It was observed the Host Clock Divider was not written by the driver. It
was still set to (default) 0 which caused garbage on SMBus.
This driver adds 2 parameters which are used to calculate the divider
appropriately.
Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-isch.c | 8 ++++++++
1 files changed, 8 insertions(+), 0 deletions(-)
diff --git a/drivers/i2c/busses/i2c-isch.c b/drivers/i2c/busses/i2c-isch.c
index 0682f8f..520bbd5 100644
--- a/drivers/i2c/busses/i2c-isch.c
+++ b/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 +59,8 @@
static unsigned short sch_smba;
static struct i2c_adapter sch_adapter;
+static int smbus_speed = 100; /* SMBus bus speed in Kbps */
+static int backbone_speed = 33000; /* backbone speed in KHz */
/*
* Start the i2c transaction -- the i2c_access will prepare the transaction
@@ -156,6 +159,9 @@ static s32 sch_access(struct i2c_adapter *adap, u16 addr,
dev_dbg(&sch_adapter.dev, "SMBus busy (%02x)\n", temp);
return -EAGAIN;
}
+ dev_dbg(&sch_adapter.dev, "access speed: %d KHz\n", smbus_speed);
+ outb((backbone_speed / 4) / smbus_speed, SMBHSTCLK);
+
dev_dbg(&sch_adapter.dev, "access size: %d %s\n", size,
(read_write)?"READ":"WRITE");
switch (size) {
@@ -323,3 +329,5 @@ MODULE_LICENSE("GPL");
module_init(i2c_sch_init);
module_exit(i2c_sch_exit);
MODULE_ALIAS("platform:isch_smbus");
+module_param(smbus_speed, int, (S_IRUSR | S_IWUSR));
+module_param(backbone_speed, int, (S_IRUSR | S_IWUSR));
--
1.7.3.4
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