linux-kernel - Re: [PATCH v2 4/4] hwmon: (pmbus/core): Notify hwmon events

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Message-ID: <2b8df4a4-23d0-8749-4e09-59734042e7a9@9elements.com>
Date:   Tue, 14 Feb 2023 20:52:54 +0530
From:   Naresh Solanki <naresh.solanki@...ements.com>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     Jean Delvare <jdelvare@...e.com>, linux-hwmon@...r.kernel.org,
        Patrick Rudolph <patrick.rudolph@...ements.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 4/4] hwmon: (pmbus/core): Notify hwmon events

Hi

On 14-02-2023 08:24 pm, Guenter Roeck wrote:
> On 2/14/23 06:11, Naresh Solanki wrote:
>> Hi,
>>
>> On 11-02-2023 09:16 pm, Guenter Roeck wrote:
>>> On Tue, Feb 07, 2023 at 01:02:41PM +0100, Naresh Solanki wrote:
>>>> From: Patrick Rudolph <patrick.rudolph@...ements.com>
>>>>
>>>> Notify hwmon events using the pmbus irq handler.
>>>>
>>>> Signed-off-by: Patrick Rudolph <patrick.rudolph@...ements.com>
>>>> Signed-off-by: Naresh Solanki <Naresh.Solanki@...ements.com>
>>>> ...
>>>> Changes in V2
>>>> - Remove __maybe_unsed attribute as its not needed.
>>>> ---
>>>>   drivers/hwmon/pmbus/pmbus_core.c | 48 
>>>> ++++++++++++++++++++++++++++----
>>>>   1 file changed, 43 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/drivers/hwmon/pmbus/pmbus_core.c 
>>>> b/drivers/hwmon/pmbus/pmbus_core.c
>>>> index d5403baad60a..f6778a9c7126 100644
>>>> --- a/drivers/hwmon/pmbus/pmbus_core.c
>>>> +++ b/drivers/hwmon/pmbus/pmbus_core.c
>>>> @@ -2735,8 +2735,36 @@ static const struct pmbus_status_category 
>>>> __maybe_unused pmbus_status_flag_map[]
>>>>       },
>>>>   };
>>>> +#define to_dev_attr(_dev_attr) \
>>>> +    container_of(_dev_attr, struct device_attribute, attr)
>>>> +
>>>> +static void pmbus_notify(struct pmbus_data *data, int page, int 
>>>> reg, int flags)
>>>> +{
>>>> +    int i;
>>>> +
>>>> +    for (i = 0; i < data->num_attributes; i++) {
>>>> +        struct device_attribute *da = 
>>>> to_dev_attr(data->group.attrs[i]);
>>>> +        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
>>>> +        int index = attr->index;
>>>> +        u16 smask = pb_index_to_mask(index);
>>>> +        u8 spage = pb_index_to_page(index);
>>>> +        u16 sreg = pb_index_to_reg(index);
>>>> +
>>>> +        if (reg == sreg && page == spage && (smask & flags)) {
>>>> +            dev_dbg(data->dev, "sysfs notify: %s", da->attr.name);
>>>> +            sysfs_notify(&data->dev->kobj, NULL, da->attr.name);
>>>> +            kobject_uevent(&data->dev->kobj, KOBJ_CHANGE);
>>>> +            flags &= ~smask;
>>>> +        }
>>>> +
>>>> +        if (!flags)
>>>> +            break;
>>>> +    }
>>>> +}
>>>> +
>>>> +static int pmbus_get_flags(struct pmbus_data *data, u8 page, 
>>>> unsigned int *flags,
>>>> +               bool notify)
>>>> -static int __maybe_unused pmbus_get_flags(struct pmbus_data *data, 
>>>> u8 page, unsigned int *flags)
>>>>   {
>>>>       int i, status, ret;
>>>>       const struct pmbus_status_category *cat;
>>>> @@ -2764,6 +2792,10 @@ static int __maybe_unused 
>>>> pmbus_get_flags(struct pmbus_data *data, u8 page, unsi
>>>>               if (status & bit->pflag)
>>>>                   *flags |= bit->rflag;
>>>>           }
>>>> +
>>>> +        if (notify && status)
>>>> +            pmbus_notify(data, page, cat->reg, status);
>>>> +
>>>>       }
>>>>       /*
>>>> @@ -2866,7 +2898,7 @@ static int 
>>>> pmbus_regulator_get_error_flags(struct regulator_dev *rdev, unsigned
>>>>       struct i2c_client *client = to_i2c_client(dev->parent);
>>>>       struct pmbus_data *data = i2c_get_clientdata(client);
>>>> -    return pmbus_get_flags(data, rdev_get_id(rdev), flags);
>>>> +    return pmbus_get_flags(data, rdev_get_id(rdev), flags, false);
>>>>   }
>>>>   static int pmbus_regulator_get_status(struct regulator_dev *rdev)
>>>> @@ -3108,10 +3140,14 @@ static irqreturn_t pmbus_fault_handler(int 
>>>> irq, void *pdata)
>>>>   {
>>>>       struct pmbus_data *data = pdata;
>>>>       struct i2c_client *client = to_i2c_client(data->dev);
>>>> -    int i, status;
>>>> +    int i, status, ret;
>>>> -    mutex_lock(&data->update_lock);
>>>>       for (i = 0; i < data->info->pages; i++) {
>>>> +        ret = pmbus_get_flags(data, i, &status, true);
>>>> +        if (ret)
>>>> +            return ret;
>>>> +
>>>> +        mutex_lock(&data->update_lock);
>>>
>>> You should introduce a locked version of pmbus_get_flags() and call
>>> that function, and keep the existing locking in place.
>>>
>> I'm not sure if you meant to have pmbus_get_flags that wont use lock?
>>
> 
> 
> __pmbus_get_flags(...)
> {
>      /* no lock acquired here */
> }
> 
> pmbus_get_flags(...)
> {
>      int ret;
> 
>      mutex_lock(&data->update_lock);
>      ret = __pmbus_get_flags(...);
>      mutex_unlock(&data->update_lock);
>      return ret;
> }
> 
> Then call __pmbus_get_flags() from above code.
Sure. Will add that change.
> 
> Guenter
> 
>>>>           status = pmbus_read_status_word(client, i);
>>>>           if (status < 0) {
>>>>               mutex_unlock(&data->update_lock);
>>>> @@ -3120,8 +3156,10 @@ static irqreturn_t pmbus_fault_handler(int 
>>>> irq, void *pdata)
>>>>           if (status & ~(PB_STATUS_OFF | PB_STATUS_BUSY | 
>>>> PB_STATUS_POWER_GOOD_N))
>>>>               pmbus_clear_fault_page(client, i);
>>>> +
>>>> +        mutex_unlock(&data->update_lock);
>>>>       }
>>>> -    mutex_unlock(&data->update_lock);
>>>> +
>>>
>>> This would add a second empty line (not that it matters because the code
>>> should not change the locking in the first place).
>>>
>> Will remove the new line
>>>>       return IRQ_HANDLED;
>>>>   }
>