[Qemu-devel] [RFC v1 1/1] i2c: Factor our send() and recv() common logic

[Peter Crosthwaite]

Most of the control flow logic between send and recv (error checking
etc) is the same. Factor this out into a common send_recv() API.
This is then usable by clients, where the control logic for send 
and receive differs only by a boolean. E.g.

if (send)
   i2c_send(...):
else
   i2c_recv(...);

becomes:

i2c_send_recv(... , send);

Signed-off-by: Peter Crosthwaite <crosthwaite.pe...@gmail.com>
---

 hw/i2c/core.c        | 34 +++++++++++++++++++---------------
 include/hw/i2c/i2c.h |  1 +
 2 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/hw/i2c/core.c b/hw/i2c/core.c
index 5a64026..d4a8cbb 100644
--- a/hw/i2c/core.c
+++ b/hw/i2c/core.c
@@ -129,7 +129,7 @@ void i2c_end_transfer(I2CBus *bus)
     bus->current_dev = NULL;
 }
 
-int i2c_send(I2CBus *bus, uint8_t data)
+int i2c_send_recv(I2CBus  *bus, uint8_t *data, bool send)
 {
     I2CSlave *dev = bus->current_dev;
     I2CSlaveClass *sc;
@@ -139,28 +139,32 @@ int i2c_send(I2CBus *bus, uint8_t data)
     }
 
     sc = I2C_SLAVE_GET_CLASS(dev);
-    if (sc->send) {
-        return sc->send(dev, data);
+    if (send && sc->send) {
+        return sc->send(dev, *data);
+    } else if (!send && sc->recv) {
+        int ret = sc->recv(dev);
+        if (ret < 0) {
+            return ret;
+        } else {
+            *data = ret;
+            return 0;
+        }
     }
 
     return -1;
 }
 
-int i2c_recv(I2CBus *bus)
+int i2c_send(I2CBus *bus, uint8_t data)
 {
-    I2CSlave *dev = bus->current_dev;
-    I2CSlaveClass *sc;
-
-    if (!dev) {
-        return -1;
-    }
+    return i2c_send_recv(bus, &data, true);
+}
 
-    sc = I2C_SLAVE_GET_CLASS(dev);
-    if (sc->recv) {
-        return sc->recv(dev);
-    }
+int i2c_recv(I2CBus *bus)
+{
+    uint8_t data;
+    int ret = i2c_send_recv(bus, &data, false);
 
-    return -1;
+    return ret < 0 ? ret : data;
 }
 
 void i2c_nack(I2CBus *bus)
diff --git a/include/hw/i2c/i2c.h b/include/hw/i2c/i2c.h
index 4986ebc..c4085aa 100644
--- a/include/hw/i2c/i2c.h
+++ b/include/hw/i2c/i2c.h
@@ -56,6 +56,7 @@ int i2c_bus_busy(I2CBus *bus);
 int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv);
 void i2c_end_transfer(I2CBus *bus);
 void i2c_nack(I2CBus *bus);
+int i2c_send_recv(I2CBus *bus, uint8_t *data, bool send);
 int i2c_send(I2CBus *bus, uint8_t data);
 int i2c_recv(I2CBus *bus);
 
-- 
1.9.1