| Message ID | 20230319204802.1364-4-kaehndan@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Jiri Kosina |
| Headers | show |
| Series | Firmware Support for USB-HID Devices and CP2112 | expand |
On Sun, Mar 19, 2023 at 03:48:02PM -0500, Danny Kaehn wrote: > Support describing the CP2112's I2C and GPIO interfaces in firmware. > > I2C and GPIO child nodes can either be children with names "i2c" and > "gpio", or, for ACPI, device nodes with _ADR Zero and One, > respectively. > > Additionally, support configuring the I2C bus speed from the > clock-frequency device property. Thank you for the update, my comments below. ... > + struct i2c_timings timings; > + struct fwnode_handle *child; Longer line first easier to read. > + u32 addr; > + const char *name; Ditto. ... > + device_for_each_child_node(&hdev->dev, child) { > + name = fwnode_get_name(child); > + ret = acpi_get_local_address(ACPI_HANDLE_FWNODE(child), &addr); > + > + if ((name && strcmp("i2c", name) == 0) || (!ret && addr == 0)) > + device_set_node(&dev->adap.dev, child); > + else if ((name && strcmp("gpio", name)) == 0 || > + (!ret && addr == 1)) > + dev->gc.fwnode = child; > + } Please, make addresses defined explicitly. You may also do it with node naming schema: #define CP2112_I2C_ADR 0 #define CP2112_GPIO_ADR 1 static const char * const cp2112_cell_names[] = { [CP2112_I2C_ADR] = "i2c", [CP2112_GPIO_ADR] = "gpio", }; device_for_each_child_node(&hdev->dev, child) { name = fwnode_get_name(child); if (name) { ret = match_string(cp2112_cell_names, ARRAY_SIZE(cp2112_cell_names), name); if (ret >= 0) addr = ret; } else ret = acpi_get_local_address(ACPI_HANDLE_FWNODE(child), &addr); if (ret < 0) ...error handling if needed... switch (addr) { case CP2112_I2C_ADR: device_set_node(&dev->adap.dev, child); break; case CP2112_GPIO_ADR: dev->gc.fwnode = child; break; default: ...error handling... } }
On Mon, Mar 20, 2023 at 02:58:07PM +0200, Andy Shevchenko wrote: > On Sun, Mar 19, 2023 at 03:48:02PM -0500, Danny Kaehn wrote: ... > > + device_for_each_child_node(&hdev->dev, child) { > > + name = fwnode_get_name(child); > > + ret = acpi_get_local_address(ACPI_HANDLE_FWNODE(child), &addr); > > + > > + if ((name && strcmp("i2c", name) == 0) || (!ret && addr == 0)) > > + device_set_node(&dev->adap.dev, child); > > + else if ((name && strcmp("gpio", name)) == 0 || > > + (!ret && addr == 1)) > > + dev->gc.fwnode = child; > > + } > > Please, make addresses defined explicitly. You may also do it with node naming > schema: > > #define CP2112_I2C_ADR 0 > #define CP2112_GPIO_ADR 1 > > static const char * const cp2112_cell_names[] = { > [CP2112_I2C_ADR] = "i2c", > [CP2112_GPIO_ADR] = "gpio", > }; > > device_for_each_child_node(&hdev->dev, child) { > name = fwnode_get_name(child); > if (name) { > ret = match_string(cp2112_cell_names, ARRAY_SIZE(cp2112_cell_names), name); > if (ret >= 0) > addr = ret; > } else > ret = acpi_get_local_address(ACPI_HANDLE_FWNODE(child), &addr); > if (ret < 0) > ...error handling if needed... > > switch (addr) { > case CP2112_I2C_ADR: > device_set_node(&dev->adap.dev, child); > break; > case CP2112_GPIO_ADR: > dev->gc.fwnode = child; > break; > default: > ...error handling... > } > } Btw, don't you use "reg" property for the child nodes? It would be better from de facto used patterns (we have a couple of mode drivers that have a common code to read "reg" or _ADR() and that code can be split into a helper and used here).
