Signed-off-by: Mario Six <mario....@gdsys.cc>
---
drivers/i2c/fsl_i2c.c | 20 ++++++--------------
1 file changed, 6 insertions(+), 14 deletions(-)
diff --git a/drivers/i2c/fsl_i2c.c b/drivers/i2c/fsl_i2c.c
index b0e65fc..18b8848 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);
--
2.7.0.GIT
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