diff options
Diffstat (limited to 'drivers/i2c/busses')
| -rw-r--r-- | drivers/i2c/busses/Kconfig | 13 | ||||
| -rw-r--r-- | drivers/i2c/busses/Makefile | 1 | ||||
| -rw-r--r-- | drivers/i2c/busses/i2c-nforce2-s4985.c | 257 | ||||
| -rw-r--r-- | drivers/i2c/busses/i2c-nforce2.c | 16 |
4 files changed, 287 insertions, 0 deletions
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 48438cc5d0c..00d76e13588 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -315,6 +315,19 @@ config I2C_NFORCE2 This driver can also be built as a module. If so, the module will be called i2c-nforce2. +config I2C_NFORCE2_S4985 + tristate "SMBus multiplexing on the Tyan S4985" + depends on I2C_NFORCE2 && EXPERIMENTAL + help + Enabling this option will add specific SMBus support for the Tyan + S4985 motherboard. On this 4-CPU board, the SMBus is multiplexed + over 4 different channels, where the various memory module EEPROMs + live. Saying yes here will give you access to these in addition + to the trunk. + + This driver can also be built as a module. If so, the module + will be called i2c-nforce2-s4985. + config I2C_OCORES tristate "OpenCores I2C Controller" depends on EXPERIMENTAL diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index e8c882a5ea6..8b0a8c25790 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -24,6 +24,7 @@ obj-$(CONFIG_I2C_POWERMAC) += i2c-powermac.o obj-$(CONFIG_I2C_MPC) += i2c-mpc.o obj-$(CONFIG_I2C_MV64XXX) += i2c-mv64xxx.o obj-$(CONFIG_I2C_NFORCE2) += i2c-nforce2.o +obj-$(CONFIG_I2C_NFORCE2_S4985) += i2c-nforce2-s4985.o obj-$(CONFIG_I2C_OCORES) += i2c-ocores.o obj-$(CONFIG_I2C_OMAP) += i2c-omap.o obj-$(CONFIG_I2C_PARPORT) += i2c-parport.o diff --git a/drivers/i2c/busses/i2c-nforce2-s4985.c b/drivers/i2c/busses/i2c-nforce2-s4985.c new file mode 100644 index 00000000000..6a8995dfd0b --- /dev/null +++ b/drivers/i2c/busses/i2c-nforce2-s4985.c @@ -0,0 +1,257 @@ +/* + * i2c-nforce2-s4985.c - i2c-nforce2 extras for the Tyan S4985 motherboard + * + * Copyright (C) 2008 Jean Delvare <khali@linux-fr.org> + * + * 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 Philips + * PCA9556 chip at I2C address 0x18. The main adapter is used for + * the non-multiplexed part of the bus, and 4 virtual adapters + * are defined for the multiplexed addresses: 0x50-0x53 (memory + * module EEPROM) located on channels 1-4. We define one virtual + * adapter per CPU, which corresponds to one multiplexed channel: + * CPU0: virtual adapter 1, channel 1 + * CPU1: virtual adapter 2, channel 2 + * CPU2: virtual adapter 3, channel 3 + * CPU3: virtual adapter 4, channel 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> + +extern struct i2c_adapter *nforce2_smbus; + +static struct i2c_adapter *s4985_adapter; +static struct i2c_algorithm *s4985_algo; + +/* Wrapper access functions for multiplexed SMBus */ +static DEFINE_MUTEX(nforce2_lock); + +static s32 nforce2_access_virt0(struct i2c_adapter *adap, u16 addr, + unsigned short flags, char read_write, + u8 command, int size, + union i2c_smbus_data *data) +{ + int error; + + /* We exclude the multiplexed addresses */ + if ((addr & 0xfc) == 0x50 || (addr & 0xfc) == 0x30 + || addr == 0x18) + return -ENXIO; + + mutex_lock(&nforce2_lock); + error = nforce2_smbus->algo->smbus_xfer(adap, addr, flags, read_write, + command, size, data); + mutex_unlock(&nforce2_lock); + + return error; +} + +/* 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 nforce2_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; + + /* We exclude the non-multiplexed addresses */ + if ((addr & 0xfc) != 0x50 && (addr & 0xfc) != 0x30) + return -ENXIO; + + mutex_lock(&nforce2_lock); + if (last_channels != channels) { + union i2c_smbus_data mplxdata; + mplxdata.byte = channels; + + error = nforce2_smbus->algo->smbus_xfer(adap, 0x18, 0, + I2C_SMBUS_WRITE, 0x01, + I2C_SMBUS_BYTE_DATA, + &mplxdata); + if (error) + goto UNLOCK; + last_channels = channels; + } + error = nforce2_smbus->algo->smbus_xfer(adap, addr, flags, read_write, + command, size, data); + +UNLOCK: + mutex_unlock(&nforce2_lock); + return error; +} + +static s32 nforce2_access_virt1(struct i2c_adapter *adap, u16 addr, + unsigned short flags, char read_write, + u8 command, int size, + union i2c_smbus_data *data) +{ + /* CPU0: channel 1 enabled */ + return nforce2_access_channel(adap, addr, flags, read_write, command, + size, data, 0x02); +} + +static s32 nforce2_access_virt2(struct i2c_adapter *adap, u16 addr, + unsigned short flags, char read_write, + u8 command, int size, + union i2c_smbus_data *data) +{ + /* CPU1: channel 2 enabled */ + return nforce2_access_channel(adap, addr, flags, read_write, command, + size, data, 0x04); +} + +static s32 nforce2_access_virt3(struct i2c_adapter *adap, u16 addr, + unsigned short flags, char read_write, + u8 command, int size, + union i2c_smbus_data *data) +{ + /* CPU2: channel 3 enabled */ + return nforce2_access_channel(adap, addr, flags, read_write, command, + size, data, 0x08); +} + +static s32 nforce2_access_virt4(struct i2c_adapter *adap, u16 addr, + unsigned short flags, char read_write, + u8 command, int size, + union i2c_smbus_data *data) +{ + /* CPU3: channel 4 enabled */ + return nforce2_access_channel(adap, addr, flags, read_write, command, + size, data, 0x10); +} + +static int __init nforce2_s4985_init(void) +{ + int i, error; + union i2c_smbus_data ioconfig; + + /* Unregister physical bus */ + if (!nforce2_smbus) + return -ENODEV; + error = i2c_del_adapter(nforce2_smbus); + if (error) { + dev_err(&nforce2_smbus->dev, "Physical bus removal failed\n"); + goto ERROR0; + } + + printk(KERN_INFO "Enabling SMBus multiplexing for Tyan S4985\n"); + /* Define the 5 virtual adapters and algorithms structures */ + s4985_adapter = kzalloc(5 * sizeof(struct i2c_adapter), GFP_KERNEL); + if (!s4985_adapter) { + error = -ENOMEM; + goto ERROR1; + } + s4985_algo = kzalloc(5 * sizeof(struct i2c_algorithm), GFP_KERNEL); + if (!s4985_algo) { + error = -ENOMEM; + goto ERROR2; + } + + /* Fill in the new structures */ + s4985_algo[0] = *(nforce2_smbus->algo); + s4985_algo[0].smbus_xfer = nforce2_access_virt0; + s4985_adapter[0] = *nforce2_smbus; + s4985_adapter[0].algo = s4985_algo; + s4985_adapter[0].dev.parent = nforce2_smbus->dev.parent; + for (i = 1; i < 5; i++) { + s4985_algo[i] = *(nforce2_smbus->algo); + s4985_adapter[i] = *nforce2_smbus; + snprintf(s4985_adapter[i].name, sizeof(s4985_adapter[i].name), + "SMBus