210 lines
5 KiB
C
210 lines
5 KiB
C
/*
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* i2c-pca-isa.c driver for PCA9564 on ISA boards
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* Copyright (C) 2004 Arcom Control Systems
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* Copyright (C) 2008 Pengutronix
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/kernel.h>
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#include <linux/ioport.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/wait.h>
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#include <linux/isa.h>
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#include <linux/i2c.h>
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#include <linux/i2c-algo-pca.h>
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#include <asm/io.h>
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#include <asm/irq.h>
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#define DRIVER "i2c-pca-isa"
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#define IO_SIZE 4
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static unsigned long base;
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static int irq = -1;
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/* Data sheet recommends 59kHz for 100kHz operation due to variation
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* in the actual clock rate */
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static int clock = I2C_PCA_CON_59kHz;
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static wait_queue_head_t pca_wait;
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static void pca_isa_writebyte(void *pd, int reg, int val)
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{
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#ifdef DEBUG_IO
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static char *names[] = { "T/O", "DAT", "ADR", "CON" };
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printk("*** write %s at %#lx <= %#04x\n", names[reg], base+reg, val);
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#endif
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outb(val, base+reg);
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}
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static int pca_isa_readbyte(void *pd, int reg)
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{
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int res = inb(base+reg);
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#ifdef DEBUG_IO
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{
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static char *names[] = { "STA", "DAT", "ADR", "CON" };
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printk("*** read %s => %#04x\n", names[reg], res);
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}
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#endif
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return res;
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}
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static int pca_isa_waitforcompletion(void *pd)
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{
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int ret = 0;
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if (irq > -1) {
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ret = wait_event_interruptible(pca_wait,
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pca_isa_readbyte(pd, I2C_PCA_CON) & I2C_PCA_CON_SI);
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} else {
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while ((pca_isa_readbyte(pd, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
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udelay(100);
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}
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return ret;
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}
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static void pca_isa_resetchip(void *pd)
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{
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/* apparently only an external reset will do it. not a lot can be done */
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printk(KERN_WARNING DRIVER ": Haven't figured out how to do a reset yet\n");
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}
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static irqreturn_t pca_handler(int this_irq, void *dev_id) {
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wake_up_interruptible(&pca_wait);
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return IRQ_HANDLED;
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}
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static struct i2c_algo_pca_data pca_isa_data = {
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/* .data intentionally left NULL, not needed with ISA */
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.write_byte = pca_isa_writebyte,
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.read_byte = pca_isa_readbyte,
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.wait_for_completion = pca_isa_waitforcompletion,
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.reset_chip = pca_isa_resetchip,
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};
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static struct i2c_adapter pca_isa_ops = {
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.owner = THIS_MODULE,
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.algo_data = &pca_isa_data,
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.name = "PCA9564 ISA Adapter",
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.timeout = 100,
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};
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static int __devinit pca_isa_match(struct device *dev, unsigned int id)
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{
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int match = base != 0;
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if (match) {
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if (irq <= -1)
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dev_warn(dev, "Using polling mode (specify irq)\n");
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} else
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dev_err(dev, "Please specify I/O base\n");
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return match;
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}
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static int __devinit pca_isa_probe(struct device *dev, unsigned int id)
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{
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init_waitqueue_head(&pca_wait);
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dev_info(dev, "i/o base %#08lx. irq %d\n", base, irq);
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#ifdef CONFIG_PPC
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if (check_legacy_ioport(base)) {
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dev_err(dev, "I/O address %#08lx is not available\n", base);
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goto out;
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}
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#endif
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if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
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dev_err(dev, "I/O address %#08lx is in use\n", base);
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goto out;
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}
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if (irq > -1) {
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if (request_irq(irq, pca_handler, 0, "i2c-pca-isa", &pca_isa_ops) < 0) {
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dev_err(dev, "Request irq%d failed\n", irq);
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goto out_region;
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}
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}
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pca_isa_data.i2c_clock = clock;
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if (i2c_pca_add_bus(&pca_isa_ops) < 0) {
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dev_err(dev, "Failed to add i2c bus\n");
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goto out_irq;
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}
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return 0;
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out_irq:
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if (irq > -1)
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free_irq(irq, &pca_isa_ops);
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out_region:
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release_region(base, IO_SIZE);
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out:
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return -ENODEV;
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}
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static int __devexit pca_isa_remove(struct device *dev, unsigned int id)
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{
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i2c_del_adapter(&pca_isa_ops);
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if (irq > -1) {
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disable_irq(irq);
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free_irq(irq, &pca_isa_ops);
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}
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release_region(base, IO_SIZE);
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return 0;
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}
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static struct isa_driver pca_isa_driver = {
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.match = pca_isa_match,
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.probe = pca_isa_probe,
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.remove = __devexit_p(pca_isa_remove),
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.driver = {
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.owner = THIS_MODULE,
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.name = DRIVER,
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}
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};
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static int __init pca_isa_init(void)
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{
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return isa_register_driver(&pca_isa_driver, 1);
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}
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static void __exit pca_isa_exit(void)
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{
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isa_unregister_driver(&pca_isa_driver);
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}
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MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
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MODULE_DESCRIPTION("ISA base PCA9564 driver");
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MODULE_LICENSE("GPL");
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module_param(base, ulong, 0);
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MODULE_PARM_DESC(base, "I/O base address");
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module_param(irq, int, 0);
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MODULE_PARM_DESC(irq, "IRQ");
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module_param(clock, int, 0);
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MODULE_PARM_DESC(clock, "Clock rate as described in table 1 of PCA9564 datasheet");
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module_init(pca_isa_init);
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module_exit(pca_isa_exit);
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