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/init.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/wait.h>
  29 #include <linux/isa.h>
  30 #include <linux/i2c.h>
  31 #include <linux/i2c-algo-pca.h>
  32
  33 #include <asm/io.h>
  34 #include <asm/irq.h>
  35
  36 #define DRIVER "i2c-pca-isa"
  37 #define IO_SIZE 4
  38
  39 static unsigned long base;
  40 static int irq = -1;
  41
  42 /* Data sheet recommends 59kHz for 100kHz operation due to variation
  43  * in the actual clock rate */
  44 static int clock  = I2C_PCA_CON_59kHz;
  45
  46 static wait_queue_head_t pca_wait;
  47
  48 static void pca_isa_writebyte(void *pd, int reg, int val)
  49 {
  50 #ifdef DEBUG_IO
  51         static char *names[] = { "T/O", "DAT", "ADR", "CON" };
  52         printk("*** write %s at %#lx <= %#04x\n", names[reg], base+reg, val);
  53 #endif
  54         outb(val, base+reg);
  55 }
  56
  57 static int pca_isa_readbyte(void *pd, int reg)
  58 {
  59         int res = inb(base+reg);
  60 #ifdef DEBUG_IO
  61         {
  62                 static char *names[] = { "STA", "DAT", "ADR", "CON" };
  63                 printk("*** read  %s => %#04x\n", names[reg], res);
  64         }
  65 #endif
  66         return res;
  67 }
  68
  69 static int pca_isa_waitforcompletion(void *pd)
  70 {
  71         int ret = 0;
  72
  73         if (irq > -1) {
  74                 ret = wait_event_interruptible(pca_wait,
  75                                                pca_isa_readbyte(pd, I2C_PCA_CON) & I2C_PCA_CON_SI);
  76         } else {
  77                 while ((pca_isa_readbyte(pd, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
  78                         udelay(100);
  79         }
  80         return ret;
  81 }
  82
  83 static void pca_isa_resetchip(void *pd)
  84 {
  85         /* apparently only an external reset will do it. not a lot can be done */
  86         printk(KERN_WARNING DRIVER ": Haven't figured out how to do a reset yet\n");
  87 }
  88
  89 static irqreturn_t pca_handler(int this_irq, void *dev_id) {
  90         wake_up_interruptible(&pca_wait);
  91         return IRQ_HANDLED;
  92 }
  93
  94 static struct i2c_algo_pca_data pca_isa_data = {
  95         /* .data intentionally left NULL, not needed with ISA */
  96         .write_byte             = pca_isa_writebyte,
  97         .read_byte              = pca_isa_readbyte,
  98         .wait_for_completion    = pca_isa_waitforcompletion,
  99         .reset_chip             = pca_isa_resetchip,
 100 };
 101
 102 static struct i2c_adapter pca_isa_ops = {
 103         .owner          = THIS_MODULE,
 104         .algo_data      = &pca_isa_data,
 105         .name           = "PCA9564 ISA Adapter",
 106         .timeout        = 100,
 107 };
 108
 109 static int __devinit pca_isa_match(struct device *dev, unsigned int id)
 110 {
 111         int match = base != 0;
 112
 113         if (match) {
 114                 if (irq <= -1)
 115                         dev_warn(dev, "Using polling mode (specify irq)\n");
 116         } else
 117                 dev_err(dev, "Please specify I/O base\n");
 118
 119         return match;
 120 }
 121
 122 static int __devinit pca_isa_probe(struct device *dev, unsigned int id)
 123 {
 124         init_waitqueue_head(&pca_wait);
 125
 126         dev_info(dev, "i/o base %#08lx. irq %d\n", base, irq);
 127
 128 #ifdef CONFIG_PPC
 129         if (check_legacy_ioport(base)) {
 130                 dev_err(dev, "I/O address %#08lx is not available\n", base);
 131                 goto out;
 132         }
 133 #endif
 134
 135         if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
 136                 dev_err(dev, "I/O address %#08lx is in use\n", base);
 137                 goto out;
 138         }
 139
 140         if (irq > -1) {
 141                 if (request_irq(irq, pca_handler, 0, "i2c-pca-isa", &pca_isa_ops) < 0) {
 142                         dev_err(dev, "Request irq%d failed\n", irq);
 143                         goto out_region;
 144                 }
 145         }
 146
 147         pca_isa_data.i2c_clock = clock;
 148         if (i2c_pca_add_bus(&pca_isa_ops) < 0) {
 149                 dev_err(dev, "Failed to add i2c bus\n");
 150                 goto out_irq;
 151         }
 152
 153         return 0;
 154
 155  out_irq:
 156         if (irq > -1)
 157                 free_irq(irq, &pca_isa_ops);
 158  out_region:
 159         release_region(base, IO_SIZE);
 160  out:
 161         return -ENODEV;
 162 }
 163
 164 static int __devexit pca_isa_remove(struct device *dev, unsigned int id)
 165 {
 166         i2c_del_adapter(&pca_isa_ops);
 167
 168         if (irq > -1) {
 169                 disable_irq(irq);
 170                 free_irq(irq, &pca_isa_ops);
 171         }
 172         release_region(base, IO_SIZE);
 173
 174         return 0;
 175 }
 176
 177 static struct isa_driver pca_isa_driver = {
 178         .match          = pca_isa_match,
 179         .probe          = pca_isa_probe,
 180         .remove         = __devexit_p(pca_isa_remove),
 181         .driver = {
 182                 .owner  = THIS_MODULE,
 183                 .name   = DRIVER,
 184         }
 185 };
 186
 187 static int __init pca_isa_init(void)
 188 {
 189         return isa_register_driver(&pca_isa_driver, 1);
 190 }
 191
 192 static void __exit pca_isa_exit(void)
 193 {
 194         isa_unregister_driver(&pca_isa_driver);
 195 }
 196
 197 MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
 198 MODULE_DESCRIPTION("ISA base PCA9564 driver");
 199 MODULE_LICENSE("GPL");
 200
 201 module_param(base, ulong, 0);
 202 MODULE_PARM_DESC(base, "I/O base address");
 203
 204 module_param(irq, int, 0);
 205 MODULE_PARM_DESC(irq, "IRQ");
 206 module_param(clock, int, 0);
 207 MODULE_PARM_DESC(clock, "Clock rate as described in table 1 of PCA9564 datasheet");
 208
 209 module_init(pca_isa_init);
 210 module_exit(pca_isa_exit);