Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* ------------------------------------------------------------------------ * |
| 2 | * i2c-parport.c I2C bus over parallel port * |
| 3 | * ------------------------------------------------------------------------ * |
Jean Delvare | 3af07bd | 2007-05-01 23:26:30 +0200 | [diff] [blame] | 4 | Copyright (C) 2003-2007 Jean Delvare <khali@linux-fr.org> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5 | |
| 6 | Based on older i2c-philips-par.c driver |
| 7 | Copyright (C) 1995-2000 Simon G. Vogl |
| 8 | With some changes from: |
| 9 | Frodo Looijaard <frodol@dds.nl> |
| 10 | Kyösti Mälkki <kmalkki@cc.hut.fi> |
| 11 | |
| 12 | This program is free software; you can redistribute it and/or modify |
| 13 | it under the terms of the GNU General Public License as published by |
| 14 | the Free Software Foundation; either version 2 of the License, or |
| 15 | (at your option) any later version. |
| 16 | |
| 17 | This program is distributed in the hope that it will be useful, |
| 18 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | GNU General Public License for more details. |
| 21 | |
| 22 | You should have received a copy of the GNU General Public License |
| 23 | along with this program; if not, write to the Free Software |
| 24 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 25 | * ------------------------------------------------------------------------ */ |
| 26 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | #include <linux/kernel.h> |
| 28 | #include <linux/module.h> |
| 29 | #include <linux/init.h> |
| 30 | #include <linux/parport.h> |
| 31 | #include <linux/i2c.h> |
| 32 | #include <linux/i2c-algo-bit.h> |
| 33 | #include "i2c-parport.h" |
| 34 | |
| 35 | /* ----- Device list ------------------------------------------------------ */ |
| 36 | |
| 37 | struct i2c_par { |
| 38 | struct pardevice *pdev; |
| 39 | struct i2c_adapter adapter; |
| 40 | struct i2c_algo_bit_data algo_data; |
| 41 | struct i2c_par *next; |
| 42 | }; |
| 43 | |
| 44 | static struct i2c_par *adapter_list; |
| 45 | |
| 46 | /* ----- Low-level parallel port access ----------------------------------- */ |
| 47 | |
| 48 | static void port_write_data(struct parport *p, unsigned char d) |
| 49 | { |
| 50 | parport_write_data(p, d); |
| 51 | } |
| 52 | |
| 53 | static void port_write_control(struct parport *p, unsigned char d) |
| 54 | { |
| 55 | parport_write_control(p, d); |
| 56 | } |
| 57 | |
| 58 | static unsigned char port_read_data(struct parport *p) |
| 59 | { |
| 60 | return parport_read_data(p); |
| 61 | } |
| 62 | |
| 63 | static unsigned char port_read_status(struct parport *p) |
| 64 | { |
| 65 | return parport_read_status(p); |
| 66 | } |
| 67 | |
| 68 | static unsigned char port_read_control(struct parport *p) |
| 69 | { |
| 70 | return parport_read_control(p); |
| 71 | } |
| 72 | |
| 73 | static void (*port_write[])(struct parport *, unsigned char) = { |
| 74 | port_write_data, |
| 75 | NULL, |
| 76 | port_write_control, |
| 77 | }; |
| 78 | |
| 79 | static unsigned char (*port_read[])(struct parport *) = { |
| 80 | port_read_data, |
| 81 | port_read_status, |
| 82 | port_read_control, |
| 83 | }; |
| 84 | |
| 85 | /* ----- Unified line operation functions --------------------------------- */ |
| 86 | |
| 87 | static inline void line_set(struct parport *data, int state, |
| 88 | const struct lineop *op) |
| 89 | { |
| 90 | u8 oldval = port_read[op->port](data); |
| 91 | |
| 92 | /* Touch only the bit(s) needed */ |
| 93 | if ((op->inverted && !state) || (!op->inverted && state)) |
| 94 | port_write[op->port](data, oldval | op->val); |
| 95 | else |
| 96 | port_write[op->port](data, oldval & ~op->val); |
| 97 | } |
| 98 | |
| 99 | static inline int line_get(struct parport *data, |
| 100 | const struct lineop *op) |
| 101 | { |
| 102 | u8 oldval = port_read[op->port](data); |
| 103 | |
