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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 */
Rajeshwari Shindebb786b82013-05-28 20:10:37 +000040#define SPI_SLAVE 0x40 /* slave mode */
41#define SPI_PREAMBLE 0x80 /* Skip preamble bytes */
Guennadi Liakhovetski38254f42008-04-15 14:14:25 +020042
Haavard Skinnemoend255bb02008-05-16 11:10:31 +020043/* SPI transfer flags */
44#define SPI_XFER_BEGIN 0x01 /* Assert CS before transfer */
45#define SPI_XFER_END 0x02 /* Deassert CS after transfer */
wdenk77f85582002-09-26 02:01:47 +000046
Rajeshwari Shindebb786b82013-05-28 20:10:37 +000047/* Header byte that marks the start of the message */
48#define SPI_PREAMBLE_END_BYTE 0xec
49
Haavard Skinnemoend255bb02008-05-16 11:10:31 +020050/*-----------------------------------------------------------------------
51 * Representation of a SPI slave, i.e. what we're communicating with.
52 *
53 * Drivers are expected to extend this with controller-specific data.
54 *
55 * bus: ID of the bus that the slave is attached to.
56 * cs: ID of the chip select connected to the slave.
Simon Glass0c456ce2013-03-11 06:08:05 +000057 * max_write_size: If non-zero, the maximum number of bytes which can
58 * be written at once, excluding command bytes.
Haavard Skinnemoend255bb02008-05-16 11:10:31 +020059 */
60struct spi_slave {
61 unsigned int bus;
62 unsigned int cs;
Simon Glass0c456ce2013-03-11 06:08:05 +000063 unsigned int max_write_size;
Haavard Skinnemoend255bb02008-05-16 11:10:31 +020064};
wdenk77f85582002-09-26 02:01:47 +000065
66/*-----------------------------------------------------------------------
67 * Initialization, must be called once on start up.
Haavard Skinnemoend255bb02008-05-16 11:10:31 +020068 *
69 * TODO: I don't think we really need this.
wdenk77f85582002-09-26 02:01:47 +000070 */
71void spi_init(void);
72
Simon Glassba6c3ce2013-03-11 06:08:00 +000073/**
74 * spi_do_alloc_slave - Allocate a new SPI slave (internal)
75 *
76 * Allocate and zero all fields in the spi slave, and set the bus/chip
77 * select. Use the helper macro spi_alloc_slave() to call this.
78 *
79 * @offset: Offset of struct spi_slave within slave structure
80 * @size: Size of slave structure
81 * @bus: Bus ID of the slave chip.
82 * @cs: Chip select ID of the slave chip on the specified bus.
83 */
84void *spi_do_alloc_slave(int offset, int size, unsigned int bus,
85 unsigned int cs);
86
87/**
88 * spi_alloc_slave - Allocate a new SPI slave
89 *
90 * Allocate and zero all fields in the spi slave, and set the bus/chip
91 * select.
92 *
93 * @_struct: Name of structure to allocate (e.g. struct tegra_spi). This
94 * structure must contain a member 'struct spi_slave *slave'.
95 * @bus: Bus ID of the slave chip.
96 * @cs: Chip select ID of the slave chip on the specified bus.
97 */
98#define spi_alloc_slave(_struct, bus, cs) \
99 spi_do_alloc_slave(offsetof(_struct, slave), \
100 sizeof(_struct), bus, cs)
101
102/**
103 * spi_alloc_slave_base - Allocate a new SPI slave with no private data
104 *
105 * Allocate and zero all fields in the spi slave, and set the bus/chip
106 * select.
107 *
108 * @bus: Bus ID of the slave chip.
109 * @cs: Chip select ID of the slave chip on the specified bus.
110 */
111#define spi_alloc_slave_base(bus, cs) \
112 spi_do_alloc_slave(0, sizeof(struct spi_slave), bus, cs)
113
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200114/*-----------------------------------------------------------------------
115 * Set up communications parameters for a SPI slave.
116 *
117 * This must be called once for each slave. Note that this function
118 * usually doesn't touch any actual hardware, it only initializes the
119 * contents of spi_slave so that the hardware can be easily
120 * initialized later.
121 *
122 * bus: Bus ID of the slave chip.
123 * cs: Chip select ID of the slave chip on the specified bus.
124 * max_hz: Maximum SCK rate in Hz.
125 * mode: Clock polarity, clock phase and other parameters.
126 *
127 * Returns: A spi_slave reference that can be used in subsequent SPI
128 * calls, or NULL if one or more of the parameters are not supported.
129 */
130struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
131 unsigned int max_hz, unsigned int mode);
132
133/*-----------------------------------------------------------------------
134 * Free any memory associated with a SPI slave.
135 *
136 * slave: The SPI slave
137 */
138void spi_free_slave(struct spi_slave *slave);
139
140/*-----------------------------------------------------------------------
141 * Claim the bus and prepare it for communication with a given slave.
