David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2005 David Brownell |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License as published by |
| 6 | * the Free Software Foundation; either version 2 of the License, or |
| 7 | * (at your option) any later version. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with this program; if not, write to the Free Software |
| 16 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 17 | */ |
| 18 | |
| 19 | #ifndef __LINUX_SPI_H |
| 20 | #define __LINUX_SPI_H |
| 21 | |
Randy Dunlap | 0a30c5c | 2009-01-04 12:00:47 -0800 | [diff] [blame] | 22 | #include <linux/device.h> |
Anton Vorontsov | 75368bf | 2009-09-22 16:46:04 -0700 | [diff] [blame] | 23 | #include <linux/mod_devicetable.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 24 | #include <linux/slab.h> |
Randy Dunlap | 0a30c5c | 2009-01-04 12:00:47 -0800 | [diff] [blame] | 25 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 26 | /* |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 27 | * INTERFACES between SPI master-side drivers and SPI infrastructure. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 28 | * (There's no SPI slave support for Linux yet...) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 29 | */ |
| 30 | extern struct bus_type spi_bus_type; |
| 31 | |
| 32 | /** |
| 33 | * struct spi_device - Master side proxy for an SPI slave device |
| 34 | * @dev: Driver model representation of the device. |
| 35 | * @master: SPI controller used with the device. |
| 36 | * @max_speed_hz: Maximum clock rate to be used with this chip |
| 37 | * (on this board); may be changed by the device's driver. |
Imre Deak | 4cff33f | 2006-02-17 10:02:18 -0800 | [diff] [blame] | 38 | * The spi_transfer.speed_hz can override this for each transfer. |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 39 | * @chip_select: Chipselect, distinguishing chips handled by @master. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 40 | * @mode: The spi mode defines how data is clocked out and in. |
| 41 | * This may be changed by the device's driver. |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 42 | * The "active low" default for chipselect mode can be overridden |
| 43 | * (by specifying SPI_CS_HIGH) as can the "MSB first" default for |
| 44 | * each word in a transfer (by specifying SPI_LSB_FIRST). |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 45 | * @bits_per_word: Data transfers involve one or more words; word sizes |
David Brownell | 747d844 | 2006-04-02 10:33:37 -0800 | [diff] [blame] | 46 | * like eight or 12 bits are common. In-memory wordsizes are |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 47 | * powers of two bytes (e.g. 20 bit samples use 32 bits). |
David Brownell | ccf77cc | 2006-04-03 15:46:22 -0700 | [diff] [blame] | 48 | * This may be changed by the device's driver, or left at the |
| 49 | * default (0) indicating protocol words are eight bit bytes. |
Imre Deak | 4cff33f | 2006-02-17 10:02:18 -0800 | [diff] [blame] | 50 | * The spi_transfer.bits_per_word can override this for each transfer. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 51 | * @irq: Negative, or the number passed to request_irq() to receive |
David Brownell | 747d844 | 2006-04-02 10:33:37 -0800 | [diff] [blame] | 52 | * interrupts from this device. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 53 | * @controller_state: Controller's runtime state |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 54 | * @controller_data: Board-specific definitions for controller, such as |
David Brownell | 747d844 | 2006-04-02 10:33:37 -0800 | [diff] [blame] | 55 | * FIFO initialization parameters; from board_info.controller_data |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 56 | * @modalias: Name of the driver to use with this device, or an alias |
| 57 | * for that name. This appears in the sysfs "modalias" attribute |
| 58 | * for driver coldplugging, and in uevents used for hotplugging |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 59 | * |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 60 | * A @spi_device is used to interchange data between an SPI slave |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 61 | * (usually a discrete chip) and CPU memory. |
| 62 | * |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 63 | * In @dev, the platform_data is used to hold information about this |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 64 | * device that's meaningful to the device's protocol driver, but not |
| 65 | * to its controller. One example might be an identifier for a chip |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 66 | * variant with slightly different functionality; another might be |
| 67 | * information about how this particular board wires the chip's pins. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 68 | */ |
| 69 | struct spi_device { |
| 70 | struct device dev; |
| 71 | struct spi_master *master; |
| 72 | u32 max_speed_hz; |
| 73 | u8 chip_select; |
| 74 | u8 mode; |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 75 | #define SPI_CPHA 0x01 /* clock phase */ |
| 76 | #define SPI_CPOL 0x02 /* clock polarity */ |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 77 | #define SPI_MODE_0 (0|0) /* (original MicroWire) */ |
| 78 | #define SPI_MODE_1 (0|SPI_CPHA) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 79 | #define SPI_MODE_2 (SPI_CPOL|0) |
| 80 | #define SPI_MODE_3 (SPI_CPOL|SPI_CPHA) |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 81 | #define SPI_CS_HIGH 0x04 /* chipselect active high? */ |
David Brownell | ccf77cc | 2006-04-03 15:46:22 -0700 | [diff] [blame] | 82 | #define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */ |
David Brownell | c06e677 | 2007-07-17 04:04:03 -0700 | [diff] [blame] | 83 | #define SPI_3WIRE 0x10 /* SI/SO signals shared */ |
Anton Vorontsov | 4ef7af5 | 2007-07-31 00:38:43 -0700 | [diff] [blame] | 84 | #define SPI_LOOP 0x20 /* loopback mode */ |
