linux-kernel - [PATCH 5.15 008/132] i2c: piix4: Move SMBus port selection into function

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Message-Id: <20220523165824.975018684@linuxfoundation.org>
Date:   Mon, 23 May 2022 19:03:37 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Terry Bowman <terry.bowman@....com>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Jean Delvare <jdelvare@...e.de>, Wolfram Sang <wsa@...nel.org>,
        Mario Limonciello <Mario.Limonciello@....com>
Subject: [PATCH 5.15 008/132] i2c: piix4: Move SMBus port selection into function

From: Terry Bowman <terry.bowman@....com>

commit fbafbd51bff52cb3a920fd98d4dae2a78dd433d0 upstream.

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

Signed-off-by: Terry Bowman <terry.bowman@....com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
Reviewed-by: Jean Delvare <jdelvare@...e.de>
Signed-off-by: Wolfram Sang <wsa@...nel.org>
Cc: Mario Limonciello <Mario.Limonciello@....com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/i2c/busses/i2c-piix4.c |   27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -698,6 +698,20 @@ static void piix4_imc_wakeup(void)
 	release_region(KERNCZ_IMC_IDX, 2);
 }
 
+static int piix4_sb800_port_sel(u8 port)
+{
+	u8 smba_en_lo, val;
+
+	outb_p(piix4_port_sel_sb800, SB800_PIIX4_SMB_IDX);
+	smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1);
+
+	val = (smba_en_lo & ~piix4_port_mask_sb800) | port;
+	if (smba_en_lo != val)
+		outb_p(val, 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).
@@ -714,8 +728,7 @@ static s32 piix4_access_sb800(struct i2c
 	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_request(&adap->dev);
@@ -775,18 +788,12 @@ static s32 piix4_access_sb800(struct i2c
 		}
 	}
 
-	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);