[PATCH v2 13/16] bus: vexpress-config: simplify config bus probing

Rob Herring
2020-04-29T20:58:50Z

The vexpress-config initialization is dependent on the vexpress-syscfg
driver probing. As vexpress-config was not a driver, deferred probe
could not be used and instead initcall ordering was relied upon. This is
fragile and doesn't work for modules.

Let's move the config bus init into the vexpress-syscfg probe. This
eliminates the initcall ordering requirement and the need to create a
struct device and the "vexpress-config" class.

Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Rob Herring <robh@kernel.org>
---
drivers/bus/vexpress-config.c | 118 ++++++----------------------------
1 file changed, 21 insertions(+), 97 deletions(-)

diff --git a/drivers/bus/vexpress-config.c b/drivers/bus/vexpress-config.c
index 43f5beac9811..43deb4df140b 100644
--- a/drivers/bus/vexpress-config.c
+++ b/drivers/bus/vexpress-config.c
@@ -56,7 +56,6 @@ struct vexpress_config_bridge {

static DEFINE_MUTEX(vexpress_config_mutex);
-static struct class *vexpress_config_class;
static u32 vexpress_config_site_master = VEXPRESS_SITE_MASTER;

@@ -121,9 +120,6 @@ struct regmap *devm_regmap_init_vexpress_config(struct device *dev)
struct regmap *regmap;
struct regmap **res;

- if (WARN_ON(dev->parent->class != vexpress_config_class))
- return ERR_PTR(-ENODEV);
-
bridge = dev_get_drvdata(dev->parent);
if (WARN_ON(!bridge))
return ERR_PTR(-EINVAL);
@@ -146,94 +142,6 @@ struct regmap *devm_regmap_init_vexpress_config(struct device *dev)
}
EXPORT_SYMBOL_GPL(devm_regmap_init_vexpress_config);

-static struct device *vexpress_config_bridge_register(struct device *parent,
- struct vexpress_config_bridge_ops *ops, void *context)
-{
- struct device *dev;
- struct vexpress_config_bridge *bridge;
-
- if (!vexpress_config_class) {
- vexpress_config_class = class_create(THIS_MODULE,
- "vexpress-config");
- if (IS_ERR(vexpress_config_class))
- return (void *)vexpress_config_class;
- }
-
- dev = device_create(vexpress_config_class, parent, 0,
- NULL, "%s.bridge", dev_name(parent));
-
- if (IS_ERR(dev))
- return dev;
-
- bridge = devm_kmalloc(dev, sizeof(*bridge), GFP_KERNEL);
- if (!bridge) {
- put_device(dev);
- device_unregister(dev);
- return ERR_PTR(-ENOMEM);
- }
- bridge->ops = ops;
- bridge->context = context;
-
- dev_set_drvdata(dev, bridge);
-
- dev_dbg(parent, "Registered bridge '%s', parent node %p\n",
- dev_name(dev), parent->of_node);
-
- return dev;
-}
-
-
-static int vexpress_config_node_match(struct device *dev, const void *data)
-{
- const struct device_node *node = data;
-
- dev_dbg(dev, "Parent node %p, looking for %p\n",
- dev->parent->of_node, node);
-
- return dev->parent->of_node == node;
-}
-
-static int vexpress_config_populate(struct device_node *node)
-{
- struct device_node *bridge;
- struct device *parent;
- int ret;
-
- bridge = of_parse_phandle(node, "arm,vexpress,config-bridge", 0);
- if (!bridge)
- return -EINVAL;
-
- parent = class_find_device(vexpress_config_class, NULL, bridge,
- vexpress_config_node_match);
- of_node_put(bridge);
- if (WARN_ON(!parent))
- return -ENODEV;
-
- ret = of_platform_populate(node, NULL, NULL, parent);
-
- put_device(parent);
-
- return ret;
-}
-
-static int __init vexpress_config_init(void)
-{
- int err = 0;
- struct device_node *node;
-
- /* Need the config devices early, before the "normal" devices... */
- for_each_compatible_node(node, NULL, "arm,vexpress,config-bus") {
- err = vexpress_config_populate(node);
- if (err) {
- of_node_put(node);
- break;
- }
- }
-
- return err;
-}
-postcore_initcall(vexpress_config_init);
-
static int vexpress_syscfg_exec(struct vexpress_syscfg_func *func,
int index, bool write, u32 *data)
{
@@ -430,7 +338,8 @@ static int vexpress_syscfg_probe(struct platform_device *pdev)
{
struct vexpress_syscfg *syscfg;
struct resource *res;
- struct device *bridge;
+ struct vexpress_config_bridge *bridge;
+ struct device_node *node;

syscfg = devm_kzalloc(&pdev->dev, sizeof(*syscfg), GFP_KERNEL);
if (!syscfg)
@@ -443,11 +352,26 @@ static int vexpress_syscfg_probe(struct platform_device *pdev)
if (IS_ERR(syscfg->base))
return PTR_ERR(syscfg->base);

- /* Must use dev.parent (MFD), as that's where DT phandle points at... */
- bridge = vexpress_config_bridge_register(pdev->dev.parent,
- &vexpress_syscfg_bridge_ops, syscfg);
+ bridge = devm_kmalloc(&pdev->dev, sizeof(*bridge), GFP_KERNEL);
+ if (!bridge)
+ return -ENOMEM;
+
+ bridge->ops = &vexpress_syscfg_bridge_ops;
+ bridge->context = syscfg;
+
+ dev_set_drvdata(&pdev->dev, bridge);

- return PTR_ERR_OR_ZERO(bridge);
+ for_each_compatible_node(node, NULL, "arm,vexpress,config-bus") {
+ struct device_node *bridge_np;
+
+ bridge_np = of_parse_phandle(node, "arm,vexpress,config-bridge", 0);
+ if (bridge_np != pdev->dev.parent->of_node)
+ continue;
+
+ of_platform_populate(node, NULL, NULL, &pdev->dev);
+ }
+
+ return 0;
}

static const struct platform_device_id vexpress_syscfg_id_table[] = {
--
2.20.1