David Brownell | b55f627 | 2009-06-30 11:41:26 -0700 | [diff] [blame] | 85 | #define SPI_NO_CS 0x40 /* 1 dev/bus, no chipselect */ |
| 86 | #define SPI_READY 0x80 /* slave pulls low to pause */ |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 87 | u8 bits_per_word; |
| 88 | int irq; |
| 89 | void *controller_state; |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 90 | void *controller_data; |
Anton Vorontsov | 75368bf | 2009-09-22 16:46:04 -0700 | [diff] [blame] | 91 | char modalias[SPI_NAME_SIZE]; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 92 | |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 93 | /* |
| 94 | * likely need more hooks for more protocol options affecting how |
| 95 | * the controller talks to each chip, like: |
| 96 | * - memory packing (12 bit samples into low bits, others zeroed) |
| 97 | * - priority |
| 98 | * - drop chipselect after each word |
| 99 | * - chipselect delays |
| 100 | * - ... |
| 101 | */ |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 102 | }; |
| 103 | |
| 104 | static inline struct spi_device *to_spi_device(struct device *dev) |
| 105 | { |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 106 | return dev ? container_of(dev, struct spi_device, dev) : NULL; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 107 | } |
| 108 | |
| 109 | /* most drivers won't need to care about device refcounting */ |
| 110 | static inline struct spi_device *spi_dev_get(struct spi_device *spi) |
| 111 | { |
| 112 | return (spi && get_device(&spi->dev)) ? spi : NULL; |
| 113 | } |
| 114 | |
| 115 | static inline void spi_dev_put(struct spi_device *spi) |
| 116 | { |
| 117 | if (spi) |
| 118 | put_device(&spi->dev); |
| 119 | } |
| 120 | |
| 121 | /* ctldata is for the bus_master driver's runtime state */ |
| 122 | static inline void *spi_get_ctldata(struct spi_device *spi) |
| 123 | { |
| 124 | return spi->controller_state; |
| 125 | } |
| 126 | |
| 127 | static inline void spi_set_ctldata(struct spi_device *spi, void *state) |
| 128 | { |
| 129 | spi->controller_state = state; |
| 130 | } |
| 131 | |
Ben Dooks | 9b40ff4 | 2007-02-12 00:52:41 -0800 | [diff] [blame] | 132 | /* device driver data */ |
| 133 | |
| 134 | static inline void spi_set_drvdata(struct spi_device *spi, void *data) |
| 135 | { |
| 136 | dev_set_drvdata(&spi->dev, data); |
| 137 | } |
| 138 | |
| 139 | static inline void *spi_get_drvdata(struct spi_device *spi) |
| 140 | { |
| 141 | return dev_get_drvdata(&spi->dev); |
| 142 | } |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 143 | |
| 144 | struct spi_message; |
| 145 | |
| 146 | |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 147 | |
David Brownell | 2604288 | 2007-07-31 00:39:44 -0700 | [diff] [blame] | 148 | /** |
| 149 | * struct spi_driver - Host side "protocol" driver |
Anton Vorontsov | 75368bf | 2009-09-22 16:46:04 -0700 | [diff] [blame] | 150 | * @id_table: List of SPI devices supported by this driver |
David Brownell | 2604288 | 2007-07-31 00:39:44 -0700 | [diff] [blame] | 151 | * @probe: Binds this driver to the spi device. Drivers can verify |
| 152 | * that the device is actually present, and may need to configure |
| 153 | * characteristics (such as bits_per_word) which weren't needed for |
| 154 | * the initial configuration done during system setup. |
| 155 | * @remove: Unbinds this driver from the spi device |
| 156 | * @shutdown: Standard shutdown callback used during system state |
| 157 | * transitions such as powerdown/halt and kexec |
| 158 | * @suspend: Standard suspend callback used during system state transitions |
| 159 | * @resume: Standard resume callback used during system state transitions |
| 160 | * @driver: SPI device drivers should initialize the name and owner |
| 161 | * field of this structure. |
| 162 | * |
| 163 | * This represents the kind of device driver that uses SPI messages to |
| 164 | * interact with the hardware at the other end of a SPI link. It's called |
| 165 | * a "protocol" driver because it works through messages rather than talking |
| 166 | * directly to SPI hardware (which is what the underlying SPI controller |
| 167 | * driver does to pass those messages). These protocols are defined in the |
| 168 | * specification for the device(s) supported by the driver. |
| 169 | * |
| 170 | * As a rule, those device protocols represent the lowest level interface |
| 171 | * supported by a driver, and it will support upper level interfaces too. |
| 172 | * Examples of such upper levels include frameworks like MTD, networking, |
| 173 | * MMC, RTC, filesystem character device nodes, and hardware monitoring. |
| 174 | */ |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 175 | struct spi_driver { |
Anton Vorontsov | 75368bf | 2009-09-22 16:46:04 -0700 | [diff] [blame] | 176 | const struct spi_device_id *id_table; |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 177 | int (*probe)(struct spi_device *spi); |
| 178 | int (*remove)(struct spi_device *spi); |
| 179 | void (*shutdown)(struct spi_device *spi); |
| 180 | int (*suspend)(struct spi_device *spi, pm_message_t mesg); |
| 181 | int (*resume)(struct spi_device *spi); |
| 182 | struct device_driver driver; |
| 183 | }; |
| 184 | |
| 185 | static inline struct spi_driver *to_spi_driver(struct device_driver *drv) |
| 186 | { |
| 187 | return drv ? container_of(drv, struct spi_driver, driver) : NULL; |
| 188 | } |
| 189 | |
| 190 | extern int spi_register_driver(struct spi_driver *sdrv); |
| 191 | |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 192 | /** |
| 193 | * spi_unregister_driver - reverse effect of spi_register_driver |
| 194 | * @sdrv: the driver to unregister |
| 195 | * Context: can sleep |
| 196 | */ |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 197 | static inline void spi_unregister_driver(struct spi_driver *sdrv) |
| 198 | { |
Ben Dooks | ddc1e97 | 2007-02-12 00:52:43 -0800 | [diff] [blame] | 199 | if (sdrv) |
| 200 | driver_unregister(&sdrv->driver); |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 201 | } |
| 202 | |