On Mon, Mar 20, 2023 at 8:00 AM Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote: > > On Mon, Mar 20, 2023 at 02:58:07PM +0200, Andy Shevchenko wrote: > > On Sun, Mar 19, 2023 at 03:48:02PM -0500, Danny Kaehn wrote: > > ... > > > > + device_for_each_child_node(&hdev->dev, child) { > > > + name = fwnode_get_name(child); > > > + ret = acpi_get_local_address(ACPI_HANDLE_FWNODE(child), &addr); > > > + > > > + if ((name && strcmp("i2c", name) == 0) || (!ret && addr == 0)) > > > + device_set_node(&dev->adap.dev, child); > > > + else if ((name && strcmp("gpio", name)) == 0 || > > > + (!ret && addr == 1)) > > > + dev->gc.fwnode = child; > > > + } > > > > Please, make addresses defined explicitly. You may also do it with node naming > > schema: > > > > #define CP2112_I2C_ADR 0 > > #define CP2112_GPIO_ADR 1 > > > > static const char * const cp2112_cell_names[] = { > > [CP2112_I2C_ADR] = "i2c", > > [CP2112_GPIO_ADR] = "gpio", > > }; > > > > device_for_each_child_node(&hdev->dev, child) { > > name = fwnode_get_name(child); > > if (name) { > > ret = match_string(cp2112_cell_names, ARRAY_SIZE(cp2112_cell_names), name); > > if (ret >= 0) > > addr = ret; > > } else > > ret = acpi_get_local_address(ACPI_HANDLE_FWNODE(child), &addr); > > if (ret < 0) > > ...error handling if needed... > > > > switch (addr) { > > case CP2112_I2C_ADR: > > device_set_node(&dev->adap.dev, child); > > break; > > case CP2112_GPIO_ADR: > > dev->gc.fwnode = child; > > break; > > default: > > ...error handling... > > } > > } > > Btw, don't you use "reg" property for the child nodes? It would be better from > de facto used patterns (we have a couple of mode drivers that have a common > code to read "reg" or _ADR() and that code can be split into a helper and used > here). > Named nodes _seem_ to be preferred in DT for when there isn't a logical / natural numbering to the child nodes. A.e. for USB, reg is used to specify which port, for I2C, which address on the bus, but for two parallel and independent functions on the same device, it seems named nodes would make more sense in DT. Many examples exist in mainline where named nodes are used in DT in this way. One example is network cards which provide an mdio bus bind through the child "mdio". One example of a specifically a child i2c controller being bound to "i2c" can be found in pine64,pinephone-keyboard.yaml. But it's certainly possible this isn't the desired direction moving forward in DT -- my opinion should definitely be taken with a grain of salt. Maybe this is something I should follow up on with DT folks on that DT vs. ACPI thread made earlier. One thing I did notice when looking at the mfd subsystem is that most DT drivers actually match on the compatible string of the child nodes, a.e. "silabs,cp2112", "silabs,cp2112-gpio". "silabs,cp2112-i2c". We could implement that here, but I think that would make more sense if we were to actually split the cp2112 into mfd & platform drivers, and additionally split the DT binding by function. Thanks, Danny Kaehn
On Mon, Mar 20, 2023 at 08:40:07AM -0500, Daniel Kaehn wrote: > On Mon, Mar 20, 2023 at 8:00 AM Andy Shevchenko > <andriy.shevchenko@linux.intel.com> wrote: > > On Mon, Mar 20, 2023 at 02:58:07PM +0200, Andy Shevchenko wrote: > > > On Sun, Mar 19, 2023 at 03:48:02PM -0500, Danny Kaehn wrote: ... > > > > + device_for_each_child_node(&hdev->dev, child) { > > > > + name = fwnode_get_name(child); > > > > + ret = acpi_get_local_address(ACPI_HANDLE_FWNODE(child), &addr); > > > > + > > > > + if ((name && strcmp("i2c", name) == 0) || (!ret && addr == 0)) > > > > + device_set_node(&dev->adap.dev, child); > > > > + else if ((name && strcmp("gpio", name)) == 0 || > > > > + (!ret && addr == 1)) > > > > + dev->gc.fwnode = child; > > > > + } > > > > > > Please, make addresses defined explicitly. You may also do it with node naming > > > schema: > > > > > > #define CP2112_I2C_ADR 0 > > > #define CP2112_GPIO_ADR 1 > > > > > > static const char * const cp2112_cell_names[] = { > > > [CP2112_I2C_ADR] = "i2c", > > > [CP2112_GPIO_ADR] = "gpio", > > > }; > > > > > > device_for_each_child_node(&hdev->dev, child) { > > > name = fwnode_get_name(child); > > > if (name) { > > > ret = match_string(cp2112_cell_names, ARRAY_SIZE(cp2112_cell_names), name); > > > if (ret >= 0) > > > addr = ret; > > > } else > > > ret = acpi_get_local_address(ACPI_HANDLE_FWNODE(child), &addr); > > > if (ret < 0) > > > ...error handling if needed... > > > > > > switch (addr) { > > > case CP2112_I2C_ADR: > > > device_set_node(&dev->adap.dev, child); > > > break; > > > case CP2112_GPIO_ADR: > > > dev->gc.fwnode = child; > > > break; > > > default: > > > ...error handling... > > > } > > > } > > > > Btw, don't you use "reg" property for the child nodes? It would be better from > > de facto used patterns (we have a couple of mode drivers that have a common > > code to read "reg" or _ADR() and that code can be split into a helper and used > > here). > > > > Named nodes _seem_ to be preferred in DT for when there isn't a logical / > natural numbering to the child nodes. A.e. for USB, reg is used to specify > which port, for I2C, which address on the bus, but for two parallel and > independent functions on the same device, it seems named nodes would make > more sense in DT. Many examples exist in mainline where named nodes are used > in DT in this way. Okay, I'm not an expert in the DT preferable schemas, so I believe DT people should answer on this. > One example is network cards which provide an mdio bus > bind through the child "mdio". One example of a specifically a > child i2c controller being bound to "i2c" can be found in > pine64,pinephone-keyboard.yaml. > But it's certainly possible this isn't the desired direction moving forward > in DT -- my opinion should definitely be taken with a grain of salt. Maybe > this is something I should follow up on with DT folks on that DT vs. ACPI > thread made earlier. > > One thing I did notice when looking at the mfd subsystem is that most DT > drivers actually match on the compatible string of the child nodes, a.e. > "silabs,cp2112", "silabs,cp2112-gpio". "silabs,cp2112-i2c". We could > implement that here, but I think that would make more sense if we were to > actually split the cp2112 into mfd & platform drivers, and additionally split > the DT binding by function. IIRC (but might be very well mistaken) the compatible strings for children are discouraged.
