greybus: add write retry support for i2c

It is expected that i2c writes may fail, and in that case the driver
simply retries some number of times before actually treating it as a
failure.  Define a GB_OP_RETRY status, which is interpreted by the
i2c driver as an indication a retry is in order.  We just translate
that into an EAGAIN error passed back to the i2c core.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

diff --git a/drivers/staging/greybus/i2c-gb.c b/drivers/staging/greybus/i2c-gb.c
index c4e47effa9f54010b49475944131f6c66e0a6cf8..e1a0ed9dc6f2f1c7a919ee7c27e6d92be6e82f2e 100644 (file)
--- a/drivers/staging/greybus/i2c-gb.c
+++ b/drivers/staging/greybus/i2c-gb.c
@@ -382,9 +382,13 @@ static int gb_i2c_transfer_operation(struct gb_i2c_device *gb_i2c_dev,
 
        response = operation->response_payload;
        if (response->status) {
-               gb_connection_err(connection, "transfer response %hhu",
-                       response->status);
-               ret = -EIO;
+               if (response->status == GB_OP_RETRY) {
+                       ret = -EAGAIN;
+               } else {
+                       gb_connection_err(connection, "transfer response %hhu",
+                               response->status);
+                       ret = -EIO;
+               }
        } else {
                gb_i2c_transfer_response(msgs, msg_count, response->data);
                ret = msg_count;

diff --git a/drivers/staging/greybus/operation.h b/drivers/staging/greybus/operation.h
index d5ec582e21a2b2a44a627c6c92c91d68b589576e..59aad3a38d17951b38c231d96c3296128655c808 100644 (file)
--- a/drivers/staging/greybus/operation.h
+++ b/drivers/staging/greybus/operation.h
@@ -16,7 +16,8 @@ enum gb_operation_status {
        GB_OP_INVALID           = 1,
        GB_OP_NO_MEMORY         = 2,
        GB_OP_INTERRUPTED       = 3,
-       GB_OP_PROTOCOL_BAD      = 4,
+       GB_OP_RETRY             = 4,
+       GB_OP_PROTOCOL_BAD      = 5,
 };
 
 /*