Lars-Peter Clausen | 3acbb01 | 2011-11-16 10:13:37 +0100 | [diff] [blame] | 203 | /** |
| 204 | * module_spi_driver() - Helper macro for registering a SPI driver |
| 205 | * @__spi_driver: spi_driver struct |
| 206 | * |
| 207 | * Helper macro for SPI drivers which do not do anything special in module |
| 208 | * init/exit. This eliminates a lot of boilerplate. Each module may only |
| 209 | * use this macro once, and calling it replaces module_init() and module_exit() |
| 210 | */ |
| 211 | #define module_spi_driver(__spi_driver) \ |
| 212 | module_driver(__spi_driver, spi_register_driver, \ |
| 213 | spi_unregister_driver) |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 214 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 215 | /** |
| 216 | * struct spi_master - interface to SPI master controller |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 217 | * @dev: device interface to this driver |
Feng Tang | 2b9603a | 2010-08-02 15:52:15 +0800 | [diff] [blame] | 218 | * @list: link with the global spi_master list |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 219 | * @bus_num: board-specific (and often SOC-specific) identifier for a |
David Brownell | 747d844 | 2006-04-02 10:33:37 -0800 | [diff] [blame] | 220 | * given SPI controller. |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 221 | * @num_chipselect: chipselects are used to distinguish individual |
David Brownell | 747d844 | 2006-04-02 10:33:37 -0800 | [diff] [blame] | 222 | * SPI slaves, and are numbered from zero to num_chipselects. |
| 223 | * each slave has a chipselect signal, but it's common that not |
| 224 | * every chipselect is connected to a slave. |
Mike Rapoport | fd5e191 | 2009-04-06 19:00:56 -0700 | [diff] [blame] | 225 | * @dma_alignment: SPI controller constraint on DMA buffers alignment. |
Randy Dunlap | b73b255 | 2009-09-22 16:46:00 -0700 | [diff] [blame] | 226 | * @mode_bits: flags understood by this controller driver |
| 227 | * @flags: other constraints relevant to this driver |
Ernst Schwab | 5c79a5a | 2010-08-16 15:10:11 +0200 | [diff] [blame] | 228 | * @bus_lock_spinlock: spinlock for SPI bus locking |
| 229 | * @bus_lock_mutex: mutex for SPI bus locking |
| 230 | * @bus_lock_flag: indicates that the SPI bus is locked for exclusive use |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 231 | * @setup: updates the device mode and clocking records used by a |
David Brownell | 8022456 | 2007-02-12 00:52:46 -0800 | [diff] [blame] | 232 | * device's SPI controller; protocol code may call this. This |
| 233 | * must fail if an unrecognized or unsupported mode is requested. |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 234 | * It's always safe to call this unless transfers are pending on |
| 235 | * the device whose settings are being modified. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 236 | * @transfer: adds a message to the controller's transfer queue. |
| 237 | * @cleanup: frees controller-specific state |
| 238 | * |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 239 | * Each SPI master controller can communicate with one or more @spi_device |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 240 | * children. These make a small bus, sharing MOSI, MISO and SCK signals |
| 241 | * but not chip select signals. Each device may be configured to use a |
| 242 | * different clock rate, since those shared signals are ignored unless |
| 243 | * the chip is selected. |
| 244 | * |
| 245 | * The driver for an SPI controller manages access to those devices through |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 246 | * a queue of spi_message transactions, copying data between CPU memory and |
| 247 | * an SPI slave device. For each such message it queues, it calls the |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 248 | * message's completion function when the transaction completes. |
| 249 | */ |
| 250 | struct spi_master { |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 251 | struct device dev; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 252 | |
Feng Tang | 2b9603a | 2010-08-02 15:52:15 +0800 | [diff] [blame] | 253 | struct list_head list; |
| 254 | |
David Brownell | a020ed7 | 2006-04-03 15:49:04 -0700 | [diff] [blame] | 255 | /* other than negative (== assign one dynamically), bus_num is fully |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 256 | * board-specific. usually that simplifies to being SOC-specific. |
David Brownell | a020ed7 | 2006-04-03 15:49:04 -0700 | [diff] [blame] | 257 | * example: one SOC has three SPI controllers, numbered 0..2, |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 258 | * and one board's schematics might show it using SPI-2. software |
| 259 | * would normally use bus_num=2 for that controller. |
| 260 | */ |
David Brownell | a020ed7 | 2006-04-03 15:49:04 -0700 | [diff] [blame] | 261 | s16 bus_num; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 262 | |
| 263 | /* chipselects will be integral to many controllers; some others |
| 264 | * might use board-specific GPIOs. |
| 265 | */ |
| 266 | u16 num_chipselect; |
| 267 | |
Mike Rapoport | fd5e191 | 2009-04-06 19:00:56 -0700 | [diff] [blame] | 268 | /* some SPI controllers pose alignment requirements on DMAable |
| 269 | * buffers; let protocol drivers know about these requirements. |
| 270 | */ |
| 271 | u16 dma_alignment; |
| 272 | |
David Brownell | e7db06b | 2009-06-17 16:26:04 -0700 | [diff] [blame] | 273 | /* spi_device.mode flags understood by this controller driver */ |
| 274 | u16 mode_bits; |
| 275 | |
David Brownell | 70d6027 | 2009-06-30 11:41:27 -0700 | [diff] [blame] | 276 | /* other constraints relevant to this driver */ |
| 277 | u16 flags; |
| 278 | #define SPI_MASTER_HALF_DUPLEX BIT(0) /* can't do full duplex */ |
David Brownell | 568d069 | 2009-09-22 16:46:18 -0700 | [diff] [blame] | 279 | #define SPI_MASTER_NO_RX BIT(1) /* can't do buffer read */ |
| 280 | #define SPI_MASTER_NO_TX BIT(2) /* can't do buffer write */ |
David Brownell | 70d6027 | 2009-06-30 11:41:27 -0700 | [diff] [blame] | 281 | |
