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Diffstat (limited to 'kernel/include/linux/i2c.h')
| -rw-r--r-- | kernel/include/linux/i2c.h | 654 |
1 files changed, 654 insertions, 0 deletions
diff --git a/kernel/include/linux/i2c.h b/kernel/include/linux/i2c.h new file mode 100644 index 000000000..e83a738a3 --- /dev/null +++ b/kernel/include/linux/i2c.h @@ -0,0 +1,654 @@ +/* ------------------------------------------------------------------------- */ +/* */ +/* i2c.h - definitions for the i2c-bus interface */ +/* */ +/* ------------------------------------------------------------------------- */ +/* Copyright (C) 1995-2000 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., 51 Franklin Street, Fifth Floor, Boston, + MA 02110-1301 USA. */ +/* ------------------------------------------------------------------------- */ + +/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and + Frodo Looijaard <frodol@dds.nl> */ +#ifndef _LINUX_I2C_H +#define _LINUX_I2C_H + +#include <linux/mod_devicetable.h> +#include <linux/device.h> /* for struct device */ +#include <linux/sched.h> /* for completion */ +#include <linux/mutex.h> +#include <linux/of.h> /* for struct device_node */ +#include <linux/swab.h> /* for swab16 */ +#include <uapi/linux/i2c.h> + +extern struct bus_type i2c_bus_type; +extern struct device_type i2c_adapter_type; + +/* --- General options ------------------------------------------------ */ + +struct i2c_msg; +struct i2c_algorithm; +struct i2c_adapter; +struct i2c_client; +struct i2c_driver; +union i2c_smbus_data; +struct i2c_board_info; +enum i2c_slave_event; +typedef int (*i2c_slave_cb_t)(struct i2c_client *, enum i2c_slave_event, u8 *); + +struct module; + +#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE) +/* + * The master routines are the ones normally used to transmit data to devices + * on a bus (or read from them). Apart from two basic transfer functions to + * transmit one message at a time, a more complex version can be used to + * transmit an arbitrary number of messages without interruption. + * @count must be be less than 64k since msg.len is u16. + */ +extern int i2c_master_send(const struct i2c_client *client, const char *buf, + int count); +extern int i2c_master_recv(const struct i2c_client *client, char *buf, + int count); + +/* Transfer num messages. + */ +extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, + int num); +/* Unlocked flavor */ +extern int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, + int num); + +/* This is the very generalized SMBus access routine. You probably do not + want to use this, though; one of the functions below may be much easier, + and probably just as fast. + Note that we use i2c_adapter here, because you do not need a specific + smbus adapter to call this function. */ +extern 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); + +/* Now follow the 'nice' access routines. These also document the calling + conventions of i2c_smbus_xfer. */ + +extern s32 i2c_smbus_read_byte(const struct i2c_client *client); +extern s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value); +extern s32 i2c_smbus_read_byte_data(const struct i2c_client *client, + u8 command); +extern s32 i2c_smbus_write_byte_data(const struct i2c_client *client, + u8 command, u8 value); +extern s32 i2c_smbus_read_word_data(const struct i2c_client *client, + u8 command); +extern s32 i2c_smbus_write_word_data(const struct i2c_client *client, + u8 command, u16 value); + +static inline s32 +i2c_smbus_read_word_swapped(const struct i2c_client *client, u8 command) +{ + s32 value = i2c_smbus_read_word_data(client, command); + + return (value < 0) ? value : swab16(value); +} + +static inline s32 +i2c_smbus_write_word_swapped(const struct i2c_client *client, + u8 command, u16 value) +{ + return i2c_smbus_write_word_data(client, command, swab16(value)); +} + +/* Returns the number of read bytes */ +extern s32 i2c_smbus_read_block_data(const struct i2c_client *client, + u8 command, u8 *values); +extern s32 i2c_smbus_write_block_data(const struct i2c_client *client, + u8 command, u8 length, const u8 *values); +/* Returns the number of read bytes */ +extern s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, + u8 command, u8 length, u8 *values); +extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, + u8 command, u8 length, + const u8 *values); +#endif /* I2C */ + +/** + * struct i2c_driver - represent an I2C device driver + * @class: What kind of i2c device we instantiate (for detect) + * @attach_adapter: Callback for bus addition (deprecated) + * @probe: Callback for device binding + * @remove: Callback for device unbinding + * @shutdown: Callback for device shutdown + * @alert: Alert callback, for example for the SMBus alert protocol + * @command: Callback for bus-wide signaling (optional) + * @driver: Device driver model driver + * @id_table: List of I2C devices supported by this driver + * @detect: Callback for device detection + * @address_list: The I2C addresses to probe (for detect) + * @clients: List of detected clients we created (for i2c-core use only) + * + * The driver.owner field should be set to the module owner of this driver. + * The driver.name field should be set to the name of this driver. + * + * For automatic device detection, both @detect and @address_list must + * be defined. @class should also be set, otherwise only devices forced + * with module parameters will be created. The detect function must + * fill at least the name field of the i2c_board_info structure it is + * handed upon successful detection, and possibly also the flags field. + * + * If @detect is missing, the driver will still work fine for enumerated + * devices. Detected devices simply won't be supported. This is expected + * for the many I2C/SMBus devices which can't be detected reliably, and + * the ones which can always be enumerated in practice. + * + * The i2c_client structure which is handed to the @detect callback is + * not a real i2c_client. It is initialized just enough so that you can + * call i2c_smbus_read_byte_data and friends on it. Don't do anything + * else with it. In particular, calling dev_dbg and friends on it is + * not allowed. + */ +struct i2c_driver { + unsigned int class; + + /* Notifies the driver that a new bus has appeared. You should avoid + * using this, it will be removed in a near future. + */ + int (*attach_adapter)(struct i2c_adapter *) __deprecated; + + /* Standard driver model interfaces */ + int (*probe)(struct i2c_client *, const struct i2c_device_id *); + int (*remove)(struct i2c_client *); + + /* driver model interfaces that don't relate to enumeration */ + void (*shutdown)(struct i2c_client *); + + /* Alert callback, for example for the SMBus alert protocol. + * The format and meaning of the data value depends on the protocol. + * For the SMBus alert protocol, there is a single bit of data passed + * as the alert response's low bit ("event flag"). + */ + void (*alert)(struct i2c_client *, unsigned int data); + + /* a ioctl like command that can be used to perform specific functions + * with the device. + */ + int (*command)(struct i2c_client *client, unsigned int cmd, void *arg); + + struct device_driver driver; + const struct i2c_device_id *id_table; + + /* Device detection callback for automatic device creation */ + int (*detect)(struct i2c_client *, struct i2c_board_info *); + const unsigned short *address_list; + struct list_head clients; +}; +#define to_i2c_driver(d) container_of(d, struct i2c_driver, driver) + +/** + * struct i2c_client - represent an I2C slave device + * @flags: I2C_CLIENT_TEN indicates the device uses a ten bit chip address; + * I2C_CLIENT_PEC indicates it uses SMBus Packet Error Checking + * @addr: Address used on the I2C bus connected to the parent adapter. + * @name: Indicates the type of the device, usually a chip name that's + * generic enough to hide second-sourcing and compatible revisions. + * @adapter: manages the bus segment hosting this I2C device + * @dev: Driver model device node for the slave. + * @irq: indicates the IRQ generated by this device (if any) + * @detected: member of