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-rw-r--r--drivers/spi/spi.c92
-rw-r--r--include/linux/spi/spi.h21
-rw-r--r--include/trace/events/spi.h42
3 files changed, 153 insertions, 2 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 8a30c6b..85c18d8 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -526,6 +526,95 @@ int spi_register_board_info(struct spi_board_info const *info, unsigned n)
/*-------------------------------------------------------------------------*/
+static void spi_set_cs(struct spi_device *spi, bool enable)
+{
+ if (spi->mode & SPI_CS_HIGH)
+ enable = !enable;
+
+ if (spi->cs_gpio >= 0)
+ gpio_set_value(spi->cs_gpio, !enable);
+ else if (spi->master->set_cs)
+ spi->master->set_cs(spi, !enable);
+}
+
+/*
+ * spi_transfer_one_message - Default implementation of transfer_one_message()
+ *
+ * This is a standard implementation of transfer_one_message() for
+ * drivers which impelment a transfer_one() operation. It provides
+ * standard handling of delays and chip select management.
+ */
+static int spi_transfer_one_message(struct spi_master *master,
+ struct spi_message *msg)
+{
+ struct spi_transfer *xfer;
+ bool cur_cs = true;
+ bool keep_cs = false;
+ int ret = 0;
+
+ spi_set_cs(msg->spi, true);
+
+ list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+ trace_spi_transfer_start(msg, xfer);
+
+ INIT_COMPLETION(master->xfer_completion);
+
+ ret = master->transfer_one(master, msg->spi, xfer);
+ if (ret < 0) {
+ dev_err(&msg->spi->dev,
+ "SPI transfer failed: %d\n", ret);
+ goto out;
+ }
+
+ if (ret > 0)
+ wait_for_completion(&master->xfer_completion);
+
+ trace_spi_transfer_stop(msg, xfer);
+
+ if (msg->status != -EINPROGRESS)
+ goto out;
+
+ if (xfer->delay_usecs)
+ udelay(xfer->delay_usecs);
+
+ if (xfer->cs_change) {
+ if (list_is_last(&xfer->transfer_list,
+ &msg->transfers)) {
+ keep_cs = true;
+ } else {
+ cur_cs = !cur_cs;
+ spi_set_cs(msg->spi, cur_cs);
+ }
+ }
+
+ msg->actual_length += xfer->len;
+ }
+
+out:
+ if (ret != 0 || !keep_cs)
+ spi_set_cs(msg->spi, false);
+
+ if (msg->status == -EINPROGRESS)
+ msg->status = ret;
+
+ spi_finalize_current_message(master);
+
+ return ret;
+}
+
+/**
+ * spi_finalize_current_transfer - report completion of a transfer
+ *
+ * Called by SPI drivers using the core transfer_one_message()
+ * implementation to notify it that the current interrupt driven
+ * transfer has finised and the next one may be scheduled.
+ */
+void spi_finalize_current_transfer(struct spi_master *master)
+{
+ complete(&master->xfer_completion);
+}
+EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
+
/**
* spi_pump_messages - kthread work function which processes spi message queue
* @work: pointer to kthread work struct contained in the master struct
@@ -836,6 +925,8 @@ static int spi_master_initialize_queue(struct spi_master *master)
master->queued = true;
master->transfer = spi_queued_transfer;
+ if (!master->transfer_one_message)
+ master->transfer_one_message = spi_transfer_one_message;
/* Initialize and start queue */
ret = spi_init_queue(master);
@@ -1242,6 +1333,7 @@ int spi_register_master(struct spi_master *master)
spin_lock_init(&master->bus_lock_spinlock);
mutex_init(&master->bus_lock_mutex);
master->bus_lock_flag = 0;
+ init_completion(&master->xfer_completion);
/* register the device, then userspace will see it.
* registration fails if the bus ID is in use.
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 000b50b..da371ab 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -23,6 +23,7 @@
#include <linux/mod_devicetable.h>
#include <linux/slab.h>
#include <linux/kthread.h>
+#include <linux/completion.h>
/*
* INTERFACES between SPI master-side drivers and SPI infrastructure.
