aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/video/mb862xx/mb862xx-i2c.c
blob: b953099edd8eb491850fdd4ca65e6c9b3789cd39 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
/*
 * Coral-P(A)/Lime I2C adapter driver
 *
 * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/fb.h>
#include <linux/i2c.h>
#include <linux/io.h>
#include <linux/delay.h>

#include "mb862xxfb.h"
#include "mb862xx_reg.h"

static int mb862xx_i2c_wait_event(struct i2c_adapter *adap)
{
	struct mb862xxfb_par *par = adap->algo_data;
	u32 reg;

	do {
		udelay(1);
		reg = inreg(i2c, GC_I2C_BCR);
		if (reg & (I2C_INT | I2C_BER))
			break;
	} while (1);

	return (reg & I2C_BER) ? 0 : 1;
}

static int mb862xx_i2c_do_address(struct i2c_adapter *adap, int addr)
{
	struct mb862xxfb_par *par = adap->algo_data;

	outreg(i2c, GC_I2C_DAR, addr);
	outreg(i2c, GC_I2C_CCR, I2C_CLOCK_AND_ENABLE);
	outreg(i2c, GC_I2C_BCR, par->i2c_rs ? I2C_REPEATED_START : I2C_START);
	if (!mb862xx_i2c_wait_event(adap))
		return -EIO;
	par->i2c_rs = !(inreg(i2c, GC_I2C_BSR) & I2C_LRB);
	return par->i2c_rs;
}

static int mb862xx_i2c_write_byte(struct i2c_adapter *adap, u8 byte)
{
	struct mb862xxfb_par *par = adap->algo_data;

	outreg(i2c, GC_I2C_DAR, byte);
	outreg(i2c, GC_I2C_BCR, I2C_START);
	if (!mb862xx_i2c_wait_event(adap))
		return -EIO;
	return !(inreg(i2c, GC_I2C_BSR) & I2C_LRB);
}

static int mb862xx_i2c_read_byte(struct i2c_adapter *adap, u8 *byte, int last)
{
	struct mb862xxfb_par *par = adap->algo_data;

	outreg(i2c, GC_I2C_BCR, I2C_START | (last ? 0 : I2C_ACK));
	if (!mb862xx_i2c_wait_event(adap))
		return 0;
	*byte = inreg(i2c, GC_I2C_DAR);
	return 1;
}

void mb862xx_i2c_stop(struct i2c_adapter *adap)
{
	struct mb862xxfb_par *par = adap->algo_data;

	outreg(i2c, GC_I2C_BCR, I2C_STOP);
	outreg(i2c, GC_I2C_CCR, I2C_DISABLE);
	par->i2c_rs = 0;
}

static int mb862xx_i2c_read(struct i2c_adapter *adap, struct i2c_msg *m)
{
	int i, ret = 0;
	int last = m->len - 1;

	for (i = 0; i < m->len; i++) {
		if (!mb862xx_i2c_read_byte(adap, &m->buf[i], i == last)) {
			ret = -EIO;
			break;
		}
	}
	return ret;
}

static int mb862xx_i2c_write(struct i2c_adapter *adap, struct i2c_msg *m)
{
	int i, ret = 0;

	for (i = 0; i < m->len; i++) {
		if (!mb862xx_i2c_write_byte(adap, m->buf[i])) {
			ret = -EIO;
			break;
		}
	}
	return ret;
}

static int mb862xx_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
			int num)
{
	struct mb862xxfb_par *par = adap->algo_data;
	struct i2c_msg *m;
	int addr;
	int i = 0, err = 0;

	dev_dbg(par->dev, "%s: %d msgs\n", __func__, num);

	for (i = 0; i < num; i++) {
		m = &msgs[i];
		if (!m->len) {
			dev_dbg(par->dev, "%s: null msgs\n", __func__);
			continue;
		}
		addr = m->addr;
		if (m->flags & I2C_M_RD)
			addr |= 1;

		err = mb862xx_i2c_do_address(adap, addr);
		if (err < 0)
			break;
		if (m->flags & I2C_M_RD)
			err = mb862xx_i2c_read(adap, m);
		else
			err = mb862xx_i2c_write(adap, m);
	}

	if (i)
		mb862xx_i2c_stop(adap);

	return (err < 0) ? err : i;
}

static u32 mb862xx_func(struct i2c_adapter *adap)
{
	return I2C_FUNC_SMBUS_BYTE_DATA;
}

static const struct i2c_algorithm mb862xx_algo = {
	.master_xfer	= mb862xx_xfer,
	.functionality	= mb862xx_func,
};

static struct i2c_adapter mb862xx_i2c_adapter = {
	.name		= "MB862xx I2C adapter",
	.algo		= &mb862xx_algo,
	.owner		= THIS_MODULE,
};

int mb862xx_i2c_init(struct mb862xxfb_par *par)
{
	int ret;

	mb862xx_i2c_adapter.algo_data = par;
	par->adap = &mb862xx_i2c_adapter;

	ret = i2c_add_adapter(par->adap);
	if (ret < 0) {
		dev_err(par->dev, "failed to add %s\n",
			mb862xx_i2c_adapter.name);
	}
	return ret;
}

void mb862xx_i2c_exit(struct mb862xxfb_par *par)
{
	if (par->adap) {
		i2c_del_adapter(par->adap);
		par->adap = NULL;
	}
}