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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2005 Simtec Electronics4 * Ben Dooks <ben@simtec.co.uk>5 *6 * Simtec Generic I2C Controller7*/8 9#include <linux/kernel.h>10#include <linux/module.h>11#include <linux/delay.h>12#include <linux/platform_device.h>13#include <linux/slab.h>14#include <linux/io.h>15 16#include <linux/i2c.h>17#include <linux/i2c-algo-bit.h>18 19struct simtec_i2c_data {20 struct resource *ioarea;21 void __iomem *reg;22 struct i2c_adapter adap;23 struct i2c_algo_bit_data bit;24};25 26#define CMD_SET_SDA (1<<2)27#define CMD_SET_SCL (1<<3)28 29#define STATE_SDA (1<<0)30#define STATE_SCL (1<<1)31 32/* i2c bit-bus functions */33 34static void simtec_i2c_setsda(void *pw, int state)35{36 struct simtec_i2c_data *pd = pw;37 writeb(CMD_SET_SDA | (state ? STATE_SDA : 0), pd->reg);38}39 40static void simtec_i2c_setscl(void *pw, int state)41{42 struct simtec_i2c_data *pd = pw;43 writeb(CMD_SET_SCL | (state ? STATE_SCL : 0), pd->reg);44}45 46static int simtec_i2c_getsda(void *pw)47{48 struct simtec_i2c_data *pd = pw;49 return readb(pd->reg) & STATE_SDA ? 1 : 0;50}51 52static int simtec_i2c_getscl(void *pw)53{54 struct simtec_i2c_data *pd = pw;55 return readb(pd->reg) & STATE_SCL ? 1 : 0;56}57 58/* device registration */59 60static int simtec_i2c_probe(struct platform_device *dev)61{62 struct simtec_i2c_data *pd;63 struct resource *res;64 int size;65 int ret;66 67 pd = kzalloc(sizeof(struct simtec_i2c_data), GFP_KERNEL);68 if (pd == NULL)69 return -ENOMEM;70 71 platform_set_drvdata(dev, pd);72 73 res = platform_get_resource(dev, IORESOURCE_MEM, 0);74 if (res == NULL) {75 dev_err(&dev->dev, "cannot find IO resource\n");76 ret = -ENOENT;77 goto err;78 }79 80 size = resource_size(res);81 82 pd->ioarea = request_mem_region(res->start, size, dev->name);83 if (pd->ioarea == NULL) {84 dev_err(&dev->dev, "cannot request IO\n");85 ret = -ENXIO;86 goto err;87 }88 89 pd->reg = ioremap(res->start, size);90 if (pd->reg == NULL) {91 dev_err(&dev->dev, "cannot map IO\n");92 ret = -ENXIO;93 goto err_res;94 }95 96 /* setup the private data */97 98 pd->adap.owner = THIS_MODULE;99 pd->adap.algo_data = &pd->bit;100 pd->adap.dev.parent = &dev->dev;101 102 strscpy(pd->adap.name, "Simtec I2C", sizeof(pd->adap.name));103 104 pd->bit.data = pd;105 pd->bit.setsda = simtec_i2c_setsda;106 pd->bit.setscl = simtec_i2c_setscl;107 pd->bit.getsda = simtec_i2c_getsda;108 pd->bit.getscl = simtec_i2c_getscl;109 pd->bit.timeout = HZ;110 pd->bit.udelay = 20;111 112 ret = i2c_bit_add_bus(&pd->adap);113 if (ret)114 goto err_all;115 116 return 0;117 118 err_all:119 iounmap(pd->reg);120 121 err_res:122 release_mem_region(pd->ioarea->start, size);123 124 err:125 kfree(pd);126 return ret;127}128 129static void simtec_i2c_remove(struct platform_device *dev)130{131 struct simtec_i2c_data *pd = platform_get_drvdata(dev);132 133 i2c_del_adapter(&pd->adap);134 135 iounmap(pd->reg);136 release_mem_region(pd->ioarea->start, resource_size(pd->ioarea));137 kfree(pd);138}139 140/* device driver */141 142static struct platform_driver simtec_i2c_driver = {143 .driver = {144 .name = "simtec-i2c",145 },146 .probe = simtec_i2c_probe,147 .remove_new = simtec_i2c_remove,148};149 150module_platform_driver(simtec_i2c_driver);151 152MODULE_DESCRIPTION("Simtec Generic I2C Bus driver");153MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");154MODULE_LICENSE("GPL");155MODULE_ALIAS("platform:simtec-i2c");156