Ernst Schwab | cf32b71e | 2010-06-28 17:49:29 -0700 | [diff] [blame] | 282 | /* lock and mutex for SPI bus locking */ |
| 283 | spinlock_t bus_lock_spinlock; |
| 284 | struct mutex bus_lock_mutex; |
| 285 | |
| 286 | /* flag indicating that the SPI bus is locked for exclusive use */ |
| 287 | bool bus_lock_flag; |
| 288 | |
David Brownell | 6e538aa | 2009-04-21 12:24:49 -0700 | [diff] [blame] | 289 | /* Setup mode and clock, etc (spi driver may call many times). |
| 290 | * |
| 291 | * IMPORTANT: this may be called when transfers to another |
| 292 | * device are active. DO NOT UPDATE SHARED REGISTERS in ways |
| 293 | * which could break those transfers. |
| 294 | */ |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 295 | int (*setup)(struct spi_device *spi); |
| 296 | |
| 297 | /* bidirectional bulk transfers |
| 298 | * |
| 299 | * + The transfer() method may not sleep; its main role is |
| 300 | * just to add the message to the queue. |
| 301 | * + For now there's no remove-from-queue operation, or |
| 302 | * any other request management |
| 303 | * + To a given spi_device, message queueing is pure fifo |
| 304 | * |
| 305 | * + The master's main job is to process its message queue, |
| 306 | * selecting a chip then transferring data |
| 307 | * + If there are multiple spi_device children, the i/o queue |
| 308 | * arbitration algorithm is unspecified (round robin, fifo, |
| 309 | * priority, reservations, preemption, etc) |
| 310 | * |
| 311 | * + Chipselect stays active during the entire message |
| 312 | * (unless modified by spi_transfer.cs_change != 0). |
| 313 | * + The message transfers use clock and SPI mode parameters |
| 314 | * previously established by setup() for this device |
| 315 | */ |
| 316 | int (*transfer)(struct spi_device *spi, |
| 317 | struct spi_message *mesg); |
| 318 | |
| 319 | /* called on release() to free memory provided by spi_master */ |
Hans-Peter Nilsson | 0ffa028 | 2007-02-12 00:52:45 -0800 | [diff] [blame] | 320 | void (*cleanup)(struct spi_device *spi); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 321 | }; |
| 322 | |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 323 | static inline void *spi_master_get_devdata(struct spi_master *master) |
| 324 | { |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 325 | return dev_get_drvdata(&master->dev); |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 326 | } |
| 327 | |
| 328 | static inline void spi_master_set_devdata(struct spi_master *master, void *data) |
| 329 | { |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 330 | dev_set_drvdata(&master->dev, data); |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 331 | } |
| 332 | |
| 333 | static inline struct spi_master *spi_master_get(struct spi_master *master) |
| 334 | { |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 335 | if (!master || !get_device(&master->dev)) |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 336 | return NULL; |
| 337 | return master; |
| 338 | } |
| 339 | |
| 340 | static inline void spi_master_put(struct spi_master *master) |
| 341 | { |
| 342 | if (master) |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 343 | put_device(&master->dev); |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 344 | } |
| 345 | |
| 346 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 347 | /* the spi driver core manages memory for the spi_master classdev */ |
| 348 | extern struct spi_master * |
| 349 | spi_alloc_master(struct device *host, unsigned size); |
| 350 | |
| 351 | extern int spi_register_master(struct spi_master *master); |
| 352 | extern void spi_unregister_master(struct spi_master *master); |
| 353 | |
| 354 | extern struct spi_master *spi_busnum_to_master(u16 busnum); |
| 355 | |
| 356 | /*---------------------------------------------------------------------------*/ |
| 357 | |
| 358 | /* |
| 359 | * I/O INTERFACE between SPI controller and protocol drivers |
| 360 | * |
| 361 | * Protocol drivers use a queue of spi_messages, each transferring data |
| 362 | * between the controller and memory buffers. |
| 363 | * |
| 364 | * The spi_messages themselves consist of a series of read+write transfer |
| 365 | * segments. Those segments always read the same number of bits as they |
| 366 | * write; but one or the other is easily ignored by passing a null buffer |
| 367 | * pointer. (This is unlike most types of I/O API, because SPI hardware |
| 368 | * is full duplex.) |
| 369 | * |
| 370 | * NOTE: Allocation of spi_transfer and spi_message memory is entirely |
| 371 | * up to the protocol driver, which guarantees the integrity of both (as |
| 372 | * well as the data buffers) for as long as the message is queued. |
| 373 | */ |
| 374 | |
| 375 | /** |
| 376 | * struct spi_transfer - a read/write buffer pair |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 377 | * @tx_buf: data to be written (dma-safe memory), or NULL |
| 378 | * @rx_buf: data to be read (dma-safe memory), or NULL |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 379 | * @tx_dma: DMA address of tx_buf, if @spi_message.is_dma_mapped |
| 380 | * @rx_dma: DMA address of rx_buf, if @spi_message.is_dma_mapped |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 381 | * @len: size of rx and tx buffers (in bytes) |
Frederik Schwarzer | 025dfda | 2008-10-16 19:02:37 +0200 | [diff] [blame] | 382 | * @speed_hz: Select a speed other than the device default for this |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 383 | * transfer. If 0 the default (from @spi_device) is used. |
Frederik Schwarzer | 025dfda | 2008-10-16 19:02:37 +0200 | [diff] [blame] | 384 | * @bits_per_word: select a bits_per_word other than the device default |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 385 | * for this transfer. If 0 the default (from @spi_device) is used. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 386 | * @cs_change: affects chipselect after this transfer completes |
| 387 | * @delay_usecs: microseconds to delay after this transfer before |
