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-rw-r--r--include/linux/spi/spi.h235
1 files changed, 138 insertions, 97 deletions
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index c459809efee4..4789f91dae94 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -31,9 +31,11 @@ struct spi_transfer;
struct spi_controller_mem_ops;
struct spi_controller_mem_caps;
struct spi_message;
+struct spi_offload;
+struct spi_offload_config;
/*
- * INTERFACES between SPI master-side drivers and SPI slave protocol handlers,
+ * INTERFACES between SPI controller-side drivers and SPI target protocol handlers,
* and SPI infrastructure.
*/
extern const struct bus_type spi_bus_type;
@@ -128,19 +130,12 @@ extern void spi_transfer_cs_change_delay_exec(struct spi_message *msg,
struct spi_transfer *xfer);
/**
- * struct spi_device - Controller side proxy for an SPI slave device
+ * struct spi_device - Controller side proxy for an SPI target device
* @dev: Driver model representation of the device.
* @controller: SPI controller used with the device.
* @max_speed_hz: Maximum clock rate to be used with this chip
* (on this board); may be changed by the device's driver.
* The spi_transfer.speed_hz can override this for each transfer.
- * @chip_select: Array of physical chipselect, spi->chipselect[i] gives
- * the corresponding physical CS for logical CS i.
- * @mode: The spi mode defines how data is clocked out and in.
- * This may be changed by the device's driver.
- * The "active low" default for chipselect mode can be overridden
- * (by specifying SPI_CS_HIGH) as can the "MSB first" default for
- * each word in a transfer (by specifying SPI_LSB_FIRST).
* @bits_per_word: Data transfers involve one or more words; word sizes
* like eight or 12 bits are common. In-memory wordsizes are
* powers of two bytes (e.g. 20 bit samples use 32 bits).
@@ -148,6 +143,11 @@ extern void spi_transfer_cs_change_delay_exec(struct spi_message *msg,
* default (0) indicating protocol words are eight bit bytes.
* The spi_transfer.bits_per_word can override this for each transfer.
* @rt: Make the pump thread real time priority.
+ * @mode: The spi mode defines how data is clocked out and in.
+ * This may be changed by the device's driver.
+ * The "active low" default for chipselect mode can be overridden
+ * (by specifying SPI_CS_HIGH) as can the "MSB first" default for
+ * each word in a transfer (by specifying SPI_LSB_FIRST).
* @irq: Negative, or the number passed to request_irq() to receive
* interrupts from this device.
* @controller_state: Controller's runtime state
@@ -160,8 +160,7 @@ extern void spi_transfer_cs_change_delay_exec(struct spi_message *msg,
* the device will bind to the named driver and only the named driver.
* Do not set directly, because core frees it; use driver_set_override() to
* set or clear it.
- * @cs_gpiod: Array of GPIO descriptors of the corresponding chipselect lines
- * (optional, NULL when not using a GPIO line)
+ * @pcpu_statistics: statistics for the spi_device
* @word_delay: delay to be inserted between consecutive
* words of a transfer
* @cs_setup: delay to be introduced by the controller after CS is asserted
@@ -169,10 +168,13 @@ extern void spi_transfer_cs_change_delay_exec(struct spi_message *msg,
* @cs_inactive: delay to be introduced by the controller after CS is
* deasserted. If @cs_change_delay is used from @spi_transfer, then the
* two delays will be added up.
- * @pcpu_statistics: statistics for the spi_device
+ * @chip_select: Array of physical chipselect, spi->chipselect[i] gives
+ * the corresponding physical CS for logical CS i.
* @cs_index_mask: Bit mask of the active chipselect(s) in the chipselect array
+ * @cs_gpiod: Array of GPIO descriptors of the corresponding chipselect lines
+ * (optional, NULL when not using a GPIO line)
*
- * A @spi_device is used to interchange data between an SPI slave
+ * A @spi_device is used to interchange data between an SPI target device
* (usually a discrete chip) and CPU memory.
