linux-kernel - [PATCH 2/2] spi: bcm-qspi: set transfer parameter only if they change

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Date:   Wed, 24 Nov 2021 14:33:53 -0500
From:   Kamal Dasu <kdasu.kdev@...il.com>
To:     broonie@...nel.org, linux-spi@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     f.fainelli@...il.com, bcm-kernel-feedback-list@...adcom.com,
        yendapally.reddy@...adcom.com, Kamal Dasu <kdasu.kdev@...il.com>
Subject: [PATCH 2/2] spi: bcm-qspi: set transfer parameter only if they change

Check if the transfer parameters have changed from previous settings
before applying new parameters.

Signed-off-by: Kamal Dasu <kdasu.kdev@...il.com>
---
 drivers/spi/spi-bcm-qspi.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/spi/spi-bcm-qspi.c b/drivers/spi/spi-bcm-qspi.c
index 38e6e2cb62ca..c9a769b8594b 100644
--- a/drivers/spi/spi-bcm-qspi.c
+++ b/drivers/spi/spi-bcm-qspi.c
@@ -598,12 +598,24 @@ static void bcm_qspi_chip_select(struct bcm_qspi *qspi, int cs)
 	qspi->curr_cs = cs;
 }
 
+static bool bcmspi_parms_did_change(const struct bcm_qspi_parms * const cur,
+				    const struct bcm_qspi_parms * const prev)
+{
+	return (cur->speed_hz != prev->speed_hz) ||
+		(cur->mode != prev->mode) ||
+		(cur->bits_per_word != prev->bits_per_word);
+}
+
+
 /* MSPI helpers */
 static void bcm_qspi_hw_set_parms(struct bcm_qspi *qspi,
 				  const struct bcm_qspi_parms *xp)
 {
 	u32 spcr, spbr = 0;
 
+	if (!bcmspi_parms_did_change(xp, &qspi->last_parms))
+		return;
+
 	if (!qspi->mspi_maj_rev)
 		/* legacy controller */
 		spcr = MSPI_MASTER_BIT;
-- 
2.17.1