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i2c: piix4: Add support for multiplexed main adapter in SB800 

The SB800 chipset supports a multiplexed main SMBus controller with
four ports. The multiplexed ports share the same SMBus address and
register set. The port is selected by bits 2:1 of the smb_en register
(0x2C).

Only one port can be active at any point in time therefore a mutex is
needed in order to synchronize access.

Additionally, the commit avoids requesting and releasing the SMBus base
address index region on every multiplexed transfer by moving the
request_region call into piix4_probe.

Tested on HP ProLiant MicroServer G7 N54L (where this patch adds
support to access sensor data from the w83795adg).

Cc: Thomas Brandon <tbrandonau@gmail.com>
Cc: Eddi De Pieri <eddi@depieri.net>
Signed-off-by: Christian Fetzer <fetzer.ch@gmail.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Christian Fetzer 2015-11-19 20:13:48 +01:00 committed by Wolfram Sang
parent ca2061e128
commit 2fee61d22e
1 changed files with 147 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

169
drivers/i2c/busses/i2c-piix4.c
View File

@ -23,6 +23,9 @@
Note: we assume there can only be one device, with one or more
SMBus interfaces.
The device can register multiple i2c_adapters (up to PIIX4_MAX_ADAPTERS).
For devices supporting multiple ports the i2c_adapter should provide
an i2c_algorithm to access them.
*/
#include <linux/module.h>
@ -37,6 +40,7 @@
#include <linux/dmi.h>
#include <linux/acpi.h>
#include <linux/io.h>
#include <linux/mutex.h>
/* PIIX4 SMBus address offsets */
@ -78,6 +82,13 @@
/* Multi-port constants */
#define PIIX4_MAX_ADAPTERS 4
/* SB800 constants */
#define SB800_PIIX4_SMB_IDX 0xcd6
/* SB800 port is selected by bits 2:1 of the smb_en register (0x2c) */
#define SB800_PIIX4_PORT_IDX 0x2c
#define SB800_PIIX4_PORT_IDX_MASK 0x06
/* insmod parameters */
/* If force is set to anything different from 0, we forcibly enable the
@ -127,6 +138,11 @@ static const struct dmi_system_id piix4_dmi_ibm[] = {
struct i2c_piix4_adapdata {
unsigned short smba;
/* SB800 */
bool sb800_main;
unsigned short port;
struct mutex *mutex;
};
static int piix4_setup(struct pci_dev *PIIX4_dev,
@ -232,7 +248,6 @@ static int piix4_setup_sb800(struct pci_dev *PIIX4_dev,
const struct pci_device_id *id, u8 aux)
{
unsigned short piix4_smba;
unsigned short smba_idx = 0xcd6;
u8 smba_en_lo, smba_en_hi, smb_en, smb_en_status;
u8 i2ccfg, i2ccfg_offset = 0x10;
@ -254,16 +269,10 @@ static int piix4_setup_sb800(struct pci_dev *PIIX4_dev,
else
smb_en = (aux) ? 0x28 : 0x2c;
if (!request_region(smba_idx, 2, "smba_idx")) {
dev_err(&PIIX4_dev->dev, "SMBus base address index region "
"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);
release_region(smba_idx, 2);
outb_p(smb_en, SB800_PIIX4_SMB_IDX);
smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1);
outb_p(smb_en + 1, SB800_PIIX4_SMB_IDX);
smba_en_hi = inb_p(SB800_PIIX4_SMB_IDX + 1);
if (!smb_en) {
smb_en_status = smba_en_lo & 0x10;
@ -527,6 +536,43 @@ static s32 piix4_access(struct i2c_adapter * adap, u16 addr,
return 0;
}
/*
* Handles access to multiple SMBus ports on the SB800.
* The port is selected by bits 2:1 of the smb_en register (0x2c).
* Returns negative errno on error.
*
* Note: The selected port must be returned to the initial selection to avoid
* problems on certain systems.
*/
static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
unsigned short flags, char read_write,
u8 command, int size, union i2c_smbus_data *data)
{
struct i2c_piix4_adapdata *adapdata = i2c_get_adapdata(adap);
u8 smba_en_lo;
u8 port;
int retval;
mutex_lock(adapdata->mutex);
outb_p(SB800_PIIX4_PORT_IDX, SB800_PIIX4_SMB_IDX);
smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1);