| 104 | return ((op->inverted && (oldval & op->val) != op->val) |
| 105 | || (!op->inverted && (oldval & op->val) == op->val)); |
| 106 | } |
| 107 | |
| 108 | /* ----- I2C algorithm call-back functions and structures ----------------- */ |
| 109 | |
| 110 | static void parport_setscl(void *data, int state) |
| 111 | { |
| 112 | line_set((struct parport *) data, state, &adapter_parm[type].setscl); |
| 113 | } |
| 114 | |
| 115 | static void parport_setsda(void *data, int state) |
| 116 | { |
| 117 | line_set((struct parport *) data, state, &adapter_parm[type].setsda); |
| 118 | } |
| 119 | |
| 120 | static int parport_getscl(void *data) |
| 121 | { |
| 122 | return line_get((struct parport *) data, &adapter_parm[type].getscl); |
| 123 | } |
| 124 | |
| 125 | static int parport_getsda(void *data) |
| 126 | { |
| 127 | return line_get((struct parport *) data, &adapter_parm[type].getsda); |
| 128 | } |
| 129 | |
| 130 | /* Encapsulate the functions above in the correct structure. |
| 131 | Note that this is only a template, from which the real structures are |
| 132 | copied. The attaching code will set getscl to NULL for adapters that |
Tobias Klauser | 614e24b | 2005-05-19 21:39:06 +0200 | [diff] [blame] | 133 | cannot read SCL back, and will also make the data field point to |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 134 | the parallel port structure. */ |
| 135 | static struct i2c_algo_bit_data parport_algo_data = { |
| 136 | .setsda = parport_setsda, |
| 137 | .setscl = parport_setscl, |
| 138 | .getsda = parport_getsda, |
| 139 | .getscl = parport_getscl, |
Jean Delvare | 3af07bd | 2007-05-01 23:26:30 +0200 | [diff] [blame] | 140 | .udelay = 10, /* ~50 kbps */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 141 | .timeout = HZ, |
| 142 | }; |
| 143 | |
| 144 | /* ----- I2c and parallel port call-back functions and structures --------- */ |
| 145 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | static void i2c_parport_attach (struct parport *port) |
| 147 | { |
| 148 | struct i2c_par *adapter; |
| 149 | |
Deepak Saxena | 5263ebb | 2005-10-17 23:09:43 +0200 | [diff] [blame] | 150 | adapter = kzalloc(sizeof(struct i2c_par), GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 151 | if (adapter == NULL) { |
Deepak Saxena | 5263ebb | 2005-10-17 23:09:43 +0200 | [diff] [blame] | 152 | printk(KERN_ERR "i2c-parport: Failed to kzalloc\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 153 | return; |
| 154 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 155 | |
| 156 | pr_debug("i2c-parport: attaching to %s\n", port->name); |
| 157 | adapter->pdev = parport_register_device(port, "i2c-parport", |
| 158 | NULL, NULL, NULL, PARPORT_FLAG_EXCL, NULL); |
| 159 | if (!adapter->pdev) { |
| 160 | printk(KERN_ERR "i2c-parport: Unable to register with parport\n"); |
| 161 | goto ERROR0; |
| 162 | } |
| 163 | |
| 164 | /* Fill the rest of the structure */ |
Jean Delvare | cacf226 | 2007-05-01 23:26:29 +0200 | [diff] [blame] | 165 | adapter->adapter.owner = THIS_MODULE; |
| 166 | adapter->adapter.class = I2C_CLASS_HWMON; |
| 167 | adapter->adapter.id = I2C_HW_B_LP; |
| 168 | strlcpy(adapter->adapter.name, "Parallel port adapter", |
| 169 | sizeof(adapter->adapter.name)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | adapter->algo_data = parport_algo_data; |
Jean Delvare | 3af07bd | 2007-05-01 23:26:30 +0200 | [diff] [blame] | 171 | /* Slow down if we can't sense SCL */ |
| 172 | if (!adapter_parm[type].getscl.val) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 173 | adapter->algo_data.getscl = NULL; |
Jean Delvare | 3af07bd | 2007-05-01 23:26:30 +0200 | [diff] [blame] | 174 | adapter->algo_data.udelay = 50; /* ~10 kbps */ |
| 175 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 176 | adapter->algo_data.data = port; |
| 177 | adapter->adapter.algo_data = &adapter->algo_data; |