*
* In @dev, the platform_data is used to hold information about this
@@ -185,7 +187,6 @@ struct spi_device {
struct device dev;
struct spi_controller *controller;
u32 max_speed_hz;
- u8 chip_select[SPI_CS_CNT_MAX];
u8 bits_per_word;
bool rt;
#define SPI_NO_TX BIT(31) /* No transmit wire */
@@ -216,23 +217,29 @@ struct spi_device {
void *controller_data;
char modalias[SPI_NAME_SIZE];
const char *driver_override;
- struct gpio_desc *cs_gpiod[SPI_CS_CNT_MAX]; /* Chip select gpio desc */
+
+ /* The statistics */
+ struct spi_statistics __percpu *pcpu_statistics;
+
struct spi_delay word_delay; /* Inter-word delay */
+
/* CS delays */
struct spi_delay cs_setup;
struct spi_delay cs_hold;
struct spi_delay cs_inactive;
- /* The statistics */
- struct spi_statistics __percpu *pcpu_statistics;
+ u8 chip_select[SPI_CS_CNT_MAX];
- /* Bit mask of the chipselect(s) that the driver need to use from
- * the chipselect array.When the controller is capable to handle
+ /*
+ * Bit mask of the chipselect(s) that the driver need to use from
+ * the chipselect array. When the controller is capable to handle
* multiple chip selects & memories are connected in parallel
* then more than one bit need to be set in cs_index_mask.
*/
u32 cs_index_mask : SPI_CS_CNT_MAX;
+ struct gpio_desc *cs_gpiod[SPI_CS_CNT_MAX]; /* Chip select gpio desc */
+
/*
* Likely need more hooks for more protocol options affecting how
* the controller talks to each chip, like:
@@ -247,10 +254,7 @@ struct spi_device {
static_assert((SPI_MODE_KERNEL_MASK & SPI_MODE_USER_MASK) == 0,
"SPI_MODE_USER_MASK & SPI_MODE_KERNEL_MASK must not overlap");
-static inline struct spi_device *to_spi_device(const struct device *dev)
-{
- return dev ? container_of(dev, struct spi_device, dev) : NULL;
-}
+#define to_spi_device(__dev) container_of_const(__dev, struct spi_device, dev)
/* Most drivers won't need to care about device refcounting */
static inline struct spi_device *spi_dev_get(struct spi_device *spi)
@@ -351,10 +355,8 @@ struct spi_driver {
struct device_driver driver;
};
-static inline struct spi_driver *to_spi_driver(struct device_driver *drv)
-{
- return drv ? container_of(drv, struct spi_driver, driver) : NULL;
-}
+#define to_spi_driver(__drv) \
+ ( __drv ? container_of_const(__drv, struct spi_driver, driver) : NULL )
extern int __spi_register_driver(struct module *owner, struct spi_driver *sdrv);
@@ -388,15 +390,15 @@ extern struct spi_device *spi_new_ancillary_device(struct spi_device *spi, u8 ch
spi_unregister_driver)
/**
- * struct spi_controller - interface to SPI master or slave controller
+ * struct spi_controller - interface to SPI host or target controller
* @dev: device interface to this driver
* @list: link with the global spi_controller list
* @bus_num: board-specific (and often SOC-specific) identifier for a
* given SPI controller.
* @num_chipselect: chipselects are used to distinguish individual
- * SPI slaves, and are numbered from zero to num_chipselects.
- * each slave has a chipselect signal, but it's common that not
- * every chipselect is connected to a slave.
+ * SPI targets, and are numbered from zero to num_chipselects.
+ * each target has a chipselect signal, but it's common that not
+ * every chipselect is connected to a target.
* @dma_alignment: SPI controller constraint on DMA buffers alignment.
* @mode_bits: flags understood by this controller driver
* @buswidth_override_bits: flags to override for this controller driver
@@ -425,9 +427,9 @@ extern struct spi_device *spi_new_ancillary_device(struct spi_device *spi, u8 ch
* must fail if an unrecognized or unsupported mode is requested.
* It's always safe to call this unless transfers are pending on
* the device whose settings are being modified.
- * @set_cs_timing: optional hook for SPI devices to request SPI master
+ * @set_cs_timing: optional hook for SPI devices to request SPI
* controller for configuring specific CS setup time, hold time and inactive
- * delay interms of clock counts
+ * delay in terms of clock counts
* @transfer: adds a message to the controller's transfer queue.
