linux-kernel - Re: [PATCH] hwmon: pm_bus: core: Implement regulator get

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Message-ID: <20221117223856.GA675221@roeck-us.net>
Date:   Thu, 17 Nov 2022 14:38:56 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Naresh Solanki <naresh.solanki@...ements.com>
Cc:     linux-hwmon@...r.kernel.org, Jean Delvare <jdelvare@...e.com>,
        Patrick Rudolph <patrick.rudolph@...ements.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] hwmon: pm_bus: core: Implement regulator get_status

On Thu, Nov 17, 2022 at 08:43:51PM +0100, Naresh Solanki wrote:
> From: Patrick Rudolph <patrick.rudolph@...ements.com>
> 
> Add get_status for pmbus_regulator_ops.
> 
> Signed-off-by: Patrick Rudolph <patrick.rudolph@...ements.com>
> Signed-off-by: Naresh Solanki <Naresh.Solanki@...ements.com>
> ---
>  drivers/hwmon/pmbus/pmbus_core.c | 78 ++++++++++++++++++++++++++++++++
>  1 file changed, 78 insertions(+)
> 
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index 7ec04934747e..d5e2b0662da5 100644
> --- a/drivers/hwmon/pmbus/pmbus_core.c
> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> @@ -2851,6 +2851,83 @@ 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, status2;
> +
> +	mutex_lock(&data->update_lock);
> +	status = pmbus_get_status(client, page, PMBUS_STATUS_WORD);
> +	mutex_unlock(&data->update_lock);
> +	if (status < 0)
> +		 return status;
> +
> +	if (status & PB_STATUS_VIN_UV ||
> +	    status & PB_STATUS_IOUT_OC ||
> +	    status & PB_STATUS_VOUT_OV ||
> +	    status & PB_STATUS_UNKNOWN)
> +		 return REGULATOR_STATUS_ERROR;

	if (status & (PB_STATUS_VIN_UV | PB_STATUS_IOUT_OC | ...))

PB_STATUS_UNKNOWN can mean anything and doesn't necessarily indicate
an error. Not sure if it makes sense to report that as error.

> +
> +	if (status & PB_STATUS_VOUT_OV &&

PB_STATUS_VOUT_OV was checked above already, and the code won't get here
if the bit is set.

> +	    data->info->func[page] & PMBUS_HAVE_STATUS_VOUT) {
> +		 mutex_lock(&data->update_lock);
> +		 status2 = _pmbus_read_byte_data(client, page, PMBUS_STATUS_VOUT);
> +		 mutex_unlock(&data->update_lock);
> +		 if (status2 < 0)
> +			  return status2;
> +		 if (status2 & PB_VOLTAGE_OV_FAULT ||
> +		     status2 & PB_VOLTAGE_UV_FAULT)

		if (status2 & (...))

> +			  return REGULATOR_STATUS_ERROR;
> +	}
> +	if (status & PB_STATUS_IOUT_OC &&

Same as above - this condition will never be true.

> +	    data->info->func[page] & PMBUS_HAVE_STATUS_IOUT) {
> +		 mutex_lock(&data->update_lock);
> +		 status2 = _pmbus_read_byte_data(client, page, PMBUS_STATUS_IOUT);
> +		 mutex_unlock(&data->update_lock);
> +		 if (status2 < 0)
> +			  return status2;
> +		 if (status2 & PB_POUT_OP_FAULT ||
> +		     status2 & PB_IOUT_UC_FAULT ||
> +		     status2 & PB_IOUT_OC_LV_FAULT ||
> +		     status2 & PB_IOUT_OC_FAULT)

		if (status2 & (...))

> +			  return REGULATOR_STATUS_ERROR;
> +	}
> +	if (status & PB_STATUS_VIN_UV &&

and again.

> +	    data->info->func[page] & PMBUS_HAVE_STATUS_INPUT) {
> +		 mutex_lock(&data->update_lock);
> +		 status2 = _pmbus_read_byte_data(client, page, PMBUS_STATUS_INPUT);
> +		 mutex_unlock(&data->update_lock);
> +		 if (status2 < 0)
> +			  return status2;
> +		 if (status2 & PB_IIN_OC_FAULT ||
> +		     status2 & PB_VOLTAGE_OV_FAULT ||
> +		     status2 & PB_VOLTAGE_UV_FAULT)

and again

> +			  return REGULATOR_STATUS_ERROR;
> +	}
> +	if (status & PB_STATUS_TEMPERATURE &&
> +	    data->info->func[page] & PMBUS_HAVE_STATUS_TEMP) {
> +		 mutex_lock(&data->update_lock);
> +		 status2 = _pmbus_read_byte_data(client, page, PMBUS_STATUS_TEMPERATURE);
> +		 mutex_unlock(&data->update_lock);
> +		 if (status2 < 0)
> +			  return status2;
> +		 if (status2 & PB_TEMP_UT_FAULT ||
> +		     status2 & PB_TEMP_OT_FAULT)

and again

> +			  return REGULATOR_STATUS_ERROR;
> +	}
> +
> +	if (status & PB_STATUS_OFF)
> +		 return REGULATOR_STATUS_OFF;
> +
> +	if (status & PB_STATUS_POWER_GOOD_N)
> +		 return REGULATOR_STATUS_OFF;

Wouldn't it be better to check those bits first ?
Also, it should be

	if (status & (PB_STATUS_OFF | PB_STATUS_POWER_GOOD_N))

> +
> +	return REGULATOR_STATUS_ON;
> +}
> +
>  static int pmbus_regulator_get_low_margin(struct i2c_client *client, int page)
>  {
>  	struct pmbus_data *data = i2c_get_clientdata(client);
> @@ -2991,6 +3068,7 @@ 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: 27fea302952d8c90cafbdbee96bafeca03544401
> -- 
> 2.37.3
>