1 files changed, 175 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-parport-light.c b/drivers/i2c/busses/i2c-parport-light.c
new file mode 100644
index 000000000000..cb5e722301d8
--- /dev/null
+++ b/drivers/i2c/busses/i2c-parport-light.c
@@ -0,0 +1,175 @@
+/* ------------------------------------------------------------------------ *
+ * i2c-parport.c I2C bus over parallel port                                 *
+ * ------------------------------------------------------------------------ *
+   Copyright (C) 2003-2004 Jean Delvare <khali@linux-fr.org>
+   
+   Based on older i2c-velleman.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/ioport.h>
+#include <linux/i2c.h>
+#include <linux/i2c-algo-bit.h>
+#include <asm/io.h>
+#include "i2c-parport.h"
+
+#define DEFAULT_BASE 0x378
+
+static u16 base;
+module_param(base, ushort, 0);
+MODULE_PARM_DESC(base, "Base I/O address");
+
+/* ----- Low-level parallel port access ----------------------------------- */
+
+static inline void port_write(unsigned char p, unsigned char d)
+{
+        outb(d, base+p);
+}
+
+static inline unsigned char port_read(unsigned char p)
+{
+        return inb(base+p);
+}
+
+/* ----- Unified line operation functions --------------------------------- */
+
+static inline void line_set(int state, const struct lineop *op)
+{
+        u8 oldval = port_read(op->port);
+
+        /* Touch only the bit(s) needed */
+        if ((op->inverted && !state) || (!op->inverted && state))
+                port_write(op->port, oldval | op->val);
+        else
+                port_write(op->port, oldval & ~op->val);
+}
+
+static inline int line_get(const struct lineop *op)
+{
+        u8 oldval = port_read(op->port);
+
+        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(state, &adapter_parm[type].setscl);
+}
+
+static void parport_setsda(void *data, int state)
+{
+        line_set(state, &adapter_parm[type].setsda);
+}
+
+static int parport_getscl(void *data)
+{
+        return line_get(&adapter_parm[type].getscl);
+}
+
+static int parport_getsda(void *data)
+{
+        return line_get(&adapter_parm[type].getsda);
+}
+
+/* Encapsulate the functions above in the correct structure
+   Note that getscl will be set to NULL by the attaching code for adapters
+   that cannot read SCL back */
+static struct i2c_algo_bit_data parport_algo_data = {
+        .setsda         = parport_setsda,
+        .setscl         = parport_setscl,
+        .getsda         = parport_getsda,
+        .getscl         = parport_getscl,
+        .udelay         = 50,
+        .mdelay         = 50,
+        .timeout        = HZ,
+}; 
+
+/* ----- I2c structure ---------------------------------------------------- */
+
+static struct i2c_adapter parport_adapter = {
+        .owner          = THIS_MODULE,
+        .class          = I2C_CLASS_HWMON,
+        .id             = I2C_HW_B_LP,
+        .algo_data      = &parport_algo_data,
+        .name           = "Parallel port adapter (light)",
+};
+
+/* ----- 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;
+        }
+        
+        if (base == 0) {
+                printk(KERN_INFO "i2c-parport: using default base 0x%x\n", DEFAULT_BASE);
+                base = DEFAULT_BASE;
+        }
+
+        if (!request_region(base, 3, "i2c-parport"))
+                return -ENODEV;
+
+        if (!adapter_parm[type].getscl.val)
+                parport_algo_data.getscl = NULL;
+
+        /* Reset hardware to a sane state (SCL and SDA high) */
+        parport_setsda(NULL, 1);
+        parport_setscl(NULL, 1);
+        /* Other init if needed (power on...) */
+        if (adapter_parm[type].init.val)
+                line_set(1, &adapter_parm[type].init);
+
+        if (i2c_bit_add_bus(&parport_adapter) < 0) {
+                printk(KERN_ERR "i2c-parport: Unable to register with I2C\n");
+                release_region(base, 3);
+                return -ENODEV;
+        }
+        
+        return 0;
+}
+
+static void __exit i2c_parport_exit(void)
+{
+        /* Un-init if needed (power off...) */
+        if (adapter_parm[type].init.val)
+                line_set(0, &adapter_parm[type].init);
+
+        i2c_bit_del_bus(&parport_adapter);
+        release_region(base, 3);
+}
+
+MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
+MODULE_DESCRIPTION("I2C bus over parallel port (light)");
+MODULE_LICENSE("GPL");
+
+module_init(i2c_parport_init);
+module_exit(i2c_parport_exit);