port = adapdata->port;
if ((smba_en_lo & SB800_PIIX4_PORT_IDX_MASK) != (port << 1))
outb_p((smba_en_lo & ~SB800_PIIX4_PORT_IDX_MASK) | (port << 1),
SB800_PIIX4_SMB_IDX + 1);
retval = piix4_access(adap, addr, flags, read_write,
command, size, data);
outb_p(smba_en_lo, SB800_PIIX4_SMB_IDX + 1);
mutex_unlock(adapdata->mutex);
return retval;
}
static u32 piix4_func(struct i2c_adapter *adapter)
{
return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
@ -539,6 +585,11 @@ static const struct i2c_algorithm smbus_algorithm = {
.functionality = piix4_func,
};
static const struct i2c_algorithm piix4_smbus_algorithm_sb800 = {
.smbus_xfer = piix4_access_sb800,
.functionality = piix4_func,
};
static const struct pci_device_id piix4_ids[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371AB_3) },
{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82443MX_3) },
@ -614,6 +665,53 @@ static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
return 0;
}
static int piix4_add_adapters_sb800(struct pci_dev *dev, unsigned short smba)
{
struct mutex *mutex;
struct i2c_piix4_adapdata *adapdata;
int port;
int retval;
mutex = kzalloc(sizeof(*mutex), GFP_KERNEL);
if (mutex == NULL)
return -ENOMEM;
mutex_init(mutex);
for (port = 0; port < PIIX4_MAX_ADAPTERS; port++) {
retval = piix4_add_adapter(dev, smba,
&piix4_main_adapters[port]);
if (retval < 0)
goto error;
piix4_main_adapters[port]->algo = &piix4_smbus_algorithm_sb800;
adapdata = i2c_get_adapdata(piix4_main_adapters[port]);
adapdata->sb800_main = true;
adapdata->port = port;
adapdata->mutex = mutex;
}
return retval;
error:
dev_err(&dev->dev,
"Error setting up SB800 adapters. Unregistering!\n");
while (--port >= 0) {
adapdata = i2c_get_adapdata(piix4_main_adapters[port]);
if (adapdata->smba) {
i2c_del_adapter(piix4_main_adapters[port]);
kfree(adapdata);
kfree(piix4_main_adapters[port]);
piix4_main_adapters[port] = NULL;
}
}
kfree(mutex);
return retval;
}
static int piix4_probe(struct pci_dev *dev, const struct pci_device_id *id)
{
int retval;
@ -621,20 +719,41 @@ static int piix4_probe(struct pci_dev *dev, const struct pci_device_id *id)
if ((dev->vendor == PCI_VENDOR_ID_ATI &&
dev->device == PCI_DEVICE_ID_ATI_SBX00_SMBUS &&
dev->revision >= 0x40) ||
dev->vendor == PCI_VENDOR_ID_AMD)
dev->vendor == PCI_VENDOR_ID_AMD) {
if (!request_region(SB800_PIIX4_SMB_IDX, 2, "smba_idx")) {
dev_err(&dev->dev,
"SMBus base address index region 0x%x already in use!\n",
SB800_PIIX4_SMB_IDX);
return -EBUSY;
}
/* base address location etc changed in SB800 */
retval = piix4_setup_sb800(dev, id, 0);
else
if (retval < 0) {
release_region(SB800_PIIX4_SMB_IDX, 2);
return retval;
}
/*
* Try to register multiplexed main SMBus adapter,
* give up if we can't
*/
retval = piix4_add_adapters_sb800(dev, retval);
if (retval < 0) {
release_region(SB800_PIIX4_SMB_IDX, 2);
return retval;
}
} else {
retval = piix4_setup(dev, id);
if (retval < 0)
return retval;
/* If no main SMBus found, give up */
if (retval < 0)
return retval;
/* Try to register main SMBus adapter, give up if we can't */
retval = piix4_add_adapter(dev, retval, &piix4_main_adapters[0]);
if (retval < 0)
return retval;
/* Try to register main SMBus adapter, give up if we can't */
retval = piix4_add_adapter(dev, retval,
&piix4_main_adapters[0]);
if (retval < 0)
return retval;
}
/* Check for auxiliary SMBus on some AMD chipsets */
retval = -ENODEV;
@ -669,7 +788,13 @@ static void piix4_adap_remove(struct i2c_adapter *adap)
if (adapdata->smba) {
i2c_del_adapter(adap);
release_region(adapdata->smba, SMBIOSIZE);
if (adapdata->port == 0) {
release_region(adapdata->smba, SMBIOSIZE);
if (adapdata->sb800_main) {
kfree(adapdata->mutex);
release_region(SB800_PIIX4_SMB_IDX, 2);
}
}
kfree(adapdata);
kfree(adap);
}