linux/drivers/i2c/i2c-core.h
Wolfram Sang df7b4d6f7d i2c: reword explanation about atomic transfers
Atomic transfers are not only about sending messages like the original
wording suggested. Speak of 'accessing' now like in i2c.h.

Reported-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
2020-05-20 15:25:55 +02:00

98 lines
2.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* i2c-core.h - interfaces internal to the I2C framework
*/
#include <linux/rwsem.h>
struct i2c_devinfo {
struct list_head list;
int busnum;
struct i2c_board_info board_info;
};
/* board_lock protects board_list and first_dynamic_bus_num.
* only i2c core components are allowed to use these symbols.
*/
extern struct rw_semaphore __i2c_board_lock;
extern struct list_head __i2c_board_list;
extern int __i2c_first_dynamic_bus_num;
int i2c_check_7bit_addr_validity_strict(unsigned short addr);
int i2c_dev_irq_from_resources(const struct resource *resources,
unsigned int num_resources);
/*
* We only allow atomic transfers for very late communication, e.g. to access a
* PMIC when powering down. Atomic transfers are a corner case and not for
* generic use!
*/
static inline bool i2c_in_atomic_xfer_mode(void)
{
return system_state > SYSTEM_RUNNING && irqs_disabled();
}
static inline int __i2c_lock_bus_helper(struct i2c_adapter *adap)
{
int ret = 0;
if (i2c_in_atomic_xfer_mode()) {
WARN(!adap->algo->master_xfer_atomic && !adap->algo->smbus_xfer_atomic,
"No atomic I2C transfer handler for '%s'\n", dev_name(&adap->dev));
ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT) ? 0 : -EAGAIN;
} else {
i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
}
return ret;
}
static inline int __i2c_check_suspended(struct i2c_adapter *adap)
{
if (test_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags)) {
if (!test_and_set_bit(I2C_ALF_SUSPEND_REPORTED, &adap->locked_flags))
dev_WARN(&adap->dev, "Transfer while suspended\n");
return -ESHUTDOWN;
}
return 0;
}
#ifdef CONFIG_ACPI
const struct acpi_device_id *
i2c_acpi_match_device(const struct acpi_device_id *matches,
struct i2c_client *client);
void i2c_acpi_register_devices(struct i2c_adapter *adap);
int i2c_acpi_get_irq(struct i2c_client *client);
#else /* CONFIG_ACPI */
static inline void i2c_acpi_register_devices(struct i2c_adapter *adap) { }
static inline const struct acpi_device_id *
i2c_acpi_match_device(const struct acpi_device_id *matches,
struct i2c_client *client)
{
return NULL;
}
static inline int i2c_acpi_get_irq(struct i2c_client *client)
{
return 0;
}
#endif /* CONFIG_ACPI */
extern struct notifier_block i2c_acpi_notifier;
#ifdef CONFIG_ACPI_I2C_OPREGION
int i2c_acpi_install_space_handler(struct i2c_adapter *adapter);
void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter);
#else /* CONFIG_ACPI_I2C_OPREGION */
static inline int i2c_acpi_install_space_handler(struct i2c_adapter *adapter) { return 0; }
static inline void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter) { }
#endif /* CONFIG_ACPI_I2C_OPREGION */
#ifdef CONFIG_OF
void of_i2c_register_devices(struct i2c_adapter *adap);
#else
static inline void of_i2c_register_devices(struct i2c_adapter *adap) { }
#endif
extern struct notifier_block i2c_of_notifier;