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-rw-r--r--drivers/i2c/busses/i2c-parport.c268
1 files changed, 268 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-parport.c b/drivers/i2c/busses/i2c-parport.c
new file mode 100644
index 0000000..a257cd5
--- /dev/null
+++ b/drivers/i2c/busses/i2c-parport.c
@@ -0,0 +1,268 @@
+/* ------------------------------------------------------------------------ *
+ * i2c-parport.c I2C bus over parallel port *
+ * ------------------------------------------------------------------------ *
+ Copyright (C) 2003-2007 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/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 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 = 10, /* ~50 kbps */
+ .timeout = HZ,
+};
+
+/* ----- I2c and parallel port call-back functions and structures --------- */
+
+static void i2c_parport_attach (struct parport *port)
+{
+ struct i2c_par *adapter;
+
+ adapter = kzalloc(sizeof(struct i2c_par), GFP_KERNEL);
+ if (adapter == NULL) {
+ printk(KERN_ERR "i2c-parport: Failed to kzalloc\n");
+ return;
+ }
+
+ 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.owner = THIS_MODULE;
+ adapter->adapter.class = I2C_CLASS_HWMON;
+ adapter->adapter.id = I2C_HW_B_LP;
+ strlcpy(adapter->adapter.name, "Parallel port adapter",
+ sizeof(adapter->adapter.name));
+ adapter->algo_data = parport_algo_data;
+ /* Slow down if we can't sense SCL */
+ if (!adapter_parm[type].getscl.val) {
+ adapter->algo_data.getscl = NULL;
+ adapter->algo_data.udelay = 50; /* ~10 kbps */
+ }
+ adapter->algo_data.data = port;
+ adapter->adapter.algo_data = &adapter->algo_data;
+ adapter->adapter.dev.parent = port->physport->dev;
+
+ 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);
+
+ 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_release(adapter->pdev);
+ 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) {
+ i2c_del_adapter(&adapter->adapter);
+
+ /* Un-init if needed (power off...) */
+ if (adapter_parm[type].init.val)
+ line_set(port, 0, &adapter_parm[type].init);
+
+ parport_release(adapter->pdev);
+ parport_unregister_device(adapter->pdev);
+ if (prev)
+ prev->next = adapter->next;
+ else
+ adapter_list = adapter->next;
+ kfree(adapter);
+ return;
+ }
+ }
+}
+
+static struct parport_driver i2c_parport_driver = {
+ .name = "i2c-parport",
+ .attach = i2c_parport_attach,
+ .detach = i2c_parport_detach,
+};
+
+/* ----- Module loading, unloading and information ------------------------ */
+
+static int __init i2c_parport_init(void)
+{
+ if (type < 0) {
+ printk(KERN_WARNING "i2c-parport: adapter type unspecified\n");
+ return -ENODEV;
+ }
+
+ if (type >= ARRAY_SIZE(adapter_parm)) {
+ printk(KERN_WARNING "i2c-parport: invalid type (%d)\n", type);
+ return -ENODEV;
+ }
+
+ return parport_register_driver(&i2c_parport_driver);
+}
+
+static void __exit i2c_parport_exit(void)
+{
+ parport_unregister_driver(&i2c_parport_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);
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