linux-kernel - [PATCH v5 02/21] hwmon: (mr75203) fix VM sensor allocation when "intel,vm-map" not defined

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Message-ID: <20220908152449.35457-3-farbere@amazon.com>
Date:   Thu, 8 Sep 2022 15:24:30 +0000
From:   Eliav Farber <farbere@...zon.com>
To:     <jdelvare@...e.com>, <linux@...ck-us.net>, <robh+dt@...nel.org>,
        <p.zabel@...gutronix.de>, <rtanwar@...linear.com>,
        <andriy.shevchenko@...el.com>, <linux-hwmon@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC:     <farbere@...zon.com>, <hhhawa@...zon.com>, <jonnyc@...zon.com>,
        "Andy Shevchenko" <andriy.shevchenko@...ux.intel.com>
Subject: [PATCH v5 02/21] hwmon: (mr75203) fix VM sensor allocation when "intel,vm-map" not defined

Bug - in case "intel,vm-map" is missing in device-tree ,'num' is set
to 0, and no voltage channel infos are allocated.

The reason num is set to 0 when "intel,vm-map" is missing is to set the
entire pvt->vm_idx[] with incremental channel numbers, but it didn't
take into consideration that same num is used later in devm_kcalloc().

If "intel,vm-map" does exist there is no need to set the unspecified
channels with incremental numbers, because the unspecified channels
can't be accessed in pvt_read_in() which is the only other place besides
the probe functions that uses pvt->vm_idx[].

This change fixes the bug by moving the incremental channel numbers
setting to be done only if "intel,vm-map" property is defined (starting
loop from 0), and removing 'num = 0'.

Fixes: 9d823351a337 ("hwmon: Add hardware monitoring driver for Moortec MR75203 PVT controller")
Signed-off-by: Eliav Farber <farbere@...zon.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
V4 -> v3:
- Simplify the fix by not removing the local num variable (it is removed as
  part of a later commit).

 drivers/hwmon/mr75203.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/hwmon/mr75203.c b/drivers/hwmon/mr75203.c
index 046523d47c29..81ccb4c6fa5c 100644
--- a/drivers/hwmon/mr75203.c
+++ b/drivers/hwmon/mr75203.c
@@ -594,7 +594,12 @@ static int mr75203_probe(struct platform_device *pdev)
 		ret = device_property_read_u8_array(dev, "intel,vm-map",
 						    pvt->vm_idx, vm_num);
 		if (ret) {
-			num = 0;
+			/*
+			 * Incase intel,vm-map property is not defined, we
+			 * assume incremental channel numbers.
+			 */
+			for (i = 0; i < vm_num; i++)
+				pvt->vm_idx[i] = i;
 		} else {
 			for (i = 0; i < vm_num; i++)
 				if (pvt->vm_idx[i] >= vm_num ||
@@ -604,13 +609,6 @@ static int mr75203_probe(struct platform_device *pdev)
 				}
 		}
 
-		/*
-		 * Incase intel,vm-map property is not defined, we assume
-		 * incremental channel numbers.
-		 */
-		for (i = num; i < vm_num; i++)
-			pvt->vm_idx[i] = i;
-
 		in_config = devm_kcalloc(dev, num + 1,
 					 sizeof(*in_config), GFP_KERNEL);
 		if (!in_config)
-- 
2.37.1