Re: [PATCH v10 4/4] i2c: core: support bus regulator controlling in adapter

[Tomasz Figa <tfiga@chromium.org>]

On Tue, Jan 28, 2020 at 3:36 PM Wolfram Sang <wsa@the-dreams.de> wrote:
>
> On Thu, Jan 16, 2020 at 10:56:37AM +0800, Bibby Hsieh wrote:
> > 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 get and enable bulk regulator in i2c adapter device.
> >
> > Signed-off-by: Bibby Hsieh <bibby.hsieh@mediatek.com>
>
> ...
>
> > +#ifdef CONFIG_PM_SLEEP
> > +static int i2c_resume(struct device *dev)
> > +{
> > +     struct i2c_client *client = i2c_verify_client(dev);
> > +     struct i2c_adapter *adap = client->adapter;
> > +     int err;
> > +
> > +     if (pm_runtime_status_suspended(&adap->dev)) {
> > +             err = regulator_enable(adap->bus_reg);
> > +             if (err)
> > +                     return err;
> > +     }
> > +
> > +     return pm_generic_resume(dev);
> > +}
> > +
> > +static int i2c_suspend(struct device *dev)
> > +{
> > +     struct i2c_client *client = i2c_verify_client(dev);
> > +     struct i2c_adapter *adap = client->adapter;
> > +     int err;
> > +
> > +     if (!pm_runtime_status_suspended(&adap->dev)) {
> > +             err = regulator_disable(adap->bus_reg);
> > +             if (err)
> > +                     return err;
> > +     }
> > +
> > +     return pm_generic_suspend(dev);
> > +}
> > +#endif
> > +
> > +#ifdef CONFIG_PM
> > +static int i2c_runtime_resume(struct device *dev)
> > +{
> > +     struct i2c_client *client = i2c_verify_client(dev);
> > +     struct i2c_adapter *adap = client->adapter;
> > +     int err;
> > +
> > +     err = regulator_enable(adap->bus_reg);
> > +     if (err)
> > +             return err;
> > +
> > +     return pm_generic_runtime_resume(dev);
> > +}
> > +
> > +static int i2c_runtime_suspend(struct device *dev)
> > +{
> > +     struct i2c_client *client = i2c_verify_client(dev);
> > +     struct i2c_adapter *adap = client->adapter;
> > +     int err;
> > +
> > +     err = pm_generic_runtime_suspend(dev);
> > +     if (err)
> > +             return err;
> > +
> > +     return regulator_disable(adap->bus_reg);
> > +}
> > +#endif
> > +
> > +static const struct dev_pm_ops i2c_device_pm = {
> > +     SET_SYSTEM_SLEEP_PM_OPS(i2c_suspend, i2c_resume)
> > +     SET_RUNTIME_PM_OPS(i2c_runtime_suspend, i2c_runtime_resume, NULL)
> > +};
> > +
>
> It looks good to me, yet I am not a PM expert. An ack from someone more
> into that topic would be great, if possible.
>
> >  static void i2c_device_shutdown(struct device *dev)
> >  {
> >       struct i2c_client *client = i2c_verify_client(dev);
> > @@ -488,6 +563,7 @@ 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);
> >
> > @@ -1351,6 +1427,11 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
> >               goto out_reg;
> >
> >       dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
> > +     adap->bus_reg = devm_regulator_get(&adap->dev, "bus");
> > +     if (IS_ERR(adap->bus_reg)) {
> > +             res = PTR_ERR(adap->bus_reg);
> > +             goto out_reg;
> > +     }
> >
> >       pm_runtime_no_callbacks(&adap->dev);
> >       pm_suspend_ignore_children(&adap->dev, true);
> > diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> > index d2f786706657..833b81a680da 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 */
> > @@ -330,6 +331,7 @@ struct i2c_client {
> >       int init_irq;                   /* irq set at initialization    */
> >       int irq;                        /* irq issued by device         */
> >       struct list_head detected;
> > +
> >  #if IS_ENABLED(CONFIG_I2C_SLAVE)
> >       i2c_slave_cb_t slave_cb;        /* callback for slave mode      */
> >  #endif
> > @@ -723,6 +725,7 @@ struct i2c_adapter {
> >       const struct i2c_adapter_quirks *quirks;
> >
> >       struct irq_domain *host_notify_domain;
> > +     struct regulator *bus_reg;
>
> "bus_regulator" please. "reg" is ambigious with "register".
>
> And what Tomasz said, of course.
>

Thanks a lot.

I've added Rafael and linux-pm in another reply quoting the whole patch.

Best regards,
Tomasz