231 lines
6.0 KiB
C
231 lines
6.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* I2C driver for stand-alone PCF8584 style adapters on Zorro cards
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*
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* Original ICY documentation can be found on Aminet:
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* https://aminet.net/package/docs/hard/icy
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*
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* There has been a modern community re-print of this design in 2019:
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* https://www.a1k.org/forum/index.php?threads/70106/
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*
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* The card is basically a Philips PCF8584 connected straight to the
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* beginning of the AutoConfig'd address space (register S1 on base+2),
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* with /INT on /INT2 on the Zorro bus.
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*
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* Copyright (c) 2019 Max Staudt <max@enpas.org>
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*
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* This started as a fork of i2c-elektor.c and has evolved since.
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* Thanks go to its authors for providing a base to grow on.
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*
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*
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* IRQ support is currently not implemented.
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*
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* As it turns out, i2c-algo-pcf is really written with i2c-elektor's
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* edge-triggered ISA interrupts in mind, while the Amiga's Zorro bus has
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* level-triggered interrupts. This means that once an interrupt occurs, we
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* have to tell the PCF8584 to shut up immediately, or it will keep the
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* interrupt line busy and cause an IRQ storm.
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* However, because of the PCF8584's host-side protocol, there is no good
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* way to just quieten it without side effects. Rather, we have to perform
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* the next read/write operation straight away, which will reset the /INT
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* pin. This entails re-designing the core of i2c-algo-pcf in the future.
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* For now, we never request an IRQ from the PCF8584, and poll it instead.
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*/
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/ioport.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/i2c-algo-pcf.h>
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#include <asm/amigaints.h>
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#include <linux/zorro.h>
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#include "../algos/i2c-algo-pcf.h"
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struct icy_i2c {
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struct i2c_adapter adapter;
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void __iomem *reg_s0;
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void __iomem *reg_s1;
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struct fwnode_handle *ltc2990_fwnode;
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struct i2c_client *ltc2990_client;
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};
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/*
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* Functions called by i2c-algo-pcf
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*/
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static void icy_pcf_setpcf(void *data, int ctl, int val)
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{
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struct icy_i2c *i2c = (struct icy_i2c *)data;
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u8 __iomem *address = ctl ? i2c->reg_s1 : i2c->reg_s0;
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z_writeb(val, address);
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}
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static int icy_pcf_getpcf(void *data, int ctl)
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{
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struct icy_i2c *i2c = (struct icy_i2c *)data;
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u8 __iomem *address = ctl ? i2c->reg_s1 : i2c->reg_s0;
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return z_readb(address);
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}
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static int icy_pcf_getown(void *data)
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{
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return 0x55;
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}
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static int icy_pcf_getclock(void *data)
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{
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return 0x1c;
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}
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static void icy_pcf_waitforpin(void *data)
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{
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usleep_range(50, 150);
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}
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/*
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* Main i2c-icy part
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*/
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static unsigned short const icy_ltc2990_addresses[] = {
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0x4c, 0x4d, 0x4e, 0x4f, I2C_CLIENT_END
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};
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/*
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* Additional sensors exposed once this property is applied:
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*
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* in1 will be the voltage of the 5V rail, divided by 2.
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* in2 will be the voltage of the 12V rail, divided by 4.
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* temp3 will be measured using a PCB loop next the chip.
