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83c42212d2
If I2C transfers are executed in atomic contexts, trylock is used instead of lock. This behaviour was missing for SMBUS, although a lot of transfers are of SMBUS type, either emulated or direct. So, factor out the locking routine into a helper and use it for I2C and SMBUS. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
84 lines
2.6 KiB
C
84 lines
2.6 KiB
C
/*
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* i2c-core.h - interfaces internal to the I2C framework
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/rwsem.h>
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struct i2c_devinfo {
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struct list_head list;
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int busnum;
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struct i2c_board_info board_info;
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};
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/* board_lock protects board_list and first_dynamic_bus_num.
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* only i2c core components are allowed to use these symbols.
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*/
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extern struct rw_semaphore __i2c_board_lock;
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extern struct list_head __i2c_board_list;
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extern int __i2c_first_dynamic_bus_num;
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int i2c_check_7bit_addr_validity_strict(unsigned short addr);
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/*
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* We only allow atomic transfers for very late communication, e.g. to send
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* the powerdown command to a PMIC. Atomic transfers are a corner case and not
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* for generic use!
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*/
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static inline bool i2c_in_atomic_xfer_mode(void)
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{
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return system_state > SYSTEM_RUNNING && irqs_disabled();
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}
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static inline int __i2c_lock_bus_helper(struct i2c_adapter *adap)
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{
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int ret = 0;
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if (i2c_in_atomic_xfer_mode())
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ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT) ? 0 : -EAGAIN;
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else
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i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
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return ret;
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}
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#ifdef CONFIG_ACPI
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const struct acpi_device_id *
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i2c_acpi_match_device(const struct acpi_device_id *matches,
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struct i2c_client *client);
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void i2c_acpi_register_devices(struct i2c_adapter *adap);
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#else /* CONFIG_ACPI */
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static inline void i2c_acpi_register_devices(struct i2c_adapter *adap) { }
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static inline const struct acpi_device_id *
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i2c_acpi_match_device(const struct acpi_device_id *matches,
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struct i2c_client *client)
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{
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return NULL;
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}
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#endif /* CONFIG_ACPI */
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extern struct notifier_block i2c_acpi_notifier;
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#ifdef CONFIG_ACPI_I2C_OPREGION
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int i2c_acpi_install_space_handler(struct i2c_adapter *adapter);
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void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter);
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#else /* CONFIG_ACPI_I2C_OPREGION */
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static inline int i2c_acpi_install_space_handler(struct i2c_adapter *adapter) { return 0; }
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static inline void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter) { }
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#endif /* CONFIG_ACPI_I2C_OPREGION */
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#ifdef CONFIG_OF
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void of_i2c_register_devices(struct i2c_adapter *adap);
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#else
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static inline void of_i2c_register_devices(struct i2c_adapter *adap) { }
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#endif
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extern struct notifier_block i2c_of_notifier;
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