nForce2 adapter (CPU%d)", i - 1); + s4985_adapter[i].algo = s4985_algo + i; + s4985_adapter[i].dev.parent = nforce2_smbus->dev.parent; + } + s4985_algo[1].smbus_xfer = nforce2_access_virt1; + s4985_algo[2].smbus_xfer = nforce2_access_virt2; + s4985_algo[3].smbus_xfer = nforce2_access_virt3; + s4985_algo[4].smbus_xfer = nforce2_access_virt4; + + /* Configure the PCA9556 multiplexer */ + ioconfig.byte = 0x00; /* All I/O to output mode */ + error = nforce2_smbus->algo->smbus_xfer(nforce2_smbus, 0x18, 0, + I2C_SMBUS_WRITE, 0x03, + I2C_SMBUS_BYTE_DATA, &ioconfig); + if (error) { + dev_err(&nforce2_smbus->dev, "PCA9556 configuration failed\n"); + error = -EIO; + goto ERROR3; + } + + /* Register virtual adapters */ + for (i = 0; i < 5; i++) { + error = i2c_add_adapter(s4985_adapter + i); + if (error) { + dev_err(&nforce2_smbus->dev, + "Virtual adapter %d registration " + "failed, module not inserted\n", i); + for (i--; i >= 0; i--) + i2c_del_adapter(s4985_adapter + i); + goto ERROR3; + } + } + + return 0; + +ERROR3: + kfree(s4985_algo); + s4985_algo = NULL; +ERROR2: + kfree(s4985_adapter); + s4985_adapter = NULL; +ERROR1: + /* Restore physical bus */ + i2c_add_adapter(nforce2_smbus); +ERROR0: + return error; +} + +static void __exit nforce2_s4985_exit(void) +{ + if (s4985_adapter) { + int i; + + for (i = 0; i < 5; i++) + i2c_del_adapter(s4985_adapter+i); + kfree(s4985_adapter); + s4985_adapter = NULL; + } + kfree(s4985_algo); + s4985_algo = NULL; + + /* Restore physical bus */ + if (i2c_add_adapter(nforce2_smbus)) + dev_err(&nforce2_smbus->dev, "Physical bus restoration " + "failed\n"); +} + +MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); +MODULE_DESCRIPTION("S4985 SMBus multiplexing"); +MODULE_LICENSE("GPL"); + +module_init(nforce2_s4985_init); +module_exit(nforce2_s4985_exit); diff --git a/drivers/i2c/busses/i2c-nforce2.c b/drivers/i2c/busses/i2c-nforce2.c index 43c9f8df950..f95efff9b3d 100644 --- a/drivers/i2c/busses/i2c-nforce2.c +++ b/drivers/i2c/busses/i2c-nforce2.c @@ -124,6 +124,20 @@ static struct dmi_system_id __devinitdata nforce2_dmi_blacklist2[] = { static struct pci_driver nforce2_driver; +/* For multiplexing support, we need a global reference to the 1st + SMBus channel */ +#if defined CONFIG_I2C_NFORCE2_S4985 || defined CONFIG_I2C_NFORCE2_S4985_MODULE +struct i2c_adapter *nforce2_smbus; +EXPORT_SYMBOL_GPL(nforce2_smbus); + +static void nforce2_set_reference(struct i2c_adapter *adap) +{ + nforce2_smbus = adap; +} +#else +static inline void nforce2_set_reference(struct i2c_adapter *adap) { } +#endif + static void nforce2_abort(struct i2c_adapter *adap) { struct nforce2_smbus *smbus = adap->algo_data; @@ -398,6 +412,7 @@ static int __devinit nforce2_probe(struct pci_dev *dev, const struct pci_device_ return -ENODEV; } + nforce2_set_reference(&smbuses[0].adapter); return 0; } @@ -406,6 +421,7 @@ static void __devexit nforce2_remove(struct pci_dev *dev) { struct nforce2_smbus *smbuses = (void*) pci_get_drvdata(dev); + nforce2_set_reference(NULL); if (smbuses[0].base) { i2c_del_adapter(&smbuses[0].adapter); release_region(smbuses[0].base, smbuses[0].size); |