On Mon, Mar 20, 2023 at 9:10 AM Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote: > > On Mon, Mar 20, 2023 at 08:40:07AM -0500, Daniel Kaehn wrote: > > On Mon, Mar 20, 2023 at 8:00 AM Andy Shevchenko > > <andriy.shevchenko@linux.intel.com> wrote: > > > On Mon, Mar 20, 2023 at 02:58:07PM +0200, Andy Shevchenko wrote: > > > > On Sun, Mar 19, 2023 at 03:48:02PM -0500, Danny Kaehn wrote: > > ... > > > > > > + device_for_each_child_node(&hdev->dev, child) { > > > > > + name = fwnode_get_name(child); > > > > > + ret = acpi_get_local_address(ACPI_HANDLE_FWNODE(child), &addr); > > > > > + > > > > > + if ((name && strcmp("i2c", name) == 0) || (!ret && addr == 0)) > > > > > + device_set_node(&dev->adap.dev, child); > > > > > + else if ((name && strcmp("gpio", name)) == 0 || > > > > > + (!ret && addr == 1)) > > > > > + dev->gc.fwnode = child; > > > > > + } > > > > > > > > Please, make addresses defined explicitly. You may also do it with node naming > > > > schema: > > > > > > > > #define CP2112_I2C_ADR 0 > > > > #define CP2112_GPIO_ADR 1 > > > > > > > > static const char * const cp2112_cell_names[] = { > > > > [CP2112_I2C_ADR] = "i2c", > > > > [CP2112_GPIO_ADR] = "gpio", > > > > }; > > > > > > > > device_for_each_child_node(&hdev->dev, child) { > > > > name = fwnode_get_name(child); > > > > if (name) { > > > > ret = match_string(cp2112_cell_names, ARRAY_SIZE(cp2112_cell_names), name); > > > > if (ret >= 0) > > > > addr = ret; > > > > } else > > > > ret = acpi_get_local_address(ACPI_HANDLE_FWNODE(child), &addr); > > > > if (ret < 0) > > > > ...error handling if needed... > > > > > > > > switch (addr) { > > > > case CP2112_I2C_ADR: > > > > device_set_node(&dev->adap.dev, child); > > > > break; > > > > case CP2112_GPIO_ADR: > > > > dev->gc.fwnode = child; > > > > break; > > > > default: > > > > ...error handling... > > > > } > > > > } > > > > > > Btw, don't you use "reg" property for the child nodes? It would be better from > > > de facto used patterns (we have a couple of mode drivers that have a common > > > code to read "reg" or _ADR() and that code can be split into a helper and used > > > here). > > > > > > > Named nodes _seem_ to be preferred in DT for when there isn't a logical / > > natural numbering to the child nodes. A.e. for USB, reg is used to specify > > which port, for I2C, which address on the bus, but for two parallel and > > independent functions on the same device, it seems named nodes would make > > more sense in DT. Many examples exist in mainline where named nodes are used > > in DT in this way. > > Okay, I'm not an expert in the DT preferable schemas, so I believe DT people > should answer on this. > Hello, Thanks for all the time spent reviewing this thus far. Following up to see what my next steps might be. It sounds like we might want some DT folks to weigh in on the strategy used for identifying the child I2C and GPIO nodes for the CP2112 device before moving further toward applying this. Since the DT list is on this thread (as well as Rob+Krzystof), and this has sat for a little while, I'm assuming that the ball is in my court to seek out an answer/opinion here. (I know folks get a lot of email, so apologies if the correct move would have been to wait a bit longer before following up! Not intending to be rude.) Would it be appropriate / expected that I send a separate email thread to the DT mailing list on their opinion here? Or would that create more confusion/complexity in adding yet another thread? I did create a separate email thread for the initial DT vs. ACPI conversation we had about accessing children by name or index in a unified way due to the differences in upper/lower case and use-cases, but that (understandably) didn't seem to gain any traction. Thanks for any insights! Thanks, Danny Kaehn > > One example is network cards which provide an mdio bus > > bind through the child "mdio". One example of a specifically a > > child i2c controller being bound to "i2c" can be found in > > pine64,pinephone-keyboard.yaml. > > But it's certainly possible this isn't the desired direction moving forward > > in DT -- my opinion should definitely be taken with a grain of salt. Maybe > > this is something I should follow up on with DT folks on that DT vs. ACPI > > thread made earlier. > > > > One thing I did notice when looking at the mfd subsystem is that most DT > > drivers actually match on the compatible string of the child nodes, a.e. > > "silabs,cp2112", "silabs,cp2112-gpio". "silabs,cp2112-i2c". We could > > implement that here, but I think that would make more sense if we were to > > actually split the cp2112 into mfd & platform drivers, and additionally split > > the DT binding by function. > > IIRC (but might be very well mistaken) the compatible strings for children > are discouraged. > > -- > With Best Regards, > Andy Shevchenko > >
+Cc: Niyas, who is working a lot on filling the gaps in ACPI in comparison
to DT in the Linux kernel. Perhaps he has some ideas or even better
solutions.
