[PATCH v3 4/5] mtd: spi-nor: cadence-quadspi: Add support to enable loop-back clock circuit
From: vigneshr@ti.com (Vignesh R)
Date: 2017-09-24 11:01:13
Also in:
linux-devicetree, lkml
Subsystem:
memory technology devices (mtd), spi nor subsystem, the rest · Maintainers:
Miquel Raynal, Richard Weinberger, Vignesh Raghavendra, Pratyush Yadav, Michael Walle, Linus Torvalds
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