[PATCH 2/3] spi: spi-nxp-fspi: add extra delay after dll locked

[Haibo Chen <haibo.chen@nxp.com>]

From: Han Xu <han.xu@nxp.com>

Due to the erratum ERR050272, the DLL lock status register STS2
[xREFLOCK, xSLVLOCK] bit may indicate DLL is locked before DLL is
actually locked. Add an extra 4us delay as a workaround.

refer to ERR050272, on Page 20.
https://www.nxp.com/docs/en/errata/IMX8_1N94W.pdf

Fixes: 99d822b3adc4 ("spi: spi-nxp-fspi: use DLL calibration when clock rate > 100MHz")
Signed-off-by: Han Xu <han.xu@nxp.com>
Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
---
 drivers/spi/spi-nxp-fspi.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/spi/spi-nxp-fspi.c b/drivers/spi/spi-nxp-fspi.c
index 4e82f9e900acb91c6de46559efd265f07cf4437d..96b3654b45abcaf53266ce9acac8d6578a19458a 100644
--- a/drivers/spi/spi-nxp-fspi.c
+++ b/drivers/spi/spi-nxp-fspi.c
@@ -721,6 +721,12 @@ static void nxp_fspi_dll_calibration(struct nxp_fspi *f)
 				   0, POLL_TOUT, true);
 	if (ret)
 		dev_warn(f->dev, "DLL lock failed, please fix it!\n");
+
+	/*
+	 * For ERR050272, DLL lock status bit is not accurate,
+	 * wait for 4us more as a workaround.
+	 */
+	udelay(4);
 }
 
 /*

-- 
2.34.1