202 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * i2c-pca-isa.c driver for PCA9564 on ISA boards4 * Copyright (C) 2004 Arcom Control Systems5 * Copyright (C) 2008 Pengutronix6 */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 426 27static unsigned long base;28static int irq = -1;29 30/* Data sheet recommends 59kHz for 100kHz operation due to variation31 * 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_IO40 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#endif44 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_IO51 {52 static char *names[] = { "STA", "DAT", "ADR", "CON" };53 printk(KERN_DEBUG "*** read %s => %#04x\n", names[reg], res);54 }55#endif56 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 = 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 } else117 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_PPC129 if (check_legacy_ioport(base)) {130 dev_err(dev, "I/O address %#08lx is not available\n", base);131 goto out;132 }133#endif134 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);202