i2c-core.h

  1/* SPDX-License-Identifier: GPL-2.0-or-later */
  2/*
  3 * i2c-core.h - interfaces internal to the I2C framework
  4 */
  5
  6#include <linux/kconfig.h>
  7#include <linux/rwsem.h>
  8
  9struct i2c_devinfo {
 10	struct list_head	list;
 11	int			busnum;
 12	struct i2c_board_info	board_info;
 13};
 14
 15/* board_lock protects board_list and first_dynamic_bus_num.
 16 * only i2c core components are allowed to use these symbols.
 17 */
 18extern struct rw_semaphore	__i2c_board_lock;
 19extern struct list_head	__i2c_board_list;
 20extern int		__i2c_first_dynamic_bus_num;
 21
 22int i2c_check_7bit_addr_validity_strict(unsigned short addr);
 23int i2c_dev_irq_from_resources(const struct resource *resources,
 24			       unsigned int num_resources);
 25
 26/*
 27 * We only allow atomic transfers for very late communication, e.g. to access a
 28 * PMIC when powering down. Atomic transfers are a corner case and not for
 29 * generic use!
 30 */
 31static inline bool i2c_in_atomic_xfer_mode(void)
 32{
 33	return system_state > SYSTEM_RUNNING &&
 34	       (IS_ENABLED(CONFIG_PREEMPT_COUNT) ? !preemptible() : irqs_disabled());
 35}
 36
 37static inline int __i2c_lock_bus_helper(struct i2c_adapter *adap)
 38{
 39	int ret = 0;
 40
 41	if (i2c_in_atomic_xfer_mode()) {
 42		WARN(!adap->algo->master_xfer_atomic && !adap->algo->smbus_xfer_atomic,
 43		     "No atomic I2C transfer handler for '%s'\n", dev_name(&adap->dev));
 44		ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT) ? 0 : -EAGAIN;
 45	} else {
 46		i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
 47	}
 48
 49	return ret;
 50}
 51
 52static inline int __i2c_check_suspended(struct i2c_adapter *adap)
 53{
 54	if (test_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags)) {
 55		if (!test_and_set_bit(I2C_ALF_SUSPEND_REPORTED, &adap->locked_flags))
 56			dev_WARN(&adap->dev, "Transfer while suspended\n");
 57		return -ESHUTDOWN;
 58	}
 59
 60	return 0;
 61}
 62
 63#ifdef CONFIG_ACPI
 64void i2c_acpi_register_devices(struct i2c_adapter *adap);
 65
 66int i2c_acpi_get_irq(struct i2c_client *client, bool *wake_capable);
 67#else /* CONFIG_ACPI */
 68static inline void i2c_acpi_register_devices(struct i2c_adapter *adap) { }
 69
 70static inline int i2c_acpi_get_irq(struct i2c_client *client, bool *wake_capable)
 71{
 72	return 0;
 73}
 74#endif /* CONFIG_ACPI */
 75extern struct notifier_block i2c_acpi_notifier;
 76
 77#ifdef CONFIG_ACPI_I2C_OPREGION
 78int i2c_acpi_install_space_handler(struct i2c_adapter *adapter);
 79void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter);
 80#else /* CONFIG_ACPI_I2C_OPREGION */
 81static inline int i2c_acpi_install_space_handler(struct i2c_adapter *adapter) { return 0; }
 82static inline void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter) { }
 83#endif /* CONFIG_ACPI_I2C_OPREGION */
 84
 85#ifdef CONFIG_OF
 86void of_i2c_register_devices(struct i2c_adapter *adap);
 87const struct of_device_id *i2c_of_match_device(const struct of_device_id *matches,
 88					       struct i2c_client *client);
 89
 90#else
 91static inline void of_i2c_register_devices(struct i2c_adapter *adap) { }
 92static inline
 93const struct of_device_id *i2c_of_match_device(const struct of_device_id *matches,
 94					       struct i2c_client *client)
 95{
 96	return NULL;
 97}
 98#endif
 99extern struct notifier_block i2c_of_notifier;
100
101#if IS_ENABLED(CONFIG_I2C_SMBUS)
102int i2c_setup_smbus_alert(struct i2c_adapter *adap);
103#else
104static inline int i2c_setup_smbus_alert(struct i2c_adapter *adap)
105{
106	return 0;
107}
108#endif