Hi All,
Pls review this patch. thanks,
-Feng
Changelog:
v4:
* Abstract a spi_match_master_to_boardinfo() which will
be called in scanning master/boardinfo list, suggested
by Grant also.
v3:
* As suggested by Grant, use one lock to protect the match
between spi_master and spi board info
v2:
* fix a typo in looping scan_masterlist()
* fix one race condition found by Grant
>From 799ff94edc90117afdbba223fb35cb36a1d2b4b4 Mon Sep 17 00:00:00 2001
From: Feng Tang <feng.t...@intel.com>
Date: Tue, 27 Jul 2010 17:15:05 +0800
Subject: [PATCH] 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.
Cc: David Brownell <dbrown...@users.sourceforge.net>
Cc: Grant Likely <grant.lik...@secretlab.ca>
Signed-off-by: Feng Tang <feng.t...@intel.com>
---
drivers/spi/spi.c | 86 +++++++++++++++++++++++++++++++----------------
include/linux/spi/spi.h | 3 ++
2 files changed, 60 insertions(+), 29 deletions(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index b3a1f92..70fb141 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -196,11 +196,16 @@ EXPORT_SYMBOL_GPL(spi_register_driver);
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);
/**
@@ -365,6 +370,30 @@ struct spi_device *spi_new_device(struct spi_master
*master,
}
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);
+}
+
+
+/* Has to be called when board_lock is acquired */
+static void spi_scan_masterlist(struct spi_board_info *bi)
+{
+ struct spi_master *master;
+
+ list_for_each_entry(master, &spi_master_list, list)
+ spi_match_master_to_boardinfo(master, bi);
+}
+
/**
* spi_register_board_info - register SPI devices for a given board
* @info: array of chip descriptors
@@ -387,43 +416,36 @@ EXPORT_SYMBOL_GPL(spi_new_device);
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);
+ for (i = 0; i < n; i++, bi++, info++) {
+ memcpy(&bi->board_info, info, sizeof(*info));
+ mutex_lock(&board_lock);
+ list_add_tail(&bi->list, &board_list);
+ spi_scan_masterlist(&bi->board_info);
+ mutex_unlock(&board_lock);
+ }
+
return 0;
}
-/* FIXME someone should add support for a __setup("spi", ...) that
+/*
+ * FIXME someone should add support for a __setup("spi", ...) that
* creates board info from kernel command lines
+ *
+ * Should be called when board_lock is acquired
*/
-
static void scan_boardinfo(struct spi_master *master)
{
- struct boardinfo *bi;
+ 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);
- }
- }
- mutex_unlock(&board_lock);
+ list_for_each_entry(bi, &board_list, list)
+ spi_match_master_to_boardinfo(master, &bi->board_info);
}
/*-------------------------------------------------------------------------*/
@@ -537,15 +559,17 @@ int spi_register_master(struct spi_master *master)
dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
dynamic ? " (dynamic)" : "");
- /* populate children from any spi device tables */
+ mutex_lock(&board_lock);
+ list_add_tail(&master->list, &spi_master_list);
scan_boardinfo(master);
+ mutex_unlock(&board_lock);
+
status = 0;
done:
return status;
}
EXPORT_SYMBOL_GPL(spi_register_master);
-
static int __unregister(struct device *dev, void *master_dev)
{
/* note: before about 2.6.14-rc1 this would corrupt memory: */
@@ -568,6 +592,10 @@ void spi_unregister_master(struct spi_master *master)
{
int dummy;
+ 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);
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index af56071..f4a29b6 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -204,6 +204,7 @@ static inline void spi_unregister_driver(struct spi_driver
*sdrv)
/**
* 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
@@ -235,6 +236,8 @@ static inline void spi_unregister_driver(struct spi_driver
*sdrv)
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,
--
1.7.0.4
------------------------------------------------------------------------------
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