LXR linux/arch/mips/txx9/generic/spi

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