* @cleanup: frees controller-specific state
* @can_dma: determine whether this controller supports DMA
@@ -447,12 +449,12 @@ extern struct spi_device *spi_new_ancillary_device(struct spi_device *spi, u8 ch
* @cur_msg_need_completion: Flag used internally to opportunistically skip
* the @cur_msg_completion. This flag is used to signal the context that
* is running spi_finalize_current_message() that it needs to complete()
- * @cur_msg_mapped: message has been mapped for DMA
* @fallback: fallback to PIO if DMA transfer return failure with
* SPI_TRANS_FAIL_NO_START.
* @last_cs_mode_high: was (mode & SPI_CS_HIGH) true on the last call to set_cs.
* @last_cs: the last chip_select that is recorded by set_cs, -1 on non chip
* selected
+ * @last_cs_index_mask: bit mask the last chip selects that were used
* @xfer_completion: used by core transfer_one_message()
* @busy: message pump is busy
* @running: message pump is running
@@ -498,9 +500,14 @@ extern struct spi_device *spi_new_ancillary_device(struct spi_device *spi, u8 ch
* @mem_ops: optimized/dedicated operations for interactions with SPI memory.
* This field is optional and should only be implemented if the
* controller has native support for memory like operations.
+ * @get_offload: callback for controllers with offload support to get matching
+ * offload instance. Implementations should return -ENODEV if no match is
+ * found.
+ * @put_offload: release the offload instance acquired by @get_offload.
* @mem_caps: controller capabilities for the handling of memory operations.
+ * @dtr_caps: true if controller has dtr(single/dual transfer rate) capability.
+ * QSPI based controller should fill this based on controller's capability.
* @unprepare_message: undo any work done by prepare_message().
- * @slave_abort: abort the ongoing transfer request on an SPI slave controller
* @target_abort: abort the ongoing transfer request on an SPI target controller
* @cs_gpiods: Array of GPIO descriptors to use as chip select lines; one per CS
* number. Any individual value may be NULL for CS lines that
@@ -532,6 +539,9 @@ extern struct spi_device *spi_new_ancillary_device(struct spi_device *spi, u8 ch
* @queue_empty: signal green light for opportunistically skipping the queue
* for spi_sync transfers.
* @must_async: disable all fast paths in the core
+ * @defer_optimize_message: set to true if controller cannot pre-optimize messages
+ * and needs to defer the optimization step until the message is actually
+ * being transferred
*
* Each SPI controller can communicate with one or more @spi_device
* children. These make a small bus, sharing MOSI, MISO and SCK signals
@@ -541,7 +551,7 @@ extern struct spi_device *spi_new_ancillary_device(struct spi_device *spi, u8 ch
*
* The driver for an SPI controller manages access to those devices through
* a queue of spi_message transactions, copying data between CPU memory and
- * an SPI slave device. For each such message it queues, it calls the
+ * an SPI target device. For each such message it queues, it calls the
* message's completion function when the transaction completes.
*/
struct spi_controller {
@@ -591,7 +601,7 @@ struct spi_controller {
#define SPI_CONTROLLER_NO_TX BIT(2) /* Can't do buffer write */
#define SPI_CONTROLLER_MUST_RX BIT(3) /* Requires rx */
#define SPI_CONTROLLER_MUST_TX BIT(4) /* Requires tx */
-#define SPI_CONTROLLER_GPIO_SS BIT(5) /* GPIO CS must select slave */
+#define SPI_CONTROLLER_GPIO_SS BIT(5) /* GPIO CS must select target device */
#define SPI_CONTROLLER_SUSPENDED BIT(6) /* Currently suspended */
/*
* The spi-controller has multi chip select capability and can
@@ -658,7 +668,7 @@ struct spi_controller {
* + To a given spi_device, message queueing is pure FIFO
*
* + The controller's main job is to process its message queue,
- * selecting a chip (for masters), then transferring data
+ * selecting a chip (for controllers), then transferring data
* + If there are multiple spi_device children, the i/o queue
* arbitration algorithm is unspecified (round robin, FIFO,
* priority, reservations, preemption, etc)
@@ -707,7 +717,6 @@ struct spi_controller {
bool running;
bool rt;
bool auto_runtime_pm;
- bool cur_msg_mapped;
bool fallback;
bool last_cs_mode_high;
s8 last_cs[SPI_CS_CNT_MAX];
@@ -725,10 +734,7 @@ struct spi_controller {
