From: Pratyush Yadav <p.yadav@ti.com>
To: Mark Brown <broonie@kernel.org>, Vignesh Raghavendra <vigneshr@ti.com>
Cc: Pratyush Yadav <p.yadav@ti.com>, <linux-spi@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Subject: [PATCH 4/7] spi: cadence-quadspi: Fix dummy cycle calculation when buswidth > 1
Date: Wed, 23 Dec 2020 00:14:22 +0530 [thread overview]
Message-ID: <20201222184425.7028-5-p.yadav@ti.com> (raw)
In-Reply-To: <20201222184425.7028-1-p.yadav@ti.com>
SPI MEM deals with dummy bytes but the controller deals with dummy
cycles. Multiplying bytes by 8 is correct if the dummy phase uses 1S
mode since 1 byte will be sent in 8 cycles. But if the dummy phase uses
4S mode then 1 byte will be sent in 2 cycles.
To correctly translate dummy bytes to dummy cycles, the dummy buswidth
also needs to be taken into account. Divide 8 by the buswidth to get the
correct multiplier for getting the number of cycles.
Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
---
drivers/spi/spi-cadence-quadspi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
index 6a778014ff60..376abef43530 100644
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c
@@ -294,7 +294,7 @@ static unsigned int cqspi_calc_dummy(const struct spi_mem_op *op)
{
unsigned int dummy_clk;
- dummy_clk = op->dummy.nbytes * 8;
+ dummy_clk = op->dummy.nbytes * (8 / op->dummy.buswidth);
return dummy_clk;
}
--
2.28.0
next prev parent reply other threads:[~2020-12-22 18:46 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-22 18:44 [PATCH 0/7] spi: cadence-quadspi: Add Octal DTR support Pratyush Yadav
2020-12-22 18:44 ` [PATCH 1/7] spi: cadence-quadspi: Set master max_speed_hz Pratyush Yadav
2020-12-22 18:44 ` [PATCH 2/7] spi: cadence-quadspi: Abort read if dummy cycles required are too many Pratyush Yadav
2020-12-22 18:44 ` [PATCH 3/7] spi: cadence-quadspi: Set dummy cycles from STIG commands Pratyush Yadav
2020-12-22 18:44 ` Pratyush Yadav [this message]
2020-12-22 18:44 ` [PATCH 5/7] spi: cadence-quadspi: Implement a simple supports_op hook Pratyush Yadav
2020-12-22 18:44 ` [PATCH 6/7] spi: cadence-quadspi: Wait at least 500 ms for direct reads Pratyush Yadav
2020-12-29 3:29 ` kernel test robot
2020-12-29 9:18 ` Pratyush Yadav
2021-01-05 19:41 ` Nick Desaulniers
2020-12-22 18:44 ` [PATCH 7/7] spi: cadence-quadspi: Add DTR support Pratyush Yadav
2021-01-06 14:59 ` [PATCH 0/7] spi: cadence-quadspi: Add Octal " Mark Brown
2021-01-08 16:48 ` Pratyush Yadav
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