include/linux/platform_data/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/nvmem-consumer.h>
  13 #include <linux/bitops.h>
  14
  15 /**
  16  * struct at24_platform_data - data to set up at24 (generic eeprom) driver
  17  * @byte_len: size of eeprom in byte
  18  * @page_size: number of byte which can be written in one go
  19  * @flags: tunable options, check AT24_FLAG_* defines
  20  * @setup: an optional callback invoked after eeprom is probed; enables kernel
  21         code to access eeprom via nvmem, see example
  22  * @context: optional parameter passed to setup()
  23  *
  24  * If you set up a custom eeprom type, please double-check the parameters.
  25  * Especially page_size needs extra care, as you risk data loss if your value
  26  * is bigger than what the chip actually supports!
  27  *
  28  * An example in pseudo code for a setup() callback:
  29  *
  30  * void get_mac_addr(struct nvmem_device *nvmem, void *context)
  31  * {
  32  *      u8 *mac_addr = ethernet_pdata->mac_addr;
  33  *      off_t offset = context;
  34  *
  35  *      // Read MAC addr from EEPROM
  36  *      if (nvmem_device_read(nvmem, offset, ETH_ALEN, mac_addr) == ETH_ALEN)
  37  *              pr_info("Read MAC addr from EEPROM: %pM\n", mac_addr);
  38  * }
  39  *
  40  * This function pointer and context can now be set up in at24_platform_data.
  41  */
  42
  43 struct at24_platform_data {
  44         u32             byte_len;               /* size (sum of all addr) */
  45         u16             page_size;              /* for writes */
  46         u8              flags;
  47 #define AT24_FLAG_ADDR16        BIT(7)  /* address pointer is 16 bit */
  48 #define AT24_FLAG_READONLY      BIT(6)  /* sysfs-entry will be read-only */
  49 #define AT24_FLAG_IRUGO         BIT(5)  /* sysfs-entry will be world-readable */
  50 #define AT24_FLAG_TAKE8ADDR     BIT(4)  /* take always 8 addresses (24c00) */
  51 #define AT24_FLAG_SERIAL        BIT(3)  /* factory-programmed serial number */
  52 #define AT24_FLAG_MAC           BIT(2)  /* factory-programmed mac address */
  53 #define AT24_FLAG_NO_RDROL      BIT(1)  /* does not auto-rollover reads to */
  54                                         /* the next slave address */
  55
  56         void            (*setup)(struct nvmem_device *nvmem, void *context);
  57         void            *context;
  58 };
  59
  60 #endif /* _LINUX_AT24_H */