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 */
23int __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
46static struct read_param {
47	int busid;
48	int chipid;
49	int address;
50	unsigned char *buf;
51	int len;
52} *read_param;
53
54static 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
80static struct spi_driver early_seeprom_driver __initdata = {
81	.driver = {
82		.name	= "at25",
83		.owner	= THIS_MODULE,
84	},
85	.probe	= early_seeprom_probe,
86};
87
88int __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}
106