[PATCH v2 4/8] i2c: piix4: Move SMBus port selection into function

[Terry Bowman <terry.bowman@xxxxxxx>]

Move port selection code into a separate function. Refactor is in
preparation for following MMIO changes.

Signed-off-by: Terry Bowman <terry.bowman@xxxxxxx>
To: Guenter Roeck <linux@xxxxxxxxxxxx>
To: linux-watchdog@xxxxxxxxxxxxxxx
To: Jean Delvare <jdelvare@xxxxxxxx>
To: linux-i2c@xxxxxxxxxxxxxxx
To: Wolfram Sang <wsa@xxxxxxxxxx>
To: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
To: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: Wim Van Sebroeck <wim@xxxxxxxxxxxxxxxxxx>
Cc: Robert Richter <rrichter@xxxxxxx>
Cc: Thomas Lendacky <thomas.lendacky@xxxxxxx>
---
 drivers/i2c/busses/i2c-piix4.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index 35fcb61f4750..58b613b78c97 100644
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -700,6 +700,19 @@ static void piix4_imc_wakeup(void)
 	release_region(KERNCZ_IMC_IDX, 2);
 }
 
+static int piix4_sb800_port_sel(u8 port)
+{
+	u8 smba_en_lo;
+
+	outb_p(piix4_port_sel_sb800, SB800_PIIX4_SMB_IDX);
+	smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1);
+
+	if ((smba_en_lo & piix4_port_mask_sb800) != port)
+		outb_p((smba_en_lo & ~piix4_port_mask_sb800) | port,
+		       SB800_PIIX4_SMB_IDX + 1);
+
+	return (smba_en_lo & piix4_port_mask_sb800);
+}
 /*
  * Handles access to multiple SMBus ports on the SB800.
  * The port is selected by bits 2:1 of the smb_en register (0x2c).
@@ -716,8 +729,7 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
 	unsigned short piix4_smba = adapdata->smba;
 	int retries = MAX_TIMEOUT;
 	int smbslvcnt;
-	u8 smba_en_lo;
-	u8 port;
+	u8 prev_port;
 	int retval;
 
 	retval = piix4_sb800_region_setup(&adap->dev);
@@ -777,18 +789,12 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
 		}
 	}
 
-	outb_p(piix4_port_sel_sb800, SB800_PIIX4_SMB_IDX);
-	smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1);
-
-	port = adapdata->port;
-	if ((smba_en_lo & piix4_port_mask_sb800) != port)
-		outb_p((smba_en_lo & ~piix4_port_mask_sb800) | port,
-		       SB800_PIIX4_SMB_IDX + 1);
+	prev_port = piix4_sb800_port_sel(adapdata->port);
 
 	retval = piix4_access(adap, addr, flags, read_write,
 			      command, size, data);
 
-	outb_p(smba_en_lo, SB800_PIIX4_SMB_IDX + 1);
+	piix4_sb800_port_sel(prev_port);
 
 	/* Release the semaphore */
 	outb_p(smbslvcnt | 0x20, SMBSLVCNT);
-- 
2.30.2