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wdenk77f85582002-09-26 02:01:47 +00001/*
Jagannadha Sutradharudu Teki469146c2013-10-10 22:14:09 +05302 * Common SPI Interface: Controller-specific definitions
3 *
wdenk77f85582002-09-26 02:01:47 +00004 * (C) Copyright 2001
5 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
6 *
Wolfgang Denk1a459662013-07-08 09:37:19 +02007 * SPDX-License-Identifier: GPL-2.0+
wdenk77f85582002-09-26 02:01:47 +00008 */
9
10#ifndef _SPI_H_
11#define _SPI_H_
12
Guennadi Liakhovetski38254f42008-04-15 14:14:25 +020013/* SPI mode flags */
14#define SPI_CPHA 0x01 /* clock phase */
15#define SPI_CPOL 0x02 /* clock polarity */
16#define SPI_MODE_0 (0|0) /* (original MicroWire) */
17#define SPI_MODE_1 (0|SPI_CPHA)
18#define SPI_MODE_2 (SPI_CPOL|0)
19#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
Haavard Skinnemoend255bb02008-05-16 11:10:31 +020020#define SPI_CS_HIGH 0x04 /* CS active high */
Guennadi Liakhovetski38254f42008-04-15 14:14:25 +020021#define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */
22#define SPI_3WIRE 0x10 /* SI/SO signals shared */
23#define SPI_LOOP 0x20 /* loopback mode */
Rajeshwari Shindebb786b82013-05-28 20:10:37 +000024#define SPI_SLAVE 0x40 /* slave mode */
25#define SPI_PREAMBLE 0x80 /* Skip preamble bytes */
Guennadi Liakhovetski38254f42008-04-15 14:14:25 +020026
Haavard Skinnemoend255bb02008-05-16 11:10:31 +020027/* SPI transfer flags */
Jagannadha Sutradharudu Tekice22b922013-10-07 19:34:56 +053028#define SPI_XFER_BEGIN 0x01 /* Assert CS before transfer */
29#define SPI_XFER_END 0x02 /* Deassert CS after transfer */
30#define SPI_XFER_MMAP 0x08 /* Memory Mapped start */
31#define SPI_XFER_MMAP_END 0x10 /* Memory Mapped End */
wdenk77f85582002-09-26 02:01:47 +000032
Rajeshwari Shindebb786b82013-05-28 20:10:37 +000033/* Header byte that marks the start of the message */
Jagannadha Sutradharudu Tekice22b922013-10-07 19:34:56 +053034#define SPI_PREAMBLE_END_BYTE 0xec
Rajeshwari Shindebb786b82013-05-28 20:10:37 +000035
Nikita Kiryanov5753d092013-10-16 17:23:25 +030036#define SPI_DEFAULT_WORDLEN 8
37
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +053038/**
Jagannadha Sutradharudu Tekice22b922013-10-07 19:34:56 +053039 * struct spi_slave - Representation of a SPI slave
Haavard Skinnemoend255bb02008-05-16 11:10:31 +020040 *
41 * Drivers are expected to extend this with controller-specific data.
42 *
Jagannadha Sutradharudu Tekice22b922013-10-07 19:34:56 +053043 * @bus: ID of the bus that the slave is attached to.
44 * @cs: ID of the chip select connected to the slave.
Nikita Kiryanov5753d092013-10-16 17:23:25 +030045 * @wordlen: Size of SPI word in number of bits
Jagannadha Sutradharudu Tekice22b922013-10-07 19:34:56 +053046 * @max_write_size: If non-zero, the maximum number of bytes which can
47 * be written at once, excluding command bytes.
48 * @memory_map: Address of read-only SPI flash access.
Haavard Skinnemoend255bb02008-05-16 11:10:31 +020049 */
50struct spi_slave {
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +053051 unsigned int bus;
52 unsigned int cs;
Nikita Kiryanov5753d092013-10-16 17:23:25 +030053 unsigned int wordlen;
Simon Glass0c456ce2013-03-11 06:08:05 +000054 unsigned int max_write_size;
Poddar, Sourav004f15b2013-10-07 15:53:01 +053055 void *memory_map;
Haavard Skinnemoend255bb02008-05-16 11:10:31 +020056};
wdenk77f85582002-09-26 02:01:47 +000057
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +053058/**
wdenk77f85582002-09-26 02:01:47 +000059 * Initialization, must be called once on start up.
