From 1ac1909eeb52a166055d01b662b9045b9adfbcbd Mon Sep 17 00:00:00 2001
From: Alexander Stein <alexander.stein@systec-electronic.com>
Date: Mon, 28 Jan 2013 10:44:12 +0100
Subject: [PATCH] --- yaml --- r: 358799 b: refs/heads/master c:
 b08369a174a183e88baa98ab5e3566a617a3a7f8 h: refs/heads/master i:   358797:
 5cd6f191a05383fad553857d98a76631d9908845   358795:
 f3c32c6478b4ca1508d2a04ff22eda2b9e8ddf84   358791:
 e98b6ddc0ee28283fa9b3779d0c71420bcfcba4a   358783:
 1f60830daa845b611128f27e2fa501d0ac884970 v: v3

---
 [refs]                              |  2 +-
 trunk/drivers/i2c/busses/i2c-isch.c | 17 +++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index c492da7f2bf0..88d9774df5c6 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 4182b434bf760355a1516b1d3d9f73aa419eeeec
+refs/heads/master: b08369a174a183e88baa98ab5e3566a617a3a7f8
diff --git a/trunk/drivers/i2c/busses/i2c-isch.c b/trunk/drivers/i2c/busses/i2c-isch.c
index 4099f79c2280..8c38aaa7417c 100644
--- a/trunk/drivers/i2c/busses/i2c-isch.c
+++ b/trunk/drivers/i2c/busses/i2c-isch.c
@@ -40,6 +40,7 @@
 /* SCH SMBus address offsets */
 #define SMBHSTCNT	(0 + sch_smba)
 #define SMBHSTSTS	(1 + sch_smba)
+#define SMBHSTCLK	(2 + sch_smba)
 #define SMBHSTADD	(4 + sch_smba) /* TSA */
 #define SMBHSTCMD	(5 + sch_smba)
 #define SMBHSTDAT0	(6 + sch_smba)
@@ -58,6 +59,9 @@
 
 static unsigned short sch_smba;
 static struct i2c_adapter sch_adapter;
+static int backbone_speed = 33000; /* backbone speed in kHz */
+module_param(backbone_speed, int, S_IRUSR | S_IWUSR);
+MODULE_PARM_DESC(backbone_speed, "Backbone speed in kHz, (default = 33000)");
 
 /*
  * Start the i2c transaction -- the i2c_access will prepare the transaction
@@ -156,6 +160,19 @@ static s32 sch_access(struct i2c_adapter *adap, u16 addr,
 		dev_dbg(&sch_adapter.dev, "SMBus busy (%02x)\n", temp);
 		return -EAGAIN;
 	}
+	temp = inw(SMBHSTCLK);
+	if (!temp) {
+		/*
+		 * We can't determine if we have 33 or 25 MHz clock for
+		 * SMBus, so expect 33 MHz and calculate a bus clock of
+		 * 100 kHz. If we actually run at 25 MHz the bus will be
+		 * run ~75 kHz instead which should do no harm.
+		 */
+		dev_notice(&sch_adapter.dev,
+			"Clock divider unitialized. Setting defaults\n");
+		outw(backbone_speed / (4 * 100), SMBHSTCLK);
+	}
+
 	dev_dbg(&sch_adapter.dev, "access size: %d %s\n", size,
 		(read_write)?"READ":"WRITE");
 	switch (size) {