i2c: rcar: reset controller is mandatory for Gen3+

Initially, we only needed a reset controller to make sure RXDMA works at
least once per transfer. Meanwhile, documentation has been updated. It
now says that a reset has to be performed prior every transaction, even
if it is non-DMA. So, make the reset controller a requirement instead of
being optional. And bail out if resetting fails.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 5e97635faf785d1e6aa43a14fa9a10667981706b..6800059514bcb969fc5109bad66aa1625e7f8b5a 100644 (file)
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -838,12 +838,10 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
 
        /* Gen3 needs a reset before allowing RXDMA once */
        if (priv->devtype == I2C_RCAR_GEN3) {
-               priv->flags |= ID_P_NO_RXDMA;
-               if (!IS_ERR(priv->rstc)) {
-                       ret = rcar_i2c_do_reset(priv);
-                       if (ret == 0)
-                               priv->flags &= ~ID_P_NO_RXDMA;
-               }
+               priv->flags &= ~ID_P_NO_RXDMA;
+               ret = rcar_i2c_do_reset(priv);
+               if (ret)
+                       goto out;
        }
 
        rcar_i2c_init(priv);
@@ -1094,15 +1092,6 @@ static int rcar_i2c_probe(struct platform_device *pdev)
                irqhandler = rcar_i2c_gen2_irq;
        }
 
-       if (priv->devtype == I2C_RCAR_GEN3) {
-               priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
-               if (!IS_ERR(priv->rstc)) {
-                       ret = reset_control_status(priv->rstc);
-                       if (ret < 0)
-                               priv->rstc = ERR_PTR(-ENOTSUPP);
-               }
-       }
-
        /* Stay always active when multi-master to keep arbitration working */
        if (of_property_read_bool(dev->of_node, "multi-master"))
                priv->flags |= ID_P_PM_BLOCKED;
@@ -1112,6 +1101,16 @@ static int rcar_i2c_probe(struct platform_device *pdev)
        if (of_property_read_bool(dev->of_node, "smbus"))
                priv->flags |= ID_P_HOST_NOTIFY;
 
+       if (priv->devtype == I2C_RCAR_GEN3) {
+               priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+               if (IS_ERR(priv->rstc))
+                       goto out_pm_put;
+
+               ret = reset_control_status(priv->rstc);
+               if (ret < 0)
+                       goto out_pm_put;
+       }
+
        ret = platform_get_irq(pdev, 0);
        if (ret < 0)
                goto out_pm_put;