hwmon: (w83627ehf) Use request_muxed_region

Serialize access to the hardware by using "request_muxed_region".
Call to this macro will hold off the requestor if the resource is
currently busy. "superio_enter" will return an error if call to
"request_muxed_region" fails.
Signed-off-by: Katsumi Sato <sato@toshiba-tops.co.jp>
Signed-off-by: Atsushi Nemoto <nemoto@toshiba-tops.co.jp>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/w83627ehf.c

@@ -135,11 +135,16 @@ superio_select(int ioreg, int ld)
 	outb(ld, ioreg + 1);
 }
 
-static inline void
+static inline int
 superio_enter(int ioreg)
 {
+	if (!request_muxed_region(ioreg, 2, DRVNAME))
+		return -EBUSY;
+
 	outb(0x87, ioreg);
 	outb(0x87, ioreg);
+
+	return 0;
 }
 
 static inline void
@@ -148,6 +153,7 @@ superio_exit(int ioreg)
 	outb(0xaa, ioreg);
 	outb(0x02, ioreg);
 	outb(0x02, ioreg + 1);
+	release_region(ioreg, 2);
 }
 
 /*
@@ -1970,8 +1976,6 @@ w83627ehf_check_fan_inputs(const struct w83627ehf_sio_data *sio_data,
 		return;
 	}
 
-	superio_enter(sio_data->sioreg);
-
 	/* fan4 and fan5 share some pins with the GPIO and serial flash */
 	if (sio_data->kind == nct6775) {
 		/* On NCT6775, fan4 shares pins with the fdc interface */
@@ -2013,8 +2017,6 @@ w83627ehf_check_fan_inputs(const struct w83627ehf_sio_data *sio_data,
 		fan4min = fan4pin;
 	}
 
-	superio_exit(sio_data->sioreg);
-
 	data->has_fan = data->has_fan_min = 0x03; /* fan1 and fan2 */
 	data->has_fan |= (fan3pin << 2);
 	data->has_fan_min |= (fan3pin << 2);
@@ -2352,7 +2354,11 @@ static int w83627ehf_probe(struct platform_device *pdev)
 	w83627ehf_init_device(data, sio_data->kind);
 
 	data->vrm = vid_which_vrm();
-	superio_enter(sio_data->sioreg);
+
+	err = superio_enter(sio_data->sioreg);
+	if (err)
+		goto exit_release;
+
 	/* Read VID value */
 	if (sio_data->kind == w83667hg || sio_data->kind == w83667hg_b ||
 	    sio_data->kind == nct6775 || sio_data->kind == nct6776) {
@@ -2364,8 +2370,10 @@ static int w83627ehf_probe(struct platform_device *pdev)
 		superio_select(sio_data->sioreg, W83667HG_LD_VID);
 		data->vid = superio_inb(sio_data->sioreg, 0xe3);
 		err = device_create_file(dev, &dev_attr_cpu0_vid);
-		if (err)
+		if (err) {
+			superio_exit(sio_data->sioreg);
 			goto exit_release;
+		}
 	} else if (sio_data->kind != w83627uhg) {
 		superio_select(sio_data->sioreg, W83627EHF_LD_HWM);
 		if (superio_inb(sio_data->sioreg, SIO_REG_VID_CTRL) & 0x80) {
@@ -2401,8 +2409,10 @@ static int w83627ehf_probe(struct platform_device *pdev)
 				data->vid &= 0x3f;
 
 			err = device_create_file(dev, &dev_attr_cpu0_vid);
-			if (err)
+			if (err) {
+				superio_exit(sio_data->sioreg);
 				goto exit_release;
+			}
 		} else {
 			dev_info(dev,
 				 "VID pins in output mode, CPU VID not available\n");
@@ -2424,10 +2434,10 @@ static int w83627ehf_probe(struct platform_device *pdev)
 		pr_info("Enabled fan debounce for chip %s\n", data->name);
 	}
 
-	superio_exit(sio_data->sioreg);
-
 	w83627ehf_check_fan_inputs(sio_data, data);
 
+	superio_exit(sio_data->sioreg);
+
 	/* Read fan clock dividers immediately */
 	w83627ehf_update_fan_div_common(dev, data);
 
@@ -2712,8 +2722,11 @@ static int __init w83627ehf_find(int sioaddr, unsigned short *addr,
 
 	u16 val;
 	const char *sio_name;
+	int err;
 
-	superio_enter(sioaddr);
+	err = superio_enter(sioaddr);
+	if (err)
+		return err;
 
 	if (force_id)
 		val = force_id;