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

[Bibby Hsieh <bibby.hsieh@mediatek.com>]

Hi, Rafael,

I'm Sorry to bother you.

I'm not sure if you receive our email...
So I re-sent this email to your another email.

Thanks.

Bibby

On Mon, 2020-02-17 at 18:45 +0900, Tomasz Figa wrote:
> Hi Rafael,
> 
> On Tue, Jan 28, 2020 at 4:31 PM Tomasz Figa <tfiga@chromium.org> wrote:
> >
> > Hi Rafael,
> >
> > On Thu, Jan 16, 2020 at 11:56 AM Bibby Hsieh <bibby.hsieh@mediatek.com> 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>
> > > ---
> > >  drivers/i2c/i2c-core-base.c | 81 +++++++++++++++++++++++++++++++++++++
> > >  include/linux/i2c.h         |  3 ++
> > >  2 files changed, 84 insertions(+)
> > >
> >
> > I posted some comments in a separate reply [1] and Wolfram confirmed
> > that he's fine with the approach [2]. Would you have some time to take
> > a look from the PM point of view? Thanks.
> >
> > [1] https://patchwork.ozlabs.org/patch/1223991/#2350984
> > [2] https://patchwork.ozlabs.org/patch/1223991/#2351032
> >
> > Please let me know if you want me to CC you directly on any of those replies.
> 
> Would you have a few minutes to take a look at this?
> 
> Thanks,
> Tomasz
> 
> >
> > Best regards,
> > Tomasz
> >
> > > diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> > > index 9333c865d4a9..9b9e96b094ca 100644
> > > --- a/drivers/i2c/i2c-core-base.c
> > > +++ b/drivers/i2c/i2c-core-base.c
> > > @@ -306,6 +306,7 @@ 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 = client->adapter;
> > >         struct i2c_driver       *driver;
> > >         int status;
> > >
> > > @@ -371,6 +372,12 @@ static int i2c_device_probe(struct device *dev)
> > >
> > >         dev_dbg(dev, "probe\n");
> > >
> > > +       status = regulator_enable(adap->bus_reg);
> > > +       if (status != 0) {
> > > +               dev_err(&adap->dev, "Failed to enable power regulator\n");
> > > +               goto err_clear_wakeup_irq;
> > > +       }
> > > +
> > >         status = of_clk_set_defaults(dev->of_node, false);
> > >         if (status < 0)
> > >                 goto err_clear_wakeup_irq;
> > > @@ -407,6 +414,7 @@ static int i2c_device_probe(struct device *dev)
> > >  static int i2c_device_remove(struct device *dev)
> > >  {
> > >         struct i2c_client       *client = i2c_verify_client(dev);
> > > +       struct i2c_adapter      *adap = client->adapter;
> > >         struct i2c_driver       *driver;
> > >         int status = 0;
> > >
> > > @@ -420,6 +428,8 @@ static int i2c_device_remove(struct device *dev)
> > >         }
> > >
> > >         dev_pm_domain_detach(&client->dev, true);
> > > +       if (!pm_runtime_status_suspended(&adap->dev))
> > > +               regulator_disable(adap->bus_reg);
> > >
> > >         dev_pm_clear_wake_irq(&client->dev);
> > >         device_init_wakeup(&client->dev, false);
> > > @@ -431,6 +441,71 @@ static int i2c_device_remove(struct device *dev)
> > >         return status;
> > >  }
> > >
> > > +#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)
> > > +};
> > > +
> > >  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;
> > >  };
> > >  #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
> > >
> > > --
> > > 2.18.0