i2c-pca-isa.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 *  i2c-pca-isa.c driver for PCA9564 on ISA boards
  4 *    Copyright (C) 2004 Arcom Control Systems
  5 *    Copyright (C) 2008 Pengutronix
  6 */
  7
  8#include <linux/kernel.h>
  9#include <linux/ioport.h>
 10#include <linux/module.h>
 11#include <linux/moduleparam.h>
 12#include <linux/delay.h>
 13#include <linux/jiffies.h>
 14#include <linux/init.h>
 15#include <linux/interrupt.h>
 16#include <linux/wait.h>
 17#include <linux/isa.h>
 18#include <linux/i2c.h>
 19#include <linux/i2c-algo-pca.h>
 20#include <linux/io.h>
 21
 22#include <asm/irq.h>
 23
 24#define DRIVER "i2c-pca-isa"
 25#define IO_SIZE 4
 26
 27static unsigned long base;
 28static int irq = -1;
 29
 30/* Data sheet recommends 59kHz for 100kHz operation due to variation
 31 * in the actual clock rate */
 32static int clock  = 59000;
 33
 34static struct i2c_adapter pca_isa_ops;
 35static wait_queue_head_t pca_wait;
 36
 37static void pca_isa_writebyte(void *pd, int reg, int val)
 38{
 39#ifdef DEBUG_IO
 40	static char *names[] = { "T/O", "DAT", "ADR", "CON" };
 41	printk(KERN_DEBUG "*** write %s at %#lx <= %#04x\n", names[reg],
 42	       base+reg, val);
 43#endif
 44	outb(val, base+reg);
 45}
 46
 47static int pca_isa_readbyte(void *pd, int reg)
 48{
 49	int res = inb(base+reg);
 50#ifdef DEBUG_IO
 51	{
 52		static char *names[] = { "STA", "DAT", "ADR", "CON" };
 53		printk(KERN_DEBUG "*** read  %s => %#04x\n", names[reg], res);
 54	}
 55#endif
 56	return res;
 57}
 58
 59static int pca_isa_waitforcompletion(void *pd)
 60{
 61	unsigned long timeout;
 62	long ret;
 63
 64	if (irq > -1) {
 65		ret = wait_event_timeout(pca_wait,
 66				pca_isa_readbyte(pd, I2C_PCA_CON)
 67				& I2C_PCA_CON_SI, pca_isa_ops.timeout);
 68	} else {
 69		/* Do polling */
 70		timeout = jiffies + pca_isa_ops.timeout;
 71		do {
 72			ret = time_before(jiffies, timeout);
 73			if (pca_isa_readbyte(pd, I2C_PCA_CON)
 74					& I2C_PCA_CON_SI)
 75				break;
 76			udelay(100);
 77		} while (ret);
 78	}
 79
 80	return ret > 0;
 81}
 82
 83static void pca_isa_resetchip(void *pd)
 84{
 85	/* apparently only an external reset will do it. not a lot can be done */
 86	printk(KERN_WARNING DRIVER ": Haven't figured out how to do a reset yet\n");
 87}
 88
 89static irqreturn_t pca_handler(int this_irq, void *dev_id) {
 90	wake_up(&pca_wait);
 91	return IRQ_HANDLED;
 92}
 93
 94static struct i2c_algo_pca_data pca_isa_data = {
 95	/* .data intentionally left NULL, not needed with ISA */
 96	.write_byte		= pca_isa_writebyte,
 97	.read_byte		= pca_isa_readbyte,
 98	.wait_for_completion_cb	= pca_isa_waitforcompletion,
 99	.reset_chip		= pca_isa_resetchip,
100};
101
102static struct i2c_adapter pca_isa_ops = {
103	.owner          = THIS_MODULE,
104	.algo_data	= &pca_isa_data,
105	.name		= "PCA9564/PCA9665 ISA Adapter",
106	.timeout	= HZ,
107};
108
109static int pca_isa_match(struct device *dev, unsigned int id)
110{
111	int match = base != 0;
112
113	if (match) {
114		if (irq <= -1)
115			dev_warn(dev, "Using polling mode (specify irq)\n");
116	} else
117		dev_err(dev, "Please specify I/O base\n");
118
119	return match;
120}
121
122static int pca_isa_probe(struct device *dev, unsigned int id)
123{
124	init_waitqueue_head(&pca_wait);
125
126	dev_info(dev, "i/o base %#08lx. irq %d\n", base, irq);
127
128#ifdef CONFIG_PPC
129	if (check_legacy_ioport(base)) {
130		dev_err(dev, "I/O address %#08lx is not available\n", base);
131		goto out;
132	}
133#endif
134
135	if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
136		dev_err(dev, "I/O address %#08lx is in use\n", base);
137		goto out;
138	}
139
140	if (irq > -1) {
141		if (request_irq(irq, pca_handler, 0, "i2c-pca-isa", &pca_isa_ops) < 0) {
142			dev_err(dev, "Request irq%d failed\n", irq);
143			goto out_region;
144		}
145	}
146
147	pca_isa_data.i2c_clock = clock;
148	if (i2c_pca_add_bus(&pca_isa_ops) < 0) {
149		dev_err(dev, "Failed to add i2c bus\n");
150		goto out_irq;
151	}
152
153	return 0;
154
155 out_irq:
156	if (irq > -1)
157		free_irq(irq, &pca_isa_ops);
158 out_region:
159	release_region(base, IO_SIZE);
160 out:
161	return -ENODEV;
162}
163
164static void pca_isa_remove(struct device *dev, unsigned int id)
165{
166	i2c_del_adapter(&pca_isa_ops);
167
168	if (irq > -1) {
169		disable_irq(irq);
170		free_irq(irq, &pca_isa_ops);
171	}
172	release_region(base, IO_SIZE);
173}
174
175static struct isa_driver pca_isa_driver = {
176	.match		= pca_isa_match,
177	.probe		= pca_isa_probe,
178	.remove		= pca_isa_remove,
179	.driver = {
180		.owner	= THIS_MODULE,
181		.name	= DRIVER,
182	}
183};
184
185MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
186MODULE_DESCRIPTION("ISA base PCA9564/PCA9665 driver");
187MODULE_LICENSE("GPL");
188
189module_param_hw(base, ulong, ioport, 0);
190MODULE_PARM_DESC(base, "I/O base address");
191module_param_hw(irq, int, irq, 0);
192MODULE_PARM_DESC(irq, "IRQ");
193module_param(clock, int, 0);
194MODULE_PARM_DESC(clock, "Clock rate in hertz.\n\t\t"
195		"For PCA9564: 330000,288000,217000,146000,"
196		"88000,59000,44000,36000\n"
197		"\t\tFor PCA9665:\tStandard: 60300 - 100099\n"
198		"\t\t\t\tFast: 100100 - 400099\n"
199		"\t\t\t\tFast+: 400100 - 10000099\n"
200		"\t\t\t\tTurbo: Up to 1265800");
201module_isa_driver(pca_isa_driver, 1);