/* ------------------------------------------------------------------------- */ /* */ /* 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 and Frodo Looijaard */ #ifndef _LINUX_I2C_H #define _LINUX_I2C_H #include #include /* for struct device */ #include /* for completion */ #include #include /* for struct device_node */ #include /* for swab16 */ #include 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_REQ_READ_START, I2C_SLAVE_REQ_READ_END, I2C_SLAVE_REQ_WRITE_START, I2C_SLAVE_REQ_WRITE_END, 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 * @acpi_node: ACPI device node * @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 acpi_dev_node acpi_node; 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_bus_recovery_info *bri); void (*unprepare_recovery)(struct i2c_bus_recovery_info *bri); /* 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 */