hwmon: (smsc47m1) Only request I/O ports we really use

The I/O area of the SMSC LPC47M1xx chips which we use, gives access to
a lot of registers, some of which are related to fan speed monitoring
and control, but many are not. At the moment, the smsc47m1 driver
requests the whole I/O port range. This could easily result in
resource conflicts with either ACPI or other drivers.

Request only the I/O ports we really use, to prevent such conflicts.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Tested-by: Sean Fidler <fidlersean@gmail.com>

1 files changed, 89 insertions, 10 deletions

diff --git a/drivers/hwmon/smsc47m1.c b/drivers/hwmon/smsc47m1.c
index 8ad50fdba00d..bfef22395772 100644
--- a/drivers/hwmon/smsc47m1.c
+++ b/drivers/hwmon/smsc47m1.c
@@ -481,13 +481,94 @@ static int __init smsc47m1_find(unsigned short *addr,
         return 0;
 }
 
+#define CHECK           1
+#define REQUEST         2
+#define RELEASE         3
+
+/*
+ * This function can be used to:
+ *  - test for resource conflicts with ACPI
+ *  - request the resources
+ *  - release the resources
+ * We only allocate the I/O ports we really need, to minimize the risk of
+ * conflicts with ACPI or with other drivers.
+ */
+static int smsc47m1_handle_resources(unsigned short address, enum chips type,
+                                     int action, struct device *dev)
+{
+        static const u8 ports_m1[] = {
+                /* register, region length */
+                0x04, 1,
+                0x33, 4,
+                0x56, 7,
+        };
+
+        static const u8 ports_m2[] = {
+                /* register, region length */
+                0x04, 1,
+                0x09, 1,
+                0x2c, 2,
+                0x35, 4,
+                0x56, 7,
+                0x69, 4,
+        };
+
+        int i, ports_size, err;
+        const u8 *ports;
+
+        switch (type) {
+        case smsc47m1:
+        default:
+                ports = ports_m1;
+                ports_size = ARRAY_SIZE(ports_m1);
+                break;
+        case smsc47m2:
+                ports = ports_m2;
+                ports_size = ARRAY_SIZE(ports_m2);
+                break;
+        }
+
+        for (i = 0; i + 1 < ports_size; i += 2) {
+                unsigned short start = address + ports[i];
+                unsigned short len = ports[i + 1];
+
+                switch (action) {
+                case CHECK:
+                        /* Only check for conflicts */
+                        err = acpi_check_region(start, len, DRVNAME);
+                        if (err)
+                                return err;
+                        break;
+                case REQUEST:
+                        /* Request the resources */
+                        if (!request_region(start, len, DRVNAME)) {
+                                dev_err(dev, "Region 0x%hx-0x%hx already in "
+                                        "use!\n", start, start + len);
+
+                                /* Undo all requests */
+                                for (i -= 2; i >= 0; i -= 2)
+                                        release_region(address + ports[i],
+                                                       ports[i + 1]);
+                                return -EBUSY;
+                        }
+                        break;
+                case RELEASE:
+                        /* Release the resources */
+                        release_region(start, len);
+                        break;
+                }
+        }
+
+        return 0;
+}
+
 static int __devinit smsc47m1_probe(struct platform_device *pdev)
 {
         struct device *dev = &pdev->dev;
         struct smsc47m1_sio_data *sio_data = dev->platform_data;
         struct smsc47m1_data *data;
         struct resource *res;
-        int err = 0;
+        int err;
         int fan1, fan2, fan3, pwm1, pwm2, pwm3;
 
         static const char *names[] = {
@@ -496,12 +577,10 @@ static int __devinit smsc47m1_probe(struct platform_device *pdev)
         };
 
         res = platform_get_resource(pdev, IORESOURCE_IO, 0);
-        if (!request_region(res->start, SMSC_EXTENT, DRVNAME)) {
-                dev_err(dev, "Region 0x%lx-0x%lx already in use!\n",
-                        (unsigned long)res->start,
-                        (unsigned long)res->end);
-                return -EBUSY;
-        }
+        err = smsc47m1_handle_resources(res->start, sio_data->type,
+                                        REQUEST, dev);
+        if (err < 0)
+                return err;
 
         if (!(data = kzalloc(sizeof(struct smsc47m1_data), GFP_KERNEL))) {
                 err = -ENOMEM;
@@ -637,7 +716,7 @@ error_free:
         platform_set_drvdata(pdev, NULL);
         kfree(data);
 error_release:
-        release_region(res->start, SMSC_EXTENT);
+        smsc47m1_handle_resources(res->start, sio_data->type, RELEASE, dev);
         return err;
 }
 
@@ -650,7 +729,7 @@ static int __devexit smsc47m1_remove(struct platform_device *pdev)
         sysfs_remove_group(&pdev->dev.kobj, &smsc47m1_group);
 
         res = platform_get_resource(pdev, IORESOURCE_IO, 0);
-        release_region(res->start, SMSC_EXTENT);
+        smsc47m1_handle_resources(res->start, data->type, RELEASE, &pdev->dev);
         platform_set_drvdata(pdev, NULL);
         kfree(data);
 
@@ -717,7 +796,7 @@ static int __init smsc47m1_device_add(unsigned short address,
         };
         int err;
 
-        err = acpi_check_resource_conflict(&res);
+        err = smsc47m1_handle_resources(address, sio_data->type, CHECK, NULL);
         if (err)
                 goto exit;