Re: [PATCH] i2c multiplexer driver for Proliant microserver N36L

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This patch add support to multiplexed smbus for proliant microserver
N36L and may be applicable to other configuration based on sb8xx
southbus.

root@proliant:/usr/src/lm-sensors/eddi# i2cdetect -l
i2c-0   smbus           SMBus piix4 adapter (SDA0)              SMBus adapter
i2c-1   smbus           SMBus piix4 adapter (SDA2)              SMBus adapter
i2c-2   smbus           SMBus piix4 adapter (SDA3)              SMBus adapter
i2c-3   smbus           SMBus piix4 adapter (SDA4)              SMBus adapter
root@proliant:/usr/src/lm-sensors/eddi#

yes SDA1 is reserved... so i can't multiplex it

root@proliant:/usr/src/lm-sensors/eddi# sensors
k10temp-pci-00c3
Adapter: PCI adapter
temp1:       +24.5°C  (high = +70.0°C, crit = +100.0°C)

w83795adg-i2c-1-2f
Adapter: SMBus piix4 adapter (SDA2)
in0:         +1.02 V  (min =  +0.00 V, max =  +2.05 V)
in1:         +1.52 V  (min =  +0.00 V, max =  +2.05 V)
in2:         +1.10 V  (min =  +0.00 V, max =  +2.05 V)
in3:         +0.89 V  (min =  +0.00 V, max =  +2.05 V)
in12:        +3.35 V  (min =  +0.00 V, max =  +6.14 V)
in13:        +3.28 V  (min =  +0.00 V, max =  +6.14 V)
fan1:        703 RPM  (min =  329 RPM)
temp1:       +23.0°C  (high = +109.0°C, hyst = +109.0°C)
                      (crit = +109.0°C, hyst = +109.0°C)  sensor = thermal diode
temp2:       +33.2°C  (high = +105.0°C, hyst = +105.0°C)
                      (crit = +105.0°C, hyst = +105.0°C)  sensor = thermal diode
temp5:       +14.0°C  (high = +39.0°C, hyst = +39.0°C)
                      (crit = +44.0°C, hyst = +44.0°C)  sensor = thermistor
beep_enable:disabled

jc42-i2c-0-18
Adapter: SMBus piix4 adapter (SDA0)
temp1:       +20.5°C  (low  =  +0.0°C, high =  +0.0°C)  ALARM
                      (crit =  +0.0°C, hyst =  +0.0°C)  ALARM


root@proliant:/usr/src/lm-sensors/eddi# i2cdetect -y 0
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: 50 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

root@proliant:/usr/src/lm-sensors/eddi# i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- UU
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- 61 -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

root@proliant:/usr/src/lm-sensors/eddi# i2cdetect -y 2
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- 4c -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

root@proliant:/usr/src/lm-sensors/eddi# i2cdetect -y 3
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

pay attention that the msleep seems to be really needed...

Signed-off-by: Eddi De Pieri <eddi@xxxxxxxxxxx>

Regards,

Eddi

follows patch....

diff -u -N -r 2.6.32.orig/i2c-piix4.c 2.6.32/i2c-piix4.c
--- 2.6.32.orig/i2c-piix4.c	2011-11-16 17:07:03.000000000 +0100
+++ 2.6.32/i2c-piix4.c	2011-11-16 15:21:17.000000000 +0100
@@ -97,7 +97,8 @@
 static unsigned short piix4_smba;
 static int srvrworks_csb5_delay;
 static struct pci_driver piix4_driver;
-static struct i2c_adapter piix4_adapter;
+struct i2c_adapter piix4_adapter;
+EXPORT_SYMBOL_GPL(piix4_adapter);

