spi: enable spi_board_info to be registered after spi_master
Currently spi_register_board_info() has to be called before its related
spi_master be registered, otherwise these board info will be just ignored.
This patch will remove this order limit, it adds a global spi master list
like the existing global board info listr. Whenever a board info or a
spi_master is registered, the spi master list or board info list
will be scanned, and a new spi device will be created if there is a
master-board info match.
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index b5a78a1..0845cd4 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -29,11 +29,6 @@
#include <linux/spi/spi.h>
#include <linux/of_spi.h>
-
-/* 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)
{
struct spi_device *spi = to_spi_device(dev);
@@ -202,11 +197,16 @@
struct boardinfo {
struct list_head list;
- unsigned n_board_info;
- struct spi_board_info board_info[0];
+ struct spi_board_info board_info;
};
static LIST_HEAD(board_list);
+static LIST_HEAD(spi_master_list);
+
+/*
+ * Used to protect add/del opertion for board_info list and
+ * spi_master list, and their matching process
+ */
static DEFINE_MUTEX(board_lock);
/**
@@ -371,6 +371,20 @@
}
EXPORT_SYMBOL_GPL(spi_new_device);
+static void spi_match_master_to_boardinfo(struct spi_master *master,
+ struct spi_board_info *bi)
+{
+ struct spi_device *dev;
+
+ if (master->bus_num != bi->bus_num)
+ return;
+
+ dev = spi_new_device(master, bi);
+ if (!dev)
+ dev_err(master->dev.parent, "can't create new device for %s\n",
+ bi->modalias);
+}
+
/**
* spi_register_board_info - register SPI devices for a given board
* @info: array of chip descriptors
@@ -393,43 +407,25 @@
int __init
spi_register_board_info(struct spi_board_info const *info, unsigned n)
{
- struct boardinfo *bi;
+ struct boardinfo *bi;
+ int i;
- bi = kmalloc(sizeof(*bi) + n * sizeof *info, GFP_KERNEL);
+ bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
if (!bi)
return -ENOMEM;
- bi->n_board_info = n;
- memcpy(bi->board_info, info, n * sizeof *info);
- mutex_lock(&board_lock);
- list_add_tail(&bi->list, &board_list);
- mutex_unlock(&board_lock);
- return 0;
-}
+ for (i = 0; i < n; i++, bi++, info++) {
+ struct spi_master *master;
-/* FIXME someone should add support for a __setup("spi", ...) that
- * creates board info from kernel command lines
- */
-
-static void scan_boardinfo(struct spi_master *master)
-{
- struct boardinfo *bi;
-
- mutex_lock(&board_lock);
- list_for_each_entry(bi, &board_list, list) {
- struct spi_board_info *chip = bi->board_info;
- unsigned n;
-
- for (n = bi->n_board_info; n > 0; n--, chip++) {
- if (chip->bus_num != master->bus_num)
- continue;
- /* NOTE: this relies on spi_new_device to
- * issue diagnostics when given bogus inputs
- */
- (void) spi_new_device(master, chip);
- }
+ memcpy(&bi->board_info, info, sizeof(*info));
+ mutex_lock(&board_lock);
+ list_add_tail(&bi->list, &board_list);
+ list_for_each_entry(master, &spi_master_list, list)
+ spi_match_master_to_boardinfo(master, &bi->board_info);
+ mutex_unlock(&board_lock);
}
- mutex_unlock(&board_lock);
+
+ return 0;
}
/*-------------------------------------------------------------------------*/
@@ -512,6 +508,7 @@
{
static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
struct device *dev = master->dev.parent;
+ struct boardinfo *bi;
int status = -ENODEV;
int dynamic = 0;
@@ -547,8 +544,12 @@
dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
dynamic ? " (dynamic)" : "");
- /* populate children from any spi device tables */
- scan_boardinfo(master);
+ mutex_lock(&board_lock);
+ list_add_tail(&master->list, &spi_master_list);
+ list_for_each_entry(bi, &board_list, list)
+ spi_match_master_to_boardinfo(master, &bi->board_info);
+ mutex_unlock(&board_lock);
+
status = 0;
/* Register devices from the device tree */
@@ -579,7 +580,12 @@
{
int dummy;
- dummy = device_for_each_child(&master->dev, NULL, __unregister);
+ mutex_lock(&board_lock);
+ list_del(&master->list);
+ mutex_unlock(&board_lock);
+
+ dummy = device_for_each_child(master->dev.parent, &master->dev,
+ __unregister);
device_unregister(&master->dev);
}
EXPORT_SYMBOL_GPL(spi_unregister_master);
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 92e52a1..b4d7710 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -204,6 +204,7 @@
/**
* struct spi_master - interface to SPI master controller
* @dev: device interface to this driver
+ * @list: link with the global spi_master list
* @bus_num: board-specific (and often SOC-specific) identifier for a
* given SPI controller.
* @num_chipselect: chipselects are used to distinguish individual
@@ -238,6 +239,8 @@
struct spi_master {
struct device dev;
+ struct list_head list;
+
/* other than negative (== assign one dynamically), bus_num is fully
* board-specific. usually that simplifies to being SOC-specific.
* example: one SOC has three SPI controllers, numbered 0..2,