Stefan Reinauer | 1c56d9b | 2012-05-10 11:27:32 -0700 | [diff] [blame] | 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 | |
Patrick Georgi | bc64cae | 2013-02-11 22:12:55 +0100 | [diff] [blame] | 24 | #ifndef _SPI_GENERIC_H_ |
| 25 | #define _SPI_GENERIC_H_ |
Stefan Reinauer | 1c56d9b | 2012-05-10 11:27:32 -0700 | [diff] [blame] | 26 | |
| 27 | #include <stdint.h> |
| 28 | |
| 29 | /* Controller-specific definitions: */ |
| 30 | |
| 31 | /* SPI mode flags */ |
| 32 | #define SPI_CPHA 0x01 /* clock phase */ |
| 33 | #define SPI_CPOL 0x02 /* clock polarity */ |
| 34 | #define SPI_MODE_0 (0|0) /* (original MicroWire) */ |
| 35 | #define SPI_MODE_1 (0|SPI_CPHA) |
| 36 | #define SPI_MODE_2 (SPI_CPOL|0) |
| 37 | #define SPI_MODE_3 (SPI_CPOL|SPI_CPHA) |
| 38 | #define SPI_CS_HIGH 0x04 /* CS active high */ |
| 39 | #define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */ |
| 40 | #define SPI_3WIRE 0x10 /* SI/SO signals shared */ |
| 41 | #define SPI_LOOP 0x20 /* loopback mode */ |
| 42 | |
| 43 | /* SPI transfer flags */ |
| 44 | #define SPI_XFER_BEGIN 0x01 /* Assert CS before transfer */ |
| 45 | #define SPI_XFER_END 0x02 /* Deassert CS after transfer */ |
| 46 | |
Duncan Laurie | a2f1b95 | 2012-08-27 11:10:43 -0700 | [diff] [blame] | 47 | /* SPI opcodes */ |
| 48 | #define SPI_OPCODE_WREN 0x06 |
Duncan Laurie | 23b0053 | 2012-10-10 14:21:23 -0700 | [diff] [blame] | 49 | #define SPI_OPCODE_FAST_READ 0x0b |
Duncan Laurie | a2f1b95 | 2012-08-27 11:10:43 -0700 | [diff] [blame] | 50 | |
Martin Roth | 3316cf2 | 2012-12-05 16:22:54 -0700 | [diff] [blame] | 51 | #define SPI_READ_FLAG 0x01 |
| 52 | #define SPI_WRITE_FLAG 0x02 |
| 53 | |
Stefan Reinauer | 1c56d9b | 2012-05-10 11:27:32 -0700 | [diff] [blame] | 54 | /*----------------------------------------------------------------------- |
| 55 | * Representation of a SPI slave, i.e. what we're communicating with. |
| 56 | * |
| 57 | * Drivers are expected to extend this with controller-specific data. |
| 58 | * |
| 59 | * bus: ID of the bus that the slave is attached to. |
| 60 | * cs: ID of the chip select connected to the slave. |
Martin Roth | 3316cf2 | 2012-12-05 16:22:54 -0700 | [diff] [blame] | 61 | * rw: Read or Write flag |
Stefan Reinauer | 1c56d9b | 2012-05-10 11:27:32 -0700 | [diff] [blame] | 62 | */ |
| 63 | struct spi_slave { |
| 64 | unsigned int bus; |
| 65 | unsigned int cs; |
Martin Roth | 3316cf2 | 2012-12-05 16:22:54 -0700 | [diff] [blame] | 66 | unsigned int rw; |
Stefan Reinauer | 1c56d9b | 2012-05-10 11:27:32 -0700 | [diff] [blame] | 67 | }; |
| 68 | |
| 69 | /*----------------------------------------------------------------------- |
| 70 | * Initialization, must be called once on start up. |
| 71 | * |
Stefan Reinauer | 1c56d9b | 2012-05-10 11:27:32 -0700 | [diff] [blame] | 72 | */ |
| 73 | void spi_init(void); |
| 74 | |
| 75 | /*----------------------------------------------------------------------- |
| 76 | * Set up communications parameters for a SPI slave. |
| 77 | * |
| 78 | * This must be called once for each slave. Note that this function |
| 79 | * usually doesn't touch any actual hardware, it only initializes the |
| 80 | * contents of spi_slave so that the hardware can be easily |
| 81 | * initialized later. |
| 82 | * |
| 83 | * bus: Bus ID of the slave chip. |
| 84 | * cs: Chip select ID of the slave chip on the specified bus. |
| 85 | * max_hz: Maximum SCK rate in Hz. |
| 86 | * mode: Clock polarity, clock phase and other parameters. |
| 87 | * |
| 88 | * Returns: A spi_slave reference that can be used in subsequent SPI |
| 89 | * calls, or NULL if one or more of the parameters are not supported. |
| 90 | */ |
| 91 | struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, |
| 92 | unsigned int max_hz, unsigned int mode); |
| 93 | |
| 94 | /*----------------------------------------------------------------------- |
Stefan Reinauer | 1c56d9b | 2012-05-10 11:27:32 -0700 | [diff] [blame] | 95 | * Claim the bus and prepare it for communication with a given slave. |
| 96 | * |
| 97 | * This must be called before doing any transfers with a SPI slave. It |
| 98 | * will enable and initialize any SPI hardware as necessary, and make |
| 99 | * sure that the SCK line is in the correct idle state. It is not |
| 100 | * allowed to claim the same bus for several slaves without releasing |
| 101 | * the bus in between. |
| 102 | * |
| 103 | * slave: The SPI slave |
| 104 | * |
| 105 | * Returns: 0 if the bus was claimed successfully, or a negative value |
