diff options
Diffstat (limited to 'drivers/i2c/i2c-core.c')
| -rw-r--r-- | drivers/i2c/i2c-core.c | 1272 |
1 files changed, 1272 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c new file mode 100644 index 000000000000..9011627d7eb0 --- /dev/null +++ b/drivers/i2c/i2c-core.c @@ -0,0 +1,1272 @@ +/* i2c-core.c - a device driver for the iic-bus interface */ +/* ------------------------------------------------------------------------- */ +/* Copyright (C) 1995-99 Simon G. Vogl + + 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. */ +/* ------------------------------------------------------------------------- */ + +/* 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> */ + +#include <linux/config.h> +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/slab.h> +#include <linux/i2c.h> +#include <linux/init.h> +#include <linux/idr.h> +#include <linux/seq_file.h> +#include <asm/uaccess.h> + + +static LIST_HEAD(adapters); +static LIST_HEAD(drivers); +static DECLARE_MUTEX(core_lists); +static DEFINE_IDR(i2c_adapter_idr); + +/* match always succeeds, as we want the probe() to tell if we really accept this match */ +static int i2c_device_match(struct device *dev, struct device_driver *drv) +{ + return 1; +} + +static int i2c_bus_suspend(struct device * dev, pm_message_t state) +{ + int rc = 0; + + if (dev->driver && dev->driver->suspend) + rc = dev->driver->suspend(dev,state,0); + return rc; +} + +static int i2c_bus_resume(struct device * dev) +{ + int rc = 0; + + if (dev->driver && dev->driver->resume) + rc = dev->driver->resume(dev,0); + return rc; +} + +static struct bus_type i2c_bus_type = { + .name = "i2c", + .match = i2c_device_match, + .suspend = i2c_bus_suspend, + .resume = i2c_bus_resume, +}; + +static int i2c_device_probe(struct device *dev) +{ + return -ENODEV; +} + +static int i2c_device_remove(struct device *dev) +{ + return 0; +} + +static void i2c_adapter_dev_release(struct device *dev) +{ + struct i2c_adapter *adap = dev_to_i2c_adapter(dev); + complete(&adap->dev_released); +} + +static struct device_driver i2c_adapter_driver = { + .name = "i2c_adapter", + .bus = &i2c_bus_type, + .probe = i2c_device_probe, + .remove = i2c_device_remove, +}; + +static void i2c_adapter_class_dev_release(struct class_device *dev) +{ + struct i2c_adapter *adap = class_dev_to_i2c_adapter(dev); + complete(&adap->class_dev_released); +} + +static struct class i2c_adapter_class = { + .name = "i2c-adapter", + .release = &i2c_adapter_class_dev_release, +}; + +static ssize_t show_adapter_name(struct device *dev, char *buf) +{ + struct i2c_adapter *adap = dev_to_i2c_adapter(dev); + return sprintf(buf, "%s\n", adap->name); +} +static DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL); + + +static void i2c_client_release(struct device *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + complete(&client->released); +} + +static ssize_t show_client_name(struct device *dev, char *buf) +{ + struct i2c_client *client = to_i2c_client(dev); + return sprintf(buf, "%s\n", client->name); +} + +/* + * We can't use the DEVICE_ATTR() macro here as we want the same filename for a + * different type of a device. So beware if the DEVICE_ATTR() macro ever + * changes, this definition will also have to change. + */ +static struct device_attribute dev_attr_client_name = { + .attr = {.name = "name", .mode = S_IRUGO, .owner = THIS_MODULE }, + .show = &show_client_name, +}; + + +/* --------------------------------------------------- + * registering functions + * --------------------------------------------------- + */ + +/* ----- + * i2c_add_adapter is called from within the algorithm layer, + * when a new hw adapter registers. A new device is register to be + * available for clients. + */ +int i2c_add_adapter(struct i2c_adapter *adap) +{ + int id, res = 0; + struct list_head *item; + struct i2c_driver *driver; + + down(&core_lists); + + if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0) { + res = -ENOMEM; + goto out_unlock; + } + + res = idr_get_new(&i2c_adapter_idr, NULL, &id); + if (res < 0) { + if (res == -EAGAIN) + res = -ENOMEM; + goto out_unlock; + } + + adap->nr = id & MAX_ID_MASK; + init_MUTEX(&adap->bus_lock); + init_MUTEX(&adap->clist_lock); + list_add_tail(&adap->list,&adapters); + INIT_LIST_HEAD(&adap->clients); + + /* Add the adapter to the driver core. + * If the parent pointer is not set up, + * we add this adapter to the host bus. + */ + if (adap->dev.parent == NULL) + adap->dev.parent = &platform_bus; + sprintf(adap->dev.bus_id, "i2c-%d", adap->nr); + adap->dev.driver = &i2c_adapter_driver; + adap->dev.release = &i2c_adapter_dev_release; + device_register(&adap->dev); + device_create_file(&adap->dev, &dev_attr_name); + + /* Add this adapter to the i2c_adapter class */ + memset(&adap->class_dev, 0x00, sizeof(struct class_device)); + adap->class_dev.dev = &adap->dev; + adap->class_dev.class = &i2c_adapter_class; + strlcpy(adap->class_dev.class_id, adap->dev.bus_id, BUS_ID_SIZE); + class_device_register(&adap->class_dev); + + /* inform drivers of new adapters */ + list_for_each(item,&drivers) { + driver = list_entry(item, struct i2c_driver, list); + if (driver->flags & I2C_DF_NOTIFY) + /* We ignore the return code; if it fails, too bad */ + driver->attach_adapter(adap); + } + + dev_dbg(&adap->dev, "registered as adapter #%d\n", adap->nr); + +out_unlock: + up(&core_lists); + return res; +} + + +int i2c_del_adapter(struct i2c_adapter *adap) +{ + struct list_head *item, *_n; + struct i2c_adapter *adap_from_list; + struct i2c_driver *driver; + struct i2c_client *client; + int res = 0; + + down(&core_lists); + + /* First make sure that this adapter was ever added */ + list_for_each_entry(adap_from_list, &adapters, list) { + if (adap_from_list == adap) + break; + } + if (adap_from_list != adap) { + pr_debug("I2C: Attempting to delete an unregistered " + "adapter\n"); + res = -EINVAL; + goto out_unlock; + } + + list_for_each(item,&drivers) { + driver = list_entry(item, struct i2c_driver, list); + if (driver->detach_adapter) + if ((res = driver->detach_adapter(adap))) { + dev_warn(&adap->dev, "can't detach adapter " + "while detaching driver %s: driver not " + "detached!", driver->name); + goto out_unlock; + } + } + + /* detach any active clients. This must be done first, because + * it can fail; in which case we give upp. */ + list_for_each_safe(item, _n, &adap->clients) { + client = list_entry(item, struct i2c_client, list); + + /* detaching devices is unconditional of the set notify + * flag, as _all_ clients that reside on the adapter + * must be deleted, as this would cause invalid states. + */ + if ((res=client->driver->detach_client(client))) { + dev_err(&adap->dev, "adapter not " + "unregistered, because client at " + "address %02x can't be detached. ", + client->addr); + goto out_unlock; + } + } + + /* clean up the sysfs representation */ + init_completion(&adap->dev_released); + init_completion(&adap->class_dev_released); + class_device_unregister(&adap->class_dev); + device_remove_file(&adap->dev, &dev_attr_name); + device_unregister(&adap->dev); + list_del(&adap->list); + + /* wait for sysfs to drop all references */ + wait_for_completion(&adap->dev_released); + wait_for_completion(&adap->class_dev_released); + + /* free dynamically allocated bus id */ + idr_remove(&i2c_adapter_idr, adap->nr); + + dev_dbg(&adap->dev, "adapter unregistered\n"); + + out_unlock: + up(&core_lists); + return res; +} + + +/* ----- + * What follows is the "upwards" interface: commands for talking to clients, + * which implement the functions to access the physical information of the + * chips. + */ + +int i2c_add_driver(struct i2c_driver *driver) +{ + struct list_head *item; + struct i2c_adapter *adapter; + int res = 0; + + down(&core_lists); + + /* add the driver to the list of i2c drivers in the driver core */ + driver->driver.name = driver->name; + driver->driver.bus = &i2c_bus_type; + driver->driver.probe = i2c_device_probe; + driver->driver.remove = i2c_device_remove; + + res = driver_register(&driver->driver); + if (res) + goto out_unlock; + + list_add_tail(&driver->list,&drivers); + pr_debug("i2c-core: driver %s registered.