@@ -150,8 +151,7 @@ static inline void *spi_get_drvdata(struct spi_device *spi)
}
struct spi_message;
-
-
+struct spi_transfer;
/**
* struct spi_driver - Host side "protocol" driver
@@ -259,6 +259,7 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv)
* @cur_msg: the currently in-flight message
* @cur_msg_prepared: spi_prepare_message was called for the currently
* in-flight message
+ * @xfer_completion: used by core tranfer_one_message()
* @busy: message pump is busy
* @running: message pump is running
* @rt: whether this queue is set to run as a realtime task
@@ -276,9 +277,15 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv)
* @unprepare_transfer_hardware: there are currently no more messages on the
* queue so the subsystem notifies the driver that it may relax the
* hardware by issuing this call
+ * @set_cs: assert or deassert chip select, true to assert. May be called
+ * from interrupt context.
* @prepare_message: set up the controller to transfer a single message,
* for example doing DMA mapping. Called from threaded
* context.
+ * @transfer_one: transfer a single spi_transfer. When the
+ * driver is finished with this transfer it must call
+ * spi_finalize_current_transfer() so the subsystem can issue
+ * the next transfer
* @unprepare_message: undo any work done by prepare_message().
* @cs_gpios: Array of GPIOs to use as chip select lines; one per CS
* number. Any individual value may be -ENOENT for CS lines that
@@ -395,6 +402,7 @@ struct spi_master {
bool rt;
bool auto_runtime_pm;
bool cur_msg_prepared;
+ struct completion xfer_completion;
int (*prepare_transfer_hardware)(struct spi_master *master);
int (*transfer_one_message)(struct spi_master *master,
@@ -405,6 +413,14 @@ struct spi_master {
int (*unprepare_message)(struct spi_master *master,
struct spi_message *message);
+ /*
+ * These hooks are for drivers that use a generic implementation
+ * of transfer_one_message() provied by the core.
+ */
+ void (*set_cs)(struct spi_device *spi, bool enable);
+ int (*transfer_one)(struct spi_master *master, struct spi_device *spi,
+ struct spi_transfer *transfer);
+
/* gpio chip select */
int *cs_gpios;
};
@@ -439,6 +455,7 @@ extern int spi_master_resume(struct spi_master *master);
/* Calls the driver make to interact with the message queue */
extern struct spi_message *spi_get_next_queued_message(struct spi_master *master);
extern void spi_finalize_current_message(struct spi_master *master);
+extern void spi_finalize_current_transfer(struct spi_master *master);
/* the spi driver core manages memory for the spi_master classdev */
extern struct spi_master *
diff --git a/include/trace/events/spi.h b/include/trace/events/spi.h
index 5e77e21..7e02c98 100644
--- a/include/trace/events/spi.h
+++ b/include/trace/events/spi.h
@@ -108,6 +108,48 @@ TRACE_EVENT(spi_message_done,
(unsigned)__entry->actual, (unsigned)__entry->frame)
);
+DECLARE_EVENT_CLASS(spi_transfer,
+
+ TP_PROTO(struct spi_message *msg, struct spi_transfer *xfer),
+
+ TP_ARGS(msg, xfer),
+
+ TP_STRUCT__entry(
+ __field( int, bus_num )
+ __field( int, chip_select )
+ __field( struct spi_transfer *, xfer )
+ __field( int, len )
+ ),
+
+ TP_fast_assign(
+ __entry->bus_num = msg->spi->master->bus_num;
+ __entry->chip_select = msg->spi->chip_select;
+ __entry->xfer = xfer;
+ __entry->len = xfer->len;
+ ),
+
+ TP_printk("spi%d.%d %p len=%d", (int)__entry->bus_num,
+ (int)__entry->chip_select,
+ (struct spi_message *)__entry->xfer,
+ (int)__entry->len)
+);
+
+DEFINE_EVENT(spi_transfer, spi_transfer_start,
+
+ TP_PROTO(struct spi_message *msg, struct spi_transfer *xfer),
+
+ TP_ARGS(msg, xfer)
+
+);
+
+DEFINE_EVENT(spi_transfer, spi_transfer_stop,
+
+ TP_PROTO(struct spi_message *msg, struct spi_transfer *xfer),
+
+ TP_ARGS(msg, xfer)
+
+);
+
#endif /* _TRACE_POWER_H */
/* This part must be outside protection */
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