David Brownell | 747d844 | 2006-04-02 10:33:37 -0800 | [diff] [blame] | 388 | * (optionally) changing the chipselect status, then starting |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 389 | * the next transfer or completing this @spi_message. |
| 390 | * @transfer_list: transfers are sequenced through @spi_message.transfers |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 391 | * |
| 392 | * SPI transfers always write the same number of bytes as they read. |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 393 | * Protocol drivers should always provide @rx_buf and/or @tx_buf. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 394 | * In some cases, they may also want to provide DMA addresses for |
| 395 | * the data being transferred; that may reduce overhead, when the |
| 396 | * underlying driver uses dma. |
| 397 | * |
David Brownell | 4b1badf | 2006-12-29 16:48:39 -0800 | [diff] [blame] | 398 | * If the transmit buffer is null, zeroes will be shifted out |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 399 | * while filling @rx_buf. If the receive buffer is null, the data |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 400 | * shifted in will be discarded. Only "len" bytes shift out (or in). |
| 401 | * It's an error to try to shift out a partial word. (For example, by |
| 402 | * shifting out three bytes with word size of sixteen or twenty bits; |
| 403 | * the former uses two bytes per word, the latter uses four bytes.) |
| 404 | * |
David Brownell | 8022456 | 2007-02-12 00:52:46 -0800 | [diff] [blame] | 405 | * In-memory data values are always in native CPU byte order, translated |
| 406 | * from the wire byte order (big-endian except with SPI_LSB_FIRST). So |
| 407 | * for example when bits_per_word is sixteen, buffers are 2N bytes long |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 408 | * (@len = 2N) and hold N sixteen bit words in CPU byte order. |
David Brownell | 8022456 | 2007-02-12 00:52:46 -0800 | [diff] [blame] | 409 | * |
| 410 | * When the word size of the SPI transfer is not a power-of-two multiple |
| 411 | * of eight bits, those in-memory words include extra bits. In-memory |
| 412 | * words are always seen by protocol drivers as right-justified, so the |
| 413 | * undefined (rx) or unused (tx) bits are always the most significant bits. |
| 414 | * |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 415 | * All SPI transfers start with the relevant chipselect active. Normally |
| 416 | * it stays selected until after the last transfer in a message. Drivers |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 417 | * can affect the chipselect signal using cs_change. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 418 | * |
| 419 | * (i) If the transfer isn't the last one in the message, this flag is |
| 420 | * used to make the chipselect briefly go inactive in the middle of the |
| 421 | * message. Toggling chipselect in this way may be needed to terminate |
| 422 | * a chip command, letting a single spi_message perform all of group of |
| 423 | * chip transactions together. |
| 424 | * |
| 425 | * (ii) When the transfer is the last one in the message, the chip may |
David Brownell | f5a9c77 | 2007-06-16 10:16:08 -0700 | [diff] [blame] | 426 | * stay selected until the next transfer. On multi-device SPI busses |
| 427 | * with nothing blocking messages going to other devices, this is just |
| 428 | * a performance hint; starting a message to another device deselects |
| 429 | * this one. But in other cases, this can be used to ensure correctness. |
| 430 | * Some devices need protocol transactions to be built from a series of |
| 431 | * spi_message submissions, where the content of one message is determined |
| 432 | * by the results of previous messages and where the whole transaction |
| 433 | * ends when the chipselect goes intactive. |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 434 | * |
| 435 | * The code that submits an spi_message (and its spi_transfers) |
| 436 | * to the lower layers is responsible for managing its memory. |
| 437 | * Zero-initialize every field you don't set up explicitly, to |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 438 | * insulate against future API updates. After you submit a message |
| 439 | * and its transfers, ignore them until its completion callback. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 440 | */ |
| 441 | struct spi_transfer { |
| 442 | /* it's ok if tx_buf == rx_buf (right?) |
| 443 | * for MicroWire, one buffer must be null |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 444 | * buffers must work with dma_*map_single() calls, unless |
| 445 | * spi_message.is_dma_mapped reports a pre-existing mapping |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 446 | */ |
| 447 | const void *tx_buf; |
| 448 | void *rx_buf; |
| 449 | unsigned len; |
| 450 | |
| 451 | dma_addr_t tx_dma; |
| 452 | dma_addr_t rx_dma; |
| 453 | |
| 454 | unsigned cs_change:1; |
Imre Deak | 4cff33f | 2006-02-17 10:02:18 -0800 | [diff] [blame] | 455 | u8 bits_per_word; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 456 | u16 delay_usecs; |
Imre Deak | 4cff33f | 2006-02-17 10:02:18 -0800 | [diff] [blame] | 457 | u32 speed_hz; |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 458 | |
| 459 | struct list_head transfer_list; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 460 | }; |
| 461 | |
| 462 | /** |
| 463 | * struct spi_message - one multi-segment SPI transaction |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 464 | * @transfers: list of transfer segments in this transaction |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 465 | * @spi: SPI device to which the transaction is queued |
| 466 | * @is_dma_mapped: if true, the caller provided both dma and cpu virtual |
| 467 | * addresses for each transfer buffer |
| 468 | * @complete: called to report transaction completions |