On Mon, May 01, 2023 at 06:35:44PM -0500, Daniel Kaehn wrote:
> On Mon, Mar 20, 2023 at 9:10 AM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> > On Mon, Mar 20, 2023 at 08:40:07AM -0500, Daniel Kaehn wrote:
> > > On Mon, Mar 20, 2023 at 8:00 AM Andy Shevchenko
> > > <andriy.shevchenko@linux.intel.com> wrote:
> > > > On Mon, Mar 20, 2023 at 02:58:07PM +0200, Andy Shevchenko wrote:
> > > > > On Sun, Mar 19, 2023 at 03:48:02PM -0500, Danny Kaehn wrote:
...
> > > > > > + device_for_each_child_node(&hdev->dev, child) {
> > > > > > + name = fwnode_get_name(child);
> > > > > > + ret = acpi_get_local_address(ACPI_HANDLE_FWNODE(child), &addr);
> > > > > > +
> > > > > > + if ((name && strcmp("i2c", name) == 0) || (!ret && addr == 0))
> > > > > > + device_set_node(&dev->adap.dev, child);
> > > > > > + else if ((name && strcmp("gpio", name)) == 0 ||
> > > > > > + (!ret && addr == 1))
> > > > > > + dev->gc.fwnode = child;
> > > > > > + }
> > > > >
> > > > > Please, make addresses defined explicitly. You may also do it with node naming
> > > > > schema:
> > > > >
> > > > > #define CP2112_I2C_ADR 0
> > > > > #define CP2112_GPIO_ADR 1
> > > > >
> > > > > static const char * const cp2112_cell_names[] = {
> > > > > [CP2112_I2C_ADR] = "i2c",
> > > > > [CP2112_GPIO_ADR] = "gpio",
> > > > > };
> > > > >
> > > > > device_for_each_child_node(&hdev->dev, child) {
> > > > > name = fwnode_get_name(child);
> > > > > if (name) {
> > > > > ret = match_string(cp2112_cell_names, ARRAY_SIZE(cp2112_cell_names), name);
> > > > > if (ret >= 0)
> > > > > addr = ret;
> > > > > } else
> > > > > ret = acpi_get_local_address(ACPI_HANDLE_FWNODE(child), &addr);
> > > > > if (ret < 0)
> > > > > ...error handling if needed...
> > > > >
> > > > > switch (addr) {
> > > > > case CP2112_I2C_ADR:
> > > > > device_set_node(&dev->adap.dev, child);
> > > > > break;
> > > > > case CP2112_GPIO_ADR:
> > > > > dev->gc.fwnode = child;
> > > > > break;
> > > > > default:
> > > > > ...error handling...
> > > > > }
> > > > > }
> > > >
> > > > Btw, don't you use "reg" property for the child nodes? It would be better from
> > > > de facto used patterns (we have a couple of mode drivers that have a common
> > > > code to read "reg" or _ADR() and that code can be split into a helper and used
> > > > here).
> > >
> > > Named nodes _seem_ to be preferred in DT for when there isn't a logical /
> > > natural numbering to the child nodes. A.e. for USB, reg is used to specify
> > > which port, for I2C, which address on the bus, but for two parallel and
> > > independent functions on the same device, it seems named nodes would make
> > > more sense in DT. Many examples exist in mainline where named nodes are used
> > > in DT in this way.
> >
> > Okay, I'm not an expert in the DT preferable schemas, so I believe DT people
> > should answer on this.
>
> Hello,
>
> Thanks for all the time spent reviewing this thus far. Following up to
> see what my next steps might be.
>
> It sounds like we might want some DT folks to weigh in on the strategy
> used for identifying the child I2C and GPIO nodes for the CP2112
> device before moving further toward applying this.
>
> Since the DT list is on this thread (as well as Rob+Krzystof), and
> this has sat for a little while, I'm assuming that the ball is in my
> court to seek out an answer/opinion here. (I know folks get a lot of
> email, so apologies if the correct move would have been to wait a bit
> longer before following up! Not intending to be rude.)
