hwmon: (lm78) Request I/O ports individually for probing

Different motherboards have different PNP declarations for LM78/LM79
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 an LM78 or LM79 chip, the useful port
range will be requested again, as a single block.

This fixes the driver on the Olivetti M3000 DT 540, at least.

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

1 files changed, 12 insertions, 13 deletions

diff --git a/drivers/hwmon/lm78.c b/drivers/hwmon/lm78.c
index cadcbd90ff3b..72ff2c4e757d 100644
--- a/drivers/hwmon/lm78.c
+++ b/drivers/hwmon/lm78.c
@@ -851,17 +851,16 @@ static struct lm78_data *lm78_update_device(struct device *dev)
 static int __init lm78_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, "lm78")) {
-		pr_debug("lm78: Failed to request low part of region\n");
-		return 0;
-	}
-	if (!request_region(address + 4, 4, "lm78")) {
-		pr_debug("lm78: 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 + LM78_EXTENT; port++) {
+		if (!request_region(port, 1, "lm78")) {
+			pr_debug("lm78: Failed to request port 0x%x\n", port);
+			goto release;
+		}
 	}
 
 #define REALLY_SLOW_IO
@@ -925,8 +924,8 @@ static int __init lm78_isa_found(unsigned short address)
 			val & 0x80 ? "LM79" : "LM78", (int)address);
 
  release:
-	release_region(address + 4, 4);
-	release_region(address, 4);
+	for (port--; port >= address; port--)
+		release_region(port, 1);
 	return found;
 }