diff options
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/Kconfig | 13 | ||||
| -rw-r--r-- | drivers/i2c/Makefile | 3 | ||||
| -rw-r--r-- | drivers/i2c/i2c-core.c | 158 | ||||
| -rw-r--r-- | drivers/i2c/i2c-dev.c | 66 | ||||
| -rw-r--r-- | drivers/i2c/i2c-mux.c | 165 | ||||
| -rw-r--r-- | drivers/i2c/muxes/Kconfig | 18 | ||||
| -rw-r--r-- | drivers/i2c/muxes/Makefile | 8 | ||||
| -rw-r--r-- | drivers/i2c/muxes/pca954x.c | 301 |
8 files changed, 671 insertions, 61 deletions
diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig index d06083fdffb..30f06e956bf 100644 --- a/drivers/i2c/Kconfig +++ b/drivers/i2c/Kconfig @@ -47,6 +47,19 @@ config I2C_CHARDEV This support is also available as a module. If so, the module will be called i2c-dev. +config I2C_MUX + tristate "I2C bus multiplexing support" + depends on EXPERIMENTAL + help + Say Y here if you want the I2C core to support the ability to + handle multiplexed I2C bus topologies, by presenting each + multiplexed segment as a I2C adapter. + + This support is also available as a module. If so, the module + will be called i2c-mux. + +source drivers/i2c/muxes/Kconfig + config I2C_HELPER_AUTO bool "Autoselect pertinent helper modules" default y diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile index a7d9b4be9bb..c00fd66388f 100644 --- a/drivers/i2c/Makefile +++ b/drivers/i2c/Makefile @@ -6,7 +6,8 @@ obj-$(CONFIG_I2C_BOARDINFO) += i2c-boardinfo.o obj-$(CONFIG_I2C) += i2c-core.o obj-$(CONFIG_I2C_SMBUS) += i2c-smbus.o obj-$(CONFIG_I2C_CHARDEV) += i2c-dev.o -obj-y += algos/ busses/ +obj-$(CONFIG_I2C_MUX) += i2c-mux.o +obj-y += algos/ busses/ muxes/ ifeq ($(CONFIG_I2C_DEBUG_CORE),y) EXTRA_CFLAGS += -DDEBUG diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index df937df845e..6649176de94 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -20,7 +20,9 @@ /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>. All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl> SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and - Jean Delvare <khali@linux-fr.org> */ + Jean Delvare <khali@linux-fr.org> + Mux support by Rodolfo Giometti <giometti@enneenne.com> and + Michael Lawnick <michael.lawnick.ext@nsn.com> */ #include <linux/module.h> #include <linux/kernel.h> @@ -423,11 +425,87 @@ static int __i2c_check_addr_busy(struct device *dev, void *addrp) return 0; } +/* walk up mux tree */ +static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr) +{ + int result; + + result = device_for_each_child(&adapter->dev, &addr, + __i2c_check_addr_busy); + + if (!result && i2c_parent_is_i2c_adapter(adapter)) + result = i2c_check_mux_parents( + to_i2c_adapter(adapter->dev.parent), addr); + + return result; +} + +/* recurse down mux tree */ +static int i2c_check_mux_children(struct device *dev, void *addrp) +{ + int result; + + if (dev->type == &i2c_adapter_type) + result = device_for_each_child(dev, addrp, + i2c_check_mux_children); + else + result = __i2c_check_addr_busy(dev, addrp); + + return result; +} + static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr) { - return device_for_each_child(&adapter->dev, &addr, - __i2c_check_addr_busy); + int result = 0; + + if (i2c_parent_is_i2c_adapter(adapter)) + result = i2c_check_mux_parents( + to_i2c_adapter(adapter->dev.parent), addr); + + if (!result) + result = device_for_each_child(&adapter->dev, &addr, + i2c_check_mux_children); + + return result; +} + +/** + * i2c_lock_adapter - Get exclusive access to an I2C bus segment + * @adapter: Target I2C bus segment + */ +void i2c_lock_adapter(struct i2c_adapter *adapter) +{ + if (i2c_parent_is_i2c_adapter(adapter)) + i2c_lock_adapter(to_i2c_adapter(adapter->dev.parent)); + else + rt_mutex_lock(&adapter->bus_lock); +} +EXPORT_SYMBOL_GPL(i2c_lock_adapter); + +/** + * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment + * @adapter: Target I2C bus segment + */ +static int i2c_trylock_adapter(struct i2c_adapter *adapter) +{ + if (i2c_parent_is_i2c_adapter(adapter)) + return i2c_trylock_adapter(to_i2c_adapter(adapter->dev.parent)); + else + return rt_mutex_trylock(&adapter->bus_lock); +} + +/** + * i2c_unlock_adapter - Release exclusive access to an I2C bus segment + * @adapter: Target I2C bus segment + */ +void i2c_unlock_adapter(struct i2c_adapter *adapter) +{ + if (i2c_parent_is_i2c_adapter(adapter)) + i2c_unlock_adapter(to_i2c_adapter(adapter->dev.parent)); + else + rt_mutex_unlock(&adapter->bus_lock); } +EXPORT_SYMBOL_GPL(i2c_unlock_adapter); /** * i2c_new_device - instantiate an i2c device @@ -633,9 +711,9 @@ i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr, return -EINVAL; /* Keep track of the added device */ - i2c_lock_adapter(adap); + mutex_lock(&adap->userspace_clients_lock); list_add_tail(&client->detected, &adap->userspace_clients); - i2c_unlock_adapter(adap); + mutex_unlock(&adap->userspace_clients_lock); dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device", info.type, info.addr); @@ -674,7 +752,7 @@ i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr, /* Make sure the device was added through sysfs */ res = -ENOENT; - i2c_lock_adapter(adap); + mutex_lock(&adap->userspace_clients_lock); list_for_each_entry_safe(client, next, &adap->userspace_clients, detected) { if (client->addr == addr) { @@ -687,7 +765,7 @@ i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr, break; } } - i2c_unlock_adapter(adap); + mutex_unlock(&adap->userspace_clients_lock); if (res < 0) dev_err(dev, "%s: Can't find device in list\n", @@ -714,10 +792,11 @@ static const struct attribute_group *i2c_adapter_attr_groups[] = { NULL }; -static struct device_type i2c_adapter_type = { +struct device_type i2c_adapter_type = { .groups = i2c_adapter_attr_groups, .release = i2c_adapter_dev_release, }; +EXPORT_SYMBOL_GPL(i2c_adapter_type); #ifdef CONFIG_I2C_COMPAT static struct class_compat *i2c_adapter_compat_class; @@ -760,7 +839,7 @@ static int __process_new_adapter(struct device_driver *d, void *data) static int i2c_register_adapter(struct i2c_adapter *adap) { - int res = 0, dummy; + int res = 0; /* Can't register until after driver model init */ if (unlikely(WARN_ON(!i2c_bus_type.p))) { @@ -769,6 +848,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap) } rt_mutex_init(&adap->bus_lock); + mutex_init(&adap->userspace_clients_lock); INIT_LIST_HEAD(&adap->userspace_clients); /* Set default timeout to 1 second if not already set */ @@ -801,8 +881,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap) /* Notify drivers */ mutex_lock(&core_lock); - dummy = bus_for_each_drv(&i2c_bus_type, NULL, adap, - __process_new_adapter); + bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter); mutex_unlock(&core_lock); return 0; @@ -975,7 +1054,7 @@ int i2c_del_adapter(struct i2c_adapter *adap) return res; /* Remove devices instantiated from sysfs */ - i2c_lock_adapter(adap); + mutex_lock(&adap->userspace_clients_lock); list_for_each_entry_safe(client, next, &adap->userspace_clients, detected) { dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name, @@ -983,7 +1062,7 @@ int i2c_del_adapter(struct i2c_adapter *adap) list_del(&client->detected); i2c_unregister_device(client); } - i2c_unlock_adapter(adap); + mutex_unlock(&adap->userspace_clients_lock); /* Detach any active clients. This can't fail, thus we do not checking the returned value. */ @@ -1238,12 +1317,12 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) #endif if (in_atomic() || irqs_disabled()) { - ret = rt_mutex_trylock(&adap->bus_lock); + ret = i2c_trylock_adapter(adap); if (!ret) /* I2C activity is