| 469 | * @context: the argument to complete() when it's called |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 470 | * @actual_length: the total number of bytes that were transferred in all |
| 471 | * successful segments |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 472 | * @status: zero for success, else negative errno |
| 473 | * @queue: for use by whichever driver currently owns the message |
| 474 | * @state: for use by whichever driver currently owns the message |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 475 | * |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 476 | * A @spi_message is used to execute an atomic sequence of data transfers, |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 477 | * each represented by a struct spi_transfer. The sequence is "atomic" |
| 478 | * in the sense that no other spi_message may use that SPI bus until that |
| 479 | * sequence completes. On some systems, many such sequences can execute as |
| 480 | * as single programmed DMA transfer. On all systems, these messages are |
| 481 | * queued, and might complete after transactions to other devices. Messages |
| 482 | * sent to a given spi_device are alway executed in FIFO order. |
| 483 | * |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 484 | * The code that submits an spi_message (and its spi_transfers) |
| 485 | * to the lower layers is responsible for managing its memory. |
| 486 | * Zero-initialize every field you don't set up explicitly, to |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 487 | * insulate against future API updates. After you submit a message |
| 488 | * and its transfers, ignore them until its completion callback. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 489 | */ |
| 490 | struct spi_message { |
David Brownell | 747d844 | 2006-04-02 10:33:37 -0800 | [diff] [blame] | 491 | struct list_head transfers; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 492 | |
| 493 | struct spi_device *spi; |
| 494 | |
| 495 | unsigned is_dma_mapped:1; |
| 496 | |
| 497 | /* REVISIT: we might want a flag affecting the behavior of the |
| 498 | * last transfer ... allowing things like "read 16 bit length L" |
| 499 | * immediately followed by "read L bytes". Basically imposing |
| 500 | * a specific message scheduling algorithm. |
| 501 | * |
| 502 | * Some controller drivers (message-at-a-time queue processing) |
| 503 | * could provide that as their default scheduling algorithm. But |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 504 | * others (with multi-message pipelines) could need a flag to |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 505 | * tell them about such special cases. |
| 506 | */ |
| 507 | |
| 508 | /* completion is reported through a callback */ |
David Brownell | 747d844 | 2006-04-02 10:33:37 -0800 | [diff] [blame] | 509 | void (*complete)(void *context); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 510 | void *context; |
| 511 | unsigned actual_length; |
| 512 | int status; |
| 513 | |
| 514 | /* for optional use by whatever driver currently owns the |
| 515 | * spi_message ... between calls to spi_async and then later |
| 516 | * complete(), that's the spi_master controller driver. |
| 517 | */ |
| 518 | struct list_head queue; |
| 519 | void *state; |
| 520 | }; |
| 521 | |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 522 | static inline void spi_message_init(struct spi_message *m) |
| 523 | { |
| 524 | memset(m, 0, sizeof *m); |
| 525 | INIT_LIST_HEAD(&m->transfers); |
| 526 | } |
| 527 | |
| 528 | static inline void |
| 529 | spi_message_add_tail(struct spi_transfer *t, struct spi_message *m) |
| 530 | { |
| 531 | list_add_tail(&t->transfer_list, &m->transfers); |
| 532 | } |
| 533 | |
| 534 | static inline void |
| 535 | spi_transfer_del(struct spi_transfer *t) |
| 536 | { |
| 537 | list_del(&t->transfer_list); |
| 538 | } |
| 539 | |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 540 | /* It's fine to embed message and transaction structures in other data |
| 541 | * structures so long as you don't free them while they're in use. |
| 542 | */ |
| 543 | |
| 544 | static inline struct spi_message *spi_message_alloc(unsigned ntrans, gfp_t flags) |
| 545 | { |
| 546 | struct spi_message *m; |
| 547 | |
| 548 | m = kzalloc(sizeof(struct spi_message) |
| 549 | + ntrans * sizeof(struct spi_transfer), |
| 550 | flags); |
| 551 | if (m) { |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 552 | int i; |
| 553 | struct spi_transfer *t = (struct spi_transfer *)(m + 1); |
| 554 | |
| 555 | INIT_LIST_HEAD(&m->transfers); |
| 556 | for (i = 0; i < ntrans; i++, t++) |
| 557 | spi_message_add_tail(t, m); |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 558 | } |
| 559 | return m; |
| 560 | } |
| 561 | |
| 562 | static inline void spi_message_free(struct spi_message *m) |
| 563 | { |
| 564 | kfree(m); |
| 565 | } |
| 566 | |
David Brownell | 7d07719 | 2009-06-17 16:26:03 -0700 | [diff] [blame] | 567 | extern int spi_setup(struct spi_device *spi); |
David Brownell | 568d069 | 2009-09-22 16:46:18 -0700 | [diff] [blame] | 568 | extern int spi_async(struct spi_device *spi, struct spi_message *message); |
Ernst Schwab | cf32b71e | 2010-06-28 17:49:29 -0700 | [diff] [blame] | 569 | extern int spi_async_locked(struct spi_device *spi, |
| 570 | struct spi_message *message); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 571 | |
| 572 | /*---------------------------------------------------------------------------*/ |
| 573 | |
| 574 | /* All these synchronous SPI transfer routines are utilities layered |
| 575 | * over the core async transfer primitive. Here, "synchronous" means |
| 576 | * they will sleep uninterruptibly until the async transfer completes. |
| 577 | */ |
| 578 | |
| 579 | extern int spi_sync(struct spi_device *spi, struct spi_message *message); |
Ernst Schwab | cf32b71e | 2010-06-28 17:49:29 -0700 | [diff] [blame] | 580 | extern int spi_sync_locked(struct spi_device *spi, struct spi_message *message); |
| 581 | extern int spi_bus_lock(struct spi_master *master); |
