linux-kernel - Re: [PATCH v5] hwmon: (pmbus/core): Implement regulator get

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Date:   Thu, 24 Nov 2022 06:18:57 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Naresh Solanki <naresh.solanki@...ements.com>,
        linux-hwmon@...r.kernel.org, Jean Delvare <jdelvare@...e.com>
Cc:     Patrick Rudolph <patrick.rudolph@...ements.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5] hwmon: (pmbus/core): Implement regulator get_status

On 11/24/22 00:34, Naresh Solanki wrote:
> From: Patrick Rudolph <patrick.rudolph@...ements.com>
> 
> Add get_status for pmbus_regulator_ops.
> 
> ---
> Changes:
> - use lock throughout the function
> - Avoid line continuation upto 100 column
> - Optimize use of & and | operator
> - Check for VOUT, IOUT, TEMPERATURE bit in status word before checking
>    respective status register for fault.
> - Report regulator current status.
> - Utilize get_error_flag to check for regulator errors.
> - Check for return value of function get_error_flag
> 
> Signed-off-by: Patrick Rudolph <patrick.rudolph@...ements.com>
> Signed-off-by: Naresh Solanki <Naresh.Solanki@...ements.com>
> ---
>   drivers/hwmon/pmbus/pmbus_core.c | 44 ++++++++++++++++++++++++++++++++
>   1 file changed, 44 insertions(+)
> 
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index 20ca26e19db7..0b13214c662f 100644
> --- a/drivers/hwmon/pmbus/pmbus_core.c
> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> @@ -2855,6 +2855,49 @@ static int pmbus_regulator_get_error_flags(struct regulator_dev *rdev, unsigned
>   	return 0;
>   }
>   
> +static int pmbus_regulator_get_status(struct regulator_dev *rdev)
> +{
> +	struct device *dev = rdev_get_dev(rdev);
> +	struct i2c_client *client = to_i2c_client(dev->parent);
> +	struct pmbus_data *data = i2c_get_clientdata(client);
> +	u8 page = rdev_get_id(rdev);
> +	int status, ret;
> +
> +	mutex_lock(&data->update_lock);
> +	status = pmbus_get_status(client, page, PMBUS_STATUS_WORD);
> +	if (status < 0) {
> +		ret = status;
> +		goto unlock;
> +	}
> +
> +	if (status & PB_STATUS_OFF) {
> +		ret = REGULATOR_STATUS_OFF;
> +		goto unlock;
> +	}
> +
> +	/* If regulator is ON & reports power good then return ON */
> +	if (!(status & PB_STATUS_POWER_GOOD_N)) {
> +		ret = REGULATOR_STATUS_ON;
> +		goto unlock;
> +	}
> +
> +	if (rdev->desc->ops->get_error_flags) {

Looking into this again, why is this check necessary ? Isn't this
the regulator_ops from below ? Also, why not just call
pmbus_regulator_get_error_flags() directly ?

> +		ret = rdev->desc->ops->get_error_flags(rdev, &status);
> +		if (ret)
> +			goto unlock;
> +
> +		if (status & (REGULATOR_ERROR_UNDER_VOLTAGE | REGULATOR_ERROR_OVER_CURRENT |
> +		   REGULATOR_ERROR_REGULATION_OUT | REGULATOR_ERROR_FAIL |
> +		   REGULATOR_ERROR_OVER_TEMP))
> +			ret = REGULATOR_STATUS_ERROR;

If the condition above is false, the return value will be 0, or
REGULATOR_STATUS_OFF. Is that intentional ?

> +	} else
> +		ret = REGULATOR_STATUS_UNDEFINED;
> +

CHECK: braces {} should be used on all arms of this statement
#72: FILE: drivers/hwmon/pmbus/pmbus_core.c:2884:
+	if (rdev->desc->ops->get_error_flags) {
[...]
+	} else

Guenter

> +unlock:
> +	mutex_unlock(&data->update_lock);
> +	return ret;
> +}
> +
>   static int pmbus_regulator_get_low_margin(struct i2c_client *client, int page)
>   {
>   	struct pmbus_data *data = i2c_get_clientdata(client);
> @@ -2995,6 +3038,7 @@ const struct regulator_ops pmbus_regulator_ops = {
>   	.disable = pmbus_regulator_disable,
>   	.is_enabled = pmbus_regulator_is_enabled,
>   	.get_error_flags = pmbus_regulator_get_error_flags,
> +	.get_status = pmbus_regulator_get_status,
>   	.get_voltage = pmbus_regulator_get_voltage,
>   	.set_voltage = pmbus_regulator_set_voltage,
>   	.list_voltage = pmbus_regulator_list_voltage,
> 
> base-commit: 2c71b3246ec3246522e8cb7c8191dc7a5d62cc70