Message ID | 1393342067-9086-1-git-send-email-shc_work@mail.ru |
---|---|
State | Superseded |
Headers | show |
On Tuesday 25 February 2014 19:27:47 Alexander Shiyan wrote: > Add a new driver for the ARM CLPS711X Pulse Width Modulator (PWM) interface. > This CPU contain two 4-bit PWM outputs with constant period, based on CPU > PLL frequency. PWM polarity is determined by hardware by power on reset. > > Signed-off-by: Alexander Shiyan <shc_work@mail.ru> Looks good, just one comment > +++ b/Documentation/devicetree/bindings/pwm/cirrus-clps711x-pwm.txt > @@ -0,0 +1,15 @@ > +* Cirris Logic CLPS711X PWM controller > + > +Required properties: > +- compatible: Should be "cirrus,clps711x-pwm". > +- reg: Physical base address and length of the controller's registers. > +- clocks: phandle to the PWM reference clock. > +- #pwm-cells: Should be 1. The cell specifies the index of the channel. > + > +Example: > + pwm: pwm@80000400 { > + compatible = "cirrus,clps711x-pwm"; > + reg = <0x80000400 0x4>; > + clocks = <&clks 8>; > + #pwm-cells = <1>; > + }; We really want to avoid wildcards in compatible strings. Can you call this "cirrus,cs89712-pwm" to match the first SoC that came with this hardware? Obviously if there was some chip before that (I'm not familiar with the model numbers), use that instead. You can either list all chips you know that have this in the driver, or you use "cirrus,cs89712-pwm" as the fallback, and use the name of the SoC you have as the more specific string. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-pwm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Вторник, 25 февраля 2014, 16:33 +01:00 от Arnd Bergmann <arnd@arndb.de>: > On Tuesday 25 February 2014 19:27:47 Alexander Shiyan wrote: > > Add a new driver for the ARM CLPS711X Pulse Width Modulator (PWM) interface. > > This CPU contain two 4-bit PWM outputs with constant period, based on CPU > > PLL frequency. PWM polarity is determined by hardware by power on reset. > > > > Signed-off-by: Alexander Shiyan <shc_work@mail.ru> > > Looks good, just one comment > > > +++ b/Documentation/devicetree/bindings/pwm/cirrus-clps711x-pwm.txt > > @@ -0,0 +1,15 @@ > > +* Cirris Logic CLPS711X PWM controller > > + > > +Required properties: > > +- compatible: Should be "cirrus,clps711x-pwm". > > +- reg: Physical base address and length of the controller's registers. > > +- clocks: phandle to the PWM reference clock. > > +- #pwm-cells: Should be 1. The cell specifies the index of the channel. > > + > > +Example: > > + pwm: pwm@80000400 { > > + compatible = "cirrus,clps711x-pwm"; > > + reg = <0x80000400 0x4>; > > + clocks = <&clks 8>; > > + #pwm-cells = <1>; > > + }; > > We really want to avoid wildcards in compatible strings. Can you call this > "cirrus,cs89712-pwm" to match the first SoC that came with this hardware? > Obviously if there was some chip before that (I'm not familiar with the > model numbers), use that instead. > > You can either list all chips you know that have this in the driver, > or you use "cirrus,cs89712-pwm" as the fallback, and use the name of > the SoC you have as the more specific string. It seems that in this case we will need to modify the compatibility string for other drivers that are already available in the kernel... ---
On Tuesday 25 February 2014 19:47:57 Alexander Shiyan wrote: > Вторник, 25 февраля 2014, 16:33 +01:00 от Arnd Bergmann <arnd@arndb.de>: > > On Tuesday 25 February 2014 19:27:47 Alexander Shiyan wrote: => > > > We really want to avoid wildcards in compatible strings. Can you call this > > "cirrus,cs89712-pwm" to match the first SoC that came with this hardware? > > Obviously if there was some chip before that (I'm not familiar with the > > model numbers), use that instead. > > > > You can either list all chips you know that have this in the driver, > > or you use "cirrus,cs89712-pwm" as the fallback, and use the name of > > the SoC you have as the more specific string. > > It seems that in this case we will need to modify the compatibility string > for other drivers that are already available in the kernel... Ah, right. I missed the binding for gpio and serial going in. DT maintainers, any suggestion on how we should proceed here? AFAICT, clps711x platform support is still work-in-progress, so we don't have any upstream users to worry about yet, but changing them is still going to be slightly messy. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-pwm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Feb 25, 2014 at 03:50:32PM +0000, Arnd Bergmann wrote: > On Tuesday 25 February 2014 19:47:57 Alexander Shiyan wrote: > > Вторник, 25 февраля 2014, 16:33 +01:00 от Arnd Bergmann <arnd@arndb.de>: > > > On Tuesday 25 February 2014 19:27:47 Alexander Shiyan wrote: > => > > > > We really want to avoid wildcards in compatible strings. Can you call this > > > "cirrus,cs89712-pwm" to match the first SoC that came with this hardware? > > > Obviously if there was some chip before that (I'm not familiar with the > > > model numbers), use that instead. > > > > > > You can either list all chips you know that have this in the driver, > > > or you use "cirrus,cs89712-pwm" as the fallback, and use the name of > > > the SoC you have as the more specific string. > > > > It seems that in this case we will need to modify the compatibility string > > for other drivers that are already available in the kernel... > > Ah, right. I missed the binding for gpio and serial going in. > > DT maintainers, any suggestion on how we should proceed here? > > AFAICT, clps711x platform support is still work-in-progress, so we don't > have any upstream users to worry about yet, but changing them is still > going to be slightly messy. When allocating any new compatible strings, as Arnd says, we should avoid wildcards as they're usually far too encompassing and end up causing more trouble than they're worth. In this case how problematic are the wildcard strings? I assume we still have specific strings earlier in any compatible list in any case? If not, and there are possible differences, that should be fixed right away. We have a few options: a) Update the docs only. Note in the docs that "cirrus,clps711x-$UNIT" means anything compatible with the $UNIT in the cs89712. This may be counter-intuitive, and if a new clps711x platform comes out with an incompatible $UNIT it should omit "cirrus,clps711x-$UNIT" from its compatible list, but otherwise no harm done. b) Deprecate the existing string. Add "cirrus,cs89712-$UNIT" to the binding docs and driver. Mark "cirrus,clps711x-$UNIT" as deprecated in the binding document. Replace "cirrus,clps711x-$UNIT" with "cirrus,cs89712-$UNIT" in all DTs. This will mean new DTBs won't work with an older kernel, but as support is a work in progress that might not matter. Old DTBs will continue to function. Iff you can guarantee that the old string is not possibly being used by anyone, it can be dropped from the driver. If not it has to remain (though can be commented to be deprecated), so that old DTBs function. It's probably best to leave it there. c) Deprecate, maintaining (forwards) compatibility. As above, but rather than replacing "cirrus,clps711x-$UNIT" with "cirrus,cs89712-$UNIT" in DTs, place "cirrus,cs89712-$UNIT" before "cirrus,clps711x-$UNIT" in DTs. This allows new DTBs to work with older kernels too. Depending on what level of support you have in mainline currently this may or may not be an important consideration. Cheers, Mark. -- To unsubscribe from this list: send the line "unsubscribe linux-pwm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hello. Среда, 26 февраля 2014, 16:00 UTC от Mark Rutland <mark.rutland@arm.com>: > On Tue, Feb 25, 2014 at 03:50:32PM +0000, Arnd Bergmann wrote: > > On Tuesday 25 February 2014 19:47:57 Alexander Shiyan wrote: > > > Вторник, 25 февраля 2014, 16:33 +01:00 от Arnd Bergmann <arnd@arndb.de>: > > > > On Tuesday 25 February 2014 19:27:47 Alexander Shiyan wrote: > > => > > > > > We really want to avoid wildcards in compatible strings. Can you call this > > > > "cirrus,cs89712-pwm" to match the first SoC that came with this hardware? > > > > Obviously if there was some chip before that (I'm not familiar with the > > > > model numbers), use that instead. > > > > > > > > You can either list all chips you know that have this in the driver, > > > > or you use "cirrus,cs89712-pwm" as the fallback, and use the name of > > > > the SoC you have as the more specific string. > > > > > > It seems that in this case we will need to modify the compatibility string > > > for other drivers that are already