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kernel/linux-rt-4.4.41/include/linux/platform_data/at24.h 1.81 KB
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  /*
   * at24.h - platform_data for the at24 (generic eeprom) driver
   * (C) Copyright 2008 by Pengutronix
   * (C) Copyright 2012 by Wolfram Sang
   * same license as the driver
   */
  
  #ifndef _LINUX_AT24_H
  #define _LINUX_AT24_H
  
  #include <linux/types.h>
  #include <linux/memory.h>
  
  /**
   * struct at24_platform_data - data to set up at24 (generic eeprom) driver
   * @byte_len: size of eeprom in byte
   * @page_size: number of byte which can be written in one go
   * @flags: tunable options, check AT24_FLAG_* defines
   * @setup: an optional callback invoked after eeprom is probed; enables kernel
  	code to access eeprom via memory_accessor, see example
   * @context: optional parameter passed to setup()
   *
   * If you set up a custom eeprom type, please double-check the parameters.
   * Especially page_size needs extra care, as you risk data loss if your value
   * is bigger than what the chip actually supports!
   *
   * An example in pseudo code for a setup() callback:
   *
   * void get_mac_addr(struct memory_accessor *mem_acc, void *context)
   * {
   *	u8 *mac_addr = ethernet_pdata->mac_addr;
   *	off_t offset = context;
   *
   *	// Read MAC addr from EEPROM
   *	if (mem_acc->read(mem_acc, mac_addr, offset, ETH_ALEN) == ETH_ALEN)
   *		pr_info("Read MAC addr from EEPROM: %pM
  ", mac_addr);
   * }
   *
   * This function pointer and context can now be set up in at24_platform_data.
   */
  
  struct at24_platform_data {
  	u32		byte_len;		/* size (sum of all addr) */
  	u16		page_size;		/* for writes */
  	u8		flags;
  #define AT24_FLAG_ADDR16	0x80	/* address pointer is 16 bit */
  #define AT24_FLAG_READONLY	0x40	/* sysfs-entry will be read-only */
  #define AT24_FLAG_IRUGO		0x20	/* sysfs-entry will be world-readable */
  #define AT24_FLAG_TAKE8ADDR	0x10	/* take always 8 addresses (24c00) */
  
  	void		(*setup)(struct memory_accessor *, void *context);
  	void		*context;
  };
  
  #endif /* _LINUX_AT24_H */