i2c: mv64xxx: separated transaction segments by repeated STARTs.
All transaction segments (all i2c_msg's passed to a single call to master_xfer)
should be separated on the bus by repeated START conditions. This change makes
that so with the exception of zero-byte reads (which don't make sense since the
slave will assume control of the data line). Zero-byte reads early terminate the
transaction.
Change-Id: I5ed9cbd94b6df0dc0bd33a7b8c0078e396fecd24
diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index bbab0e1..e993488 100644
--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@@ -75,6 +75,8 @@
MV64XXX_I2C_ACTION_SEND_DATA,
MV64XXX_I2C_ACTION_RCV_DATA,
MV64XXX_I2C_ACTION_RCV_DATA_STOP,
+ MV64XXX_I2C_ACTION_RESTART,
+ MV64XXX_I2C_ACTION_RCV_DATA_RESTART,
MV64XXX_I2C_ACTION_SEND_STOP,
};
@@ -98,6 +100,7 @@
wait_queue_head_t waitq;
spinlock_t lock;
struct i2c_msg *msg;
+ int msgs_left; /* not counting msg */
struct i2c_adapter adapter;
};
@@ -156,11 +159,16 @@
/* FALLTHRU */
case MV64XXX_I2C_STATUS_MAST_WR_ADDR_2_ACK: /* 0xd0 */
case MV64XXX_I2C_STATUS_MAST_WR_ACK: /* 0x28 */
- if ((drv_data->bytes_left == 0)
+ if (((drv_data->bytes_left == 0) && (drv_data->msgs_left == 0))
|| (drv_data->aborting
&& (drv_data->byte_posn != 0))) {
drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
drv_data->state = MV64XXX_I2C_STATE_IDLE;
+ } else if ((drv_data->bytes_left == 0)
+ && (drv_data->msgs_left > 0) ) {
+ drv_data->action = MV64XXX_I2C_ACTION_RESTART;
+ drv_data->state =
+ MV64XXX_I2C_STATE_WAITING_FOR_START_COND;
} else {
drv_data->action = MV64XXX_I2C_ACTION_SEND_DATA;
drv_data->state =
@@ -199,8 +207,14 @@
break;
case MV64XXX_I2C_STATUS_MAST_RD_DATA_NO_ACK: /* 0x58 */
- drv_data->action = MV64XXX_I2C_ACTION_RCV_DATA_STOP;
- drv_data->state = MV64XXX_I2C_STATE_IDLE;
+ if (drv_data->msgs_left == 0) {
+ drv_data->action = MV64XXX_I2C_ACTION_RCV_DATA_STOP;
+ drv_data->state = MV64XXX_I2C_STATE_IDLE;
+ } else {
+ drv_data->action = MV64XXX_I2C_ACTION_RCV_DATA_RESTART;
+ drv_data->state =
+ MV64XXX_I2C_STATE_WAITING_FOR_START_COND;
+ }
break;
case MV64XXX_I2C_STATUS_MAST_WR_ADDR_NO_ACK: /* 0x20 */
@@ -224,6 +238,9 @@
}
}
+static void mv64xxx_i2c_prepare_for_io(struct mv64xxx_i2c_data *drv_data,
+ struct i2c_msg *msg);
+
static void
mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
{
@@ -276,6 +293,17 @@
wake_up_interruptible(&drv_data->waitq);
break;
+ case MV64XXX_I2C_ACTION_RCV_DATA_RESTART:
+ drv_data->msg->buf[drv_data->byte_posn++] =
+ readl(drv_data->reg_base + MV64XXX_I2C_REG_DATA);
+ /* FALLTHRU */
+ case MV64XXX_I2C_ACTION_RESTART:
+ writel(drv_data->cntl_bits | MV64XXX_I2C_REG_CONTROL_START,
+ drv_data->reg_base + MV64XXX_I2C_REG_CONTROL);
+ drv_data->msgs_left--;
+ mv64xxx_i2c_prepare_for_io(drv_data, drv_data->msg + 1);
+ break;
+
case MV64XXX_I2C_ACTION_INVALID:
default:
dev_err(&drv_data->adapter.dev,
@@ -389,8 +417,10 @@
}
static int
-mv64xxx_i2c_execute_msg(struct mv64xxx_i2c_data *drv_data, struct i2c_msg *msg)
+mv64xxx_i2c_execute_msgs(struct mv64xxx_i2c_data *drv_data,
+ struct i2c_msg *msgs, int nr_msgs)
{
+ struct i2c_msg *msg = &msgs[0];
unsigned long flags;
spin_lock_irqsave(&drv_data->lock, flags);
@@ -414,6 +444,7 @@
}
drv_data->block = 1;
+ drv_data->msgs_left = nr_msgs - 1;
mv64xxx_i2c_do_action(drv_data);
spin_unlock_irqrestore(&drv_data->lock, flags);
@@ -438,13 +469,13 @@
mv64xxx_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
struct mv64xxx_i2c_data *drv_data = i2c_get_adapdata(adap);
- int i, rc;
+ int rc;
- for (i=0; i<num; i++)
- if ((rc = mv64xxx_i2c_execute_msg(drv_data, &msgs[i])) < 0)
- return rc;
+ rc = mv64xxx_i2c_execute_msgs(drv_data, msgs, num);
+ if (rc < 0)
+ return rc;
- return num;
+ return num - drv_data->msgs_left;
}
static const struct i2c_algorithm mv64xxx_i2c_algo = {