 static struct dmi_system_id __devinitdata piix4_dmi_blacklist[] = {
 	{
@@ -246,10 +247,22 @@
 			"0x%x already in use!\n", smba_idx);
 		return -EBUSY;
 	}
-	outb_p(smb_en, smba_idx);
-	smba_en_lo = inb_p(smba_idx + 1);
-	outb_p(smb_en + 1, smba_idx);
-	smba_en_hi = inb_p(smba_idx + 1);
+	outb_p(smb_en, smba_idx); 		//seleziono il registro 0x2c
+	smba_en_lo = inb_p(smba_idx + 1);	//leggo il dato L del registro 0x2c
+	outb_p(smb_en + 1, smba_idx);		//seleziono il registro 0x2c + 1
+	smba_en_hi = inb_p(smba_idx + 1);	//leggo il dato H del registro 0x2c
+
+	outb_p(smb_en, smba_idx); 		//seleziono il registro 0x2c
+	outb_p(smba_en_lo & 0xF9 , smba_idx + 1); //seleziono la porta 0 00 0
+	outb_p(smb_en + 1, smba_idx);		//seleziono il registro 0x2c + 1
+	outb_p(smba_en_hi, smba_idx + 1);
+
+	outb_p(smb_en, smba_idx); 		//seleziono il registro 0x2c
+	smba_en_lo = inb_p(smba_idx + 1);	//leggo il dato L del registro 0x2c
+	outb_p(smb_en + 1, smba_idx);		//seleziono il registro 0x2c + 1
+	smba_en_hi = inb_p(smba_idx + 1);	//leggo il dato H del registro 0x2c
+
+
 	release_region(smba_idx, 2);

 	if ((smba_en_lo & 1) == 0) {
@@ -258,6 +271,8 @@
 		return -ENODEV;
 	}

+	dev_info(&PIIX4_dev->dev,"Selected Default Smbus Port 0x%x",
(smba_en_lo & 0x6) >> 1);
+
 	piix4_smba = ((smba_en_hi << 8) | smba_en_lo) & 0xffe0;
 	if (acpi_check_region(piix4_smba, SMBIOSIZE, piix4_driver.name))
 		return -ENODEV;
@@ -466,7 +481,7 @@
 	.functionality	= piix4_func,
 };

