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From:   wanghongzhe <wanghongzhe@huawei.com>
To:     <peterhuewe@gmx.de>
CC:     <linux-integrity@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <zhangchenfeng1@huawei.com>, <wanghongzhe@huawei.com>
Subject: [PATCH] tpm: tpm_tis_spi: set cs_change = 0 when timesout
Date:   Tue, 14 Jan 2020 20:31:59 +0800
Message-ID: <1579005119-16318-1-git-send-email-wanghongzhe@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
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when i reach TPM_RETRY, the cs cannot  change back to 'high'.So the TPM chips thinks this communication is not over. 
And next times communication cannot be effective because the communications mixed up with the last time.

Signed-off-by: wanghongzhe <wanghongzhe@huawei.com>
---
 drivers/char/tpm/tpm_tis_spi.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c
index d1754fd..a1ae4f6 100644
--- a/drivers/char/tpm/tpm_tis_spi.c
+++ b/drivers/char/tpm/tpm_tis_spi.c
@@ -67,7 +67,14 @@ static int tpm_tis_spi_flow_control(struct tpm_tis_spi_phy *phy,
 		}
 
 		if (i == TPM_RETRY)
+ 		{
+ 			spi_xfer.cs_change = 0;
+ 			spi_xfer->len = 1;
+ 			spi_message_init(&m);
+ 			spi_message_add_tail(spi_xfer, &m);
+ 			ret = spi_sync_locked(phy->spi_device, &m);
 			return -ETIMEDOUT;
+ 		}
 	}
 
 	return 0;
-- 
1.7.12.4