| 582 | extern int spi_bus_unlock(struct spi_master *master); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 583 | |
| 584 | /** |
| 585 | * spi_write - SPI synchronous write |
| 586 | * @spi: device to which data will be written |
| 587 | * @buf: data buffer |
| 588 | * @len: data buffer size |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 589 | * Context: can sleep |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 590 | * |
| 591 | * This writes the buffer and returns zero or a negative error code. |
| 592 | * Callable only from contexts that can sleep. |
| 593 | */ |
| 594 | static inline int |
Mark Brown | 0c4a159 | 2011-05-11 00:09:30 +0200 | [diff] [blame] | 595 | spi_write(struct spi_device *spi, const void *buf, size_t len) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 596 | { |
| 597 | struct spi_transfer t = { |
| 598 | .tx_buf = buf, |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 599 | .len = len, |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 600 | }; |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 601 | struct spi_message m; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 602 | |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 603 | spi_message_init(&m); |
| 604 | spi_message_add_tail(&t, &m); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 605 | return spi_sync(spi, &m); |
| 606 | } |
| 607 | |
| 608 | /** |
| 609 | * spi_read - SPI synchronous read |
| 610 | * @spi: device from which data will be read |
| 611 | * @buf: data buffer |
| 612 | * @len: data buffer size |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 613 | * Context: can sleep |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 614 | * |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 615 | * This reads the buffer and returns zero or a negative error code. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 616 | * Callable only from contexts that can sleep. |
| 617 | */ |
| 618 | static inline int |
Mark Brown | 0c4a159 | 2011-05-11 00:09:30 +0200 | [diff] [blame] | 619 | spi_read(struct spi_device *spi, void *buf, size_t len) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 620 | { |
| 621 | struct spi_transfer t = { |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 622 | .rx_buf = buf, |
| 623 | .len = len, |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 624 | }; |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 625 | struct spi_message m; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 626 | |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 627 | spi_message_init(&m); |
| 628 | spi_message_add_tail(&t, &m); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 629 | return spi_sync(spi, &m); |
| 630 | } |
| 631 | |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 632 | /* this copies txbuf and rxbuf data; for small transfers only! */ |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 633 | extern int spi_write_then_read(struct spi_device *spi, |
Mark Brown | 0c4a159 | 2011-05-11 00:09:30 +0200 | [diff] [blame] | 634 | const void *txbuf, unsigned n_tx, |
| 635 | void *rxbuf, unsigned n_rx); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 636 | |
| 637 | /** |
| 638 | * spi_w8r8 - SPI synchronous 8 bit write followed by 8 bit read |
| 639 | * @spi: device with which data will be exchanged |
| 640 | * @cmd: command to be written before data is read back |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 641 | * Context: can sleep |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 642 | * |
| 643 | * This returns the (unsigned) eight bit number returned by the |
| 644 | * device, or else a negative error code. Callable only from |
| 645 | * contexts that can sleep. |
| 646 | */ |
| 647 | static inline ssize_t spi_w8r8(struct spi_device *spi, u8 cmd) |
| 648 | { |
| 649 | ssize_t status; |
| 650 | u8 result; |
| 651 | |
| 652 | status = spi_write_then_read(spi, &cmd, 1, &result, 1); |
| 653 | |
| 654 | /* return negative errno or unsigned value */ |
| 655 | return (status < 0) ? status : result; |
| 656 | } |
| 657 | |
| 658 | /** |
| 659 | * spi_w8r16 - SPI synchronous 8 bit write followed by 16 bit read |
| 660 | * @spi: device with which data will be exchanged |
| 661 | * @cmd: command to be written before data is read back |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 662 | * Context: can sleep |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 663 | * |
| 664 | * This returns the (unsigned) sixteen bit number returned by the |
| 665 | * device, or else a negative error code. Callable only from |
| 666 | * contexts that can sleep. |
| 667 | * |
| 668 | * The number is returned in wire-order, which is at least sometimes |
| 669 | * big-endian. |
| 670 | */ |
| 671 | static inline ssize_t spi_w8r16(struct spi_device *spi, u8 cmd) |
| 672 | { |
| 673 | ssize_t status; |
| 674 | u16 result; |
| 675 | |
| 676 | status = spi_write_then_read(spi, &cmd, 1, (u8 *) &result, 2); |
| 677 | |
| 678 | /* return negative errno or unsigned value */ |
| 679 | return (status < 0) ? status : result; |
| 680 | } |
| 681 | |
| 682 | /*---------------------------------------------------------------------------*/ |
| 683 | |
| 684 | /* |
| 685 | * INTERFACE between board init code and SPI infrastructure. |
| 686 | * |
| 687 | * No SPI driver ever sees these SPI device table segments, but |
| 688 | * it's how the SPI core (or adapters that get hotplugged) grows |
| 689 | * the driver model tree. |
| 690 | * |
| 691 | * As a rule, SPI devices can't be probed. Instead, board init code |
| 692 | * provides a table listing the devices which are present, with enough |
| 693 | * information to bind and set up the device's driver. There's basic |
| 694 | * support for nonstatic configurations too; enough to handle adding |
| 695 | * parport adapters, or microcontrollers acting as USB-to-SPI bridges. |
| 696 | */ |
| 697 | |
David Brownell | 2604288 | 2007-07-31 00:39:44 -0700 | [diff] [blame] | 698 | /** |
| 699 | * struct spi_board_info - board-specific template for a SPI device |
