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[PATCH] spi: add spi_driver to SPI framework

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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>
This commit is contained in:
David Brownell
2006-01-08 13:34:23 -08:00
committed by Greg Kroah-Hartman
parent 1d6432fe10
commit b885244eb2
3 changed files with 171 additions and 76 deletions
Download Patch File Download Diff File Expand all files Collapse all files

75
include/linux/spi/spi.h
View File

@ -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 @@ extern struct bus_type spi_bus_type;
* @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 @@ struct spi_device {
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 @@ static inline void spi_set_ctldata(struct spi_device *spi, void *state)
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 @@ struct spi_transfer {
* 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 @@ struct spi_message {
*
* 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 @@ spi_setup(struct spi_device *spi)
* 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 @@ struct spi_board_info {
* "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 @@ spi_register_board_info(struct spi_board_info const *info, unsigned n)
/* 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 *);