[PATCH] spi: add spi_driver to SPI framework
This is a refresh of the "Simple SPI Framework" found in 2.6.15-rc3-mm1
which makes the following changes:
* There's now a "struct spi_driver". This increase the footprint
of the core a bit, since it now includes code to do what the driver
core was previously handling directly. Documentation and comments
were updated to match.
* spi_alloc_master() now does class_device_initialize(), so it can
at least be refcounted before spi_register_master(). To match,
spi_register_master() switched over to class_device_add().
* States explicitly that after transfer errors, spi_devices will be
deselected. We want fault recovery procedures to work the same
for all controller drivers.
* Minor tweaks: controller_data no longer points to readonly data;
prevent some potential cast-from-null bugs with container_of calls;
clarifies some existing kerneldoc,
And a few small cleanups.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 51a6769..c851b3d 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -20,13 +20,8 @@
#define __LINUX_SPI_H
/*
- * INTERFACES between SPI master drivers and infrastructure
+ * INTERFACES between SPI master-side drivers and SPI infrastructure.
* (There's no SPI slave support for Linux yet...)
- *
- * A "struct device_driver" for an spi_device uses "spi_bus_type" and
- * needs no special API wrappers (much like platform_bus). These drivers
- * are bound to devices based on their names (much like platform_bus),
- * and are available in dev->driver.
*/
extern struct bus_type spi_bus_type;
@@ -46,8 +41,8 @@
* @irq: Negative, or the number passed to request_irq() to receive
* interrupts from this device.
* @controller_state: Controller's runtime state
- * @controller_data: Static board-specific definitions for controller, such
- * as FIFO initialization parameters; from board_info.controller_data
+ * @controller_data: Board-specific definitions for controller, such as
+ * FIFO initialization parameters; from board_info.controller_data
*
* An spi_device is used to interchange data between an SPI slave
* (usually a discrete chip) and CPU memory.
@@ -63,31 +58,32 @@
u32 max_speed_hz;
u8 chip_select;
u8 mode;
-#define SPI_CPHA 0x01 /* clock phase */
-#define SPI_CPOL 0x02 /* clock polarity */
+#define SPI_CPHA 0x01 /* clock phase */
+#define SPI_CPOL 0x02 /* clock polarity */
#define SPI_MODE_0 (0|0)
-#define SPI_MODE_1 (0|SPI_CPHA)
+#define SPI_MODE_1 (0|SPI_CPHA) /* (original MicroWire) */
#define SPI_MODE_2 (SPI_CPOL|0)
#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
-#define SPI_CS_HIGH 0x04 /* chipselect active high? */
+#define SPI_CS_HIGH 0x04 /* chipselect active high? */
u8 bits_per_word;
int irq;
void *controller_state;
- const void *controller_data;
+ void *controller_data;
const char *modalias;
// likely need more hooks for more protocol options affecting how
- // the controller talks to its chips, like:
+ // the controller talks to each chip, like:
// - bit order (default is wordwise msb-first)
// - memory packing (12 bit samples into low bits, others zeroed)
// - priority
+ // - drop chipselect after each word
// - chipselect delays
// - ...
};
static inline struct spi_device *to_spi_device(struct device *dev)
{
- return container_of(dev, struct spi_device, dev);
+ return dev ? container_of(dev, struct spi_device, dev) : NULL;
}
/* most drivers won't need to care about device refcounting */
@@ -117,12 +113,38 @@
struct spi_message;
+
+struct spi_driver {
+ int (*probe)(struct spi_device *spi);
+ int (*remove)(struct spi_device *spi);
+ void (*shutdown)(struct spi_device *spi);
+ int (*suspend)(struct spi_device *spi, pm_message_t mesg);
+ int (*resume)(struct spi_device *spi);
+ 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;
+}
+
+extern int spi_register_driver(struct spi_driver *sdrv);
+
+static inline void spi_unregister_driver(struct spi_driver *sdrv)
+{
+ if (!sdrv)
+ return;
+ driver_unregister(&sdrv->driver);
+}
+
+
+
/**
* struct spi_master - interface to SPI master controller
* @cdev: class interface to this driver
* @bus_num: board-specific (and often SOC-specific) identifier for a
* given SPI controller.
- * @num_chipselects: chipselects are used to distinguish individual
+ * @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.
@@ -275,7 +297,8 @@
* addresses for each transfer buffer
* @complete: called to report transaction completions
* @context: the argument to complete() when it's called
- * @actual_length: how many bytes were transferd
+ * @actual_length: the total number of bytes that were transferred in all
+ * successful segments
* @status: zero for success, else negative errno
* @queue: for use by whichever driver currently owns the message
* @state: for use by whichever driver currently owns the message
@@ -295,7 +318,7 @@
*
* Some controller drivers (message-at-a-time queue processing)
* could provide that as their default scheduling algorithm. But
- * others (with multi-message pipelines) would need a flag to
+ * others (with multi-message pipelines) could need a flag to
* tell them about such special cases.
*/
@@ -346,6 +369,13 @@
* FIFO order, messages may go to different devices in other orders.
* Some device might be higher priority, or have various "hard" access
* time requirements, for example.
+ *
+ * On detection of any fault during the transfer, processing of
+ * the entire message is aborted, and the device is deselected.
+ * Until returning from the associated message completion callback,
+ * no other spi_message queued to that device will be processed.
+ * (This rule applies equally to all the synchronous transfer calls,
+ * which are wrappers around this core asynchronous primitive.)
*/
static inline int
spi_async(struct spi_device *spi, struct spi_message *message)
@@ -484,12 +514,12 @@
* "modalias" is normally the driver name.
*
* platform_data goes to spi_device.dev.platform_data,
- * controller_data goes to spi_device.platform_data,
+ * controller_data goes to spi_device.controller_data,
* irq is copied too
*/
char modalias[KOBJ_NAME_LEN];
const void *platform_data;
- const void *controller_data;
+ void *controller_data;
int irq;
/* slower signaling on noisy or low voltage boards */
@@ -525,9 +555,8 @@
/* If you're hotplugging an adapter with devices (parport, usb, etc)
- * use spi_new_device() to describe each device. You can also call
- * spi_unregister_device() to get start making that device vanish,
- * but normally that would be handled by spi_unregister_master().
+ * use spi_new_device() to describe each device. You would then call
+ * spi_unregister_device() to start making that device vanish.
*/
extern struct spi_device *
spi_new_device(struct spi_master *, struct spi_board_info *);