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); 184