an i2c_driver.clients list or i2c-core's + * userspace_devices list + * @slave_cb: Callback when I2C slave mode of an adapter is used. The adapter + * calls it to pass on slave events to the slave driver. + * + * An i2c_client identifies a single device (i.e. chip) connected to an + * i2c bus. The behaviour exposed to Linux is defined by the driver + * managing the device. + */ +struct i2c_client { + unsigned short flags; /* div., see below */ + unsigned short addr; /* chip address - NOTE: 7bit */ + /* addresses are stored in the */ + /* _LOWER_ 7 bits */ + char name[I2C_NAME_SIZE]; + struct i2c_adapter *adapter; /* the adapter we sit on */ + struct device dev; /* the device structure */ + int irq; /* irq issued by device */ + struct list_head detected; +#if IS_ENABLED(CONFIG_I2C_SLAVE) + i2c_slave_cb_t slave_cb; /* callback for slave mode */ +#endif +}; +#define to_i2c_client(d) container_of(d, struct i2c_client, dev) + +extern struct i2c_client *i2c_verify_client(struct device *dev); +extern struct i2c_adapter *i2c_verify_adapter(struct device *dev); + +static inline struct i2c_client *kobj_to_i2c_client(struct kobject *kobj) +{ + struct device * const dev = container_of(kobj, struct device, kobj); + return to_i2c_client(dev); +} + +static inline void *i2c_get_clientdata(const struct i2c_client *dev) +{ + return dev_get_drvdata(&dev->dev); +} + +static inline void i2c_set_clientdata(struct i2c_client *dev, void *data) +{ + dev_set_drvdata(&dev->dev, data); +} + +/* I2C slave support */ + +#if IS_ENABLED(CONFIG_I2C_SLAVE) +enum i2c_slave_event { + I2C_SLAVE_READ_REQUESTED, + I2C_SLAVE_WRITE_REQUESTED, + I2C_SLAVE_READ_PROCESSED, + I2C_SLAVE_WRITE_RECEIVED, + I2C_SLAVE_STOP, +}; + +extern int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb); +extern int i2c_slave_unregister(struct i2c_client *client); + +static inline int i2c_slave_event(struct i2c_client *client, + enum i2c_slave_event event, u8 *val) +{ + return client->slave_cb(client, event, val); +} +#endif + +/** + * struct i2c_board_info - template for device creation + * @type: chip type, to initialize i2c_client.name + * @flags: to initialize i2c_client.flags + * @addr: stored in i2c_client.addr + * @platform_data: stored in i2c_client.dev.platform_data + * @archdata: copied into i2c_client.dev.archdata + * @of_node: pointer to OpenFirmware device node + * @fwnode: device node supplied by the platform firmware + * @irq: stored in i2c_client.irq + * + * I2C doesn't actually support hardware probing, although controllers and + * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's + * a device at a given address. Drivers commonly need more information than + * that, such as chip type, configuration, associated IRQ, and so on. + * + * i2c_board_info is used to build tables of information listing I2C devices + * that are present. This information is used to grow the driver model tree. + * For mainboards this is done statically using i2c_register_board_info(); + * bus numbers identify adapters that aren't yet available. For add-on boards, + * i2c_new_device() does this dynamically with the adapter already known. + */ +struct i2c_board_info { + char type[I2C_NAME_SIZE]; + unsigned short flags; + unsigned short addr; + void *platform_data; + struct dev_archdata *archdata; + struct device_node *of_node; + struct fwnode_handle *fwnode; + int irq; +}; + +/** + * I2C_BOARD_INFO - macro used to list an i2c device and its address + * @dev_type: identifies the device type + * @dev_addr: the device's address on the bus. + * + * This macro initializes essential fields of a struct i2c_board_info, + * declaring what has been provided on a particular board. Optional + * fields (such as associated irq, or device-specific platform_data) + * are provided using conventional syntax. + */ +#define I2C_BOARD_INFO(dev_type, dev_addr) \ + .type = dev_type, .addr = (dev_addr) + + +#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE) +/* Add-on boards should register/unregister their devices; e.g. a board + * with integrated I2C, a config eeprom, sensors, and