--- /dev/null
+/* ------------------------------------------------------------------------ *
+ * i2c-parport-light.c I2C bus over parallel port *
+ * ------------------------------------------------------------------------ *
+ Copyright (C) 2003-2010 Jean Delvare <jdelvare@suse.de>
+
+ 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.
+ * ------------------------------------------------------------------------ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/ioport.h>
+#include <linux/i2c.h>
+#include <linux/i2c-algo-bit.h>
+#include <linux/i2c-smbus.h>
+#include <linux/io.h>
+#include "i2c-parport.h"
+
+#define DEFAULT_BASE 0x378
+#define DRVNAME "i2c-parport-light"
+
+static struct platform_device *pdev;
+
+static u16 base;
+module_param(base, ushort, 0);
+MODULE_PARM_DESC(base, "Base I/O address");
+
+static int irq;
+module_param(irq, int, 0);
+MODULE_PARM_DESC(irq, "IRQ (optional)");
+
+/* ----- 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,
+ .timeout = HZ,
+};
+
+/* ----- Driver registration ---------------------------------------------- */
+
+static struct i2c_adapter parport_adapter = {
+ .owner = THIS_MODULE,
+ .class = I2C_CLASS_HWMON,
+ .algo_data = &parport_algo_data,
+ .name = "Parallel port adapter (light)",
+};
+
+/* SMBus alert support */
+static struct i2c_smbus_alert_setup alert_data = {
+ .alert_edge_triggered = 1,
+};
+static struct i2c_client *ara;
+static struct lineop parport_ctrl_irq = {
+ .val = (1 << 4),
+ .port = PORT_CTRL,
+};
+
+static int i2c_parport_probe(struct platform_device *pdev)
+{
+ int err;
+
+ /* 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);
+ /* Give powered devices some time to settle */
+ msleep(100);
+ }
+
+ parport_adapter.dev.parent = &pdev->dev;
+ err = i2c_bit_add_bus(&parport_adapter);
+ if (err) {
+ dev_err(&pdev->dev, "Unable to register with I2C\n");
+ return err;
+ }
+
+ /* Setup SMBus alert if supported */
+ if (adapter_parm[type].smbus_alert && irq) {
+ alert_data.irq = irq;
+ ara = i2c_setup_smbus_alert(&parport_adapter, &alert_data);
+ if (ara)
+ line_set(1, &parport_ctrl_irq);
+ else
+ dev_warn(&pdev->dev, "Failed to register ARA client\n");
+ }
+
+ return 0;
+}
+
+static int i2c_parport_remove(struct platform_device *pdev)
+{
+ if (ara) {
+ line_set(0, &parport_ctrl_irq);
+ i2c_unregister_device(ara);
+ ara = NULL;
+ }
+ i2c_del_adapter(&parport_adapter);
+
+ /* Un-init if needed (power off...) */
+ if (adapter_parm[type].init.val)
+ line_set(0, &adapter_parm[type].init);
+
+ return 0;
+}
+
+static struct platform_driver i2c_parport_driver = {
+ .driver = {
+ .name = DRVNAME,
+ },
+ .probe = i2c_parport_probe,
+ .remove = i2c_parport_remove,
+};
+
+static int __init i2c_parport_device_add(u16 address)
+{
+ int err;
+
+ pdev = platform_device_alloc(DRVNAME, -1);
+ if (!pdev) {
+ err = -ENOMEM;
+ printk(KERN_ERR DRVNAME ": Device allocation failed\n");
+ goto exit;
+ }
+
+ err = platform_device_add(pdev);
+ if (err) {
+ printk(KERN_ERR DRVNAME ": Device addition failed (%d)\n",
+ err);
+ goto exit_device_put;
+ }
+
+ return 0;
+
+exit_device_put:
+ platform_device_put(pdev);
+exit:
+ return err;
+}
+
+static int __init i2c_parport_init(void)
+{
+ int err;
+
+ if (type < 0) {
+ printk(KERN_ERR DRVNAME ": adapter type unspecified\n");
+ return -ENODEV;
+ }
+
+ if (type >= ARRAY_SIZE(adapter_parm)) {
+ printk(KERN_ERR DRVNAME ": invalid type (%d)\n", type);
+ return -ENODEV;
+ }
+
+ if (base == 0) {
+ pr_info(DRVNAME ": using default base 0x%x\n", DEFAULT_BASE);
+ base = DEFAULT_BASE;
+ }
+
+ if (!request_region(base, 3, DRVNAME))
+ return -EBUSY;
+
+ if (irq != 0)
+ pr_info(DRVNAME ": using irq %d\n", irq);
+
+ if (!adapter_parm[type].getscl.val)
+ parport_algo_data.getscl = NULL;
+
+ /* Sets global pdev as a side effect */
+ err = i2c_parport_device_add(base);
+ if (err)
+ goto exit_release;
+
+ err = platform_driver_register(&i2c_parport_driver);
+ if (err)
+ goto exit_device;
+
+ return 0;
+
+exit_device:
+ platform_device_unregister(pdev);
+exit_release:
+ release_region(base, 3);
+ return err;
+}
+
+static void __exit i2c_parport_exit(void)
+{
+ platform_driver_unregister(&i2c_parport_driver);
+ platform_device_unregister(pdev);
+ release_region(base, 3);
+}
+
+MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
+MODULE_DESCRIPTION("I2C bus over parallel port (light)");
+MODULE_LICENSE("GPL");
+
+module_init(i2c_parport_init);
+module_exit(i2c_parport_exit);
Code Review / kvmfornfv.git / blobdiff