1 /* 2 * Common SPI Interface: Controller-specific definitions 3 * 4 * (C) Copyright 2001 5 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com. 6 * 7 * SPDX-License-Identifier: GPL-2.0+ 8 */ 9 10 #ifndef _SPI_H_ 11 #define _SPI_H_ 12 13 /* 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) 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 */ 26 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) 34 35 /* SPI TX operation modes */ 36 #define SPI_OPM_TX_QPP 1 << 0 37 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 | \ 46 SPI_OPM_RX_QIOF 47 48 /* SPI bus connection options */ 49 #define SPI_CONN_DUAL_SHARED 1 << 0 50 #define SPI_CONN_DUAL_SEPARATED 1 << 1 51 52 /* Header byte that marks the start of the message */ 53 #define SPI_PREAMBLE_END_BYTE 0xec 54 55 #define SPI_DEFAULT_WORDLEN 8 56 57 /** 58 * struct spi_slave - Representation of a SPI slave 59 * 60 * Drivers are expected to extend this with controller-specific data. 61 * 62 * @bus: ID of the bus that the slave is attached to. 63 * @cs: ID of the chip select connected to the slave. 64 * @op_mode_rx: SPI RX operation mode. 65 * @op_mode_tx: SPI TX operation mode. 66 * @wordlen: Size of SPI word in number of bits 67 * @max_write_size: If non-zero, the maximum number of bytes which can 68 * be written at once, excluding command bytes. 69 * @memory_map: Address of read-only SPI flash access. 70 * @option: Varies SPI bus options - separate, shared bus. 71 * @flags: Indication of SPI flags. 72 */ 73 struct spi_slave { 74 unsigned int bus; 75 unsigned int cs; 76 u8 op_mode_rx; 77 u8 op_mode_tx; 78 unsigned int wordlen; 79 unsigned int max_write_size; 80 void *memory_map; 81 u8 option; 82 u8 flags; 83 }; 84 85 /** 86 * Initialization, must be called once on start up. 87 * 88 * TODO: I don't think we really need this. 89 */ 90 void spi_init(void); 91 92 /** 93 * spi_do_alloc_slave - Allocate a new SPI slave (internal) 94 * 95 * Allocate and zero all fields in the spi slave, and set the bus/chip 96 * select. Use the helper macro spi_alloc_slave() to call this. 97 * 98 * @offset: Offset of struct spi_slave within slave structure. 99 * @size: Size of slave structure. 100 * @bus: Bus ID of the slave chip. 101 * @cs: Chip select ID of the slave chip on the specified bus. 102 */ 103 void *spi_do_alloc_slave(int offset, int size, unsigned int bus, 104 unsigned int cs); 105 106 /** 107 * spi_alloc_slave - Allocate a new SPI slave 108 * 109 * Allocate and zero all fields in the spi slave, and set the bus/chip 110 * select. 111 * 112 * @_struct: Name of structure to allocate (e.g. struct tegra_spi). 113 * This structure must contain a member 'struct spi_slave *slave'. 114 * @bus: Bus ID of the slave chip. 115 * @cs: Chip select ID of the slave chip on the specified bus. 116 */ 117 #define spi_alloc_slave(_struct, bus, cs) \ 118 spi_do_alloc_slave(offsetof(_struct, slave), \ 119 sizeof(_struct), bus, cs) 120 121 /** 122 * spi_alloc_slave_base - Allocate a new SPI slave with no private data 123 * 124 * Allocate and zero all fields in the spi slave, and set the bus/chip 125 * select. 126 * 127 * @bus: Bus ID of the slave chip. 128 * @cs: Chip select ID of the slave chip on the specified bus. 129 */ 130 #define spi_alloc_slave_base(bus, cs) \ 131 spi_do_alloc_slave(0, sizeof(struct spi_slave), bus, cs) 132 133 /** 134 * Set up communications parameters for a SPI slave. 135 * 136 * This must be called once for each slave. Note that this function 137 * usually doesn't touch any actual hardware, it only initializes the 138 * contents of spi_slave so that the hardware can be easily 139 * initialized later. 140 * 141 * @bus: Bus ID of the slave chip. 142 * @cs: Chip select ID of the slave chip on the specified bus. 143 * @max_hz: Maximum SCK rate in Hz. 144 * @mode: Clock polarity, clock phase and other parameters. 145 * 146 * Returns: A spi_slave reference that can be used in subsequent SPI 147 * calls, or NULL if one or more of the parameters are not supported. 148 */ 149 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, 150 unsigned int max_hz, unsigned int mode); 151 152 /** 153 * Free any memory associated with a SPI slave. 154 * 155 * @slave: The SPI slave 156 */ 157 void spi_free_slave(struct spi_slave *slave); 158 159 /** 160 * Claim the bus and prepare it for communication with a given slave. 161 * 162 * This must be called before doing any transfers with a SPI slave. It 163 * will enable and initialize any SPI hardware as necessary, and make 164 * sure that the SCK line is in the correct idle state. It is not 165 * allowed to claim the same bus for several slaves without releasing 166 * the bus in between. 