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8ae12a0d DB |
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 | ||
0a30c5ce | 22 | #include <linux/device.h> |
75368bf6 | 23 | #include <linux/mod_devicetable.h> |
5a0e3ad6 | 24 | #include <linux/slab.h> |
0a30c5ce | 25 | |
8ae12a0d | 26 | /* |
b885244e | 27 | * INTERFACES between SPI master-side drivers and SPI infrastructure. |
8ae12a0d | 28 | * (There's no SPI slave support for Linux yet...) |
8ae12a0d DB |
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. | |
4cff33f9 | 38 | * The spi_transfer.speed_hz can override this for each transfer. |
33e34dc6 | 39 | * @chip_select: Chipselect, distinguishing chips handled by @master. |
8ae12a0d DB |
40 | * @mode: The spi mode defines how data is clocked out and in. |
41 | * This may be changed by the device's driver. | |
33e34dc6 DB |
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). | |
8ae12a0d | 45 | * @bits_per_word: Data transfers involve one or more words; word sizes |
747d844e | 46 | * like eight or 12 bits are common. In-memory wordsizes are |
8ae12a0d | 47 | * powers of two bytes (e.g. 20 bit samples use 32 bits). |
ccf77cc4 DB |
48 | * This may be changed by the device's driver, or left at the |
49 | * default (0) indicating protocol words are eight bit bytes. | |
4cff33f9 | 50 | * The spi_transfer.bits_per_word can override this for each transfer. |
8ae12a0d | 51 | * @irq: Negative, or the number passed to request_irq() to receive |
747d844e | 52 | * interrupts from this device. |
8ae12a0d | 53 | * @controller_state: Controller's runtime state |
b885244e | 54 | * @controller_data: Board-specific definitions for controller, such as |
747d844e | 55 | * FIFO initialization parameters; from board_info.controller_data |
33e34dc6 DB |
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 | |
8ae12a0d | 59 | * |
33e34dc6 | 60 | * A @spi_device is used to interchange data between an SPI slave |
8ae12a0d DB |
61 | * (usually a discrete chip) and CPU memory. |
62 | * | |
33e34dc6 | 63 | * In @dev, the platform_data is used to hold information about this |
8ae12a0d DB |
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 | |
33e34dc6 DB |
66 | * variant with slightly different functionality; another might be |
67 | * information about how this particular board wires the chip's pins. | |
8ae12a0d DB |
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; | |
b885244e DB |
75 | #define SPI_CPHA 0x01 /* clock phase */ |
76 | #define SPI_CPOL 0x02 /* clock polarity */ | |
0c868461 DB |
77 | #define SPI_MODE_0 (0|0) /* (original MicroWire) */ |
78 | #define SPI_MODE_1 (0|SPI_CPHA) | |
8ae12a0d DB |
79 | #define SPI_MODE_2 (SPI_CPOL|0) |
80 | #define SPI_MODE_3 (SPI_CPOL|SPI_CPHA) | |
b885244e | 81 | #define SPI_CS_HIGH 0x04 /* chipselect active high? */ |
ccf77cc4 | 82 | #define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */ |
c06e677a | 83 | #define SPI_3WIRE 0x10 /* SI/SO signals shared */ |
4ef7af50 | 84 | #define SPI_LOOP 0x20 /* loopback mode */ |
b55f627f DB |
85 | #define SPI_NO_CS 0x40 /* 1 dev/bus, no chipselect */ |
86 | #define SPI_READY 0x80 /* slave pulls low to pause */ | |
8ae12a0d DB |
87 | u8 bits_per_word; |
88 | int irq; | |
89 | void *controller_state; | |
b885244e | 90 | void *controller_data; |
75368bf6 | 91 | char modalias[SPI_NAME_SIZE]; |
8ae12a0d | 92 | |
33e34dc6 DB |
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 | */ | |
8ae12a0d DB |
102 | }; |
103 | ||
104 | static inline struct spi_device *to_spi_device(struct device *dev) | |
105 | { | |
b885244e | 106 | return dev ? container_of(dev, struct spi_device, dev) : NULL; |
8ae12a0d DB |
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 | ||
9b40ff4d BD |
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 | } | |
8ae12a0d DB |
143 | |
144 | struct spi_message; | |
145 | ||
146 | ||
b885244e | 147 | |
2604288f DB |
148 | /** |
149 | * struct spi_driver - Host side "protocol" driver | |
75368bf6 | 150 | * @id_table: List of SPI devices supported by this driver |
