i2c: tegra-bpmp: Implement better error handling

Inspect a message's return value upon successful IVC transaction to
determine if the I2C transaction on the BPMP side was successful.

Heavily based on work by Timo Alho <talho@nvidia.com>.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

diff --git a/drivers/i2c/busses/i2c-tegra-bpmp.c b/drivers/i2c/busses/i2c-tegra-bpmp.c
index c0c7d01473f2ba110553c0349e10ca6b03dbb7ca..c934d636f625414ae25b2e43fc73c687dfdd7781 100644 (file)
--- a/drivers/i2c/busses/i2c-tegra-bpmp.c
+++ b/drivers/i2c/busses/i2c-tegra-bpmp.c
@@ -217,7 +217,32 @@ static int tegra_bpmp_i2c_msg_xfer(struct tegra_bpmp_i2c *i2c,
        else
                err = tegra_bpmp_transfer(i2c->bpmp, &msg);
 
-       return err;
+       if (err < 0) {
+               dev_err(i2c->dev, "failed to transfer message: %d\n", err);
+               return err;
+       }
+
+       if (msg.rx.ret != 0) {
+               if (msg.rx.ret == -BPMP_EAGAIN) {
+                       dev_dbg(i2c->dev, "arbitration lost\n");
+                       return -EAGAIN;
+               }
+
+               if (msg.rx.ret == -BPMP_ETIMEDOUT) {
+                       dev_dbg(i2c->dev, "timeout\n");
+                       return -ETIMEDOUT;
+               }
+
+               if (msg.rx.ret == -BPMP_ENXIO) {
+                       dev_dbg(i2c->dev, "NAK\n");
+                       return -ENXIO;
+               }
+
+               dev_err(i2c->dev, "transaction failed: %d\n", msg.rx.ret);
+               return -EIO;
+       }
+
+       return 0;
 }
 
 static int tegra_bpmp_i2c_xfer_common(struct i2c_adapter *adapter,