| 106 | * if it wasn't. |
| 107 | */ |
| 108 | int spi_claim_bus(struct spi_slave *slave); |
| 109 | |
| 110 | /*----------------------------------------------------------------------- |
| 111 | * Release the SPI bus |
| 112 | * |
| 113 | * This must be called once for every call to spi_claim_bus() after |
| 114 | * all transfers have finished. It may disable any SPI hardware as |
| 115 | * appropriate. |
| 116 | * |
| 117 | * slave: The SPI slave |
| 118 | */ |
| 119 | void spi_release_bus(struct spi_slave *slave); |
| 120 | |
| 121 | /*----------------------------------------------------------------------- |
| 122 | * SPI transfer |
| 123 | * |
| 124 | * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks |
| 125 | * "bitlen" bits in the SPI MISO port. That's just the way SPI works. |
| 126 | * |
| 127 | * The source of the outgoing bits is the "dout" parameter and the |
| 128 | * destination of the input bits is the "din" parameter. Note that "dout" |
| 129 | * and "din" can point to the same memory location, in which case the |
| 130 | * input data overwrites the output data (since both are buffered by |
| 131 | * temporary variables, this is OK). |
| 132 | * |
| 133 | * spi_xfer() interface: |
| 134 | * slave: The SPI slave which will be sending/receiving the data. |
| 135 | * dout: Pointer to a string of bits to send out. The bits are |
| 136 | * held in a byte array and are sent MSB first. |
| 137 | * bitsout: How many bits to write. |
| 138 | * din: Pointer to a string of bits that will be filled in. |
| 139 | * bitsin: How many bits to read. |
| 140 | * |
| 141 | * Returns: 0 on success, not 0 on failure |
| 142 | */ |
| 143 | int spi_xfer(struct spi_slave *slave, const void *dout, unsigned int bitsout, |
| 144 | void *din, unsigned int bitsin); |
| 145 | |
| 146 | /*----------------------------------------------------------------------- |
| 147 | * Determine if a SPI chipselect is valid. |
| 148 | * This function is provided by the board if the low-level SPI driver |
| 149 | * needs it to determine if a given chipselect is actually valid. |
| 150 | * |
| 151 | * Returns: 1 if bus:cs identifies a valid chip on this board, 0 |
| 152 | * otherwise. |
| 153 | */ |
| 154 | int spi_cs_is_valid(unsigned int bus, unsigned int cs); |
| 155 | |
| 156 | /*----------------------------------------------------------------------- |
| 157 | * Activate a SPI chipselect. |
| 158 | * This function is provided by the board code when using a driver |
| 159 | * that can't control its chipselects automatically (e.g. |
| 160 | * common/soft_spi.c). When called, it should activate the chip select |
| 161 | * to the device identified by "slave". |
| 162 | */ |
| 163 | void spi_cs_activate(struct spi_slave *slave); |
| 164 | |
| 165 | /*----------------------------------------------------------------------- |
| 166 | * Deactivate a SPI chipselect. |
| 167 | * This function is provided by the board code when using a driver |
| 168 | * that can't control its chipselects automatically (e.g. |
| 169 | * common/soft_spi.c). When called, it should deactivate the chip |
| 170 | * select to the device identified by "slave". |
| 171 | */ |
| 172 | void spi_cs_deactivate(struct spi_slave *slave); |
| 173 | |
| 174 | /*----------------------------------------------------------------------- |
| 175 | * Set transfer speed. |
| 176 | * This sets a new speed to be applied for next spi_xfer(). |
| 177 | * slave: The SPI slave |
| 178 | * hz: The transfer speed |
| 179 | */ |
| 180 | void spi_set_speed(struct spi_slave *slave, uint32_t hz); |
| 181 | |
| 182 | /*----------------------------------------------------------------------- |
| 183 | * Write 8 bits, then read 8 bits. |
| 184 | * slave: The SPI slave we're communicating with |
| 185 | * byte: Byte to be written |
| 186 | * |
| 187 | * Returns: The value that was read, or a negative value on error. |
| 188 | * |
| 189 | * TODO: This function probably shouldn't be inlined. |
| 190 | */ |
| 191 | static inline int spi_w8r8(struct spi_slave *slave, unsigned char byte) |
| 192 | { |
| 193 | unsigned char dout[2]; |
| 194 | unsigned char din[2]; |
| 195 | int ret; |
| 196 | |
| 197 | dout[0] = byte; |
| 198 | dout[1] = 0; |
| 199 | |
| 200 | ret = spi_xfer(slave, dout, 16, din, 16); |
| 201 | return ret < 0 ? ret : din[1]; |
| 202 | } |
| 203 | |
Patrick Georgi | bc64cae | 2013-02-11 22:12:55 +0100 | [diff] [blame] | 204 | #endif /* _SPI_GENERIC_H_ */ |