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/device.h>
  15 #include <linux/spi/spi.h>
  16 #include <linux/spi/eeprom.h>
  17 #include <asm/txx9/spi.h>
  18
  19 #define AT250X0_PAGE_SIZE       8
  20
  21 /* register board information for at25 driver */
  22 int __init spi_eeprom_register(int busid, int chipid, int size)
  23 {
  24         struct spi_board_info info = {
  25                 .modalias = "at25",
  26                 .max_speed_hz = 1500000,        /* 1.5Mbps */
  27                 .bus_num = busid,
  28                 .chip_select = chipid,
  29                 /* Mode 0: High-Active, Sample-Then-Shift */
  30         };
  31         struct spi_eeprom *eeprom;
  32         eeprom = kzalloc(sizeof(*eeprom), GFP_KERNEL);
  33         if (!eeprom)
  34                 return -ENOMEM;
  35         strcpy(eeprom->name, "at250x0");
  36         eeprom->byte_len = size;
  37         eeprom->page_size = AT250X0_PAGE_SIZE;
  38         eeprom->flags = EE_ADDR1;
  39         info.platform_data = eeprom;
  40         return spi_register_board_info(&info, 1);
  41 }
  42
  43 /* simple temporary spi driver to provide early access to seeprom. */
  44
  45 static struct read_param {
  46         int busid;
  47         int chipid;
  48         int address;
  49         unsigned char *buf;
  50         int len;
  51 } *read_param;
  52
  53 static int __init early_seeprom_probe(struct spi_device *spi)
  54 {
  55         int stat = 0;
  56         u8 cmd[2];
  57         int len = read_param->len;
  58         char *buf = read_param->buf;
  59         int address = read_param->address;
  60
  61         dev_info(&spi->dev, "spiclk %u KHz.\n",
  62                  (spi->max_speed_hz + 500) / 1000);
  63         if (read_param->busid != spi->master->bus_num ||
  64             read_param->chipid != spi->chip_select)
  65                 return -ENODEV;
  66         while (len > 0) {
  67                 /* spi_write_then_read can only work with small chunk */
  68                 int c = len < AT250X0_PAGE_SIZE ? len : AT250X0_PAGE_SIZE;
  69                 cmd[0] = 0x03;  /* AT25_READ */
  70                 cmd[1] = address;
  71                 stat = spi_write_then_read(spi, cmd, sizeof(cmd), buf, c);
  72                 buf += c;
  73                 len -= c;
  74                 address += c;
  75         }
  76         return stat;
  77 }
  78
  79 static struct spi_driver early_seeprom_driver __initdata = {
  80         .driver = {
  81                 .name   = "at25",
  82                 .owner  = THIS_MODULE,
  83         },
  84         .probe  = early_seeprom_probe,
  85 };
  86
  87 int __init spi_eeprom_read(int busid, int chipid, int address,
  88                            unsigned char *buf, int len)
  89 {
  90         int ret;
  91         struct read_param param = {
  92                 .busid = busid,
  93                 .chipid = chipid,
  94                 .address = address,
  95                 .buf = buf,
  96                 .len = len
  97         };
  98
  99         read_param = &param;
 100         ret = spi_register_driver(&early_seeprom_driver);
 101         if (!ret)
 102                 spi_unregister_driver(&early_seeprom_driver);
 103         return ret;
 104 }