Haavard Skinnemoend255bb02008-05-16 11:10:31 +020060 *
61 * TODO: I don't think we really need this.
wdenk77f85582002-09-26 02:01:47 +000062 */
63void spi_init(void);
64
Simon Glassba6c3ce2013-03-11 06:08:00 +000065/**
66 * spi_do_alloc_slave - Allocate a new SPI slave (internal)
67 *
68 * Allocate and zero all fields in the spi slave, and set the bus/chip
69 * select. Use the helper macro spi_alloc_slave() to call this.
70 *
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +053071 * @offset: Offset of struct spi_slave within slave structure.
72 * @size: Size of slave structure.
73 * @bus: Bus ID of the slave chip.
74 * @cs: Chip select ID of the slave chip on the specified bus.
Simon Glassba6c3ce2013-03-11 06:08:00 +000075 */
76void *spi_do_alloc_slave(int offset, int size, unsigned int bus,
77 unsigned int cs);
78
79/**
80 * spi_alloc_slave - Allocate a new SPI slave
81 *
82 * Allocate and zero all fields in the spi slave, and set the bus/chip
83 * select.
84 *
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +053085 * @_struct: Name of structure to allocate (e.g. struct tegra_spi).
86 * This structure must contain a member 'struct spi_slave *slave'.
87 * @bus: Bus ID of the slave chip.
88 * @cs: Chip select ID of the slave chip on the specified bus.
Simon Glassba6c3ce2013-03-11 06:08:00 +000089 */
90#define spi_alloc_slave(_struct, bus, cs) \
91 spi_do_alloc_slave(offsetof(_struct, slave), \
92 sizeof(_struct), bus, cs)
93
94/**
95 * spi_alloc_slave_base - Allocate a new SPI slave with no private data
96 *
97 * Allocate and zero all fields in the spi slave, and set the bus/chip
98 * select.
99 *
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530100 * @bus: Bus ID of the slave chip.
101 * @cs: Chip select ID of the slave chip on the specified bus.
Simon Glassba6c3ce2013-03-11 06:08:00 +0000102 */
103#define spi_alloc_slave_base(bus, cs) \
104 spi_do_alloc_slave(0, sizeof(struct spi_slave), bus, cs)
105
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530106/**
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200107 * Set up communications parameters for a SPI slave.
108 *
109 * This must be called once for each slave. Note that this function
110 * usually doesn't touch any actual hardware, it only initializes the
111 * contents of spi_slave so that the hardware can be easily
112 * initialized later.
113 *
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530114 * @bus: Bus ID of the slave chip.
115 * @cs: Chip select ID of the slave chip on the specified bus.
116 * @max_hz: Maximum SCK rate in Hz.
117 * @mode: Clock polarity, clock phase and other parameters.
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200118 *
119 * Returns: A spi_slave reference that can be used in subsequent SPI
120 * calls, or NULL if one or more of the parameters are not supported.
121 */
122struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
123 unsigned int max_hz, unsigned int mode);
124
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530125/**
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200126 * Free any memory associated with a SPI slave.
127 *
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530128 * @slave: The SPI slave
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200129 */
130void spi_free_slave(struct spi_slave *slave);
131
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530132/**
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200133 * Claim the bus and prepare it for communication with a given slave.
134 *
135 * This must be called before doing any transfers with a SPI slave. It
136 * will enable and initialize any SPI hardware as necessary, and make
137 * sure that the SCK line is in the correct idle state. It is not
138 * allowed to claim the same bus for several slaves without releasing
139 * the bus in between.
140 *
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530141 * @slave: The SPI slave
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200142 *
143 * Returns: 0 if the bus was claimed successfully, or a negative value
144 * if it wasn't.
145 */
146int spi_claim_bus(struct spi_slave *slave);
147
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530148/**
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200149 * Release the SPI bus
150 *
151 * This must be called once for every call to spi_claim_bus() after
152 * all transfers have finished. It may disable any SPI hardware as
153 * appropriate.
154 *
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530155 * @slave: The SPI slave
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200156 */
157void spi_release_bus(struct spi_slave *slave);
wdenk77f85582002-09-26 02:01:47 +0000158
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530159/**
Nikita Kiryanov5753d092013-10-16 17:23:25 +0300160 * Set the word length for SPI transactions
161 *
162 * Set the word length (number of bits per word) for SPI transactions.
163 *
164 * @slave: The SPI slave
165 * @wordlen: The number of bits in a word
166 *
167 * Returns: 0 on success, -1 on failure.
