[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/drivers/spi/spi.c b/drivers/spi/spi.c
index 7cd356b..2ecb86c 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -26,13 +26,9 @@
#include <linux/spi/spi.h>
-/* SPI bustype and spi_master class are registered during early boot,
- * usually before board init code provides the SPI device tables, and
- * are available later when driver init code needs them.
- *
- * Drivers for SPI devices started out like those for platform bus
- * devices. But both have changed in 2.6.15; maybe this should get
- * an "spi_driver" structure at some point (not currently needed)
+/* SPI bustype and spi_master class are registered after board init code
+ * provides the SPI device tables, ensuring that both are present by the
+ * time controller driver registration causes spi_devices to "enumerate".
*/
static void spidev_release(struct device *dev)
{
@@ -83,10 +79,7 @@
#ifdef CONFIG_PM
-/* Suspend/resume in "struct device_driver" don't really need that
- * strange third parameter, so we just make it a constant and expect
- * SPI drivers to ignore it just like most platform drivers do.
- *
+/*
* NOTE: the suspend() method for an spi_master controller driver
* should verify that all its child devices are marked as suspended;
* suspend requests delivered through sysfs power/state files don't
@@ -94,13 +87,14 @@
*/
static int spi_suspend(struct device *dev, pm_message_t message)
{
- int value;
+ int value;
+ struct spi_driver *drv = to_spi_driver(dev->driver);
- if (!dev->driver || !dev->driver->suspend)
+ if (!drv || !drv->suspend)
return 0;
/* suspend will stop irqs and dma; no more i/o */
- value = dev->driver->suspend(dev, message);
+ value = drv->suspend(to_spi_device(dev), message);
if (value == 0)
dev->power.power_state = message;
return value;
@@ -108,13 +102,14 @@
static int spi_resume(struct device *dev)
{
- int value;
+ int value;
+ struct spi_driver *drv = to_spi_driver(dev->driver);
- if (!dev->driver || !dev->driver->resume)
+ if (!drv || !drv->resume)
return 0;
/* resume may restart the i/o queue */
- value = dev->driver->resume(dev);
+ value = drv->resume(to_spi_device(dev));
if (value == 0)
dev->power.power_state = PMSG_ON;
return value;
@@ -135,6 +130,41 @@
};
EXPORT_SYMBOL_GPL(spi_bus_type);
+
+static int spi_drv_probe(struct device *dev)
+{
+ const struct spi_driver *sdrv = to_spi_driver(dev->driver);
+
+ return sdrv->probe(to_spi_device(dev));
+}
+
+static int spi_drv_remove(struct device *dev)
+{
+ const struct spi_driver *sdrv = to_spi_driver(dev->driver);
+
+ return sdrv->remove(to_spi_device(dev));
+}
+
+static void spi_drv_shutdown(struct device *dev)
+{
+ const struct spi_driver *sdrv = to_spi_driver(dev->driver);
+
+ sdrv->shutdown(to_spi_device(dev));
+}
+
+int spi_register_driver(struct spi_driver *sdrv)
+{
+ sdrv->driver.bus = &spi_bus_type;
+ if (sdrv->probe)
+ sdrv->driver.probe = spi_drv_probe;
+ if (sdrv->remove)
+ sdrv->driver.remove = spi_drv_remove;
+ if (sdrv->shutdown)
+ sdrv->driver.shutdown = spi_drv_shutdown;
+ return driver_register(&sdrv->driver);
+}
+EXPORT_SYMBOL_GPL(spi_register_driver);
+
/*-------------------------------------------------------------------------*/
/* SPI devices should normally not be created by SPI device drivers; that
@@ -208,13 +238,15 @@
if (status < 0) {
dev_dbg(dev, "can't %s %s, status %d\n",
"add", proxy->dev.bus_id, status);
-fail:
- class_device_put(&master->cdev);
- kfree(proxy);
- return NULL;
+ goto fail;
}
dev_dbg(dev, "registered child %s\n", proxy->dev.bus_id);
return proxy;
+
+fail:
+ class_device_put(&master->cdev);
+ kfree(proxy);
+ return NULL;
}
EXPORT_SYMBOL_GPL(spi_new_device);
@@ -237,11 +269,11 @@
{
struct boardinfo *bi;
- bi = kmalloc (sizeof (*bi) + n * sizeof (*info), GFP_KERNEL);
+ bi = kmalloc(sizeof(*bi) + n * sizeof *info, GFP_KERNEL);
if (!bi)
return -ENOMEM;
bi->n_board_info = n;
- memcpy(bi->board_info, info, n * sizeof (*info));
+ memcpy(bi->board_info, info, n * sizeof *info);
down(&board_lock);
list_add_tail(&bi->list, &board_list);
@@ -330,6 +362,7 @@
if (!master)
return NULL;
+ class_device_initialize(&master->cdev);
master->cdev.class = &spi_master_class;
master->cdev.dev = get_device(dev);
class_set_devdata(&master->cdev, &master[1]);
@@ -366,7 +399,7 @@
/* convention: dynamically assigned bus IDs count down from the max */
if (master->bus_num == 0) {
master->bus_num = atomic_dec_return(&dyn_bus_id);
- dynamic = 0;
+ dynamic = 1;
}
/* register the device, then userspace will see it.
@@ -374,11 +407,9 @@
*/
snprintf(master->cdev.class_id, sizeof master->cdev.class_id,
"spi%u", master->bus_num);
- status = class_device_register(&master->cdev);
- if (status < 0) {
- class_device_put(&master->cdev);
+ status = class_device_add(&master->cdev);
+ if (status < 0)
goto done;
- }
dev_dbg(dev, "registered master %s%s\n", master->cdev.class_id,
dynamic ? " (dynamic)" : "");
@@ -491,6 +522,7 @@
* This performs a half duplex MicroWire style transaction with the
* device, sending txbuf and then reading rxbuf. The return value
* is zero for success, else a negative errno status code.
+ * This call may only be used from a context that may sleep.
*
* Parameters to this routine are always copied using a small buffer,
* large transfers should use use spi_{async,sync}() calls with
@@ -553,16 +585,38 @@
static int __init spi_init(void)
{
- buf = kmalloc(SPI_BUFSIZ, SLAB_KERNEL);
- if (!buf)
- return -ENOMEM;
+ int status;
- bus_register(&spi_bus_type);
- class_register(&spi_master_class);
+ buf = kmalloc(SPI_BUFSIZ, SLAB_KERNEL);
+ if (!buf) {
+ status = -ENOMEM;
+ goto err0;
+ }
+
+ status = bus_register(&spi_bus_type);
+ if (status < 0)
+ goto err1;
+
+ status = class_register(&spi_master_class);
+ if (status < 0)
+ goto err2;
return 0;
+
+err2:
+ bus_unregister(&spi_bus_type);
+err1:
+ kfree(buf);
+ buf = NULL;
+err0:
+ return status;
}
+
/* board_info is normally registered in arch_initcall(),
* but even essential drivers wait till later
+ *
+ * REVISIT only boardinfo really needs static linking. the rest (device and
+ * driver registration) _could_ be dynamically linked (modular) ... costs
+ * include needing to have boardinfo data structures be much more public.
*/
subsys_initcall(spi_init);