2604288f DB |
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 | */ | |
b885244e | 175 | struct spi_driver { |
75368bf6 | 176 | const struct spi_device_id *id_table; |
b885244e DB |
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 | ||
33e34dc6 DB |
192 | /** |
193 | * spi_unregister_driver - reverse effect of spi_register_driver | |
194 | * @sdrv: the driver to unregister | |
195 | * Context: can sleep | |
196 | */ | |
b885244e DB |
197 | static inline void spi_unregister_driver(struct spi_driver *sdrv) |
198 | { | |
ddc1e975 BD |
199 | if (sdrv) |
200 | driver_unregister(&sdrv->driver); | |
b885244e DB |
201 | } |
202 | ||
203 | ||
8ae12a0d DB |
204 | /** |
205 | * struct spi_master - interface to SPI master controller | |
49dce689 | 206 | * @dev: device interface to this driver |
8ae12a0d | 207 | * @bus_num: board-specific (and often SOC-specific) identifier for a |
747d844e | 208 | * given SPI controller. |
b885244e | 209 | * @num_chipselect: chipselects are used to distinguish individual |
747d844e DB |
210 | * SPI slaves, and are numbered from zero to num_chipselects. |
211 | * each slave has a chipselect signal, but it's common that not | |
212 | * every chipselect is connected to a slave. | |
fd5e191e | 213 | * @dma_alignment: SPI controller constraint on DMA buffers alignment. |
b73b2559 RD |
214 | * @mode_bits: flags understood by this controller driver |
215 | * @flags: other constraints relevant to this driver | |
8ae12a0d | 216 | * @setup: updates the device mode and clocking records used by a |
80224561 DB |
217 | * device's SPI controller; protocol code may call this. This |
218 | * must fail if an unrecognized or unsupported mode is requested. | |
33e34dc6 DB |
219 | * It's always safe to call this unless transfers are pending on |
220 | * the device whose settings are being modified. | |
8ae12a0d DB |
221 | * @transfer: adds a message to the controller's transfer queue. |
222 | * @cleanup: frees controller-specific state | |
223 | * | |
33e34dc6 | 224 | * Each SPI master controller can communicate with one or more @spi_device |
8ae12a0d DB |
225 | * children. These make a small bus, sharing MOSI, MISO and SCK signals |
226 | * but not chip select signals. Each device may be configured to use a | |
227 | * different clock rate, since those shared signals are ignored unless | |
228 | * the chip is selected. | |
229 | * | |
230 | * The driver for an SPI controller manages access to those devices through | |
33e34dc6 DB |
231 | * a queue of spi_message transactions, copying data between CPU memory and |
232 | * an SPI slave device. For each such message it queues, it calls the | |
8ae12a0d DB |
233 | * message's completion function when the transaction completes. |
234 | */ | |
235 | struct spi_master { | |
49dce689 | 236 | struct device dev; |
8ae12a0d | 237 | |
a020ed75 | 238 | /* other than negative (== assign one dynamically), bus_num is fully |
8ae12a0d | 239 | * board-specific. usually that simplifies to being SOC-specific. |
a020ed75 | 240 | * example: one SOC has three SPI controllers, numbered 0..2, |
8ae12a0d DB |
241 | * and one board's schematics might show it using SPI-2. software |
242 | * would normally use bus_num=2 for that controller. | |
243 | */ | |
a020ed75 | 244 | s16 bus_num; |
8ae12a0d DB |
245 | |
246 | /* chipselects will be integral to many controllers; some others | |
247 | * might use board-specific GPIOs. | |
248 | */ | |
249 | u16 num_chipselect; | |
250 | ||
fd5e191e MR |
251 | /* some SPI controllers pose alignment requirements on DMAable |
252 | * buffers; let protocol drivers know about these requirements. | |
253 | */ | |
254 | u16 dma_alignment; | |
255 | ||
e7db06b5 DB |
256 | /* spi_device.mode flags understood by this controller driver */ |
257 | u16 mode_bits; | |
258 | ||
70d6027f DB |
259 | /* other constraints relevant to this driver */ |
260 | u16 flags; | |
261 | #define SPI_MASTER_HALF_DUPLEX BIT(0) /* can't do full duplex */ | |
568d0697 DB |
262 | #define SPI_MASTER_NO_RX BIT(1) /* can't do buffer read */ |
