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author | mario.six@gdsys.cc <mario.six@gdsys.cc> | 2016-04-25 08:31:03 +0200 |
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committer | Heiko Schocher <hs@denx.de> | 2016-05-17 08:28:52 +0200 |
commit | 386b276918541f4108b56f0c7c422b64396f64f2 (patch) | |
tree | 441bdb56b767ace02cd130444a5032e5ad092f25 /drivers/i2c/fsl_i2c.c | |
parent | 2b21e960348998fbaefc802613c37bfb6321969b (diff) | |
download | u-boot-386b276918541f4108b56f0c7c422b64396f64f2.tar.gz |
dm: fsl_i2c: Reword and clarify comment
Signed-off-by: Mario Six <mario.six@gdsys.cc>
Diffstat (limited to 'drivers/i2c/fsl_i2c.c')
-rw-r--r-- | drivers/i2c/fsl_i2c.c | 20 |
1 files changed, 6 insertions, 14 deletions
diff --git a/drivers/i2c/fsl_i2c.c b/drivers/i2c/fsl_i2c.c index b0e65fcf65..18b8848ced 100644 --- a/drivers/i2c/fsl_i2c.c +++ b/drivers/i2c/fsl_i2c.c @@ -428,22 +428,14 @@ fsl_i2c_read(struct i2c_adapter *adap, u8 chip_addr, uint offset, int olen, if (i2c_wait4bus(adap) < 0) return -1; - /* To handle the need of I2C devices that require to write few bytes - * (more than 4 bytes of address as in the case of else part) - * of data before reading, Negative equivalent of dlen(bytes to write) - * is passed, but used the +ve part of len for writing data + /* Some drivers use offset lengths in excess of 4 bytes. These drivers + * adhere to the following convention: + * - the offset length is passed as negative (that is, the absolute + * value of olen is the actual offset length) + * - the offset itself is passed in data, which is overwritten by the + * subsequent read operation */ if (olen < 0) { - /* Generate a START and send the Address and - * the Tx Bytes to the slave. - * "START: Address: Write bytes data[len]" - * IF part supports writing any number of bytes in contrast - * to the else part, which supports writing address offset - * of upto 4 bytes only. - * bytes that need to be written are passed in - * "data", which will eventually keep the data READ, - * after writing the len bytes out of it - */ if (i2c_write_addr(adap, chip_addr, I2C_WRITE_BIT, 0) != 0) ret = __i2c_write(adap, data, len); |