Re: [PATCH v21 1/5] i2c: core: support bus regulator controlling in adapter

[Matthias Brugger <matthias.bgg@gmail.com>]

On 07/05/2021 15:14, Hsin-Yi Wang wrote:
> From: Bibby Hsieh <bibby.hsieh@mediatek.com>
> 
> 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 <bibby.hsieh@mediatek.com>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>

Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>

> ---
>  drivers/i2c/i2c-core-base.c | 95 +++++++++++++++++++++++++++++++++++++
>  include/linux/i2c.h         |  2 +
>  2 files changed, 97 insertions(+)
> 
> 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)
>  
>