[PATCH 5.15 344/917] spi: Fixed division by zero warning

Greg Kroah-Hartman
2021-11-16T00:56:16Z

From: Yoshitaka Ikeda <ikeda@nskint.co.jp>

[ Upstream commit 09134c5322df9f105d9ed324051872d5d0e162aa ]

The reason for dividing by zero is because the dummy bus width is zero,
but if the dummy n bytes is zero, it indicates that there is no data transfer,
so there is no need for calculation.

Fixes: 7512eaf54190 ("spi: cadence-quadspi: Fix dummy cycle calculation when buswidth > 1")
Signed-off-by: Yoshitaka Ikeda <ikeda@nskint.co.jp>
Acked-by: Pratyush Yadav <p.yadav@ti.com>
Link: https://lore.kernel.org/r/OSZPR01MB70049C8F56ED8902852DF97B8BD49@OSZPR01MB7004.jpnprd01.prod.outlook.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/spi/atmel-quadspi.c | 2 +-
drivers/spi/spi-bcm-qspi.c | 3 ++-
drivers/spi/spi-mtk-nor.c | 2 +-
drivers/spi/spi-stm32-qspi.c | 2 +-
4 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/atmel-quadspi.c b/drivers/spi/atmel-quadspi.c
index 95d4fa32c2995..92d9610df1fd8 100644
--- a/drivers/spi/atmel-quadspi.c
+++ b/drivers/spi/atmel-quadspi.c
@@ -310,7 +310,7 @@ static int atmel_qspi_set_cfg(struct atmel_qspi *aq,
return mode;
ifr |= atmel_qspi_modes[mode].config;

- if (op->dummy.buswidth && op->dummy.nbytes)
+ if (op->dummy.nbytes)
dummy_cycles = op->dummy.nbytes * 8 / op->dummy.buswidth;

/*
diff --git a/drivers/spi/spi-bcm-qspi.c b/drivers/spi/spi-bcm-qspi.c
index ea1865c08fc22..151e154284bde 100644
--- a/drivers/spi/spi-bcm-qspi.c
+++ b/drivers/spi/spi-bcm-qspi.c
@@ -395,7 +395,8 @@ static int bcm_qspi_bspi_set_flex_mode(struct bcm_qspi *qspi,
if (addrlen == BSPI_ADDRLEN_4BYTES)
bpp = BSPI_BPP_ADDR_SELECT_MASK;

- bpp |= (op->dummy.nbytes * 8) / op->dummy.buswidth;
+ if (op->dummy.nbytes)
+ bpp |= (op->dummy.nbytes * 8) / op->dummy.buswidth;

switch (width) {
case SPI_NBITS_SINGLE:
diff --git a/drivers/spi/spi-mtk-nor.c b/drivers/spi/spi-mtk-nor.c
index 41e7b341d2616..5c93730615f8d 100644
--- a/drivers/spi/spi-mtk-nor.c
+++ b/drivers/spi/spi-mtk-nor.c
@@ -160,7 +160,7 @@ static bool mtk_nor_match_read(const struct spi_mem_op *op)
{
int dummy = 0;

- if (op->dummy.buswidth)
+ if (op->dummy.nbytes)
dummy = op->dummy.nbytes * BITS_PER_BYTE / op->dummy.buswidth;

if ((op->data.buswidth == 2) || (op->data.buswidth == 4)) {
diff --git a/drivers/spi/spi-stm32-qspi.c b/drivers/spi/spi-stm32-qspi.c
index 27f35aa2d746d..514337c86d2c3 100644
--- a/drivers/spi/spi-stm32-qspi.c
+++ b/drivers/spi/spi-stm32-qspi.c
@@ -397,7 +397,7 @@ static int stm32_qspi_send(struct spi_mem *mem, const struct spi_mem_op *op)
ccr |= FIELD_PREP(CCR_ADSIZE_MASK, op->addr.nbytes - 1);
}

- if (op->dummy.buswidth && op->dummy.nbytes)
+ if (op->dummy.nbytes)
ccr |= FIELD_PREP(CCR_DCYC_MASK,
op->dummy.nbytes * 8 / op->dummy.buswidth);

--
2.33.0