1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Copyright (C) 2005 Simtec Electronics
4*4882a593Smuzhiyun * Ben Dooks <ben@simtec.co.uk>
5*4882a593Smuzhiyun *
6*4882a593Smuzhiyun * Simtec Generic I2C Controller
7*4882a593Smuzhiyun */
8*4882a593Smuzhiyun
9*4882a593Smuzhiyun #include <linux/kernel.h>
10*4882a593Smuzhiyun #include <linux/module.h>
11*4882a593Smuzhiyun #include <linux/delay.h>
12*4882a593Smuzhiyun #include <linux/platform_device.h>
13*4882a593Smuzhiyun #include <linux/slab.h>
14*4882a593Smuzhiyun #include <linux/io.h>
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun #include <linux/i2c.h>
17*4882a593Smuzhiyun #include <linux/i2c-algo-bit.h>
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun struct simtec_i2c_data {
20*4882a593Smuzhiyun struct resource *ioarea;
21*4882a593Smuzhiyun void __iomem *reg;
22*4882a593Smuzhiyun struct i2c_adapter adap;
23*4882a593Smuzhiyun struct i2c_algo_bit_data bit;
24*4882a593Smuzhiyun };
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun #define CMD_SET_SDA (1<<2)
27*4882a593Smuzhiyun #define CMD_SET_SCL (1<<3)
28*4882a593Smuzhiyun
29*4882a593Smuzhiyun #define STATE_SDA (1<<0)
30*4882a593Smuzhiyun #define STATE_SCL (1<<1)
31*4882a593Smuzhiyun
32*4882a593Smuzhiyun /* i2c bit-bus functions */
33*4882a593Smuzhiyun
simtec_i2c_setsda(void * pw,int state)34*4882a593Smuzhiyun static void simtec_i2c_setsda(void *pw, int state)
35*4882a593Smuzhiyun {
36*4882a593Smuzhiyun struct simtec_i2c_data *pd = pw;
37*4882a593Smuzhiyun writeb(CMD_SET_SDA | (state ? STATE_SDA : 0), pd->reg);
38*4882a593Smuzhiyun }
39*4882a593Smuzhiyun
simtec_i2c_setscl(void * pw,int state)40*4882a593Smuzhiyun static void simtec_i2c_setscl(void *pw, int state)
41*4882a593Smuzhiyun {
42*4882a593Smuzhiyun struct simtec_i2c_data *pd = pw;
43*4882a593Smuzhiyun writeb(CMD_SET_SCL | (state ? STATE_SCL : 0), pd->reg);
44*4882a593Smuzhiyun }
45*4882a593Smuzhiyun
simtec_i2c_getsda(void * pw)46*4882a593Smuzhiyun static int simtec_i2c_getsda(void *pw)
47*4882a593Smuzhiyun {
48*4882a593Smuzhiyun struct simtec_i2c_data *pd = pw;
49*4882a593Smuzhiyun return readb(pd->reg) & STATE_SDA ? 1 : 0;
50*4882a593Smuzhiyun }
51*4882a593Smuzhiyun
simtec_i2c_getscl(void * pw)52*4882a593Smuzhiyun static int simtec_i2c_getscl(void *pw)
53*4882a593Smuzhiyun {
54*4882a593Smuzhiyun struct simtec_i2c_data *pd = pw;
55*4882a593Smuzhiyun return readb(pd->reg) & STATE_SCL ? 1 : 0;
56*4882a593Smuzhiyun }
57*4882a593Smuzhiyun
58*4882a593Smuzhiyun /* device registration */
59*4882a593Smuzhiyun
simtec_i2c_probe(struct platform_device * dev)60*4882a593Smuzhiyun static int simtec_i2c_probe(struct platform_device *dev)
61*4882a593Smuzhiyun {
62*4882a593Smuzhiyun struct simtec_i2c_data *pd;
63*4882a593Smuzhiyun struct resource *res;
64*4882a593Smuzhiyun int size;
65*4882a593Smuzhiyun int ret;
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun pd = kzalloc(sizeof(struct simtec_i2c_data), GFP_KERNEL);
68*4882a593Smuzhiyun if (pd == NULL)
69*4882a593Smuzhiyun return -ENOMEM;
70*4882a593Smuzhiyun
71*4882a593Smuzhiyun platform_set_drvdata(dev, pd);
72*4882a593Smuzhiyun
73*4882a593Smuzhiyun res = platform_get_resource(dev, IORESOURCE_MEM, 0);
74*4882a593Smuzhiyun if (res == NULL) {
75*4882a593Smuzhiyun dev_err(&dev->dev, "cannot find IO resource\n");
76*4882a593Smuzhiyun ret = -ENOENT;
