blob: 3fe2e1eab2defc568079cd8a035225bbf682b18d [file] [log] [blame]
wdenk77f85582002-09-26 02:01:47 +00001/*
2 * (C) Copyright 2001
3 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
4 *
5 * See file CREDITS for list of people who contributed to this
6 * project.
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of
11 * the License, or (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
21 * MA 02111-1307 USA
22 */
23
24#ifndef _SPI_H_
25#define _SPI_H_
26
Ben Warrenf8cc3122008-06-08 23:28:33 -070027/* Controller-specific definitions: */
28
Guennadi Liakhovetski38254f42008-04-15 14:14:25 +020029/* SPI mode flags */
30#define SPI_CPHA 0x01 /* clock phase */
31#define SPI_CPOL 0x02 /* clock polarity */
32#define SPI_MODE_0 (0|0) /* (original MicroWire) */
33#define SPI_MODE_1 (0|SPI_CPHA)
34#define SPI_MODE_2 (SPI_CPOL|0)
35#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
Haavard Skinnemoend255bb02008-05-16 11:10:31 +020036#define SPI_CS_HIGH 0x04 /* CS active high */
Guennadi Liakhovetski38254f42008-04-15 14:14:25 +020037#define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */
38#define SPI_3WIRE 0x10 /* SI/SO signals shared */
39#define SPI_LOOP 0x20 /* loopback mode */
40
Haavard Skinnemoend255bb02008-05-16 11:10:31 +020041/* SPI transfer flags */
42#define SPI_XFER_BEGIN 0x01 /* Assert CS before transfer */
43#define SPI_XFER_END 0x02 /* Deassert CS after transfer */
wdenk77f85582002-09-26 02:01:47 +000044
Haavard Skinnemoend255bb02008-05-16 11:10:31 +020045/*-----------------------------------------------------------------------
46 * Representation of a SPI slave, i.e. what we're communicating with.
47 *
48 * Drivers are expected to extend this with controller-specific data.
49 *
50 * bus: ID of the bus that the slave is attached to.
51 * cs: ID of the chip select connected to the slave.
Simon Glass0c456ce2013-03-11 06:08:05 +000052 * max_write_size: If non-zero, the maximum number of bytes which can
53 * be written at once, excluding command bytes.
Haavard Skinnemoend255bb02008-05-16 11:10:31 +020054 */
55struct spi_slave {
56 unsigned int bus;
57 unsigned int cs;
Simon Glass0c456ce2013-03-11 06:08:05 +000058 unsigned int max_write_size;
Haavard Skinnemoend255bb02008-05-16 11:10:31 +020059};
wdenk77f85582002-09-26 02:01:47 +000060
61/*-----------------------------------------------------------------------
62 * Initialization, must be called once on start up.
Haavard Skinnemoend255bb02008-05-16 11:10:31 +020063 *
64 * TODO: I don't think we really need this.
wdenk77f85582002-09-26 02:01:47 +000065 */
66void spi_init(void);
67
Simon Glassba6c3ce2013-03-11 06:08:00 +000068/**
69 * spi_do_alloc_slave - Allocate a new SPI slave (internal)
70 *
71 * Allocate and zero all fields in the spi slave, and set the bus/chip
72 * select. Use the helper macro spi_alloc_slave() to call this.
73 *
74 * @offset: Offset of struct spi_slave within slave structure
75 * @size: Size of slave structure
76 * @bus: Bus ID of the slave chip.
77 * @cs: Chip select ID of the slave chip on the specified bus.
78 */
79void *spi_do_alloc_slave(int offset, int size, unsigned int bus,
80 unsigned int cs);
81
82/**
83 * spi_alloc_slave - Allocate a new SPI slave
84 *
85 * Allocate and zero all fields in the spi slave, and set the bus/chip
86 * select.
87 *
88 * @_struct: Name of structure to allocate (e.g. struct tegra_spi). This
89 * structure must contain a member 'struct spi_slave *slave'.
90 * @bus: Bus ID of the slave chip.
91 * @cs: Chip select ID of the slave chip on the specified bus.
92 */
93#define spi_alloc_slave(_struct, bus, cs) \
94 spi_do_alloc_slave(offsetof(_struct, slave), \
95 sizeof(_struct), bus, cs)
96
97/**
98 * spi_alloc_slave_base - Allocate a new SPI slave with no private data
99 *
100 * Allocate and zero all fields in the spi slave, and set the bus/chip
101 * select.
102 *
103 * @bus: Bus ID of the slave chip.
104 * @cs: Chip select ID of the slave chip on the specified bus.
105 */
106#define spi_alloc_slave_base(bus, cs) \
107 spi_do_alloc_slave(0, sizeof(struct spi_slave), bus, cs)
108
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200109/*-----------------------------------------------------------------------
110 * Set up communications parameters for a SPI slave.
111 *
112 * This must be called once for each slave. Note that this function
113 * usually doesn't touch any actual hardware, it only initializes the
114 * contents of spi_slave so that the hardware can be easily
115 * initialized later.
116 *
117 * bus: Bus ID of the slave chip.
