Commit 2b9603a0 authored by Feng Tang's avatar Feng Tang Committed by Grant Likely
Browse files

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: default avatarFeng Tang <feng.tang@intel.com>
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
parent d4429f60

drivers/spi/spi.c

+47 −41
Original line number Diff line number Diff line
@@ -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 @@ 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);



/**
@@ -371,6 +371,20 @@ 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);

}



/**

 * spi_register_board_info - register SPI devices for a given board

 * @info: array of chip descriptors
@@ -394,42 +408,24 @@ int __init 
spi_register_board_info(struct spi_board_info const *info, unsigned n)

{

	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);



	for (i = 0; i < n; i++, bi++, info++) {

		struct spi_master *master;



		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);

	return 0;

	}



/* 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);

		}

	}

	mutex_unlock(&board_lock);

	return 0;

}



/*-------------------------------------------------------------------------*/
@@ -512,6 +508,7 @@ int spi_register_master(struct spi_master *master) 
{

	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 @@ 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 */

	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 @@ void spi_unregister_master(struct spi_master *master) 
{

	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);

include/linux/spi/spi.h

+3 −0
Original line number Diff line number Diff line
@@ -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
@@ -238,6 +239,8 @@ 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,

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