[PATCH v6 21/35] i2c: tegra: Don't fall back to PIO mode if DMA configuration fails

[Dmitry Osipenko]

The DMA code path has been tested well enough and the DMA configuration
performed by tegra_i2c_config_fifo_trig() shouldn't ever fail in practice.
Hence let's remove the obscure transfer-mode switching in order to have a
cleaner and simpler code. Now I2C transfer will be failed if DMA
configuration fails.

Signed-off-by: Dmitry Osipenko <dig...@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index e94da14d36e2..ba71b64e5e64 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -940,8 +940,7 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
        return IRQ_HANDLED;
 }
 
-static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev,
-                                      size_t len)
+static int tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev, size_t 
len)
 {
        u32 val, reg;
        u8 dma_burst;
@@ -992,12 +991,10 @@ static void tegra_i2c_config_fifo_trig(struct 
tegra_i2c_dev *i2c_dev,
                if (ret < 0) {
                        dev_err(i2c_dev->dev, "DMA slave config failed: %d\n",
                                ret);
-                       dev_err(i2c_dev->dev, "falling back to PIO\n");
-                       tegra_i2c_release_dma(i2c_dev);
-                       i2c_dev->is_curr_dma_xfer = false;
-               } else {
-                       goto out;
+                       return ret;
                }
+
+               goto out;
        }
 
        if (i2c_dev->hw->has_mst_fifo)
@@ -1008,6 +1005,8 @@ static void tegra_i2c_config_fifo_trig(struct 
tegra_i2c_dev *i2c_dev,
                      I2C_FIFO_CONTROL_RX_TRIG(1);
 out:
        i2c_writel(i2c_dev, val, reg);
+
+       return 0;
 }
 
 static unsigned long
@@ -1141,7 +1140,10 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev 
*i2c_dev,
        i2c_dev->is_curr_dma_xfer = (xfer_size > I2C_PIO_MODE_PREFERRED_LEN) &&
                                    i2c_dev->dma_buf &&
                                    !i2c_dev->is_curr_atomic_xfer;
-       tegra_i2c_config_fifo_trig(i2c_dev, xfer_size);
+
+       err = tegra_i2c_config_fifo_trig(i2c_dev, xfer_size);
+       if (err)
+               return err;
 
        /*
         * Transfer time in mSec = Total bits / transfer rate
-- 
2.27.0