263 | #define SPI_MASTER_NO_TX BIT(2) /* can't do buffer write */ | |
70d6027f | 264 | |
6e538aaf DB |
265 | /* Setup mode and clock, etc (spi driver may call many times). |
266 | * | |
267 | * IMPORTANT: this may be called when transfers to another | |
268 | * device are active. DO NOT UPDATE SHARED REGISTERS in ways | |
269 | * which could break those transfers. | |
270 | */ | |
8ae12a0d DB |
271 | int (*setup)(struct spi_device *spi); |
272 | ||
273 | /* bidirectional bulk transfers | |
274 | * | |
275 | * + The transfer() method may not sleep; its main role is | |
276 | * just to add the message to the queue. | |
277 | * + For now there's no remove-from-queue operation, or | |
278 | * any other request management | |
279 | * + To a given spi_device, message queueing is pure fifo | |
280 | * | |
281 | * + The master's main job is to process its message queue, | |
282 | * selecting a chip then transferring data | |
283 | * + If there are multiple spi_device children, the i/o queue | |
284 | * arbitration algorithm is unspecified (round robin, fifo, | |
285 | * priority, reservations, preemption, etc) | |
286 | * | |
287 | * + Chipselect stays active during the entire message | |
288 | * (unless modified by spi_transfer.cs_change != 0). | |
289 | * + The message transfers use clock and SPI mode parameters | |
290 | * previously established by setup() for this device | |
291 | */ | |
292 | int (*transfer)(struct spi_device *spi, | |
293 | struct spi_message *mesg); | |
294 | ||
295 | /* called on release() to free memory provided by spi_master */ | |
0ffa0285 | 296 | void (*cleanup)(struct spi_device *spi); |
8ae12a0d DB |
297 | }; |
298 | ||
0c868461 DB |
299 | static inline void *spi_master_get_devdata(struct spi_master *master) |
300 | { | |
49dce689 | 301 | return dev_get_drvdata(&master->dev); |
0c868461 DB |
302 | } |
303 | ||
304 | static inline void spi_master_set_devdata(struct spi_master *master, void *data) | |
305 | { | |
49dce689 | 306 | dev_set_drvdata(&master->dev, data); |
0c868461 DB |
307 | } |
308 | ||
309 | static inline struct spi_master *spi_master_get(struct spi_master *master) | |
310 | { | |
49dce689 | 311 | if (!master || !get_device(&master->dev)) |
0c868461 DB |
312 | return NULL; |
313 | return master; | |
314 | } | |
315 | ||
316 | static inline void spi_master_put(struct spi_master *master) | |
317 | { | |
318 | if (master) | |
49dce689 | 319 | put_device(&master->dev); |
0c868461 DB |
320 | } |
321 | ||
322 | ||
8ae12a0d DB |
323 | /* the spi driver core manages memory for the spi_master classdev */ |
324 | extern struct spi_master * | |
325 | spi_alloc_master(struct device *host, unsigned size); | |
326 | ||
327 | extern int spi_register_master(struct spi_master *master); | |
328 | extern void spi_unregister_master(struct spi_master *master); | |
329 | ||
330 | extern struct spi_master *spi_busnum_to_master(u16 busnum); | |
331 | ||
332 | /*---------------------------------------------------------------------------*/ | |
333 | ||
334 | /* | |
335 | * I/O INTERFACE between SPI controller and protocol drivers | |
336 | * | |
337 | * Protocol drivers use a queue of spi_messages, each transferring data | |
338 | * between the controller and memory buffers. | |
339 | * | |
340 | * The spi_messages themselves consist of a series of read+write transfer | |
341 | * segments. Those segments always read the same number of bits as they | |
342 | * write; but one or the other is easily ignored by passing a null buffer | |
343 | * pointer. (This is unlike most types of I/O API, because SPI hardware | |
344 | * is full duplex.) | |
345 | * | |
346 | * NOTE: Allocation of spi_transfer and spi_message memory is entirely | |
347 | * up to the protocol driver, which guarantees the integrity of both (as | |
348 | * well as the data buffers) for as long as the message is queued. | |
349 | */ | |
350 | ||
351 | /** | |
352 | * struct spi_transfer - a read/write buffer pair | |
8275c642 VW |
353 | * @tx_buf: data to be written (dma-safe memory), or NULL |