| 700 | * @modalias: Initializes spi_device.modalias; identifies the driver. |
| 701 | * @platform_data: Initializes spi_device.platform_data; the particular |
| 702 | * data stored there is driver-specific. |
| 703 | * @controller_data: Initializes spi_device.controller_data; some |
| 704 | * controllers need hints about hardware setup, e.g. for DMA. |
| 705 | * @irq: Initializes spi_device.irq; depends on how the board is wired. |
| 706 | * @max_speed_hz: Initializes spi_device.max_speed_hz; based on limits |
| 707 | * from the chip datasheet and board-specific signal quality issues. |
| 708 | * @bus_num: Identifies which spi_master parents the spi_device; unused |
| 709 | * by spi_new_device(), and otherwise depends on board wiring. |
| 710 | * @chip_select: Initializes spi_device.chip_select; depends on how |
| 711 | * the board is wired. |
| 712 | * @mode: Initializes spi_device.mode; based on the chip datasheet, board |
| 713 | * wiring (some devices support both 3WIRE and standard modes), and |
| 714 | * possibly presence of an inverter in the chipselect path. |
| 715 | * |
| 716 | * When adding new SPI devices to the device tree, these structures serve |
| 717 | * as a partial device template. They hold information which can't always |
| 718 | * be determined by drivers. Information that probe() can establish (such |
| 719 | * as the default transfer wordsize) is not included here. |
| 720 | * |
| 721 | * These structures are used in two places. Their primary role is to |
| 722 | * be stored in tables of board-specific device descriptors, which are |
| 723 | * declared early in board initialization and then used (much later) to |
| 724 | * populate a controller's device tree after the that controller's driver |
| 725 | * initializes. A secondary (and atypical) role is as a parameter to |
| 726 | * spi_new_device() call, which happens after those controller drivers |
| 727 | * are active in some dynamic board configuration models. |
| 728 | */ |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 729 | struct spi_board_info { |
| 730 | /* the device name and module name are coupled, like platform_bus; |
| 731 | * "modalias" is normally the driver name. |
| 732 | * |
| 733 | * platform_data goes to spi_device.dev.platform_data, |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 734 | * controller_data goes to spi_device.controller_data, |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 735 | * irq is copied too |
| 736 | */ |
Anton Vorontsov | 75368bf | 2009-09-22 16:46:04 -0700 | [diff] [blame] | 737 | char modalias[SPI_NAME_SIZE]; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 738 | const void *platform_data; |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 739 | void *controller_data; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 740 | int irq; |
| 741 | |
| 742 | /* slower signaling on noisy or low voltage boards */ |
| 743 | u32 max_speed_hz; |
| 744 | |
| 745 | |
| 746 | /* bus_num is board specific and matches the bus_num of some |
| 747 | * spi_master that will probably be registered later. |
| 748 | * |
| 749 | * chip_select reflects how this chip is wired to that master; |
| 750 | * it's less than num_chipselect. |
| 751 | */ |
| 752 | u16 bus_num; |
| 753 | u16 chip_select; |
| 754 | |
David Brownell | 980a01c | 2006-06-28 07:47:15 -0700 | [diff] [blame] | 755 | /* mode becomes spi_device.mode, and is essential for chips |
| 756 | * where the default of SPI_CS_HIGH = 0 is wrong. |
| 757 | */ |
| 758 | u8 mode; |
| 759 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 760 | /* ... may need additional spi_device chip config data here. |
| 761 | * avoid stuff protocol drivers can set; but include stuff |
| 762 | * needed to behave without being bound to a driver: |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 763 | * - quirks like clock rate mattering when not selected |
| 764 | */ |
| 765 | }; |
| 766 | |
| 767 | #ifdef CONFIG_SPI |
| 768 | extern int |
| 769 | spi_register_board_info(struct spi_board_info const *info, unsigned n); |
| 770 | #else |
| 771 | /* board init code may ignore whether SPI is configured or not */ |
| 772 | static inline int |
| 773 | spi_register_board_info(struct spi_board_info const *info, unsigned n) |
| 774 | { return 0; } |
| 775 | #endif |
| 776 | |
| 777 | |
| 778 | /* If you're hotplugging an adapter with devices (parport, usb, etc) |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 779 | * use spi_new_device() to describe each device. You can also call |
| 780 | * spi_unregister_device() to start making that device vanish, but |
| 781 | * normally that would be handled by spi_unregister_master(). |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 782 | * |
| 783 | * You can also use spi_alloc_device() and spi_add_device() to use a two |
| 784 | * stage registration sequence for each spi_device. This gives the caller |
| 785 | * some more control over the spi_device structure before it is registered, |
| 786 | * but requires that caller to initialize fields that would otherwise |
| 787 | * be defined using the board info. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 788 | */ |
| 789 | extern struct spi_device * |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 790 | spi_alloc_device(struct spi_master *master); |
| 791 | |
| 792 | extern int |
| 793 | spi_add_device(struct spi_device *spi); |
| 794 | |
| 795 | extern struct spi_device * |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 796 | spi_new_device(struct spi_master *, struct spi_board_info *); |
| 797 | |
| 798 | static inline void |
| 799 | spi_unregister_device(struct spi_device *spi) |
| 800 | { |
| 801 | if (spi) |
| 802 | device_unregister(&spi->dev); |
| 803 | } |
| 804 | |
Anton Vorontsov | 75368bf | 2009-09-22 16:46:04 -0700 | [diff] [blame] | 805 | extern const struct spi_device_id * |
| 806 | spi_get_device_id(const struct spi_device *sdev); |
| 807 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 808 | #endif /* __LINUX_SPI_H */ |