-static struct i2c_adapter piix4_adapter = {
+struct i2c_adapter piix4_adapter = {
 	.owner		= THIS_MODULE,
 	.class		= I2C_CLASS_HWMON | I2C_CLASS_SPD,
 	.algo		= &smbus_algorithm,
diff -u -N -r 2.6.32.orig/i2c-piix4-n36l.c 2.6.32/i2c-piix4-n36l.c
--- 2.6.32.orig/i2c-piix4-n36l.c	1970-01-01 01:00:00.000000000 +0100
+++ 2.6.32/i2c-piix4-n36l.c	2011-11-16 16:02:01.000000000 +0100
@@ -0,0 +1,247 @@
+/*
+ * i2c-piix4-n36l.c - i2c-piix4 extras for the HP proliant
microserver n36l motherboard
+ *
+ * Copyright (C) 2004, 2008 Jean Delvare <khali@xxxxxxxxxxxx>
+ * Copyright (C) 2011  Eddi De Pieri <eddi@xxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+/*
+ * We select the channels by sending commands to the sb800 southbus
+ * the selection bit
+ * http://support.amd.com/us/Embedded_TechDocs/45482.pdf
+ *  Smbus0En - RW – 16 bits - [PM_Reg: 2Ch]
+ *  Field Name Bits Default Description
+ *  SmBus0En 0 0b Set to 1 to enable SMBUS0 function and decoding.
+ *  SmBus0Sel 2:1 00b SmBus port selection when PM_Reg 2Fh bit 0 is set to 0
+ *  00: Port 0
+ *  01: Port 2
+ *  10: Port 3
+ *  11: Port 4
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+#include <asm/io.h>
+
+extern struct i2c_adapter piix4_adapter;
+
+static struct i2c_adapter *n36l_adapter;
+static struct i2c_algorithm *n36l_algo;
+
+/* Wrapper access functions for multiplexed SMBus */
+static DEFINE_MUTEX(piix4_lock);
+
+/* We remember the last used channels combination so as to only switch
+   channels when it is really needed. This greatly reduces the SMBus
+   overhead, but also assumes that nobody will be writing to the PCA9556
+   in our back. */
+static u8 last_channels;
+
+static inline s32 piix4_access_channel(struct i2c_adapter * adap, u16 addr,
+					unsigned short flags, char read_write,
+					u8 command, int size,
+					union i2c_smbus_data * data,
+					u8 channels)
+{
+	int error;
+	unsigned short smba_idx = 0xcd6;
+	u8 smba_en_lo, smba_en_hi, smb_en = 0x2c;
+
+	mutex_lock(&piix4_lock);
+
+	if (last_channels != channels) {
+		union i2c_smbus_data mplxdata;
+		mplxdata.byte = channels;
+
+		/* Determine the address of the SMBus areas */
+		if (!request_region(smba_idx, 2, "smba_idx")) {
+			dev_err(&piix4_adapter.dev, "SMBus base address index region "
+				"0x%x already in use!\n", smba_idx);
+			return -EBUSY;
+		}
+
+		outb_p(smb_en, smba_idx); 		//seleziono il registro 0x2c
+		smba_en_lo = inb_p(smba_idx + 1);	//leggo il dato L del registro 0x2c
+		outb_p(smb_en + 1, smba_idx);		//seleziono il registro 0x2c + 1
+		smba_en_hi = inb_p(smba_idx + 1);	//leggo il dato H del registro 0x2c
+	
+		msleep(50);
+		outb_p(smb_en, smba_idx); 		//seleziono il registro 0x2c
+		outb_p((smba_en_lo & 0xF9 )+ ( channels << 1) , smba_idx + 1);
//seleziono la porta 0 00 0
+		outb_p(smb_en + 1, smba_idx);		//seleziono il registro 0x2c + 1
+		outb_p(smba_en_hi, smba_idx + 1);
+
+		msleep(50);
+
+		release_region(smba_idx, 2);
+
+		dev_info(&piix4_adapter.dev,"Selected Smbus Port 0x%x", (smba_en_lo
& 0x6) >> 1);
+
+		last_channels = channels;
+
+	}
+	
+	error = piix4_adapter.algo->smbus_xfer(adap, addr, flags, read_write,
+					      command, size, data);
+
+
+	mutex_unlock(&piix4_lock);
+	return error;
+}
+
+static s32 piix4_access_virt0(struct i2c_adapter * adap, u16 addr,
+			       unsigned short flags, char read_write,
+			       u8 command, int size,
+			       union i2c_smbus_data * data)
+{
+	return piix4_access_channel(adap, addr, flags, read_write, command,
+				     size, data, 0);
+}
+
+static s32 piix4_access_virt1(struct i2c_adapter * adap, u16 addr,
+			       unsigned short flags, char read_write,
+			       u8 command, int size,
+			       union i2c_smbus_data * data)
+{
+	return piix4_access_channel(adap, addr, flags, read_write, command,
+				     size, data, 1);
+}
+
+static s32 piix4_access_virt2(struct i2c_adapter * adap, u16 addr,
+			       unsigned short flags, char read_write,
+			       u8 command, int size,
+			       union i2c_smbus_data * data)
+{
+	return piix4_access_channel(adap, addr, flags, read_write, command,
