[PATCH v7 09/14] spi/spi-atmel: correct 16 bits transfers using PIO

Wenyou Yang
2013-03-19T07:51:55Z

From: Richard Genoud <richard.genoud@gmail.com>

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Cc: spi-devel-general@lists.sourceforge.net
Cc: linux-kernel@vger.kernel.org
[wenyou.yang@atmel.com: submit the patch]
Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
---
drivers/spi/spi-atmel.c | 47 ++++++++++++++++++++++++++++++++++++++---------
1 file changed, 38 insertions(+), 9 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index d724c03..3aa3809 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -520,13 +520,17 @@ static void atmel_spi_next_xfer_pio(struct spi_master *master,
}

if (xfer->tx_buf)
- spi_writel(as, TDR, *(u8 *)(xfer->tx_buf));
+ if (xfer->bits_per_word > 8)
+ spi_writel(as, TDR, *(u16 *)(xfer->tx_buf));
+ else
+ spi_writel(as, TDR, *(u8 *)(xfer->tx_buf));
else
spi_writel(as, TDR, 0);

dev_dbg(master->dev.parent,
- " start pio xfer %p: len %u tx %p rx %p\n",
- xfer, xfer->len, xfer->tx_buf, xfer->rx_buf);
+ " start pio xfer %p: len %u tx %p rx %p bitpw %d\n",
+ xfer, xfer->len, xfer->tx_buf, xfer->rx_buf,
+ xfer->bits_per_word);

/* Enable relevant interrupts */
spi_writel(as, IER, SPI_BIT(RDRF) | SPI_BIT(OVRES));
@@ -945,21 +949,39 @@ atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer)
{
u8 *txp;
u8 *rxp;
+ u16 *txp16;
+ u16 *rxp16;
unsigned long xfer_pos = xfer->len - as->current_remaining_bytes;

if (xfer->rx_buf) {
- rxp = ((u8 *)xfer->rx_buf) + xfer_pos;
- *rxp = spi_readl(as, RDR);
+ if (xfer->bits_per_word > 8) {
+ rxp16 = (u16 *)(((u8 *)xfer->rx_buf) + xfer_pos);
+ *rxp16 = spi_readl(as, RDR);
+ } else {
+ rxp = ((u8 *)xfer->rx_buf) + xfer_pos;
+ *rxp = spi_readl(as, RDR);
+ }
} else {
spi_readl(as, RDR);
}
-
- as->current_remaining_bytes--;
+ if (xfer->bits_per_word > 8) {
+ as->current_remaining_bytes -= 2;
+ if (as->current_remaining_bytes < 0)
+ as->current_remaining_bytes = 0;
+ } else {
+ as->current_remaining_bytes--;
+ }

if (as->current_remaining_bytes) {
if (xfer->tx_buf) {
- txp = ((u8 *)xfer->tx_buf) + xfer_pos + 1;
- spi_writel(as, TDR, *txp);
+ if (xfer->bits_per_word > 8) {
+ txp16 = (u16 *)(((u8 *)xfer->tx_buf)
+ + xfer_pos + 2);
+ spi_writel(as, TDR, *txp16);
+ } else {
+ txp = ((u8 *)xfer->tx_buf) + xfer_pos + 1;
+ spi_writel(as, TDR, *txp);
+ }
} else {
spi_writel(as, TDR, 0);
}
@@ -1373,6 +1395,13 @@ static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg)
}
}

+ if (xfer->bits_per_word > 8) {
+ if (xfer->len % 2) {
+ dev_dbg(&spi->dev, "buffer len should be 16 bits aligned\n");
+ return -EINVAL;
+ }
+ }
+
/* FIXME implement these protocol options!! */
if (xfer->speed_hz < spi->max_speed_hz) {
dev_dbg(&spi->dev, "can't change speed in transfer\n");
--
1.7.9.5