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Added support for dynamic binding of spi device in spidev. #3

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Added support for dynamic binding of spi device in spidev. #3

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e088f3b
Added support for dynamic binding of spi device in spidev.
dgallot Jul 18, 2012
075d29e
Cannot register board info if it is commented out
dgallot Jul 19, 2012
4257ff5
Need to sleep.
dgallot Jul 19, 2012
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8 changes: 6 additions & 2 deletions arch/arm/mach-bcm2708/bcm2708.c
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Original file line number Diff line number Diff line change
Expand Up @@ -500,6 +500,9 @@ static struct platform_device bcm2708_spi_device = {
.resource = bcm2708_spi_resources,
};

/*
* Do not link the spi device by default to spidev, since now spidev support manual binding.

static struct spi_board_info bcm2708_spi_devices[] = {
{
.modalias = "spidev",
Expand All @@ -515,6 +518,7 @@ static struct spi_board_info bcm2708_spi_devices[] = {
.mode = SPI_MODE_0,
}
};
*/

static struct resource bcm2708_bsc0_resources[] = {
{
Expand Down Expand Up @@ -625,8 +629,8 @@ void __init bcm2708_init(void)
system_serial_low = serial;

#ifdef CONFIG_SPI
spi_register_board_info(bcm2708_spi_devices,
ARRAY_SIZE(bcm2708_spi_devices));
// spi_register_board_info(bcm2708_spi_devices,
// ARRAY_SIZE(bcm2708_spi_devices));
#endif
}

Expand Down
181 changes: 180 additions & 1 deletion drivers/spi/spidev.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,9 @@
* Copyright (C) 2006 SWAPP
* Andrea Paterniani <a.paterniani@swapp-eng.it>
* Copyright (C) 2007 David Brownell (simplification, cleanup)
*
*
* Dynamic binding by Dominique Gallot <dga@dgconsulting.be>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
Expand All @@ -20,6 +22,7 @@
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/ioctl.h>
Expand All @@ -34,6 +37,7 @@

#include <linux/spi/spi.h>
#include <linux/spi/spidev.h>
#include <linux/string.h>

#include <asm/uaccess.h>

Expand Down Expand Up @@ -88,9 +92,33 @@ struct spidev_data {
static LIST_HEAD(device_list);
static DEFINE_MUTEX(device_list_lock);

struct added_device_struct {
struct list_head list;
struct spi_device *added_device;
};

static LIST_HEAD(added_device_list);

static unsigned bufsiz = 4096;
static char* binding = NULL;
module_param(bufsiz, uint, S_IRUGO);
module_param(binding, charp, S_IRUGO);
/*
This version of spidev support dynamic binding of spidev.
Allowing to bind this spi bus to this driver dynamicly and set the bus parameter
the format of the binding parameter is
spidev0.1=8,1,200000
where 0.1 will link the device with the CS=0 on the spibus 0
8 is the bus length
1 is the spi mode ( see the value of SPI_MODE_x in this case )
2000000 the bus speed
*/
MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message");
MODULE_PARM_DESC(binding, "binding informations. ex: spidev0.0=8,1,2000000;spidev0.1=8,3,60000000");

#define MODULE_BINDING_FORMAT "spidev%d.%d=%d,%d,%d"



/*-------------------------------------------------------------------------*/

Expand Down Expand Up @@ -571,6 +599,125 @@ static struct class *spidev_class;

/*-------------------------------------------------------------------------*/


static int __init add_device_to_bus(u16 spi_bus, u8 spi_bus_cs, u8 spi_bus_mode, u8 spi_bus_bits, u32 spi_bus_speed)
{
struct spi_master *spi_master;
struct spi_device *spi_device;
struct device *pdev;
char buff[64];
int status = 0;
printk( "add_device_to_bus\n");
spi_master = spi_busnum_to_master(spi_bus);
if (!spi_master) {
printk(KERN_ALERT "spi_busnum_to_master(%d) returned NULL\n",
spi_bus);
printk(KERN_ALERT "Missing spi master bus\n");
return -1;
}

spi_device = spi_alloc_device(spi_master);
if (!spi_device) {
put_device(&spi_master->dev);
printk(KERN_ALERT "spi_alloc_device() failed\n");
return -1;
}

// specify a chip select line
spi_device->chip_select = spi_bus_cs;