ongoing. */ return -EAGAIN; } else { - rt_mutex_lock(&adap->bus_lock); + i2c_lock_adapter(adap); } /* Retry automatically on arbitration loss */ @@ -1255,7 +1334,7 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) if (time_after(jiffies, orig_jiffies + adap->timeout)) break; } - rt_mutex_unlock(&adap->bus_lock); + i2c_unlock_adapter(adap); return ret; } else { @@ -1350,13 +1429,17 @@ static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr) I2C_SMBUS_BYTE_DATA, &dummy); else #endif - if ((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50 - || !i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK)) - err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, - I2C_SMBUS_BYTE, &dummy); - else + if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50) + && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK)) err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0, I2C_SMBUS_QUICK, NULL); + else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE)) + err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, + I2C_SMBUS_BYTE, &dummy); + else { + dev_warn(&adap->dev, "No suitable probing method supported\n"); + err = -EOPNOTSUPP; + } return err >= 0; } @@ -1437,16 +1520,6 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver) if (!(adapter->class & driver->class)) goto exit_free; - /* Stop here if the bus doesn't support probing */ - if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE)) { - if (address_list[0] == I2C_CLIENT_END) - goto exit_free; - - dev_warn(&adapter->dev, "Probing not supported\n"); - err = -EOPNOTSUPP; - goto exit_free; - } - for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) { dev_dbg(&adapter->dev, "found normal entry for adapter %d, " "addr 0x%02x\n", adap_id, address_list[i]); @@ -1461,18 +1534,23 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver) return err; } +int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr) +{ + return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, + I2C_SMBUS_QUICK, NULL) >= 0; +} +EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read); + struct i2c_client * i2c_new_probed_device(struct i2c_adapter *adap, struct i2c_board_info *info, - unsigned short const *addr_list) + unsigned short const *addr_list, + int (*probe)(struct i2c_adapter *, unsigned short addr)) { int i; - /* Stop here if the bus doesn't support probing */ - if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE)) { - dev_err(&adap->dev, "Probing not supported\n"); - return NULL; - } + if (!probe) + probe = i2c_default_probe; for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) { /* Check address validity */ @@ -1490,7 +1568,7 @@ i2c_new_probed_device(struct i2c_adapter *adap, } /* Test address responsiveness */ - if (i2c_default_probe(adap, addr_list[i])) + if (probe(adap, addr_list[i])) break; } @@ -2002,7 +2080,7 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags, flags &= I2C_M_TEN | I2C_CLIENT_PEC; if (adapter->algo->smbus_xfer) { - rt_mutex_lock(&adapter->bus_lock); + i2c_lock_adapter(adapter); /* Retry automatically on arbitration loss */ orig_jiffies = jiffies; @@ -2016,7 +2094,7 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags, orig_jiffies + adapter->timeout)) break; } - rt_mutex_unlock(&adapter->bus_lock); + i2c_unlock_adapter(adapter); } else res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write, command, protocol, data); diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c index e0694e4d86c..5f3a52d517c 100644 --- a/drivers/i2c/i2c-dev.c +++ b/drivers/i2c/i2c-dev.c @@ -167,13 +167,9 @@ static ssize_t i2cdev_write(struct file *file, const char __user *buf, if (count > 8192) count = 8192; - tmp = kmalloc(count, GFP_KERNEL); - if (tmp == NULL) - return -ENOMEM; - if (copy_from_user(tmp, buf, count)) { - kfree(tmp); - return -EFAULT; - } + tmp = memdup_user(buf, count); + if (IS_ERR(tmp)) + return PTR_ERR(tmp); pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n", iminor(file->f_path.dentry->d_inode), count); @@ -193,12 +189,50 @@ static int i2cdev_check(struct device *dev, void *addrp) return dev->driver ? -EBUSY : 0; } +/* walk up mux tree */ +static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr) +{ + int result; + + result = device_for_each_child(&adapter->dev, &addr, i2cdev_check); + + if (!result && i2c_parent_is_i2c_adapter(adapter)) + result = i2cdev_check_mux_parents( + to_i2c_adapter(adapter->dev.parent), addr); + + return result; +} + +/* recurse down mux tree */ +static int i2cdev_check_mux_children(struct device *dev, void *addrp) +{ + int result; + + if (dev->type == &i2c_adapter_type) + result = device_for_each_child(dev, addrp, + i2cdev_check_mux_children); + else + result = i2cdev_check(dev, addrp); + + return result; +} + /* This address checking function differs from the one in i2c-core in that it considers an address with a registered device, but no driver bound to it, as NOT busy. */ static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr) { - return device_for_each_child(&adapter->dev, &addr, i2cdev_check); + int result = 0; + + if (i2c_parent_is_i2c_adapter(adapter)) + result = i2cdev_check_mux_parents( + to_i2c_adapter(adapter->dev.parent), addr); + + if (!result) + result = device_for_each_child(&adapter->dev, &addr, + i2cdev_check_mux_children); + + return result; } static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client, @@ -219,9 +253,7 @@ static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client, if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS) return -EINVAL; - rdwr_pa = (struct i2c_msg *) - kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg), - GFP_KERNEL); + rdwr_pa = kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg), GFP_KERNEL); if (!rdwr_pa) return -ENOMEM; @@ -247,15 +279,9 @@ static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client, break; } data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf; - rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL); - if (rdwr_pa[i].buf == NULL) { - res = -ENOMEM; - break; - } - if (copy_from_user(rdwr_pa[i].buf, data_ptrs[i], - rdwr_pa[i].len)) { - ++i; /* Needs to be kfreed too */ - res = -EFAULT; + rdwr_pa[i].buf = memdup_user(data_ptrs[i], rdwr_pa[i].len); + if (IS_ERR(rdwr_pa[i].buf)) { + res = PTR_ERR(rdwr_pa[i].buf); break; } } diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c new file mode 100644 index 00000000000..d32a4843fc3 --- /dev/null +++ b/drivers/i2c/i2c-mux.c @@ -0,0 +1,165 @@ +/* + * Multiplexed I2C bus driver. + * + * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it> + * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it> + * Copyright (c) 2009-2010 NSN GmbH & Co KG <michael.lawnick.ext@nsn.com> + * + * Simplifies access to complex multiplexed I2C bus topologies, by presenting + * each multiplexed bus segment as an additional I2C adapter. + * Supports multi-level mux'ing (mux behind a mux). + * + * Based on: + * i2c-virt.c from Kumar Gala <galak@kernel.crashing.org> + * i2c-virtual.c from Ken Harrenstien, Copyright (c) 2004 Google, Inc. + * i2c-virtual.c from Brian Kuschak <bkuschak@yahoo.com> + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/i2c.h> +#include <linux/i2c-mux.h> + +/* multiplexer per channel data */ +struct i2c_mux_priv { + struct i2c_adapter adap; + struct i2c_algorithm algo; + + struct i2c_adapter *parent; + void *mux_dev; /* the mux chip/device */ + u32 chan_id; /* the channel id */ + + int (*select)(struct i2c_adapter *, void *mux_dev, u32 chan_id); + int (*deselect)(struct i2c_adapter *, void *mux_dev, u32 