drivers/i2c/busses/i2c-pca-isa.c

   1 /*
   2  *  i2c-pca-isa.c driver for PCA9564 on ISA boards
   3  *    Copyright (C) 2004 Arcom Control Systems
   4  *    Copyright (C) 2008 Pengutronix
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21 #include <linux/kernel.h>
  22 #include <linux/ioport.h>
  23 #include <linux/module.h>
  24 #include <linux/moduleparam.h>
  25 #include <linux/delay.h>
  26 #include <linux/jiffies.h>
  27 #include <linux/init.h>
  28 #include <linux/interrupt.h>
  29 #include <linux/wait.h>
  30 #include <linux/isa.h>
  31 #include <linux/i2c.h>
  32 #include <linux/i2c-algo-pca.h>
  33 #include <linux/io.h>
  34
  35 #include <asm/irq.h>
  36
  37 #define DRIVER "i2c-pca-isa"
  38 #define IO_SIZE 4
  39
  40 static unsigned long base;
  41 static int irq = -1;
  42
  43 /* Data sheet recommends 59kHz for 100kHz operation due to variation
  44  * in the actual clock rate */
  45 static int clock  = 59000;
  46
  47 static struct i2c_adapter pca_isa_ops;
  48 static wait_queue_head_t pca_wait;
  49
  50 static void pca_isa_writebyte(void *pd, int reg, int val)
  51 {
  52 #ifdef DEBUG_IO
  53         static char *names[] = { "T/O", "DAT", "ADR", "CON" };
  54         printk(KERN_DEBUG "*** write %s at %#lx <= %#04x\n", names[reg],
  55                base+reg, val);
  56 #endif
  57         outb(val, base+reg);
  58 }
  59
  60 static int pca_isa_readbyte(void *pd, int reg)
  61 {
  62         int res = inb(base+reg);
  63 #ifdef DEBUG_IO
  64         {
  65                 static char *names[] = { "STA", "DAT", "ADR", "CON" };
  66                 printk(KERN_DEBUG "*** read  %s => %#04x\n", names[reg], res);
  67         }
  68 #endif
  69         return res;
  70 }
  71
  72 static int pca_isa_waitforcompletion(void *pd)
  73 {
  74         unsigned long timeout;
  75         long ret;
  76
  77         if (irq > -1) {
  78                 ret = wait_event_timeout(pca_wait,
  79                                 pca_isa_readbyte(pd, I2C_PCA_CON)
  80                                 & I2C_PCA_CON_SI, pca_isa_ops.timeout);
  81         } else {
  82                 /* Do polling */
  83                 timeout = jiffies + pca_isa_ops.timeout;
  84                 do {
  85                         ret = time_before(jiffies, timeout);
  86                         if (pca_isa_readbyte(pd, I2C_PCA_CON)
  87                                         & I2C_PCA_CON_SI)
  88                                 break;
  89                         udelay(100);
  90                 } while (ret);
  91         }
  92
  93         return ret > 0;
  94 }
  95
  96 static void pca_isa_resetchip(void *pd)
  97 {
  98         /* apparently only an external reset will do it. not a lot can be done */
  99         printk(KERN_WARNING DRIVER ": Haven't figured out how to do a reset yet\n");
 100 }
 101
 102 static irqreturn_t pca_handler(int this_irq, void *dev_id) {
 103         wake_up(&pca_wait);
 104         return IRQ_HANDLED;
 105 }
 106
 107 static struct i2c_algo_pca_data pca_isa_data = {
 108         /* .data intentionally left NULL, not needed with ISA */
 109         .write_byte             = pca_isa_writebyte,
 110         .read_byte              = pca_isa_readbyte,
 111         .wait_for_completion    = pca_isa_waitforcompletion,
 112         .reset_chip             = pca_isa_resetchip,
 113 };
 114
 115 static struct i2c_adapter pca_isa_ops = {
 116         .owner          = THIS_MODULE,
 117         .algo_data      = &pca_isa_data,
