1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Coral-P(A)/Lime I2C adapter driver
4 *
5 * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
6 */
7
8 #include <linux/fb.h>
9 #include <linux/i2c.h>
10 #include <linux/io.h>
11 #include <linux/delay.h>
12
13 #include "mb862xxfb.h"
14 #include "mb862xx_reg.h"
15
mb862xx_i2c_wait_event(struct i2c_adapter * adap)16 static int mb862xx_i2c_wait_event(struct i2c_adapter *adap)
17 {
18 struct mb862xxfb_par *par = adap->algo_data;
19 u32 reg;
20
21 do {
22 udelay(10);
23 reg = inreg(i2c, GC_I2C_BCR);
24 if (reg & (I2C_INT | I2C_BER))
25 break;
26 } while (1);
27
28 return (reg & I2C_BER) ? 0 : 1;
29 }
30
mb862xx_i2c_do_address(struct i2c_adapter * adap,int addr)31 static int mb862xx_i2c_do_address(struct i2c_adapter *adap, int addr)
32 {
33 struct mb862xxfb_par *par = adap->algo_data;
34
35 outreg(i2c, GC_I2C_DAR, addr);
36 outreg(i2c, GC_I2C_CCR, I2C_CLOCK_AND_ENABLE);
37 outreg(i2c, GC_I2C_BCR, par->i2c_rs ? I2C_REPEATED_START : I2C_START);
38 if (!mb862xx_i2c_wait_event(adap))
39 return -EIO;
40 par->i2c_rs = !(inreg(i2c, GC_I2C_BSR) & I2C_LRB);
41 return par->i2c_rs;
42 }
43
mb862xx_i2c_write_byte(struct i2c_adapter * adap,u8 byte)44 static int mb862xx_i2c_write_byte(struct i2c_adapter *adap, u8 byte)
45 {
46 struct mb862xxfb_par *par = adap->algo_data;
47
48 outreg(i2c, GC_I2C_DAR, byte);
49 outreg(i2c, GC_I2C_BCR, I2C_START);
50 if (!mb862xx_i2c_wait_event(adap))
51 return -EIO;
52 return !(inreg(i2c, GC_I2C_BSR) & I2C_LRB);
53 }
54
mb862xx_i2c_read_byte(struct i2c_adapter * adap,u8 * byte,int last)55 static int mb862xx_i2c_read_byte(struct i2c_adapter *adap, u8 *byte, int last)
56 {
57 struct mb862xxfb_par *par = adap->algo_data;
58
59 outreg(i2c, GC_I2C_BCR, I2C_START | (last ? 0 : I2C_ACK));
60 if (!mb862xx_i2c_wait_event(adap))
61 return 0;
62 *byte = inreg(i2c, GC_I2C_DAR);
63 return 1;
64 }
65
mb862xx_i2c_stop(struct i2c_adapter * adap)66 static void mb862xx_i2c_stop(struct i2c_adapter *adap)
67 {
68 struct mb862xxfb_par *par = adap->algo_data;
69
70 outreg(i2c, GC_I2C_BCR, I2C_STOP);
71 outreg(i2c, GC_I2C_CCR, I2C_DISABLE);
72 par->i2c_rs = 0;
73 }
74
mb862xx_i2c_read(struct i2c_adapter * adap,struct i2c_msg * m)75 static int mb862xx_i2c_read(struct i2c_adapter *adap, struct i2c_msg *m)
76 {
77 int i, ret = 0;
78 int last = m->len - 1;
79
80 for (i = 0; i < m->len; i++) {
81 if (!mb862xx_i2c_read_byte(adap, &m->buf[i], i == last)) {
82 ret = -EIO;
83 break;
84 }
85 }
86 return ret;
87 }
88
mb862xx_i2c_write(struct i2c_adapter * adap,struct i2c_msg * m)89 static int mb862xx_i2c_write(struct i2c_adapter *adap, struct i2c_msg *m)
90 {
91 int i, ret = 0;
92
93 for (i = 0; i < m->len; i++) {
94 if (!mb862xx_i2c_write_byte(adap, m->buf[i])) {
95 ret = -EIO;
96 break;
97 }
98 }
99 return ret;
100 }
101
mb862xx_xfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)102 static int mb862xx_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
103 int num)
104 {
105 struct mb862xxfb_par *par = adap->algo_data;
106 struct i2c_msg *m;
107 int addr;
108 int i = 0, err = 0;
109
110 dev_dbg(par->dev, "%s: %d msgs\n", __func__, num);
111
112 for (i = 0; i < num; i++) {
113 m = &msgs[i];
114 if (!m->len) {
115 dev_dbg(par->dev, "%s: null msgs\n", __func__);
116 continue;
117 }
118 addr = m->addr;
119 if (m->flags & I2C_M_RD)
120 addr |= 1;
121
122 err = mb862xx_i2c_do_address(adap, addr);
123 if (err < 0)
124 break;
125 if (m->flags & I2C_M_RD)
126 err = mb862xx_i2c_read(adap, m);
127 else
128 err = mb862xx_i2c_write(adap, m);
129 }
130
131 if (i)
132 mb862xx_i2c_stop(adap);
133
134 return (err < 0) ? err : i;
135 }
136
mb862xx_func(struct i2c_adapter * adap)137 static u32 mb862xx_func(struct i2c_adapter *adap)
138 {
139 return I2C_FUNC_SMBUS_BYTE_DATA;
140 }
141
142 static const struct i2c_algorithm mb862xx_algo = {
143 .master_xfer = mb862xx_xfer,
144 .functionality = mb862xx_func,
145 };
146
147 static struct i2c_adapter mb862xx_i2c_adapter = {
148 .name = "MB862xx I2C adapter",
149 .algo = &mb862xx_algo,
150 .owner = THIS_MODULE,
151 };
152
mb862xx_i2c_init(struct mb862xxfb_par * par)153 int mb862xx_i2c_init(struct mb862xxfb_par *par)
154 {
155 mb862xx_i2c_adapter.algo_data = par;
156 par->adap = &mb862xx_i2c_adapter;
157
158 return i2c_add_adapter(par->adap);
159 }
160
mb862xx_i2c_exit(struct mb862xxfb_par * par)161 void mb862xx_i2c_exit(struct mb862xxfb_par *par)
162 {
163 if (par->adap) {
164 i2c_del_adapter(par->adap);
165 par->adap = NULL;
166 }
167 }
168