\n", driver->name); + + /* now look for instances of driver on our adapters */ + if (driver->flags & I2C_DF_NOTIFY) { + list_for_each(item,&adapters) { + adapter = list_entry(item, struct i2c_adapter, list); + driver->attach_adapter(adapter); + } + } + + out_unlock: + up(&core_lists); + return res; +} + +int i2c_del_driver(struct i2c_driver *driver) +{ + struct list_head *item1, *item2, *_n; + struct i2c_client *client; + struct i2c_adapter *adap; + + int res = 0; + + down(&core_lists); + + /* Have a look at each adapter, if clients of this driver are still + * attached. If so, detach them to be able to kill the driver + * afterwards. + */ + pr_debug("i2c-core: unregister_driver - looking for clients.\n"); + /* removing clients does not depend on the notify flag, else + * invalid operation might (will!) result, when using stale client + * pointers. + */ + list_for_each(item1,&adapters) { + adap = list_entry(item1, struct i2c_adapter, list); + dev_dbg(&adap->dev, "examining adapter\n"); + if (driver->detach_adapter) { + if ((res = driver->detach_adapter(adap))) { + dev_warn(&adap->dev, "while unregistering " + "dummy driver %s, adapter could " + "not be detached properly; driver " + "not unloaded!",driver->name); + goto out_unlock; + } + } else { + list_for_each_safe(item2, _n, &adap->clients) { + client = list_entry(item2, struct i2c_client, list); + if (client->driver != driver) + continue; + pr_debug("i2c-core.o: detaching client %s:\n", client->name); + if ((res = driver->detach_client(client))) { + dev_err(&adap->dev, "while " + "unregistering driver " + "`%s', the client at " + "address %02x of " + "adapter could not " + "be detached; driver " + "not unloaded!", + driver->name, + client->addr); + goto out_unlock; + } + } + } + } + + driver_unregister(&driver->driver); + list_del(&driver->list); + pr_debug("i2c-core: driver unregistered: %s\n", driver->name); + + out_unlock: + up(&core_lists); + return 0; +} + +static int __i2c_check_addr(struct i2c_adapter *adapter, unsigned int addr) +{ + struct list_head *item; + struct i2c_client *client; + + list_for_each(item,&adapter->clients) { + client = list_entry(item, struct i2c_client, list); + if (client->addr == addr) + return -EBUSY; + } + return 0; +} + +int i2c_check_addr(struct i2c_adapter *adapter, int addr) +{ + int rval; + + down(&adapter->clist_lock); + rval = __i2c_check_addr(adapter, addr); + up(&adapter->clist_lock); + + return rval; +} + +int i2c_attach_client(struct i2c_client *client) +{ + struct i2c_adapter *adapter = client->adapter; + + down(&adapter->clist_lock); + if (__i2c_check_addr(client->adapter, client->addr)) { + up(&adapter->clist_lock); + return -EBUSY; + } + list_add_tail(&client->list,&adapter->clients); + up(&adapter->clist_lock); + + if (adapter->client_register) { + if (adapter->client_register(client)) { + dev_warn(&adapter->dev, "warning: client_register " + "seems to have failed for client %02x\n", + client->addr); + } + } + + dev_dbg(&adapter->dev, "client [%s] registered to adapter\n", + client->name); + + if (client->flags & I2C_CLIENT_ALLOW_USE) + client->usage_count = 0; + + client->dev.parent = &client->adapter->dev; + client->dev.driver = &client->driver->driver; + client->dev.bus = &i2c_bus_type; + client->dev.release = &i2c_client_release; + + snprintf(&client->dev.bus_id[0], sizeof(client->dev.bus_id), + "%d-%04x", i2c_adapter_id(adapter), client->addr); + pr_debug("registering %s\n", client->dev.bus_id); + device_register(&client->dev); + device_create_file(&client->dev, &dev_attr_client_name); + + return 0; +} + + +int i2c_detach_client(struct i2c_client *client) +{ + struct i2c_adapter *adapter = client->adapter; + int res = 0; + + if ((client->flags & I2C_CLIENT_ALLOW_USE) && (client->usage_count > 0)) + return -EBUSY; + + if (adapter->client_unregister) { + res = adapter->client_unregister(client); + if (res) { + dev_err(&client->dev, + "client_unregister [%s] failed, " + "client not detached", client->name); + goto out; + } + } + + down(&adapter->clist_lock); + list_del(&client->list); + init_completion(&client->released); + device_remove_file(&client->dev, &dev_attr_client_name); + device_unregister(&client->dev); + up(&adapter->clist_lock); + wait_for_completion(&client->released); + + out: + return res; +} + +static int i2c_inc_use_client(struct i2c_client *client) +{ + + if (!try_module_get(client->driver->owner)) + return -ENODEV; + if (!try_module_get(client->adapter->owner)) { + module_put(client->driver->owner); + return -ENODEV; + } + + return 0; +} + +static void i2c_dec_use_client(struct i2c_client *client) +{ + module_put(client->driver->owner); + module_put(client->adapter->owner); +} + +int i2c_use_client(struct i2c_client *client) +{ + int ret; + + ret = i2c_inc_use_client(client); + if (ret) + return ret; + + if (client->flags & I2C_CLIENT_ALLOW_USE) { + if (client->flags & I2C_CLIENT_ALLOW_MULTIPLE_USE) + client->usage_count++; + else if (client->usage_count > 0) + goto busy; + else + client->usage_count++; + } + + return 0; + busy: + i2c_dec_use_client(client); + return -EBUSY; +} + +int i2c_release_client(struct i2c_client *client) +{ + if(client->flags & I2C_CLIENT_ALLOW_USE) { + if(client->usage_count>0) + client->usage_count--; + else { + pr_debug("i2c-core: %s used one too many times\n", + __FUNCTION__); + return -EPERM; + } + } + + i2c_dec_use_client(client); + + return 0; +} + +void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg) +{ + struct list_head *item; + struct i2c_client *client; + + down(&adap->clist_lock); + list_for_each(item,&adap->clients) { + client = list_entry(item, struct i2c_client, list); + if (!try_module_get(client->driver->owner)) + continue; + if (NULL != client->driver->command) { + up(&adap->clist_lock); + client->driver->command(client,cmd,arg); + down(&adap->clist_lock); + } + module_put(client->driver->owner); + } + up(&adap->clist_lock); +} + +static int __init i2c_init(void) +{ + int retval; + + retval = bus_register(&i2c_bus_type); + if (retval) + return retval; + retval = driver_register(&i2c_adapter_driver); + if (retval) + return retval; + return class_register(&i2c_adapter_class); +} + +static void __exit i2c_exit(void) +{ + class_unregister(&i2c_adapter_class); + driver_unregister(&i2c_adapter_driver); + bus_unregister(&i2c_bus_type); +} + +subsys_initcall(i2c_init); +module_exit(i2c_exit); + +/* ---------------------------------------------------- + * the functional interface to the i2c busses. + * ---------------------------------------------------- + */ + +int i2c_transfer(struct i2c_adapter * adap, struct i2c_msg *msgs, int num) +{ + int ret; + + if (adap->algo->master_xfer) { +#ifdef DEBUG + for (ret = 0; ret < num; ret++) { + dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, " + "len=%d\n", ret, msgs[ret].flags & I2C_M_RD ? + 'R' : 'W', msgs[ret].addr, msgs[ret].len); + } +#endif + + down(&adap->bus_lock); + ret = adap->algo->master_xfer(adap,msgs,num); + up(&adap->bus_lock); + + return ret; + } else { + dev_dbg(&adap->dev, "I2C level transfers not supported\n"); + return -ENOSYS; + } +} + +int i2c_master_send(struct i2c_client *client,const char *buf ,int count) +{ + int ret; + struct i2c_adapter *adap=client->adapter; + struct i2c_msg msg; + + if (client->adapter->algo->master_xfer) { + msg.addr = client->addr; + msg.flags = client->flags & I2C_M_TEN; + msg.len = count; + msg.buf = (char *)buf; + + dev_dbg(&client->adapter->dev, "master_send: writing %d bytes.\n", + count); + + down(&adap->bus_lock); + ret = adap->algo->master_xfer(adap,&msg,1); + up(&adap->bus_lock); + + /* if everything went ok (i.e. 1 msg transmitted), return #bytes + * transmitted, else error code. + */ + return (ret == 1 )? count : ret; + } else { + dev_err(&client->adapter->dev, "I2C level transfers not supported\n"); + return -ENOSYS; + } +} + +int i2c_master_recv(struct i2c_client *client, char *buf ,int count) +{ + struct i2c_adapter *adap=client->adapter; + struct i2c_msg msg; + int ret; + if (client->adapter->algo->master_xfer) { + msg.addr = client->addr; + msg.flags = client->flags & I2C_M_TEN; + msg.flags |= I2C_M_RD; + msg.len = count; + msg.buf = buf; + + dev_dbg(&client->adapter->dev, "master_recv: reading %d bytes.