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  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19
  20 #include <linux/kernel.h>
  21 #include <linux/ioport.h>
  22 #include <linux/module.h>
  23 #include <linux/moduleparam.h>
  24 #include <linux/delay.h>
  25 #include <linux/slab.h>
  26 #include <linux/init.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/pci.h>
  29 #include <linux/wait.h>
  30
  31 #include <linux/i2c.h>
  32 #include <linux/i2c-algo-pca.h>
  33
  34 #include <asm/io.h>
  35 #include <asm/irq.h>
  36
  37 #include "../algos/i2c-algo-pca.h"
  38
  39 #define IO_SIZE 4
  40
  41 #undef DEBUG_IO
  42 //#define DEBUG_IO
  43
  44 static unsigned long base   = 0x330;
  45 static int irq    = 10;
  46
  47 /* Data sheet recommends 59kHz for 100kHz operation due to variation
  48  * in the actual clock rate */
  49 static int clock  = I2C_PCA_CON_59kHz;
  50
  51 static int own    = 0x55;
  52
  53 static wait_queue_head_t pca_wait;
  54
  55 static int pca_isa_getown(struct i2c_algo_pca_data *adap)
  56 {
  57         return (own);
  58 }
  59
  60 static int pca_isa_getclock(struct i2c_algo_pca_data *adap)
  61 {
  62         return (clock);
  63 }
  64
  65 static void
  66 pca_isa_writebyte(struct i2c_algo_pca_data *adap, int reg, int val)
  67 {
  68 #ifdef DEBUG_IO
  69         static char *names[] = { "T/O", "DAT", "ADR", "CON" };
  70         printk("*** write %s at %#lx <= %#04x\n", names[reg], base+reg, val);
  71 #endif
  72         outb(val, base+reg);
  73 }
  74
  75 static int
  76 pca_isa_readbyte(struct i2c_algo_pca_data *adap, int reg)
  77 {
  78         int res = inb(base+reg);
  79 #ifdef DEBUG_IO
  80         {
  81                 static char *names[] = { "STA", "DAT", "ADR", "CON" };
  82                 printk("*** read  %s => %#04x\n", names[reg], res);
  83         }
  84 #endif
  85         return res;
  86 }
  87
  88 static int pca_isa_waitforinterrupt(struct i2c_algo_pca_data *adap)
  89 {
  90         int ret = 0;
  91
  92         if (irq > -1) {
  93                 ret = wait_event_interruptible(pca_wait,
  94                                                pca_isa_readbyte(adap, I2C_PCA_CON) & I2C_PCA_CON_SI);
  95         } else {
  96                 while ((pca_isa_readbyte(adap, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
  97                         udelay(100);
  98         }
  99         return ret;
 100 }
 101
 102 static irqreturn_t pca_handler(int this_irq, void *dev_id, struct pt_regs *regs) {
 103         wake_up_interruptible(&pca_wait);
 104         return IRQ_HANDLED;
 105 }
 106
 107 static struct i2c_algo_pca_data pca_isa_data = {
 108         .get_own                = pca_isa_getown,
 109         .get_clock              = pca_isa_getclock,
 110         .write_byte             = pca_isa_writebyte,
 111         .read_byte              = pca_isa_readbyte,
 112         .wait_for_interrupt     = pca_isa_waitforinterrupt,
 113 };
 114
 115 static struct i2c_adapter pca_isa_ops = {
 116         .owner          = THIS_MODULE,
 117         .id             = I2C_HW_A_ISA,
 118         .algo_data      = &pca_isa_data,
 119         .name           = "PCA9564 ISA Adapter",
 120 };
 121
 122 static int __init pca_isa_init(void)
 123 {
 124
 125         init_waitqueue_head(&pca_wait);
 126
 127         printk(KERN_INFO "i2c-pca-isa: i/o base %#08lx. irq %d\n", base, irq);
 128
 129         if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
 130                 printk(KERN_ERR "i2c-pca-isa: I/O address %#08lx is in use.\n", base);
 131                 goto out;
 132         }
 133
 134         if (irq > -1) {
 135                 if (request_irq(irq, pca_handler, 0, "i2c-pca-isa", &pca_isa_ops) < 0) {
 136                         printk(KERN_ERR "i2c-pca-isa: Request irq%d failed\n", irq);
 137                         goto out_region;
 138                 }
 139         }
 140
 141         if (i2c_pca_add_bus(&pca_isa_ops) < 0) {
 142                 printk(KERN_ERR "i2c-pca-isa: Failed to add i2c bus\n");
 143                 goto out_irq;
 144         }
 145
 146         return 0;
 147
 148  out_irq:
 149         if (irq > -1)
 150                 free_irq(irq, &pca_isa_ops);
 151  out_region:
 152         release_region(base, IO_SIZE);
 153  out:
 154         return -ENODEV;
 155 }
 156
 157 static void pca_isa_exit(void)
 158 {
 159         i2c_pca_del_bus(&pca_isa_ops);
 160
 161         if (irq > 0) {
 162                 disable_irq(irq);
 163                 free_irq(irq, &pca_isa_ops);
 164         }
 165         release_region(base, IO_SIZE);
 166 }
 167
 168 MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
 169 MODULE_DESCRIPTION("ISA base PCA9564 driver");
 170 MODULE_LICENSE("GPL");
 171
 172 module_param(base, ulong, 0);
 173 MODULE_PARM_DESC(base, "I/O base address");
 174
 175 module_param(irq, int, 0);
 176 MODULE_PARM_DESC(irq, "IRQ");
 177 module_param(clock, int, 0);
 178 MODULE_PARM_DESC(clock, "Clock rate as described in table 1 of PCA9564 datasheet");
 179
 180 module_param(own, int, 0); /* the driver can't do slave mode, so there's no real point in this */
 181
 182 module_init(pca_isa_init);
 183 module_exit(pca_isa_exit);