[PATCH 07/12] tpm/st33zp24/spi: Improve st33zp24_spi_evaluate_latency

From: Christophe Ricard <christophe.ricard-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org,
	peterhuewe-Mmb7MZpHnFY@public.gmane.org
Cc: jean-luc.blanc-qxv4g6HH51o@public.gmane.org,
	ashley-fm2HMyfA2y6tG0bUXCXiUA@public.gmane.org,
	christophe.ricard-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
	tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
	christophe-h.ricard-qxv4g6HH51o@public.gmane.org,
	benoit.houyere-qxv4g6HH51o@public.gmane.org
Subject: [PATCH 07/12] tpm/st33zp24/spi: Improve st33zp24_spi_evaluate_latency
Date: Tue,  9 Feb 2016 10:26:56 +0100	[thread overview]
Message-ID: <1455010021-21927-8-git-send-email-christophe-h.ricard@st.com> (raw)
In-Reply-To: <1455010021-21927-1-git-send-email-christophe-h.ricard-qxv4g6HH51o@public.gmane.org>

Add check in st33zp24_spi_evaluate_latency helping to diagnose if the chip
is present or in a bad state.

Signed-off-by: Christophe Ricard <christophe-h.ricard-qxv4g6HH51o@public.gmane.org>
---
 drivers/char/tpm/st33zp24/spi.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/char/tpm/st33zp24/spi.c b/drivers/char/tpm/st33zp24/spi.c
index 0af836a..7cabf1d 100644
--- a/drivers/char/tpm/st33zp24/spi.c
+++ b/drivers/char/tpm/st33zp24/spi.c
@@ -213,6 +213,11 @@ static int st33zp24_spi_evaluate_latency(void *phy_id)
 						&data, 1);
 		latency++;
 	}
+	if (status < 0)
+		return status;
+	if (latency == MAX_SPI_LATENCY)
+		return -ENODEV;
+
 	return latency - 1;
 } /* evaluate_latency() */
 
-- 
2.5.0


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