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/config.h>
  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/slab.h>
  27 #include <linux/init.h>
  28 #include <linux/interrupt.h>
  29 #include <linux/pci.h>
  30 #include <linux/wait.h>
  31
  32 #include <linux/i2c.h>
  33 #include <linux/i2c-algo-pca.h>
  34
  35 #include <asm/io.h>
  36 #include <asm/irq.h>
  37
  38 #include "../algos/i2c-algo-pca.h"
  39
  40 #define IO_SIZE 4
  41
  42 #undef DEBUG_IO
  43 //#define DEBUG_IO
  44
  45 static unsigned long base   = 0x330;
  46 static int irq    = 10;
  47
  48 /* Data sheet recommends 59kHz for 100kHz operation due to variation
  49  * in the actual clock rate */
  50 static int clock  = I2C_PCA_CON_59kHz;
  51
  52 static int own    = 0x55;
  53
  54 static wait_queue_head_t pca_wait;
  55
  56 static int pca_isa_getown(struct i2c_algo_pca_data *adap)
  57 {
  58         return (own);
  59 }
  60
  61 static int pca_isa_getclock(struct i2c_algo_pca_data *adap)
  62 {
  63         return (clock);
  64 }
  65
  66 static void
  67 pca_isa_writebyte(struct i2c_algo_pca_data *adap, int reg, int val)
  68 {
  69 #ifdef DEBUG_IO
  70         static char *names[] = { "T/O", "DAT", "ADR", "CON" };
  71         printk("*** write %s at %#lx <= %#04x\n", names[reg], base+reg, val);
  72 #endif
  73         outb(val, base+reg);
  74 }
  75
  76 static int
  77 pca_isa_readbyte(struct i2c_algo_pca_data *adap, int reg)
  78 {
  79         int res = inb(base+reg);
  80 #ifdef DEBUG_IO
  81         {
  82                 static char *names[] = { "STA", "DAT", "ADR", "CON" };
  83                 printk("*** read  %s => %#04x\n", names[reg], res);
  84         }
  85 #endif
  86         return res;
  87 }
  88
  89 static int pca_isa_waitforinterrupt(struct i2c_algo_pca_data *adap)
  90 {
  91         int ret = 0;
  92
  93         if (irq > -1) {
  94                 ret = wait_event_interruptible(pca_wait,
  95                                                pca_isa_readbyte(adap, I2C_PCA_CON) & I2C_PCA_CON_SI);
  96         } else {
  97                 while ((pca_isa_readbyte(adap, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
  98                         udelay(100);
  99         }
 100         return ret;
 101 }
 102
 103 static irqreturn_t pca_handler(int this_irq, void *dev_id, struct pt_regs *regs) {
 104         wake_up_interruptible(&pca_wait);
 105         return IRQ_HANDLED;
 106 }
 107
 108 static struct i2c_algo_pca_data pca_isa_data = {
 109         .get_own                = pca_isa_getown,
 110         .get_clock              = pca_isa_getclock,
 111         .write_byte             = pca_isa_writebyte,
 112         .read_byte              = pca_isa_readbyte,
 113         .wait_for_interrupt     = pca_isa_waitforinterrupt,
 114 };
 115
 116 static struct i2c_adapter pca_isa_ops = {
 117         .owner          = THIS_MODULE,
 118         .id             = I2C_HW_A_ISA,
 119         .algo_data      = &pca_isa_data,
 120         .name           = "PCA9564 ISA Adapter",
 121 };
 122
 123 static int __init pca_isa_init(void)
 124 {
 125
 126         init_waitqueue_head(&pca_wait);
 127
 128         printk(KERN_INFO "i2c-pca-isa: i/o base %#08lx. irq %d\n", base, irq);
 129
 130         if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
 131                 printk(KERN_ERR "i2c-pca-isa: I/O address %#08lx is in use.\n", base);
 132                 goto out;
 133         }
 134
 135         if (irq > -1) {
 136                 if (request_irq(irq, pca_handler, 0, "i2c-pca-isa", &pca_isa_ops) < 0) {
 137                         printk(KERN_ERR "i2c-pca-isa: Request irq%d failed\n", irq);
 138                         goto out_region;
 139                 }
 140         }
 141
 142         if (i2c_pca_add_bus(&pca_isa_ops) < 0) {
 143                 printk(KERN_ERR "i2c-pca-isa: Failed to add i2c bus\n");
 144                 goto out_irq;
 145         }
 146
 147         return 0;
 148
 149  out_irq:
 150         if (irq > -1)
 151                 free_irq(irq, &pca_isa_ops);
 152  out_region:
 153         release_region(base, IO_SIZE);
 154  out:
 155         return -ENODEV;
 156 }
 157
 158 static void pca_isa_exit(void)
 159 {
 160         i2c_pca_del_bus(&pca_isa_ops);
 161
 162         if (irq > 0) {
 163                 disable_irq(irq);
 164                 free_irq(irq, &pca_isa_ops);
 165         }
 166         release_region(base, IO_SIZE);
 167 }
 168
 169 MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
 170 MODULE_DESCRIPTION("ISA base PCA9564 driver");
 171 MODULE_LICENSE("GPL");
 172
 173 module_param(base, ulong, 0);
 174 MODULE_PARM_DESC(base, "I/O base address");
 175
 176 module_param(irq, int, 0);
 177 MODULE_PARM_DESC(irq, "IRQ");
 178 module_param(clock, int, 0);
 179 MODULE_PARM_DESC(clock, "Clock rate as described in table 1 of PCA9564 datasheet");
 180
 181 module_param(own, int, 0); /* the driver can't do slave mode, so there's no real point in this */
 182
 183 module_init(pca_isa_init);
 184 module_exit(pca_isa_exit);