Re: [PATCH v2 1/4] power: supply: max17040: Add IRQ handler for low SOC alert

[Matheus Castello]

Em 4/15/19 4:10 AM, Krzysztof Kozlowski escreveu:
> On Mon, 15 Apr 2019 at 03:49, Matheus Castello <matheus@xxxxxxxxxxxxxxx> wrote:
> > According datasheet max17040 has a pin for alert host for low SOC.
> > This pin can be used as external interrupt, so we need to check for
> > interrupts assigned for device and handle it.
> >
> > In hadler we are checking and storing fuel gauge registers values
> > and send an uevent to notificate user space, so user space can decide
> > save work or turn off since the alert demonstrate that the battery may
> > no have the power to keep the system turned on for much longer.
> >
> > Signed-off-by: Matheus Castello <matheus@xxxxxxxxxxxxxxx>
> > ---
> >   drivers/power/supply/max17040_battery.c | 69 +++++++++++++++++++++++--
> >   1 file changed, 64 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/power/supply/max17040_battery.c b/drivers/power/supply/max17040_battery.c
> > index 91cafc7bed30..8d2f8ed3f44c 100644
> > --- a/drivers/power/supply/max17040_battery.c
> > +++ b/drivers/power/supply/max17040_battery.c
> > @@ -13,6 +13,7 @@
> >   #include <linux/err.h>
> >   #include <linux/i2c.h>
> >   #include <linux/delay.h>
> > +#include <linux/interrupt.h>
> >   #include <linux/power_supply.h>
> >   #include <linux/max17040_battery.h>
> >   #include <linux/slab.h>
> > @@ -160,21 +161,40 @@ static void max17040_get_status(struct i2c_client *client)
> >                  chip->status = POWER_SUPPLY_STATUS_FULL;
> >   }
> >
> > +static void max17040_check_changes(struct i2c_client *client)
> > +{
> > +       max17040_get_vcell(client);
> > +       max17040_get_soc(client);
> > +       max17040_get_online(client);
> > +       max17040_get_status(client);
> > +}
> > +
> >   static void max17040_work(struct work_struct *work)
> >   {
> >          struct max17040_chip *chip;
> >
> >          chip = container_of(work, struct max17040_chip, work.work);
> > -
> > -       max17040_get_vcell(chip->client);
> > -       max17040_get_soc(chip->client);
> > -       max17040_get_online(chip->client);
> > -       max17040_get_status(chip->client);
> > +       max17040_check_changes(chip->client);
> >
> >          queue_delayed_work(system_power_efficient_wq, &chip->work,
> >                             MAX17040_DELAY);
> >   }
> >
> > +static irqreturn_t max17040_thread_handler(int id, void *dev)
> > +{
> > +       struct max17040_chip *chip = dev;
> > +       struct i2c_client *client = chip->client;
> > +
> > +       dev_warn(&client->dev, "IRQ: Alert battery low level");
> > +       /* read registers */
> > +       max17040_check_changes(chip->client);
> > +
> > +       /* send uevent */
> > +       power_supply_changed(chip->battery);
> > +
> > +       return IRQ_HANDLED;
> > +}
> > +
> >   static enum power_supply_property max17040_battery_props[] = {
> >          POWER_SUPPLY_PROP_STATUS,
> >          POWER_SUPPLY_PROP_ONLINE,
> > @@ -217,6 +237,27 @@ static int max17040_probe(struct i2c_client *client,
> >                  return PTR_ERR(chip->battery);
> >          }
> >
> > +       /* check interrupt */
> > +       if (client->irq) {
> > +               int ret;
> > +               unsigned int flags;
> > +
> > +               dev_info(&client->dev, "IRQ: enabled\n");
> > +               flags = IRQF_TRIGGER_FALLING | IRQF_ONESHOT;
> > +
> > +               ret = devm_request_threaded_irq(&client->dev, client->irq, NULL,
> > +                                               max17040_thread_handler, flags,
> > +                                               chip->battery->desc->name,
> > +                                               chip);
> > +
> > +               if (ret) {
> > +                       client->irq = 0;
> > +                       if (ret != -EBUSY)
>
> Why not on EBUSY?
>
> > +                               dev_warn(&client->dev,
> > +                                       "Failed to get IRQ err %d\n", ret);
> > +               }
> > +       }
> > +
> >          max17040_reset(client);
> >          max17040_get_version(client);
> >
> > @@ -224,6 +265,8 @@ static int max17040_probe(struct i2c_client *client,
> >          queue_delayed_work(system_power_efficient_wq, &chip->work,
> >                             MAX17040_DELAY);
> >
> > +       device_init_wakeup(&client->dev, 1);
>
> Either you parse DT for wakeup-source property and use it... or you
> unconditionally enable wakeup. In the second case - there is no point
> to check later for device_may_wakeup(). Instead check the return value
> of device_init_wakeup().
>
> > +
> >          return 0;
> >   }
> >
> > @@ -244,6 +287,14 @@ static int max17040_suspend(struct device *dev)
> >          struct max17040_chip *chip = i2c_get_clientdata(client);
> >
> >          cancel_delayed_work(&chip->work);
> > +
> > +       if (client->irq) {
> > +               if (device_may_wakeup(dev))
> > +                       enable_irq_wake(client->irq);
> > +               else
> > +                       disable_irq_wake(client->irq);
>
> Did you try the wakeup from suspend? You do not have a disable_irq()
> here which usually was needed for interrupts to work properly on
> suspend. Maybe this was fixed?
>
> Best regards,
> Krzysztof
Hi Krzysztof,

I test it using mem state and suspend, resuming seems to have worked 
correctly ...

Thanks for the review, I'm working in your suggestions and I expect to 
send v3 this weekend.

Best Regards,
Matheus Castello