| Message ID | 1641996862-26960-1-git-send-email-akhilrajeev@nvidia.com |
|---|---|
| Headers | show |
| Series | Enable named interrupt smbus-alert for ACPI | expand |
On Wed, Jan 12, 2022 at 4:15 PM Akhil R <akhilrajeev@nvidia.com> wrote: > > Change of_*() functions to device_*() for firmware agnostic usage. > This allows to have smbus_alert interrupt without any changes the smbus_alert > in the controller drivers using ACPI table. the ACPI ... This change reveals potential issue: > - irq = of_irq_get_byname(adapter->dev.of_node, "smbus_alert"); > + irq = device_irq_get_byname(adapter->dev.parent, "smbus_alert"); > if (irq <= 0) I guess this '= 0' part should be fixed first. > return irq;
On Wed, Jan 12, 2022 at 4:14 PM Akhil R <akhilrajeev@nvidia.com> wrote: > > I2C - SMBus core drivers use named interrupts to support smbus_alert. > As named interrupts are not available for ACPI based systems, it was > required to change the i2c bus controller driver if to use smbus alert. > These patches provide option for named interrupts in ACPI and make the > implementation similar to DT. This will enable use of interrupt named > 'smbus-alert' in ACPI as well which will be taken during i2c adapter > register. Most of my comments are regarding spelling and documentation. The code looks almost good enough. That said, if maintainers will be okay, I'm sure the next version will be upstream-ready. Thanks!
> On Wed, Jan 12, 2022 at 3:14 PM Akhil R <akhilrajeev@nvidia.com> wrote: > > > > Get interrupt by name from ACPI table as well. > > > > Add option to use 'interrupt-names' in _DSD which can map to interrupt > > by index. The implementation is similar to 'interrupt-names' in devicetree. > > Also add a common routine to get irq by name from devicetree and ACPI > > table. > > > > Signed-off-by: Akhil R <akhilrajeev@nvidia.com> > > --- > > drivers/base/property.c | 35 +++++++++++++++++++++++++++++++++++ > > include/linux/property.h | 3 +++ > > 2 files changed, 38 insertions(+) > > > > diff --git a/drivers/base/property.c b/drivers/base/property.c index > > cbe4fa2..414c316 100644 > > --- a/drivers/base/property.c > > +++ b/drivers/base/property.c > > @@ -920,6 +920,41 @@ int fwnode_irq_get(const struct fwnode_handle > > *fwnode, unsigned int index) EXPORT_SYMBOL(fwnode_irq_get); > > > > /** > > + * fwnode_irq_get_byname - Get IRQ from a fwnode using its name > > + * @fwnode: Pointer to the firmware node > > + * @name: IRQ name in interrupt-names property in fwnode > > + * > > + * Returns Linux IRQ number on success, errno otherwise. > > + */ > > +int fwnode_irq_get_byname(const struct fwnode_handle *fwnode, const > > +char *name) { > > + int index; > > + > > + if (unlikely(!name)) > > + return -EINVAL; > > + > > + index = fwnode_property_match_string(fwnode, "interrupt-names", > name); > > + if (index < 0) > > + return index; > > + > > + return fwnode_irq_get(fwnode, index); } > > +EXPORT_SYMBOL(fwnode_irq_get_byname); > > + > > +/** > > + * device_irq_get_byname - Get IRQ of a device using interrupt name > > + * @dev: Device to get the interrupt > > + * @name: IRQ name in interrupt-names property in fwnode > > Which fwnode? > > > + * > > + * Returns Linux IRQ number on success, errno otherwise. > > + */ > > +int device_irq_get_byname(struct device *dev, const char *name) { > > + return fwnode_irq_get_byname(dev_fwnode(dev), name); } > > +EXPORT_SYMBOL_GPL(device_irq_get_byname); > > This can be confusing, because it pretends to be super-generic and in fact it > depends on an fwnode to be there. > > I guess I'd rather not have it at all, or use a more precise name for it. But, I suppose, the other device_*() functions also depend on the fwnode. Wouldn't it make the naming inconsistent if we add a different one here? Would it be better if I add more details in the description comment?
