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DW SPI: refactor poll_transfer functions

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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.Paltsev@synopsys.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>
This commit is contained in:
Eugeniy Paltsev 2018-03-22 13:50:45 +03:00 • committed by Jagan Teki
parent fc282c7bcb
commit d3d8aaec74
1 changed files with 4 additions and 22 deletions
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26
drivers/spi/designware_spi.c
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@ -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 = rx_max(priv);
u32 max;
u16 rxw; 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--) { while (max--) {
rxw = dw_readw(priv, DW_SPI_DR); rxw = dw_readw(priv, DW_SPI_DR);
debug("%s: rx=0x%02x\n", __func__, rxw); debug("%s: rx=0x%02x\n", __func__, rxw);
/* /* Care about rx if the transfer's original "rx" is not null */
* Care about rx only if the transfer's original "rx" is
* not null
*/
if (priv->rx_end - priv->len) { if (priv->rx_end - priv->len) {
if (priv->bits_per_word == 8) if (priv->bits_per_word == 8)
*(u8 *)(priv->rx) = rxw; *(u8 *)(priv->rx) = rxw;
@ -316,19 +304,13 @@ static int dw_reader(struct dw_spi_priv *priv)
} }
priv->rx += priv->bits_per_word >> 3; priv->rx += priv->bits_per_word >> 3;
} }
return 0;
} }
static int poll_transfer(struct dw_spi_priv *priv) static int poll_transfer(struct dw_spi_priv *priv)
{ {
int ret;
do { do {
dw_writer(priv); dw_writer(priv);
ret = dw_reader(priv); dw_reader(priv);
if (ret < 0)
return ret;
} while (priv->rx_end > priv->rx); } while (priv->rx_end > priv->rx);
return 0; return 0;