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David Brownell8ae12a02006-01-08 13:34:19 -08001/*
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 Dunlap0a30c5c2009-01-04 12:00:47 -080022#include <linux/device.h>
Anton Vorontsov75368bf2009-09-22 16:46:04 -070023#include <linux/mod_devicetable.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090024#include <linux/slab.h>
Linus Walleijffbbdd212012-02-22 10:05:38 +010025#include <linux/kthread.h>
Mark Brownb1589352013-10-05 11:50:40 +010026#include <linux/completion.h>
Randy Dunlap0a30c5c2009-01-04 12:00:47 -080027
Mark Brown99adef32014-01-16 12:22:43 +000028struct dma_chan;
29
David Brownell8ae12a02006-01-08 13:34:19 -080030/*
David Brownellb8852442006-01-08 13:34:23 -080031 * INTERFACES between SPI master-side drivers and SPI infrastructure.
David Brownell8ae12a02006-01-08 13:34:19 -080032 * (There's no SPI slave support for Linux yet...)
David Brownell8ae12a02006-01-08 13:34:19 -080033 */
34extern struct bus_type spi_bus_type;
35
36/**
37 * struct spi_device - Master side proxy for an SPI slave device
38 * @dev: Driver model representation of the device.
39 * @master: SPI controller used with the device.
40 * @max_speed_hz: Maximum clock rate to be used with this chip
41 * (on this board); may be changed by the device's driver.
Imre Deak4cff33f2006-02-17 10:02:18 -080042 * The spi_transfer.speed_hz can override this for each transfer.
David Brownell33e34dc2007-05-08 00:32:21 -070043 * @chip_select: Chipselect, distinguishing chips handled by @master.
David Brownell8ae12a02006-01-08 13:34:19 -080044 * @mode: The spi mode defines how data is clocked out and in.
45 * This may be changed by the device's driver.
David Brownell33e34dc2007-05-08 00:32:21 -070046 * The "active low" default for chipselect mode can be overridden
47 * (by specifying SPI_CS_HIGH) as can the "MSB first" default for
48 * each word in a transfer (by specifying SPI_LSB_FIRST).
David Brownell8ae12a02006-01-08 13:34:19 -080049 * @bits_per_word: Data transfers involve one or more words; word sizes
David Brownell747d8442006-04-02 10:33:37 -080050 * like eight or 12 bits are common. In-memory wordsizes are
David Brownell8ae12a02006-01-08 13:34:19 -080051 * powers of two bytes (e.g. 20 bit samples use 32 bits).
David Brownellccf77cc2006-04-03 15:46:22 -070052 * This may be changed by the device's driver, or left at the
53 * default (0) indicating protocol words are eight bit bytes.
Imre Deak4cff33f2006-02-17 10:02:18 -080054 * The spi_transfer.bits_per_word can override this for each transfer.
David Brownell8ae12a02006-01-08 13:34:19 -080055 * @irq: Negative, or the number passed to request_irq() to receive
David Brownell747d8442006-04-02 10:33:37 -080056 * interrupts from this device.
David Brownell8ae12a02006-01-08 13:34:19 -080057 * @controller_state: Controller's runtime state
David Brownellb8852442006-01-08 13:34:23 -080058 * @controller_data: Board-specific definitions for controller, such as
David Brownell747d8442006-04-02 10:33:37 -080059 * FIFO initialization parameters; from board_info.controller_data
David Brownell33e34dc2007-05-08 00:32:21 -070060 * @modalias: Name of the driver to use with this device, or an alias
61 * for that name. This appears in the sysfs "modalias" attribute
62 * for driver coldplugging, and in uevents used for hotplugging
Andreas Larsson446411e2013-02-13 14:20:25 +010063 * @cs_gpio: gpio number of the chipselect line (optional, -ENOENT when
Andreas Larsson095c3752013-01-29 15:53:41 +010064 * when not using a GPIO line)
David Brownell8ae12a02006-01-08 13:34:19 -080065 *
David Brownell33e34dc2007-05-08 00:32:21 -070066 * A @spi_device is used to interchange data between an SPI slave
David Brownell8ae12a02006-01-08 13:34:19 -080067 * (usually a discrete chip) and CPU memory.
68 *
David Brownell33e34dc2007-05-08 00:32:21 -070069 * In @dev, the platform_data is used to hold information about this
David Brownell8ae12a02006-01-08 13:34:19 -080070 * device that's meaningful to the device's protocol driver, but not
71 * to its controller. One example might be an identifier for a chip
David Brownell33e34dc2007-05-08 00:32:21 -070072 * variant with slightly different functionality; another might be
73 * information about how this particular board wires the chip's pins.
David Brownell8ae12a02006-01-08 13:34:19 -080074 */
75struct spi_device {
76 struct device dev;
77 struct spi_master *master;
78 u32 max_speed_hz;
79 u8 chip_select;
Trent Piepho89c1f60742013-12-13 18:27:44 -080080 u8 bits_per_word;
wangyuhangf477b7f2013-08-11 18:15:17 +080081 u16 mode;
David Brownellb8852442006-01-08 13:34:23 -080082#define SPI_CPHA 0x01 /* clock phase */
83#define SPI_CPOL 0x02 /* clock polarity */
David Brownell0c868462006-01-08 13:34:25 -080084#define SPI_MODE_0 (0|0) /* (original MicroWire) */
85#define SPI_MODE_1 (0|SPI_CPHA)
David Brownell8ae12a02006-01-08 13:34:19 -080086#define SPI_MODE_2 (SPI_CPOL|0)
87#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
David Brownellb8852442006-01-08 13:34:23 -080088#define SPI_CS_HIGH 0x04 /* chipselect active high? */
David Brownellccf77cc2006-04-03 15:46:22 -070089#define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */
David Brownellc06e6772007-07-17 04:04:03 -070090#define SPI_3WIRE 0x10 /* SI/SO signals shared */
Anton Vorontsov4ef7af52007-07-31 00:38:43 -070091#define SPI_LOOP 0x20 /* loopback mode */
David Brownellb55f6272009-06-30 11:41:26 -070092#define SPI_NO_CS 0x40 /* 1 dev/bus, no chipselect */
93#define SPI_READY 0x80 /* slave pulls low to pause */
wangyuhangf477b7f2013-08-11 18:15:17 +080094#define SPI_TX_DUAL 0x100 /* transmit with 2 wires */
95#define SPI_TX_QUAD 0x200 /* transmit with 4 wires */
96#define SPI_RX_DUAL 0x400 /* receive with 2 wires */
97#define SPI_RX_QUAD 0x800 /* receive with 4 wires */
David Brownell8ae12a02006-01-08 13:34:19 -080098 int irq;
99 void *controller_state;
David Brownellb8852442006-01-08 13:34:23 -0800100 void *controller_data;
Anton Vorontsov75368bf2009-09-22 16:46:04 -0700101 char modalias[SPI_NAME_SIZE];
Jean-Christophe PLAGNIOL-VILLARD74317982012-11-15 20:19:57 +0100102 int cs_gpio; /* chip select gpio */
David Brownell8ae12a02006-01-08 13:34:19 -0800103
David Brownell33e34dc2007-05-08 00:32:21 -0700104 /*
105 * likely need more hooks for more protocol options affecting how
106 * the controller talks to each chip, like:
107 * - memory packing (12 bit samples into low bits, others zeroed)
108 * - priority
109 * - drop chipselect after each word
110 * - chipselect delays
111 * - ...
