From d38fa9a155b2829b7e2cfcf8a4171b6dd3672808 Mon Sep 17 00:00:00 2001
From: Patrice Chotard <patrice.chotard@foss.st.com>
Date: Thu, 3 Jun 2021 09:34:21 +0200
Subject: [PATCH] spi: stm32-qspi: Always wait BUSY bit to be cleared in stm32_qspi_wait_cmd()
Git-commit: d38fa9a155b2829b7e2cfcf8a4171b6dd3672808
Patch-mainline: v5.13-rc6
References: git-fixes

In U-boot side, an issue has been encountered when QSPI source clock is
running at low frequency (24 MHz for example), waiting for TCF bit to be
set didn't ensure that all data has been send out the FIFO, we should also
wait that BUSY bit is cleared.

To prevent similar issue in kernel driver, we implement similar behavior
by always waiting BUSY bit to be cleared.

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Link: https://lore.kernel.org/r/20210603073421.8441-1-patrice.chotard@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/spi/spi-stm32-qspi.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-stm32-qspi.c b/drivers/spi/spi-stm32-qspi.c
index 7e640ccc7e77..594f64136208 100644
--- a/drivers/spi/spi-stm32-qspi.c
+++ b/drivers/spi/spi-stm32-qspi.c
@@ -294,7 +294,7 @@ static int stm32_qspi_wait_cmd(struct stm32_qspi *qspi,
 	int err = 0;
 
 	if (!op->data.nbytes)
-		return stm32_qspi_wait_nobusy(qspi);
+		goto wait_nobusy;
 
 	if (readl_relaxed(qspi->io_base + QSPI_SR) & SR_TCF)
 		goto out;
@@ -315,6 +315,9 @@ static int stm32_qspi_wait_cmd(struct stm32_qspi *qspi,
 out:
 	/* clear flags */
 	writel_relaxed(FCR_CTCF | FCR_CTEF, qspi->io_base + QSPI_FCR);
+wait_nobusy:
+	if (!err)
+		err = stm32_qspi_wait_nobusy(qspi);
 
 	return err;
 }
-- 
2.26.2