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*/
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static const u32 icy_ltc2990_meas_mode[] = {0, 3};
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static const struct property_entry icy_ltc2990_props[] = {
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PROPERTY_ENTRY_U32_ARRAY("lltc,meas-mode", icy_ltc2990_meas_mode),
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{ }
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};
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static int icy_probe(struct zorro_dev *z,
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const struct zorro_device_id *ent)
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{
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struct icy_i2c *i2c;
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struct i2c_algo_pcf_data *algo_data;
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struct fwnode_handle *new_fwnode;
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struct i2c_board_info ltc2990_info = {
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.type = "ltc2990",
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.addr = 0x4c,
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};
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i2c = devm_kzalloc(&z->dev, sizeof(*i2c), GFP_KERNEL);
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if (!i2c)
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return -ENOMEM;
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algo_data = devm_kzalloc(&z->dev, sizeof(*algo_data), GFP_KERNEL);
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if (!algo_data)
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return -ENOMEM;
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dev_set_drvdata(&z->dev, i2c);
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i2c->adapter.dev.parent = &z->dev;
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i2c->adapter.owner = THIS_MODULE;
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/* i2c->adapter.algo assigned by i2c_pcf_add_bus() */
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i2c->adapter.algo_data = algo_data;
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strlcpy(i2c->adapter.name, "ICY I2C Zorro adapter",
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sizeof(i2c->adapter.name));
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if (!devm_request_mem_region(&z->dev,
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z->resource.start,
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4, i2c->adapter.name))
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return -ENXIO;
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/* Driver private data */
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i2c->reg_s0 = ZTWO_VADDR(z->resource.start);
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i2c->reg_s1 = ZTWO_VADDR(z->resource.start + 2);
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algo_data->data = i2c;
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algo_data->setpcf = icy_pcf_setpcf;
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algo_data->getpcf = icy_pcf_getpcf;
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algo_data->getown = icy_pcf_getown;
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algo_data->getclock = icy_pcf_getclock;
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algo_data->waitforpin = icy_pcf_waitforpin;
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if (i2c_pcf_add_bus(&i2c->adapter)) {
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dev_err(&z->dev, "i2c_pcf_add_bus() failed\n");
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return -ENXIO;
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}
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dev_info(&z->dev, "ICY I2C controller at %pa, IRQ not implemented\n",
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&z->resource.start);
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/*
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* The 2019 a1k.org PCBs have an LTC2990 at 0x4c, so start
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* it automatically once ltc2990 is modprobed.
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*
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* in0 is the voltage of the internal 5V power supply.
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* temp1 is the temperature inside the chip.
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*
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* See property_entry above for in1, in2, temp3.
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*/
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new_fwnode = fwnode_create_software_node(icy_ltc2990_props, NULL);
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if (IS_ERR(new_fwnode)) {
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dev_info(&z->dev, "Failed to create fwnode for LTC2990, error: %ld\n",
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PTR_ERR(new_fwnode));
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} else {
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/*
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* Store the fwnode so we can destroy it on .remove().
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* Only store it on success, as fwnode_remove_software_node()
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* is NULL safe, but not PTR_ERR safe.
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*/
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i2c->ltc2990_fwnode = new_fwnode;
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ltc2990_info.fwnode = new_fwnode;
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i2c->ltc2990_client =
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i2c_new_probed_device(&i2c->adapter,
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<c2990_info,
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icy_ltc2990_addresses,
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NULL);
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}
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return 0;
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}
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static void icy_remove(struct zorro_dev *z)
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{
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struct icy_i2c *i2c = dev_get_drvdata(&z->dev);
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i2c_unregister_device(i2c->ltc2990_client);
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fwnode_remove_software_node(i2c->ltc2990_fwnode);
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i2c_del_adapter(&i2c->adapter);
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}
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static const struct zorro_device_id icy_zorro_tbl[] = {
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{ ZORRO_ID(VMC, 15, 0), },
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{ 0 }
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};
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MODULE_DEVICE_TABLE(zorro, icy_zorro_tbl);
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static struct zorro_driver icy_driver = {
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.name = "i2c-icy",
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.id_table = icy_zorro_tbl,
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.probe = icy_probe,
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.remove = icy_remove,
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};
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module_driver(icy_driver,
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zorro_register_driver,
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zorro_unregister_driver);
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MODULE_AUTHOR("Max Staudt <max@enpas.org>");
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MODULE_DESCRIPTION("I2C bus via PCF8584 on ICY Zorro card");
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MODULE_LICENSE("GPL v2");
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