118 * cs: Chip select ID of the slave chip on the specified bus.
119 * max_hz: Maximum SCK rate in Hz.
120 * mode: Clock polarity, clock phase and other parameters.
121 *
122 * Returns: A spi_slave reference that can be used in subsequent SPI
123 * calls, or NULL if one or more of the parameters are not supported.
124 */
125struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
126 unsigned int max_hz, unsigned int mode);
127
128/*-----------------------------------------------------------------------
129 * Free any memory associated with a SPI slave.
130 *
131 * slave: The SPI slave
132 */
133void spi_free_slave(struct spi_slave *slave);
134
135/*-----------------------------------------------------------------------
136 * Claim the bus and prepare it for communication with a given slave.
137 *
138 * This must be called before doing any transfers with a SPI slave. It
139 * will enable and initialize any SPI hardware as necessary, and make
140 * sure that the SCK line is in the correct idle state. It is not
141 * allowed to claim the same bus for several slaves without releasing
142 * the bus in between.
143 *
144 * slave: The SPI slave
145 *
146 * Returns: 0 if the bus was claimed successfully, or a negative value
147 * if it wasn't.
148 */
149int spi_claim_bus(struct spi_slave *slave);
150
151/*-----------------------------------------------------------------------
152 * Release the SPI bus
153 *
154 * This must be called once for every call to spi_claim_bus() after
155 * all transfers have finished. It may disable any SPI hardware as
156 * appropriate.
157 *
158 * slave: The SPI slave
159 */
160void spi_release_bus(struct spi_slave *slave);
wdenk77f85582002-09-26 02:01:47 +0000161
162/*-----------------------------------------------------------------------
163 * SPI transfer
164 *
165 * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks
166 * "bitlen" bits in the SPI MISO port. That's just the way SPI works.
167 *
168 * The source of the outgoing bits is the "dout" parameter and the
169 * destination of the input bits is the "din" parameter. Note that "dout"
170 * and "din" can point to the same memory location, in which case the
171 * input data overwrites the output data (since both are buffered by
172 * temporary variables, this is OK).
173 *
wdenk77f85582002-09-26 02:01:47 +0000174 * spi_xfer() interface:
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200175 * slave: The SPI slave which will be sending/receiving the data.
176 * bitlen: How many bits to write and read.
177 * dout: Pointer to a string of bits to send out. The bits are
178 * held in a byte array and are sent MSB first.
179 * din: Pointer to a string of bits that will be filled in.
180 * flags: A bitwise combination of SPI_XFER_* flags.
wdenk77f85582002-09-26 02:01:47 +0000181 *
182 * Returns: 0 on success, not 0 on failure
183 */
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200184int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
185 void *din, unsigned long flags);
Guennadi Liakhovetski38254f42008-04-15 14:14:25 +0200186
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200187/*-----------------------------------------------------------------------
188 * Determine if a SPI chipselect is valid.
189 * This function is provided by the board if the low-level SPI driver
190 * needs it to determine if a given chipselect is actually valid.
191 *
192 * Returns: 1 if bus:cs identifies a valid chip on this board, 0
193 * otherwise.
194 */
195int spi_cs_is_valid(unsigned int bus, unsigned int cs);
196
197/*-----------------------------------------------------------------------
198 * Activate a SPI chipselect.
199 * This function is provided by the board code when using a driver
200 * that can't control its chipselects automatically (e.g.
201 * common/soft_spi.c). When called, it should activate the chip select
202 * to the device identified by "slave".
203 */
204void spi_cs_activate(struct spi_slave *slave);
205
206/*-----------------------------------------------------------------------
207 * Deactivate a SPI chipselect.
208 * This function is provided by the board code when using a driver
209 * that can't control its chipselects automatically (e.g.
210 * common/soft_spi.c). When called, it should deactivate the chip
211 * select to the device identified by "slave".
212 */
213void spi_cs_deactivate(struct spi_slave *slave);
214
215/*-----------------------------------------------------------------------
Thomas Choufa1423e2010-12-24 15:16:07 +0800216 * Set transfer speed.
217 * This sets a new speed to be applied for next spi_xfer().
218 * slave: The SPI slave
219 * hz: The transfer speed
220 */
221void spi_set_speed(struct spi_slave *slave, uint hz);
222
223/*-----------------------------------------------------------------------
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200224 * Write 8 bits, then read 8 bits.
225 * slave: The SPI slave we're communicating with
226 * byte: Byte to be written
227 *
228 * Returns: The value that was read, or a negative value on error.
229 *
230 * TODO: This function probably shouldn't be inlined.
231 */
232static inline int spi_w8r8(struct spi_slave *slave, unsigned char byte)
233{
234 unsigned char dout[2];
235 unsigned char din[2];
236 int ret;
237
238 dout[0] = byte;
239 dout[1] = 0;
240
241 ret = spi_xfer(slave, 16, dout, din, SPI_XFER_BEGIN | SPI_XFER_END);
242 return ret < 0 ? ret : din[1];
243}
wdenk77f85582002-09-26 02:01:47 +0000244
245#endif /* _SPI_H_ */