100 lines
2.3 KiB
C
100 lines
2.3 KiB
C
/*
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* spi_eeprom.c
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* Copyright (C) 2000-2001 Toshiba Corporation
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*
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* 2003-2005 (c) MontaVista Software, Inc. This file is licensed under the
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* terms of the GNU General Public License version 2. This program is
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* licensed "as is" without any warranty of any kind, whether express
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* or implied.
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*
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* Support for TX4938 in 2.6 - Manish Lachwani (mlachwani@mvista.com)
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*/
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#include <linux/init.h>
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#include <linux/device.h>
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#include <linux/spi/spi.h>
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#include <linux/spi/eeprom.h>
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#include <asm/txx9/spi.h>
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#define AT250X0_PAGE_SIZE 8
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/* register board information for at25 driver */
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int __init spi_eeprom_register(int chipid)
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{
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static struct spi_eeprom eeprom = {
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.name = "at250x0",
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.byte_len = 128,
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.page_size = AT250X0_PAGE_SIZE,
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.flags = EE_ADDR1,
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};
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struct spi_board_info info = {
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.modalias = "at25",
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.max_speed_hz = 1500000, /* 1.5Mbps */
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.bus_num = 0,
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.chip_select = chipid,
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.platform_data = &eeprom,
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/* Mode 0: High-Active, Sample-Then-Shift */
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};
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return spi_register_board_info(&info, 1);
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}
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/* simple temporary spi driver to provide early access to seeprom. */
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static struct read_param {
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int chipid;
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int address;
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unsigned char *buf;
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int len;
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} *read_param;
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static int __init early_seeprom_probe(struct spi_device *spi)
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{
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int stat = 0;
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u8 cmd[2];
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int len = read_param->len;
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char *buf = read_param->buf;
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int address = read_param->address;
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dev_info(&spi->dev, "spiclk %u KHz.\n",
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(spi->max_speed_hz + 500) / 1000);
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if (read_param->chipid != spi->chip_select)
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return -ENODEV;
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while (len > 0) {
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/* spi_write_then_read can only work with small chunk */
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int c = len < AT250X0_PAGE_SIZE ? len : AT250X0_PAGE_SIZE;
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cmd[0] = 0x03; /* AT25_READ */
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cmd[1] = address;
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stat = spi_write_then_read(spi, cmd, sizeof(cmd), buf, c);
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buf += c;
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len -= c;
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address += c;
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}
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return stat;
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}
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static struct spi_driver early_seeprom_driver __initdata = {
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.driver = {
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.name = "at25",
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.owner = THIS_MODULE,
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},
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.probe = early_seeprom_probe,
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};
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int __init spi_eeprom_read(int chipid, int address,
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unsigned char *buf, int len)
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{
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int ret;
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struct read_param param = {
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.chipid = chipid,
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.address = address,
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.buf = buf,
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.len = len
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};
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read_param = ¶m;
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ret = spi_register_driver(&early_seeprom_driver);
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if (!ret)
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spi_unregister_driver(&early_seeprom_driver);
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return ret;
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}
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