drivers/i2c/i2c-core.h

   1 /*
   2  * i2c-core.h - interfaces internal to the I2C framework
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #include <linux/rwsem.h>
  16
  17 struct i2c_devinfo {
  18         struct list_head        list;
  19         int                     busnum;
  20         struct i2c_board_info   board_info;
  21 };
  22
  23 /* board_lock protects board_list and first_dynamic_bus_num.
  24  * only i2c core components are allowed to use these symbols.
  25  */
  26 extern struct rw_semaphore      __i2c_board_lock;
  27 extern struct list_head __i2c_board_list;
  28 extern int              __i2c_first_dynamic_bus_num;
  29
  30 int i2c_check_7bit_addr_validity_strict(unsigned short addr);
  31
  32 /*
  33  * We only allow atomic transfers for very late communication, e.g. to send
  34  * the powerdown command to a PMIC. Atomic transfers are a corner case and not
  35  * for generic use!
  36  */
  37 static inline bool i2c_in_atomic_xfer_mode(void)
  38 {
  39         return system_state > SYSTEM_RUNNING && irqs_disabled();
  40 }
  41
  42 static inline int __i2c_lock_bus_helper(struct i2c_adapter *adap)
  43 {
  44         int ret = 0;
  45
  46         if (i2c_in_atomic_xfer_mode()) {
  47                 WARN(!adap->algo->master_xfer_atomic && !adap->algo->smbus_xfer_atomic,
  48                      "No atomic I2C transfer handler for '%s'\n", dev_name(&adap->dev));
  49                 ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT) ? 0 : -EAGAIN;
  50         } else {
  51                 i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
  52         }
  53
  54         return ret;
  55 }
  56
  57 static inline int __i2c_check_suspended(struct i2c_adapter *adap)
  58 {
  59         if (test_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags)) {
  60                 if (!test_and_set_bit(I2C_ALF_SUSPEND_REPORTED, &adap->locked_flags))
  61                         dev_WARN(&adap->dev, "Transfer while suspended\n");
  62                 return -ESHUTDOWN;
  63         }
  64
  65         return 0;
  66 }
  67
  68 #ifdef CONFIG_ACPI
  69 const struct acpi_device_id *
  70 i2c_acpi_match_device(const struct acpi_device_id *matches,
  71                       struct i2c_client *client);
  72 void i2c_acpi_register_devices(struct i2c_adapter *adap);
  73 #else /* CONFIG_ACPI */
  74 static inline void i2c_acpi_register_devices(struct i2c_adapter *adap) { }
  75 static inline const struct acpi_device_id *
  76 i2c_acpi_match_device(const struct acpi_device_id *matches,
  77                       struct i2c_client *client)
  78 {
  79         return NULL;
  80 }
  81 #endif /* CONFIG_ACPI */
  82 extern struct notifier_block i2c_acpi_notifier;
  83
  84 #ifdef CONFIG_ACPI_I2C_OPREGION
  85 int i2c_acpi_install_space_handler(struct i2c_adapter *adapter);
  86 void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter);
  87 #else /* CONFIG_ACPI_I2C_OPREGION */
  88 static inline int i2c_acpi_install_space_handler(struct i2c_adapter *adapter) { return 0; }
  89 static inline void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter) { }
  90 #endif /* CONFIG_ACPI_I2C_OPREGION */
  91
  92 #ifdef CONFIG_OF
  93 void of_i2c_register_devices(struct i2c_adapter *adap);
  94 #else
  95 static inline void of_i2c_register_devices(struct i2c_adapter *adap) { }
  96 #endif
  97 extern struct notifier_block i2c_of_notifier;