354 | * @rx_buf: data to be read (dma-safe memory), or NULL | |
33e34dc6 DB |
355 | * @tx_dma: DMA address of tx_buf, if @spi_message.is_dma_mapped |
356 | * @rx_dma: DMA address of rx_buf, if @spi_message.is_dma_mapped | |
8ae12a0d | 357 | * @len: size of rx and tx buffers (in bytes) |
025dfdaf | 358 | * @speed_hz: Select a speed other than the device default for this |
33e34dc6 | 359 | * transfer. If 0 the default (from @spi_device) is used. |
025dfdaf | 360 | * @bits_per_word: select a bits_per_word other than the device default |
33e34dc6 | 361 | * for this transfer. If 0 the default (from @spi_device) is used. |
8ae12a0d DB |
362 | * @cs_change: affects chipselect after this transfer completes |
363 | * @delay_usecs: microseconds to delay after this transfer before | |
747d844e | 364 | * (optionally) changing the chipselect status, then starting |
33e34dc6 DB |
365 | * the next transfer or completing this @spi_message. |
366 | * @transfer_list: transfers are sequenced through @spi_message.transfers | |
8ae12a0d DB |
367 | * |
368 | * SPI transfers always write the same number of bytes as they read. | |
33e34dc6 | 369 | * Protocol drivers should always provide @rx_buf and/or @tx_buf. |
8ae12a0d DB |
370 | * In some cases, they may also want to provide DMA addresses for |
371 | * the data being transferred; that may reduce overhead, when the | |
372 | * underlying driver uses dma. | |
373 | * | |
4b1badf5 | 374 | * If the transmit buffer is null, zeroes will be shifted out |
33e34dc6 | 375 | * while filling @rx_buf. If the receive buffer is null, the data |
8275c642 VW |
376 | * shifted in will be discarded. Only "len" bytes shift out (or in). |
377 | * It's an error to try to shift out a partial word. (For example, by | |
378 | * shifting out three bytes with word size of sixteen or twenty bits; | |
379 | * the former uses two bytes per word, the latter uses four bytes.) | |
380 | * | |
80224561 DB |
381 | * In-memory data values are always in native CPU byte order, translated |
382 | * from the wire byte order (big-endian except with SPI_LSB_FIRST). So | |
383 | * for example when bits_per_word is sixteen, buffers are 2N bytes long | |
33e34dc6 | 384 | * (@len = 2N) and hold N sixteen bit words in CPU byte order. |
80224561 DB |
385 | * |
386 | * When the word size of the SPI transfer is not a power-of-two multiple | |
387 | * of eight bits, those in-memory words include extra bits. In-memory | |
388 | * words are always seen by protocol drivers as right-justified, so the | |
389 | * undefined (rx) or unused (tx) bits are always the most significant bits. | |
390 | * | |
8275c642 VW |
391 | * All SPI transfers start with the relevant chipselect active. Normally |
392 | * it stays selected until after the last transfer in a message. Drivers | |
33e34dc6 | 393 | * can affect the chipselect signal using cs_change. |
8ae12a0d DB |
394 | * |
395 | * (i) If the transfer isn't the last one in the message, this flag is | |
396 | * used to make the chipselect briefly go inactive in the middle of the | |
397 | * message. Toggling chipselect in this way may be needed to terminate | |
398 | * a chip command, letting a single spi_message perform all of group of | |
399 | * chip transactions together. | |
400 | * | |
401 | * (ii) When the transfer is the last one in the message, the chip may | |
f5a9c77d DB |
402 | * stay selected until the next transfer. On multi-device SPI busses |
403 | * with nothing blocking messages going to other devices, this is just | |
404 | * a performance hint; starting a message to another device deselects | |
405 | * this one. But in other cases, this can be used to ensure correctness. | |
406 | * Some devices need protocol transactions to be built from a series of | |
407 | * spi_message submissions, where the content of one message is determined | |
408 | * by the results of previous messages and where the whole transaction | |
409 | * ends when the chipselect goes intactive. | |
0c868461 DB |
410 | * |
