Re: [PATCH RESEND v6 1/5] hwmon: (pmbus/core): Add interrupt support
From: Naresh Solanki
Date: Tue Jan 03 2023 - 10:27:13 EST
Hi Guenter
On 03-01-2023 05:56 pm, Guenter Roeck wrote:
On Tue, Jan 03, 2023 at 12:18:49PM +0530, Naresh Solanki wrote:
Hi Guenter,
On 29-12-2022 08:10 pm, Guenter Roeck wrote:
On Wed, Dec 14, 2022 at 09:07:11AM +0100, Naresh Solanki wrote:
From: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
Implement PMBUS irq handler.
Signed-off-by: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
Signed-off-by: Naresh Solanki <Naresh.Solanki@xxxxxxxxxxxxx>
$ scripts/checkpatch.pl --strict index.html
CHECK: Blank lines aren't necessary after an open brace '{'
#131: FILE: drivers/hwmon/pmbus/pmbus_core.c:3088:
+ for (i = 0; i < data->info->pages; i++) {
+
CHECK: Alignment should match open parenthesis
#183: FILE: drivers/hwmon/pmbus/pmbus_core.c:3140:
+ ret = devm_request_threaded_irq(dev, client->irq, NULL, pmbus_fault_handler,
+ 0, "pmbus-irq", data);
CHECK: Please use a blank line after function/struct/union/enum declarations
#197: FILE: drivers/hwmon/pmbus/pmbus_core.c:3154:
}
+static int pmbus_irq_setup(struct i2c_client *client, struct pmbus_data *data)
total: 0 errors, 0 warnings, 3 checks, 109 lines checked
NOTE: For some of the reported defects, checkpatch may be able to
mechanically convert to the typical style using --fix or --fix-inplace.
index.html has style problems, please review.
Please run checkpatch --strict on your patches.
Also see Documentation/hwmon/submitting-patches.rst.
I will take care of these errors in the updated version.
---
drivers/hwmon/pmbus/pmbus.h | 2 +-
drivers/hwmon/pmbus/pmbus_core.c | 84 ++++++++++++++++++++++++++++++++
2 files changed, 85 insertions(+), 1 deletion(-)
base-commit: 364ffd2537c44cb6914ff5669153f4a86fffad29
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 95e95783972a..244fd2597252 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -3072,11 +3072,89 @@ 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;
+
+ for (i = 0; i < data->info->pages; i++) {
+
+ mutex_lock(&data->update_lock);
+ 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_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);
This concerns me. It might mean that the chip does not support
PMBUS_SMBALERT_MASK. If so, there would be lots of error messages.
After going through the PMBus specification, it appears that this should not
be an issue unless there is a violation of the specification.
PMBus chips have lots of issues which violate the specification.
Have a look at the various drivers and the workarounds implemented there.
You'll need to check if the command/register is supported before using it.
Also, if you want to keep the error message, make it dev_err_once().
Either case, an error is an error, not to be ignored. An error here
should result in an error abort.
Yes, I agree that PMBus chips can have issues that violate the
specification, and that it is important to check whether a command or
register is supported before using it.
I have noticed that many drivers use the PMBUS_HAVE_* flags to expose
the presence of specific registers, and I think it would be a good idea
to add a PMBUS_HAVE_SMBALERT flag as well, so that drivers for supported
chips can use it to determine whether they should set up an IRQ handler
or not. If PMBUS_HAVE_SMBALERT is set, then the IRQ handler should be
set up, otherwise it should be ignored.
Will this approach be right?
+ }
+
+ 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);
Why check the return value from pmbus_write_smbalert_mask above but not here ?
Thank you for pointing out the oversight. I will make sure to include an
error check at this point.
+ 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 */
The comment does not make sense. pmbus_irq_setup() is not called
if the interrupt "is not given".
Yes. The comment here is not relevant and will be removed.
+ 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);
This is not a warning, it is an error.
Thank you for bringing this to my attention. I will make sure to update the
code to reflect that this is an error.
+ return ret;
+ }
+
+ return 0;
+}
+
#else
This is still in regulator code. I said several times that this is not
acceptable.
Thank you for pointing out the mistake. I will make sure to correct this in
the next revision.
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;
+}
#endif
static struct dentry *pmbus_debugfs_dir; /* pmbus debugfs directory */
@@ -3441,6 +3519,12 @@ 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");
Thanks,
Naresh