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dm: i2c: Add a command to adjust the offset length

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I2C chips can support a register offset, with registers accessible by
sending this offset as the first part of any read or write transaction.
Most I2C chips have a single byte offset, thus the offset length is 1.
This provides access for up 256 registers.

However other offset lengths are supported, including 0.

Add a command to provide access to the offset length from the command
line. This allows the offset length to be read or written.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Christophe Ricard<christophe-h.ricard@st.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
This commit is contained in:
Simon Glass 2015-08-22 18:31:33 -06:00
parent c8a8c51039
commit c10c8e313c
1 changed files with 33 additions and 0 deletions
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33
common/cmd_i2c.c
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@ -453,6 +453,37 @@ static int do_i2c_flags(cmd_tbl_t *cmdtp, int flag, int argc,
return 0;
}
static int do_i2c_olen(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
{
struct udevice *dev;
uint olen;
int chip;
int ret;
if (argc < 2)
return CMD_RET_USAGE;
chip = simple_strtoul(argv[1], NULL, 16);
ret = i2c_get_cur_bus_chip(chip, &dev);
if (ret)
return i2c_report_err(ret, I2C_ERR_READ);
if (argc > 2) {
olen = simple_strtoul(argv[2], NULL, 16);
ret = i2c_set_chip_offset_len(dev, olen);
} else {
ret = i2c_get_chip_offset_len(dev);
if (ret >= 0) {
printf("%x\n", ret);
ret = 0;
}
}
if (ret)
return i2c_report_err(ret, I2C_ERR_READ);
return 0;
}
#endif
/**
@ -1903,6 +1934,7 @@ static cmd_tbl_t cmd_i2c_sub[] = {
U_BOOT_CMD_MKENT(write, 6, 0, do_i2c_write, "", ""),
#ifdef CONFIG_DM_I2C
U_BOOT_CMD_MKENT(flags, 2, 1, do_i2c_flags, "", ""),
U_BOOT_CMD_MKENT(olen, 2, 1, do_i2c_olen, "", ""),
#endif
U_BOOT_CMD_MKENT(reset, 0, 1, do_i2c_reset, "", ""),
#if defined(CONFIG_CMD_SDRAM)
@ -1971,6 +2003,7 @@ static char i2c_help_text[] =
" to I2C; the -s option selects bulk write in a single transaction\n"
#ifdef CONFIG_DM_I2C
"i2c flags chip [flags] - set or get chip flags\n"
"i2c olen chip [offset_length] - set or get chip offset length\n"
#endif
"i2c reset - re-init the I2C Controller\n"
#if defined(CONFIG_CMD_SDRAM)