2 * Common SPI Interface: Controller-specific definitions
5 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
7 * SPDX-License-Identifier: GPL-2.0+
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)
20 #define SPI_CS_HIGH 0x04 /* CS active high */
21 #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 */
24 #define SPI_SLAVE 0x40 /* slave mode */
25 #define SPI_PREAMBLE 0x80 /* Skip preamble bytes */
27 /* SPI transfer flags */
28 #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 */
32 #define SPI_XFER_ONCE (SPI_XFER_BEGIN | SPI_XFER_END)
33 #define SPI_XFER_U_PAGE (1 << 5)
35 /* SPI TX operation modes */
36 #define SPI_OPM_TX_QPP 1 << 0
38 /* SPI RX operation modes */
39 #define SPI_OPM_RX_AS 1 << 0
40 #define SPI_OPM_RX_DOUT 1 << 1
41 #define SPI_OPM_RX_DIO 1 << 2
42 #define SPI_OPM_RX_QOF 1 << 3
43 #define SPI_OPM_RX_QIOF 1 << 4
44 #define SPI_OPM_RX_EXTN SPI_OPM_RX_AS | SPI_OPM_RX_DOUT | \
45 SPI_OPM_RX_DIO | SPI_OPM_RX_QOF | \
48 /* SPI bus connection options */
49 #define SPI_CONN_DUAL_SHARED 1 << 0
51 /* Header byte that marks the start of the message */
52 #define SPI_PREAMBLE_END_BYTE 0xec
54 #define SPI_DEFAULT_WORDLEN 8
57 * struct spi_slave - Representation of a SPI slave
59 * Drivers are expected to extend this with controller-specific data.
61 * @bus: ID of the bus that the slave is attached to.
62 * @cs: ID of the chip select connected to the slave.
63 * @op_mode_rx: SPI RX operation mode.
64 * @op_mode_tx: SPI TX operation mode.
65 * @wordlen: Size of SPI word in number of bits
66 * @max_write_size: If non-zero, the maximum number of bytes which can
67 * be written at once, excluding command bytes.
68 * @memory_map: Address of read-only SPI flash access.
69 * @option: Varies SPI bus options - separate bus.
70 * @flags: Indication of SPI flags.
78 unsigned int max_write_size;
85 * Initialization, must be called once on start up.
87 * TODO: I don't think we really need this.
92 * spi_do_alloc_slave - Allocate a new SPI slave (internal)
94 * Allocate and zero all fields in the spi slave, and set the bus/chip
95 * select. Use the helper macro spi_alloc_slave() to call this.
97 * @offset: Offset of struct spi_slave within slave structure.
98 * @size: Size of slave structure.
99 * @bus: Bus ID of the slave chip.
100 * @cs: Chip select ID of the slave chip on the specified bus.
102 void *spi_do_alloc_slave(int offset, int size, unsigned int bus,
106 * spi_alloc_slave - Allocate a new SPI slave
108 * Allocate and zero all fields in the spi slave, and set the bus/chip
111 * @_struct: Name of structure to allocate (e.g. struct tegra_spi).
112 * This structure must contain a member 'struct spi_slave *slave'.
113 * @bus: Bus ID of the slave chip.
114 * @cs: Chip select ID of the slave chip on the specified bus.
116 #define spi_alloc_slave(_struct, bus, cs) \
117 spi_do_alloc_slave(offsetof(_struct, slave), \
118 sizeof(_struct), bus, cs)
121 * spi_alloc_slave_base - Allocate a new SPI slave with no private data
123 * Allocate and zero all fields in the spi slave, and set the bus/chip
126 * @bus: Bus ID of the slave chip.
127 * @cs: Chip select ID of the slave chip on the specified bus.
129 #define spi_alloc_slave_base(bus, cs) \
130 spi_do_alloc_slave(0, sizeof(struct spi_slave), bus, cs)
133 * Set up communications parameters for a SPI slave.
135 * This must be called once for each slave. Note that this function
136 * usually doesn't touch any actual hardware, it only initializes the
137 * contents of spi_slave so that the hardware can be easily
140 * @bus: Bus ID of the slave chip.
141 * @cs: Chip select ID of the slave chip on the specified bus.
142 * @max_hz: Maximum SCK rate in Hz.
143 * @mode: Clock polarity, clock phase and other parameters.
145 * Returns: A spi_slave reference that can be used in subsequent SPI
146 * calls, or NULL if one or more of the parameters are not supported.
148 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
149 unsigned int max_hz, unsigned int mode);
152 * Free any memory associated with a SPI slave.