411 | * The code that submits an spi_message (and its spi_transfers) | |
412 | * to the lower layers is responsible for managing its memory. | |
413 | * Zero-initialize every field you don't set up explicitly, to | |
8275c642 VW |
414 | * insulate against future API updates. After you submit a message |
415 | * and its transfers, ignore them until its completion callback. | |
8ae12a0d DB |
416 | */ |
417 | struct spi_transfer { | |
418 | /* it's ok if tx_buf == rx_buf (right?) | |
419 | * for MicroWire, one buffer must be null | |
0c868461 DB |
420 | * buffers must work with dma_*map_single() calls, unless |
421 | * spi_message.is_dma_mapped reports a pre-existing mapping | |
8ae12a0d DB |
422 | */ |
423 | const void *tx_buf; | |
424 | void *rx_buf; | |
425 | unsigned len; | |
426 | ||
427 | dma_addr_t tx_dma; | |
428 | dma_addr_t rx_dma; | |
429 | ||
430 | unsigned cs_change:1; | |
4cff33f9 | 431 | u8 bits_per_word; |
8ae12a0d | 432 | u16 delay_usecs; |
4cff33f9 | 433 | u32 speed_hz; |
8275c642 VW |
434 | |
435 | struct list_head transfer_list; | |
8ae12a0d DB |
436 | }; |
437 | ||
438 | /** | |
439 | * struct spi_message - one multi-segment SPI transaction | |
8275c642 | 440 | * @transfers: list of transfer segments in this transaction |
8ae12a0d DB |
441 | * @spi: SPI device to which the transaction is queued |
442 | * @is_dma_mapped: if true, the caller provided both dma and cpu virtual | |
443 | * addresses for each transfer buffer | |
444 | * @complete: called to report transaction completions | |
445 | * @context: the argument to complete() when it's called | |
b885244e DB |
446 | * @actual_length: the total number of bytes that were transferred in all |
447 | * successful segments | |
8ae12a0d DB |
448 | * @status: zero for success, else negative errno |
449 | * @queue: for use by whichever driver currently owns the message | |
450 | * @state: for use by whichever driver currently owns the message | |
0c868461 | 451 | * |
33e34dc6 | 452 | * A @spi_message is used to execute an atomic sequence of data transfers, |
8275c642 VW |
453 | * each represented by a struct spi_transfer. The sequence is "atomic" |
454 | * in the sense that no other spi_message may use that SPI bus until that | |
455 | * sequence completes. On some systems, many such sequences can execute as | |
456 | * as single programmed DMA transfer. On all systems, these messages are | |
457 | * queued, and might complete after transactions to other devices. Messages | |
458 | * sent to a given spi_device are alway executed in FIFO order. | |
459 | * | |
0c868461 DB |
460 | * The code that submits an spi_message (and its spi_transfers) |
461 | * to the lower layers is responsible for managing its memory. | |
462 | * Zero-initialize every field you don't set up explicitly, to | |
8275c642 VW |
463 | * insulate against future API updates. After you submit a message |
464 | * and its transfers, ignore them until its completion callback. | |
8ae12a0d DB |
465 | */ |
466 | struct spi_message { | |
747d844e | 467 | struct list_head transfers; |
8ae12a0d DB |
468 | |
469 | struct spi_device *spi; | |
470 | ||
471 | unsigned is_dma_mapped:1; | |
472 | ||
473 | /* REVISIT: we might want a flag affecting the behavior of the | |
474 | * last transfer ... allowing things like "read 16 bit length L" | |
475 | * immediately followed by "read L bytes". Basically imposing | |
476 | * a specific message scheduling algorithm. | |
477 | * | |
478 | * Some controller drivers (message-at-a-time queue processing) | |
479 | * could provide that as their default scheduling algorithm. But | |
b885244e | 480 | * others (with multi-message pipelines) could need a flag to |
8ae12a0d DB |
481 | * tell them about such special cases. |
482 | */ | |
483 | ||
484 | /* completion is reported through a callback */ | |
747d844e | 485 | void (*complete)(void *context); |
8ae12a0d DB |
486 | void *context; |
487 | unsigned actual_length; | |
488 | int status; | |
489 | ||
490 | /* for optional use by whatever driver currently owns the | |