David Brownell | da67529 | 2007-05-08 00:27:42 -0700 | [diff] [blame] | 178 | adapter->adapter.dev.parent = port->physport->dev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 | |
| 180 | if (parport_claim_or_block(adapter->pdev) < 0) { |
| 181 | printk(KERN_ERR "i2c-parport: Could not claim parallel port\n"); |
| 182 | goto ERROR1; |
| 183 | } |
| 184 | |
| 185 | /* Reset hardware to a sane state (SCL and SDA high) */ |
| 186 | parport_setsda(port, 1); |
| 187 | parport_setscl(port, 1); |
| 188 | /* Other init if needed (power on...) */ |
| 189 | if (adapter_parm[type].init.val) |
| 190 | line_set(port, 1, &adapter_parm[type].init); |
| 191 | |
| 192 | parport_release(adapter->pdev); |
| 193 | |
| 194 | if (i2c_bit_add_bus(&adapter->adapter) < 0) { |
| 195 | printk(KERN_ERR "i2c-parport: Unable to register with I2C\n"); |
| 196 | goto ERROR1; |
| 197 | } |
| 198 | |
| 199 | /* Add the new adapter to the list */ |
| 200 | adapter->next = adapter_list; |
| 201 | adapter_list = adapter; |
| 202 | return; |
| 203 | |
| 204 | ERROR1: |
| 205 | parport_unregister_device(adapter->pdev); |
| 206 | ERROR0: |
| 207 | kfree(adapter); |
| 208 | } |
| 209 | |
| 210 | static void i2c_parport_detach (struct parport *port) |
| 211 | { |
| 212 | struct i2c_par *adapter, *prev; |
| 213 | |
| 214 | /* Walk the list */ |
| 215 | for (prev = NULL, adapter = adapter_list; adapter; |
| 216 | prev = adapter, adapter = adapter->next) { |
| 217 | if (adapter->pdev->port == port) { |
Jean Delvare | 3af07bd | 2007-05-01 23:26:30 +0200 | [diff] [blame] | 218 | i2c_del_adapter(&adapter->adapter); |
| 219 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 220 | /* Un-init if needed (power off...) */ |
| 221 | if (adapter_parm[type].init.val) |
| 222 | line_set(port, 0, &adapter_parm[type].init); |
| 223 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 224 | parport_unregister_device(adapter->pdev); |
| 225 | if (prev) |
| 226 | prev->next = adapter->next; |
| 227 | else |
| 228 | adapter_list = adapter->next; |
| 229 | kfree(adapter); |
| 230 | return; |
| 231 | } |
| 232 | } |
| 233 | } |
| 234 | |
Jean Delvare | 6c129be | 2005-10-08 00:17:35 +0200 | [diff] [blame] | 235 | static struct parport_driver i2c_parport_driver = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 236 | .name = "i2c-parport", |
| 237 | .attach = i2c_parport_attach, |
| 238 | .detach = i2c_parport_detach, |
| 239 | }; |
| 240 | |
| 241 | /* ----- Module loading, unloading and information ------------------------ */ |
| 242 | |
| 243 | static int __init i2c_parport_init(void) |
| 244 | { |
Mark M. Hoffman | e97b81d | 2006-03-23 16:50:25 +0100 | [diff] [blame] | 245 | if (type < 0) { |
| 246 | printk(KERN_WARNING "i2c-parport: adapter type unspecified\n"); |
| 247 | return -ENODEV; |
| 248 | } |
| 249 | |
| 250 | if (type >= ARRAY_SIZE(adapter_parm)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 251 | printk(KERN_WARNING "i2c-parport: invalid type (%d)\n", type); |
Mark M. Hoffman | e97b81d | 2006-03-23 16:50:25 +0100 | [diff] [blame] | 252 | return -ENODEV; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 253 | } |
Tobias Klauser | 7e3d7db | 2006-01-09 23:19:51 +0100 | [diff] [blame] | 254 | |
Jean Delvare | 6c129be | 2005-10-08 00:17:35 +0200 | [diff] [blame] | 255 | return parport_register_driver(&i2c_parport_driver); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 256 | } |
| 257 | |
| 258 | static void __exit i2c_parport_exit(void) |
| 259 | { |
Jean Delvare | 6c129be | 2005-10-08 00:17:35 +0200 | [diff] [blame] | 260 | parport_unregister_driver(&i2c_parport_driver); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 261 | } |
| 262 | |
| 263 | MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); |
| 264 | MODULE_DESCRIPTION("I2C bus over parallel port"); |
| 265 | MODULE_LICENSE("GPL"); |
| 266 | |
| 267 | module_init(i2c_parport_init); |
| 268 | module_exit(i2c_parport_exit); |