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: e6dc6d6dd8bd ("hwmon: Add hardware monitoring driver for Moortec MR75203 PVT controller")
Signed-off-by: Eliav Farber <farbere@amazon.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220908152449.35457-3-farbere@amazon.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/mr75203.c b/drivers/hwmon/mr75203.c
index 26278b0f17a989ac0a6a23bcd5dc8d5143bd46e6..8b72e8fe34c1bd9ae28e9fdeeea27f09250ed251 100644 (file)
--- a/drivers/hwmon/mr75203.c
+++ b/drivers/hwmon/mr75203.c
@@ -584,7 +584,12 @@ 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 ||
@@ -594,13 +599,6 @@ 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)