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
  19 struct 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
  34 static 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
  40 static 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
  46 static 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
  52 static 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
  60 static 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
 129 static 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
 144 static 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
 152 module_platform_driver(simtec_i2c_driver);
 153
 154 MODULE_DESCRIPTION("Simtec Generic I2C Bus driver");
 155 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 156 MODULE_LICENSE("GPL");
 157 MODULE_ALIAS("platform:simtec-i2c");