a codec that's + * used in conjunction with the primary hardware. + */ +extern struct i2c_client * +i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info); + +/* If you don't know the exact address of an I2C device, use this variant + * instead, which can probe for device presence in a list of possible + * addresses. The "probe" callback function is optional. If it is provided, + * it must return 1 on successful probe, 0 otherwise. If it is not provided, + * a default probing method is used. + */ +extern struct i2c_client * +i2c_new_probed_device(struct i2c_adapter *adap, + struct i2c_board_info *info, + unsigned short const *addr_list, + int (*probe)(struct i2c_adapter *, unsigned short addr)); + +/* Common custom probe functions */ +extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr); + +/* For devices that use several addresses, use i2c_new_dummy() to make + * client handles for the extra addresses. + */ +extern struct i2c_client * +i2c_new_dummy(struct i2c_adapter *adap, u16 address); + +extern void i2c_unregister_device(struct i2c_client *); +#endif /* I2C */ + +/* Mainboard arch_initcall() code should register all its I2C devices. + * This is done at arch_initcall time, before declaring any i2c adapters. + * Modules for add-on boards must use other calls. + */ +#ifdef CONFIG_I2C_BOARDINFO +extern int +i2c_register_board_info(int busnum, struct i2c_board_info const *info, + unsigned n); +#else +static inline int +i2c_register_board_info(int busnum, struct i2c_board_info const *info, + unsigned n) +{ + return 0; +} +#endif /* I2C_BOARDINFO */ + +/** + * struct i2c_algorithm - represent I2C transfer method + * @master_xfer: Issue a set of i2c transactions to the given I2C adapter + * defined by the msgs array, with num messages available to transfer via + * the adapter specified by adap. + * @smbus_xfer: Issue smbus transactions to the given I2C adapter. If this + * is not present, then the bus layer will try and convert the SMBus calls + * into I2C transfers instead. + * @functionality: Return the flags that this algorithm/adapter pair supports + * from the I2C_FUNC_* flags. + * @reg_slave: Register given client to I2C slave mode of this adapter + * @unreg_slave: Unregister given client from I2C slave mode of this adapter + * + * The following structs are for those who like to implement new bus drivers: + * i2c_algorithm is the interface to a class of hardware solutions which can + * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584 + * to name two of the most common. + * + * The return codes from the @master_xfer field should indicate the type of + * error code that occurred during the transfer, as documented in the kernel + * Documentation file Documentation/i2c/fault-codes. + */ +struct i2c_algorithm { + /* If an adapter algorithm can't do I2C-level access, set master_xfer + to NULL. If an adapter algorithm can do SMBus access, set + smbus_xfer. If set to NULL, the SMBus protocol is simulated + using common I2C messages */ + /* master_xfer should return the number of messages successfully + processed, or a negative value on error */ + int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs, + int num); + int (*smbus_xfer) (struct i2c_adapter *adap, u16 addr, + unsigned short flags, char read_write, + u8 command, int size, union i2c_smbus_data *data); + + /* To determine what the adapter supports */ + u32 (*functionality) (struct i2c_adapter *); + +#if IS_ENABLED(CONFIG_I2C_SLAVE) + int (*reg_slave)(struct i2c_client *client); + int (*unreg_slave)(struct i2c_client *client); +#endif +}; + +/** + * struct i2c_bus_recovery_info - I2C bus recovery information + * @recover_bus: Recover routine. Either pass driver's recover_bus() routine, or + * i2c_generic_scl_recovery() or i2c_generic_gpio_recovery(). + * @get_scl: This gets current value of SCL line. Mandatory for generic SCL + * recovery. Used internally for generic GPIO recovery. + * @set_scl: This sets/clears SCL line. Mandatory for generic SCL recovery. Used + * internally for generic GPIO recovery. + * @get_sda: This gets