112 */
David Brownell8ae12a02006-01-08 13:34:19 -0800113};
114
115static inline struct spi_device *to_spi_device(struct device *dev)
116{
David Brownellb8852442006-01-08 13:34:23 -0800117 return dev ? container_of(dev, struct spi_device, dev) : NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800118}
119
120/* most drivers won't need to care about device refcounting */
121static inline struct spi_device *spi_dev_get(struct spi_device *spi)
122{
123 return (spi && get_device(&spi->dev)) ? spi : NULL;
124}
125
126static inline void spi_dev_put(struct spi_device *spi)
127{
128 if (spi)
129 put_device(&spi->dev);
130}
131
132/* ctldata is for the bus_master driver's runtime state */
133static inline void *spi_get_ctldata(struct spi_device *spi)
134{
135 return spi->controller_state;
136}
137
138static inline void spi_set_ctldata(struct spi_device *spi, void *state)
139{
140 spi->controller_state = state;
141}
142
Ben Dooks9b40ff42007-02-12 00:52:41 -0800143/* device driver data */
144
145static inline void spi_set_drvdata(struct spi_device *spi, void *data)
146{
147 dev_set_drvdata(&spi->dev, data);
148}
149
150static inline void *spi_get_drvdata(struct spi_device *spi)
151{
152 return dev_get_drvdata(&spi->dev);
153}
David Brownell8ae12a02006-01-08 13:34:19 -0800154
155struct spi_message;
Mark Brownb1589352013-10-05 11:50:40 +0100156struct spi_transfer;
David Brownellb8852442006-01-08 13:34:23 -0800157
David Brownell26042882007-07-31 00:39:44 -0700158/**
159 * struct spi_driver - Host side "protocol" driver
Anton Vorontsov75368bf2009-09-22 16:46:04 -0700160 * @id_table: List of SPI devices supported by this driver
David Brownell26042882007-07-31 00:39:44 -0700161 * @probe: Binds this driver to the spi device. Drivers can verify
162 * that the device is actually present, and may need to configure
163 * characteristics (such as bits_per_word) which weren't needed for
164 * the initial configuration done during system setup.
165 * @remove: Unbinds this driver from the spi device
166 * @shutdown: Standard shutdown callback used during system state
167 * transitions such as powerdown/halt and kexec
168 * @suspend: Standard suspend callback used during system state transitions
169 * @resume: Standard resume callback used during system state transitions
170 * @driver: SPI device drivers should initialize the name and owner
171 * field of this structure.
172 *
173 * This represents the kind of device driver that uses SPI messages to
174 * interact with the hardware at the other end of a SPI link. It's called
175 * a "protocol" driver because it works through messages rather than talking
176 * directly to SPI hardware (which is what the underlying SPI controller
177 * driver does to pass those messages). These protocols are defined in the
178 * specification for the device(s) supported by the driver.
179 *
180 * As a rule, those device protocols represent the lowest level interface
181 * supported by a driver, and it will support upper level interfaces too.
182 * Examples of such upper levels include frameworks like MTD, networking,
183 * MMC, RTC, filesystem character device nodes, and hardware monitoring.
184 */
David Brownellb8852442006-01-08 13:34:23 -0800185struct spi_driver {
Anton Vorontsov75368bf2009-09-22 16:46:04 -0700186 const struct spi_device_id *id_table;
David Brownellb8852442006-01-08 13:34:23 -0800187 int (*probe)(struct spi_device *spi);
188 int (*remove)(struct spi_device *spi);
189 void (*shutdown)(struct spi_device *spi);
190 int (*suspend)(struct spi_device *spi, pm_message_t mesg);
191 int (*resume)(struct spi_device *spi);
192 struct device_driver driver;
193};
194
195static inline struct spi_driver *to_spi_driver(struct device_driver *drv)
196{
197 return drv ? container_of(drv, struct spi_driver, driver) : NULL;
198}
199
200extern int spi_register_driver(struct spi_driver *sdrv);
201
David Brownell33e34dc2007-05-08 00:32:21 -0700202/**
203 * spi_unregister_driver - reverse effect of spi_register_driver
204 * @sdrv: the driver to unregister
205 * Context: can sleep
206 */
David Brownellb8852442006-01-08 13:34:23 -0800207static inline void spi_unregister_driver(struct spi_driver *sdrv)
208{
Ben Dooksddc1e972007-02-12 00:52:43 -0800209 if (sdrv)
210 driver_unregister(&sdrv->driver);
David Brownellb8852442006-01-08 13:34:23 -0800211}
212
Lars-Peter Clausen3acbb012011-11-16 10:13:37 +0100213/**
214 * module_spi_driver() - Helper macro for registering a SPI driver
215 * @__spi_driver: spi_driver struct
216 *
217 * Helper macro for SPI drivers which do not do anything special in module
218 * init/exit. This eliminates a lot of boilerplate. Each module may only
219 * use this macro once, and calling it replaces module_init() and module_exit()
220 */
221#define module_spi_driver(__spi_driver) \
222 module_driver(__spi_driver, spi_register_driver, \
223 spi_unregister_driver)
David Brownellb8852442006-01-08 13:34:23 -0800224
David Brownell8ae12a02006-01-08 13:34:19 -0800225/**
226 * struct spi_master - interface to SPI master controller
Tony Jones49dce682007-10-16 01:27:48 -0700227 * @dev: device interface to this driver
Feng Tang2b9603a2010-08-02 15:52:15 +0800228 * @list: link with the global spi_master list
David Brownell8ae12a02006-01-08 13:34:19 -0800229 * @bus_num: board-specific (and often SOC-specific) identifier for a
David Brownell747d8442006-04-02 10:33:37 -0800230 * given SPI controller.
David Brownellb8852442006-01-08 13:34:23 -0800231 * @num_chipselect: chipselects are used to distinguish individual
David Brownell747d8442006-04-02 10:33:37 -0800232 * SPI slaves, and are numbered from zero to num_chipselects.
233 * each slave has a chipselect signal, but it's common that not
234 * every chipselect is connected to a slave.
Mike Rapoportfd5e1912009-04-06 19:00:56 -0700235 * @dma_alignment: SPI controller constraint on DMA buffers alignment.
Randy Dunlapb73b2552009-09-22 16:46:00 -0700236 * @mode_bits: flags understood by this controller driver
Stephen Warren543bb252013-03-26 20:37:57 -0600237 * @bits_per_word_mask: A mask indicating which values of bits_per_word are
238 * supported by the driver. Bit n indicates that a bits_per_word n+1 is
239 * suported. If set, the SPI core will reject any transfer with an
240 * unsupported bits_per_word. If not set, this value is simply ignored,
241 * and it's up to the individual driver to perform any validation.
