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

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Message-ID: <20230211154647.GA204954@roeck-us.net>
Date:   Sat, 11 Feb 2023 07:46:47 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Naresh Solanki <naresh.solanki@...ements.com>
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

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.

>  		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).

>  
>  	return IRQ_HANDLED;
>  }