v4.19.13 snapshot.
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
new file mode 100644
index 0000000..65b4eae
--- /dev/null
+++ b/include/linux/i2c.h
@@ -0,0 +1,952 @@
+/* ------------------------------------------------------------------------- */
+/* */
+/* 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/rtmutex.h>
+#include <linux/irqdomain.h> /* for Host Notify IRQ */
+#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;
+extern struct device_type i2c_client_type;
+
+/* --- General options ------------------------------------------------ */
+
+struct i2c_msg;
+struct i2c_algorithm;
+struct i2c_adapter;
+struct i2c_client;
+struct i2c_driver;
+struct i2c_device_identity;
+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;
+struct property_entry;
+
+#if IS_ENABLED(CONFIG_I2C)
+/*
+ * 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_transfer_buffer_flags(const struct i2c_client *client,
+ char *buf, int count, u16 flags);
+
+/**
+ * i2c_master_recv - issue a single I2C message in master receive mode
+ * @client: Handle to slave device
+ * @buf: Where to store data read from slave
+ * @count: How many bytes to read, must be less than 64k since msg.len is u16
+ *
+ * Returns negative errno, or else the number of bytes read.
+ */
+static inline int i2c_master_recv(const struct i2c_client *client,
+ char *buf, int count)
+{
+ return i2c_transfer_buffer_flags(client, buf, count, I2C_M_RD);
+};
+
+/**
+ * i2c_master_recv_dmasafe - issue a single I2C message in master receive mode
+ * using a DMA safe buffer
+ * @client: Handle to slave device
+ * @buf: Where to store data read from slave, must be safe to use with DMA
+ * @count: How many bytes to read, must be less than 64k since msg.len is u16
+ *
+ * Returns negative errno, or else the number of bytes read.
+ */
+static inline int i2c_master_recv_dmasafe(const struct i2c_client *client,
+ char *buf, int count)
+{
+ return i2c_transfer_buffer_flags(client, buf, count,
+ I2C_M_RD | I2C_M_DMA_SAFE);
+};
+
+/**
+ * i2c_master_send - issue a single I2C message in master transmit mode
+ * @client: Handle to slave device
+ * @buf: Data that will be written to the slave
+ * @count: How many bytes to write, must be less than 64k since msg.len is u16
+ *
+ * Returns negative errno, or else the number of bytes written.
+ */
+static inline int i2c_master_send(const struct i2c_client *client,
+ const char *buf, int count)
+{
+ return i2c_transfer_buffer_flags(client, (char *)buf, count, 0);
+};
+
+/**
+ * i2c_master_send_dmasafe - issue a single I2C message in master transmit mode
+ * using a DMA safe buffer
+ * @client: Handle to slave device
+ * @buf: Data that will be written to the slave, must be safe to use with DMA
+ * @count: How many bytes to write, must be less than 64k since msg.len is u16
+ *
+ * Returns negative errno, or else the number of bytes written.