Mark Browna2fd4f92013-07-10 14:57:26 +0100242 * @min_speed_hz: Lowest supported transfer speed
243 * @max_speed_hz: Highest supported transfer speed
Randy Dunlapb73b2552009-09-22 16:46:00 -0700244 * @flags: other constraints relevant to this driver
Ernst Schwab5c79a5a2010-08-16 15:10:11 +0200245 * @bus_lock_spinlock: spinlock for SPI bus locking
246 * @bus_lock_mutex: mutex for SPI bus locking
247 * @bus_lock_flag: indicates that the SPI bus is locked for exclusive use
David Brownell8ae12a02006-01-08 13:34:19 -0800248 * @setup: updates the device mode and clocking records used by a
David Brownell80224562007-02-12 00:52:46 -0800249 * device's SPI controller; protocol code may call this. This
250 * must fail if an unrecognized or unsupported mode is requested.
David Brownell33e34dc2007-05-08 00:32:21 -0700251 * It's always safe to call this unless transfers are pending on
252 * the device whose settings are being modified.
David Brownell8ae12a02006-01-08 13:34:19 -0800253 * @transfer: adds a message to the controller's transfer queue.
254 * @cleanup: frees controller-specific state
Linus Walleijffbbdd212012-02-22 10:05:38 +0100255 * @queued: whether this master is providing an internal message queue
256 * @kworker: thread struct for message pump
257 * @kworker_task: pointer to task for message pump kworker thread
258 * @pump_messages: work struct for scheduling work to the message pump
259 * @queue_lock: spinlock to syncronise access to message queue
260 * @queue: message queue
261 * @cur_msg: the currently in-flight message
Mark Brown2841a5f2013-10-05 00:23:12 +0100262 * @cur_msg_prepared: spi_prepare_message was called for the currently
263 * in-flight message
Mark Brownb1589352013-10-05 11:50:40 +0100264 * @xfer_completion: used by core tranfer_one_message()
Linus Walleijffbbdd212012-02-22 10:05:38 +0100265 * @busy: message pump is busy
266 * @running: message pump is running
267 * @rt: whether this queue is set to run as a realtime task
Mark Brown49834de2013-07-28 14:47:02 +0100268 * @auto_runtime_pm: the core should ensure a runtime PM reference is held
269 * while the hardware is prepared, using the parent
270 * device for the spidev
Linus Walleijffbbdd212012-02-22 10:05:38 +0100271 * @prepare_transfer_hardware: a message will soon arrive from the queue
272 * so the subsystem requests the driver to prepare the transfer hardware
273 * by issuing this call
274 * @transfer_one_message: the subsystem calls the driver to transfer a single
275 * message while queuing transfers that arrive in the meantime. When the
276 * driver is finished with this message, it must call
277 * spi_finalize_current_message() so the subsystem can issue the next
278 * transfer
Randy Dunlapdbabe0d2012-04-17 17:03:50 -0700279 * @unprepare_transfer_hardware: there are currently no more messages on the
Linus Walleijffbbdd212012-02-22 10:05:38 +0100280 * queue so the subsystem notifies the driver that it may relax the
281 * hardware by issuing this call
Geert Uytterhoevenbd6857a2014-01-21 16:10:07 +0100282 * @set_cs: set the logic level of the chip select line. May be called
Mark Brownb1589352013-10-05 11:50:40 +0100283 * from interrupt context.
Mark Brown2841a5f2013-10-05 00:23:12 +0100284 * @prepare_message: set up the controller to transfer a single message,
285 * for example doing DMA mapping. Called from threaded
286 * context.
Geert Uytterhoeven05167122014-01-21 16:10:06 +0100287 * @transfer_one: transfer a single spi_transfer.
288 * - return 0 if the transfer is finished,
289 * - return 1 if the transfer is still in progress. When
290 * the driver is finished with this transfer it must
291 * call spi_finalize_current_transfer() so the subsystem
292 * can issue the next transfer
Mark Brown2841a5f2013-10-05 00:23:12 +0100293 * @unprepare_message: undo any work done by prepare_message().
Andreas Larsson095c3752013-01-29 15:53:41 +0100294 * @cs_gpios: Array of GPIOs to use as chip select lines; one per CS
Andreas Larsson446411e2013-02-13 14:20:25 +0100295 * number. Any individual value may be -ENOENT for CS lines that
Andreas Larsson095c3752013-01-29 15:53:41 +0100296 * are not GPIOs (driven by the SPI controller itself).
David Brownell8ae12a02006-01-08 13:34:19 -0800297 *
David Brownell33e34dc2007-05-08 00:32:21 -0700298 * Each SPI master controller can communicate with one or more @spi_device
David Brownell8ae12a02006-01-08 13:34:19 -0800299 * children. These make a small bus, sharing MOSI, MISO and SCK signals
300 * but not chip select signals. Each device may be configured to use a
301 * different clock rate, since those shared signals are ignored unless
302 * the chip is selected.
303 *
304 * The driver for an SPI controller manages access to those devices through
David Brownell33e34dc2007-05-08 00:32:21 -0700305 * a queue of spi_message transactions, copying data between CPU memory and
306 * an SPI slave device. For each such message it queues, it calls the
David Brownell8ae12a02006-01-08 13:34:19 -0800307 * message's completion function when the transaction completes.
308 */
309struct spi_master {
Tony Jones49dce682007-10-16 01:27:48 -0700310 struct device dev;
David Brownell8ae12a02006-01-08 13:34:19 -0800311
Feng Tang2b9603a2010-08-02 15:52:15 +0800312 struct list_head list;
313
David Brownella020ed72006-04-03 15:49:04 -0700314 /* other than negative (== assign one dynamically), bus_num is fully
David Brownell8ae12a02006-01-08 13:34:19 -0800315 * board-specific. usually that simplifies to being SOC-specific.
David Brownella020ed72006-04-03 15:49:04 -0700316 * example: one SOC has three SPI controllers, numbered 0..2,
David Brownell8ae12a02006-01-08 13:34:19 -0800317 * and one board's schematics might show it using SPI-2. software
318 * would normally use bus_num=2 for that controller.
319 */
David Brownella020ed72006-04-03 15:49:04 -0700320 s16 bus_num;
David Brownell8ae12a02006-01-08 13:34:19 -0800321
322 /* chipselects will be integral to many controllers; some others
323 * might use board-specific GPIOs.
324 */
325 u16 num_chipselect;
326
Mike Rapoportfd5e1912009-04-06 19:00:56 -0700327 /* some SPI controllers pose alignment requirements on DMAable
328 * buffers; let protocol drivers know about these requirements.
