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From: David Mosberger-Tang <davidm@egauge.net>
Subject: [PATCH] wifi: wilc1000: correct CRC7 calculation
Date: Wed, 07 Feb 2024 05:07:42 +0000 (UTC)
Message-Id: <20240207050736.2717641-1-davidm@egauge.net>
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To: linux-wireless@vger.kernel.org
Cc: Ajay.Kathat@microchip.com, alexis.lothore@bootlin.com, kvalo@kernel.org,
	David Mosberger-Tang <davidm@egauge.net>
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Document

    ATWILC1000/ATWILC3000
    Baremetal Wi-Fi/BLE Link Controller Software Design Guide

    https://tinyurl.com/yer2xhyc

says that bit 0 of the CRC7 code must always be a 1.

I confirmed that today with a logic analyzer: setting bit 0 causes
wilc1000 to accept a command with CRC7 enabled, whereas clearing bit 0
causes wilc1000 to reject the command with a CRC error.

Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
---
 drivers/net/wireless/microchip/wilc1000/spi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/microchip/wilc1000/spi.c b/drivers/net/wireless/microchip/wilc1000/spi.c
index 7eb0f8a421a3..b9ed88d9c33d 100644
--- a/drivers/net/wireless/microchip/wilc1000/spi.c
+++ b/drivers/net/wireless/microchip/wilc1000/spi.c
@@ -472,7 +472,7 @@ static int spi_data_write(struct wilc *wilc, u8 *b, u32 sz)
  ********************************************/
 static u8 wilc_get_crc7(u8 *buffer, u32 len)
 {
-	return crc7_be(0xfe, buffer, len);
+	return crc7_be(0xfe, buffer, len) | 0x01;
 }
 
 static int wilc_spi_single_read(struct wilc *wilc, u8 cmd, u32 adr, void *b,
-- 
2.34.1