struct spi_message *message);
int (*unprepare_message)(struct spi_controller *ctlr,
struct spi_message *message);
- union {
- int (*slave_abort)(struct spi_controller *ctlr);
- int (*target_abort)(struct spi_controller *ctlr);
- };
+ int (*target_abort)(struct spi_controller *ctlr);
/*
* These hooks are for drivers that use a generic implementation
@@ -744,6 +750,13 @@ struct spi_controller {
const struct spi_controller_mem_ops *mem_ops;
const struct spi_controller_mem_caps *mem_caps;
+ /* SPI or QSPI controller can set to true if supports SDR/DDR transfer rate */
+ bool dtr_caps;
+
+ struct spi_offload *(*get_offload)(struct spi_device *spi,
+ const struct spi_offload_config *config);
+ void (*put_offload)(struct spi_offload *offload);
+
/* GPIO chip select */
struct gpio_desc **cs_gpiods;
bool use_gpio_descriptors;
@@ -775,6 +788,7 @@ struct spi_controller {
/* Flag for enabling opportunistic skipping of the queue in spi_sync */
bool queue_empty;
bool must_async;
+ bool defer_optimize_message;
};
static inline void *spi_controller_get_devdata(struct spi_controller *ctlr)
@@ -801,11 +815,6 @@ static inline void spi_controller_put(struct spi_controller *ctlr)
put_device(&ctlr->dev);
}
-static inline bool spi_controller_is_slave(struct spi_controller *ctlr)
-{
- return IS_ENABLED(CONFIG_SPI_SLAVE) && ctlr->slave;
-}
-
static inline bool spi_controller_is_target(struct spi_controller *ctlr)
{
return IS_ENABLED(CONFIG_SPI_SLAVE) && ctlr->target;
@@ -830,22 +839,7 @@ void spi_take_timestamp_post(struct spi_controller *ctlr,
/* The SPI driver core manages memory for the spi_controller classdev */
extern struct spi_controller *__spi_alloc_controller(struct device *host,
- unsigned int size, bool slave);
-
-static inline struct spi_controller *spi_alloc_master(struct device *host,
- unsigned int size)
-{
- return __spi_alloc_controller(host, size, false);
-}
-
-static inline struct spi_controller *spi_alloc_slave(struct device *host,
- unsigned int size)
-{
- if (!IS_ENABLED(CONFIG_SPI_SLAVE))
- return NULL;
-
- return __spi_alloc_controller(host, size, true);
-}
+ unsigned int size, bool target);
static inline struct spi_controller *spi_alloc_host(struct device *dev,
unsigned int size)
@@ -864,22 +858,7 @@ static inline struct spi_controller *spi_alloc_target(struct device *dev,
struct spi_controller *__devm_spi_alloc_controller(struct device *dev,
unsigned int size,
- bool slave);
-
-static inline struct spi_controller *devm_spi_alloc_master(struct device *dev,
- unsigned int size)
-{
- return __devm_spi_alloc_controller(dev, size, false);
-}
-
-static inline struct spi_controller *devm_spi_alloc_slave(struct device *dev,
- unsigned int size)
-{
- if (!IS_ENABLED(CONFIG_SPI_SLAVE))
- return NULL;
-
- return __devm_spi_alloc_controller(dev, size, true);
-}
+ bool target);
static inline struct spi_controller *devm_spi_alloc_host(struct device *dev,
unsigned int size)
@@ -901,12 +880,29 @@ extern int devm_spi_register_controller(struct device *dev,
struct spi_controller *ctlr);
extern void spi_unregister_controller(struct spi_controller *ctlr);
-#if IS_ENABLED(CONFIG_ACPI)
+#if IS_ENABLED(CONFIG_ACPI) && IS_ENABLED(CONFIG_SPI_MASTER)
extern struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev);
extern struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
struct acpi_device *adev,
int index);
int acpi_spi_count_resources(struct acpi_device *adev);
+#else
+static inline struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
+{
+ return NULL;
+}
+
+static inline struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
+ struct acpi_device *adev,
+ int index)
+{
+ return ERR_PTR(-ENODEV);
+}
+
+static inline int acpi_spi_count_resources(struct acpi_device *adev)
+{
+ return 0;
+}
#endif
/*
@@ -955,8 +951,8 @@ struct spi_res {
* struct spi_transfer - a read/write buffer pair
* @tx_buf: data to be written (DMA-safe memory), or NULL
* @rx_buf: data to be read (DMA-safe memory), or NULL
- * @tx_dma: DMA address of tx_buf, if @spi_message.is_dma_mapped
- * @rx_dma: DMA address of rx_buf, if @spi_message.is_dma_mapped
+ * @tx_dma: DMA address of tx_buf, currently not for client use
+ * @rx_dma: DMA address of rx_buf, currently not for client use
* @tx_nbits: number of bits used for writing. If 0 the default
* (SPI_NBITS_SINGLE) is used.