329 */
330 u16 dma_alignment;
331
David Brownelle7db06b2009-06-17 16:26:04 -0700332 /* spi_device.mode flags understood by this controller driver */
333 u16 mode_bits;
334
Stephen Warren543bb252013-03-26 20:37:57 -0600335 /* bitmask of supported bits_per_word for transfers */
336 u32 bits_per_word_mask;
Stephen Warren2922a8d2013-05-21 20:36:34 -0600337#define SPI_BPW_MASK(bits) BIT((bits) - 1)
Stephen Warrenb6aa23c2013-08-01 16:08:57 -0600338#define SPI_BIT_MASK(bits) (((bits) == 32) ? ~0U : (BIT(bits) - 1))
Stephen Warreneca89602013-05-30 09:59:40 -0600339#define SPI_BPW_RANGE_MASK(min, max) (SPI_BIT_MASK(max) - SPI_BIT_MASK(min - 1))
Stephen Warren543bb252013-03-26 20:37:57 -0600340
Mark Browna2fd4f92013-07-10 14:57:26 +0100341 /* limits on transfer speed */
342 u32 min_speed_hz;
343 u32 max_speed_hz;
344
David Brownell70d60272009-06-30 11:41:27 -0700345 /* other constraints relevant to this driver */
346 u16 flags;
347#define SPI_MASTER_HALF_DUPLEX BIT(0) /* can't do full duplex */
David Brownell568d0692009-09-22 16:46:18 -0700348#define SPI_MASTER_NO_RX BIT(1) /* can't do buffer read */
349#define SPI_MASTER_NO_TX BIT(2) /* can't do buffer write */
David Brownell70d60272009-06-30 11:41:27 -0700350
Ernst Schwabcf32b712010-06-28 17:49:29 -0700351 /* lock and mutex for SPI bus locking */
352 spinlock_t bus_lock_spinlock;
353 struct mutex bus_lock_mutex;
354
355 /* flag indicating that the SPI bus is locked for exclusive use */
356 bool bus_lock_flag;
357
David Brownell6e538aa2009-04-21 12:24:49 -0700358 /* Setup mode and clock, etc (spi driver may call many times).
359 *
360 * IMPORTANT: this may be called when transfers to another
361 * device are active. DO NOT UPDATE SHARED REGISTERS in ways
362 * which could break those transfers.
363 */
David Brownell8ae12a02006-01-08 13:34:19 -0800364 int (*setup)(struct spi_device *spi);
365
366 /* bidirectional bulk transfers
367 *
368 * + The transfer() method may not sleep; its main role is
369 * just to add the message to the queue.
370 * + For now there's no remove-from-queue operation, or
371 * any other request management
372 * + To a given spi_device, message queueing is pure fifo
373 *
374 * + The master's main job is to process its message queue,
375 * selecting a chip then transferring data
376 * + If there are multiple spi_device children, the i/o queue
377 * arbitration algorithm is unspecified (round robin, fifo,
378 * priority, reservations, preemption, etc)
379 *
380 * + Chipselect stays active during the entire message
381 * (unless modified by spi_transfer.cs_change != 0).
382 * + The message transfers use clock and SPI mode parameters
383 * previously established by setup() for this device
384 */
385 int (*transfer)(struct spi_device *spi,
386 struct spi_message *mesg);
387
388 /* called on release() to free memory provided by spi_master */
Hans-Peter Nilsson0ffa0282007-02-12 00:52:45 -0800389 void (*cleanup)(struct spi_device *spi);
Linus Walleijffbbdd212012-02-22 10:05:38 +0100390
391 /*
Mark Brown99adef32014-01-16 12:22:43 +0000392 * Used to enable core support for DMA handling, if can_dma()
393 * exists and returns true then the transfer will be mapped
394 * prior to transfer_one() being called. The driver should
395 * not modify or store xfer and dma_tx and dma_rx must be set
396 * while the device is prepared.
397 */
398 bool (*can_dma)(struct spi_master *master,
399 struct spi_device *spi,
400 struct spi_transfer *xfer);
401
402 /*
Linus Walleijffbbdd212012-02-22 10:05:38 +0100403 * These hooks are for drivers that want to use the generic
404 * master transfer queueing mechanism. If these are used, the
405 * transfer() function above must NOT be specified by the driver.
406 * Over time we expect SPI drivers to be phased over to this API.
407 */
408 bool queued;
409 struct kthread_worker kworker;
410 struct task_struct *kworker_task;
411 struct kthread_work pump_messages;
412 spinlock_t queue_lock;
413 struct list_head queue;
414 struct spi_message *cur_msg;
415 bool busy;
416 bool running;
417 bool rt;
Mark Brown49834de2013-07-28 14:47:02 +0100418 bool auto_runtime_pm;
Mark Brown2841a5f2013-10-05 00:23:12 +0100419 bool cur_msg_prepared;
Mark Brown99adef32014-01-16 12:22:43 +0000420 bool cur_msg_mapped;
Mark Brownb1589352013-10-05 11:50:40 +0100421 struct completion xfer_completion;
Linus Walleijffbbdd212012-02-22 10:05:38 +0100422
423 int (*prepare_transfer_hardware)(struct spi_master *master);
424 int (*transfer_one_message)(struct spi_master *master,
425 struct spi_message *mesg);
426 int (*unprepare_transfer_hardware)(struct spi_master *master);
Mark Brown2841a5f2013-10-05 00:23:12 +0100427 int (*prepare_message)(struct spi_master *master,
428 struct spi_message *message);
429 int (*unprepare_message)(struct spi_master *master,
430 struct spi_message *message);
Mark Brown49834de2013-07-28 14:47:02 +0100431
Mark Brownb1589352013-10-05 11:50:40 +0100432 /*
433 * These hooks are for drivers that use a generic implementation
434 * of transfer_one_message() provied by the core.
435 */
436 void (*set_cs)(struct spi_device *spi, bool enable);
437 int (*transfer_one)(struct spi_master *master, struct spi_device *spi,
438 struct spi_transfer *transfer);
439
Jean-Christophe PLAGNIOL-VILLARD74317982012-11-15 20:19:57 +0100440 /* gpio chip select */
441 int *cs_gpios;
Mark Brown99adef32014-01-16 12:22:43 +0000442
443 /* DMA channels for use with core dmaengine helpers */
444 struct dma_chan *dma_tx;
445 struct dma_chan *dma_rx;
David Brownell8ae12a02006-01-08 13:34:19 -0800446};
447
David Brownell0c868462006-01-08 13:34:25 -0800448static inline void *spi_master_get_devdata(struct spi_master *master)
449{
Tony Jones49dce682007-10-16 01:27:48 -0700450 return dev_get_drvdata(&master->dev);
David Brownell0c868462006-01-08 13:34:25 -0800451}
452
453static inline void spi_master_set_devdata(struct spi_master *master, void *data)
454{
Tony Jones49dce682007-10-16 01:27:48 -0700455 dev_set_drvdata(&master->dev, data);
David Brownell0c868462006-01-08 13:34:25 -0800456}
457
458static inline struct spi_master *spi_master_get(struct spi_master *master)
459{
Tony Jones49dce682007-10-16 01:27:48 -0700460 if (!master || !get_device(&master->dev))
David Brownell0c868462006-01-08 13:34:25 -0800461 return NULL;
462 return master;
463}
464
465static inline void spi_master_put(struct spi_master *master)
466{
467 if (master)
Tony Jones49dce682007-10-16 01:27:48 -0700468 put_device(&master->dev);
David Brownell0c868462006-01-08 13:34:25 -0800469}
470
Linus Walleijffbbdd212012-02-22 10:05:38 +0100471/* PM calls that need to be issued by the driver */
472extern int spi_master_suspend(struct spi_master *master);
473extern int spi_master_resume(struct spi_master *master);
474
475/* Calls the driver make to interact with the message queue */
476extern struct spi_message *spi_get_next_queued_message(struct spi_master *master);
477extern void spi_finalize_current_message(struct spi_master *master);
Mark Brownb1589352013-10-05 11:50:40 +0100478extern void spi_finalize_current_transfer(struct spi_master *master);
David Brownell0c868462006-01-08 13:34:25 -0800479
David Brownell8ae12a02006-01-08 13:34:19 -0800480/* the spi driver core manages memory for the spi_master classdev */
481extern struct spi_master *
482spi_alloc_master(struct device *host, unsigned size);
483
484extern int spi_register_master(struct spi_master *master);
Mark Brown666d5b42013-08-31 18:50:52 +0100485extern int devm_spi_register_master(struct device *dev,
486 struct spi_master *master);
David Brownell8ae12a02006-01-08 13:34:19 -0800487extern void spi_unregister_master(struct spi_master *master);
488
489extern struct spi_master *spi_busnum_to_master(u16 busnum);
490
491/*---------------------------------------------------------------------------*/
492
493/*
494 * I/O INTERFACE between SPI controller and protocol drivers
495 *
496 * Protocol drivers use a queue of spi_messages, each transferring data
497 * between the controller and memory buffers.