current value of SDA line. Optional for generic SCL + * recovery. Used internally, if sda_gpio is a valid GPIO, for generic GPIO + * recovery. + * @prepare_recovery: This will be called before starting recovery. Platform may + * configure padmux here for SDA/SCL line or something else they want. + * @unprepare_recovery: This will be called after completing recovery. Platform + * may configure padmux here for SDA/SCL line or something else they want. + * @scl_gpio: gpio number of the SCL line. Only required for GPIO recovery. + * @sda_gpio: gpio number of the SDA line. Only required for GPIO recovery. + */ +struct i2c_bus_recovery_info { + int (*recover_bus)(struct i2c_adapter *); + + int (*get_scl)(struct i2c_adapter *); + void (*set_scl)(struct i2c_adapter *, int val); + int (*get_sda)(struct i2c_adapter *); + + void (*prepare_recovery)(struct i2c_adapter *); + void (*unprepare_recovery)(struct i2c_adapter *); + + /* gpio recovery */ + int scl_gpio; + int sda_gpio; +}; + +int i2c_recover_bus(struct i2c_adapter *adap); + +/* Generic recovery routines */ +int i2c_generic_gpio_recovery(struct i2c_adapter *adap); +int i2c_generic_scl_recovery(struct i2c_adapter *adap); + +/** + * struct i2c_adapter_quirks - describe flaws of an i2c adapter + * @flags: see I2C_AQ_* for possible flags and read below + * @max_num_msgs: maximum number of messages per transfer + * @max_write_len: maximum length of a write message + * @max_read_len: maximum length of a read message + * @max_comb_1st_msg_len: maximum length of the first msg in a combined message + * @max_comb_2nd_msg_len: maximum length of the second msg in a combined message + * + * Note about combined messages: Some I2C controllers can only send one message + * per transfer, plus something called combined message or write-then-read. + * This is (usually) a small write message followed by a read message and + * barely enough to access register based devices like EEPROMs. There is a flag + * to support this mode. It implies max_num_msg = 2 and does the length checks + * with max_comb_*_len because combined message mode usually has its own + * limitations. Because of HW implementations, some controllers can actually do + * write-then-anything or other variants. To support that, write-then-read has + * been broken out into smaller bits like write-first and read-second which can + * be combined as needed. + */ + +struct i2c_adapter_quirks { + u64 flags; + int max_num_msgs; + u16 max_write_len; + u16 max_read_len; + u16 max_comb_1st_msg_len; + u16 max_comb_2nd_msg_len; +}; + +/* enforce max_num_msgs = 2 and use max_comb_*_len for length checks */ +#define I2C_AQ_COMB BIT(0) +/* first combined message must be write */ +#define I2C_AQ_COMB_WRITE_FIRST BIT(1) +/* second combined message must be read */ +#define I2C_AQ_COMB_READ_SECOND BIT(2) +/* both combined messages must have the same target address */ +#define I2C_AQ_COMB_SAME_ADDR BIT(3) +/* convenience macro for typical write-then read case */ +#define I2C_AQ_COMB_WRITE_THEN_READ (I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | \ + I2C_AQ_COMB_READ_SECOND | I2C_AQ_COMB_SAME_ADDR) + +/* + * i2c_adapter is the structure used to identify a physical i2c bus along + * with the access algorithms necessary to access it. + */ +struct i2c_adapter { + struct module *owner; + unsigned int class; /* classes to allow probing for */ + const struct i2c_algorithm *algo; /* the algorithm to access the bus */ + void *algo_data; + + /* data fields that are valid for all devices */ + struct rt_mutex bus_lock; + + int timeout; /* in jiffies */ + int retries; + struct device dev; /* the adapter device */ + + int nr; + char name[48]; + struct completion dev_released; + + struct mutex userspace_clients_lock; + struct list_head userspace_clients; + + struct i2c_bus_recovery_info *bus_recovery_info; + const struct i2c_adapter_quirks *quirks; +}; +#define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev) + +static inline void *i2c_get_adapdata(const struct i2c_adapter *dev) +{ + return