> On Wed, Jan 12, 2022 at 4:15 PM Akhil R <akhilrajeev@nvidia.com> wrote: > > > > Change of_*() functions to device_*() for firmware agnostic usage. > > This allows to have smbus_alert interrupt without any changes > > the smbus_alert > > > in the controller drivers using ACPI table. > > the ACPI > > ... > > This change reveals potential issue: > > > - irq = of_irq_get_byname(adapter->dev.of_node, "smbus_alert"); > > + irq = device_irq_get_byname(adapter->dev.parent, "smbus_alert"); > > > if (irq <= 0) > > I guess this '= 0' part should be fixed first. '0' is a failure as per the documentation of of_irq_get_byname() as well as of_irq_get(). The case is different for acpi_irq_get(), but it is handled in fwnode_irq_get(). If I understood it right, a return value of '0' should be considered a failure here. Thanks, Akhil
On Thu, Jan 20, 2022 at 11:48 AM Akhil R <akhilrajeev@nvidia.com> wrote: > > On Wed, Jan 12, 2022 at 4:15 PM Akhil R <akhilrajeev@nvidia.com> wrote: ... > > This change reveals potential issue: > > > > > - irq = of_irq_get_byname(adapter->dev.of_node, "smbus_alert"); > > > + irq = device_irq_get_byname(adapter->dev.parent, "smbus_alert"); > > > > > if (irq <= 0) > > > > I guess this '= 0' part should be fixed first. > > '0' is a failure as per the documentation of of_irq_get_byname() as well as > of_irq_get(). The case is different for acpi_irq_get(), but it is handled in > fwnode_irq_get(). If I understood it right, a return value of '0' should be > considered a failure here. Depends. I have no idea what the original code does here. But returning an error or 0 from this function seems confusing to me.
> ... > > > > This change reveals potential issue: > > > > > > > - irq = of_irq_get_byname(adapter->dev.of_node, "smbus_alert"); > > > > + irq = device_irq_get_byname(adapter->dev.parent, > "smbus_alert"); > > > > > > > if (irq <= 0) > > > > > > I guess this '= 0' part should be fixed first. > > > > '0' is a failure as per the documentation of of_irq_get_byname() as well as > > of_irq_get(). The case is different for acpi_irq_get(), but it is handled in > > fwnode_irq_get(). If I understood it right, a return value of '0' should be > > considered a failure here. > > Depends. I have no idea what the original code does here. But > returning an error or 0 from this function seems confusing to me. > The description in of_irq_get*() says - /* Return: Linux IRQ number on success, or 0 on the IRQ mapping failure, or * -EPROBE_DEFER if the IRQ domain is not yet created, or error code in case * of any other failure. */ As I see from the code of fwnode_irq_get(), which is used in this case, returns either the return value of of_irq_get() or error code from acpi_irq_get() when it fails, or res.start if it didn't fail. I guess, any of these would not be 0 unless there is an error. Thanks, Akhil
On Thu, Jan 20, 2022 at 12:29 PM Akhil R <akhilrajeev@nvidia.com> wrote: > > > ... > > > > > > This change reveals potential issue: > > > > > > > > > - irq = of_irq_get_byname(adapter->dev.of_node, "smbus_alert"); > > > > > + irq = device_irq_get_byname(adapter->dev.parent, > > "smbus_alert"); > > > > > > > > > if (irq <= 0) > > > > > > > > I guess this '= 0' part should be fixed first. > > > > > > '0' is a failure as per the documentation of of_irq_get_byname() as well as > > > of_irq_get(). The case is different for acpi_irq_get(), but it is handled in > > > fwnode_irq_get(). If I understood it right, a return value of '0' should be > > > considered a failure here. > > > > Depends. I have no idea what the original code does here. But > > returning an error or 0 from this function seems confusing to me. > > > The description in of_irq_get*() says - > /* Return: Linux IRQ number on success, or 0 on the IRQ mapping failure, or > * -EPROBE_DEFER if the IRQ domain is not yet created, or error code in case > * of any other failure. > */ > As I see from the code of fwnode_irq_get(), which is used in this case, returns > either the return value of of_irq_get() or error code from acpi_irq_get() when > it fails, or res.start if it didn't fail. I guess, any of these would not be 0 unless > there is an error. of_irq_get*() seems inconsistent... Uwe, what do you think?