>
> Would it be appropriate / expected that I send a separate email thread
> to the DT mailing list on their opinion here? Or would that create
> more confusion/complexity in adding yet another thread? I did create a
> separate email thread for the initial DT vs. ACPI conversation we had
> about accessing children by name or index in a unified way due to the
> differences in upper/lower case and use-cases, but that
> (understandably) didn't seem to gain any traction.
>
> Thanks for any insights!
>
> Thanks,
> Danny Kaehn
>
> > > One example is network cards which provide an mdio bus
> > > bind through the child "mdio". One example of a specifically a
> > > child i2c controller being bound to "i2c" can be found in
> > > pine64,pinephone-keyboard.yaml.
> > > But it's certainly possible this isn't the desired direction moving forward
> > > in DT -- my opinion should definitely be taken with a grain of salt. Maybe
> > > this is something I should follow up on with DT folks on that DT vs. ACPI
> > > thread made earlier.
> > >
> > > One thing I did notice when looking at the mfd subsystem is that most DT
> > > drivers actually match on the compatible string of the child nodes, a.e.
> > > "silabs,cp2112", "silabs,cp2112-gpio". "silabs,cp2112-i2c". We could
> > > implement that here, but I think that would make more sense if we were to
> > > actually split the cp2112 into mfd & platform drivers, and additionally split
> > > the DT binding by function.
> >
> > IIRC (but might be very well mistaken) the compatible strings for children
> > are discouraged.
Hello folks, wanted to give one more follow up on this patch/discussion. Would a reasonable next step for me to help nudge this forward be to submit a v10 addressing Andy's most recent code comments? Again hoping I'm not being rude or stepping on toes; just want to make sure I'm doing my dilligence to move things forward. I'll assume that going ahead and submitting a v10 with unresolved discussion here isn't a terrible offense if I don't end up getting a response here in the next week or so. Leaving some links to some of the more key points of the discussion across the versions of this patch, since it's been ~5 months since the last activity here. Discussion began with discussion of using child nodes by name across DT with ACPI, for binding fwnodes for the CP2112's I2C and GPIO controllers; since ACPI requires uppercase names (and names should specifically not be meaningful in ACPI) https://lore.kernel.org/all/Y%2F9oO1AE6GK6CQmp@smile.fi.intel.com/ Andy suggested I use _ADR to identify the child node by index for ACPI https://lore.kernel.org/all/ZAi4NjqXTbLpVhPo@smile.fi.intel.com/ v9 implemented matching by child node name OR by address depnding on the type of firmware used https://lore.kernel.org/all/20230319204802.1364-4-kaehndan@gmail.com/ Some additional discussion on whether matching child nodes by name is the best approach even for the DT side (also within the in-line body of this email) https://lore.kernel.org/all/ZBhoHzTr5l38u%2FkX@smile.fi.intel.com/ The DT binding patch in question https://lore.kernel.org/all/20230319204802.1364-2-kaehndan@gmail.com/ Thanks, Danny Kaehn On Mon, Jul 3 2023 at 13:57:22 +0300 Andy Shevchenko write: > On Mon, May 01, 2023 at 06:35:44PM -0500, Daniel Kaehn wrote: > > On Mon, Mar 20, 2023 at 9:10 AM Andy Shevchenko > > <andriy.shevchenko@linux.intel.com> wrote: > > > On Mon, Mar 20, 2023 at 08:40:07AM -0500, Daniel Kaehn wrote: > > > > On Mon, Mar 20, 2023 at 8:00 AM Andy Shevchenko > > > > <andriy.shevchenko@linux.intel.com> wrote: > > > > > On Mon, Mar 20, 2023 at 02:58:07PM +0200, Andy Shevchenko Wrote: > > > > > > On Sun, Mar 19, 2023 at 03:48:02PM -0500, Danny Kaehn wrote: > +Cc: Niyas, who is working a lot on filling the gaps in ACPI in comparison > to DT in the Linux kernel. Perhaps he has some ideas or even better > solutions. > > > ... > > > > > > > > + device_for_each_child_node(&hdev->dev, child) { > > > > > > > + name = fwnode_get_name(child); > > > > > > > + ret = acpi_get_local_address(ACPI_HANDLE_FWNODE(child), &addr); > > > > > > > + > > > > > > > + if ((name && strcmp("i2c", name) == 0) || (!ret && addr == 0)) > > > > > > > + device_set_node(&dev->adap.dev, child); > > > > > > > + else if ((name && strcmp("gpio", name)) == 0 || > > > > > > > + (!ret && addr == 1)) > > > > > > > + dev->gc.fwnode = child; > > > > > > > + } > > > > > > > > > > > > Please, make addresses defined explicitly. You may also do it with node naming > > > > > > schema: > > > > > > > > > > > > #define CP2112_I2C_ADR 0 > > > > > > #define CP2112_GPIO_ADR 1 > > > > > > > > > > > > static const char * const cp2112_cell_names[] = { > > > > > > [CP2112_I2C_ADR] = "i2c", > > > > > > [CP2112_GPIO_ADR] = "gpio", > > > > > > }; > > > > > > > > > > > > device_for_each_child_node(&hdev->dev, child) { > > > > > > name = fwnode_get_name(child); > > > > > > if (name) { > > > > > > ret = match_string(cp2112_cell_names, ARRAY_SIZE(cp2112_cell_names), name); > > > > > > if (ret >= 0) > > > > > > addr = ret; > > > > > > } else > > > > > > ret = acpi_get_local_address(ACPI_HANDLE_FWNODE(child), &addr); > > > > > > if (ret < 0) > > > > > > ...error handling if needed... > > > > > > > > > > > > switch (addr) { > > > > > > case CP2112_I2C_ADR: > > > > > > device_set_node(&dev->adap.dev, child); > > > > > > break; > > > > > > case CP2112_GPIO_ADR: > > > > > > dev->gc.fwnode = child; > > > > > > break; > > > > > > default: > > > > > > ...error handling... > > > > > > } > > > > > > } > > > > > > > > > > Btw, don't you use "reg" property for the child nodes? It would be better from > > > > > de facto used patterns (we have a couple of mode drivers that have a common > > > > > code to read "reg" or _ADR() and that code can be split into a helper and used > > > > > here). > > > > > > > > Named nodes _seem_ to be preferred in DT for when there isn't a logical / > > > > natural numbering to the child nodes. A.e. for USB, reg is used to specify > > > > which port, for I2C, which address on the bus, but for two parallel and > > > > independent functions on the same device, it seems named nodes would make > > > > more sense in DT. Many examples exist in mainline where named nodes are used > > > > in DT in this way. > > > > > > Okay, I'm not an expert in the DT preferable schemas, so I believe DT people > > > should answer on this. > > > > Hello, > > > > Thanks for all the time spent reviewing this thus far. Following up to > > see what my next steps might be. > > > > It sounds like we might want some DT folks to weigh in on the strategy > > used for identifying the child I2C and GPIO nodes for the CP2112 > > device before moving further toward applying this. > > > > Since the DT list is on this thread (as well as Rob+Krzystof), and > > this has sat for a little while, I'm assuming that the ball is in my > > court to seek out an answer/opinion here. (I know folks get a lot of > > email, so apologies if the correct move would have been to wait a bit > > longer before following up! Not intending to be rude.) > > > > Would it be appropriate / expected that I send a separate email thread > > to the DT mailing list on their opinion here? Or would that create > > more confusion/complexity in adding yet another thread? I did create a > > separate email thread for the initial DT vs. ACPI conversation we had > > about accessing children by name or index in a unified way due to the > > differences in upper/lower case and use-cases, but that > > (understandably) didn't seem to gain any traction. > > > > Thanks for any insights! > > > > Thanks, > > Danny Kaehn > > > > > > One example is network cards which provide an mdio bus > > > > bind through the child "mdio". One example of a specifically a > > > > child i2c controller being bound to "i2c" can be found in > > > > pine64,pinephone-keyboard.yaml. > > > > But it's certainly possible this isn't the desired direction moving forward > > > > in DT -- my opinion should definitely be taken with a grain of salt. Maybe > > > > this is something I should follow up on with DT folks on that DT vs. ACPI > > > > thread made earlier. > > > > > > > > One thing I did notice when looking at the mfd subsystem is that most DT > > > > drivers actually match on the compatible string of the child nodes, a.e. > > > > "silabs,cp2112", "silabs,cp2112-gpio". "silabs,cp2112-i2c". We could > > > > implement that here, but I think that would make more sense if we were to > > > > actually split the cp2112 into mfd & platform drivers, and additionally split > > > > the DT binding by function. > > > > > > IIRC (but might be very well mistaken) the compatible strings for children > > > are discouraged. >
Hi Danny, On Jan 17 2024, Danny Kaehn wrote: > Hello folks, wanted to give one more follow up on this > patch/discussion. Would a reasonable next step for me > to help nudge this forward be to submit a v10 addressing > Andy's most recent code comments? Again hoping I'm not being > rude or stepping on toes; just want to make sure I'm doing my > dilligence to move things forward. I'll assume that going ahead > and submitting a v10 with unresolved discussion here isn't a > terrible offense if I don't end up getting a response here in > the next week or so. Submitting a v10, even if there are still undecided points is definitely the way forward. People probably have forgot a lot of things there and need a refresh on the latest state of it :) > > Leaving some links to some of the more key points of the discussion > across the versions of this patch, since it's been ~5 months since > the last activity here. > > Discussion began with discussion of using child nodes by name > across DT with ACPI, for binding fwnodes for the CP2112's