491 | * spi_message ... between calls to spi_async and then later | |
492 | * complete(), that's the spi_master controller driver. | |
493 | */ | |
494 | struct list_head queue; | |
495 | void *state; | |
496 | }; | |
497 | ||
8275c642 VW |
498 | static inline void spi_message_init(struct spi_message *m) |
499 | { | |
500 | memset(m, 0, sizeof *m); | |
501 | INIT_LIST_HEAD(&m->transfers); | |
502 | } | |
503 | ||
504 | static inline void | |
505 | spi_message_add_tail(struct spi_transfer *t, struct spi_message *m) | |
506 | { | |
507 | list_add_tail(&t->transfer_list, &m->transfers); | |
508 | } | |
509 | ||
510 | static inline void | |
511 | spi_transfer_del(struct spi_transfer *t) | |
512 | { | |
513 | list_del(&t->transfer_list); | |
514 | } | |
515 | ||
0c868461 DB |
516 | /* It's fine to embed message and transaction structures in other data |
517 | * structures so long as you don't free them while they're in use. | |
518 | */ | |
519 | ||
520 | static inline struct spi_message *spi_message_alloc(unsigned ntrans, gfp_t flags) | |
521 | { | |
522 | struct spi_message *m; | |
523 | ||
524 | m = kzalloc(sizeof(struct spi_message) | |
525 | + ntrans * sizeof(struct spi_transfer), | |
526 | flags); | |
527 | if (m) { | |
8275c642 VW |
528 | int i; |
529 | struct spi_transfer *t = (struct spi_transfer *)(m + 1); | |
530 | ||
531 | INIT_LIST_HEAD(&m->transfers); | |
532 | for (i = 0; i < ntrans; i++, t++) | |
533 | spi_message_add_tail(t, m); | |
0c868461 DB |
534 | } |
535 | return m; | |
536 | } | |
537 | ||
538 | static inline void spi_message_free(struct spi_message *m) | |
539 | { | |
540 | kfree(m); | |
541 | } | |
542 | ||
7d077197 | 543 | extern int spi_setup(struct spi_device *spi); |
568d0697 | 544 | extern int spi_async(struct spi_device *spi, struct spi_message *message); |
8ae12a0d DB |
545 | |
546 | /*---------------------------------------------------------------------------*/ | |
547 | ||
548 | /* All these synchronous SPI transfer routines are utilities layered | |
549 | * over the core async transfer primitive. Here, "synchronous" means | |
550 | * they will sleep uninterruptibly until the async transfer completes. | |
551 | */ | |
552 | ||
553 | extern int spi_sync(struct spi_device *spi, struct spi_message *message); | |
554 | ||
555 | /** | |
556 | * spi_write - SPI synchronous write | |
557 | * @spi: device to which data will be written | |
558 | * @buf: data buffer | |
559 | * @len: data buffer size | |
33e34dc6 | 560 | * Context: can sleep |
8ae12a0d DB |
561 | * |
562 | * This writes the buffer and returns zero or a negative error code. | |
563 | * Callable only from contexts that can sleep. | |
564 | */ | |
565 | static inline int | |
566 | spi_write(struct spi_device *spi, const u8 *buf, size_t len) | |
567 | { | |
568 | struct spi_transfer t = { | |
569 | .tx_buf = buf, | |
8ae12a0d | 570 | .len = len, |
8ae12a0d | 571 | }; |
8275c642 | 572 | struct spi_message m; |
8ae12a0d | 573 | |
8275c642 VW |
574 | spi_message_init(&m); |
575 | spi_message_add_tail(&t, &m); | |
8ae12a0d DB |
576 | return spi_sync(spi, &m); |
577 | } | |
578 | ||
579 | /** | |
580 | * spi_read - SPI synchronous read | |
581 | * @spi: device from which data will be read | |
582 | * @buf: data buffer | |
583 | * @len: data buffer size | |
33e34dc6 | 584 | * Context: can sleep |
8ae12a0d | 585 | * |
33e34dc6 | 586 | * This reads the buffer and returns zero or a negative error code. |
8ae12a0d DB |
587 | * Callable only from contexts that can sleep. |
588 | */ | |
589 | static inline int | |
590 | spi_read(struct spi_device *spi, u8 *buf, size_t len) | |
591 | { | |
592 | struct spi_transfer t = { | |
8ae12a0d DB |
593 | .rx_buf = buf, |
594 | .len = len, | |
8ae12a0d | 595 | }; |
8275c642 | 596 | struct spi_message m; |
8ae12a0d | 597 | |
8275c642 VW |
598 | spi_message_init(&m); |
599 | spi_message_add_tail(&t, &m); | |
8ae12a0d DB |
600 | return spi_sync(spi, &m); |
601 | } | |
602 | ||
0c868461 | 603 | /* this copies txbuf and rxbuf data; for small transfers only! */ |
8ae12a0d DB |