168 */
169int spi_set_wordlen(struct spi_slave *slave, unsigned int wordlen);
170
171/**
wdenk77f85582002-09-26 02:01:47 +0000172 * SPI transfer
173 *
174 * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks
175 * "bitlen" bits in the SPI MISO port. That's just the way SPI works.
176 *
177 * The source of the outgoing bits is the "dout" parameter and the
178 * destination of the input bits is the "din" parameter. Note that "dout"
179 * and "din" can point to the same memory location, in which case the
180 * input data overwrites the output data (since both are buffered by
181 * temporary variables, this is OK).
182 *
wdenk77f85582002-09-26 02:01:47 +0000183 * spi_xfer() interface:
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530184 * @slave: The SPI slave which will be sending/receiving the data.
185 * @bitlen: How many bits to write and read.
186 * @dout: Pointer to a string of bits to send out. The bits are
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200187 * held in a byte array and are sent MSB first.
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530188 * @din: Pointer to a string of bits that will be filled in.
189 * @flags: A bitwise combination of SPI_XFER_* flags.
wdenk77f85582002-09-26 02:01:47 +0000190 *
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530191 * Returns: 0 on success, not 0 on failure
wdenk77f85582002-09-26 02:01:47 +0000192 */
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200193int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
194 void *din, unsigned long flags);
Guennadi Liakhovetski38254f42008-04-15 14:14:25 +0200195
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530196/**
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200197 * Determine if a SPI chipselect is valid.
198 * This function is provided by the board if the low-level SPI driver
199 * needs it to determine if a given chipselect is actually valid.
200 *
201 * Returns: 1 if bus:cs identifies a valid chip on this board, 0
202 * otherwise.
203 */
204int spi_cs_is_valid(unsigned int bus, unsigned int cs);
205
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530206/**
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200207 * Activate 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 activate the chip select
211 * to the device identified by "slave".
212 */
213void spi_cs_activate(struct spi_slave *slave);
214
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530215/**
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200216 * Deactivate a SPI chipselect.
217 * This function is provided by the board code when using a driver
218 * that can't control its chipselects automatically (e.g.
219 * common/soft_spi.c). When called, it should deactivate the chip
220 * select to the device identified by "slave".
221 */
222void spi_cs_deactivate(struct spi_slave *slave);
223
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530224/**
Thomas Choufa1423e2010-12-24 15:16:07 +0800225 * Set transfer speed.
226 * This sets a new speed to be applied for next spi_xfer().
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530227 * @slave: The SPI slave
228 * @hz: The transfer speed
Thomas Choufa1423e2010-12-24 15:16:07 +0800229 */
230void spi_set_speed(struct spi_slave *slave, uint hz);
231
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530232/**
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200233 * Write 8 bits, then read 8 bits.
Jagannadha Sutradharudu Teki1b1bd9a2013-09-25 15:47:36 +0530234 * @slave: The SPI slave we're communicating with
235 * @byte: Byte to be written
Haavard Skinnemoend255bb02008-05-16 11:10:31 +0200236 *
237 * Returns: The value that was read, or a negative value on error.
238 *
239 * TODO: This function probably shouldn't be inlined.
240 */
241static inline int spi_w8r8(struct spi_slave *slave, unsigned char byte)
242{
243 unsigned char dout[2];
244 unsigned char din[2];
245 int ret;
246
247 dout[0] = byte;
248 dout[1] = 0;
249
250 ret = spi_xfer(slave, 16, dout, din, SPI_XFER_BEGIN | SPI_XFER_END);
251 return ret < 0 ? ret : din[1];
252}
wdenk77f85582002-09-26 02:01:47 +0000253
Hung-ying Tyanf3424c52013-05-15 18:27:30 +0800254/**
255 * Set up a SPI slave for a particular device tree node
256 *
257 * This calls spi_setup_slave() with the correct bus number. Call
258 * spi_free_slave() to free it later.
259 *
Jagannadha Sutradharudu Teki469146c2013-10-10 22:14:09 +0530260 * @param blob: Device tree blob
261 * @param node: SPI peripheral node to use
262 * @param cs: Chip select to use
263 * @param max_hz: Maximum SCK rate in Hz (0 for default)
264 * @param mode: Clock polarity, clock phase and other parameters
Hung-ying Tyanf3424c52013-05-15 18:27:30 +0800265 * @return pointer to new spi_slave structure
266 */
267struct spi_slave *spi_setup_slave_fdt(const void *blob, int node,
268 unsigned int cs, unsigned int max_hz, unsigned int mode);
269
wdenk77f85582002-09-26 02:01:47 +0000270#endif /* _SPI_H_ */