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 = 0x330; 40 static int irq = 10; 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 .id = I2C_HW_A_ISA, 105 .algo_data = &pca_isa_data, 106 .name = "PCA9564 ISA Adapter", 107 .timeout = 100, 108 }; 109 110 static int __devinit pca_isa_probe(struct device *dev, unsigned int id) 111 { 112 init_waitqueue_head(&pca_wait); 113 114 dev_info(dev, "i/o base %#08lx. irq %d\n", base, irq); 115 116 #ifdef CONFIG_PPC_MERGE 117 if (check_legacy_ioport(base)) { 118 dev_err(dev, "I/O address %#08lx is not available\n", base); 119 goto out; 120 } 121 #endif 122 123 if (!request_region(base, IO_SIZE, "i2c-pca-isa")) { 124 dev_err(dev, "I/O address %#08lx is in use\n", base); 125 goto out; 126 } 127 128 if (irq > -1) { 129 if (request_irq(irq, pca_handler, 0, "i2c-pca-isa", &pca_isa_ops) < 0) { 130 dev_err(dev, "Request irq%d failed\n", irq); 131 goto out_region; 132 } 133 } 134 135 pca_isa_data.i2c_clock = clock; 136 if (i2c_pca_add_bus(&pca_isa_ops) < 0) { 137 dev_err(dev, "Failed to add i2c bus\n"); 138 goto out_irq; 139 } 140 141 return 0; 142 143 out_irq: 144 if (irq > -1) 145 free_irq(irq, &pca_isa_ops); 146 out_region: 147 release_region(base, IO_SIZE); 148 out: 149 return -ENODEV; 150 } 151 152 static int __devexit pca_isa_remove(struct device *dev, unsigned int id) 153 { 154 i2c_del_adapter(&pca_isa_ops); 155 156 if (irq > 0) { 157 disable_irq(irq); 158 free_irq(irq, &pca_isa_ops); 159 } 160 release_region(base, IO_SIZE); 161 162 return 0; 163 } 164 165 static struct isa_driver pca_isa_driver = { 166 .probe = pca_isa_probe, 167 .remove = __devexit_p(pca_isa_remove), 168 .driver = { 169 .owner = THIS_MODULE, 170 .name = DRIVER, 171 } 172 }; 173 174 static int __init pca_isa_init(void) 175 { 176 return isa_register_driver(&pca_isa_driver, 1); 177 } 178 179 static void __exit pca_isa_exit(void) 180 { 181 isa_unregister_driver(&pca_isa_driver); 182 } 183 184 MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>"); 185 MODULE_DESCRIPTION("ISA base PCA9564 driver"); 186 MODULE_LICENSE("GPL"); 187 188 module_param(base, ulong, 0); 189 MODULE_PARM_DESC(base, "I/O base address"); 190 191 module_param(irq, int, 0); 192 MODULE_PARM_DESC(irq, "IRQ"); 193 module_param(clock, int, 0); 194 MODULE_PARM_DESC(clock, "Clock rate as described in table 1 of PCA9564 datasheet"); 195 196 module_init(pca_isa_init); 197 module_exit(pca_isa_exit); 198