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Subject[PATCH v4 4/6] mtd: spi-nor: cadence-quadspi: Add support to enable loop-back clock circuit
Date
Cadence QSPI IP has a adapted loop-back circuit which can be enabled by
setting BYPASS field to 0 in READCAPTURE register. It enables use of
QSPI return clock to latch the data rather than the internal QSPI
reference clock. For high speed operations, adapted loop-back circuit
using QSPI return clock helps to increase data valid window.

Based on DT parameter cdns,rclk-en enable adapted loop-back circuit
for boards which do have QSPI return clock provided.
This patch also modifies cqspi_readdata_capture() function's bypass
parameter to bool to match how its used in the function.

Signed-off-by: Vignesh R <vigneshr@ti.com>
---
drivers/mtd/spi-nor/cadence-quadspi.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c
index 5cd5d6f7303f..d9629e8f4798 100644
--- a/drivers/mtd/spi-nor/cadence-quadspi.c
+++ b/drivers/mtd/spi-nor/cadence-quadspi.c
@@ -78,6 +78,7 @@ struct cqspi_st {
bool is_decoded_cs;
u32 fifo_depth;
u32 fifo_width;
+ bool rclk_en;
u32 trigger_address;
u32 wr_delay;
struct cqspi_flash_pdata f_pdata[CQSPI_MAX_CHIPSELECT];
@@ -788,7 +789,7 @@ static void cqspi_config_baudrate_div(struct cqspi_st *cqspi)
}

static void cqspi_readdata_capture(struct cqspi_st *cqspi,
- const unsigned int bypass,
+ const bool bypass,
const unsigned int delay)
{
void __iomem *reg_base = cqspi->iobase;
@@ -852,7 +853,8 @@ static void cqspi_configure(struct spi_nor *nor)
cqspi->sclk = sclk;
cqspi_config_baudrate_div(cqspi);
cqspi_delay(nor);
- cqspi_readdata_capture(cqspi, 1, f_pdata->read_delay);
+ cqspi_readdata_capture(cqspi, !cqspi->rclk_en,
+ f_pdata->read_delay);
}

if (switch_cs || switch_ck)
@@ -1049,6 +1051,8 @@ static int cqspi_of_get_pdata(struct platform_device *pdev)
return -ENXIO;
}

+ cqspi->rclk_en = of_property_read_bool(np, "cdns,rclk-en");
+
return 0;
}

--
2.14.1
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