chan_id); +}; + +static int i2c_mux_master_xfer(struct i2c_adapter *adap, + struct i2c_msg msgs[], int num) +{ + struct i2c_mux_priv *priv = adap->algo_data; + struct i2c_adapter *parent = priv->parent; + int ret; + + /* Switch to the right mux port and perform the transfer. */ + + ret = priv->select(parent, priv->mux_dev, priv->chan_id); + if (ret >= 0) + ret = parent->algo->master_xfer(parent, msgs, num); + if (priv->deselect) + priv->deselect(parent, priv->mux_dev, priv->chan_id); + + return ret; +} + +static int i2c_mux_smbus_xfer(struct i2c_adapter *adap, + u16 addr, unsigned short flags, + char read_write, u8 command, + int size, union i2c_smbus_data *data) +{ + struct i2c_mux_priv *priv = adap->algo_data; + struct i2c_adapter *parent = priv->parent; + int ret; + + /* Select the right mux port and perform the transfer. */ + + ret = priv->select(parent, priv->mux_dev, priv->chan_id); + if (ret >= 0) + ret = parent->algo->smbus_xfer(parent, addr, flags, + read_write, command, size, data); + if (priv->deselect) + priv->deselect(parent, priv->mux_dev, priv->chan_id); + + return ret; +} + +/* Return the parent's functionality */ +static u32 i2c_mux_functionality(struct i2c_adapter *adap) +{ + struct i2c_mux_priv *priv = adap->algo_data; + struct i2c_adapter *parent = priv->parent; + + return parent->algo->functionality(parent); +} + +struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent, + void *mux_dev, u32 force_nr, u32 chan_id, + int (*select) (struct i2c_adapter *, + void *, u32), + int (*deselect) (struct i2c_adapter *, + void *, u32)) +{ + struct i2c_mux_priv *priv; + int ret; + + priv = kzalloc(sizeof(struct i2c_mux_priv), GFP_KERNEL); + if (!priv) + return NULL; + + /* Set up private adapter data */ + priv->parent = parent; + priv->mux_dev = mux_dev; + priv->chan_id = chan_id; + priv->select = select; + priv->deselect = deselect; + + /* Need to do algo dynamically because we don't know ahead + * of time what sort of physical adapter we'll be dealing with. + */ + if (parent->algo->master_xfer) + priv->algo.master_xfer = i2c_mux_master_xfer; + if (parent->algo->smbus_xfer) + priv->algo.smbus_xfer = i2c_mux_smbus_xfer; + priv->algo.functionality = i2c_mux_functionality; + + /* Now fill out new adapter structure */ + snprintf(priv->adap.name, sizeof(priv->adap.name), + "i2c-%d-mux (chan_id %d)", i2c_adapter_id(parent), chan_id); + priv->adap.owner = THIS_MODULE; + priv->adap.id = parent->id; + priv->adap.algo = &priv->algo; + priv->adap.algo_data = priv; + priv->adap.dev.parent = &parent->dev; + + if (force_nr) { + priv->adap.nr = force_nr; + ret = i2c_add_numbered_adapter(&priv->adap); + } else { + ret = i2c_add_adapter(&priv->adap); + } + if (ret < 0) { + dev_err(&parent->dev, + "failed to add mux-adapter (error=%d)\n", + ret); + kfree(priv); + return NULL; + } + + dev_info(&parent->dev, "Added multiplexed i2c bus %d\n", + i2c_adapter_id(&priv->adap)); + + return &priv->adap; +} +EXPORT_SYMBOL_GPL(i2c_add_mux_adapter); + +int i2c_del_mux_adapter(struct i2c_adapter *adap) +{ + struct i2c_mux_priv *priv = adap->algo_data; + int ret; + + ret = i2c_del_adapter(adap); + if (ret < 0) + return ret; + kfree(priv); + + return 0; +} +EXPORT_SYMBOL_GPL(i2c_del_mux_adapter); + +MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>"); +MODULE_DESCRIPTION("I2C driver for multiplexed I2C busses"); +MODULE_LICENSE("GPL v2"); diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig new file mode 100644 index 00000000000..4c9a99c4fcb --- /dev/null +++ b/drivers/i2c/muxes/Kconfig @@ -0,0 +1,18 @@ +# +# Multiplexer I2C chip drivers configuration +# + +menu "Multiplexer I2C Chip support" + depends on I2C_MUX + +config I2C_MUX_PCA954x + tristate "Philips PCA954x I2C Mux/switches" + depends on EXPERIMENTAL + help + If you say yes here you get support for the Philips PCA954x + I2C mux/switch devices. + + This driver can also be built as a module. If so, the module + will be called pca954x. + +endmenu diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile new file mode 100644 index 00000000000..bd83b527481 --- /dev/null +++ b/drivers/i2c/muxes/Makefile @@ -0,0 +1,8 @@ +# +# Makefile for multiplexer I2C chip drivers. + +obj-$(CONFIG_I2C_MUX_PCA954x) += pca954x.o + +ifeq ($(CONFIG_I2C_DEBUG_BUS),y) +EXTRA_CFLAGS += -DDEBUG +endif diff --git a/drivers/i2c/muxes/pca954x.c b/drivers/i2c/muxes/pca954x.c new file mode 100644 index 00000000000..6f9accf3189 --- /dev/null +++ b/drivers/i2c/muxes/pca954x.c @@ -0,0 +1,301 @@ +/* + * I2C multiplexer + * + * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it> + * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it> + * + * This module supports the PCA954x series of I2C multiplexer/switch chips + * made by Philips Semiconductors. + * This includes the: + * PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547 + * and PCA9548. + * + * These chips are all controlled via the I2C bus itself, and all have a + * single 8-bit register. The upstream "parent" bus fans out to two, + * four, or eight downstream busses or channels; which of these + * are selected is determined by the chip type and register contents. A + * mux can select only one sub-bus at a time; a switch can select any + * combination simultaneously. + * + * Based on: + * pca954x.c from Kumar Gala <galak@kernel.crashing.org> + * Copyright (C) 2006 + * + * Based on: + * pca954x.c from Ken Harrenstien + * Copyright (C) 2004 Google, Inc. (Ken Harrenstien) + * + * Based on: + * i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com> + * and + * pca9540.c from Jean Delvare <khali@linux-fr.org>. + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/device.h> +#include <linux/i2c.h> +#include <linux/i2c-mux.h> + +#include <linux/i2c/pca954x.h> + +#define PCA954X_MAX_NCHANS 8 + +enum pca_type { + pca_9540, + pca_9542, + pca_9543, + pca_9544, + pca_9545, + pca_9546, + pca_9547, + pca_9548, +}; + +struct pca954x { + enum pca_type type; + struct i2c_adapter *virt_adaps[PCA954X_MAX_NCHANS]; + + u8 last_chan; /* last register value */ +}; + +struct chip_desc { + u8 nchans; + u8 enable; /* used for muxes only */ + enum muxtype { + pca954x_ismux = 0, + pca954x_isswi + } muxtype; +}; + +/* Provide specs for the PCA954x types we know about */ +static const struct chip_desc chips[] = { + [pca_9540] = { + .nchans = 2, + .enable = 0x4, + .muxtype = pca954x_ismux, + }, + [pca_9543] = { + .nchans = 2, + .muxtype = pca954x_isswi, + }, + [pca_9544] = { + .nchans = 4, + .enable = 0x4, + .muxtype = pca954x_ismux, + }, + [pca_9545] = { + .nchans = 4, + .muxtype = pca954x_isswi, + }, + [pca_9547] = { + .nchans = 8, + .enable = 0x8, + .muxtype = pca954x_ismux, + }, + [pca_9548] = { + .nchans = 8, + .muxtype = pca954x_isswi, + }, +}; + +static const struct i2c_device_id pca954x_id[] = { + { "pca9540", pca_9540 }, + { "pca9542", pca_9540 }, + { "pca9543", pca_9543 }, + { "pca9544", pca_9544 }, + { "pca9545", pca_9545 }, + { "pca9546", pca_9545 }, + { "pca9547", pca_9547 }, + { "pca9548", pca_9548 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, pca954x_id); + +/* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer() + for this as they will try to lock adapter a second time */ +static int pca954x_reg_write(struct i2c_adapter *adap, + struct i2c_client *client, u8 val) +{ + int ret = -ENODEV; + + if (adap->algo->master_xfer) { + struct i2c_msg msg; + char buf[1]; + + msg.addr = client->addr; + msg.flags = 0; + msg.len = 1; + buf[0] = val; + msg.buf = buf; + ret = adap->algo->master_xfer(adap, &msg, 1); + } else { + union