142 *
143 * This must be called before doing any transfers with a SPI slave. It
144 * will enable and initialize any SPI hardware as necessary, and make
145 * sure that the SCK line is in the correct idle state. It is not
146 * allowed to claim the same bus for several slaves without releasing
147 * the bus in between.
148 *
149 * slave: The SPI slave
150 *
151 * Returns: 0 if the bus was claimed successfully, or a negative value
152 * if it wasn't.
153 */
154int spi_claim_bus(struct spi_slave *slave);
155
156/*-----------------------------------------------------------------------
157 * Release the SPI bus
158 *
159 * This must be called once for every call to spi_claim_bus() after
160 * all transfers have finished. It may disable any SPI hardware as
161 * appropriate.
162 *
163 * slave: The SPI slave
164 */
165void spi_release_bus(struct spi_slave *slave);
wdenk77f85582002-09-26 02:01:47 +0000166
167/*-----------------------------------------------------------------------
168 * SPI transfer
169 *
170 * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks
171 * "bitlen" bits in the SPI MISO port. That's just the way SPI works.
172 *
173 * The source of the outgoing bits is the "dout" parameter and the
174 * destination of the input bits is the "din" parameter. Note that "dout"
175 * and "din" can point to the same memory location, in which case the
176 * input data overwrites the output data (since both are buffered by
177 * temporary variables, this is OK).
178 *
wdenk77f85582002-09-26 02:01:47 +0000179 * spi_xfer() interface:
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200180 * slave: The SPI slave which will be sending/receiving the data.
181 * bitlen: How many bits to write and read.
182 * dout: Pointer to a string of bits to send out. The bits are
183 * held in a byte array and are sent MSB first.
184 * din: Pointer to a string of bits that will be filled in.
185 * flags: A bitwise combination of SPI_XFER_* flags.
wdenk77f85582002-09-26 02:01:47 +0000186 *
187 * Returns: 0 on success, not 0 on failure
188 */
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200189int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
190 void *din, unsigned long flags);
Guennadi Liakhovetski38254f42008-04-15 14:14:25 +0200191
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200192/*-----------------------------------------------------------------------
193 * Determine if a SPI chipselect is valid.
194 * This function is provided by the board if the low-level SPI driver
195 * needs it to determine if a given chipselect is actually valid.
196 *
197 * Returns: 1 if bus:cs identifies a valid chip on this board, 0
198 * otherwise.
199 */
200int spi_cs_is_valid(unsigned int bus, unsigned int cs);
201
202/*-----------------------------------------------------------------------
203 * Activate a SPI chipselect.
204 * This function is provided by the board code when using a driver
205 * that can't control its chipselects automatically (e.g.
206 * common/soft_spi.c). When called, it should activate the chip select
207 * to the device identified by "slave".
208 */
209void spi_cs_activate(struct spi_slave *slave);
210
211/*-----------------------------------------------------------------------
212 * Deactivate a SPI chipselect.
213 * This function is provided by the board code when using a driver
214 * that can't control its chipselects automatically (e.g.
215 * common/soft_spi.c). When called, it should deactivate the chip
216 * select to the device identified by "slave".
217 */
218void spi_cs_deactivate(struct spi_slave *slave);
219
220/*-----------------------------------------------------------------------
Thomas Choufa1423e2010-12-24 15:16:07 +0800221 * Set transfer speed.
222 * This sets a new speed to be applied for next spi_xfer().
223 * slave: The SPI slave
224 * hz: The transfer speed
225 */
226void spi_set_speed(struct spi_slave *slave, uint hz);
227
228/*-----------------------------------------------------------------------
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200229 * Write 8 bits, then read 8 bits.
230 * slave: The SPI slave we're communicating with
231 * byte: Byte to be written
232 *
233 * Returns: The value that was read, or a negative value on error.
234 *
235 * TODO: This function probably shouldn't be inlined.
236 */
237static inline int spi_w8r8(struct spi_slave *slave, unsigned char byte)
238{
239 unsigned char dout[2];
240 unsigned char din[2];
241 int ret;
242
243 dout[0] = byte;
244 dout[1] = 0;
245
246 ret = spi_xfer(slave, 16, dout, din, SPI_XFER_BEGIN | SPI_XFER_END);
247 return ret < 0 ? ret : din[1];
248}
wdenk77f85582002-09-26 02:01:47 +0000249
Hung-ying Tyanf3424c52013-05-15 18:27:30 +0800250/**
251 * Set up a SPI slave for a particular device tree node
252 *
253 * This calls spi_setup_slave() with the correct bus number. Call
254 * spi_free_slave() to free it later.
255 *
256 * @param blob Device tree blob
257 * @param node SPI peripheral node to use
258 * @param cs Chip select to use
259 * @param max_hz Maximum SCK rate in Hz (0 for default)
260 * @param mode Clock polarity, clock phase and other parameters
261 * @return pointer to new spi_slave structure
262 */
263struct spi_slave *spi_setup_slave_fdt(const void *blob, int node,
264 unsigned int cs, unsigned int max_hz, unsigned int mode);
265
wdenk77f85582002-09-26 02:01:47 +0000266#endif /* _SPI_H_ */