// Check whether this SPI bus.cs is already claimed
snprintf(buff, sizeof(buff), "%s.%u",
dev_name(&spi_device->master->dev),
spi_device->chip_select);
printk( "bus_find_device_by_name \n");

pdev = bus_find_device_by_name(spi_device->dev.bus, NULL, buff);
if (pdev) {
// We are not going to use this spi_device, so free it
spi_dev_put(spi_device);
if (pdev->driver && pdev->driver->name ) {
printk( "bus_find_device_by_name - device already attached %s \n", pdev->driver->name );
printk( "bus_find_device_by_name - device already attached NULL \n" );
}
//
//There is already a device configured for this bus.cs combination.
// It's okay if it's us. This happens if we previously loaded then
// unloaded our driver.
// If it is not us, we complain and fail.
//
if (pdev->driver && pdev->driver->name &&
strcmp("spidev", pdev->driver->name)) {
printk(KERN_ALERT
"Driver [%s] already registered for %s\n",
pdev->driver->name, buff);
status = -1;
}

} else {
struct added_device_struct *added;
printk( "bus_find_device_by_name - will do spi_add_device\n");
spi_device->max_speed_hz = spi_bus_speed;

spi_device->mode = spi_bus_mode;
spi_device->bits_per_word = spi_bus_bits;
spi_device->irq = -1;
spi_device->controller_state = NULL;
spi_device->controller_data = NULL;
strlcpy(spi_device->modalias, "spidev", SPI_NAME_SIZE);
status = spi_add_device(spi_device);

if (status < 0) {
spi_dev_put(spi_device);
printk(KERN_ALERT "spi_add_device() failed: %d\n",
status);
}
added = (struct added_device_struct *)kmalloc( sizeof(struct added_device_struct), GFP_KERNEL );
added->added_device = spi_device;
list_add( &added->list, &added_device_list );

printk( "spi_add_device %s\n", spi_device->modalias );
}

put_device(&spi_master->dev);

return status;
}

static int __init add_devices_to_bus(void)
{
int spi_bus;
int spi_bus_cs;
int spi_bus_mode;
int spi_bus_bits;
int spi_bus_speed;

int rs = 0, srs = 0;
char *tmp_binding = kstrdup(binding, GFP_KERNEL);
char *entry;

if (!tmp_binding) {
return -ENOMEM;
}

while ( ( entry = strsep(&tmp_binding, ";") ) ) {
printk("binding = %s\n", entry);
srs = sscanf( entry, MODULE_BINDING_FORMAT, &spi_bus, &spi_bus_cs, &spi_bus_bits, &spi_bus_mode, &spi_bus_speed );
if ( srs == 5 ) {
printk( "rs:%d . bus=%d, cs=%d, bits=%d, mode=%d, speed=%d \n", rs, spi_bus, spi_bus_cs, spi_bus_bits, spi_bus_mode, spi_bus_speed );
rs = add_device_to_bus( spi_bus, spi_bus_cs, spi_bus_mode, spi_bus_bits, spi_bus_speed );
if ( rs != 0 ) {
break;
}
} else {
printk( "Invalid binding format %s\n", entry );
}
}
kfree( tmp_binding );
return rs;
}


static int __devinit spidev_probe(struct spi_device *spi)
{
struct spidev_data *spidev;
Expand Down Expand Up @@ -683,12 +830,44 @@ static int __init spidev_init(void)
class_destroy(spidev_class);
unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
}

status = add_devices_to_bus();
if (status < 0) {
struct list_head *pos, *q;
printk(KERN_ALERT "add_device_to_bus() failed\n");
list_for_each_safe( pos, q, &added_device_list ) {
struct added_device_struct *tmp;
tmp = list_entry( pos, struct added_device_struct, list );
printk("spi_unregister_device\n");
spi_unregister_device(tmp->added_device);
printk("spi_dev_put\n");
spi_dev_put(tmp->added_device);
list_del( pos );
kfree( tmp );
}
class_destroy(spidev_class);
unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
spi_unregister_driver(&spidev_spi_driver);
return status;
}

return status;
}
module_init(spidev_init);

static void __exit spidev_exit(void)
{
struct list_head *pos, *q;
list_for_each_safe( pos, q, &added_device_list ) {
struct added_device_struct *tmp;
tmp = list_entry( pos, struct added_device_struct, list );
printk("spi_unregister_device\n");
spi_unregister_device(tmp->added_device);
printk("spi_dev_put\n");
spi_dev_put(tmp->added_device);
list_del( pos );
kfree( tmp );
}
spi_unregister_driver(&spidev_spi_driver);
class_destroy(spidev_class);
unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
Expand Down