1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * ARM IOC/IOMD i2c driver.
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright (C) 2000 Russell King
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * On Acorn machines, the following i2c devices are on the bus:
8*4882a593Smuzhiyun * - PCF8583 real time clock & static RAM
9*4882a593Smuzhiyun */
10*4882a593Smuzhiyun #include <linux/module.h>
11*4882a593Smuzhiyun #include <linux/i2c.h>
12*4882a593Smuzhiyun #include <linux/i2c-algo-bit.h>
13*4882a593Smuzhiyun #include <linux/io.h>
14*4882a593Smuzhiyun
15*4882a593Smuzhiyun #include <mach/hardware.h>
16*4882a593Smuzhiyun #include <asm/hardware/ioc.h>
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun #define FORCE_ONES 0xdc
19*4882a593Smuzhiyun #define SCL 0x02
20*4882a593Smuzhiyun #define SDA 0x01
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun /*
23*4882a593Smuzhiyun * We must preserve all non-i2c output bits in IOC_CONTROL.
24*4882a593Smuzhiyun * Note also that we need to preserve the value of SCL and
25*4882a593Smuzhiyun * SDA outputs as well (which may be different from the
26*4882a593Smuzhiyun * values read back from IOC_CONTROL).
27*4882a593Smuzhiyun */
28*4882a593Smuzhiyun static u_int force_ones;
29*4882a593Smuzhiyun
ioc_setscl(void * data,int state)30*4882a593Smuzhiyun static void ioc_setscl(void *data, int state)
31*4882a593Smuzhiyun {
32*4882a593Smuzhiyun u_int ioc_control = ioc_readb(IOC_CONTROL) & ~(SCL | SDA);
33*4882a593Smuzhiyun u_int ones = force_ones;
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun if (state)
36*4882a593Smuzhiyun ones |= SCL;
37*4882a593Smuzhiyun else
38*4882a593Smuzhiyun ones &= ~SCL;
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun force_ones = ones;
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun ioc_writeb(ioc_control | ones, IOC_CONTROL);
43*4882a593Smuzhiyun }
44*4882a593Smuzhiyun
ioc_setsda(void * data,int state)45*4882a593Smuzhiyun static void ioc_setsda(void *data, int state)
46*4882a593Smuzhiyun {
47*4882a593Smuzhiyun u_int ioc_control = ioc_readb(IOC_CONTROL) & ~(SCL | SDA);
48*4882a593Smuzhiyun u_int ones = force_ones;
49*4882a593Smuzhiyun
50*4882a593Smuzhiyun if (state)
51*4882a593Smuzhiyun ones |= SDA;
52*4882a593Smuzhiyun else
53*4882a593Smuzhiyun ones &= ~SDA;
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun force_ones = ones;
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun ioc_writeb(ioc_control | ones, IOC_CONTROL);
58*4882a593Smuzhiyun }
59*4882a593Smuzhiyun
ioc_getscl(void * data)60*4882a593Smuzhiyun static int ioc_getscl(void *data)
61*4882a593Smuzhiyun {
62*4882a593Smuzhiyun return (ioc_readb(IOC_CONTROL) & SCL) != 0;
63*4882a593Smuzhiyun }
64*4882a593Smuzhiyun
ioc_getsda(void * data)65*4882a593Smuzhiyun static int ioc_getsda(void *data)
66*4882a593Smuzhiyun {
67*4882a593Smuzhiyun return (ioc_readb(IOC_CONTROL) & SDA) != 0;
68*4882a593Smuzhiyun }
69*4882a593Smuzhiyun
70*4882a593Smuzhiyun static struct i2c_algo_bit_data ioc_data = {
71*4882a593Smuzhiyun .setsda = ioc_setsda,
72*4882a593Smuzhiyun .setscl = ioc_setscl,
73*4882a593Smuzhiyun .getsda = ioc_getsda,
74*4882a593Smuzhiyun .getscl = ioc_getscl,
75*4882a593Smuzhiyun .udelay = 80,
76*4882a593Smuzhiyun .timeout = HZ,
77*4882a593Smuzhiyun };
78*4882a593Smuzhiyun
79*4882a593Smuzhiyun static struct i2c_adapter ioc_ops = {
80*4882a593Smuzhiyun .nr = 0,
81*4882a593Smuzhiyun .name = "ioc",
82*4882a593Smuzhiyun .algo_data = &ioc_data,
83*4882a593Smuzhiyun };
84*4882a593Smuzhiyun
i2c_ioc_init(void)85*4882a593Smuzhiyun static int __init i2c_ioc_init(void)
86*4882a593Smuzhiyun {
87*4882a593Smuzhiyun force_ones = FORCE_ONES | SCL | SDA;
88*4882a593Smuzhiyun
89*4882a593Smuzhiyun return i2c_bit_add_numbered_bus(&ioc_ops);
90*4882a593Smuzhiyun }
91*4882a593Smuzhiyun
92*4882a593Smuzhiyun module_init(i2c_ioc_init);
93*4882a593Smuzhiyun
94*4882a593Smuzhiyun MODULE_AUTHOR("Russell King <linux@armlinux.org.uk>");
95*4882a593Smuzhiyun MODULE_DESCRIPTION("ARM IOC/IOMD i2c driver");
96*4882a593Smuzhiyun MODULE_LICENSE("GPL v2");
97