i2c_smbus_data data; + ret = adap->algo->smbus_xfer(adap, client->addr, + client->flags, + I2C_SMBUS_WRITE, + val, I2C_SMBUS_BYTE, &data); + } + + return ret; +} + +static int pca954x_select_chan(struct i2c_adapter *adap, + void *client, u32 chan) +{ + struct pca954x *data = i2c_get_clientdata(client); + const struct chip_desc *chip = &chips[data->type]; + u8 regval; + int ret = 0; + + /* we make switches look like muxes, not sure how to be smarter */ + if (chip->muxtype == pca954x_ismux) + regval = chan | chip->enable; + else + regval = 1 << chan; + + /* Only select the channel if its different from the last channel */ + if (data->last_chan != regval) { + ret = pca954x_reg_write(adap, client, regval); + data->last_chan = regval; + } + + return ret; +} + +static int pca954x_deselect_mux(struct i2c_adapter *adap, + void *client, u32 chan) +{ + struct pca954x *data = i2c_get_clientdata(client); + + /* Deselect active channel */ + data->last_chan = 0; + return pca954x_reg_write(adap, client, data->last_chan); +} + +/* + * I2C init/probing/exit functions + */ +static int __devinit pca954x_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent); + struct pca954x_platform_data *pdata = client->dev.platform_data; + int num, force; + struct pca954x *data; + int ret = -ENODEV; + + if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE)) + goto err; + + data = kzalloc(sizeof(struct pca954x), GFP_KERNEL); + if (!data) { + ret = -ENOMEM; + goto err; + } + + i2c_set_clientdata(client, data); + + /* Read the mux register at addr to verify + * that the mux is in fact present. + */ + if (i2c_smbus_read_byte(client) < 0) { + dev_warn(&client->dev, "probe failed\n"); + goto exit_free; + } + + data->type = id->driver_data; + data->last_chan = 0; /* force the first selection */ + + /* Now create an adapter for each channel */ + for (num = 0; num < chips[data->type].nchans; num++) { + force = 0; /* dynamic adap number */ + if (pdata) { + if (num < pdata->num_modes) + /* force static number */ + force = pdata->modes[num].adap_id; + else + /* discard unconfigured channels */ + break; + } + + data->virt_adaps[num] = + i2c_add_mux_adapter(adap, client, + force, num, pca954x_select_chan, + (pdata && pdata->modes[num].deselect_on_exit) + ? pca954x_deselect_mux : NULL); + + if (data->virt_adaps[num] == NULL) { + ret = -ENODEV; + dev_err(&client->dev, + "failed to register multiplexed adapter" + " %d as bus %d\n", num, force); + goto virt_reg_failed; + } + } + + dev_info(&client->dev, + "registered %d multiplexed busses for I2C %s %s\n", + num, chips[data->type].muxtype == pca954x_ismux + ? "mux" : "switch", client->name); + + return 0; + +virt_reg_failed: + for (num--; num >= 0; num--) + i2c_del_mux_adapter(data->virt_adaps[num]); +exit_free: + kfree(data); +err: + return ret; +} + +static int __devexit pca954x_remove(struct i2c_client *client) +{ + struct pca954x *data = i2c_get_clientdata(client); + const struct chip_desc *chip = &chips[data->type]; + int i, err; + + for (i = 0; i < chip->nchans; ++i) + if (data->virt_adaps[i]) { + err = i2c_del_mux_adapter(data->virt_adaps[i]); + if (err) + return err; + data->virt_adaps[i] = NULL; + } + + kfree(data); + return 0; +} + +static struct i2c_driver pca954x_driver = { + .driver = { + .name = "pca954x", + .owner = THIS_MODULE, + }, + .probe = pca954x_probe, + .remove = __devexit_p(pca954x_remove), + .id_table = pca954x_id, +}; + +static int __init pca954x_init(void) +{ + return i2c_add_driver(&pca954x_driver); +} + +static void __exit pca954x_exit(void) +{ + i2c_del_driver(&pca954x_driver); +} + +module_init(pca954x_init); +module_exit(pca954x_exit); + +MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>"); +MODULE_DESCRIPTION("PCA954x I2C mux/switch driver"); +MODULE_LICENSE("GPL v2"); |