+				     size, data, 2);
+}
+
+static s32 piix4_access_virt3(struct i2c_adapter * adap, u16 addr,
+			       unsigned short flags, char read_write,
+			       u8 command, int size,
+			       union i2c_smbus_data * data)
+{
+	return piix4_access_channel(adap, addr, flags, read_write, command,
+				     size, data, 3);
+}
+
+static int __init piix4_n36l_init(void)
+{
+	int i, error;
+
+	if (!piix4_adapter.dev.parent)
+		return -ENODEV;
+
+	printk(KERN_INFO "Configure the AMD SB800 Multiplexer\n");
+
+	/* Unregister physical bus */
+	error = i2c_del_adapter(&piix4_adapter);
+	if (error) {
+		dev_err(&piix4_adapter.dev, "Physical bus removal failed\n");
+		goto ERROR0;
+	}
+
+	printk(KERN_INFO "Enabling SMBus multiplexing for Hp Proliant
Microserver N36l\n");
+	/* Define the 4 virtual adapters and algorithms structures */
+	if (!(n36l_adapter = kzalloc(5 * sizeof(struct i2c_adapter),
+				      GFP_KERNEL))) {
+		error = -ENOMEM;
+		goto ERROR1;
+	}
+	if (!(n36l_algo = kzalloc(5 * sizeof(struct i2c_algorithm),
+				   GFP_KERNEL))) {
+		error = -ENOMEM;
+		goto ERROR2;
+	}
+
+	/* Fill in the new structures */
+	n36l_algo[0] = *(piix4_adapter.algo);
+	n36l_algo[0].smbus_xfer = piix4_access_virt0;
+	n36l_adapter[0] = piix4_adapter;
+	snprintf(n36l_adapter[0].name, sizeof(n36l_adapter[0].name),
+		 "SMBus piix4 adapter (SDA0)");
+	n36l_adapter[0].algo = n36l_algo;
+	n36l_adapter[0].dev.parent = piix4_adapter.dev.parent;
+	for (i = 1; i < 4; i++) {
+		n36l_algo[i] = *(piix4_adapter.algo);
+		n36l_adapter[i] = piix4_adapter;
+		snprintf(n36l_adapter[i].name, sizeof(n36l_adapter[i].name),
+			 "SMBus piix4 adapter (SDA%d)", i + 1);
+		n36l_adapter[i].algo = n36l_algo+i;
+		n36l_adapter[i].dev.parent = piix4_adapter.dev.parent;
+	}
+	n36l_algo[1].smbus_xfer = piix4_access_virt1;
+	n36l_algo[2].smbus_xfer = piix4_access_virt2;
+	n36l_algo[3].smbus_xfer = piix4_access_virt3;
+
+	/* Register virtual adapters */
+	for (i = 0; i < 4; i++) {
+		error = i2c_add_adapter(n36l_adapter+i);
+		if (error) {
+			printk(KERN_ERR "i2c-piix4-n36l: "
+			       "Virtual adapter %d registration "
+			       "failed, module not inserted\n", i);
+			for (i--; i >= 0; i--)
+				i2c_del_adapter(n36l_adapter+i);
+			goto ERROR3;
+		}
+	}
+
+	return 0;
+
+ERROR3:
+	kfree(n36l_algo);
+	n36l_algo = NULL;
+ERROR2:
+	kfree(n36l_adapter);
+	n36l_adapter = NULL;
+ERROR1:
+	/* Restore physical bus */
+	i2c_add_adapter(&piix4_adapter);
+ERROR0:
+	return error;
+}
+
+static void __exit piix4_n36l_exit(void)
+{
+	if (n36l_adapter) {
+		int i;
+
+		for (i = 0; i < 5; i++)
+			i2c_del_adapter(n36l_adapter+i);
+		kfree(n36l_adapter);
+		n36l_adapter = NULL;
+	}
+	kfree(n36l_algo);
+	n36l_algo = NULL;
+
+	/* Restore physical bus */
+	if (i2c_add_adapter(&piix4_adapter))
+		printk(KERN_ERR "i2c-piix4-n36l: "
+		       "Physical bus restoration failed\n");
+}
+
+MODULE_AUTHOR("Eddi De Pieri <eddi@xxxxxxxxxxx");
+MODULE_DESCRIPTION("n36l SMBus multiplexing");
+MODULE_LICENSE("GPL");
+
+module_init(piix4_n36l_init);
+module_exit(piix4_n36l_exit);


On Sun, Nov 27, 2011 at 11:55 PM, Ben Dooks <ben-i2c@xxxxxxxxx> wrote:
>
> On Fri, Nov 25, 2011 at 11:07:21PM +0100, Eddi De Pieri wrote:
>> This patch add support to multiplexed smbus for proliant microserver
>> N36L and may be applicable to other configuration based on sb8xx
>> southbus.
>>
>> root@proliant:/usr/src/lm-sensors/eddi# i2cdetect -l
>> i2c-0   smbus           SMBus piix4 adapter (SDA0)              SMBus adapter
>> i2c-1   smbus           SMBus piix4 adapter (SDA2)              SMBus adapter
>> i2c-2   smbus           SMBus piix4 adapter (SDA3)              SMBus adapter
>> i2c-3   smbus           SMBus piix4 adapter (SDA4)              SMBus adapter
>> root@proliant:/usr/src/lm-sensors/eddi#
>
> patch should go inline so it can be reviewed, thanks.
>
> --
> Ben Dooks, ben@xxxxxxxxx, http://www.fluff.org/ben/
>
> Large Hadron Colada: A large Pina Colada that makes the universe disappear.
>
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