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
i2c_versatile_setsda(void * data,int state)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
i2c_versatile_setscl(void * data,int state)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
i2c_versatile_getsda(void * data)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
i2c_versatile_getscl(void * data)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
i2c_versatile_probe(struct platform_device * dev)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
i2c_versatile_remove(struct platform_device * dev)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
i2c_versatile_init(void)122 static int __init i2c_versatile_init(void)
123 {
124 return platform_driver_register(&i2c_versatile_driver);
125 }
126
i2c_versatile_exit(void)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