Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | ------------------------------------------------------------------------- |
| 3 | i2c-adap-ite.c i2c-hw access for the IIC peripheral on the ITE MIPS system |
| 4 | ------------------------------------------------------------------------- |
| 5 | Hai-Pao Fan, MontaVista Software, Inc. |
| 6 | hpfan@mvista.com or source@mvista.com |
| 7 | |
| 8 | Copyright 2001 MontaVista Software Inc. |
| 9 | |
| 10 | ---------------------------------------------------------------------------- |
| 11 | This file was highly leveraged from i2c-elektor.c, which was created |
| 12 | by Simon G. Vogl and Hans Berglund: |
| 13 | |
| 14 | |
| 15 | Copyright (C) 1995-97 Simon G. Vogl |
| 16 | 1998-99 Hans Berglund |
| 17 | |
| 18 | This program is free software; you can redistribute it and/or modify |
| 19 | it under the terms of the GNU General Public License as published by |
| 20 | the Free Software Foundation; either version 2 of the License, or |
| 21 | (at your option) any later version. |
| 22 | |
| 23 | This program is distributed in the hope that it will be useful, |
| 24 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 25 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 26 | GNU General Public License for more details. |
| 27 | |
| 28 | You should have received a copy of the GNU General Public License |
| 29 | along with this program; if not, write to the Free Software |
| 30 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ |
| 31 | /* ------------------------------------------------------------------------- */ |
| 32 | |
| 33 | /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and even |
| 34 | Frodo Looijaard <frodol@dds.nl> */ |
| 35 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | #include <linux/kernel.h> |
| 37 | #include <linux/ioport.h> |
| 38 | #include <linux/module.h> |
| 39 | #include <linux/delay.h> |
| 40 | #include <linux/slab.h> |
| 41 | #include <linux/init.h> |
| 42 | #include <linux/wait.h> |
| 43 | #include <asm/irq.h> |
| 44 | #include <asm/io.h> |
| 45 | |
| 46 | #include <linux/i2c.h> |
| 47 | #include <linux/i2c-algo-ite.h> |
| 48 | #include <linux/i2c-adap-ite.h> |
| 49 | #include "../i2c-ite.h" |
| 50 | |
| 51 | #define DEFAULT_BASE 0x14014030 |
| 52 | #define ITE_IIC_IO_SIZE 0x40 |
| 53 | #define DEFAULT_IRQ 0 |
| 54 | #define DEFAULT_CLOCK 0x1b0e /* default 16MHz/(27+14) = 400KHz */ |
| 55 | #define DEFAULT_OWN 0x55 |
| 56 | |
| 57 | static int base; |
| 58 | static int irq; |
| 59 | static int clock; |
| 60 | static int own; |
| 61 | |
| 62 | static struct iic_ite gpi; |
| 63 | static wait_queue_head_t iic_wait; |
| 64 | static int iic_pending; |
| 65 | static spinlock_t lock; |
| 66 | |
| 67 | /* ----- local functions ---------------------------------------------- */ |
| 68 | |
| 69 | static void iic_ite_setiic(void *data, int ctl, short val) |
| 70 | { |
| 71 | unsigned long j = jiffies + 10; |
| 72 | |
| 73 | pr_debug(" Write 0x%02x to 0x%x\n",(unsigned short)val, ctl&0xff); |
| 74 | #ifdef DEBUG |
| 75 | while (time_before(jiffies, j)) |
| 76 | schedule(); |
| 77 | #endif |
| 78 | outw(val,ctl); |
| 79 | } |
| 80 | |
| 81 | static short iic_ite_getiic(void *data, int ctl) |