* @rx_nbits: number of bits used for reading. If 0 the default
@@ -980,8 +976,12 @@ struct spi_res {
* transfer this transfer. Set to 0 if the SPI bus driver does
* not support it.
* @transfer_list: transfers are sequenced through @spi_message.transfers
+ * @tx_sg_mapped: If true, the @tx_sg is mapped for DMA
+ * @rx_sg_mapped: If true, the @rx_sg is mapped for DMA
* @tx_sg: Scatterlist for transmit, currently not for client use
* @rx_sg: Scatterlist for receive, currently not for client use
+ * @offload_flags: Flags that are only applicable to specialized SPI offload
+ * transfers. See %SPI_OFFLOAD_XFER_* in spi-offload.h.
* @ptp_sts_word_pre: The word (subject to bits_per_word semantics) offset
* within @tx_buf for which the SPI device is requesting that the time
* snapshot for this transfer begins. Upon completing the SPI transfer,
@@ -996,15 +996,16 @@ struct spi_res {
* purposefully (instead of setting to spi_transfer->len - 1) to denote
* that a transfer-level snapshot taken from within the driver may still
* be of higher quality.
- * @ptp_sts: Pointer to a memory location held by the SPI slave device where a
+ * @ptp_sts: Pointer to a memory location held by the SPI target device where a
* PTP system timestamp structure may lie. If drivers use PIO or their
* hardware has some sort of assist for retrieving exact transfer timing,
* they can (and should) assert @ptp_sts_supported and populate this
* structure using the ptp_read_system_*ts helper functions.
- * The timestamp must represent the time at which the SPI slave device has
+ * The timestamp must represent the time at which the SPI target device has
* processed the word, i.e. the "pre" timestamp should be taken before
* transmitting the "pre" word, and the "post" timestamp after receiving
* transmit confirmation from the controller for the "post" word.
+ * @dtr_mode: true if supports double transfer rate.
* @timestamped: true if the transfer has been timestamped
* @error: Error status logged by SPI controller driver.
*
@@ -1056,6 +1057,9 @@ struct spi_res {
* two should both be set. User can set transfer mode with SPI_NBITS_SINGLE(1x)
* SPI_NBITS_DUAL(2x) and SPI_NBITS_QUAD(4x) to support these three transfer.
*
+ * User may also set dtr_mode to true to use dual transfer mode if desired. if
+ * not, default considered as single transfer mode.
+ *
* The code that submits an spi_message (and its spi_transfers)
* to the lower layers is responsible for managing its memory.
* Zero-initialize every field you don't set up explicitly, to
@@ -1066,8 +1070,7 @@ struct spi_transfer {
/*
* It's okay if tx_buf == rx_buf (right?).
* For MicroWire, one buffer must be NULL.
- * Buffers must work with dma_*map_single() calls, unless
- * spi_message.is_dma_mapped reports a pre-existing mapping.
+ * Buffers must work with dma_*map_single() calls.
