u-boot/drivers/core/lists.c
Stephen Warren 9fdfadf8fc dm: core: allow drivers to refuse to bind
In some cases, drivers may not want to bind to a device. Allow bind() to
return -ENODEV in this case, and don't treat this as an error. This can
be useful in situations where some information source other than the DT
node's main status property indicates whether the device should be
enabled, for example other DT properties might indicate this, or the
driver might query non-DT sources such as system fuses or a version number
register.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2016-05-17 09:54:43 -06:00

198 lines
4.7 KiB
C

/*
* Copyright (c) 2013 Google, Inc
*
* (C) Copyright 2012
* Marek Vasut <marex@denx.de>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <errno.h>
#include <dm/device.h>
#include <dm/device-internal.h>
#include <dm/lists.h>
#include <dm/platdata.h>
#include <dm/uclass.h>
#include <dm/util.h>
#include <fdtdec.h>
#include <linux/compiler.h>
struct driver *lists_driver_lookup_name(const char *name)
{
struct driver *drv =
ll_entry_start(struct driver, driver);
const int n_ents = ll_entry_count(struct driver, driver);
struct driver *entry;
for (entry = drv; entry != drv + n_ents; entry++) {
if (!strcmp(name, entry->name))
return entry;
}
/* Not found */
return NULL;
}
struct uclass_driver *lists_uclass_lookup(enum uclass_id id)
{
struct uclass_driver *uclass =
ll_entry_start(struct uclass_driver, uclass);
const int n_ents = ll_entry_count(struct uclass_driver, uclass);
struct uclass_driver *entry;
for (entry = uclass; entry != uclass + n_ents; entry++) {
if (entry->id == id)
return entry;
}
return NULL;
}
int lists_bind_drivers(struct udevice *parent, bool pre_reloc_only)
{
struct driver_info *info =
ll_entry_start(struct driver_info, driver_info);
const int n_ents = ll_entry_count(struct driver_info, driver_info);
struct driver_info *entry;
struct udevice *dev;
int result = 0;
int ret;
for (entry = info; entry != info + n_ents; entry++) {
ret = device_bind_by_name(parent, pre_reloc_only, entry, &dev);
if (ret && ret != -EPERM) {
dm_warn("No match for driver '%s'\n", entry->name);
if (!result || ret != -ENOENT)
result = ret;
}
}
return result;
}
int device_bind_driver(struct udevice *parent, const char *drv_name,
const char *dev_name, struct udevice **devp)
{
return device_bind_driver_to_node(parent, drv_name, dev_name, -1, devp);
}
int device_bind_driver_to_node(struct udevice *parent, const char *drv_name,
const char *dev_name, int node,
struct udevice **devp)
{
struct driver *drv;
int ret;
drv = lists_driver_lookup_name(drv_name);
if (!drv) {
debug("Cannot find driver '%s'\n", drv_name);
return -ENOENT;
}
ret = device_bind(parent, drv, dev_name, NULL, node, devp);
if (ret) {
debug("Cannot create device named '%s' (err=%d)\n",
dev_name, ret);
return ret;
}
return 0;
}
#if CONFIG_IS_ENABLED(OF_CONTROL)
/**
* driver_check_compatible() - Check if a driver is compatible with this node
*
* @param blob: Device tree pointer
* @param offset: Offset of node in device tree
* @param of_match: List of compatible strings to match
* @param of_idp: Returns the match that was found
* @return 0 if there is a match, -ENOENT if no match, -ENODEV if the node
* does not have a compatible string, other error <0 if there is a device
* tree error
*/
static int driver_check_compatible(const void *blob, int offset,
const struct udevice_id *of_match,
const struct udevice_id **of_idp)
{
int ret;
*of_idp = NULL;
if (!of_match)
return -ENOENT;
while (of_match->compatible) {
ret = fdt_node_check_compatible(blob, offset,
of_match->compatible);
if (!ret) {
*of_idp = of_match;
return 0;
} else if (ret == -FDT_ERR_NOTFOUND) {
return -ENODEV;
} else if (ret < 0) {
return -EINVAL;
}
of_match++;
}
return -ENOENT;
}
int lists_bind_fdt(struct udevice *parent, const void *blob, int offset,
struct udevice **devp)
{
struct driver *driver = ll_entry_start(struct driver, driver);
const int n_ents = ll_entry_count(struct driver, driver);
const struct udevice_id *id;
struct driver *entry;
struct udevice *dev;
bool found = false;
const char *name;
int result = 0;
int ret = 0;
dm_dbg("bind node %s\n", fdt_get_name(blob, offset, NULL));
if (devp)
*devp = NULL;
for (entry = driver; entry != driver + n_ents; entry++) {
ret = driver_check_compatible(blob, offset, entry->of_match,
&id);
name = fdt_get_name(blob, offset, NULL);
if (ret == -ENOENT) {
continue;
} else if (ret == -ENODEV) {
dm_dbg("Device '%s' has no compatible string\n", name);
break;
} else if (ret) {
dm_warn("Device tree error at offset %d\n", offset);
result = ret;
break;
}
dm_dbg(" - found match at '%s'\n", entry->name);
ret = device_bind(parent, entry, name, NULL, offset, &dev);
if (ret == -ENODEV) {
dm_dbg("Driver '%s' refuses to bind\n", entry->name);
continue;
}
if (ret) {
dm_warn("Error binding driver '%s': %d\n", entry->name,
ret);
return ret;
} else {
dev->driver_data = id->data;
found = true;
if (devp)
*devp = dev;
}
break;
}
if (!found && !result && ret != -ENODEV) {
dm_dbg("No match for node '%s'\n",
fdt_get_name(blob, offset, NULL));
}
return result;
}
#endif