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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Jean-Christophe Dubois <jcd@tribudubois.net>,
        Fabio Estevam <fabio.estevam@nxp.com>,
        Eduardo Valentin <edubezval@gmail.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.18 046/228] thermal: i.MX: Allow thermal probe to fail gracefully in case of bad calibration.
Date:   Tue,  2 Oct 2018 06:22:23 -0700
Message-Id: <20181002132502.287709813@linuxfoundation.org>
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References: <20181002132459.032960735@linuxfoundation.org>
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4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jean-Christophe Dubois <jcd@tribudubois.net>

[ Upstream commit be926ceeb4efc3bf44cb9b56f5c71aac9b1f8bbe ]

Without this fix, the thermal probe on i.MX6 might trigger a division
by zero exception later in the probe if the calibration does fail.

Note: This linux behavior (Division by zero in kernel) has been triggered
on a Qemu i.MX6 emulation where parameters in nvmem were not set. With this
fix the division by zero is not triggeed anymore as the thermal probe does
fail early.

Signed-off-by: Jean-Christophe Dubois <jcd@tribudubois.net>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/thermal/imx_thermal.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/thermal/imx_thermal.c
+++ b/drivers/thermal/imx_thermal.c
@@ -604,7 +604,10 @@ static int imx_init_from_nvmem_cells(str
 	ret = nvmem_cell_read_u32(&pdev->dev, "calib", &val);
 	if (ret)
 		return ret;
-	imx_init_calib(pdev, val);
+
+	ret = imx_init_calib(pdev, val);
+	if (ret)
+		return ret;
 
 	ret = nvmem_cell_read_u32(&pdev->dev, "temp_grade", &val);
 	if (ret)