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 	struct resource *r;
68 	int ret;
69 
70 	i2c = devm_kzalloc(&dev->dev, sizeof(struct i2c_versatile), GFP_KERNEL);
71 	if (!i2c)
72 		return -ENOMEM;
73 
74 	r = platform_get_resource(dev, IORESOURCE_MEM, 0);
75 	i2c->base = devm_ioremap_resource(&dev->dev, r);
76 	if (IS_ERR(i2c->base))
77 		return PTR_ERR(i2c->base);
78 
79 	writel(SCL | SDA, i2c->base + I2C_CONTROLS);
80 
81 	i2c->adap.owner = THIS_MODULE;
82 	strscpy(i2c->adap.name, "Versatile I2C adapter", sizeof(i2c->adap.name));
83 	i2c->adap.algo_data = &i2c->algo;
84 	i2c->adap.dev.parent = &dev->dev;
85 	i2c->adap.dev.of_node = dev->dev.of_node;
86 	i2c->algo = i2c_versatile_algo;
87 	i2c->algo.data = i2c;
88 
89 	i2c->adap.nr = dev->id;
90 	ret = i2c_bit_add_numbered_bus(&i2c->adap);
91 	if (ret < 0)
92 		return ret;
93 
94 	platform_set_drvdata(dev, i2c);
95 
96 	return 0;
97 }
98 
99 static int i2c_versatile_remove(struct platform_device *dev)
100 {
101 	struct i2c_versatile *i2c = platform_get_drvdata(dev);
102 
103 	i2c_del_adapter(&i2c->adap);
104 	return 0;
105 }
106 
107 static const struct of_device_id i2c_versatile_match[] = {
108 	{ .compatible = "arm,versatile-i2c", },
109 	{},
110 };
111 MODULE_DEVICE_TABLE(of, i2c_versatile_match);
112 
113 static struct platform_driver i2c_versatile_driver = {
114 	.probe		= i2c_versatile_probe,
115 	.remove		= i2c_versatile_remove,
116 	.driver		= {
117 		.name	= "versatile-i2c",
118 		.of_match_table = i2c_versatile_match,
119 	},
120 };
121 
122 static int __init i2c_versatile_init(void)
123 {
124 	return platform_driver_register(&i2c_versatile_driver);
125 }
126 
127 static void __exit i2c_versatile_exit(void)
128 {
129 	platform_driver_unregister(&i2c_versatile_driver);
130 }
131 
132 subsys_initcall(i2c_versatile_init);
133 module_exit(i2c_versatile_exit);
134 
135 MODULE_DESCRIPTION("ARM Versatile I2C bus driver");
136 MODULE_LICENSE("GPL");
137 MODULE_ALIAS("platform:versatile-i2c");
138