I2C > and GPIO controllers; since ACPI requires uppercase names (and > names should specifically not be meaningful in ACPI) > https://lore.kernel.org/all/Y%2F9oO1AE6GK6CQmp@smile.fi.intel.com/ I think the DT part is fine. Please resubmit it in v10, but probably drop the previous rev-by and explicitly mention you did so after the first '---' below your signed-off-by. This should re-trigger a review from them. Things may have changed since last year, and having another review would be beneficial IMO. > > Andy suggested I use _ADR to identify the child node by index > for ACPI > https://lore.kernel.org/all/ZAi4NjqXTbLpVhPo@smile.fi.intel.com/ I think I still prefer the "_DSD" approach with the cell-names, but OTOH, it's not like there is an official ACPI description for this, and we can basically define whatever we want. So please go ahead with the _ADR approach IMO, with a couple of changes: - mention about that in the DT bindings documentation - please add an enum with those 2 addresses (with kernel doc), to document it in the code and not have magic constants in your checks > > v9 implemented matching by child node name OR by address depnding > on the type of firmware used > https://lore.kernel.org/all/20230319204802.1364-4-kaehndan@gmail.com/ See my 2 comments above. FWIW, I think 2/3 could go directly in as well, but the timing is not ideal, we are in the middle of the Merge Window. > > Some additional discussion on whether matching child nodes by name > is the best approach even for the DT side > (also within the in-line body of this email) > https://lore.kernel.org/all/ZBhoHzTr5l38u%2FkX@smile.fi.intel.com/ Honestly, not sure we'll have too many users on the ACPI side (besides myself). So if you really feel uncomfortable, you can always put a warning that we are using _ADR in the ACPI world as a fallback, but that we might revisit that in the future (with naming, if we reach to an agreement). Cheers, Benjamin > > > The DT binding patch in question > https://lore.kernel.org/all/20230319204802.1364-2-kaehndan@gmail.com/ > > Thanks, > > Danny Kaehn > > > > > On Mon, Jul 3 2023 at 13:57:22 +0300 Andy Shevchenko write: > > On Mon, May 01, 2023 at 06:35:44PM -0500, Daniel Kaehn wrote: > > > On Mon, Mar 20, 2023 at 9:10 AM Andy Shevchenko > > > <andriy.shevchenko@linux.intel.com> wrote: > > > > On Mon, Mar 20, 2023 at 08:40:07AM -0500, Daniel Kaehn wrote: > > > > > On Mon, Mar 20, 2023 at 8:00 AM Andy Shevchenko > > > > > <andriy.shevchenko@linux.intel.com> wrote: > > > > > > On Mon, Mar 20, 2023 at 02:58:07PM +0200, Andy Shevchenko > Wrote: > > > > > > > On Sun, Mar 19, 2023 at 03:48:02PM -0500, Danny Kaehn > wrote: > > +Cc: Niyas, who is working a lot on filling the gaps in ACPI in > comparison > > to DT in the Linux kernel. Perhaps he has some ideas or even > better > > solutions. > > > > > > ... > > > > > > > > > > + device_for_each_child_node(&hdev->dev, child) { > > > > > > > > + name = fwnode_get_name(child); > > > > > > > > + ret = > acpi_get_local_address(ACPI_HANDLE_FWNODE(child), &addr); > > > > > > > > + > > > > > > > > + if ((name && strcmp("i2c", name) == 0) || > (!ret && addr == 0)) > > > > > > > > + device_set_node(&dev->adap.dev, > child); > > > > > > > > + else if ((name && strcmp("gpio", name)) == 0 > || > > > > > > > > + (!ret && addr == 1)) > > > > > > > > + dev->gc.fwnode = child; > > > > > > > > + } > > > > > > > > > > > > > > Please, make addresses defined explicitly. You may also do > it with node naming > > > > > > > schema: > > > > > > > > > > > > > > #define CP2112_I2C_ADR 0 > > > > > > > #define CP2112_GPIO_ADR 1 > > > > > > > > > > > > > > static const char * const cp2112_cell_names[] = { > > > > > > > [CP2112_I2C_ADR] = "i2c", > > > > > > > [CP2112_GPIO_ADR] = "gpio", > > > > > > > }; > > > > > > > > > > > > > > device_for_each_child_node(&hdev->dev, child) { > > > > > > > name = fwnode_get_name(child); > > > > > > > if (name) { > > > > > > > ret = match_string(cp2112_cell_names, > ARRAY_SIZE(cp2112_cell_names), name); > > > > > > > if (ret >= 0) > > > > > > > addr = ret; > > > > > > > } else > > > > > > > ret = > acpi_get_local_address(ACPI_HANDLE_FWNODE(child), &addr); > > > > > > > if (ret < 0) > > > > > > > ...error handling if needed... > > > > > > > > > > > > > > switch (addr) { > > > > > > > case CP2112_I2C_ADR: > > > > > > > device_set_node(&dev->adap.dev, > child); > > > > > > > break; > > > > > > > case CP2112_GPIO_ADR: > > > > > > > dev->gc.fwnode = child; > > > > > > > break; > > > > > > > default: > > > > > > > ...error handling... > > > > > > > } > > > > > > > } > > > > > > > > > > > > Btw, don't you use "reg" property for the child nodes? It > would be better from > > > > > > de facto used patterns (we have a couple of mode drivers that > have a common > > > > > > code to read "reg" or _ADR() and that code can be split into > a helper and used > > > > > > here). > > > > > > > > > > Named nodes _seem_ to be preferred in DT for when there isn't a > logical / > > > > > natural numbering to the child nodes. A.e. for USB, reg is used > to specify > > > > > which port, for I2C, which address on the bus, but for two > parallel and > > > > > independent functions on the same device, it seems named nodes > would make > > > > > more sense in DT. Many examples exist in mainline where named > nodes are used > > > > > in DT in this way. > > > > > > > > Okay, I'm not an expert in the DT preferable schemas, so I > believe DT people > > > > should answer on this. > > > > > > Hello, > > > > > > Thanks for all the time spent reviewing this thus far. Following up > to > > > see what my next steps might be. > > > > > > It sounds like we might want some DT folks to weigh in on the > strategy > > > used for identifying the child I2C and GPIO nodes for the CP2112 > > > device before moving further toward applying this. > > > > > > Since the DT list is on this thread (as well as Rob+Krzystof), and > > > this has sat for a little while, I'm assuming that the ball is in > my > > > court to seek out an answer/opinion here. (I know folks get a lot > of > > > email, so apologies if the correct move would have been to wait a > bit > > > longer before following up! Not intending to be rude.) > > > > > > Would it be appropriate / expected that I send a separate email > thread > > > to the DT mailing list on their opinion here? Or would that create > > > more confusion/complexity in adding yet another thread? I did > create a > > > separate email thread for the initial DT vs. ACPI conversation we > had > > > about accessing children by name or index in a unified way due to > the > > > differences in upper/lower case and use-cases, but that > > > (understandably) didn't seem to gain any traction. > > > > > > Thanks for any insights! > > > > > > Thanks, > > > Danny Kaehn > > > > > > > > One example is network cards which provide an mdio bus > > > > > bind through the child "mdio". One example of a specifically a > > > > > child i2c controller being bound to "i2c" can be found in > > > > > pine64,pinephone-keyboard.yaml. > > > > > But it's certainly possible this isn't the desired direction > moving forward > > > > > in DT -- my opinion should definitely be taken with a grain of > salt. Maybe > > > > > this is something I should follow up on with DT folks on that > DT vs. ACPI > > > > > thread made earlier. > > > > > > > > > > One thing I did notice when looking at the mfd subsystem is > that most DT > > > > > drivers actually match on the compatible string of the child > nodes, a.e. > > > > > "silabs,cp2112", "silabs,cp2112-gpio". "silabs,cp2112-i2c". We > could > > > > > implement that here, but I think that would make more sense if > we were to > > > > > actually split the cp2112 into mfd & platform drivers, and > additionally split > > > > > the DT binding by function. > > > > > > > > IIRC (but might be very well mistaken) the compatible strings for > children > > > > are discouraged. > > >
diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c index 27cadadda7c9..9e327763fd90 100644 --- a/drivers/hid/hid-cp2112.c +++ b/drivers/hid/hid-cp2112.c @@ -1234,6 +1234,10 @@ static int cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id) u8 buf[3]; struct cp2112_smbus_config_report config; struct gpio_irq_chip *girq; + struct i2c_timings timings; + struct fwnode_handle *child; + u32 addr; + const char *name; int ret; dev = devm_kzalloc(&hdev->dev, sizeof(*dev), GFP_KERNEL); @@ -1247,6 +1251,17 @@ static int cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id) mutex_init(&dev->lock); + device_for_each_child_node(&hdev->dev, child) { + name = fwnode_get_name(child); + ret = acpi_get_local_address(ACPI_HANDLE_FWNODE(child), &addr); + + if ((name && strcmp("i2c", name) == 0) || (!ret && addr == 0)) + device_set_node(&dev->adap.dev, child); + else if ((name && strcmp("gpio", name)) == 0 || + (!ret && addr == 1)) + dev->gc.fwnode = child; + } + ret = hid_parse(hdev); if (ret) { hid_err(hdev, "parse failed\n"); @@ -1292,6 +1307,9 @@ static int cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id) goto err_power_normal; } + i2c_parse_fw_timings(&dev->adap.dev, &timings, true); + + config.clock_speed = cpu_to_be32(timings.bus_freq_hz); config.retry_time = cpu_to_be16(1); ret = cp2112_hid_output(hdev, (u8 *)&config, sizeof(config),
Support describing the CP2112's I2C and GPIO interfaces in firmware. I2C and GPIO child nodes can either be children with names "i2c" and "gpio", or, for ACPI, device nodes with _ADR Zero and One, respectively. Additionally, support configuring the I2C bus speed from the clock-frequency device property. Signed-off-by: Danny Kaehn <kaehndan@gmail.com> --- drivers/hid/hid-cp2112.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)