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Message-ID: <1596610933-32599-18-git-send-email-alain.volmat@st.com>
Date: Wed, 5 Aug 2020 09:02:12 +0200
From: Alain Volmat <alain.volmat@...com>
To: <broonie@...nel.org>, <amelie.delaunay@...com>
CC: <mcoquelin.stm32@...il.com>, <alexandre.torgue@...com>,
<linux-spi@...r.kernel.org>,
<linux-stm32@...md-mailman.stormreply.com>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <fabrice.gasnier@...com>,
<alain.volmat@...com>
Subject: [PATCH 17/18] spi: stm32: properly handle 0 byte transfer
On 0 byte transfer request, return straight from the
xfer function after finalizing the transfer.
Signed-off-by: Alain Volmat <alain.volmat@...com>
---
drivers/spi/spi-stm32.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index 177f82700de0..b909afd9e99b 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -1658,6 +1658,12 @@ static int stm32_spi_transfer_one(struct spi_master *master,
unsigned long timeout;
int ret;
+ /* Don't do anything on 0 bytes transfers */
+ if (transfer->len == 0) {
+ spi->xfer_status = 0;
+ goto finalize;
+ }
+
spi->tx_buf = transfer->tx_buf;
spi->rx_buf = transfer->rx_buf;
spi->tx_len = spi->tx_buf ? transfer->len : 0;
@@ -1702,6 +1708,7 @@ static int stm32_spi_transfer_one(struct spi_master *master,
spi->cfg->disable(spi);
+finalize:
spi_finalize_current_transfer(master);
return spi->xfer_status;
--
2.7.4
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