diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/i2c/busses/i2c-parport.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'drivers/i2c/busses/i2c-parport.c')
-rw-r--r-- | drivers/i2c/busses/i2c-parport.c | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-parport.c b/drivers/i2c/busses/i2c-parport.c new file mode 100644 index 000000000000..e9560bab51c4 --- /dev/null +++ b/drivers/i2c/busses/i2c-parport.c @@ -0,0 +1,267 @@ +/* ------------------------------------------------------------------------ * + * i2c-parport.c I2C bus over parallel port * + * ------------------------------------------------------------------------ * + Copyright (C) 2003-2004 Jean Delvare <khali@linux-fr.org> + + Based on older i2c-philips-par.c driver + Copyright (C) 1995-2000 Simon G. Vogl + With some changes from: + Frodo Looijaard <frodol@dds.nl> + Kyösti Mälkki <kmalkki@cc.hut.fi> + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + * ------------------------------------------------------------------------ */ + +#include <linux/config.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/parport.h> +#include <linux/i2c.h> +#include <linux/i2c-algo-bit.h> +#include "i2c-parport.h" + +/* ----- Device list ------------------------------------------------------ */ + +struct i2c_par { + struct pardevice *pdev; + struct i2c_adapter adapter; + struct i2c_algo_bit_data algo_data; + struct i2c_par *next; +}; + +static struct i2c_par *adapter_list; + +/* ----- Low-level parallel port access ----------------------------------- */ + +static void port_write_data(struct parport *p, unsigned char d) +{ + parport_write_data(p, d); +} + +static void port_write_control(struct parport *p, unsigned char d) +{ + parport_write_control(p, d); +} + +static unsigned char port_read_data(struct parport *p) +{ + return parport_read_data(p); +} + +static unsigned char port_read_status(struct parport *p) +{ + return parport_read_status(p); +} + +static unsigned char port_read_control(struct parport *p) +{ + return parport_read_control(p); +} + +static void (*port_write[])(struct parport *, unsigned char) = { + port_write_data, + NULL, + port_write_control, +}; + +static unsigned char (*port_read[])(struct parport *) = { + port_read_data, + port_read_status, + port_read_control, +}; + +/* ----- Unified line operation functions --------------------------------- */ + +static inline void line_set(struct parport *data, int state, + const struct lineop *op) +{ + u8 oldval = port_read[op->port](data); + + /* Touch only the bit(s) needed */ + if ((op->inverted && !state) || (!op->inverted && state)) + port_write[op->port](data, oldval | op->val); + else + port_write[op->port](data, oldval & ~op->val); +} + +static inline int line_get(struct parport *data, + const struct lineop *op) +{ + u8 oldval = port_read[op->port](data); + + return ((op->inverted && (oldval & op->val) != op->val) + || (!op->inverted && (oldval & op->val) == op->val)); +} + +/* ----- I2C algorithm call-back functions and structures ----------------- */ + +static void parport_setscl(void *data, int state) +{ + line_set((struct parport *) data, state, &adapter_parm[type].setscl); +} + +static void parport_setsda(void *data, int state) +{ + line_set((struct parport *) data, state, &adapter_parm[type].setsda); +} + +static int parport_getscl(void *data) +{ + return line_get((struct parport *) data, &adapter_parm[type].getscl); +} + +static int parport_getsda(void *data) +{ + return line_get((struct parport *) data, &adapter_parm[type].getsda); +} + +/* Encapsulate the functions above in the correct structure. + Note that this is only a template, from which the real structures are + copied. The attaching code will set getscl to NULL for adapters that + cannot read SCL back, and will also make the the data field point to + the parallel port structure. */ +static struct i2c_algo_bit_data parport_algo_data = { + .setsda = parport_setsda, + .setscl = parport_setscl, + .getsda = parport_getsda, + .getscl = parport_getscl, + .udelay = 60, + .mdelay = 60, + .timeout = HZ, +}; + +/* ----- I2c and parallel port call-back functions and structures --------- */ + +static struct i2c_adapter parport_adapter = { + .owner = THIS_MODULE, + .class = I2C_CLASS_HWMON, + .id = I2C_HW_B_LP, + .name = "Parallel port adapter", +}; + +static void i2c_parport_attach (struct parport *port) +{ + struct i2c_par *adapter; + + adapter = kmalloc(sizeof(struct i2c_par), GFP_KERNEL); + if (adapter == NULL) { + printk(KERN_ERR "i2c-parport: Failed to kmalloc\n"); + return; + } + memset(adapter, 0x00, sizeof(struct i2c_par)); + + pr_debug("i2c-parport: attaching to %s\n", port->name); + adapter->pdev = parport_register_device(port, "i2c-parport", + NULL, NULL, NULL, PARPORT_FLAG_EXCL, NULL); + if (!adapter->pdev) { + printk(KERN_ERR "i2c-parport: Unable to register with parport\n"); + goto ERROR0; + } + + /* Fill the rest of the structure */ + adapter->adapter = parport_adapter; + adapter->algo_data = parport_algo_data; + if (!adapter_parm[type].getscl.val) + adapter->algo_data.getscl = NULL; + adapter->algo_data.data = port; + adapter->adapter.algo_data = &adapter->algo_data; + + if (parport_claim_or_block(adapter->pdev) < 0) { + printk(KERN_ERR "i2c-parport: Could not claim parallel port\n"); + goto ERROR1; + } + + /* Reset hardware to a sane state (SCL and SDA high) */ + parport_setsda(port, 1); + parport_setscl(port, 1); + /* Other init if needed (power on...) */ + if (adapter_parm[type].init.val) + line_set(port, 1, &adapter_parm[type].init); + + parport_release(adapter->pdev); + + if (i2c_bit_add_bus(&adapter->adapter) < 0) { + printk(KERN_ERR "i2c-parport: Unable to register with I2C\n"); + goto ERROR1; + } + + /* Add the new adapter to the list */ + adapter->next = adapter_list; + adapter_list = adapter; + return; + +ERROR1: + parport_unregister_device(adapter->pdev); +ERROR0: + kfree(adapter); +} + +static void i2c_parport_detach (struct parport *port) +{ + struct i2c_par *adapter, *prev; + + /* Walk the list */ + for (prev = NULL, adapter = adapter_list; adapter; + prev = adapter, adapter = adapter->next) { + if (adapter->pdev->port == port) { + /* Un-init if needed (power off...) */ + if (adapter_parm[type].init.val) + line_set(port, 0, &adapter_parm[type].init); + + i2c_bit_del_bus(&adapter->adapter); + parport_unregister_device(adapter->pdev); + if (prev) + prev->next = adapter->next; + else + adapter_list = adapter->next; + kfree(adapter); + return; + } + } +} + +static struct parport_driver i2c_driver = { + .name = "i2c-parport", + .attach = i2c_parport_attach, + .detach = i2c_parport_detach, +}; + +/* ----- Module loading, unloading and information ------------------------ */ + +static int __init i2c_parport_init(void) +{ + int type_count; + + type_count = sizeof(adapter_parm)/sizeof(struct adapter_parm); + if (type < 0 || type >= type_count) { + printk(KERN_WARNING "i2c-parport: invalid type (%d)\n", type); + type = 0; + } + + return parport_register_driver(&i2c_driver); +} + +static void __exit i2c_parport_exit(void) +{ + parport_unregister_driver(&i2c_driver); +} + +MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); +MODULE_DESCRIPTION("I2C bus over parallel port"); +MODULE_LICENSE("GPL"); + +module_init(i2c_parport_init); +module_exit(i2c_parport_exit); |