+ */
+static inline int i2c_master_send_dmasafe(const struct i2c_client *client,
+ const char *buf, int count)
+{
+ return i2c_transfer_buffer_flags(client, (char *)buf, count,
+ I2C_M_DMA_SAFE);
+};
+
+/* 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. */
+s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
+ unsigned short flags, char read_write, u8 command,
+ int protocol, union i2c_smbus_data *data);
+
+/* Unlocked flavor */
+s32 __i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
+ unsigned short flags, char read_write, u8 command,
+ int protocol, 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);
+extern s32
+i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
+ u8 command, u8 length, u8 *values);
+int i2c_get_device_id(const struct i2c_client *client,
+ struct i2c_device_identity *id);
+#endif /* I2C */
+
+/**
+ * struct i2c_device_identity - i2c client device identification
+ * @manufacturer_id: 0 - 4095, database maintained by NXP
+ * @part_id: 0 - 511, according to manufacturer
+ * @die_revision: 0 - 7, according to manufacturer
+ */
+struct i2c_device_identity {
+ u16 manufacturer_id;
+#define I2C_DEVICE_ID_NXP_SEMICONDUCTORS 0
+#define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_1 1
+#define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_2 2
+#define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_3 3
+#define I2C_DEVICE_ID_RAMTRON_INTERNATIONAL 4
+#define I2C_DEVICE_ID_ANALOG_DEVICES 5
+#define I2C_DEVICE_ID_STMICROELECTRONICS 6
+#define I2C_DEVICE_ID_ON_SEMICONDUCTOR 7
+#define I2C_DEVICE_ID_SPRINTEK_CORPORATION 8
+#define I2C_DEVICE_ID_ESPROS_PHOTONICS_AG 9
+#define I2C_DEVICE_ID_FUJITSU_SEMICONDUCTOR 10
+#define I2C_DEVICE_ID_FLIR 11
+#define I2C_DEVICE_ID_O2MICRO 12
+#define I2C_DEVICE_ID_ATMEL 13
+#define I2C_DEVICE_ID_NONE 0xffff
+ u16 part_id;
+ u8 die_revision;
+};
+
+enum i2c_alert_protocol {
+ I2C_PROTOCOL_SMBUS_ALERT,
+ I2C_PROTOCOL_SMBUS_HOST_NOTIFY,
+};
+
+/**
+ * struct i2c_driver - represent an I2C device driver
+ * @class: What kind of i2c device we instantiate (for detect)
+ * @probe: Callback for device binding - soon to be deprecated
+ * @probe_new: New 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)
+ * @disable_i2c_core_irq_mapping: Tell the i2c-core to not do irq-mapping
+ *
+ * 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;
+
+ /* Standard driver model interfaces */
+ int (*probe)(struct i2c_client *, const struct i2c_device_id *);
+ int (*remove)(struct i2c_client *);
+
+ /* New driver model interface to aid the seamless removal of the
+ * current probe()'s, more commonly unused than used second parameter.
+ */
+ int (*probe_new)(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").
+ * For the SMBus Host Notify protocol, the data corresponds to the
+ * 16-bit payload data reported by the slave device acting as master.
+ */
+ void (*alert)(struct i2c_client *, enum i2c_alert_protocol protocol,
+ 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;
+
+ bool disable_i2c_core_irq_mapping;
+};
+#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);
+extern const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
+ const struct i2c_client *client);
+
+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);
+extern bool i2c_detect_slave_mode(struct device *dev);
+
+static inline int i2c_slave_event(struct i2c_client *client,
+ enum i2c_slave_event event, u8 *val)
+{
+ return client->slave_cb(client, event, val);
+}
+#else
+static inline bool i2c_detect_slave_mode(struct device *dev) { return false; }
+#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
+ * @dev_name: Overrides the default <busnr>-<addr> dev_name if set
+ * @platform_data: stored in i2c_client.dev.platform_data
+ * @of_node: pointer to OpenFirmware device node
+ * @fwnode: device node supplied by the platform firmware
+ * @properties: additional device properties for the device
+ * @resources: resources associated with the device
+ * @num_resources: number of resources in the @resources array
+ * @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;
+ const char *dev_name;
+ void *platform_data;
+ struct device_node *of_node;
+ struct fwnode_handle *fwnode;
+ const struct property_entry *properties;
+ const struct resource *resources;
+ unsigned int num_resources;
+ 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 IS_ENABLED(CONFIG_I2C)
+/* 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 struct i2c_client *
+i2c_new_secondary_device(struct i2c_client *client,
+ const char *name,
+ u16 default_addr);
+
+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_lock_operations - represent I2C locking operations
+ * @lock_bus: Get exclusive access to an I2C bus segment
+ * @trylock_bus: Try to get exclusive access to an I2C bus segment
+ * @unlock_bus: Release exclusive access to an I2C bus segment
+ *
+ * The main operations are wrapped by i2c_lock_bus and i2c_unlock_bus.
