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

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>

diff --git a/common/cmd_i2c.c b/common/cmd_i2c.c
index 1bc0db860c3344dad85466fc52c0c61cddca3998..864b2596cca515d3e442a25a586fb79f56c33081 100644 (file)
--- a/common/cmd_i2c.c
+++ b/common/cmd_i2c.c
@@ -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)