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77f85581 WD |
1 | /* |
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 | ||
f8cc312b BW |
27 | /* Controller-specific definitions: */ |
28 | ||
38254f45 GL |
29 | /* 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) | |
d255bb0e | 36 | #define SPI_CS_HIGH 0x04 /* CS active high */ |
38254f45 GL |
37 | #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 */ | |
bb786b84 RS |
40 | #define SPI_SLAVE 0x40 /* slave mode */ |
41 | #define SPI_PREAMBLE 0x80 /* Skip preamble bytes */ | |
38254f45 | 42 | |
d255bb0e HS |
43 | /* SPI transfer flags */ |
44 | #define SPI_XFER_BEGIN 0x01 /* Assert CS before transfer */ | |
45 | #define SPI_XFER_END 0x02 /* Deassert CS after transfer */ | |
77f85581 | 46 | |
bb786b84 RS |
47 | /* Header byte that marks the start of the message */ |
48 | #define SPI_PREAMBLE_END_BYTE 0xec | |
49 | ||
d255bb0e HS |
50 | /*----------------------------------------------------------------------- |
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. | |
0c456cee SG |
57 | * max_write_size: If non-zero, the maximum number of bytes which can |
58 | * be written at once, excluding command bytes. | |
d255bb0e HS |
59 | */ |
60 | struct spi_slave { | |
61 | unsigned int bus; | |
62 | unsigned int cs; | |
0c456cee | 63 | unsigned int max_write_size; |
d255bb0e | 64 | }; |
77f85581 WD |
65 | |
66 | /*----------------------------------------------------------------------- | |
67 | * Initialization, must be called once on start up. | |
d255bb0e HS |
68 | * |
69 | * TODO: I don't think we really need this. | |
77f85581 WD |
70 | */ |
71 | void spi_init(void); | |
72 | ||
ba6c3ce9 SG |
73 | /** |
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 | */ | |
84 | void *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 | ||
d255bb0e HS |
114 | /*----------------------------------------------------------------------- |
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 | */ | |
130 | struct 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 | */ | |
138 | void 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 | */ | |
154 | int 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 | */ | |
165 | void spi_release_bus(struct spi_slave *slave); | |
77f85581 WD |
166 | |
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 | * | |
77f85581 | 179 | * spi_xfer() interface: |
d255bb0e HS |
180 | * 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. | |
77f85581 WD |
186 | * |
187 | * Returns: 0 on success, not 0 on failure | |
188 | */ | |
d255bb0e HS |
189 | int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout, |
190 | void *din, unsigned long flags); | |
191 | ||
192 | /*----------------------------------------------------------------------- | |
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 | */ | |
200 | int 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 | */ | |
209 | void 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 | */ | |
218 | void spi_cs_deactivate(struct spi_slave *slave); | |
219 | ||
fa1423e7 TC |
220 | /*----------------------------------------------------------------------- |
221 | * 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 | */ | |
226 | void spi_set_speed(struct spi_slave *slave, uint hz); | |
227 | ||
d255bb0e HS |
228 | /*----------------------------------------------------------------------- |
229 | * 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 | */ | |
237 | static 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; | |
38254f45 | 245 | |
d255bb0e HS |
246 | ret = spi_xfer(slave, 16, dout, din, SPI_XFER_BEGIN | SPI_XFER_END); |
247 | return ret < 0 ? ret : din[1]; | |
248 | } | |
77f85581 | 249 | |
f3424c55 HT |
250 | /** |
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 | */ | |
263 | struct spi_slave *spi_setup_slave_fdt(const void *blob, int node, | |
264 | unsigned int cs, unsigned int max_hz, unsigned int mode); | |
265 | ||
77f85581 | 266 | #endif /* _SPI_H_ */ |