604 | extern int spi_write_then_read(struct spi_device *spi, |
605 | const u8 *txbuf, unsigned n_tx, | |
606 | u8 *rxbuf, unsigned n_rx); | |
607 | ||
608 | /** | |
609 | * spi_w8r8 - SPI synchronous 8 bit write followed by 8 bit read | |
610 | * @spi: device with which data will be exchanged | |
611 | * @cmd: command to be written before data is read back | |
33e34dc6 | 612 | * Context: can sleep |
8ae12a0d DB |
613 | * |
614 | * This returns the (unsigned) eight bit number returned by the | |
615 | * device, or else a negative error code. Callable only from | |
616 | * contexts that can sleep. | |
617 | */ | |
618 | static inline ssize_t spi_w8r8(struct spi_device *spi, u8 cmd) | |
619 | { | |
620 | ssize_t status; | |
621 | u8 result; | |
622 | ||
623 | status = spi_write_then_read(spi, &cmd, 1, &result, 1); | |
624 | ||
625 | /* return negative errno or unsigned value */ | |
626 | return (status < 0) ? status : result; | |
627 | } | |
628 | ||
629 | /** | |
630 | * spi_w8r16 - SPI synchronous 8 bit write followed by 16 bit read | |
631 | * @spi: device with which data will be exchanged | |
632 | * @cmd: command to be written before data is read back | |
33e34dc6 | 633 | * Context: can sleep |
8ae12a0d DB |
634 | * |
635 | * This returns the (unsigned) sixteen bit number returned by the | |
636 | * device, or else a negative error code. Callable only from | |
637 | * contexts that can sleep. | |
638 | * | |
639 | * The number is returned in wire-order, which is at least sometimes | |
640 | * big-endian. | |
641 | */ | |
642 | static inline ssize_t spi_w8r16(struct spi_device *spi, u8 cmd) | |
643 | { | |
644 | ssize_t status; | |
645 | u16 result; | |
646 | ||
647 | status = spi_write_then_read(spi, &cmd, 1, (u8 *) &result, 2); | |
648 | ||
649 | /* return negative errno or unsigned value */ | |
650 | return (status < 0) ? status : result; | |
651 | } | |
652 | ||
653 | /*---------------------------------------------------------------------------*/ | |
654 | ||
655 | /* | |
656 | * INTERFACE between board init code and SPI infrastructure. | |
657 | * | |
658 | * No SPI driver ever sees these SPI device table segments, but | |
659 | * it's how the SPI core (or adapters that get hotplugged) grows | |
660 | * the driver model tree. | |
661 | * | |
662 | * As a rule, SPI devices can't be probed. Instead, board init code | |
663 | * provides a table listing the devices which are present, with enough | |
664 | * information to bind and set up the device's driver. There's basic | |
665 | * support for nonstatic configurations too; enough to handle adding | |
666 | * parport adapters, or microcontrollers acting as USB-to-SPI bridges. | |
667 | */ | |
668 | ||
2604288f DB |
669 | /** |
670 | * struct spi_board_info - board-specific template for a SPI device | |
671 | * @modalias: Initializes spi_device.modalias; identifies the driver. | |
672 | * @platform_data: Initializes spi_device.platform_data; the particular | |
673 | * data stored there is driver-specific. | |
674 | * @controller_data: Initializes spi_device.controller_data; some | |
675 | * controllers need hints about hardware setup, e.g. for DMA. | |
676 | * @irq: Initializes spi_device.irq; depends on how the board is wired. | |
677 | * @max_speed_hz: Initializes spi_device.max_speed_hz; based on limits | |
678 | * from the chip datasheet and board-specific signal quality issues. | |
679 | * @bus_num: Identifies which spi_master parents the spi_device; unused | |
680 | * by spi_new_device(), and otherwise depends on board wiring. | |
681 | * @chip_select: Initializes spi_device.chip_select; depends on how | |
682 | * the board is wired. | |
683 | * @mode: Initializes spi_device.mode; based on the chip datasheet, board | |
684 | * wiring (some devices support both 3WIRE and standard modes), and | |
685 | * possibly presence of an inverter in the chipselect path. | |
686 | * | |
687 | * When adding new SPI devices to the device tree, these structures serve | |
688 | * as a partial device template. They hold information which can't always | |
