drivers/i2c/busses/i2c-versatile.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  i2c-versatile.c
   4  *
   5  *  Copyright (C) 2006 ARM Ltd.
   6  *  written by Russell King, Deep Blue Solutions Ltd.
   7  */
   8 #include <linux/kernel.h>
   9 #include <linux/module.h>
  10 #include <linux/i2c.h>
  11 #include <linux/i2c-algo-bit.h>
  12 #include <linux/init.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/slab.h>
  15 #include <linux/io.h>
  16
  17 #define I2C_CONTROL     0x00
  18 #define I2C_CONTROLS    0x00
  19 #define I2C_CONTROLC    0x04
  20 #define SCL             (1 << 0)
  21 #define SDA             (1 << 1)
  22
  23 struct i2c_versatile {
  24         struct i2c_adapter       adap;
  25         struct i2c_algo_bit_data algo;
  26         void __iomem             *base;
  27 };
  28
  29 static void i2c_versatile_setsda(void *data, int state)
  30 {
  31         struct i2c_versatile *i2c = data;
  32
  33         writel(SDA, i2c->base + (state ? I2C_CONTROLS : I2C_CONTROLC));
  34 }
  35
  36 static void i2c_versatile_setscl(void *data, int state)
  37 {
  38         struct i2c_versatile *i2c = data;
  39
  40         writel(SCL, i2c->base + (state ? I2C_CONTROLS : I2C_CONTROLC));
  41 }
  42
  43 static int i2c_versatile_getsda(void *data)
  44 {
  45         struct i2c_versatile *i2c = data;
  46         return !!(readl(i2c->base + I2C_CONTROL) & SDA);
  47 }
  48
  49 static int i2c_versatile_getscl(void *data)
  50 {
  51         struct i2c_versatile *i2c = data;
  52         return !!(readl(i2c->base + I2C_CONTROL) & SCL);
  53 }
  54
  55 static const struct i2c_algo_bit_data i2c_versatile_algo = {
  56         .setsda = i2c_versatile_setsda,
  57         .setscl = i2c_versatile_setscl,
  58         .getsda = i2c_versatile_getsda,
  59         .getscl = i2c_versatile_getscl,
  60         .udelay = 30,
  61         .timeout = HZ,
  62 };
  63
  64 static int i2c_versatile_probe(struct platform_device *dev)
  65 {
  66         struct i2c_versatile *i2c;
  67         int ret;
  68
  69         i2c = devm_kzalloc(&dev->dev, sizeof(struct i2c_versatile), GFP_KERNEL);
  70         if (!i2c)
  71                 return -ENOMEM;
  72
  73         i2c->base = devm_platform_get_and_ioremap_resource(dev, 0, NULL);
  74         if (IS_ERR(i2c->base))
  75                 return PTR_ERR(i2c->base);
  76
  77         writel(SCL | SDA, i2c->base + I2C_CONTROLS);
  78
  79         i2c->adap.owner = THIS_MODULE;
  80         strscpy(i2c->adap.name, "Versatile I2C adapter", sizeof(i2c->adap.name));
  81         i2c->adap.algo_data = &i2c->algo;
  82         i2c->adap.dev.parent = &dev->dev;
  83         i2c->adap.dev.of_node = dev->dev.of_node;
  84         i2c->algo = i2c_versatile_algo;
  85         i2c->algo.data = i2c;
  86
  87         i2c->adap.nr = dev->id;
  88         ret = i2c_bit_add_numbered_bus(&i2c->adap);
  89         if (ret < 0)
  90                 return ret;
  91
  92         platform_set_drvdata(dev, i2c);
  93
  94         return 0;
  95 }
  96
  97 static void i2c_versatile_remove(struct platform_device *dev)
  98 {
  99         struct i2c_versatile *i2c = platform_get_drvdata(dev);
 100
 101         i2c_del_adapter(&i2c->adap);
 102 }
 103
 104 static const struct of_device_id i2c_versatile_match[] = {
 105         { .compatible = "arm,versatile-i2c", },
 106         {},
 107 };
 108 MODULE_DEVICE_TABLE(of, i2c_versatile_match);
 109
 110 static struct platform_driver i2c_versatile_driver = {
 111         .probe          = i2c_versatile_probe,
 112         .remove         = i2c_versatile_remove,
 113         .driver         = {
 114                 .name   = "versatile-i2c",
 115                 .of_match_table = i2c_versatile_match,
 116         },
 117 };
 118
 119 static int __init i2c_versatile_init(void)
 120 {
 121         return platform_driver_register(&i2c_versatile_driver);
 122 }
 123
 124 static void __exit i2c_versatile_exit(void)
 125 {
 126         platform_driver_unregister(&i2c_versatile_driver);
 127 }
 128
 129 subsys_initcall(i2c_versatile_init);
 130 module_exit(i2c_versatile_exit);
 131
 132 MODULE_DESCRIPTION("ARM Versatile I2C bus driver");
 133 MODULE_LICENSE("GPL");
 134 MODULE_ALIAS("platform:versatile-i2c");