| 82 | { |
| 83 | short val; |
| 84 | |
| 85 | val = inw(ctl); |
| 86 | pr_debug("Read 0x%02x from 0x%x\n",(unsigned short)val, ctl&0xff); |
| 87 | return (val); |
| 88 | } |
| 89 | |
| 90 | /* Return our slave address. This is the address |
| 91 | * put on the I2C bus when another master on the bus wants to address us |
| 92 | * as a slave |
| 93 | */ |
| 94 | static int iic_ite_getown(void *data) |
| 95 | { |
| 96 | return (gpi.iic_own); |
| 97 | } |
| 98 | |
| 99 | |
| 100 | static int iic_ite_getclock(void *data) |
| 101 | { |
| 102 | return (gpi.iic_clock); |
| 103 | } |
| 104 | |
| 105 | |
| 106 | /* Put this process to sleep. We will wake up when the |
| 107 | * IIC controller interrupts. |
| 108 | */ |
| 109 | static void iic_ite_waitforpin(void) { |
| 110 | DEFINE_WAIT(wait); |
| 111 | int timeout = 2; |
| 112 | long flags; |
| 113 | |
| 114 | /* If interrupts are enabled (which they are), then put the process to |
| 115 | * sleep. This process will be awakened by two events -- either the |
| 116 | * the IIC peripheral interrupts or the timeout expires. |
| 117 | * If interrupts are not enabled then delay for a reasonable amount |
| 118 | * of time and return. |
| 119 | */ |
| 120 | if (gpi.iic_irq > 0) { |
| 121 | spin_lock_irqsave(&lock, flags); |
| 122 | if (iic_pending == 0) { |
| 123 | spin_unlock_irqrestore(&lock, flags); |
| 124 | prepare_to_wait(&iic_wait, &wait, TASK_INTERRUPTIBLE); |
| 125 | if (schedule_timeout(timeout*HZ)) { |
| 126 | spin_lock_irqsave(&lock, flags); |
| 127 | if (iic_pending == 1) { |
| 128 | iic_pending = 0; |
| 129 | } |
| 130 | spin_unlock_irqrestore(&lock, flags); |
| 131 | } |
| 132 | finish_wait(&iic_wait, &wait); |
| 133 | } else { |
| 134 | iic_pending = 0; |
| 135 | spin_unlock_irqrestore(&lock, flags); |
| 136 | } |
| 137 | } else { |
| 138 | udelay(100); |
| 139 | } |
| 140 | } |
| 141 | |
| 142 | |
| 143 | static irqreturn_t iic_ite_handler(int this_irq, void *dev_id, |
| 144 | struct pt_regs *regs) |
| 145 | { |
| 146 | spin_lock(&lock); |
| 147 | iic_pending = 1; |
| 148 | spin_unlock(&lock); |
| 149 | |
| 150 | wake_up_interruptible(&iic_wait); |
| 151 | |
| 152 | return IRQ_HANDLED; |
| 153 | } |
| 154 | |
| 155 | |
| 156 | /* Lock the region of memory where I/O registers exist. Request our |
| 157 | * interrupt line and register its associated handler. |
| 158 | */ |
| 159 | static int iic_hw_resrc_init(void) |
| 160 | { |
| 161 | if (!request_region(gpi.iic_base, ITE_IIC_IO_SIZE, "i2c")) |
| 162 | return -ENODEV; |
| 163 | |
| 164 | if (gpi.iic_irq <= 0) |
| 165 | return 0; |
| 166 | |
| 167 | if (request_irq(gpi.iic_irq, iic_ite_handler, 0, "ITE IIC", 0) < 0) |
| 168 | gpi.iic_irq = 0; |
| 169 | else |
| 170 | enable_irq(gpi.iic_irq); |
| 171 | |
| 172 | return 0; |
| 173 | } |
| 174 | |
| 175 | |
| 176 | static void iic_ite_release(void) |
| 177 | { |
| 178 | if (gpi.iic_irq > 0) { |
| 179 | disable_irq(gpi.iic_irq); |
| 180 | free_irq(gpi.iic_irq, 0); |
| 181 | } |
| 182 | release_region(gpi.iic_base , 2); |
| 183 | } |
| 184 | |
| 185 | /* ------------------------------------------------------------------------ |
| 186 | * Encapsulate the above functions in the correct operations structure. |
