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>

diff --git a/drivers/hwmon/smsc47m1.c b/drivers/hwmon/smsc47m1.c
index 8ad50fd..bfef223 100644 (file)
--- 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;