498 *
499 * The spi_messages themselves consist of a series of read+write transfer
500 * segments. Those segments always read the same number of bits as they
501 * write; but one or the other is easily ignored by passing a null buffer
502 * pointer. (This is unlike most types of I/O API, because SPI hardware
503 * is full duplex.)
504 *
505 * NOTE: Allocation of spi_transfer and spi_message memory is entirely
506 * up to the protocol driver, which guarantees the integrity of both (as
507 * well as the data buffers) for as long as the message is queued.
508 */
509
510/**
511 * struct spi_transfer - a read/write buffer pair
Vitaly Wool8275c642006-01-08 13:34:28 -0800512 * @tx_buf: data to be written (dma-safe memory), or NULL
513 * @rx_buf: data to be read (dma-safe memory), or NULL
David Brownell33e34dc2007-05-08 00:32:21 -0700514 * @tx_dma: DMA address of tx_buf, if @spi_message.is_dma_mapped
515 * @rx_dma: DMA address of rx_buf, if @spi_message.is_dma_mapped
wangyuhangf477b7f2013-08-11 18:15:17 +0800516 * @tx_nbits: number of bits used for writting. If 0 the default
517 * (SPI_NBITS_SINGLE) is used.
518 * @rx_nbits: number of bits used for reading. If 0 the default
519 * (SPI_NBITS_SINGLE) is used.
David Brownell8ae12a02006-01-08 13:34:19 -0800520 * @len: size of rx and tx buffers (in bytes)
Frederik Schwarzer025dfda2008-10-16 19:02:37 +0200521 * @speed_hz: Select a speed other than the device default for this
David Brownell33e34dc2007-05-08 00:32:21 -0700522 * transfer. If 0 the default (from @spi_device) is used.
Frederik Schwarzer025dfda2008-10-16 19:02:37 +0200523 * @bits_per_word: select a bits_per_word other than the device default
David Brownell33e34dc2007-05-08 00:32:21 -0700524 * for this transfer. If 0 the default (from @spi_device) is used.
David Brownell8ae12a02006-01-08 13:34:19 -0800525 * @cs_change: affects chipselect after this transfer completes
526 * @delay_usecs: microseconds to delay after this transfer before
David Brownell747d8442006-04-02 10:33:37 -0800527 * (optionally) changing the chipselect status, then starting
David Brownell33e34dc2007-05-08 00:32:21 -0700528 * the next transfer or completing this @spi_message.
529 * @transfer_list: transfers are sequenced through @spi_message.transfers
David Brownell8ae12a02006-01-08 13:34:19 -0800530 *
531 * SPI transfers always write the same number of bytes as they read.
David Brownell33e34dc2007-05-08 00:32:21 -0700532 * Protocol drivers should always provide @rx_buf and/or @tx_buf.
David Brownell8ae12a02006-01-08 13:34:19 -0800533 * In some cases, they may also want to provide DMA addresses for
534 * the data being transferred; that may reduce overhead, when the
535 * underlying driver uses dma.
536 *
David Brownell4b1badf2006-12-29 16:48:39 -0800537 * If the transmit buffer is null, zeroes will be shifted out
David Brownell33e34dc2007-05-08 00:32:21 -0700538 * while filling @rx_buf. If the receive buffer is null, the data
Vitaly Wool8275c642006-01-08 13:34:28 -0800539 * shifted in will be discarded. Only "len" bytes shift out (or in).
540 * It's an error to try to shift out a partial word. (For example, by
541 * shifting out three bytes with word size of sixteen or twenty bits;
542 * the former uses two bytes per word, the latter uses four bytes.)
543 *
David Brownell80224562007-02-12 00:52:46 -0800544 * In-memory data values are always in native CPU byte order, translated
545 * from the wire byte order (big-endian except with SPI_LSB_FIRST). So
546 * for example when bits_per_word is sixteen, buffers are 2N bytes long
David Brownell33e34dc2007-05-08 00:32:21 -0700547 * (@len = 2N) and hold N sixteen bit words in CPU byte order.
David Brownell80224562007-02-12 00:52:46 -0800548 *
549 * When the word size of the SPI transfer is not a power-of-two multiple
550 * of eight bits, those in-memory words include extra bits. In-memory
551 * words are always seen by protocol drivers as right-justified, so the
552 * undefined (rx) or unused (tx) bits are always the most significant bits.
553 *
Vitaly Wool8275c642006-01-08 13:34:28 -0800554 * All SPI transfers start with the relevant chipselect active. Normally
555 * it stays selected until after the last transfer in a message. Drivers
David Brownell33e34dc2007-05-08 00:32:21 -0700556 * can affect the chipselect signal using cs_change.
David Brownell8ae12a02006-01-08 13:34:19 -0800557 *
558 * (i) If the transfer isn't the last one in the message, this flag is
559 * used to make the chipselect briefly go inactive in the middle of the
560 * message. Toggling chipselect in this way may be needed to terminate
561 * a chip command, letting a single spi_message perform all of group of
562 * chip transactions together.
563 *
564 * (ii) When the transfer is the last one in the message, the chip may
David Brownellf5a9c772007-06-16 10:16:08 -0700565 * stay selected until the next transfer. On multi-device SPI busses
566 * with nothing blocking messages going to other devices, this is just
567 * a performance hint; starting a message to another device deselects
568 * this one. But in other cases, this can be used to ensure correctness.
569 * Some devices need protocol transactions to be built from a series of
570 * spi_message submissions, where the content of one message is determined
571 * by the results of previous messages and where the whole transaction
572 * ends when the chipselect goes intactive.
David Brownell0c868462006-01-08 13:34:25 -0800573 *
wangyuhangf477b7f2013-08-11 18:15:17 +0800574 * When SPI can transfer in 1x,2x or 4x. It can get this tranfer information
575 * from device through @tx_nbits and @rx_nbits. In Bi-direction, these
576 * two should both be set. User can set transfer mode with SPI_NBITS_SINGLE(1x)
577 * SPI_NBITS_DUAL(2x) and SPI_NBITS_QUAD(4x) to support these three transfer.
578 *
David Brownell0c868462006-01-08 13:34:25 -0800579 * The code that submits an spi_message (and its spi_transfers)
580 * to the lower layers is responsible for managing its memory.
