| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* ------------------------------------------------------------------------ * |
| * i2c-parport.c I2C bus over parallel port * |
| * ------------------------------------------------------------------------ * |
| Copyright (C) 2003-2011 Jean Delvare <jdelvare@suse.de> |
| |
| 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> |
| |
| * ------------------------------------------------------------------------ */ |
| |
| #define pr_fmt(fmt) "i2c-parport: " fmt |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/delay.h> |
| #include <linux/parport.h> |
| #include <linux/i2c.h> |
| #include <linux/i2c-algo-bit.h> |
| #include <linux/i2c-smbus.h> |
| #include <linux/slab.h> |
| #include <linux/list.h> |
| #include <linux/mutex.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_smbus_alert_setup alert_data; |
| struct i2c_client *ara; |
| struct list_head node; |
| }; |
| |
| static LIST_HEAD(adapter_list); |
| static DEFINE_MUTEX(adapter_list_lock); |
| #define MAX_DEVICE 4 |
| static int parport[MAX_DEVICE] = {0, -1, -1, -1}; |
| |
| |
| /* ----- 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 (* const port_write[])(struct parport *, unsigned char) = { |
| port_write_data, |
| NULL, |
| port_write_control, |
| }; |
| |
| static unsigned char (* const 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 const 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_irq(void *data) |
| { |
| struct i2c_par *adapter = data; |
| struct i2c_client *ara = adapter->ara; |
| |
| if (ara) { |
| dev_dbg(&ara->dev, "SMBus alert received\n"); |
| i2c_handle_smbus_alert(ara); |
| } else |
| dev_dbg(&adapter->adapter.dev, |
| "SMBus alert received but no ARA client!\n"); |
| } |
| |
| static void i2c_parport_attach(struct parport *port) |
| { |
| struct i2c_par *adapter; |
| int i; |
| struct pardev_cb i2c_parport_cb; |
| |
| for (i = 0; i < MAX_DEVICE; i++) { |
| if (parport[i] == -1) |
| continue; |
| if (port->number == parport[i]) |
| break; |
| } |
| if (i == MAX_DEVICE) { |
| pr_debug("Not using parport%d.\n", port->number); |
| return; |
| } |
| |
| adapter = kzalloc(sizeof(struct i2c_par), GFP_KERNEL); |
| if (!adapter) |
| return; |
| memset(&i2c_parport_cb, 0, sizeof(i2c_parport_cb)); |
| i2c_parport_cb.flags = PARPORT_FLAG_EXCL; |
| i2c_parport_cb.irq_func = i2c_parport_irq; |
| i2c_parport_cb.private = adapter; |
| |
| pr_debug("attaching to %s\n", port->name); |
| parport_disable_irq(port); |
| adapter->pdev = parport_register_dev_model(port, "i2c-parport", |
| &i2c_parport_cb, i); |
| if (!adapter->pdev) { |
| pr_err("Unable to register with parport\n"); |
| goto err_free; |
| } |
| |
| /* Fill the rest of the structure */ |
| adapter->adapter.owner = THIS_MODULE; |
| adapter->adapter.class = I2C_CLASS_HWMON; |
| 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) { |
| dev_err(&adapter->pdev->dev, |
| "Could not claim parallel port\n"); |
| goto err_unregister; |
| } |
| |
| /* 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); |
| /* Give powered devices some time to settle */ |
| msleep(100); |
| } |
| |
| if (i2c_bit_add_bus(&adapter->adapter) < 0) { |
| dev_err(&adapter->pdev->dev, "Unable to register with I2C\n"); |
| goto err_unregister; |
| } |
| |
| /* Setup SMBus alert if supported */ |
| if (adapter_parm[type].smbus_alert) { |
| adapter->ara = i2c_setup_smbus_alert(&adapter->adapter, |
| &adapter->alert_data); |
| if (adapter->ara) |
| parport_enable_irq(port); |
| else |
| dev_warn(&adapter->pdev->dev, |
| "Failed to register ARA client\n"); |
| } |
| |
| /* Add the new adapter to the list */ |
| mutex_lock(&adapter_list_lock); |
| list_add_tail(&adapter->node, &adapter_list); |
| mutex_unlock(&adapter_list_lock); |
| return; |
| |
| err_unregister: |
| parport_release(adapter->pdev); |
| parport_unregister_device(adapter->pdev); |
| err_free: |
| kfree(adapter); |
| } |
| |
| static void i2c_parport_detach(struct parport *port) |
| { |
| struct i2c_par *adapter, *_n; |
| |
| /* Walk the list */ |
| mutex_lock(&adapter_list_lock); |
| list_for_each_entry_safe(adapter, _n, &adapter_list, node) { |
| if (adapter->pdev->port == port) { |
| if (adapter->ara) { |
| parport_disable_irq(port); |
| i2c_unregister_device(adapter->ara); |
| } |
| 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); |
| list_del(&adapter->node); |
| kfree(adapter); |
| } |
| } |
| mutex_unlock(&adapter_list_lock); |
| } |
| |
| static struct parport_driver i2c_parport_driver = { |
| .name = "i2c-parport", |
| .match_port = i2c_parport_attach, |
| .detach = i2c_parport_detach, |
| .devmodel = true, |
| }; |
| |
| /* ----- Module loading, unloading and information ------------------------ */ |
| |
| static int __init i2c_parport_init(void) |
| { |
| if (type < 0) { |
| pr_warn("adapter type unspecified\n"); |
| return -ENODEV; |
| } |
| |
| if (type >= ARRAY_SIZE(adapter_parm)) { |
| pr_warn("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 <jdelvare@suse.de>"); |
| MODULE_DESCRIPTION("I2C bus over parallel port"); |
| MODULE_LICENSE("GPL"); |
| |
| module_param_array(parport, int, NULL, 0); |
| MODULE_PARM_DESC(parport, |
| "List of parallel ports to bind to, by index.\n" |
| " Atmost " __stringify(MAX_DEVICE) " devices are supported.\n" |
| " Default is one device connected to parport0.\n" |
| ); |
| |
| module_init(i2c_parport_init); |
| module_exit(i2c_parport_exit); |