i2c: i801: make p2sb_spinlock a mutex

p2sb_spinlock is used in i801_add_tco_spt() only, and in process context
only. Therefore a mutex is sufficient, and we can make the definition
local to i801_add_tco_spt().

Reviewed-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

drivers/i2c/busses/i2c-i801.c

@@ -110,6 +110,7 @@
 #include <linux/platform_device.h>
 #include <linux/platform_data/itco_wdt.h>
 #include <linux/pm_runtime.h>
+#include <linux/mutex.h>
 
 #if IS_ENABLED(CONFIG_I2C_MUX_GPIO) && defined CONFIG_DMI
 #include <linux/gpio/machine.h>
@@ -1492,12 +1493,11 @@ static const struct itco_wdt_platform_data spt_tco_platform_data = {
 	.version = 4,
 };
 
-static DEFINE_SPINLOCK(p2sb_spinlock);
-
 static struct platform_device *
 i801_add_tco_spt(struct i801_priv *priv, struct pci_dev *pci_dev,
 		 struct resource *tco_res)
 {
+	static DEFINE_MUTEX(p2sb_mutex);
 	struct resource *res;
 	unsigned int devfn;
 	u64 base64_addr;
@@ -1510,7 +1510,7 @@ i801_add_tco_spt(struct i801_priv *priv, struct pci_dev *pci_dev,
 	 * enumerated by the PCI subsystem, so we need to unhide/hide it
 	 * to lookup the P2SB BAR.
 	 */
-	spin_lock(&p2sb_spinlock);
+	mutex_lock(&p2sb_mutex);
 
 	devfn = PCI_DEVFN(PCI_SLOT(pci_dev->devfn), 1);
 
@@ -1528,7 +1528,7 @@ i801_add_tco_spt(struct i801_priv *priv, struct pci_dev *pci_dev,
 	/* Hide the P2SB device, if it was hidden before */
 	if (hidden)
 		pci_bus_write_config_byte(pci_dev->bus, devfn, 0xe1, hidden);
-	spin_unlock(&p2sb_spinlock);
+	mutex_unlock(&p2sb_mutex);
 
 	res = &tco_res[1];
 	if (pci_dev->device == PCI_DEVICE_ID_INTEL_DNV_SMBUS)