-%d or /dev/i2c/%d",
> + i2cbus, i2cbus);
> +
> + return fd;
> +}
could you please explain shortly why you have a external buffer here ?
you could easly do
filename=xasprintf("/dev/i2c-%d", i2cbus);
or
char filename[32];
or
....
btw:
bb_perror_msg_and_die("Could not open file: "Could not open file: %s",filename) would work also ?
> +
> +static void i2c_set_slave_addr(int fd, int addr, int force)
> +{
> + ioctl_or_perror_and_die(fd, force ? I2C_SLAVE_FORCE : I2C_SLAVE,
> + INT_TO_PTR(addr),
> + "Could not set address to 0x%02x", addr);
> +}
> +
> +static void check_funcs(int fd, int mode, int data_addr, int pec)
> +{
> + unsigned long funcs;
> + const char *err;
> +
> + ioctl_or_perror_and_die(fd, I2C_FUNCS, &funcs,
> + "Could not get the adapter functionality matrix");
> +
> + switch (mode) {
> + case I2C_SMBUS_BYTE:
> + if (!(funcs & I2C_FUNC_SMBUS_READ_BYTE)) {
> + err = "SMBus receive byte";
> + goto err_out;
> + }
> + if (data_addr >= 0 && !(funcs & I2C_FUNC_SMBUS_WRITE_BYTE)) {
> + err = "SMBus send byte";
> + goto err_out;
> + }
> + break;
> + case I2C_SMBUS_BYTE_DATA:
> + if (!(funcs & I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
> + err = "SMBus read byte";
> + goto err_out;
> + }
> + break;
> + case I2C_SMBUS_WORD_DATA:
> + if (!(funcs & I2C_FUNC_SMBUS_READ_WORD_DATA)) {
> + err = "SMBus read word";
> + goto err_out;
> + }
> + break;
> + }
> +
> + if (pec && !(funcs & (I2C_FUNC_SMBUS_PEC | I2C_FUNC_I2C)))
> + fprintf(stderr,
> + "Warning: Adapter does not seem to support PEC\n");
> +
> + return;
> +
> +err_out:
> + bb_error_msg_and_die("Adapter does not have %s capability", err);
> +}
> +
> +/* Return 1 if we should continue, 0 if we should abort */
> +static int user_ack(int def)
> +{
> + char s[2];
> + int ret;
> +
> + if (!fgets(s, 2, stdin))
> + return 0; /* Nack by default */
i would use read(STDIN_FILENO,s,2);
> +
> + switch (s[0]) {
tolower(s[0]); ? just to avoild these double labels.
> + case 'y':
> + case 'Y':
> + ret = 1;
> + break;
> + case 'n':
> + case 'N':
> + ret = 0;
> + break;
> + default:
> + ret = def;
> + }
> +
> + /* Flush extra characters */
> + while (s[0] != '\n') {
> + int c = fgetc(stdin);
> + if (c == EOF) {
> + ret = 0;
> + break;
> + }
> + s[0] = c;
> + }
> +
> + return ret;
> +}
> +
> +/*
> + * 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)
> +{
> + int dont = 0;
> +
> + 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");
> + dont++;
> + }
> +
> + if (pec)
> + fprintf(stderr, "PEC checking enabled.\n");
> +
> + fprintf(stderr, "Continue? [%s] ", dont ? "y/N" : "Y/n");
> + fflush(stderr);
> + if (!user_ack(!dont)) {
> + fprintf(stderr, "Aborting.\n");
> + xfunc_die();
> + }
> +}
> +
maybe this will work alsp ?
tolower(read_nonempty("Continue? Y/n"));
(see: util-linux/fdisk_osf.c)
> +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";
> +
> + unsigned opts;
> + int bus_num, bus_addr, data_addr = -1;
> + int mode = I2C_SMBUS_BYTE, pec = 0, fd, status;
> + char *end;
> + char filename[32];
> +
> + 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_addr(argv[1]);
> +
> + if (argc > 2) {
> + data_addr = bb_strtol(argv[2], &end, 16);
> + if (*end || data_addr < 0 || data_addr > 0xff)
> + err_msg_and_usage_and_die("Data address invalid");
> + }
> +
> + if (argc > 3) {
> + switch (argv[3][0]) {
> + case 'b': mode = I2C_SMBUS_BYTE_DATA; break;
> + case 'w': mode = I2C_SMBUS_WORD_DATA; break;
> + case 'c': /* Already set */ break;
> + default: err_msg_and_usage_and_die("Invalid mode");
> + }
> + pec = argv[3][1] == 'p';
> + }
> +
> + fd = i2c_dev_open(bus_num, filename, sizeof(filename));
> + check_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)
> + ioctl_or_perror_and_die(fd, I2C_PEC, INT_TO_PTR(1),
> + "Could not set PEC");
> +
> + 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_error_msg_and_die("Read failed");
> +
> + printf("0x%0*x\n", mode == I2C_SMBUS_WORD_DATA ? 4 : 2, status);
> +
> + return 0;
> +}
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