689 | * be determined by drivers. Information that probe() can establish (such | |
690 | * as the default transfer wordsize) is not included here. | |
691 | * | |
692 | * These structures are used in two places. Their primary role is to | |
693 | * be stored in tables of board-specific device descriptors, which are | |
694 | * declared early in board initialization and then used (much later) to | |
695 | * populate a controller's device tree after the that controller's driver | |
696 | * initializes. A secondary (and atypical) role is as a parameter to | |
697 | * spi_new_device() call, which happens after those controller drivers | |
698 | * are active in some dynamic board configuration models. | |
699 | */ | |
8ae12a0d DB |
700 | struct spi_board_info { |
701 | /* the device name and module name are coupled, like platform_bus; | |
702 | * "modalias" is normally the driver name. | |
703 | * | |
704 | * platform_data goes to spi_device.dev.platform_data, | |
b885244e | 705 | * controller_data goes to spi_device.controller_data, |
8ae12a0d DB |
706 | * irq is copied too |
707 | */ | |
75368bf6 | 708 | char modalias[SPI_NAME_SIZE]; |
8ae12a0d | 709 | const void *platform_data; |
b885244e | 710 | void *controller_data; |
8ae12a0d DB |
711 | int irq; |
712 | ||
713 | /* slower signaling on noisy or low voltage boards */ | |
714 | u32 max_speed_hz; | |
715 | ||
716 | ||
717 | /* bus_num is board specific and matches the bus_num of some | |
718 | * spi_master that will probably be registered later. | |
719 | * | |
720 | * chip_select reflects how this chip is wired to that master; | |
721 | * it's less than num_chipselect. | |
722 | */ | |
723 | u16 bus_num; | |
724 | u16 chip_select; | |
725 | ||
980a01c9 DB |
726 | /* mode becomes spi_device.mode, and is essential for chips |
727 | * where the default of SPI_CS_HIGH = 0 is wrong. | |
728 | */ | |
729 | u8 mode; | |
730 | ||
8ae12a0d DB |
731 | /* ... may need additional spi_device chip config data here. |
732 | * avoid stuff protocol drivers can set; but include stuff | |
733 | * needed to behave without being bound to a driver: | |
8ae12a0d DB |
734 | * - quirks like clock rate mattering when not selected |
735 | */ | |
736 | }; | |
737 | ||
738 | #ifdef CONFIG_SPI | |
739 | extern int | |
740 | spi_register_board_info(struct spi_board_info const *info, unsigned n); | |
741 | #else | |
742 | /* board init code may ignore whether SPI is configured or not */ | |
743 | static inline int | |
744 | spi_register_board_info(struct spi_board_info const *info, unsigned n) | |
745 | { return 0; } | |
746 | #endif | |
747 | ||
748 | ||
749 | /* If you're hotplugging an adapter with devices (parport, usb, etc) | |
0c868461 DB |
750 | * use spi_new_device() to describe each device. You can also call |
751 | * spi_unregister_device() to start making that device vanish, but | |
752 | * normally that would be handled by spi_unregister_master(). | |
dc87c98e GL |
753 | * |
754 | * You can also use spi_alloc_device() and spi_add_device() to use a two | |
755 | * stage registration sequence for each spi_device. This gives the caller | |
756 | * some more control over the spi_device structure before it is registered, | |
757 | * but requires that caller to initialize fields that would otherwise | |
758 | * be defined using the board info. | |
8ae12a0d | 759 | */ |
dc87c98e GL |
760 | extern struct spi_device * |
761 | spi_alloc_device(struct spi_master *master); | |
762 | ||
763 | extern int | |
764 | spi_add_device(struct spi_device *spi); | |
765 | ||
8ae12a0d DB |
766 | extern struct spi_device * |
767 | spi_new_device(struct spi_master *, struct spi_board_info *); | |
768 | ||
769 | static inline void | |
770 | spi_unregister_device(struct spi_device *spi) | |
771 | { | |
772 | if (spi) | |
773 | device_unregister(&spi->dev); | |
774 | } | |
775 | ||
75368bf6 AV |
776 | extern const struct spi_device_id * |
777 | spi_get_device_id(const struct spi_device *sdev); | |
778 | ||
8ae12a0d | 779 | #endif /* __LINUX_SPI_H */ |