167 * 168 * @slave: The SPI slave 169 * 170 * Returns: 0 if the bus was claimed successfully, or a negative value 171 * if it wasn't. 172 */ 173 int spi_claim_bus(struct spi_slave *slave); 174 175 /** 176 * Release the SPI bus 177 * 178 * This must be called once for every call to spi_claim_bus() after 179 * all transfers have finished. It may disable any SPI hardware as 180 * appropriate. 181 * 182 * @slave: The SPI slave 183 */ 184 void spi_release_bus(struct spi_slave *slave); 185 186 /** 187 * Set the word length for SPI transactions 188 * 189 * Set the word length (number of bits per word) for SPI transactions. 190 * 191 * @slave: The SPI slave 192 * @wordlen: The number of bits in a word 193 * 194 * Returns: 0 on success, -1 on failure. 195 */ 196 int spi_set_wordlen(struct spi_slave *slave, unsigned int wordlen); 197 198 /** 199 * SPI transfer 200 * 201 * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks 202 * "bitlen" bits in the SPI MISO port. That's just the way SPI works. 203 * 204 * The source of the outgoing bits is the "dout" parameter and the 205 * destination of the input bits is the "din" parameter. Note that "dout" 206 * and "din" can point to the same memory location, in which case the 207 * input data overwrites the output data (since both are buffered by 208 * temporary variables, this is OK). 209 * 210 * spi_xfer() interface: 211 * @slave: The SPI slave which will be sending/receiving the data. 212 * @bitlen: How many bits to write and read. 213 * @dout: Pointer to a string of bits to send out. The bits are 214 * held in a byte array and are sent MSB first. 215 * @din: Pointer to a string of bits that will be filled in. 216 * @flags: A bitwise combination of SPI_XFER_* flags. 217 * 218 * Returns: 0 on success, not 0 on failure 219 */ 220 int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout, 221 void *din, unsigned long flags); 222 223 /** 224 * Determine if a SPI chipselect is valid. 225 * This function is provided by the board if the low-level SPI driver 226 * needs it to determine if a given chipselect is actually valid. 227 * 228 * Returns: 1 if bus:cs identifies a valid chip on this board, 0 229 * otherwise. 230 */ 231 int spi_cs_is_valid(unsigned int bus, unsigned int cs); 232 233 /** 234 * Activate a SPI chipselect. 235 * This function is provided by the board code when using a driver 236 * that can't control its chipselects automatically (e.g. 237 * common/soft_spi.c). When called, it should activate the chip select 238 * to the device identified by "slave". 239 */ 240 void spi_cs_activate(struct spi_slave *slave); 241 242 /** 243 * Deactivate a SPI chipselect. 244 * This function is provided by the board code when using a driver 245 * that can't control its chipselects automatically (e.g. 246 * common/soft_spi.c). When called, it should deactivate the chip 247 * select to the device identified by "slave". 248 */ 249 void spi_cs_deactivate(struct spi_slave *slave); 250 251 /** 252 * Set transfer speed. 253 * This sets a new speed to be applied for next spi_xfer(). 254 * @slave: The SPI slave 255 * @hz: The transfer speed 256 */ 257 void spi_set_speed(struct spi_slave *slave, uint hz); 258 259 /** 260 * Write 8 bits, then read 8 bits. 261 * @slave: The SPI slave we're communicating with 262 * @byte: Byte to be written 263 * 264 * Returns: The value that was read, or a negative value on error. 265 * 266 * TODO: This function probably shouldn't be inlined. 267 */ 268 static inline int spi_w8r8(struct spi_slave *slave, unsigned char byte) 269 { 270 unsigned char dout[2]; 271 unsigned char din[2]; 272 int ret; 273 274 dout[0] = byte; 275 dout[1] = 0; 276 277 ret = spi_xfer(slave, 16, dout, din, SPI_XFER_BEGIN | SPI_XFER_END); 278 return ret < 0 ? ret : din[1]; 279 } 280 281 /** 282 * Set up a SPI slave for a particular device tree node 283 * 284 * This calls spi_setup_slave() with the correct bus number. Call 285 * spi_free_slave() to free it later. 286 * 287 * @param blob: Device tree blob 288 * @param slave_node: Slave node to use 289 * @param spi_node: SPI peripheral node to use 290 * @return pointer to new spi_slave structure 291 */ 292 struct spi_slave *spi_setup_slave_fdt(const void *blob, int slave_node, 293 int spi_node); 294 295 /** 296 * spi_base_setup_slave_fdt() - helper function to set up a SPI slace 297 * 298 * This decodes SPI properties from the slave node to determine the 299 * chip select and SPI parameters. 300 * 301 * @blob: Device tree blob 302 * @busnum: Bus number to use 303 * @node: Device tree node for the SPI bus 304 */ 305 struct spi_slave *spi_base_setup_slave_fdt(const void *blob, int busnum, 306 int node); 307 308 #endif /* _SPI_H_ */ 309