arch/mips/tx4938/toshiba_rbtx4938/spi_eeprom.c

   1 /*
   2  * linux/arch/mips/tx4938/toshiba_rbtx4938/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/delay.h>
  14 #include <linux/proc_fs.h>
  15 #include <linux/spinlock.h>
  16 #include <asm/tx4938/spi.h>
  17 #include <asm/tx4938/tx4938.h>
  18
  19 /* ATMEL 250x0 instructions */
  20 #define ATMEL_WREN      0x06
  21 #define ATMEL_WRDI      0x04
  22 #define ATMEL_RDSR      0x05
  23 #define ATMEL_WRSR      0x01
  24 #define ATMEL_READ      0x03
  25 #define ATMEL_WRITE     0x02
  26
  27 #define ATMEL_SR_BSY    0x01
  28 #define ATMEL_SR_WEN    0x02
  29 #define ATMEL_SR_BP0    0x04
  30 #define ATMEL_SR_BP1    0x08
  31
  32 DEFINE_SPINLOCK(spi_eeprom_lock);
  33
  34 static struct spi_dev_desc seeprom_dev_desc = {
  35         .baud           = 1500000,      /* 1.5Mbps */
  36         .tcss           = 1,
  37         .tcsh           = 1,
  38         .tcsr           = 1,
  39         .byteorder      = 1,            /* MSB-First */
  40         .polarity       = 0,            /* High-Active */
  41         .phase          = 0,            /* Sample-Then-Shift */
  42
  43 };
  44 static inline int
  45 spi_eeprom_io(int chipid,
  46               unsigned char **inbufs, unsigned int *incounts,
  47               unsigned char **outbufs, unsigned int *outcounts)
  48 {
  49         return txx9_spi_io(chipid, &seeprom_dev_desc,
  50                            inbufs, incounts, outbufs, outcounts, 0);
  51 }
  52
  53 int spi_eeprom_write_enable(int chipid, int enable)
  54 {
  55         unsigned char inbuf[1];
  56         unsigned char *inbufs[1];
  57         unsigned int incounts[2];
  58         unsigned long flags;
  59         int stat;
  60         inbuf[0] = enable ? ATMEL_WREN : ATMEL_WRDI;
  61         inbufs[0] = inbuf;
  62         incounts[0] = sizeof(inbuf);
  63         incounts[1] = 0;
  64         spin_lock_irqsave(&spi_eeprom_lock, flags);
  65         stat = spi_eeprom_io(chipid, inbufs, incounts, NULL, NULL);
  66         spin_unlock_irqrestore(&spi_eeprom_lock, flags);
  67         return stat;
  68 }
  69
  70 static int spi_eeprom_read_status_nolock(int chipid)
  71 {
  72         unsigned char inbuf[2], outbuf[2];
  73         unsigned char *inbufs[1], *outbufs[1];
  74         unsigned int incounts[2], outcounts[2];
  75         int stat;
  76         inbuf[0] = ATMEL_RDSR;
  77         inbuf[1] = 0;
  78         inbufs[0] = inbuf;
  79         incounts[0] = sizeof(inbuf);
  80         incounts[1] = 0;
  81         outbufs[0] = outbuf;
  82         outcounts[0] = sizeof(outbuf);
  83         outcounts[1] = 0;
  84         stat = spi_eeprom_io(chipid, inbufs, incounts, outbufs, outcounts);
  85         if (stat < 0)
  86                 return stat;
  87         return outbuf[1];
  88 }
  89
  90 int spi_eeprom_read_status(int chipid)
  91 {
  92         unsigned long flags;
  93         int stat;
  94         spin_lock_irqsave(&spi_eeprom_lock, flags);
  95         stat = spi_eeprom_read_status_nolock(chipid);
  96         spin_unlock_irqrestore(&spi_eeprom_lock, flags);
  97         return stat;
  98 }
  99
 100 int spi_eeprom_read(int chipid, int address, unsigned char *buf, int len)
 101 {
 102         unsigned char inbuf[2];
 103         unsigned char *inbufs[2], *outbufs[2];
 104         unsigned int incounts[2], outcounts[3];
 105         unsigned long flags;
 106         int stat;
 107         inbuf[0] = ATMEL_READ;
 108         inbuf[1] = address;
 109         inbufs[0] = inbuf;
 110         inbufs[1] = NULL;
 111         incounts[0] = sizeof(inbuf);
 112         incounts[1] = 0;
 113         outbufs[0] = NULL;
 114         outbufs[1] = buf;
 115         outcounts[0] = 2;
 116         outcounts[1] = len;
 117         outcounts[2] = 0;
