arch/mips/txx9/generic/spi_eeprom.c

   1 /*
   2  * spi_eeprom.c
   3  * Copyright (C) 2000-2001 Toshiba Corporation
   4  *
   5  * 2003-2005 (c) MontaVista Software, Inc. This file is licensed under the
   6  * terms of the GNU General Public License version 2. This program is
   7  * licensed "as is" without any warranty of any kind, whether express
   8  * or implied.
   9  *
  10  * Support for TX4938 in 2.6 - Manish Lachwani (mlachwani@mvista.com)
  11  */
  12 #include <linux/init.h>
  13 #include <linux/slab.h>
  14 #include <linux/export.h>
  15 #include <linux/device.h>
  16 #include <linux/spi/spi.h>
  17 #include <linux/spi/eeprom.h>
  18 #include <asm/txx9/spi.h>
  19
  20 #define AT250X0_PAGE_SIZE       8
  21
  22 /* register board information for at25 driver */
  23 int __init spi_eeprom_register(int busid, int chipid, int size)
  24 {
  25         struct spi_board_info info = {
  26                 .modalias = "at25",
  27                 .max_speed_hz = 1500000,        /* 1.5Mbps */
  28                 .bus_num = busid,
  29                 .chip_select = chipid,
  30                 /* Mode 0: High-Active, Sample-Then-Shift */
  31         };
  32         struct spi_eeprom *eeprom;
  33         eeprom = kzalloc(sizeof(*eeprom), GFP_KERNEL);
  34         if (!eeprom)
  35                 return -ENOMEM;
  36         strcpy(eeprom->name, "at250x0");
  37         eeprom->byte_len = size;
  38         eeprom->page_size = AT250X0_PAGE_SIZE;
  39         eeprom->flags = EE_ADDR1;
  40         info.platform_data = eeprom;
  41         return spi_register_board_info(&info, 1);
  42 }
  43
  44 /* simple temporary spi driver to provide early access to seeprom. */
  45
  46 static struct read_param {
  47         int busid;
  48         int chipid;
  49         int address;
  50         unsigned char *buf;
  51         int len;
  52 } *read_param;
  53
  54 static int __init early_seeprom_probe(struct spi_device *spi)
  55 {
  56         int stat = 0;
  57         u8 cmd[2];
  58         int len = read_param->len;
  59         char *buf = read_param->buf;
  60         int address = read_param->address;
  61
  62         dev_info(&spi->dev, "spiclk %u KHz.\n",
  63                  (spi->max_speed_hz + 500) / 1000);
  64         if (read_param->busid != spi->master->bus_num ||
  65             read_param->chipid != spi->chip_select)
  66                 return -ENODEV;
  67         while (len > 0) {
  68                 /* spi_write_then_read can only work with small chunk */
  69                 int c = len < AT250X0_PAGE_SIZE ? len : AT250X0_PAGE_SIZE;
  70                 cmd[0] = 0x03;  /* AT25_READ */
  71                 cmd[1] = address;
  72                 stat = spi_write_then_read(spi, cmd, sizeof(cmd), buf, c);
  73                 buf += c;
  74                 len -= c;
  75                 address += c;
  76         }
  77         return stat;
  78 }
  79
  80 static struct spi_driver early_seeprom_driver __initdata = {
  81         .driver = {
  82                 .name   = "at25",
  83                 .owner  = THIS_MODULE,
  84         },
  85         .probe  = early_seeprom_probe,
  86 };
  87
  88 int __init spi_eeprom_read(int busid, int chipid, int address,
  89                            unsigned char *buf, int len)
  90 {
  91         int ret;
  92         struct read_param param = {
  93                 .busid = busid,
  94                 .chipid = chipid,
  95                 .address = address,
  96                 .buf = buf,
  97                 .len = len
  98         };
  99
 100         read_param = &param;
 101         ret = spi_register_driver(&early_seeprom_driver);
 102         if (!ret)
 103                 spi_unregister_driver(&early_seeprom_driver);
 104         return ret;
 105 }