hwmon: (w83781d) Request I/O ports individually for probing

Different motherboards have different PNP declarations for
W83781D/W83782D chips. Some declare the whole range of I/O ports (8
ports), some declare only the useful ports (2 ports at offset 5) and
some declare fancy ranges, for example 4 ports at offset 4. To
properly handle all cases, request all ports individually for probing.
After we have determined that we really have a W83781D or W83782D
chip, the useful port range will be requested again, as a single
block.

I did not see a board which needs this yet, but I know of one for lm78
driver and I'd like to keep the logic of these two drivers in sync.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: stable@kernel.org

1 files changed, 13 insertions, 13 deletions

diff --git a/drivers/hwmon/w83781d.c b/drivers/hwmon/w83781d.c
index 05f9225b6f94..32d4adee73db 100644
--- a/drivers/hwmon/w83781d.c
+++ b/drivers/hwmon/w83781d.c
@@ -1793,17 +1793,17 @@ static int __init
 w83781d_isa_found(unsigned short address)
 {
         int val, save, found = 0;
-
-        /* We have to request the region in two parts because some
-           boards declare base+4 to base+7 as a PNP device */
-        if (!request_region(address, 4, "w83781d")) {
-                pr_debug("w83781d: Failed to request low part of region\n");
-                return 0;
-        }
-        if (!request_region(address + 4, 4, "w83781d")) {
-                pr_debug("w83781d: Failed to request high part of region\n");
-                release_region(address, 4);
-                return 0;
+        int port;
+
+        /* Some boards declare base+0 to base+7 as a PNP device, some base+4
+         * to base+7 and some base+5 to base+6. So we better request each port
+         * individually for the probing phase. */
+        for (port = address; port < address + W83781D_EXTENT; port++) {
+                if (!request_region(port, 1, "w83781d")) {
+                        pr_debug("w83781d: Failed to request port 0x%x\n",
+                                 port);
+                        goto release;
+                }
         }
 
 #define REALLY_SLOW_IO
@@ -1877,8 +1877,8 @@ w83781d_isa_found(unsigned short address)
                         val == 0x30 ? "W83782D" : "W83781D", (int)address);
 
  release:
-        release_region(address + 4, 4);
-        release_region(address, 4);
+        for (port--; port >= address; port--)
+                release_region(port, 1);
         return found;
 }