From: Linus Walleij linus.wall...@linaro.org
This rips the message queue in the PL022 driver out and pushes
it into (optional) common infrastructure. Drivers that want to
use the message pumping thread will need to define the new
per-messags transfer methods and leave the deprecated transfer()
method as NULL.
Most of the design is described in the documentation changes that
are included in this patch.
Since there is a queue that need to be stopped when the system
is suspending/resuming, two new calls are implemented for the
device drivers to call in their suspend()/resume() functions:
spi_master_suspend() and spi_master_resume().
ChangeLog v1-v2:
- Remove Kconfig entry and do not make the queue support optional
at all, instead be more agressive and have it as part of the
compulsory infrastructure.
- If the .transfer() method is implemented, delete print a small
deprecation notice and do not start the transfer pump.
- Fix a bitrotted comment.
ChangeLog v2-v3:
- Fix up a problematic sequence courtesy of Chris Blair.
- Stop rather than destroy the queue on suspend() courtesy of
Chris Blair.
Cc: Mark Brown broo...@opensource.wolfsonmicro.com
Signed-off-by: Chris Blair chris.bl...@stericsson.com
Signed-off-by: Linus Walleij linus.wall...@linaro.org
---
Documentation/spi/spi-summary | 58 ++--
drivers/spi/spi-pl022.c | 303 +++--
drivers/spi/spi.c | 339 -
include/linux/spi/spi.h | 51 ++
4 files changed, 487 insertions(+), 264 deletions(-)
diff --git a/Documentation/spi/spi-summary b/Documentation/spi/spi-summary
index 4884cb3..7312ec1 100644
--- a/Documentation/spi/spi-summary
+++ b/Documentation/spi/spi-summary
@@ -1,7 +1,7 @@
Overview of Linux kernel SPI support
-21-May-2007
+02-Feb-2012
What is SPI?
@@ -483,9 +483,9 @@ also initialize its own internal state. (See below about
bus numbering
and those methods.)
After you initialize the spi_master, then use spi_register_master() to
-publish it to the rest of the system. At that time, device nodes for
-the controller and any predeclared spi devices will be made available,
-and the driver model core will take care of binding them to drivers.
+publish it to the rest of the system. At that time, device nodes for the
+controller and any predeclared spi devices will be made available, and
+the driver model core will take care of binding them to drivers.
If you need to remove your SPI controller driver, spi_unregister_master()
will reverse the effect of spi_register_master().
@@ -521,21 +521,53 @@ SPI MASTER METHODS
** When you code setup(), ASSUME that the controller
** is actively processing transfers for another device.
-master-transfer(struct spi_device *spi, struct spi_message *message)
- This must not sleep. Its responsibility is arrange that the
- transfer happens and its complete() callback is issued. The two
- will normally happen later, after other transfers complete, and
- if the controller is idle it will need to be kickstarted.
-
master-cleanup(struct spi_device *spi)
Your controller driver may use spi_device.controller_state to hold
state it dynamically associates with that device. If you do that,
be sure to provide the cleanup() method to free that state.
+master-prepare_transfer_hardware(struct spi_master *master)
+ This will be called by the queue mechanism to signal to the driver
+ that a message is coming in soon, so the subsystem requests the
+ driver to prepare the transfer hardware by issuing this call.
+ This may sleep.
+
+master-unprepare_transfer_hardware(struct spi_master *master)
+ This will be called by the queue mechanism to signal to the driver
+ that there are no more messages pending in the queue and it may
+ relax the hardware (e.g. by power management calls). This may sleep.
+
+master-transfer_one_message(struct spi_master *master,
+struct spi_message *mesg)
+ The subsystem calls the driver to transfer a single message while
+ queuing transfers that arrive in the meantime. When the driver is
+ finished with this message, it must call
+ spi_finalize_current_message() so the subsystem can issue the next
+ transfer. This may sleep.
+
+DEPRECATED METHODS
+
+master-transfer(struct spi_device *spi, struct spi_message *message)
+ This must not sleep. Its responsibility is arrange that the
+ transfer happens and its complete() callback is issued. The two
+ will normally happen later, after other transfers complete, and
+ if the controller is idle it will need to be kickstarted. This
+ method is not used on queued controllers and must be NULL if
+ transfer_one_message() and
