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Message-ID: <f432eb79-6efb-2b69-2f20-ae06999d60de@9elements.com>
Date: Tue, 14 Feb 2023 19:40:19 +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 3/4] hwmon: (pmbus/core): Add interrupt support
Hi
On 11-02-2023 09:07 pm, Guenter Roeck wrote:
> On Tue, Feb 07, 2023 at 01:02:40PM +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 | 85 ++++++++++++++++++++++++++++++++
>> 2 files changed, 86 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
>> index 713ea7915425..11e84e141126 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 5ccae8126a56..d5403baad60a 100644
>> --- a/drivers/hwmon/pmbus/pmbus_core.c
>> +++ b/drivers/hwmon/pmbus/pmbus_core.c
>> @@ -3093,6 +3093,85 @@ static int pmbus_regulator_register(struct pmbus_data *data)
>> }
>> #endif
>>
>> +static int pmbus_write_smbalert_mask(struct i2c_client *client, u8 page, u8 reg, u8 val)
>> +{
>> + int err;
>> +
>> + err = pmbus_check_word_register(client, page, reg | (val << 8));
>> + if (err)
>> + return err;
>
> I am not convinced that this is necessary. The next command will return an
> error anyway if the register or the specific mask is not supported, so what
> is the point ?
>
Sure. will remove.
>> +
>> + 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;
>> +
>> + mutex_lock(&data->update_lock);
>> + for (i = 0; i < data->info->pages; i++) {
>> + status = pmbus_read_status_word(client, i);
>> + 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, i);
>> + }
>> + 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_status_category *cat;
>> + const struct pmbus_status_assoc *bit;
>> + int i, j, err, ret, func;
>> + u8 mask;
>> + u8 misc_status[] = {PMBUS_STATUS_CML, PMBUS_STATUS_OTHER, PMBUS_STATUS_MFR_SPECIFIC,
>> + PMBUS_STATUS_FAN_12, PMBUS_STATUS_FAN_34};
>
> static const u8 ...
>
Done
>> +
>> + for (i = 0; i < data->info->pages; i++) {
>> + func = data->info->func[i];
>> +
>> + for (j = 0; j < ARRAY_SIZE(pmbus_status_flag_map); j++) {
>> + cat = &pmbus_status_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_once(dev, "Failed to set smbalert for reg 0x%02x\n",
>> + cat->reg);
>
> dev_err implies an error. This is ignored and thus not an error. On top of that,
> not all chips support PMBUS_SMBALERT_MASK. All of those would see this message.
> We can't have that. At best make it a dev_dbg.
>
Sure. Will make it dev_dbg_once.
>> + }
>> +
>> + for (j = 0; j < ARRAY_SIZE(misc_status); j++) {
>> + err = pmbus_write_smbalert_mask(client, i, misc_status[j], 0xff);
>> + if (err)
>> + dev_err_once(dev, "Failed to set smbalert for reg 0x%02x\n",
>> + misc_status[j]);
>
> We definitely can't have a message here; that would fire for almost
> every chip.
>
Sure. Will remove printing of error here.
>> + }
>> + }
>> +
>> + /* Register notifiers - can fail if IRQ is not given */
>
> If there is no irq, what is the point of executing this code in the first
> place ? No, wait, in that case the function isn't called in the first place.
> I think the comment doesn't add any value and is just confusing.
>
Will clean this comment.
>> + ret = devm_request_threaded_irq(dev, client->irq, NULL, pmbus_fault_handler, 0,
>> + "pmbus-irq", data);
>> + if (ret) {
>
> Why both "err" and "ret" ?
>
Will replace ret with err.
>> + dev_warn(dev, "IRQ disabled %d\n", ret);
>
> The calling code aborts, so this should be dev_err() and say something
> better than "IRQ disabled"; It should be something like "failed to
> request irq".
>
Sure. Will update to "failed to request an irq"
>> + return ret;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> static struct dentry *pmbus_debugfs_dir; /* pmbus debugfs directory */
>>
>> #if IS_ENABLED(CONFIG_DEBUG_FS)
>> @@ -3455,6 +3534,12 @@ 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;
>> + }
>> +
>
> I think it would be better to have the check in pmbus_irq_setup():
>
> pmbus_irq_setup()
> {
> if (!client->irq)
> return 0;
>
> ...
> }
>
> and here
> ret = pmbus_irq_setup(client, data);
> if (ret)
> return ret;
>
>
Sure
>> ret = pmbus_init_debugfs(client, data);
>> if (ret)
>> dev_warn(dev, "Failed to register debugfs\n");
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