77*4882a593Smuzhiyun goto err;
78*4882a593Smuzhiyun }
79*4882a593Smuzhiyun
80*4882a593Smuzhiyun size = resource_size(res);
81*4882a593Smuzhiyun
82*4882a593Smuzhiyun pd->ioarea = request_mem_region(res->start, size, dev->name);
83*4882a593Smuzhiyun if (pd->ioarea == NULL) {
84*4882a593Smuzhiyun dev_err(&dev->dev, "cannot request IO\n");
85*4882a593Smuzhiyun ret = -ENXIO;
86*4882a593Smuzhiyun goto err;
87*4882a593Smuzhiyun }
88*4882a593Smuzhiyun
89*4882a593Smuzhiyun pd->reg = ioremap(res->start, size);
90*4882a593Smuzhiyun if (pd->reg == NULL) {
91*4882a593Smuzhiyun dev_err(&dev->dev, "cannot map IO\n");
92*4882a593Smuzhiyun ret = -ENXIO;
93*4882a593Smuzhiyun goto err_res;
94*4882a593Smuzhiyun }
95*4882a593Smuzhiyun
96*4882a593Smuzhiyun /* setup the private data */
97*4882a593Smuzhiyun
98*4882a593Smuzhiyun pd->adap.owner = THIS_MODULE;
99*4882a593Smuzhiyun pd->adap.algo_data = &pd->bit;
100*4882a593Smuzhiyun pd->adap.dev.parent = &dev->dev;
101*4882a593Smuzhiyun
102*4882a593Smuzhiyun strlcpy(pd->adap.name, "Simtec I2C", sizeof(pd->adap.name));
103*4882a593Smuzhiyun
104*4882a593Smuzhiyun pd->bit.data = pd;
105*4882a593Smuzhiyun pd->bit.setsda = simtec_i2c_setsda;
106*4882a593Smuzhiyun pd->bit.setscl = simtec_i2c_setscl;
107*4882a593Smuzhiyun pd->bit.getsda = simtec_i2c_getsda;
108*4882a593Smuzhiyun pd->bit.getscl = simtec_i2c_getscl;
109*4882a593Smuzhiyun pd->bit.timeout = HZ;
110*4882a593Smuzhiyun pd->bit.udelay = 20;
111*4882a593Smuzhiyun
112*4882a593Smuzhiyun ret = i2c_bit_add_bus(&pd->adap);
113*4882a593Smuzhiyun if (ret)
114*4882a593Smuzhiyun goto err_all;
115*4882a593Smuzhiyun
116*4882a593Smuzhiyun return 0;
117*4882a593Smuzhiyun
118*4882a593Smuzhiyun err_all:
119*4882a593Smuzhiyun iounmap(pd->reg);
120*4882a593Smuzhiyun
121*4882a593Smuzhiyun err_res:
122*4882a593Smuzhiyun release_mem_region(pd->ioarea->start, size);
123*4882a593Smuzhiyun
124*4882a593Smuzhiyun err:
125*4882a593Smuzhiyun kfree(pd);
126*4882a593Smuzhiyun return ret;
127*4882a593Smuzhiyun }
128*4882a593Smuzhiyun
simtec_i2c_remove(struct platform_device * dev)129*4882a593Smuzhiyun static int simtec_i2c_remove(struct platform_device *dev)
130*4882a593Smuzhiyun {
131*4882a593Smuzhiyun struct simtec_i2c_data *pd = platform_get_drvdata(dev);
132*4882a593Smuzhiyun
133*4882a593Smuzhiyun i2c_del_adapter(&pd->adap);
134*4882a593Smuzhiyun
135*4882a593Smuzhiyun iounmap(pd->reg);
136*4882a593Smuzhiyun release_mem_region(pd->ioarea->start, resource_size(pd->ioarea));
137*4882a593Smuzhiyun kfree(pd);
138*4882a593Smuzhiyun
139*4882a593Smuzhiyun return 0;
140*4882a593Smuzhiyun }
141*4882a593Smuzhiyun
142*4882a593Smuzhiyun /* device driver */
143*4882a593Smuzhiyun
144*4882a593Smuzhiyun static struct platform_driver simtec_i2c_driver = {
145*4882a593Smuzhiyun .driver = {
146*4882a593Smuzhiyun .name = "simtec-i2c",
147*4882a593Smuzhiyun },
148*4882a593Smuzhiyun .probe = simtec_i2c_probe,
149*4882a593Smuzhiyun .remove = simtec_i2c_remove,
150*4882a593Smuzhiyun };
151*4882a593Smuzhiyun
152*4882a593Smuzhiyun module_platform_driver(simtec_i2c_driver);
153*4882a593Smuzhiyun
154*4882a593Smuzhiyun MODULE_DESCRIPTION("Simtec Generic I2C Bus driver");
155*4882a593Smuzhiyun MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
156*4882a593Smuzhiyun MODULE_LICENSE("GPL");
157*4882a593Smuzhiyun MODULE_ALIAS("platform:simtec-i2c");
158