LXR linux/drivers/i2c/busses/i2c-simtec.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (C) 2005 Simtec Electronics
   4 *      Ben Dooks <ben@simtec.co.uk>
   5 *
   6 * Simtec Generic I2C Controller
   7*/
   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        strlcpy(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 int 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        return 0;
 140}
 141
 142/* device driver */
 143
 144static struct platform_driver simtec_i2c_driver = {
 145        .driver         = {
 146                .name           = "simtec-i2c",
 147        },
 148        .probe          = simtec_i2c_probe,
 149        .remove         = simtec_i2c_remove,
 150};
 151
 152module_platform_driver(simtec_i2c_driver);
 153
 154MODULE_DESCRIPTION("Simtec Generic I2C Bus driver");
 155MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 156MODULE_LICENSE("GPL");
 157MODULE_ALIAS("platform:simtec-i2c");
 158