| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* ------------------------------------------------------------------------ * |
| * 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> |
| |
| * ------------------------------------------------------------------------ */ |
| |
| #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_hw(base, ushort, ioport, 0); |
| MODULE_PARM_DESC(base, "Base I/O address"); |
| |
| static int irq; |
| module_param_hw(irq, int, irq, 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 = { |
| }; |
| 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); |