Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759620Ab2BOOhJ (ORCPT ); Wed, 15 Feb 2012 09:37:09 -0500 Received: from webbox1416.server-home.net ([77.236.96.61]:42993 "EHLO webbox1416.server-home.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756162Ab2BOOhD (ORCPT ); Wed, 15 Feb 2012 09:37:03 -0500 From: Alexander Stein To: Jean Delvare , Ben Dooks , Wolfram Sang Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Stein Subject: [PATCH v2] i2c-isch: Add module parameter which actually set the clock divider Date: Wed, 15 Feb 2012 15:36:49 +0100 Message-Id: <1329316609-14570-1-git-send-email-alexander.stein@systec-electronic.com> X-Mailer: git-send-email 1.7.3.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2455 Lines: 65 It was observed the Host Clock Divider was not written by the driver. It was still set to (default) 0, if not already set by BIOS, which caused garbage on SMBus. This driver adds 2 parameters which are used to calculate the divider appropriately. This new divider is only applied if the clock divider is still default 0. Signed-off-by: Alexander Stein Tested-by: Adam Pribyl --- Changes in v2: * HSTCLK register is 16 Bit, not 8 Bit. Thanks to Adam for detecting drivers/i2c/busses/i2c-isch.c | 12 ++++++++++++ 1 files changed, 12 insertions(+), 0 deletions(-) diff --git a/drivers/i2c/busses/i2c-isch.c b/drivers/i2c/busses/i2c-isch.c index 6561d27..bdfddf8 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 +159,13 @@ 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) { + dev_notice(&sch_adapter.dev, "clock divider unitialized. Setting module defaults\n"); + dev_dbg(&sch_adapter.dev, "access speed: %d KHz\n", smbus_speed); + outw((backbone_speed / 4) / smbus_speed, SMBHSTCLK); + } + dev_dbg(&sch_adapter.dev, "access size: %d %s\n", size, (read_write)?"READ":"WRITE"); switch (size) { @@ -312,3 +322,5 @@ MODULE_AUTHOR("Jacob Pan "); MODULE_DESCRIPTION("Intel SCH SMBus driver"); MODULE_LICENSE("GPL"); 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/