1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun * spi_eeprom.c
3*4882a593Smuzhiyun * Copyright (C) 2000-2001 Toshiba Corporation
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * 2003-2005 (c) MontaVista Software, Inc. This file is licensed under the
6*4882a593Smuzhiyun * terms of the GNU General Public License version 2. This program is
7*4882a593Smuzhiyun * licensed "as is" without any warranty of any kind, whether express
8*4882a593Smuzhiyun * or implied.
9*4882a593Smuzhiyun *
10*4882a593Smuzhiyun * Support for TX4938 in 2.6 - Manish Lachwani (mlachwani@mvista.com)
11*4882a593Smuzhiyun */
12*4882a593Smuzhiyun #include <linux/init.h>
13*4882a593Smuzhiyun #include <linux/slab.h>
14*4882a593Smuzhiyun #include <linux/export.h>
15*4882a593Smuzhiyun #include <linux/device.h>
16*4882a593Smuzhiyun #include <linux/spi/spi.h>
17*4882a593Smuzhiyun #include <linux/spi/eeprom.h>
18*4882a593Smuzhiyun #include <asm/txx9/spi.h>
19*4882a593Smuzhiyun
20*4882a593Smuzhiyun #define AT250X0_PAGE_SIZE 8
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun /* register board information for at25 driver */
spi_eeprom_register(int busid,int chipid,int size)23*4882a593Smuzhiyun int __init spi_eeprom_register(int busid, int chipid, int size)
24*4882a593Smuzhiyun {
25*4882a593Smuzhiyun struct spi_board_info info = {
26*4882a593Smuzhiyun .modalias = "at25",
27*4882a593Smuzhiyun .max_speed_hz = 1500000, /* 1.5Mbps */
28*4882a593Smuzhiyun .bus_num = busid,
29*4882a593Smuzhiyun .chip_select = chipid,
30*4882a593Smuzhiyun /* Mode 0: High-Active, Sample-Then-Shift */
31*4882a593Smuzhiyun };
32*4882a593Smuzhiyun struct spi_eeprom *eeprom;
33*4882a593Smuzhiyun eeprom = kzalloc(sizeof(*eeprom), GFP_KERNEL);
34*4882a593Smuzhiyun if (!eeprom)
35*4882a593Smuzhiyun return -ENOMEM;
36*4882a593Smuzhiyun strcpy(eeprom->name, "at250x0");
37*4882a593Smuzhiyun eeprom->byte_len = size;
38*4882a593Smuzhiyun eeprom->page_size = AT250X0_PAGE_SIZE;
39*4882a593Smuzhiyun eeprom->flags = EE_ADDR1;
40*4882a593Smuzhiyun info.platform_data = eeprom;
41*4882a593Smuzhiyun return spi_register_board_info(&info, 1);
42*4882a593Smuzhiyun }
43*4882a593Smuzhiyun
44*4882a593Smuzhiyun /* simple temporary spi driver to provide early access to seeprom. */
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun static struct read_param {
47*4882a593Smuzhiyun int busid;
48*4882a593Smuzhiyun int chipid;
49*4882a593Smuzhiyun int address;
50*4882a593Smuzhiyun unsigned char *buf;
51*4882a593Smuzhiyun int len;
52*4882a593Smuzhiyun } *read_param;
53*4882a593Smuzhiyun
early_seeprom_probe(struct spi_device * spi)54*4882a593Smuzhiyun static int __init early_seeprom_probe(struct spi_device *spi)
55*4882a593Smuzhiyun {
56*4882a593Smuzhiyun int stat = 0;
57*4882a593Smuzhiyun u8 cmd[2];
58*4882a593Smuzhiyun int len = read_param->len;
59*4882a593Smuzhiyun char *buf = read_param->buf;
60*4882a593Smuzhiyun int address = read_param->address;
61*4882a593Smuzhiyun
62*4882a593Smuzhiyun dev_info(&spi->dev, "spiclk %u KHz.\n",
63*4882a593Smuzhiyun (spi->max_speed_hz + 500) / 1000);
64*4882a593Smuzhiyun if (read_param->busid != spi->master->bus_num ||
65*4882a593Smuzhiyun read_param->chipid != spi->chip_select)
66*4882a593Smuzhiyun return -ENODEV;
67*4882a593Smuzhiyun while (len > 0) {
68*4882a593Smuzhiyun /* spi_write_then_read can only work with small chunk */
69*4882a593Smuzhiyun int c = len < AT250X0_PAGE_SIZE ? len : AT250X0_PAGE_SIZE;
70*4882a593Smuzhiyun cmd[0] = 0x03; /* AT25_READ */
71*4882a593Smuzhiyun cmd[1] = address;
72*4882a593Smuzhiyun stat = spi_write_then_read(spi, cmd, sizeof(cmd), buf, c);
73*4882a593Smuzhiyun buf += c;
74*4882a593Smuzhiyun len -= c;
75*4882a593Smuzhiyun address += c;
76*4882a593Smuzhiyun }
77*4882a593Smuzhiyun return stat;
78*4882a593Smuzhiyun }
79*4882a593Smuzhiyun
80*4882a593Smuzhiyun static struct spi_driver early_seeprom_driver __initdata = {
81*4882a593Smuzhiyun .driver = {
82*4882a593Smuzhiyun .name = "at25",
83*4882a593Smuzhiyun },
84*4882a593Smuzhiyun .probe = early_seeprom_probe,
85*4882a593Smuzhiyun };
86*4882a593Smuzhiyun
spi_eeprom_read(int busid,int chipid,int address,unsigned char * buf,int len)87*4882a593Smuzhiyun int __init spi_eeprom_read(int busid, int chipid, int address,
88*4882a593Smuzhiyun unsigned char *buf, int len)
89*4882a593Smuzhiyun {
90*4882a593Smuzhiyun int ret;
91*4882a593Smuzhiyun struct read_param param = {
92*4882a593Smuzhiyun .busid = busid,
93*4882a593Smuzhiyun .chipid = chipid,
94*4882a593Smuzhiyun .address = address,
95*4882a593Smuzhiyun .buf = buf,
96*4882a593Smuzhiyun .len = len
97*4882a593Smuzhiyun };
98*4882a593Smuzhiyun
99*4882a593Smuzhiyun read_param = ¶m;
100*4882a593Smuzhiyun ret = spi_register_driver(&early_seeprom_driver);
101*4882a593Smuzhiyun if (!ret)
102*4882a593Smuzhiyun spi_unregister_driver(&early_seeprom_driver);
103*4882a593Smuzhiyun return ret;
104*4882a593Smuzhiyun }
105