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
  17 #include <linux/kernel.h>
  18 #include <linux/ioport.h>
  19 #include <linux/module.h>
  20 #include <linux/moduleparam.h>
  21 #include <linux/delay.h>
  22 #include <linux/jiffies.h>
  23 #include <linux/init.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/wait.h>
  26 #include <linux/isa.h>
  27 #include <linux/i2c.h>
  28 #include <linux/i2c-algo-pca.h>
  29 #include <linux/io.h>
  30
  31 #include <asm/irq.h>
  32
  33 #define DRIVER "i2c-pca-isa"
  34 #define IO_SIZE 4
  35
  36 static unsigned long base;
  37 static int irq = -1;
  38
  39 /* Data sheet recommends 59kHz for 100kHz operation due to variation
  40  * in the actual clock rate */
  41 static int clock  = 59000;
  42
  43 static struct i2c_adapter pca_isa_ops;
  44 static wait_queue_head_t pca_wait;
  45
  46 static void pca_isa_writebyte(void *pd, int reg, int val)
  47 {
  48 #ifdef DEBUG_IO
  49         static char *names[] = { "T/O", "DAT", "ADR", "CON" };
  50         printk(KERN_DEBUG "*** write %s at %#lx <= %#04x\n", names[reg],
  51                base+reg, val);
  52 #endif
  53         outb(val, base+reg);
  54 }
  55
  56 static int pca_isa_readbyte(void *pd, int reg)
  57 {
  58         int res = inb(base+reg);
  59 #ifdef DEBUG_IO
  60         {
  61                 static char *names[] = { "STA", "DAT", "ADR", "CON" };
  62                 printk(KERN_DEBUG "*** read  %s => %#04x\n", names[reg], res);
  63         }
  64 #endif
  65         return res;
  66 }
  67
  68 static int pca_isa_waitforcompletion(void *pd)
  69 {
  70         unsigned long timeout;
  71         long ret;
  72
  73         if (irq > -1) {
  74                 ret = wait_event_timeout(pca_wait,
  75                                 pca_isa_readbyte(pd, I2C_PCA_CON)
  76                                 & I2C_PCA_CON_SI, pca_isa_ops.timeout);
  77         } else {
  78                 /* Do polling */
  79                 timeout = jiffies + pca_isa_ops.timeout;
  80                 do {
  81                         ret = time_before(jiffies, timeout);
  82                         if (pca_isa_readbyte(pd, I2C_PCA_CON)
  83                                         & I2C_PCA_CON_SI)
  84                                 break;
  85                         udelay(100);
  86                 } while (ret);
  87         }
  88
  89         return ret > 0;
  90 }
  91
  92 static void pca_isa_resetchip(void *pd)
  93 {
  94         /* apparently only an external reset will do it. not a lot can be done */
  95         printk(KERN_WARNING DRIVER ": Haven't figured out how to do a reset yet\n");
  96 }
  97
  98 static irqreturn_t pca_handler(int this_irq, void *dev_id) {
  99         wake_up(&pca_wait);
 100         return IRQ_HANDLED;
 101 }
 102
 103 static struct i2c_algo_pca_data pca_isa_data = {
 104         /* .data intentionally left NULL, not needed with ISA */
 105         .write_byte             = pca_isa_writebyte,
 106         .read_byte              = pca_isa_readbyte,
 107         .wait_for_completion    = pca_isa_waitforcompletion,
 108         .reset_chip             = pca_isa_resetchip,
 109 };
 110
 111 static struct i2c_adapter pca_isa_ops = {
 112         .owner          = THIS_MODULE,
 113         .algo_data      = &pca_isa_data,
 114         .name           = "PCA9564/PCA9665 ISA Adapter",
 115         .timeout        = HZ,
 116 };
 117
 118 static int pca_isa_match(struct device *dev, unsigned int id)
 119 {
 120         int match = base != 0;
 121
 122         if (match) {
 123                 if (irq <= -1)
 124                         dev_warn(dev, "Using polling mode (specify irq)\n");
 125         } else
 126                 dev_err(dev, "Please specify I/O base\n");
 127
 128         return match;
 129 }
 130
 131 static int pca_isa_probe(struct device *dev, unsigned int id)
 132 {
 133         init_waitqueue_head(&pca_wait);
 134
 135         dev_info(dev, "i/o base %#08lx. irq %d\n", base, irq);
 136
 137 #ifdef CONFIG_PPC
 138         if (check_legacy_ioport(base)) {
 139                 dev_err(dev, "I/O address %#08lx is not available\n", base);
 140                 goto out;
 141         }
 142 #endif
 143
 144         if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
 145                 dev_err(dev, "I/O address %#08lx is in use\n", base);
 146                 goto out;
 147         }
 148
 149         if (irq > -1) {
 150                 if (request_irq(irq, pca_handler, 0, "i2c-pca-isa", &pca_isa_ops) < 0) {
 151                         dev_err(dev, "Request irq%d failed\n", irq);
 152                         goto out_region;
 153                 }
 154         }
 155
 156         pca_isa_data.i2c_clock = clock;
 157         if (i2c_pca_add_bus(&pca_isa_ops) < 0) {
 158                 dev_err(dev, "Failed to add i2c bus\n");
 159                 goto out_irq;
 160         }
 161
 162         return 0;
 163
 164  out_irq:
 165         if (irq > -1)
 166                 free_irq(irq, &pca_isa_ops);
 167  out_region:
 168         release_region(base, IO_SIZE);
 169  out:
 170         return -ENODEV;
 171 }
 172
 173 static int pca_isa_remove(struct device *dev, unsigned int id)
 174 {
 175         i2c_del_adapter(&pca_isa_ops);
 176
 177         if (irq > -1) {
 178                 disable_irq(irq);
 179                 free_irq(irq, &pca_isa_ops);
 180         }
 181         release_region(base, IO_SIZE);
 182
 183         return 0;
 184 }
 185
 186 static struct isa_driver pca_isa_driver = {
 187         .match          = pca_isa_match,
 188         .probe          = pca_isa_probe,
 189         .remove         = pca_isa_remove,
 190         .driver = {
 191                 .owner  = THIS_MODULE,
 192                 .name   = DRIVER,
 193         }
 194 };
 195
 196 MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
 197 MODULE_DESCRIPTION("ISA base PCA9564/PCA9665 driver");
 198 MODULE_LICENSE("GPL");
 199
 200 module_param(base, ulong, 0);
 201 MODULE_PARM_DESC(base, "I/O base address");
 202 module_param(irq, int, 0);
 203 MODULE_PARM_DESC(irq, "IRQ");
 204 module_param(clock, int, 0);
 205 MODULE_PARM_DESC(clock, "Clock rate in hertz.\n\t\t"
 206                 "For PCA9564: 330000,288000,217000,146000,"
 207                 "88000,59000,44000,36000\n"
 208                 "\t\tFor PCA9665:\tStandard: 60300 - 100099\n"
 209                 "\t\t\t\tFast: 100100 - 400099\n"
 210                 "\t\t\t\tFast+: 400100 - 10000099\n"
 211                 "\t\t\t\tTurbo: Up to 1265800");
 212 module_isa_driver(pca_isa_driver, 1);