There is no sense in waiting for RX data in dw_reader function:
there is no chance that RX data will appear in RX FIFO if
RX FIFO is empty after previous TX write in dw_writer function.
So get rid of this waiting. After that we can get rid of dw_reader
return value and make it returning void. After that we can get rid
of dw_reader return value check in poll_transfer function.
With these changes we're getting closer to Linux DW SPI driver.
Signed-off-by: Eugeniy Paltsev <eugeniy.palt...@synopsys.com>
---
Changes v1->v2:
* None.
drivers/spi/designware_spi.c | 26 ++++----------------------
1 file changed, 4 insertions(+), 22 deletions(-)
diff --git a/drivers/spi/designware_spi.c b/drivers/spi/designware_spi.c
index 3296441606..b51242c862 100644
--- a/drivers/spi/designware_spi.c
+++ b/drivers/spi/designware_spi.c
@@ -286,28 +286,16 @@ static void dw_writer(struct dw_spi_priv *priv)
}
}
-static int dw_reader(struct dw_spi_priv *priv)
+static void dw_reader(struct dw_spi_priv *priv)
{
- unsigned start = get_timer(0);
- u32 max;
+ u32 max = rx_max(priv);
u16 rxw;
- /* Wait for rx data to be ready */
- while (rx_max(priv) == 0) {
- if (get_timer(start) > RX_TIMEOUT)
- return -ETIMEDOUT;
- }
-
- max = rx_max(priv);
-
while (max--) {
rxw = dw_readw(priv, DW_SPI_DR);
debug("%s: rx=0x%02x\n", __func__, rxw);
- /*
- * Care about rx only if the transfer's original "rx" is
- * not null
- */
+ /* Care about rx if the transfer's original "rx" is not null */
if (priv->rx_end - priv->len) {
if (priv->bits_per_word == 8)
*(u8 *)(priv->rx) = rxw;
@@ -316,19 +304,13 @@ static int dw_reader(struct dw_spi_priv *priv)
}
priv->rx += priv->bits_per_word >> 3;
}
-
- return 0;
}
static int poll_transfer(struct dw_spi_priv *priv)
{
- int ret;
-
do {
dw_writer(priv);
- ret = dw_reader(priv);
- if (ret < 0)
- return ret;
+ dw_reader(priv);
} while (priv->rx_end > priv->rx);
return 0;
--
2.14.3
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