[PATCH v2 11/14] i2c/of: Factor out Devicetree registration code

[PATCH v2 11/14] i2c/of: Factor out Devicetree registration code

[Grant Likely]

From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>

Dynamically inserting i2c client device nodes requires the use
of a single device registration method. Factor out the loop body of
of_i2c_register_devices() so that it can be called for individual
device_nodes instead of for all the children of a node.

Note: The diff of this commit looks far more complicated than it
actually is due the indentation being changed for a large block of code.
When viewed using the diff -w flag to ignore whitespace changes it can
be seen that the change is actually quite simple.

Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
[grant.likely: Made new function static and removed changes to header]
Signed-off-by: Grant Likely <grant.likely@linaro.org>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-i2c@vger.kernel.org
---
 drivers/i2c/i2c-core.c | 97 +++++++++++++++++++++++++++-----------------------
 1 file changed, 52 insertions(+), 45 deletions(-)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index f43b4e11647a..15ba6185dba5 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -49,6 +49,7 @@
 #include <linux/acpi.h>
 #include <linux/jump_label.h>
 #include <asm/uaccess.h>
+#include <linux/err.h>
 
 #include "i2c-core.h"
 
@@ -1368,63 +1369,69 @@ static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
 /* OF support code */
 
 #if IS_ENABLED(CONFIG_OF)
-static void of_i2c_register_devices(struct i2c_adapter *adap)
+static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
+						 struct device_node *node)
 {
-	void *result;
-	struct device_node *node;
+	struct i2c_client *result;
+	struct i2c_board_info info = {};
+	struct dev_archdata dev_ad = {};
+	const __be32 *addr;
+	int len;
 
-	/* Only register child devices if the adapter has a node pointer set */
-	if (!adap->dev.of_node)
-		return;
+	dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
 
-	dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
+	if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
+		dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
+			node->full_name);
+		return ERR_PTR(-EINVAL);
+	}
 
-	for_each_available_child_of_node(adap->dev.of_node, node) {
-		struct i2c_board_info info = {};
-		struct dev_archdata dev_ad = {};
-		const __be32 *addr;
-		int len;
+	addr = of_get_property(node, "reg", &len);
+	if (!addr || (len < sizeof(int))) {
+		dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
+			node->full_name);
+		return ERR_PTR(-EINVAL);
+	}
 
-		dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
+	info.addr = be32_to_cpup(addr);
+	if (info.addr > (1 << 10) - 1) {
+		dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
+			info.addr, node->full_name);
+		return ERR_PTR(-EINVAL);
+	}
 
-		if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
-			dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
-				node->full_name);
-			continue;
-		}
+	info.irq = irq_of_parse_and_map(node, 0);
+	info.of_node = of_node_get(node);
+	info.archdata = &dev_ad;
 
-		addr = of_get_property(node, "reg", &len);
-		if (!addr || (len < sizeof(int))) {
-			dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
-				node->full_name);
-			continue;
-		}
+	if (of_get_property(node, "wakeup-source", NULL))
+		info.flags |= I2C_CLIENT_WAKE;
 
-		info.addr = be32_to_cpup(addr);
-		if (info.addr > (1 << 10) - 1) {
-			dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
-				info.addr, node->full_name);
-			continue;
-		}
+	request_module("%s%s", I2C_MODULE_PREFIX, info.type);
 
-		info.irq = irq_of_parse_and_map(node, 0);
-		info.of_node = of_node_get(node);
-		info.archdata = &dev_ad;
+	result = i2c_new_device(adap, &info);
+	if (result == NULL) {
+		dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
+			node->full_name);
+		of_node_put(node);
+		irq_dispose_mapping(info.irq);
+		return ERR_PTR(-EINVAL);
+	}
+	return result;
+}
 
-		if (of_get_property(node, "wakeup-source", NULL))
-			info.flags |= I2C_CLIENT_WAKE;
+static void of_i2c_register_devices(struct i2c_adapter *adap)
+{
+	struct device_node *node;
 
-		request_module("%s%s", I2C_MODULE_PREFIX, info.type);
+	/* Only register child devices if the adapter has a node pointer set */
+	if (!adap->dev.of_node)
+		return;
 
-		result = i2c_new_device(adap, &info);
-		if (result == NULL) {
-			dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
-				node->full_name);
-			of_node_put(node);
-			irq_dispose_mapping(info.irq);
-			continue;
-		}
-	}
+	dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
+
+	for_each_available_child_of_node(adap->dev.of_node, node)
+		of_i2c_register_device(adap, node);
 }
 
 static int of_dev_node_match(struct device *dev, void *data)
-- 
1.9.1

[PATCH v2 12/14] i2c/of: Add OF_RECONFIG notifier handler

[Grant Likely]

From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>

CONFIG_OF_DYNAMIC enables runtime changes to the device tree which in
turn may trigger addition or removal of devices from Linux. Add an
OF_RECONFIG notifier handler to receive tree change events and to
creating or destroy i2c devices as required.

Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
[grant.likely: clean up #ifdefs and drop unneeded error handling]
Signed-off-by: Grant Likely <grant.likely@linaro.org>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-i2c@vger.kernel.org
---
 drivers/i2c/i2c-core.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 15ba6185dba5..d8afd3f28ca4 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1951,6 +1951,52 @@ void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
 }
 EXPORT_SYMBOL(i2c_clients_command);
 
+#if IS_ENABLED(CONFIG_OF_DYNAMIC)
+static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
+			 void *arg)
+{
+	struct of_reconfig_data *rd = arg;
+	struct i2c_adapter *adap;
+	struct i2c_client *client;
+
+	switch (of_reconfig_get_state_change(action, rd)) {
+	case OF_RECONFIG_CHANGE_ADD:
+		adap = of_find_i2c_adapter_by_node(rd->dn->parent);
+		if (adap == NULL)
+			return NOTIFY_OK;	/* not for us */
+
+		client = of_i2c_register_device(adap, rd->dn);
+		put_device(&adap->dev);
+
+		if (IS_ERR(client)) {
+			pr_err("%s: failed to create for '%s'\n",
+					__func__, rd->dn->full_name);
+			return notifier_from_errno(PTR_ERR(client));
+		}
+		break;
+	case OF_RECONFIG_CHANGE_REMOVE:
+		/* find our device by node */
+		client = of_find_i2c_device_by_node(rd->dn);
+		if (client == NULL)
+			return NOTIFY_OK;	/* no? not meant for us */
+
+		/* unregister takes one ref away */
+		i2c_unregister_device(client);
+
+		/* and put the reference of the find */
+		put_device(&client->dev);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+static struct notifier_block i2c_of_notifier = {
+	.notifier_call = of_i2c_notify,
+};
+#else
+extern struct notifier_block i2c_of_notifier;
+#endif /* CONFIG_OF_DYNAMIC */
+
 static int __init i2c_init(void)
 {
 	int retval;
@@ -1968,6 +2014,10 @@ static int __init i2c_init(void)
 	retval = i2c_add_driver(&dummy_driver);
 	if (retval)
 		goto class_err;
+
+	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
+		WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
+
 	return 0;
 
 class_err:
@@ -1981,6 +2031,8 @@ bus_err:
 
 static void __exit i2c_exit(void)
 {
+	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
+		WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
 	i2c_del_driver(&dummy_driver);
 #ifdef CONFIG_I2C_COMPAT
 	class_compat_unregister(i2c_adapter_compat_class);
-- 
1.9.1

Re: [PATCH v2 11/14] i2c/of: Factor out Devicetree registration code

[Wolfram Sang]

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On Mon, Nov 24, 2014 at 10:33:39PM +0000, Grant Likely wrote:
> From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> 
> Dynamically inserting i2c client device nodes requires the use
> of a single device registration method. Factor out the loop body of
> of_i2c_register_devices() so that it can be called for individual
> device_nodes instead of for all the children of a node.
> 
> Note: The diff of this commit looks far more complicated than it
> actually is due the indentation being changed for a large block of code.
> When viewed using the diff -w flag to ignore whitespace changes it can
> be seen that the change is actually quite simple.
> 
> Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> [grant.likely: Made new function static and removed changes to header]
> Signed-off-by: Grant Likely <grant.likely@linaro.org>
> Cc: Wolfram Sang <wsa@the-dreams.de>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: linux-i2c@vger.kernel.org

Reviewed-by: Wolfram Sang <wsa@the-dreams.de>

I'd prefer that this series goes through your tree. There is still this
merge conflict, but that is an easy one like I mentioned in my last
review.

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Re: [PATCH v2 12/14] i2c/of: Add OF_RECONFIG notifier handler

[Wolfram Sang]

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On Mon, Nov 24, 2014 at 10:33:40PM +0000, Grant Likely wrote:
> From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> 
> CONFIG_OF_DYNAMIC enables runtime changes to the device tree which in
> turn may trigger addition or removal of devices from Linux. Add an
> OF_RECONFIG notifier handler to receive tree change events and to
> creating or destroy i2c devices as required.
> 
> Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> [grant.likely: clean up #ifdefs and drop unneeded error handling]
> Signed-off-by: Grant Likely <grant.likely@linaro.org>
> Cc: Wolfram Sang <wsa@the-dreams.de>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: linux-i2c@vger.kernel.org

Reviewed-by: Wolfram Sang <wsa@the-dreams.de>


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