dev_get_drvdata(&dev->dev); +} + +static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data) +{ + dev_set_drvdata(&dev->dev, data); +} + +static inline struct i2c_adapter * +i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter) +{ +#if IS_ENABLED(CONFIG_I2C_MUX) + struct device *parent = adapter->dev.parent; + + if (parent != NULL && parent->type == &i2c_adapter_type) + return to_i2c_adapter(parent); + else +#endif + return NULL; +} + +int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *)); + +/* Adapter locking functions, exported for shared pin cases */ +void i2c_lock_adapter(struct i2c_adapter *); +void i2c_unlock_adapter(struct i2c_adapter *); + +/*flags for the client struct: */ +#define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */ +#define I2C_CLIENT_TEN 0x10 /* we have a ten bit chip address */ + /* Must equal I2C_M_TEN below */ +#define I2C_CLIENT_WAKE 0x80 /* for board_info; true iff can wake */ +#define I2C_CLIENT_SCCB 0x9000 /* Use Omnivision SCCB protocol */ + /* Must match I2C_M_STOP|IGNORE_NAK */ + +/* i2c adapter classes (bitmask) */ +#define I2C_CLASS_HWMON (1<<0) /* lm_sensors, ... */ +#define I2C_CLASS_DDC (1<<3) /* DDC bus on graphics adapters */ +#define I2C_CLASS_SPD (1<<7) /* Memory modules */ +#define I2C_CLASS_DEPRECATED (1<<8) /* Warn users that adapter will stop using classes */ + +/* Internal numbers to terminate lists */ +#define I2C_CLIENT_END 0xfffeU + +/* Construct an I2C_CLIENT_END-terminated array of i2c addresses */ +#define I2C_ADDRS(addr, addrs...) \ + ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END }) + + +/* ----- functions exported by i2c.o */ + +/* administration... + */ +#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE) +extern int i2c_add_adapter(struct i2c_adapter *); +extern void i2c_del_adapter(struct i2c_adapter *); +extern int i2c_add_numbered_adapter(struct i2c_adapter *); + +extern int i2c_register_driver(struct module *, struct i2c_driver *); +extern void i2c_del_driver(struct i2c_driver *); + +/* use a define to avoid include chaining to get THIS_MODULE */ +#define i2c_add_driver(driver) \ + i2c_register_driver(THIS_MODULE, driver) + +extern struct i2c_client *i2c_use_client(struct i2c_client *client); +extern void i2c_release_client(struct i2c_client *client); + +/* call the i2c_client->command() of all attached clients with + * the given arguments */ +extern void i2c_clients_command(struct i2c_adapter *adap, + unsigned int cmd, void *arg); + +extern struct i2c_adapter *i2c_get_adapter(int nr); +extern void i2c_put_adapter(struct i2c_adapter *adap); + + +/* Return the functionality mask */ +static inline u32 i2c_get_functionality(struct i2c_adapter *adap) +{ + return adap->algo->functionality(adap); +} + +/* Return 1 if adapter supports everything we need, 0 if not. */ +static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func) +{ + return (func & i2c_get_functionality(adap)) == func; +} + +/* Return the adapter number for a specific adapter */ +static inline int i2c_adapter_id(struct i2c_adapter *adap) +{ + return adap->nr; +} + +/** + * module_i2c_driver() - Helper macro for registering a I2C driver + * @__i2c_driver: i2c_driver struct + * + * Helper macro for I2C drivers which do not do anything special in module + * init/exit. This eliminates a lot of boilerplate. Each module may only + * use this macro once, and calling it replaces module_init() and module_exit() + */ +#define module_i2c_driver(__i2c_driver) \ + module_driver(__i2c_driver, i2c_add_driver, \ + i2c_del_driver) + +#endif /* I2C */ + +#if IS_ENABLED(CONFIG_OF) +/* must call put_device() when done with returned i2c_client device */ +extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node); + +/* must call put_device() when done with returned i2c_adapter device */ +extern struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node); + +#else + +static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node) +{ + return NULL; +} + +static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node) +{ + return NULL; +} +#endif /* CONFIG_OF */ + +#endif /* _LINUX_I2C_H */ |