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
179
|
/*
* (C) Copyright 2001
* Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#ifndef _SPI_GENERIC_H_
#define _SPI_GENERIC_H_
#include <stdint.h>
/* Controller-specific definitions: */
/* SPI opcodes */
#define SPI_OPCODE_WREN 0x06
#define SPI_OPCODE_FAST_READ 0x0b
#define SPI_READ_FLAG 0x01
#define SPI_WRITE_FLAG 0x02
/*-----------------------------------------------------------------------
* Representation of a SPI slave, i.e. what we're communicating with.
*
* Drivers are expected to extend this with controller-specific data.
*
* bus: ID of the bus that the slave is attached to.
* cs: ID of the chip select connected to the slave.
* rw: Read or Write flag
*/
struct spi_slave {
unsigned int bus;
unsigned int cs;
unsigned int rw;
int force_programmer_specific;
struct spi_flash * (*programmer_specific_probe) (struct spi_slave *spi);
};
/*-----------------------------------------------------------------------
* Initialization, must be called once on start up.
*
*/
void spi_init(void);
/*-----------------------------------------------------------------------
* Set up communications parameters for a SPI slave.
*
* This must be called once for each slave. Note that this function
* usually doesn't touch any actual hardware, it only initializes the
* contents of spi_slave so that the hardware can be easily
* initialized later.
*
* bus: Bus ID of the slave chip.
* cs: Chip select ID of the slave chip on the specified bus.
*
* Returns: A spi_slave reference that can be used in subsequent SPI
* calls, or NULL if one or more of the parameters are not supported.
*/
struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs);
/*-----------------------------------------------------------------------
* Claim the bus and prepare it for communication with a given slave.
*
* This must be called before doing any transfers with a SPI slave. It
* will enable and initialize any SPI hardware as necessary, and make
* sure that the SCK line is in the correct idle state. It is not
* allowed to claim the same bus for several slaves without releasing
* the bus in between.
*
* slave: The SPI slave
*
* Returns: 0 if the bus was claimed successfully, or a negative value
* if it wasn't.
*/
int spi_claim_bus(struct spi_slave *slave);
/*-----------------------------------------------------------------------
* Release the SPI bus
*
* This must be called once for every call to spi_claim_bus() after
* all transfers have finished. It may disable any SPI hardware as
* appropriate.
*
* slave: The SPI slave
*/
void spi_release_bus(struct spi_slave *slave);
/*-----------------------------------------------------------------------
* SPI transfer
*
* spi_xfer() interface:
* slave: The SPI slave which will be sending/receiving the data.
* dout: Pointer to a string of bytes to send out.
* bytesout: How many bytes to write.
* din: Pointer to a string of bytes that will be filled in.
* bytesin: How many bytes to read.
*
* Returns: 0 on success, not 0 on failure
*/
int spi_xfer(struct spi_slave *slave, const void *dout, unsigned int bytesout,
void *din, unsigned int bytesin);
/*-----------------------------------------------------------------------
* Determine if a SPI chipselect is valid.
* This function is provided by the board if the low-level SPI driver
* needs it to determine if a given chipselect is actually valid.
*
* Returns: 1 if bus:cs identifies a valid chip on this board, 0
* otherwise.
*/
int spi_cs_is_valid(unsigned int bus, unsigned int cs);
/*-----------------------------------------------------------------------
* Activate a SPI chipselect.
* This function is provided by the board code when using a driver
* that can't control its chipselects automatically (e.g.
* common/soft_spi.c). When called, it should activate the chip select
* to the device identified by "slave".
*/
void spi_cs_activate(struct spi_slave *slave);
/*-----------------------------------------------------------------------
* Deactivate a SPI chipselect.
* This function is provided by the board code when using a driver
* that can't control its chipselects automatically (e.g.
* common/soft_spi.c). When called, it should deactivate the chip
* select to the device identified by "slave".
*/
void spi_cs_deactivate(struct spi_slave *slave);
/*-----------------------------------------------------------------------
* Set transfer speed.
* This sets a new speed to be applied for next spi_xfer().
* slave: The SPI slave
* hz: The transfer speed
*/
void spi_set_speed(struct spi_slave *slave, uint32_t hz);
unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len);
/*-----------------------------------------------------------------------
* Write 8 bits, then read 8 bits.
* slave: The SPI slave we're communicating with
* byte: Byte to be written
*
* Returns: The value that was read, or a negative value on error.
*
* TODO: This function probably shouldn't be inlined.
*/
static inline int spi_w8r8(struct spi_slave *slave, unsigned char byte)
{
unsigned char dout[2];
unsigned char din[2];
int ret;
dout[0] = byte;
dout[1] = 0;
ret = spi_xfer(slave, dout, 2, din, 2);
return ret < 0 ? ret : din[1];
}
#endif /* _SPI_GENERIC_H_ */
|
