include/linux/i2c/at24.h

   1 /*
   2  * at24.h - platform_data for the at24 (generic eeprom) driver
   3  * (C) Copyright 2008 by Pengutronix
   4  * (C) Copyright 2012 by Wolfram Sang
   5  * same license as the driver
   6  */
   7
   8 #ifndef _LINUX_AT24_H
   9 #define _LINUX_AT24_H
  10
  11 #include <linux/types.h>
  12 #include <linux/memory.h>
  13
  14 /**
  15  * struct at24_platform_data - data to set up at24 (generic eeprom) driver
  16  * @byte_len: size of eeprom in byte
  17  * @page_size: number of byte which can be written in one go
  18  * @flags: tunable options, check AT24_FLAG_* defines
  19  * @setup: an optional callback invoked after eeprom is probed; enables kernel
  20         code to access eeprom via memory_accessor, see example
  21  * @context: optional parameter passed to setup()
  22  *
  23  * If you set up a custom eeprom type, please double-check the parameters.
  24  * Especially page_size needs extra care, as you risk data loss if your value
  25  * is bigger than what the chip actually supports!
  26  *
  27  * An example in pseudo code for a setup() callback:
  28  *
  29  * void get_mac_addr(struct memory_accessor *mem_acc, void *context)
  30  * {
  31  *      u8 *mac_addr = ethernet_pdata->mac_addr;
  32  *      off_t offset = context;
  33  *
  34  *      // Read MAC addr from EEPROM
  35  *      if (mem_acc->read(mem_acc, mac_addr, offset, ETH_ALEN) == ETH_ALEN)
  36  *              pr_info("Read MAC addr from EEPROM: %pM\n", mac_addr);
  37  * }
  38  *
  39  * This function pointer and context can now be set up in at24_platform_data.
  40  */
  41
  42 struct at24_platform_data {
  43         u32             byte_len;               /* size (sum of all addr) */
  44         u16             page_size;              /* for writes */
  45         u8              flags;
  46 #define AT24_FLAG_ADDR16        0x80    /* address pointer is 16 bit */
  47 #define AT24_FLAG_READONLY      0x40    /* sysfs-entry will be read-only */
  48 #define AT24_FLAG_IRUGO         0x20    /* sysfs-entry will be world-readable */
  49 #define AT24_FLAG_TAKE8ADDR     0x10    /* take always 8 addresses (24c00) */
  50
  51         void            (*setup)(struct memory_accessor *, void *context);
  52         void            *context;
  53 };
  54
  55 #endif /* _LINUX_AT24_H */