+ */
+struct i2c_lock_operations {
+ void (*lock_bus)(struct i2c_adapter *, unsigned int flags);
+ int (*trylock_bus)(struct i2c_adapter *, unsigned int flags);
+ void (*unlock_bus)(struct i2c_adapter *, unsigned int flags);
+};
+
+/**
+ * struct i2c_timings - I2C timing information
+ * @bus_freq_hz: the bus frequency in Hz
+ * @scl_rise_ns: time SCL signal takes to rise in ns; t(r) in the I2C specification
+ * @scl_fall_ns: time SCL signal takes to fall in ns; t(f) in the I2C specification
+ * @scl_int_delay_ns: time IP core additionally needs to setup SCL in ns
+ * @sda_fall_ns: time SDA signal takes to fall in ns; t(f) in the I2C specification
+ * @sda_hold_ns: time IP core additionally needs to hold SDA in ns
+ */
+struct i2c_timings {
+ u32 bus_freq_hz;
+ u32 scl_rise_ns;
+ u32 scl_fall_ns;
+ u32 scl_int_delay_ns;
+ u32 sda_fall_ns;
+ u32 sda_hold_ns;
+};
+
+/**
+ * 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().
+ * @get_scl: This gets current value of SCL line. Mandatory for generic SCL
+ * recovery. Populated internally for generic GPIO recovery.
+ * @set_scl: This sets/clears the SCL line. Mandatory for generic SCL recovery.
+ * Populated internally for generic GPIO recovery.
+ * @get_sda: This gets current value of SDA line. This or set_sda() is mandatory
+ * for generic SCL recovery. Populated internally, if sda_gpio is a valid
+ * GPIO, for generic GPIO recovery.
+ * @set_sda: This sets/clears the SDA line. This or get_sda() is mandatory for
+ * generic SCL recovery. Populated internally, if sda_gpio is a valid GPIO,
+ * for generic GPIO recovery.
+ * @get_bus_free: Returns the bus free state as seen from the IP core in case it
+ * has a more complex internal logic than just reading SDA. Optional.
+ * @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_gpiod: gpiod of the SCL line. Only required for GPIO recovery.
+ * @sda_gpiod: gpiod of the SDA line. Only required for GPIO recovery.
+ */
+struct i2c_bus_recovery_info {
+ int (*recover_bus)(struct i2c_adapter *adap);
+
+ int (*get_scl)(struct i2c_adapter *adap);
+ void (*set_scl)(struct i2c_adapter *adap, int val);
+ int (*get_sda)(struct i2c_adapter *adap);
+ void (*set_sda)(struct i2c_adapter *adap, int val);
+ int (*get_bus_free)(struct i2c_adapter *adap);
+
+ void (*prepare_recovery)(struct i2c_adapter *adap);
+ void (*unprepare_recovery)(struct i2c_adapter *adap);
+
+ /* gpio recovery */
+ struct gpio_desc *scl_gpiod;
+ struct gpio_desc *sda_gpiod;
+};
+
+int i2c_recover_bus(struct i2c_adapter *adap);
+
+/* Generic recovery routines */
+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)
+/* clock stretching is not supported */
+#define I2C_AQ_NO_CLK_STRETCH BIT(4)
+/* message cannot have length of 0 */
+#define I2C_AQ_NO_ZERO_LEN_READ BIT(5)
+#define I2C_AQ_NO_ZERO_LEN_WRITE BIT(6)
+#define I2C_AQ_NO_ZERO_LEN (I2C_AQ_NO_ZERO_LEN_READ | I2C_AQ_NO_ZERO_LEN_WRITE)
+
+/*
+ * 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 */
+ const struct i2c_lock_operations *lock_ops;
+ struct rt_mutex bus_lock;
+ struct rt_mutex mux_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;
+
+ struct irq_domain *host_notify_domain;
+};
+#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 */
+#define I2C_LOCK_ROOT_ADAPTER BIT(0)
+#define I2C_LOCK_SEGMENT BIT(1)
+
+/**
+ * i2c_lock_bus - Get exclusive access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
+ * locks only this branch in the adapter tree
+ */
+static inline void
+i2c_lock_bus(struct i2c_adapter *adapter, unsigned int flags)
+{
+ adapter->lock_ops->lock_bus(adapter, flags);
+}
+
+/**
+ * i2c_trylock_bus - Try to get exclusive access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ * @flags: I2C_LOCK_ROOT_ADAPTER tries to locks the root i2c adapter,
+ * I2C_LOCK_SEGMENT tries to lock only this branch in the adapter tree
+ *
+ * Return: true if the I2C bus segment is locked, false otherwise