\n", + count); + + down(&adap->bus_lock); + ret = adap->algo->master_xfer(adap,&msg,1); + up(&adap->bus_lock); + + dev_dbg(&client->adapter->dev, "master_recv: return:%d (count:%d, addr:0x%02x)\n", + ret, count, client->addr); + + /* if everything went ok (i.e. 1 msg transmitted), return #bytes + * transmitted, else error code. + */ + return (ret == 1 )? count : ret; + } else { + dev_err(&client->adapter->dev, "I2C level transfers not supported\n"); + return -ENOSYS; + } +} + + +int i2c_control(struct i2c_client *client, + unsigned int cmd, unsigned long arg) +{ + int ret = 0; + struct i2c_adapter *adap = client->adapter; + + dev_dbg(&client->adapter->dev, "i2c ioctl, cmd: 0x%x, arg: %#lx\n", cmd, arg); + switch (cmd) { + case I2C_RETRIES: + adap->retries = arg; + break; + case I2C_TIMEOUT: + adap->timeout = arg; + break; + default: + if (adap->algo->algo_control!=NULL) + ret = adap->algo->algo_control(adap,cmd,arg); + } + return ret; +} + +/* ---------------------------------------------------- + * the i2c address scanning function + * Will not work for 10-bit addresses! + * ---------------------------------------------------- + */ +int i2c_probe(struct i2c_adapter *adapter, + struct i2c_client_address_data *address_data, + int (*found_proc) (struct i2c_adapter *, int, int)) +{ + int addr,i,found,err; + int adap_id = i2c_adapter_id(adapter); + + /* Forget it if we can't probe using SMBUS_QUICK */ + if (! i2c_check_functionality(adapter,I2C_FUNC_SMBUS_QUICK)) + return -1; + + for (addr = 0x00; addr <= 0x7f; addr++) { + + /* Skip if already in use */ + if (i2c_check_addr(adapter,addr)) + continue; + + /* If it is in one of the force entries, we don't do any detection + at all */ + found = 0; + + for (i = 0; !found && (address_data->force[i] != I2C_CLIENT_END); i += 2) { + if (((adap_id == address_data->force[i]) || + (address_data->force[i] == ANY_I2C_BUS)) && + (addr == address_data->force[i+1])) { + dev_dbg(&adapter->dev, "found force parameter for adapter %d, addr %04x\n", + adap_id, addr); + if ((err = found_proc(adapter,addr,0))) + return err; + found = 1; + } + } + if (found) + continue; + + /* If this address is in one of the ignores, we can forget about + it right now */ + for (i = 0; + !found && (address_data->ignore[i] != I2C_CLIENT_END); + i += 2) { + if (((adap_id == address_data->ignore[i]) || + ((address_data->ignore[i] == ANY_I2C_BUS))) && + (addr == address_data->ignore[i+1])) { + dev_dbg(&adapter->dev, "found ignore parameter for adapter %d, " + "addr %04x\n", adap_id ,addr); + found = 1; + } + } + for (i = 0; + !found && (address_data->ignore_range[i] != I2C_CLIENT_END); + i += 3) { + if (((adap_id == address_data->ignore_range[i]) || + ((address_data->ignore_range[i]==ANY_I2C_BUS))) && + (addr >= address_data->ignore_range[i+1]) && + (addr <= address_data->ignore_range[i+2])) { + dev_dbg(&adapter->dev, "found ignore_range parameter for adapter %d, " + "addr %04x\n", adap_id,addr); + found = 1; + } + } + if (found) + continue; + + /* Now, we will do a detection, but only if it is in the normal or + probe entries */ + for (i = 0; + !found && (address_data->normal_i2c[i] != I2C_CLIENT_END); + i += 1) { + if (addr == address_data->normal_i2c[i]) { + found = 1; + dev_dbg(&adapter->dev, "found normal i2c entry for adapter %d, " + "addr %02x\n", adap_id, addr); + } + } + + for (i = 0; + !found && (address_data->normal_i2c_range[i] != I2C_CLIENT_END); + i += 2) { + if ((addr >= address_data->normal_i2c_range[i]) && + (addr <= address_data->normal_i2c_range[i+1])) { + found = 1; + dev_dbg(&adapter->dev, "found normal i2c_range entry for adapter %d, " + "addr %04x\n", adap_id,addr); + } + } + + for (i = 0; + !found && (address_data->probe[i] != I2C_CLIENT_END); + i += 2) { + if (((adap_id == address_data->probe[i]) || + ((address_data->probe[i] == ANY_I2C_BUS))) && + (addr == address_data->probe[i+1])) { + found = 1; + dev_dbg(&adapter->dev, "found probe parameter for adapter %d, " + "addr %04x\n", adap_id,addr); + } + } + for (i = 0; + !found && (address_data->probe_range[i] != I2C_CLIENT_END); + i += 3) { + if (((adap_id == address_data->probe_range[i]) || + (address_data->probe_range[i] == ANY_I2C_BUS)) && + (addr >= address_data->probe_range[i+1]) && + (addr <= address_data->probe_range[i+2])) { + found = 1; + dev_dbg(&adapter->dev, "found probe_range parameter for adapter %d, " + "addr %04x\n", adap_id,addr); + } + } + if (!found) + continue; + + /* OK, so we really should examine this address. First check + whether there is some client here at all! */ + if (i2c_smbus_xfer(adapter,addr,0,0,0,I2C_SMBUS_QUICK,NULL) >= 0) + if ((err = found_proc(adapter,addr,-1))) + return err; + } + return 0; +} + +/* + * return id number for a specific adapter + */ +int i2c_adapter_id(struct i2c_adapter *adap) +{ + return adap->nr; +} + +struct i2c_adapter* i2c_get_adapter(int id) +{ + struct list_head *item; + struct i2c_adapter *adapter; + + down(&core_lists); + list_for_each(item,&adapters) { + adapter = list_entry(item, struct i2c_adapter, list); + if (id == adapter->nr && + try_module_get(adapter->owner)) { + up(&core_lists); + return adapter; + } + } + up(&core_lists); + return NULL; +} + +void i2c_put_adapter(struct i2c_adapter *adap) +{ + module_put(adap->owner); +} + +/* The SMBus parts */ + +#define POLY (0x1070U << 3) +static u8 +crc8(u16 data) +{ + int i; + + for(i = 0; i < 8; i++) { + if (data & 0x8000) + data = data ^ POLY; + data = data << 1; + } + return (u8)(data >> 8); +} + +/* CRC over count bytes in the first array plus the bytes in the rest + array if it is non-null. rest[0] is the (length of rest) - 1 + and is included. */ +static u8 i2c_smbus_partial_pec(u8 crc, int count, u8 *first, u8 *rest) +{ + int i; + + for(i = 0; i < count; i++) + crc = crc8((crc ^ first[i]) << 8); + if(rest != NULL) + for(i = 0; i <= rest[0]; i++) + crc = crc8((crc ^ rest[i]) << 8); + return crc; +} + +static u8 i2c_smbus_pec(int count, u8 *first, u8 *rest) +{ + return i2c_smbus_partial_pec(0, count, first, rest); +} + +/* Returns new "size" (transaction type) + Note that we convert byte to byte_data and byte_data to word_data + rather than invent new xxx_PEC transactions. */ +static int i2c_smbus_add_pec(u16 addr, u8 command, int size, + union i2c_smbus_data *data) +{ + u8 buf[3]; + + buf[0] = addr << 1; + buf[1] = command; + switch(size) { + case I2C_SMBUS_BYTE: + data->byte = i2c_smbus_pec(2, buf, NULL); + size = I2C_SMBUS_BYTE_DATA; + break; + case I2C_SMBUS_BYTE_DATA: + buf[2] = data->byte; + data->word = buf[2] || + (i2c_smbus_pec(3, buf, NULL) << 8); + size = I2C_SMBUS_WORD_DATA; + break; + case I2C_SMBUS_WORD_DATA: + /* unsupported */ + break; + case I2C_SMBUS_BLOCK_DATA: + data->block[data->block[0] + 1] = + i2c_smbus_pec(2, buf, data->block); + size = I2C_SMBUS_BLOCK_DATA_PEC; + break; + } + return size; +} + +static int i2c_smbus_check_pec(u16 addr, u8 command, int size, u8 partial, + union i2c_smbus_data *data) +{ + u8 buf[3], rpec, cpec; + + buf[1] = command; + switch(size) { + case I2C_SMBUS_BYTE_DATA: + buf[0] = (addr << 1) | 1; + cpec = i2c_smbus_pec(2, buf, NULL); + rpec = data->byte; + break; + case I2C_SMBUS_WORD_DATA: + buf[0] = (addr << 1) | 1; + buf[2] = data->word & 0xff; + cpec = i2c_smbus_pec(3, buf, NULL); + rpec = data->word >> 8; + break; + case I2C_SMBUS_WORD_DATA_PEC: + /* unsupported */ + cpec = rpec = 0; + break; + case I2C_SMBUS_PROC_CALL_PEC: + /* unsupported */ + cpec = rpec = 0; + break; + case I2C_SMBUS_BLOCK_DATA_PEC: + buf[0] = (addr << 1); + buf[2] = (addr << 1) | 1; + cpec = i2c_smbus_pec(3, buf, data->block); + rpec = data->block[data->block[0] + 1]; + break; + case I2C_SMBUS_BLOCK_PROC_CALL_PEC: + buf[0] = (addr << 1) | 1; + rpec = i2c_smbus_partial_pec(partial, 1, + buf, data->block); + cpec = data->block[data->block[0] + 1]; + break; + default: + cpec = rpec = 0; + break; + } + if (rpec != cpec) { + pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n", + rpec, cpec); + return -1; + } + return 0; +} + +s32 i2c_smbus_write_quick(struct i2c_client *client, u8 value) +{ + return i2c_smbus_xfer(client->adapter,client->addr,client->flags, + value,0,I2C_SMBUS_QUICK,NULL); +} + +s32 i2c_smbus_read_byte(struct i2c_client *client) +{ + union i2c_smbus_data data; + if (i2c_smbus_xfer(client->adapter,client->addr,client->flags, + I2C_SMBUS_READ,0,I2C_SMBUS_BYTE, &data)) + return -1; + else + return 0x0FF & data.byte; +} + +s32 i2c_smbus_write_byte(struct i2c_client *client, u8 value) +{ + union i2c_smbus_data data; /* only for PEC */ + return i2c_smbus_xfer(client->adapter,client->addr,client->flags, + I2C_SMBUS_WRITE,value, I2C_SMBUS_BYTE,&data); +} + +s32 i2c_smbus_read_byte_data(struct i2c_client *client, u8 command) +{ + union i2c_smbus_data data; + if (i2c_smbus_xfer(client->adapter,client->addr,client->flags, + I2C_SMBUS_READ,command, I2C_SMBUS_BYTE_DATA,&data)) + return -1; + else + return 0x0FF & data.byte; +} + +s32 i2c_smbus_write_byte_data(struct i2c_client *client, u8 command, u8 value) +{ + union i2c_smbus_data data; + data.byte = value; + return i2c_smbus_xfer(client->adapter,client->addr,client->flags, + I2C_SMBUS_WRITE,command, + I2C_SMBUS_BYTE_DATA,&data); +} + +s32 i2c_smbus_read_word_data(struct i2c_client *client, u8 command) +{ + union i2c_smbus_data data; + if (i2c_smbus_xfer(client->adapter,client->addr,client->flags, + I2C_SMBUS_READ,command, I2C_SMBUS_WORD_DATA, &data)) + return -1; + else + return 0x0FFFF & data.word; +} + +s32 i2c_smbus_write_word_data(struct i2c_client *client, u8 command, u16 value) +{ + union i2c_smbus_data data; + data.word = value; + return i2c_smbus_xfer(client->adapter,client->addr,client->flags, + I2C_SMBUS_WRITE,command, + I2C_SMBUS_WORD_DATA,&data); +} + +s32 i2c_smbus_write_block_data(struct i2c_client *client, u8 command, + u8 length, u8 *values) +{ + union i2c_smbus_data data; + int i; + if (length > I2C_SMBUS_BLOCK_MAX) + length = I2C_SMBUS_BLOCK_MAX; + for (i = 1; i <= length; i++) + data.block[i] = values[i-1]; + data.block[0] = length; + return i2c_smbus_xfer(client->adapter,client->addr,client->flags, + I2C_SMBUS_WRITE,command, + I2C_SMBUS_BLOCK_DATA,&data); +} + +/* Returns the number of read bytes */ +s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client, u8 command, u8 *values) +{ + union i2c_smbus_data data; + int i; + if (i2c_smbus_xfer(client->adapter,client->addr,client->flags, + I2C_SMBUS_READ,command, + I2C_SMBUS_I2C_BLOCK_DATA,&data)) + return -1; + else { + for (i = 1; i <= data.block[0]; i++) + values[i-1] = data.block[i]; + return data.block[0]; + } +} + +/* Simulate a SMBus command using the i2c protocol + No checking of parameters is done! */ +static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr, + unsigned short flags, + char read_write, u8 command, int size, + union i2c_smbus_data * data) +{ + /* So we need to generate a series of msgs. In the case of writing, we + need to use only one message; when reading, we need two. We initialize + most things with sane defaults, to keep the code below somewhat + simpler. */ + unsigned char msgbuf0[34]; + unsigned char msgbuf1[34]; + int num = read_write == I2C_SMBUS_READ?2:1; + struct i2c_msg msg[2] = { { addr, flags, 1, msgbuf0 }, + { addr, flags | I2C_M_RD, 0, msgbuf1 } + }; + int i; + + msgbuf0[0] = command; + switch(size) { + case I2C_SMBUS_QUICK: + msg[0].len = 0; + /* Special case: The read/write field is used as data */ + msg[0].flags = flags | (read_write==I2C_SMBUS_READ)?I2C_M_RD:0; + num = 1; + break; + case I2C_SMBUS_BYTE: + if (read_write == I2C_SMBUS_READ) { + /* Special case: only a read! */ + msg[0].flags = I2C_M_RD | flags; + num = 1; + } + break; + case I2C_SMBUS_BYTE_DATA: + if (read_write == I2C_SMBUS_READ) + msg[1].len = 1; + else { + msg[0].len = 2; + msgbuf0[1] = data->byte; + } + break; + case I2C_SMBUS_WORD_DATA: + if (read_write == I2C_SMBUS_READ) + msg[1].len = 2; + else { + msg[0].len=3; + msgbuf0[1] = data->word & 0xff; + msgbuf0[2] = (data->word >> 8) & 0xff; + } + break; + case I2C_SMBUS_PROC_CALL: + num = 2; /* Special case */ + read_write = I2C_SMBUS_READ; + msg[0].len = 3; + msg[1].len = 2; + msgbuf0[1] = data->word & 0xff; + msgbuf0[2] = (data->word >> 8) & 0xff; + break; + case I2C_SMBUS_BLOCK_DATA: + case I2C_SMBUS_BLOCK_DATA_PEC: + if (read_write == I2C_SMBUS_READ) { + dev_err(&adapter->dev, "Block read not supported " + "under I2C emulation!