154 * @slave: The SPI slave
156 void spi_free_slave(struct spi_slave *slave);
159 * Claim the bus and prepare it for communication with a given slave.
161 * This must be called before doing any transfers with a SPI slave. It
162 * will enable and initialize any SPI hardware as necessary, and make
163 * sure that the SCK line is in the correct idle state. It is not
164 * allowed to claim the same bus for several slaves without releasing
165 * the bus in between.
167 * @slave: The SPI slave
169 * Returns: 0 if the bus was claimed successfully, or a negative value
172 int spi_claim_bus(struct spi_slave *slave);
175 * Release the SPI bus
177 * This must be called once for every call to spi_claim_bus() after
178 * all transfers have finished. It may disable any SPI hardware as
181 * @slave: The SPI slave
183 void spi_release_bus(struct spi_slave *slave);
186 * Set the word length for SPI transactions
188 * Set the word length (number of bits per word) for SPI transactions.
190 * @slave: The SPI slave
191 * @wordlen: The number of bits in a word
193 * Returns: 0 on success, -1 on failure.
195 int spi_set_wordlen(struct spi_slave *slave, unsigned int wordlen);
200 * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks
201 * "bitlen" bits in the SPI MISO port. That's just the way SPI works.
203 * The source of the outgoing bits is the "dout" parameter and the
204 * destination of the input bits is the "din" parameter. Note that "dout"
205 * and "din" can point to the same memory location, in which case the
206 * input data overwrites the output data (since both are buffered by
207 * temporary variables, this is OK).
209 * spi_xfer() interface:
210 * @slave: The SPI slave which will be sending/receiving the data.
211 * @bitlen: How many bits to write and read.
212 * @dout: Pointer to a string of bits to send out. The bits are
213 * held in a byte array and are sent MSB first.
214 * @din: Pointer to a string of bits that will be filled in.
215 * @flags: A bitwise combination of SPI_XFER_* flags.
217 * Returns: 0 on success, not 0 on failure
219 int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
220 void *din, unsigned long flags);
223 * Determine if a SPI chipselect is valid.
224 * This function is provided by the board if the low-level SPI driver
225 * needs it to determine if a given chipselect is actually valid.
227 * Returns: 1 if bus:cs identifies a valid chip on this board, 0
230 int spi_cs_is_valid(unsigned int bus, unsigned int cs);
233 * Activate a SPI chipselect.
234 * This function is provided by the board code when using a driver
235 * that can't control its chipselects automatically (e.g.
236 * common/soft_spi.c). When called, it should activate the chip select
237 * to the device identified by "slave".
239 void spi_cs_activate(struct spi_slave *slave);
242 * Deactivate a SPI chipselect.
243 * This function is provided by the board code when using a driver
244 * that can't control its chipselects automatically (e.g.
245 * common/soft_spi.c). When called, it should deactivate the chip
246 * select to the device identified by "slave".
248 void spi_cs_deactivate(struct spi_slave *slave);
251 * Set transfer speed.
252 * This sets a new speed to be applied for next spi_xfer().
253 * @slave: The SPI slave
254 * @hz: The transfer speed
256 void spi_set_speed(struct spi_slave *slave, uint hz);
259 * Write 8 bits, then read 8 bits.
260 * @slave: The SPI slave we're communicating with
261 * @byte: Byte to be written
263 * Returns: The value that was read, or a negative value on error.
265 * TODO: This function probably shouldn't be inlined.
267 static inline int spi_w8r8(struct spi_slave *slave, unsigned char byte)
269 unsigned char dout[2];
270 unsigned char din[2];
276 ret = spi_xfer(slave, 16, dout, din, SPI_XFER_BEGIN | SPI_XFER_END);
277 return ret < 0 ? ret : din[1];
281 * Set up a SPI slave for a particular device tree node
283 * This calls spi_setup_slave() with the correct bus number. Call
284 * spi_free_slave() to free it later.
286 * @param blob: Device tree blob
287 * @param slave_node: Slave node to use
288 * @param spi_node: SPI peripheral node to use
289 * @return pointer to new spi_slave structure
291 struct spi_slave *spi_setup_slave_fdt(const void *blob, int slave_node,
295 * spi_base_setup_slave_fdt() - helper function to set up a SPI slace
297 * This decodes SPI properties from the slave node to determine the
298 * chip select and SPI parameters.
300 * @blob: Device tree blob
301 * @busnum: Bus number to use
302 * @node: Device tree node for the SPI bus
304 struct spi_slave *spi_base_setup_slave_fdt(const void *blob, int busnum,