+ */
+static inline int
+i2c_trylock_bus(struct i2c_adapter *adapter, unsigned int flags)
+{
+ return adapter->lock_ops->trylock_bus(adapter, flags);
+}
+
+/**
+ * i2c_unlock_bus - Release exclusive access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
+ * unlocks only this branch in the adapter tree
+ */
+static inline void
+i2c_unlock_bus(struct i2c_adapter *adapter, unsigned int flags)
+{
+ adapter->lock_ops->unlock_bus(adapter, flags);
+}
+
+/*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_SLAVE 0x20 /* we are the slave */
+#define I2C_CLIENT_HOST_NOTIFY 0x40 /* We want to use I2C host notify */
+#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 */
+/* Warn users that the adapter doesn't support classes anymore */
+#define I2C_CLASS_DEPRECATED (1<<8)
+
+/* 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 IS_ENABLED(CONFIG_I2C)
+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);
+extern unsigned int i2c_adapter_depth(struct i2c_adapter *adapter);
+
+void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults);
+
+/* 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;
+}
+
+/**
+ * i2c_check_quirks() - Function for checking the quirk flags in an i2c adapter
+ * @adap: i2c adapter
+ * @quirks: quirk flags
+ *
+ * Return: true if the adapter has all the specified quirk flags, false if not
+ */
+static inline bool i2c_check_quirks(struct i2c_adapter *adap, u64 quirks)
+{
+ if (!adap->quirks)
+ return false;
+ return (adap->quirks->flags & quirks) == quirks;
+}
+
+/* Return the adapter number for a specific adapter */
+static inline int i2c_adapter_id(struct i2c_adapter *adap)
+{
+ return adap->nr;
+}
+
+static inline u8 i2c_8bit_addr_from_msg(const struct i2c_msg *msg)
+{
+ return (msg->addr << 1) | (msg->flags & I2C_M_RD ? 1 : 0);
+}
+
+u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold);
+void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred);
+
+int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr);
+/**
+ * module_i2c_driver() - Helper macro for registering a modular 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)
+
+/**
+ * builtin_i2c_driver() - Helper macro for registering a builtin I2C driver
+ * @__i2c_driver: i2c_driver struct
+ *
+ * Helper macro for I2C drivers which do not do anything special in their
+ * init. This eliminates a lot of boilerplate. Each driver may only
+ * use this macro once, and calling it replaces device_initcall().
+ */
+#define builtin_i2c_driver(__i2c_driver) \
+ builtin_driver(__i2c_driver, i2c_add_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);
+
+/* must call i2c_put_adapter() when done with returned i2c_adapter device */
+struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node);
+
+extern const struct of_device_id
+*i2c_of_match_device(const struct of_device_id *matches,
+ struct i2c_client *client);
+
+int of_i2c_get_board_info(struct device *dev, struct device_node *node,
+ struct i2c_board_info *info);
+
+#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;
+}
+
+static inline struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
+{
+ return NULL;
+}
+
+static inline const struct of_device_id
+*i2c_of_match_device(const struct of_device_id *matches,
+ struct i2c_client *client)
+{
+ return NULL;
+}
+
+static inline int of_i2c_get_board_info(struct device *dev,
+ struct device_node *node,
+ struct i2c_board_info *info)
+{
+ return -ENOTSUPP;
+}
+
+#endif /* CONFIG_OF */
+
+#if IS_ENABLED(CONFIG_ACPI)
+u32 i2c_acpi_find_bus_speed(struct device *dev);
+struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
+ struct i2c_board_info *info);
+#else
+static inline u32 i2c_acpi_find_bus_speed(struct device *dev)
+{
+ return 0;
+}
+static inline struct i2c_client *i2c_acpi_new_device(struct device *dev,
+ int index, struct i2c_board_info *info)
+{
+ return NULL;
+}
+#endif /* CONFIG_ACPI */
+
+#endif /* _LINUX_I2C_H */