581 * Zero-initialize every field you don't set up explicitly, to
Vitaly Wool8275c642006-01-08 13:34:28 -0800582 * insulate against future API updates. After you submit a message
583 * and its transfers, ignore them until its completion callback.
David Brownell8ae12a02006-01-08 13:34:19 -0800584 */
585struct spi_transfer {
586 /* it's ok if tx_buf == rx_buf (right?)
587 * for MicroWire, one buffer must be null
David Brownell0c868462006-01-08 13:34:25 -0800588 * buffers must work with dma_*map_single() calls, unless
589 * spi_message.is_dma_mapped reports a pre-existing mapping
David Brownell8ae12a02006-01-08 13:34:19 -0800590 */
591 const void *tx_buf;
592 void *rx_buf;
593 unsigned len;
594
595 dma_addr_t tx_dma;
596 dma_addr_t rx_dma;
597
598 unsigned cs_change:1;
Mark Brownd3fbd452014-01-10 17:09:53 +0000599 unsigned tx_nbits:3;
600 unsigned rx_nbits:3;
wangyuhangf477b7f2013-08-11 18:15:17 +0800601#define SPI_NBITS_SINGLE 0x01 /* 1bit transfer */
602#define SPI_NBITS_DUAL 0x02 /* 2bits transfer */
603#define SPI_NBITS_QUAD 0x04 /* 4bits transfer */
Imre Deak4cff33f2006-02-17 10:02:18 -0800604 u8 bits_per_word;
David Brownell8ae12a02006-01-08 13:34:19 -0800605 u16 delay_usecs;
Imre Deak4cff33f2006-02-17 10:02:18 -0800606 u32 speed_hz;
Vitaly Wool8275c642006-01-08 13:34:28 -0800607
608 struct list_head transfer_list;
David Brownell8ae12a02006-01-08 13:34:19 -0800609};
610
611/**
612 * struct spi_message - one multi-segment SPI transaction
Vitaly Wool8275c642006-01-08 13:34:28 -0800613 * @transfers: list of transfer segments in this transaction
David Brownell8ae12a02006-01-08 13:34:19 -0800614 * @spi: SPI device to which the transaction is queued
615 * @is_dma_mapped: if true, the caller provided both dma and cpu virtual
616 * addresses for each transfer buffer
617 * @complete: called to report transaction completions
618 * @context: the argument to complete() when it's called
David Brownellb8852442006-01-08 13:34:23 -0800619 * @actual_length: the total number of bytes that were transferred in all
620 * successful segments
David Brownell8ae12a02006-01-08 13:34:19 -0800621 * @status: zero for success, else negative errno
622 * @queue: for use by whichever driver currently owns the message
623 * @state: for use by whichever driver currently owns the message
David Brownell0c868462006-01-08 13:34:25 -0800624 *
David Brownell33e34dc2007-05-08 00:32:21 -0700625 * A @spi_message is used to execute an atomic sequence of data transfers,
Vitaly Wool8275c642006-01-08 13:34:28 -0800626 * each represented by a struct spi_transfer. The sequence is "atomic"
627 * in the sense that no other spi_message may use that SPI bus until that
628 * sequence completes. On some systems, many such sequences can execute as
629 * as single programmed DMA transfer. On all systems, these messages are
630 * queued, and might complete after transactions to other devices. Messages
631 * sent to a given spi_device are alway executed in FIFO order.
632 *
David Brownell0c868462006-01-08 13:34:25 -0800633 * The code that submits an spi_message (and its spi_transfers)
634 * to the lower layers is responsible for managing its memory.
635 * Zero-initialize every field you don't set up explicitly, to
Vitaly Wool8275c642006-01-08 13:34:28 -0800636 * insulate against future API updates. After you submit a message
637 * and its transfers, ignore them until its completion callback.
David Brownell8ae12a02006-01-08 13:34:19 -0800638 */
639struct spi_message {
David Brownell747d8442006-04-02 10:33:37 -0800640 struct list_head transfers;
David Brownell8ae12a02006-01-08 13:34:19 -0800641
642 struct spi_device *spi;
643
644 unsigned is_dma_mapped:1;
645
646 /* REVISIT: we might want a flag affecting the behavior of the
647 * last transfer ... allowing things like "read 16 bit length L"
648 * immediately followed by "read L bytes". Basically imposing
649 * a specific message scheduling algorithm.
650 *
651 * Some controller drivers (message-at-a-time queue processing)
652 * could provide that as their default scheduling algorithm. But
David Brownellb8852442006-01-08 13:34:23 -0800653 * others (with multi-message pipelines) could need a flag to
David Brownell8ae12a02006-01-08 13:34:19 -0800654 * tell them about such special cases.
655 */
656
657 /* completion is reported through a callback */
David Brownell747d8442006-04-02 10:33:37 -0800658 void (*complete)(void *context);
David Brownell8ae12a02006-01-08 13:34:19 -0800659 void *context;
Sourav Poddar078726c2013-07-18 15:31:25 +0530660 unsigned frame_length;
David Brownell8ae12a02006-01-08 13:34:19 -0800661 unsigned actual_length;
662 int status;
663
664 /* for optional use by whatever driver currently owns the
665 * spi_message ... between calls to spi_async and then later
666 * complete(), that's the spi_master controller driver.
667 */
668 struct list_head queue;
669 void *state;
670};
671
Vitaly Wool8275c642006-01-08 13:34:28 -0800672static inline void spi_message_init(struct spi_message *m)
673{
674 memset(m, 0, sizeof *m);
675 INIT_LIST_HEAD(&m->transfers);
676}
677
678static inline void
679spi_message_add_tail(struct spi_transfer *t, struct spi_message *m)
680{
681 list_add_tail(&t->transfer_list, &m->transfers);
682}
683
684static inline void
685spi_transfer_del(struct spi_transfer *t)
686{
687 list_del(&t->transfer_list);
688}
689
Lars-Peter Clausen6d9eecd2013-01-09 17:31:00 +0000690/**
691 * spi_message_init_with_transfers - Initialize spi_message and append transfers
692 * @m: spi_message to be initialized
693 * @xfers: An array of spi transfers
694 * @num_xfers: Number of items in the xfer array
695 *
696 * This function initializes the given spi_message and adds each spi_transfer in
697 * the given array to the message.
698 */
699static inline void
700spi_message_init_with_transfers(struct spi_message *m,
701struct spi_transfer *xfers, unsigned int num_xfers)
702{
703 unsigned int i;
704
705 spi_message_init(m);
706 for (i = 0; i < num_xfers; ++i)
707 spi_message_add_tail(&xfers[i], m);
708}
709
David Brownell0c868462006-01-08 13:34:25 -0800710/* It's fine to embed message and transaction structures in other data
711 * structures so long as you don't free them while they're in use.
