1/*
2 * Coral-P(A)/Lime I2C adapter driver
3 *
4 * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 */
11
12#include <linux/fb.h>
13#include <linux/i2c.h>
14#include <linux/io.h>
15#include <linux/delay.h>
16#include <linux/export.h>
17
18#include "mb862xxfb.h"
19#include "mb862xx_reg.h"
20
21static int mb862xx_i2c_wait_event(struct i2c_adapter *adap)
22{
23	struct mb862xxfb_par *par = adap->algo_data;
24	u32 reg;
25
26	do {
27		udelay(10);
28		reg = inreg(i2c, GC_I2C_BCR);
29		if (reg & (I2C_INT | I2C_BER))
30			break;
31	} while (1);
32
33	return (reg & I2C_BER) ? 0 : 1;
34}
35
36static int mb862xx_i2c_do_address(struct i2c_adapter *adap, int addr)
37{
38	struct mb862xxfb_par *par = adap->algo_data;
39
40	outreg(i2c, GC_I2C_DAR, addr);
41	outreg(i2c, GC_I2C_CCR, I2C_CLOCK_AND_ENABLE);
42	outreg(i2c, GC_I2C_BCR, par->i2c_rs ? I2C_REPEATED_START : I2C_START);
43	if (!mb862xx_i2c_wait_event(adap))
44		return -EIO;
45	par->i2c_rs = !(inreg(i2c, GC_I2C_BSR) & I2C_LRB);
46	return par->i2c_rs;
47}
48
49static int mb862xx_i2c_write_byte(struct i2c_adapter *adap, u8 byte)
50{
51	struct mb862xxfb_par *par = adap->algo_data;
52
53	outreg(i2c, GC_I2C_DAR, byte);
54	outreg(i2c, GC_I2C_BCR, I2C_START);
55	if (!mb862xx_i2c_wait_event(adap))
56		return -EIO;
57	return !(inreg(i2c, GC_I2C_BSR) & I2C_LRB);
58}
59
60static int mb862xx_i2c_read_byte(struct i2c_adapter *adap, u8 *byte, int last)
61{
62	struct mb862xxfb_par *par = adap->algo_data;
63
64	outreg(i2c, GC_I2C_BCR, I2C_START | (last ? 0 : I2C_ACK));
65	if (!mb862xx_i2c_wait_event(adap))
66		return 0;
67	*byte = inreg(i2c, GC_I2C_DAR);
68	return 1;
69}
70
71void mb862xx_i2c_stop(struct i2c_adapter *adap)
72{
73	struct mb862xxfb_par *par = adap->algo_data;
74
75	outreg(i2c, GC_I2C_BCR, I2C_STOP);
76	outreg(i2c, GC_I2C_CCR, I2C_DISABLE);
77	par->i2c_rs = 0;
78}
79
80static int mb862xx_i2c_read(struct i2c_adapter *adap, struct i2c_msg *m)
81{
82	int i, ret = 0;
83	int last = m->len - 1;
84
85	for (i = 0; i < m->len; i++) {
86		if (!mb862xx_i2c_read_byte(adap, &m->buf[i], i == last)) {
87			ret = -EIO;
88			break;
89		}
90	}
91	return ret;
92}
93
94static int mb862xx_i2c_write(struct i2c_adapter *adap, struct i2c_msg *m)
95{
96	int i, ret = 0;
97
98	for (i = 0; i < m->len; i++) {
99		if (!mb862xx_i2c_write_byte(adap, m->buf[i])) {
100			ret = -EIO;
101			break;
102		}
103	}
104	return ret;
105}
106
107static int mb862xx_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
108			int num)
109{
110	struct mb862xxfb_par *par = adap->algo_data;
111	struct i2c_msg *m;
112	int addr;
113	int i = 0, err = 0;
114
115	dev_dbg(par->dev, "%s: %d msgs\n", __func__, num);
116
117	for (i = 0; i < num; i++) {
118		m = &msgs[i];
119		if (!m->len) {
120			dev_dbg(par->dev, "%s: null msgs\n", __func__);
121			continue;
122		}
123		addr = m->addr;
124		if (m->flags & I2C_M_RD)
125			addr |= 1;
126
127		err = mb862xx_i2c_do_address(adap, addr);
128		if (err < 0)
129			break;
130		if (m->flags & I2C_M_RD)
131			err = mb862xx_i2c_read(adap, m);
132		else
133			err = mb862xx_i2c_write(adap, m);
134	}
135
136	if (i)
137		mb862xx_i2c_stop(adap);
138
139	return (err < 0) ? err : i;
140}
141
142static u32 mb862xx_func(struct i2c_adapter *adap)
143{
144	return I2C_FUNC_SMBUS_BYTE_DATA;
145}
146
147static const struct i2c_algorithm mb862xx_algo = {
148	.master_xfer	= mb862xx_xfer,
149	.functionality	= mb862xx_func,
150};
151
152static struct i2c_adapter mb862xx_i2c_adapter = {
153	.name		= "MB862xx I2C adapter",
154	.algo		= &mb862xx_algo,
155	.owner		= THIS_MODULE,
156};
157
158int mb862xx_i2c_init(struct mb862xxfb_par *par)
159{
160	int ret;
161
162	mb862xx_i2c_adapter.algo_data = par;
163	par->adap = &mb862xx_i2c_adapter;
164
165	ret = i2c_add_adapter(par->adap);
166	if (ret < 0) {
167		dev_err(par->dev, "failed to add %s\n",
168			mb862xx_i2c_adapter.name);
169	}
170	return ret;
171}
172
173void mb862xx_i2c_exit(struct mb862xxfb_par *par)
174{
175	if (par->adap) {
176		i2c_del_adapter(par->adap);
177		par->adap = NULL;
178	}
179}
180