 118         .name           = "PCA9564/PCA9665 ISA Adapter",
 119         .timeout        = HZ,
 120 };
 121
 122 static int pca_isa_match(struct device *dev, unsigned int id)
 123 {
 124         int match = base != 0;
 125
 126         if (match) {
 127                 if (irq <= -1)
 128                         dev_warn(dev, "Using polling mode (specify irq)\n");
 129         } else
 130                 dev_err(dev, "Please specify I/O base\n");
 131
 132         return match;
 133 }
 134
 135 static int pca_isa_probe(struct device *dev, unsigned int id)
 136 {
 137         init_waitqueue_head(&pca_wait);
 138
 139         dev_info(dev, "i/o base %#08lx. irq %d\n", base, irq);
 140
 141 #ifdef CONFIG_PPC
 142         if (check_legacy_ioport(base)) {
 143                 dev_err(dev, "I/O address %#08lx is not available\n", base);
 144                 goto out;
 145         }
 146 #endif
 147
 148         if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
 149                 dev_err(dev, "I/O address %#08lx is in use\n", base);
 150                 goto out;
 151         }
 152
 153         if (irq > -1) {
 154                 if (request_irq(irq, pca_handler, 0, "i2c-pca-isa", &pca_isa_ops) < 0) {
 155                         dev_err(dev, "Request irq%d failed\n", irq);
 156                         goto out_region;
 157                 }
 158         }
 159
 160         pca_isa_data.i2c_clock = clock;
 161         if (i2c_pca_add_bus(&pca_isa_ops) < 0) {
 162                 dev_err(dev, "Failed to add i2c bus\n");
 163                 goto out_irq;
 164         }
 165
 166         return 0;
 167
 168  out_irq:
 169         if (irq > -1)
 170                 free_irq(irq, &pca_isa_ops);
 171  out_region:
 172         release_region(base, IO_SIZE);
 173  out:
 174         return -ENODEV;
 175 }
 176
 177 static int pca_isa_remove(struct device *dev, unsigned int id)
 178 {
 179         i2c_del_adapter(&pca_isa_ops);
 180
 181         if (irq > -1) {
 182                 disable_irq(irq);
 183                 free_irq(irq, &pca_isa_ops);
 184         }
 185         release_region(base, IO_SIZE);
 186
 187         return 0;
 188 }
 189
 190 static struct isa_driver pca_isa_driver = {
 191         .match          = pca_isa_match,
 192         .probe          = pca_isa_probe,
 193         .remove         = pca_isa_remove,
 194         .driver = {
 195                 .owner  = THIS_MODULE,
 196                 .name   = DRIVER,
 197         }
 198 };
 199
 200 static int __init pca_isa_init(void)
 201 {
 202         return isa_register_driver(&pca_isa_driver, 1);
 203 }
 204
 205 static void __exit pca_isa_exit(void)
 206 {
 207         isa_unregister_driver(&pca_isa_driver);
 208 }
 209
 210 MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
 211 MODULE_DESCRIPTION("ISA base PCA9564/PCA9665 driver");
 212 MODULE_LICENSE("GPL");
 213
 214 module_param(base, ulong, 0);
 215 MODULE_PARM_DESC(base, "I/O base address");
 216
 217 module_param(irq, int, 0);
 218 MODULE_PARM_DESC(irq, "IRQ");
 219 module_param(clock, int, 0);
 220 MODULE_PARM_DESC(clock, "Clock rate in hertz.\n\t\t"
 221                 "For PCA9564: 330000,288000,217000,146000,"
 222                 "88000,59000,44000,36000\n"
 223                 "\t\tFor PCA9665:\tStandard: 60300 - 100099\n"
 224                 "\t\t\t\tFast: 100100 - 400099\n"
 225                 "\t\t\t\tFast+: 400100 - 10000099\n"
 226                 "\t\t\t\tTurbo: Up to 1265800");
 227
 228 module_init(pca_isa_init);
 229 module_exit(pca_isa_exit);