712 */
713
714static inline struct spi_message *spi_message_alloc(unsigned ntrans, gfp_t flags)
715{
716 struct spi_message *m;
717
718 m = kzalloc(sizeof(struct spi_message)
719 + ntrans * sizeof(struct spi_transfer),
720 flags);
721 if (m) {
Shubhrajyoti D8f536022012-02-27 19:29:05 +0530722 unsigned i;
Vitaly Wool8275c642006-01-08 13:34:28 -0800723 struct spi_transfer *t = (struct spi_transfer *)(m + 1);
724
725 INIT_LIST_HEAD(&m->transfers);
726 for (i = 0; i < ntrans; i++, t++)
727 spi_message_add_tail(t, m);
David Brownell0c868462006-01-08 13:34:25 -0800728 }
729 return m;
730}
731
732static inline void spi_message_free(struct spi_message *m)
733{
734 kfree(m);
735}
736
David Brownell7d077192009-06-17 16:26:03 -0700737extern int spi_setup(struct spi_device *spi);
David Brownell568d0692009-09-22 16:46:18 -0700738extern int spi_async(struct spi_device *spi, struct spi_message *message);
Ernst Schwabcf32b712010-06-28 17:49:29 -0700739extern int spi_async_locked(struct spi_device *spi,
740 struct spi_message *message);
David Brownell8ae12a02006-01-08 13:34:19 -0800741
742/*---------------------------------------------------------------------------*/
743
744/* All these synchronous SPI transfer routines are utilities layered
745 * over the core async transfer primitive. Here, "synchronous" means
746 * they will sleep uninterruptibly until the async transfer completes.
747 */
748
749extern int spi_sync(struct spi_device *spi, struct spi_message *message);
Ernst Schwabcf32b712010-06-28 17:49:29 -0700750extern int spi_sync_locked(struct spi_device *spi, struct spi_message *message);
751extern int spi_bus_lock(struct spi_master *master);
752extern int spi_bus_unlock(struct spi_master *master);
David Brownell8ae12a02006-01-08 13:34:19 -0800753
754/**
755 * spi_write - SPI synchronous write
756 * @spi: device to which data will be written
757 * @buf: data buffer
758 * @len: data buffer size
David Brownell33e34dc2007-05-08 00:32:21 -0700759 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800760 *
761 * This writes the buffer and returns zero or a negative error code.
762 * Callable only from contexts that can sleep.
763 */
764static inline int
Mark Brown0c4a1592011-05-11 00:09:30 +0200765spi_write(struct spi_device *spi, const void *buf, size_t len)
David Brownell8ae12a02006-01-08 13:34:19 -0800766{
767 struct spi_transfer t = {
768 .tx_buf = buf,
David Brownell8ae12a02006-01-08 13:34:19 -0800769 .len = len,
David Brownell8ae12a02006-01-08 13:34:19 -0800770 };
Vitaly Wool8275c642006-01-08 13:34:28 -0800771 struct spi_message m;
David Brownell8ae12a02006-01-08 13:34:19 -0800772
Vitaly Wool8275c642006-01-08 13:34:28 -0800773 spi_message_init(&m);
774 spi_message_add_tail(&t, &m);
David Brownell8ae12a02006-01-08 13:34:19 -0800775 return spi_sync(spi, &m);
776}
777
778/**
779 * spi_read - SPI synchronous read
780 * @spi: device from which data will be read
781 * @buf: data buffer
782 * @len: data buffer size
David Brownell33e34dc2007-05-08 00:32:21 -0700783 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800784 *
David Brownell33e34dc2007-05-08 00:32:21 -0700785 * This reads the buffer and returns zero or a negative error code.
David Brownell8ae12a02006-01-08 13:34:19 -0800786 * Callable only from contexts that can sleep.
787 */
788static inline int
Mark Brown0c4a1592011-05-11 00:09:30 +0200789spi_read(struct spi_device *spi, void *buf, size_t len)
David Brownell8ae12a02006-01-08 13:34:19 -0800790{
791 struct spi_transfer t = {
David Brownell8ae12a02006-01-08 13:34:19 -0800792 .rx_buf = buf,
793 .len = len,
David Brownell8ae12a02006-01-08 13:34:19 -0800794 };
Vitaly Wool8275c642006-01-08 13:34:28 -0800795 struct spi_message m;
David Brownell8ae12a02006-01-08 13:34:19 -0800796
Vitaly Wool8275c642006-01-08 13:34:28 -0800797 spi_message_init(&m);
798 spi_message_add_tail(&t, &m);
David Brownell8ae12a02006-01-08 13:34:19 -0800799 return spi_sync(spi, &m);
800}
801
Lars-Peter Clausen6d9eecd2013-01-09 17:31:00 +0000802/**
803 * spi_sync_transfer - synchronous SPI data transfer
804 * @spi: device with which data will be exchanged
805 * @xfers: An array of spi_transfers
806 * @num_xfers: Number of items in the xfer array
807 * Context: can sleep
808 *
809 * Does a synchronous SPI data transfer of the given spi_transfer array.
810 *
811 * For more specific semantics see spi_sync().
812 *
813 * It returns zero on success, else a negative error code.
814 */
815static inline int
816spi_sync_transfer(struct spi_device *spi, struct spi_transfer *xfers,
817 unsigned int num_xfers)
818{
819 struct spi_message msg;
820
821 spi_message_init_with_transfers(&msg, xfers, num_xfers);
822
823 return spi_sync(spi, &msg);
824}
825
David Brownell0c868462006-01-08 13:34:25 -0800826/* this copies txbuf and rxbuf data; for small transfers only! */
David Brownell8ae12a02006-01-08 13:34:19 -0800827extern int spi_write_then_read(struct spi_device *spi,
Mark Brown0c4a1592011-05-11 00:09:30 +0200828 const void *txbuf, unsigned n_tx,
829 void *rxbuf, unsigned n_rx);
David Brownell8ae12a02006-01-08 13:34:19 -0800830
831/**
832 * spi_w8r8 - SPI synchronous 8 bit write followed by 8 bit read
833 * @spi: device with which data will be exchanged
834 * @cmd: command to be written before data is read back
David Brownell33e34dc2007-05-08 00:32:21 -0700835 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800836 *
837 * This returns the (unsigned) eight bit number returned by the
838 * device, or else a negative error code. Callable only from
839 * contexts that can sleep.
840 */
841static inline ssize_t spi_w8r8(struct spi_device *spi, u8 cmd)
842{
843 ssize_t status;
844 u8 result;
845
846 status = spi_write_then_read(spi, &cmd, 1, &result, 1);
847
848 /* return negative errno or unsigned value */
849 return (status < 0) ? status : result;
850}
851
852/**
853 * spi_w8r16 - SPI synchronous 8 bit write followed by 16 bit read
854 * @spi: device with which data will be exchanged
855 * @cmd: command to be written before data is read back
David Brownell33e34dc2007-05-08 00:32:21 -0700856 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800857 *
858 * This returns the (unsigned) sixteen bit number returned by the
859 * device, or else a negative error code. Callable only from
860 * contexts that can sleep.
861 *
862 * The number is returned in wire-order, which is at least sometimes
863 * big-endian.
