[v21,RESEND,1/4] i2c: core: support bus regulator controlling in adapter

Commit Message

Hsin-Yi Wang May 27, 2021, 7:55 a.m. UTC

From: Bibby Hsieh <[e-mail]>

Although in the most platforms, the bus power of i2c
are alway on, some platforms disable the i2c bus power
in order to meet low power request.

We can control bulk regulator if it is provided in i2c
adapter device.

Signed-off-by: Bibby Hsieh <[e-mail]>
Signed-off-by: Marek Szyprowski <[e-mail]>
Signed-off-by: Hsin-Yi Wang <[e-mail]>
Reviewed-by: Matthias Brugger <[e-mail]>
---
 drivers/i2c/i2c-core-base.c | 95 +++++++++++++++++++++++++++++++++++++
 include/linux/i2c.h         |  2 +
 2 files changed, 97 insertions(+)

Comments

Wolfram Sang May 28, 2021, 7:05 p.m. UTC | #1

On Thu, May 27, 2021 at 03:55:53PM +0800, Hsin-Yi Wang wrote:
> From: Bibby Hsieh <[e-mail]>
> 
> Although in the most platforms, the bus power of i2c
> are alway on, some platforms disable the i2c bus power
> in order to meet low power request.
> 
> We can control bulk regulator if it is provided in i2c
> adapter device.
> 
> Signed-off-by: Bibby Hsieh <[e-mail]>
> Signed-off-by: Marek Szyprowski <[e-mail]>
> Signed-off-by: Hsin-Yi Wang <[e-mail]>
> Reviewed-by: Matthias Brugger <[e-mail]>

It looks good to me. I have to admit, though, that I am not a PM expert,
but I trust you guys here. Let's apply it and see what happens.

Applied to for-next, thanks!

Patch

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 5a97e4a02fa2..23bc7c269184 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -461,12 +461,14 @@  static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
 static int i2c_device_probe(struct device *dev)
 {
 	struct i2c_client	*client = i2c_verify_client(dev);
+	struct i2c_adapter	*adap;
 	struct i2c_driver	*driver;
 	int status;
 
 	if (!client)
 		return 0;
 
+	adap = client->adapter;
 	client->irq = client->init_irq;
 
 	if (!client->irq) {
@@ -532,6 +534,14 @@  static int i2c_device_probe(struct device *dev)
 
 	dev_dbg(dev, "probe\n");
 
+	if (adap->bus_regulator) {
+		status = regulator_enable(adap->bus_regulator);
+		if (status < 0) {
+			dev_err(&adap->dev, "Failed to enable bus regulator\n");
+			goto err_clear_wakeup_irq;
+		}
+	}
+
 	status = of_clk_set_defaults(dev->of_node, false);
 	if (status < 0)
 		goto err_clear_wakeup_irq;
@@ -589,8 +599,10 @@  static int i2c_device_probe(struct device *dev)
 static int i2c_device_remove(struct device *dev)
 {
 	struct i2c_client	*client = to_i2c_client(dev);
+	struct i2c_adapter      *adap;
 	struct i2c_driver	*driver;
 
+	adap = client->adapter;
 	driver = to_i2c_driver(dev->driver);
 	if (driver->remove) {
 		int status;
@@ -605,6 +617,8 @@  static int i2c_device_remove(struct device *dev)
 	devres_release_group(&client->dev, client->devres_group_id);
 
 	dev_pm_domain_detach(&client->dev, true);
+	if (!pm_runtime_status_suspended(&client->dev) && adap->bus_regulator)
+		regulator_disable(adap->bus_regulator);
 
 	dev_pm_clear_wake_irq(&client->dev);
 	device_init_wakeup(&client->dev, false);
@@ -617,6 +631,86 @@  static int i2c_device_remove(struct device *dev)
 	return 0;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int i2c_resume_early(struct device *dev)
+{
+	struct i2c_client *client = i2c_verify_client(dev);
+	int err;
+
+	if (!client)
+		return 0;
+
+	if (pm_runtime_status_suspended(&client->dev) &&
+		client->adapter->bus_regulator) {
+		err = regulator_enable(client->adapter->bus_regulator);
+		if (err)
+			return err;
+	}
+
+	return pm_generic_resume_early(&client->dev);
+}
+
+static int i2c_suspend_late(struct device *dev)
+{
+	struct i2c_client *client = i2c_verify_client(dev);
+	int err;
+
+	if (!client)
+		return 0;
+
+	err = pm_generic_suspend_late(&client->dev);
+	if (err)
+		return err;
+
+	if (!pm_runtime_status_suspended(&client->dev) &&
+		client->adapter->bus_regulator)
+		return regulator_disable(client->adapter->bus_regulator);
+
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_PM
+static int i2c_runtime_resume(struct device *dev)
+{
+	struct i2c_client *client = i2c_verify_client(dev);
+	int err;
+
+	if (!client)
+		return 0;
+
+	if (client->adapter->bus_regulator) {
+		err = regulator_enable(client->adapter->bus_regulator);
+		if (err)
+			return err;
+	}
+
+	return pm_generic_runtime_resume(&client->dev);
+}
+
+static int i2c_runtime_suspend(struct device *dev)
+{
+	struct i2c_client *client = i2c_verify_client(dev);
+	int err;
+
+	if (!client)
+		return 0;
+
+	err = pm_generic_runtime_suspend(&client->dev);
+	if (err)
+		return err;
+
+	if (client->adapter->bus_regulator)
+		return regulator_disable(client->adapter->bus_regulator);
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops i2c_device_pm = {
+	SET_LATE_SYSTEM_SLEEP_PM_OPS(i2c_suspend_late, i2c_resume_early)
+	SET_RUNTIME_PM_OPS(i2c_runtime_suspend, i2c_runtime_resume, NULL)
+};
+
 static void i2c_device_shutdown(struct device *dev)
 {
 	struct i2c_client *client = i2c_verify_client(dev);
@@ -674,6 +768,7 @@  struct bus_type i2c_bus_type = {
 	.probe		= i2c_device_probe,
 	.remove		= i2c_device_remove,
 	.shutdown	= i2c_device_shutdown,
+	.pm		= &i2c_device_pm,
 };
 EXPORT_SYMBOL_GPL(i2c_bus_type);
 
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index e8f2ac8c9c3d..953a4eecb88f 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -15,6 +15,7 @@ 
 #include <linux/device.h>	/* for struct device */
 #include <linux/sched.h>	/* for completion */
 #include <linux/mutex.h>
+#include <linux/regulator/consumer.h>
 #include <linux/rtmutex.h>
 #include <linux/irqdomain.h>		/* for Host Notify IRQ */
 #include <linux/of.h>		/* for struct device_node */
@@ -729,6 +730,7 @@  struct i2c_adapter {
 	const struct i2c_adapter_quirks *quirks;
 
 	struct irq_domain *host_notify_domain;
+	struct regulator *bus_regulator;
 };
 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)