linux-kernel - Re: [PATCH v5 2/5] hwmon: (pmbus/core): Add interrupt support

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Message-ID: <20221201201333.GB2110128@roeck-us.net>
Date:   Thu, 1 Dec 2022 12:13:33 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Naresh Solanki <naresh.solanki@...ements.com>
Cc:     devicetree@...r.kernel.org, Jean Delvare <jdelvare@...e.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>, linux-kernel@...r.kernel.org,
        linux-hwmon@...r.kernel.org,
        Patrick Rudolph <patrick.rudolph@...ements.com>
Subject: Re: [PATCH v5 2/5] hwmon: (pmbus/core): Add interrupt support

On Thu, Dec 01, 2022 at 08:30:21PM +0100, Naresh Solanki wrote:
> From: Patrick Rudolph <patrick.rudolph@...ements.com>
> 
> Implement PMBUS irq handler.
> 
> Signed-off-by: Patrick Rudolph <patrick.rudolph@...ements.com>
> Signed-off-by: Naresh Solanki <Naresh.Solanki@...ements.com>
> ---
>  drivers/hwmon/pmbus/pmbus.h      |  2 +-
>  drivers/hwmon/pmbus/pmbus_core.c | 89 ++++++++++++++++++++++++++++++++
>  2 files changed, 90 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
> index 10fb17879f8e..6b2e6cf93b19 100644
> --- a/drivers/hwmon/pmbus/pmbus.h
> +++ b/drivers/hwmon/pmbus/pmbus.h
> @@ -26,7 +26,7 @@ enum pmbus_regs {
>  
>  	PMBUS_CAPABILITY		= 0x19,
>  	PMBUS_QUERY			= 0x1A,
> -
> +	PMBUS_SMBALERT_MASK		= 0x1B,
>  	PMBUS_VOUT_MODE			= 0x20,
>  	PMBUS_VOUT_COMMAND		= 0x21,
>  	PMBUS_VOUT_TRIM			= 0x22,
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index a95f998ca247..6a3a3fd59b8e 100644
> --- a/drivers/hwmon/pmbus/pmbus_core.c
> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> @@ -3077,11 +3077,94 @@ static int pmbus_regulator_register(struct pmbus_data *data)
>  
>  	return 0;
>  }
> +
> +static int pmbus_write_smbalert_mask(struct i2c_client *client, u8 page, u8 reg, u8 val)
> +{
> +	return pmbus_write_word_data(client, page, PMBUS_SMBALERT_MASK, reg | (val << 8));
> +}
> +
> +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;
> +	u8 page;
> +
> +	for (i = 0; i < data->info->num_regulators; i++) {

This doesn't take into account situations where there is no regulator.
Remember, regulator support is optional. The entire code still completely
depends on regulator support.

> +
> +		if (!data->rdevs[i])
> +			continue;
> +
> +		page = rdev_get_id(data->rdevs[i]);
> +		mutex_lock(&data->update_lock);
> +		status = pmbus_read_status_word(client, page);
> +		if (status < 0) {
> +			mutex_unlock(&data->update_lock);
> +			return status;
> +		}
> +
> +		if (status & ~(PB_STATUS_OFF | PB_STATUS_BUSY | PB_STATUS_POWER_GOOD_N))
> +			pmbus_clear_fault_page(client, page);
> +
> +		mutex_unlock(&data->update_lock);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int pmbus_irq_setup(struct i2c_client *client, struct pmbus_data *data)
> +{
> +	struct device *dev = &client->dev;
> +	const struct pmbus_regulator_status_category *cat;
> +	const struct pmbus_regulator_status_assoc *bit;
> +	int i, j, err, ret, func;
> +	u8 mask;
> +
> +	for (i = 0; i < data->info->pages; i++) {
> +		func = data->info->func[i];
> +
> +		for (j = 0; j < ARRAY_SIZE(pmbus_regulator_flag_map); j++) {
> +			cat = &pmbus_regulator_flag_map[j];
> +			if (!(func & cat->func))
> +				continue;
> +			mask = 0;
> +			for (bit = cat->bits; bit->pflag; bit++)
> +				mask |= bit->pflag;
> +
> +			err = pmbus_write_smbalert_mask(client, i, cat->reg, ~mask);
> +			if (err)
> +				dev_err(dev, "Failed to set smbalert for reg 0x%02x\n",	cat->reg);
> +		}
> +
> +		pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_CML, 0xff);
> +		pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_OTHER, 0xff);
> +		pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_MFR_SPECIFIC, 0xff);
> +		if (data->info->func[i] & PMBUS_HAVE_FAN12)
> +			pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_FAN_12, 0xff);
> +		if (data->info->func[i] & PMBUS_HAVE_FAN34)
> +			pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_FAN_34, 0xff);
> +	}
> +
> +	/* Register notifiers - can fail if IRQ is not given */
> +	ret = devm_request_threaded_irq(dev, client->irq, NULL, pmbus_fault_handler,
> +			      0, "pmbus-irq", data);
> +	if (ret) {
> +		dev_warn(dev, "IRQ disabled %d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
>  #else
>  static int pmbus_regulator_register(struct pmbus_data *data)
>  {
>  	return 0;
>  }
> +static int pmbus_irq_setup(struct i2c_client *client, struct pmbus_data *data)
> +{
> +	return 0;
> +}

I understand that you really only care about regulator support,
but this is still unacceptable. Interrupt support is independent of
regulator support and needs to be handled as such.

Guenter

>  #endif
>  
>  static struct dentry *pmbus_debugfs_dir;	/* pmbus debugfs directory */
> @@ -3446,6 +3529,12 @@ int pmbus_do_probe(struct i2c_client *client, struct pmbus_driver_info *info)
>  	if (ret)
>  		return ret;
>  
> +	if (client->irq > 0) {
> +		ret = pmbus_irq_setup(client, data);
> +		if (ret)
> +			return ret;
> +	}
> +
>  	ret = pmbus_init_debugfs(client, data);
>  	if (ret)
>  		dev_warn(dev, "Failed to register debugfs\n");
> -- 
> 2.37.3
>