864 */
865static inline ssize_t spi_w8r16(struct spi_device *spi, u8 cmd)
866{
867 ssize_t status;
868 u16 result;
869
Geert Uytterhoeven269ccca2014-01-12 13:59:06 +0100870 status = spi_write_then_read(spi, &cmd, 1, &result, 2);
David Brownell8ae12a02006-01-08 13:34:19 -0800871
872 /* return negative errno or unsigned value */
873 return (status < 0) ? status : result;
874}
875
Lars-Peter Clausen05071aa2013-09-27 16:34:27 +0200876/**
877 * spi_w8r16be - SPI synchronous 8 bit write followed by 16 bit big-endian read
878 * @spi: device with which data will be exchanged
879 * @cmd: command to be written before data is read back
880 * Context: can sleep
881 *
882 * This returns the (unsigned) sixteen bit number returned by the device in cpu
883 * endianness, or else a negative error code. Callable only from contexts that
884 * can sleep.
885 *
886 * This function is similar to spi_w8r16, with the exception that it will
887 * convert the read 16 bit data word from big-endian to native endianness.
888 *
889 */
890static inline ssize_t spi_w8r16be(struct spi_device *spi, u8 cmd)
891
892{
893 ssize_t status;
894 __be16 result;
895
896 status = spi_write_then_read(spi, &cmd, 1, &result, 2);
897 if (status < 0)
898 return status;
899
900 return be16_to_cpu(result);
901}
902
David Brownell8ae12a02006-01-08 13:34:19 -0800903/*---------------------------------------------------------------------------*/
904
905/*
906 * INTERFACE between board init code and SPI infrastructure.
907 *
908 * No SPI driver ever sees these SPI device table segments, but
909 * it's how the SPI core (or adapters that get hotplugged) grows
910 * the driver model tree.
911 *
912 * As a rule, SPI devices can't be probed. Instead, board init code
913 * provides a table listing the devices which are present, with enough
914 * information to bind and set up the device's driver. There's basic
915 * support for nonstatic configurations too; enough to handle adding
916 * parport adapters, or microcontrollers acting as USB-to-SPI bridges.
917 */
918
David Brownell26042882007-07-31 00:39:44 -0700919/**
920 * struct spi_board_info - board-specific template for a SPI device
921 * @modalias: Initializes spi_device.modalias; identifies the driver.
922 * @platform_data: Initializes spi_device.platform_data; the particular
923 * data stored there is driver-specific.
924 * @controller_data: Initializes spi_device.controller_data; some
925 * controllers need hints about hardware setup, e.g. for DMA.
926 * @irq: Initializes spi_device.irq; depends on how the board is wired.
927 * @max_speed_hz: Initializes spi_device.max_speed_hz; based on limits
928 * from the chip datasheet and board-specific signal quality issues.
929 * @bus_num: Identifies which spi_master parents the spi_device; unused
930 * by spi_new_device(), and otherwise depends on board wiring.
931 * @chip_select: Initializes spi_device.chip_select; depends on how
932 * the board is wired.
933 * @mode: Initializes spi_device.mode; based on the chip datasheet, board
934 * wiring (some devices support both 3WIRE and standard modes), and
935 * possibly presence of an inverter in the chipselect path.
936 *
937 * When adding new SPI devices to the device tree, these structures serve
938 * as a partial device template. They hold information which can't always
939 * be determined by drivers. Information that probe() can establish (such
940 * as the default transfer wordsize) is not included here.
941 *
942 * These structures are used in two places. Their primary role is to
943 * be stored in tables of board-specific device descriptors, which are
944 * declared early in board initialization and then used (much later) to
945 * populate a controller's device tree after the that controller's driver
946 * initializes. A secondary (and atypical) role is as a parameter to
947 * spi_new_device() call, which happens after those controller drivers
948 * are active in some dynamic board configuration models.
949 */
David Brownell8ae12a02006-01-08 13:34:19 -0800950struct spi_board_info {
951 /* the device name and module name are coupled, like platform_bus;
952 * "modalias" is normally the driver name.
953 *
954 * platform_data goes to spi_device.dev.platform_data,
David Brownellb8852442006-01-08 13:34:23 -0800955 * controller_data goes to spi_device.controller_data,
David Brownell8ae12a02006-01-08 13:34:19 -0800956 * irq is copied too
957 */
Anton Vorontsov75368bf2009-09-22 16:46:04 -0700958 char modalias[SPI_NAME_SIZE];
David Brownell8ae12a02006-01-08 13:34:19 -0800959 const void *platform_data;
David Brownellb8852442006-01-08 13:34:23 -0800960 void *controller_data;
David Brownell8ae12a02006-01-08 13:34:19 -0800961 int irq;
962
963 /* slower signaling on noisy or low voltage boards */
964 u32 max_speed_hz;
965
966
967 /* bus_num is board specific and matches the bus_num of some
968 * spi_master that will probably be registered later.
969 *
970 * chip_select reflects how this chip is wired to that master;
971 * it's less than num_chipselect.
972 */
973 u16 bus_num;
974 u16 chip_select;
975
David Brownell980a01c2006-06-28 07:47:15 -0700976 /* mode becomes spi_device.mode, and is essential for chips
977 * where the default of SPI_CS_HIGH = 0 is wrong.
978 */
wangyuhangf477b7f2013-08-11 18:15:17 +0800979 u16 mode;
David Brownell980a01c2006-06-28 07:47:15 -0700980
David Brownell8ae12a02006-01-08 13:34:19 -0800981 /* ... may need additional spi_device chip config data here.
982 * avoid stuff protocol drivers can set; but include stuff
983 * needed to behave without being bound to a driver:
David Brownell8ae12a02006-01-08 13:34:19 -0800984 * - quirks like clock rate mattering when not selected
985 */
986};
987
988#ifdef CONFIG_SPI
989extern int
990spi_register_board_info(struct spi_board_info const *info, unsigned n);
991#else
992/* board init code may ignore whether SPI is configured or not */
993static inline int
994spi_register_board_info(struct spi_board_info const *info, unsigned n)
995 { return 0; }
996#endif
997
998
999/* If you're hotplugging an adapter with devices (parport, usb, etc)
David Brownell0c868462006-01-08 13:34:25 -08001000 * use spi_new_device() to describe each device. You can also call
1001 * spi_unregister_device() to start making that device vanish, but
1002 * normally that would be handled by spi_unregister_master().
Grant Likelydc87c982008-05-15 16:50:22 -06001003 *
1004 * You can also use spi_alloc_device() and spi_add_device() to use a two
1005 * stage registration sequence for each spi_device. This gives the caller
1006 * some more control over the spi_device structure before it is registered,
1007 * but requires that caller to initialize fields that would otherwise
1008 * be defined using the board info.
David Brownell8ae12a02006-01-08 13:34:19 -08001009 */
1010extern struct spi_device *
Grant Likelydc87c982008-05-15 16:50:22 -06001011spi_alloc_device(struct spi_master *master);
1012
1013extern int
1014spi_add_device(struct spi_device *spi);
1015
1016extern struct spi_device *
David Brownell8ae12a02006-01-08 13:34:19 -08001017spi_new_device(struct spi_master *, struct spi_board_info *);
1018
1019static inline void
1020spi_unregister_device(struct spi_device *spi)
1021{
1022 if (spi)
1023 device_unregister(&spi->dev);
1024}
1025
Anton Vorontsov75368bf2009-09-22 16:46:04 -07001026extern const struct spi_device_id *
1027spi_get_device_id(const struct spi_device *sdev);
1028
David Brownell8ae12a02006-01-08 13:34:19 -08001029#endif /* __LINUX_SPI_H */