\n"); + return -1; + } else { + msg[0].len = data->block[0] + 2; + if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) { + dev_err(&adapter->dev, "smbus_access called with " + "invalid block write size (%d)\n", + data->block[0]); + return -1; + } + if(size == I2C_SMBUS_BLOCK_DATA_PEC) + (msg[0].len)++; + for (i = 1; i <= msg[0].len; i++) + msgbuf0[i] = data->block[i-1]; + } + break; + case I2C_SMBUS_BLOCK_PROC_CALL: + case I2C_SMBUS_BLOCK_PROC_CALL_PEC: + dev_dbg(&adapter->dev, "Block process call not supported " + "under I2C emulation!\n"); + return -1; + case I2C_SMBUS_I2C_BLOCK_DATA: + if (read_write == I2C_SMBUS_READ) { + msg[1].len = I2C_SMBUS_I2C_BLOCK_MAX; + } else { + msg[0].len = data->block[0] + 1; + if (msg[0].len > I2C_SMBUS_I2C_BLOCK_MAX + 1) { + dev_err(&adapter->dev, "i2c_smbus_xfer_emulated called with " + "invalid block write size (%d)\n", + data->block[0]); + return -1; + } + for (i = 1; i <= data->block[0]; i++) + msgbuf0[i] = data->block[i]; + } + break; + default: + dev_err(&adapter->dev, "smbus_access called with invalid size (%d)\n", + size); + return -1; + } + + if (i2c_transfer(adapter, msg, num) < 0) + return -1; + + if (read_write == I2C_SMBUS_READ) + switch(size) { + case I2C_SMBUS_BYTE: + data->byte = msgbuf0[0]; + break; + case I2C_SMBUS_BYTE_DATA: + data->byte = msgbuf1[0]; + break; + case I2C_SMBUS_WORD_DATA: + case I2C_SMBUS_PROC_CALL: + data->word = msgbuf1[0] | (msgbuf1[1] << 8); + break; + case I2C_SMBUS_I2C_BLOCK_DATA: + /* fixed at 32 for now */ + data->block[0] = I2C_SMBUS_I2C_BLOCK_MAX; + for (i = 0; i < I2C_SMBUS_I2C_BLOCK_MAX; i++) + data->block[i+1] = msgbuf1[i]; + break; + } + return 0; +} + + +s32 i2c_smbus_xfer(struct i2c_adapter * adapter, u16 addr, unsigned short flags, + char read_write, u8 command, int size, + union i2c_smbus_data * data) +{ + s32 res; + int swpec = 0; + u8 partial = 0; + + flags &= I2C_M_TEN | I2C_CLIENT_PEC; + if((flags & I2C_CLIENT_PEC) && + !(i2c_check_functionality(adapter, I2C_FUNC_SMBUS_HWPEC_CALC))) { + swpec = 1; + if(read_write == I2C_SMBUS_READ && + size == I2C_SMBUS_BLOCK_DATA) + size = I2C_SMBUS_BLOCK_DATA_PEC; + else if(size == I2C_SMBUS_PROC_CALL) + size = I2C_SMBUS_PROC_CALL_PEC; + else if(size == I2C_SMBUS_BLOCK_PROC_CALL) { + i2c_smbus_add_pec(addr, command, + I2C_SMBUS_BLOCK_DATA, data); + partial = data->block[data->block[0] + 1]; + size = I2C_SMBUS_BLOCK_PROC_CALL_PEC; + } else if(read_write == I2C_SMBUS_WRITE && + size != I2C_SMBUS_QUICK && + size != I2C_SMBUS_I2C_BLOCK_DATA) + size = i2c_smbus_add_pec(addr, command, size, data); + } + + if (adapter->algo->smbus_xfer) { + down(&adapter->bus_lock); + res = adapter->algo->smbus_xfer(adapter,addr,flags,read_write, + command,size,data); + up(&adapter->bus_lock); + } else + res = i2c_smbus_xfer_emulated(adapter,addr,flags,read_write, + command,size,data); + + if(res >= 0 && swpec && + size != I2C_SMBUS_QUICK && size != I2C_SMBUS_I2C_BLOCK_DATA && + (read_write == I2C_SMBUS_READ || size == I2C_SMBUS_PROC_CALL_PEC || + size == I2C_SMBUS_BLOCK_PROC_CALL_PEC)) { + if(i2c_smbus_check_pec(addr, command, size, partial, data)) + return -1; + } + return res; +} + + +EXPORT_SYMBOL(i2c_add_adapter); +EXPORT_SYMBOL(i2c_del_adapter); +EXPORT_SYMBOL(i2c_add_driver); +EXPORT_SYMBOL(i2c_del_driver); +EXPORT_SYMBOL(i2c_attach_client); +EXPORT_SYMBOL(i2c_detach_client); +EXPORT_SYMBOL(i2c_use_client); +EXPORT_SYMBOL(i2c_release_client); +EXPORT_SYMBOL(i2c_clients_command); +EXPORT_SYMBOL(i2c_check_addr); + +EXPORT_SYMBOL(i2c_master_send); +EXPORT_SYMBOL(i2c_master_recv); +EXPORT_SYMBOL(i2c_control); +EXPORT_SYMBOL(i2c_transfer); +EXPORT_SYMBOL(i2c_adapter_id); +EXPORT_SYMBOL(i2c_get_adapter); +EXPORT_SYMBOL(i2c_put_adapter); +EXPORT_SYMBOL(i2c_probe); + +EXPORT_SYMBOL(i2c_smbus_xfer); +EXPORT_SYMBOL(i2c_smbus_write_quick); +EXPORT_SYMBOL(i2c_smbus_read_byte); +EXPORT_SYMBOL(i2c_smbus_write_byte); +EXPORT_SYMBOL(i2c_smbus_read_byte_data); +EXPORT_SYMBOL(i2c_smbus_write_byte_data); +EXPORT_SYMBOL(i2c_smbus_read_word_data); +EXPORT_SYMBOL(i2c_smbus_write_word_data); +EXPORT_SYMBOL(i2c_smbus_write_block_data); +EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data); + +MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); +MODULE_DESCRIPTION("I2C-Bus main module"); +MODULE_LICENSE("GPL"); |