 118         spin_lock_irqsave(&spi_eeprom_lock, flags);
 119         stat = spi_eeprom_io(chipid, inbufs, incounts, outbufs, outcounts);
 120         spin_unlock_irqrestore(&spi_eeprom_lock, flags);
 121         return stat;
 122 }
 123
 124 int spi_eeprom_write(int chipid, int address, unsigned char *buf, int len)
 125 {
 126         unsigned char inbuf[2];
 127         unsigned char *inbufs[2];
 128         unsigned int incounts[3];
 129         unsigned long flags;
 130         int i, stat;
 131
 132         if (address / 8 != (address + len - 1) / 8)
 133                 return -EINVAL;
 134         stat = spi_eeprom_write_enable(chipid, 1);
 135         if (stat < 0)
 136                 return stat;
 137         stat = spi_eeprom_read_status(chipid);
 138         if (stat < 0)
 139                 return stat;
 140         if (!(stat & ATMEL_SR_WEN))
 141                 return -EPERM;
 142
 143         inbuf[0] = ATMEL_WRITE;
 144         inbuf[1] = address;
 145         inbufs[0] = inbuf;
 146         inbufs[1] = buf;
 147         incounts[0] = sizeof(inbuf);
 148         incounts[1] = len;
 149         incounts[2] = 0;
 150         spin_lock_irqsave(&spi_eeprom_lock, flags);
 151         stat = spi_eeprom_io(chipid, inbufs, incounts, NULL, NULL);
 152         if (stat < 0)
 153                 goto unlock_return;
 154
 155         /* write start.  max 10ms */
 156         for (i = 10; i > 0; i--) {
 157                 int stat = spi_eeprom_read_status_nolock(chipid);
 158                 if (stat < 0)
 159                         goto unlock_return;
 160                 if (!(stat & ATMEL_SR_BSY))
 161                         break;
 162                 mdelay(1);
 163         }
 164         spin_unlock_irqrestore(&spi_eeprom_lock, flags);
 165         if (i == 0)
 166                 return -EIO;
 167         return len;
 168  unlock_return:
 169         spin_unlock_irqrestore(&spi_eeprom_lock, flags);
 170         return stat;
 171 }
 172
 173 #ifdef CONFIG_PROC_FS
 174 #define MAX_SIZE        0x80    /* for ATMEL 25010 */
 175 static int spi_eeprom_read_proc(char *page, char **start, off_t off,
 176                                 int count, int *eof, void *data)
 177 {
 178         unsigned int size = MAX_SIZE;
 179         if (spi_eeprom_read((int)data, 0, (unsigned char *)page, size) < 0)
 180                 size = 0;
 181         return size;
 182 }
 183
 184 static int spi_eeprom_write_proc(struct file *file, const char *buffer,
 185                                  unsigned long count, void *data)
 186 {
 187         unsigned int size = MAX_SIZE;
 188         int i;
 189         if (file->f_pos >= size)
 190                 return -EIO;
 191         if (file->f_pos + count > size)
 192                 count = size - file->f_pos;
 193         for (i = 0; i < count; i += 8) {
 194                 int len = count - i < 8 ? count - i : 8;
 195                 if (spi_eeprom_write((int)data, file->f_pos,
 196                                      (unsigned char *)buffer, len) < 0) {
 197                         count = -EIO;
 198                         break;
 199                 }
 200                 buffer += len;
 201                 file->f_pos += len;
 202         }
 203         return count;
 204 }
 205
 206 __init void spi_eeprom_proc_create(struct proc_dir_entry *dir, int chipid)
 207 {
 208         struct proc_dir_entry *entry;
 209         char name[128];
 210         sprintf(name, "seeprom-%d", chipid);
 211         entry = create_proc_entry(name, 0600, dir);
 212         if (entry) {
 213                 entry->read_proc = spi_eeprom_read_proc;
 214                 entry->write_proc = spi_eeprom_write_proc;
 215                 entry->data = (void *)chipid;
 216         }
 217 }
 218 #endif /* CONFIG_PROC_FS */