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Message-ID: <20220721101528.118499-2-tmaimon77@gmail.com>
Date: Thu, 21 Jul 2022 13:15:27 +0300
From: Tomer Maimon <tmaimon77@...il.com>
To: <avifishman70@...il.com>, <tali.perry1@...il.com>,
<joel@....id.au>, <venture@...gle.com>, <yuenn@...gle.com>,
<benjaminfair@...gle.com>, <broonie@...nel.org>,
<robh+dt@...nel.org>, <krzysztof.kozlowski+dt@...aro.org>
CC: <openbmc@...ts.ozlabs.org>, <linux-spi@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
Tomer Maimon <tmaimon77@...il.com>
Subject: [PATCH v1 1/2] spi: npcm-pspi: add full duplex support
The NPCM PSPI handler, on TX-buffer not null, would perform a dummy read
but did not save the rx-data, this was valid only for half duplex.
This patch adds full duplex support for NPCM PSPI driver by storing all
rx-data when the Rx-buffer is defined also for TX-buffer handling.
Signed-off-by: Tomer Maimon <tmaimon77@...il.com>
---
drivers/spi/spi-npcm-pspi.c | 75 +++++++++++++++----------------------
1 file changed, 30 insertions(+), 45 deletions(-)
diff --git a/drivers/spi/spi-npcm-pspi.c b/drivers/spi/spi-npcm-pspi.c
index 1668a347e003..02f0fcceaf19 100644
--- a/drivers/spi/spi-npcm-pspi.c
+++ b/drivers/spi/spi-npcm-pspi.c
@@ -195,22 +195,22 @@ static void npcm_pspi_setup_transfer(struct spi_device *spi,
static void npcm_pspi_send(struct npcm_pspi *priv)
{
int wsize;
- u16 val;
+ u16 val = 0;
wsize = min(bytes_per_word(priv->bits_per_word), priv->tx_bytes);
priv->tx_bytes -= wsize;
- if (!priv->tx_buf)
- return;
-
switch (wsize) {
case 1:
- val = *priv->tx_buf++;
+ if (priv->tx_buf)
+ val = *priv->tx_buf++;
iowrite8(val, NPCM_PSPI_DATA + priv->base);
break;
case 2:
- val = *priv->tx_buf++;
- val = *priv->tx_buf++ | (val << 8);
+ if (priv->tx_buf) {
+ val = *priv->tx_buf++;
+ val = *priv->tx_buf++ | (val << 8);
+ }
iowrite16(val, NPCM_PSPI_DATA + priv->base);
break;
default:
@@ -222,22 +222,24 @@ static void npcm_pspi_send(struct npcm_pspi *priv)
static void npcm_pspi_recv(struct npcm_pspi *priv)
{
int rsize;
- u16 val;
+ u16 val_16;
+ u8 val_8;
rsize = min(bytes_per_word(priv->bits_per_word), priv->rx_bytes);
priv->rx_bytes -= rsize;
- if (!priv->rx_buf)
- return;
-
switch (rsize) {
case 1:
- *priv->rx_buf++ = ioread8(priv->base + NPCM_PSPI_DATA);
+ val_8 = ioread8(priv->base + NPCM_PSPI_DATA);
+ if (priv->rx_buf)
+ *priv->rx_buf++ = val_8;
break;
case 2:
- val = ioread16(priv->base + NPCM_PSPI_DATA);
- *priv->rx_buf++ = (val >> 8);
- *priv->rx_buf++ = val & 0xff;
+ val_16 = ioread16(priv->base + NPCM_PSPI_DATA);
+ if (priv->rx_buf) {
+ *priv->rx_buf++ = (val_16 >> 8);
+ *priv->rx_buf++ = val_16 & 0xff;
+ }
break;
default:
WARN_ON_ONCE(1);
@@ -296,43 +298,26 @@ static irqreturn_t npcm_pspi_handler(int irq, void *dev_id)
struct npcm_pspi *priv = dev_id;
u8 stat;
- stat = ioread8(priv->base + NPCM_PSPI_STAT);
-
if (!priv->tx_buf && !priv->rx_buf)
return IRQ_NONE;
- if (priv->tx_buf) {
- if (stat & NPCM_PSPI_STAT_RBF) {
- ioread8(NPCM_PSPI_DATA + priv->base);
- if (priv->tx_bytes == 0) {
- npcm_pspi_disable(priv);
- complete(&priv->xfer_done);
- return IRQ_HANDLED;
- }
- }
-
- if ((stat & NPCM_PSPI_STAT_BSY) == 0)
- if (priv->tx_bytes)
- npcm_pspi_send(priv);
+ if (priv->tx_bytes == 0 && priv->rx_bytes == 0) {
+ npcm_pspi_disable(priv);
+ complete(&priv->xfer_done);
+ return IRQ_HANDLED;
}
- if (priv->rx_buf) {
- if (stat & NPCM_PSPI_STAT_RBF) {
- if (!priv->rx_bytes)
- return IRQ_NONE;
-
- npcm_pspi_recv(priv);
+ stat = ioread8(priv->base + NPCM_PSPI_STAT);
- if (!priv->rx_bytes) {
- npcm_pspi_disable(priv);
- complete(&priv->xfer_done);
- return IRQ_HANDLED;
- }
- }
+ /*
+ * first we do the read since if we do the write we previous read might
+ * be lost (indeed low chances)
+ */
+ if ((stat & NPCM_PSPI_STAT_RBF) && priv->rx_bytes)
+ npcm_pspi_recv(priv);
- if (((stat & NPCM_PSPI_STAT_BSY) == 0) && !priv->tx_buf)
- iowrite8(0x0, NPCM_PSPI_DATA + priv->base);
- }
+ if (((stat & NPCM_PSPI_STAT_BSY) == 0) && priv->tx_bytes)
+ npcm_pspi_send(priv);
return IRQ_HANDLED;
}
--
2.33.0
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