soft_spi_legacy.c
3.77 KB
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
/*
* (C) Copyright 2002
* Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
*
* Influenced by code from:
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <spi.h>
#include <malloc.h>
/*-----------------------------------------------------------------------
* Definitions
*/
#ifdef DEBUG_SPI
#define PRINTD(fmt,args...) printf (fmt ,##args)
#else
#define PRINTD(fmt,args...)
#endif
struct soft_spi_slave {
struct spi_slave slave;
unsigned int mode;
};
static inline struct soft_spi_slave *to_soft_spi(struct spi_slave *slave)
{
return container_of(slave, struct soft_spi_slave, slave);
}
/*=====================================================================*/
/* Public Functions */
/*=====================================================================*/
/*-----------------------------------------------------------------------
* Initialization
*/
void spi_init (void)
{
}
struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
unsigned int max_hz, unsigned int mode)
{
struct soft_spi_slave *ss;
if (!spi_cs_is_valid(bus, cs))
return NULL;
ss = spi_alloc_slave(struct soft_spi_slave, bus, cs);
if (!ss)
return NULL;
ss->mode = mode;
/* TODO: Use max_hz to limit the SCK rate */
return &ss->slave;
}
void spi_free_slave(struct spi_slave *slave)
{
struct soft_spi_slave *ss = to_soft_spi(slave);
free(ss);
}
int spi_claim_bus(struct spi_slave *slave)
{
#ifdef CONFIG_SYS_IMMR
volatile immap_t *immr = (immap_t *)CONFIG_SYS_IMMR;
#endif
struct soft_spi_slave *ss = to_soft_spi(slave);
/*
* Make sure the SPI clock is in idle state as defined for
* this slave.
*/
if (ss->mode & SPI_CPOL)
SPI_SCL(1);
else
SPI_SCL(0);
return 0;
}
void spi_release_bus(struct spi_slave *slave)
{
/* Nothing to do */
}
/*-----------------------------------------------------------------------
* SPI transfer
*
* This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks
* "bitlen" bits in the SPI MISO port. That's just the way SPI works.
*
* The source of the outgoing bits is the "dout" parameter and the
* destination of the input bits is the "din" parameter. Note that "dout"
* and "din" can point to the same memory location, in which case the
* input data overwrites the output data (since both are buffered by
* temporary variables, this is OK).
*/
int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
const void *dout, void *din, unsigned long flags)
{
#ifdef CONFIG_SYS_IMMR
volatile immap_t *immr = (immap_t *)CONFIG_SYS_IMMR;
#endif
struct soft_spi_slave *ss = to_soft_spi(slave);
uchar tmpdin = 0;
uchar tmpdout = 0;
const u8 *txd = dout;
u8 *rxd = din;
int cpol = ss->mode & SPI_CPOL;
int cpha = ss->mode & SPI_CPHA;
unsigned int j;
PRINTD("spi_xfer: slave %u:%u dout %08X din %08X bitlen %u\n",
slave->bus, slave->cs, *(uint *)txd, *(uint *)rxd, bitlen);
if (flags & SPI_XFER_BEGIN)
spi_cs_activate(slave);
for(j = 0; j < bitlen; j++) {
/*
* Check if it is time to work on a new byte.
*/
if ((j % 8) == 0) {
if (txd)
tmpdout = *txd++;
else
tmpdout = 0;
if(j != 0) {
if (rxd)
*rxd++ = tmpdin;
}
tmpdin = 0;
}
if (!cpha)
SPI_SCL(!cpol);
SPI_SDA(tmpdout & 0x80);
SPI_DELAY;
if (cpha)
SPI_SCL(!cpol);
else
SPI_SCL(cpol);
tmpdin <<= 1;
tmpdin |= SPI_READ;
tmpdout <<= 1;
SPI_DELAY;
if (cpha)
SPI_SCL(cpol);
}
/*
* If the number of bits isn't a multiple of 8, shift the last
* bits over to left-justify them. Then store the last byte
* read in.
*/
if (rxd) {
if ((bitlen % 8) != 0)
tmpdin <<= 8 - (bitlen % 8);
*rxd++ = tmpdin;
}
if (flags & SPI_XFER_END)
spi_cs_deactivate(slave);
return(0);
}