*/
const void *tx_buf;
void *rx_buf;
@@ -1077,20 +1080,25 @@ struct spi_transfer {
#define SPI_TRANS_FAIL_IO BIT(1)
u16 error;
- dma_addr_t tx_dma;
- dma_addr_t rx_dma;
+ bool tx_sg_mapped;
+ bool rx_sg_mapped;
+
struct sg_table tx_sg;
struct sg_table rx_sg;
+ dma_addr_t tx_dma;
+ dma_addr_t rx_dma;
unsigned dummy_data:1;
unsigned cs_off:1;
unsigned cs_change:1;
- unsigned tx_nbits:3;
- unsigned rx_nbits:3;
+ unsigned tx_nbits:4;
+ unsigned rx_nbits:4;
unsigned timestamped:1;
+ bool dtr_mode;
#define SPI_NBITS_SINGLE 0x01 /* 1-bit transfer */
#define SPI_NBITS_DUAL 0x02 /* 2-bit transfer */
#define SPI_NBITS_QUAD 0x04 /* 4-bit transfer */
+#define SPI_NBITS_OCTAL 0x08 /* 8-bit transfer */
u8 bits_per_word;
struct spi_delay delay;
struct spi_delay cs_change_delay;
@@ -1099,6 +1107,9 @@ struct spi_transfer {
u32 effective_speed_hz;
+ /* Use %SPI_OFFLOAD_XFER_* from spi-offload.h */
+ unsigned int offload_flags;
+
unsigned int ptp_sts_word_pre;
unsigned int ptp_sts_word_post;
@@ -1111,8 +1122,6 @@ struct spi_transfer {
* struct spi_message - one multi-segment SPI transaction
* @transfers: list of transfer segments in this transaction
* @spi: SPI device to which the transaction is queued
- * @is_dma_mapped: if true, the caller provided both DMA and CPU virtual
- * addresses for each transfer buffer
* @pre_optimized: peripheral driver pre-optimized the message
* @optimized: the message is in the optimized state
* @prepared: spi_prepare_message was called for the this message
@@ -1126,6 +1135,7 @@ struct spi_transfer {
* @state: for use by whichever driver currently owns the message
* @opt_state: for use by whichever driver currently owns the message
* @resources: for resource management when the SPI message is processed
+ * @offload: (optional) offload instance used by this message
*
* A @spi_message is used to execute an atomic sequence of data transfers,
* each represented by a struct spi_transfer. The sequence is "atomic"
@@ -1146,8 +1156,6 @@ struct spi_message {
struct spi_device *spi;
- unsigned is_dma_mapped:1;
-
/* spi_optimize_message() was called for this message */
bool pre_optimized;
/* __spi_optimize_message() was called for this message */
@@ -1188,6 +1196,12 @@ struct spi_message {
*/
void *opt_state;
+ /*
+ * Optional offload instance used by this message. This must be set
+ * by the peripheral driver before calling spi_optimize_message().
+ */
+ struct spi_offload *offload;
+
/* List of spi_res resources when the SPI message is processed */
struct list_head resources;
};
@@ -1272,10 +1286,11 @@ static inline void spi_message_free(struct spi_message *m)
extern int spi_optimize_message(struct spi_device *spi, struct spi_message *msg);
extern void spi_unoptimize_message(struct spi_message *msg);
+extern int devm_spi_optimize_message(struct device *dev, struct spi_device *spi,
+ struct spi_message *msg);
extern int spi_setup(struct spi_device *spi);
extern int spi_async(struct spi_device *spi, struct spi_message *message);
-extern int spi_slave_abort(struct spi_device *spi);
extern int spi_target_abort(struct spi_device *spi);
static inline size_t
@@ -1323,6 +1338,32 @@ static inline bool spi_is_bpw_supported(struct spi_device *spi, u32 bpw)
}
/**
+ * spi_bpw_to_bytes - Covert bits per word to bytes
+ * @bpw: Bits per word
+ *
+ * This function converts the given @bpw to bytes. The result is always
+ * power-of-two, e.g.,
+ *
+ * =============== =================
+ * Input (in bits) Output (in bytes)
+ * =============== =================
+ * 5 1
+ * 9 2
+ * 21 4
+ * 37 8
+ * =============== =================
+ *
+ * It will return 0 for the 0 input.
+ *
+ * Returns:
+ * Bytes for the given @bpw.
+ */
+static inline u32 spi_bpw_to_bytes(u32 bpw)
+{
+ return roundup_pow_of_two(BITS_TO_BYTES(bpw));
+}
+
+/**
* spi_controller_xfer_timeout - Compute a suitable timeout value
* @ctlr: SPI device
* @xfer: Transfer descriptor
@@ -1619,7 +1660,7 @@ struct spi_board_info {
* bus_num is board specific and matches the bus_num of some
* spi_controller that will probably be registered later.
*
- * chip_select reflects how this chip is wired to that master;
+ * chip_select reflects how this chip is wired to that controller;
* it's less than num_chipselect.
*/
u16 bus_num;