i2c: Don't check return value from i2c_recv()

i2c_recv() cannot fail, so there is no need to check the return
value.  It also returns unt8_t, so comparing with < 0 is not
meaningful.

Fix up various I2C controllers to remove the unneeded code.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Suggested-by: Peter Maydell <peter.maydell@linaro.org>

hw/i2c/aspeed_i2c.c

@@ -189,16 +189,11 @@ static uint8_t aspeed_i2c_get_state(AspeedI2CBus *bus)
 
 static void aspeed_i2c_handle_rx_cmd(AspeedI2CBus *bus)
 {
-    int ret;
+    uint8_t ret;
 
     aspeed_i2c_set_state(bus, I2CD_MRXD);
     ret = i2c_recv(bus->bus);
-    if (ret < 0) {
-        qemu_log_mask(LOG_GUEST_ERROR, "%s: read failed\n", __func__);
-        ret = 0xff;
-    } else {
-        bus->intr_status |= I2CD_INTR_RX_DONE;
-    }
+    bus->intr_status |= I2CD_INTR_RX_DONE;
     bus->buf = (ret & I2CD_BYTE_BUF_RX_MASK) << I2CD_BYTE_BUF_RX_SHIFT;
     if (bus->cmd & I2CD_M_S_RX_CMD_LAST) {
         i2c_nack(bus->bus);

hw/i2c/exynos4210_i2c.c

@@ -106,16 +106,10 @@ static inline void exynos4210_i2c_raise_interrupt(Exynos4210I2CState *s)
 static void exynos4210_i2c_data_receive(void *opaque)
 {
     Exynos4210I2CState *s = (Exynos4210I2CState *)opaque;
-    int ret;
 
     s->i2cstat &= ~I2CSTAT_LAST_BIT;
     s->scl_free = false;
-    ret = i2c_recv(s->bus);
-    if (ret < 0 && (s->i2ccon & I2CCON_ACK_GEN)) {
-        s->i2cstat |= I2CSTAT_LAST_BIT;  /* Data is not acknowledged */
-    } else {
-        s->i2cds = ret;
-    }
+    s->i2cds = i2c_recv(s->bus);
     exynos4210_i2c_raise_interrupt(s);
 }
 

hw/i2c/imx_i2c.c

@@ -120,7 +120,7 @@ static uint64_t imx_i2c_read(void *opaque, hwaddr offset,
         value = s->i2dr_read;
 
         if (imx_i2c_is_master(s)) {
-            int ret = 0xff;
+            uint8_t ret = 0xff;
 
             if (s->address == ADDR_RESET) {
                 /* something is wrong as the address is not set */
@@ -133,15 +133,7 @@ static uint64_t imx_i2c_read(void *opaque, hwaddr offset,
             } else {
                 /* get the next byte */
                 ret = i2c_recv(s->bus);
-
-                if (ret >= 0) {
-                    imx_i2c_raise_interrupt(s);
-                } else {
-                    qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: read failed "
-                                  "for device 0x%02x\n", TYPE_IMX_I2C,
-                                  __func__, s->address);
-                    ret = 0xff;
-                }
+                imx_i2c_raise_interrupt(s);
             }
 
             s->i2dr_read = ret;