> > > ... > > > > > > > > This change reveals potential issue: > > > > > > > > > > > - irq = of_irq_get_byname(adapter->dev.of_node, > "smbus_alert"); > > > > > > + irq = > > > > > > + device_irq_get_byname(adapter->dev.parent, > > > "smbus_alert"); > > > > > > > > > > > if (irq <= 0) > > > > > > > > > > I guess this '= 0' part should be fixed first. > > > > > > > > '0' is a failure as per the documentation of of_irq_get_byname() > > > > as well as of_irq_get(). The case is different for acpi_irq_get(), > > > > but it is handled in fwnode_irq_get(). If I understood it right, a > > > > return value of '0' should be considered a failure here. > > > > > > Depends. I have no idea what the original code does here. But > > > returning an error or 0 from this function seems confusing to me. > > > > > The description in of_irq_get*() says - > > /* Return: Linux IRQ number on success, or 0 on the IRQ mapping > > failure, or > > * -EPROBE_DEFER if the IRQ domain is not yet created, or error code > > in case > > * of any other failure. > > */ > > As I see from the code of fwnode_irq_get(), which is used in this > > case, returns either the return value of of_irq_get() or error code > > from acpi_irq_get() when it fails, or res.start if it didn't fail. I > > guess, any of these would not be 0 unless there is an error. > > of_irq_get*() seems inconsistent... > > Uwe, what do you think? > A bit tricky. You are right, as we don't often see a return value of '0' as an error in Linux. But here since it is a number which is expected, it might be reasonable to allot 0 to an error as well. Not sure of the exact rationale in those functions though. Thanks, Akhil
On Thu, Jan 20, 2022 at 12:43:02PM +0200, Andy Shevchenko wrote: > On Thu, Jan 20, 2022 at 12:29 PM Akhil R <akhilrajeev@nvidia.com> wrote: > > > > > ... > > > > > > > > This change reveals potential issue: > > > > > > > > > > > - irq = of_irq_get_byname(adapter->dev.of_node, "smbus_alert"); > > > > > > + irq = device_irq_get_byname(adapter->dev.parent, > > > "smbus_alert"); > > > > > > > > > > > if (irq <= 0) > > > > > > > > > > I guess this '= 0' part should be fixed first. > > > > > > > > '0' is a failure as per the documentation of of_irq_get_byname() as well as > > > > of_irq_get(). The case is different for acpi_irq_get(), but it is handled in > > > > fwnode_irq_get(). If I understood it right, a return value of '0' should be > > > > considered a failure here. > > > > > > Depends. I have no idea what the original code does here. But > > > returning an error or 0 from this function seems confusing to me. > > > > > The description in of_irq_get*() says - > > /* Return: Linux IRQ number on success, or 0 on the IRQ mapping failure, or > > * -EPROBE_DEFER if the IRQ domain is not yet created, or error code in case > > * of any other failure. > > */ > > As I see from the code of fwnode_irq_get(), which is used in this case, returns > > either the return value of of_irq_get() or error code from acpi_irq_get() when > > it fails, or res.start if it didn't fail. I guess, any of these would not be 0 unless > > there is an error. > > of_irq_get*() seems inconsistent... > > Uwe, what do you think? Yeah, this is something I stumbled over during the platform_get_irq*() discussion. But I don't feel like investing any more energy there. Best regards Uwe