| 187 | * This is only done when more than one hardware adapter is supported. |
| 188 | */ |
| 189 | static struct i2c_algo_iic_data iic_ite_data = { |
| 190 | NULL, |
| 191 | iic_ite_setiic, |
| 192 | iic_ite_getiic, |
| 193 | iic_ite_getown, |
| 194 | iic_ite_getclock, |
| 195 | iic_ite_waitforpin, |
| 196 | 80, 80, 100, /* waits, timeout */ |
| 197 | }; |
| 198 | |
| 199 | static struct i2c_adapter iic_ite_ops = { |
| 200 | .owner = THIS_MODULE, |
| 201 | .id = I2C_HW_I_IIC, |
| 202 | .algo_data = &iic_ite_data, |
| 203 | .dev = { |
| 204 | .name = "ITE IIC adapter", |
| 205 | }, |
| 206 | }; |
| 207 | |
| 208 | /* Called when the module is loaded. This function starts the |
| 209 | * cascade of calls up through the hierarchy of i2c modules (i.e. up to the |
| 210 | * algorithm layer and into to the core layer) |
| 211 | */ |
| 212 | static int __init iic_ite_init(void) |
| 213 | { |
| 214 | |
| 215 | struct iic_ite *piic = &gpi; |
| 216 | |
| 217 | printk(KERN_INFO "Initialize ITE IIC adapter module\n"); |
| 218 | if (base == 0) |
| 219 | piic->iic_base = DEFAULT_BASE; |
| 220 | else |
| 221 | piic->iic_base = base; |
| 222 | |
| 223 | if (irq == 0) |
| 224 | piic->iic_irq = DEFAULT_IRQ; |
| 225 | else |
| 226 | piic->iic_irq = irq; |
| 227 | |
| 228 | if (clock == 0) |
| 229 | piic->iic_clock = DEFAULT_CLOCK; |
| 230 | else |
| 231 | piic->iic_clock = clock; |
| 232 | |
| 233 | if (own == 0) |
| 234 | piic->iic_own = DEFAULT_OWN; |
| 235 | else |
| 236 | piic->iic_own = own; |
| 237 | |
| 238 | iic_ite_data.data = (void *)piic; |
| 239 | init_waitqueue_head(&iic_wait); |
| 240 | spin_lock_init(&lock); |
| 241 | if (iic_hw_resrc_init() == 0) { |
| 242 | if (i2c_iic_add_bus(&iic_ite_ops) < 0) |
| 243 | return -ENODEV; |
| 244 | } else { |
| 245 | return -ENODEV; |
| 246 | } |
| 247 | printk(KERN_INFO " found device at %#x irq %d.\n", |
| 248 | piic->iic_base, piic->iic_irq); |
| 249 | return 0; |
| 250 | } |
| 251 | |
| 252 | |
| 253 | static void iic_ite_exit(void) |
| 254 | { |
| 255 | i2c_iic_del_bus(&iic_ite_ops); |
| 256 | iic_ite_release(); |
| 257 | } |
| 258 | |
| 259 | /* If modules is NOT defined when this file is compiled, then the MODULE_* |
| 260 | * macros will resolve to nothing |
| 261 | */ |
| 262 | MODULE_AUTHOR("MontaVista Software <www.mvista.com>"); |
| 263 | MODULE_DESCRIPTION("I2C-Bus adapter routines for ITE IIC bus adapter"); |
| 264 | MODULE_LICENSE("GPL"); |
| 265 | |
| 266 | module_param(base, int, 0); |
| 267 | module_param(irq, int, 0); |
| 268 | module_param(clock, int, 0); |
| 269 | module_param(own, int, 0); |
| 270 | |
| 271 | |
| 272 | /* Called when module is loaded or when kernel is initialized. |
| 273 | * If MODULES is defined when this file is compiled, then this function will |
| 274 | * resolve to init_module (the function called when insmod is invoked for a |
| 275 | * module). Otherwise, this function is called early in the boot, when the |
| 276 | * kernel is intialized. Check out /include/init.h to see how this works. |
| 277 | */ |
| 278 | module_init(iic_ite_init); |
| 279 | |
| 280 | /* Resolves to module_cleanup when MODULES is defined. */ |
| 281 | module_exit(iic_ite_exit); |