available in the kernel... > > > > Ah, right. I missed the binding for gpio and serial going in. > > > > DT maintainers, any suggestion on how we should proceed here? > > > > AFAICT, clps711x platform support is still work-in-progress, so we don't > > have any upstream users to worry about yet, but changing them is still > > going to be slightly messy. > > When allocating any new compatible strings, as Arnd says, we should > avoid wildcards as they're usually far too encompassing and end up > causing more trouble than they're worth. > > In this case how problematic are the wildcard strings? > > I assume we still have specific strings earlier in any compatible list > in any case? If not, and there are possible differences, that should be > fixed right away. > > We have a few options: > > a) Update the docs only. > > Note in the docs that "cirrus,clps711x-$UNIT" means anything > compatible with the $UNIT in the cs89712. This may be > counter-intuitive, and if a new clps711x platform comes out with an > incompatible $UNIT it should omit "cirrus,clps711x-$UNIT" from its > compatible list, but otherwise no harm done. > > b) Deprecate the existing string. > > Add "cirrus,cs89712-$UNIT" to the binding docs and driver. Mark > "cirrus,clps711x-$UNIT" as deprecated in the binding document. > Replace "cirrus,clps711x-$UNIT" with "cirrus,cs89712-$UNIT" in all > DTs. > > This will mean new DTBs won't work with an older kernel, but as > support is a work in progress that might not matter. Old DTBs will > continue to function. > > Iff you can guarantee that the old string is not possibly being used > by anyone, it can be dropped from the driver. If not it has to remain > (though can be commented to be deprecated), so that old DTBs > function. It's probably best to leave it there. > > c) Deprecate, maintaining (forwards) compatibility. > > As above, but rather than replacing "cirrus,clps711x-$UNIT" with > "cirrus,cs89712-$UNIT" in DTs, place "cirrus,cs89712-$UNIT" before > "cirrus,clps711x-$UNIT" in DTs. This allows new DTBs to work with > older kernels too. Depending on what level of support you have in > mainline currently this may or may not be an important consideration. If I understood correctly, in the variant "a", we change nothing. Ie compatibility string is a global to entire platform, and in case of any CPU differences, we simply add the additional compatibility string fully meets the CPU name, for example for Cirrus Logic EP7312 this will be like: "cirrus,ep7312-hw", "cirrus,clps711x-hw". Correct? Thanks. ---
On Wed, Feb 26, 2014 at 04:50:46PM +0000, Alexander Shiyan wrote: > Hello. > > Среда, 26 февраля 2014, 16:00 UTC от Mark Rutland <mark.rutland@arm.com>: > > On Tue, Feb 25, 2014 at 03:50:32PM +0000, Arnd Bergmann wrote: > > > On Tuesday 25 February 2014 19:47:57 Alexander Shiyan wrote: > > > > Вторник, 25 февраля 2014, 16:33 +01:00 от Arnd Bergmann <arnd@arndb.de>: > > > > > On Tuesday 25 February 2014 19:27:47 Alexander Shiyan wrote: > > > => > > > > > > We really want to avoid wildcards in compatible strings. Can you call this > > > > > "cirrus,cs89712-pwm" to match the first SoC that came with this hardware? > > > > > Obviously if there was some chip before that (I'm not familiar with the > > > > > model numbers), use that instead. > > > > > > > > > > You can either list all chips you know that have this in the driver, > > > > > or you use "cirrus,cs89712-pwm" as the fallback, and use the name of > > > > > the SoC you have as the more specific string. > > > > > > > > It seems that in this case we will need to modify the compatibility string > > > > for other drivers that are already available in the kernel... > > > > > > Ah, right. I missed the binding for gpio and serial going in. > > > > > > DT maintainers, any suggestion on how we should proceed here? > > > > > > AFAICT, clps711x platform support is still work-in-progress, so we don't > > > have any upstream users to worry about yet, but changing them is still > > > going to be slightly messy. > > > > When allocating any new compatible strings, as Arnd says, we should > > avoid wildcards as they're usually far too encompassing and end up > > causing more trouble than they're worth. > > > > In this case how problematic are the wildcard strings? > > > > I assume we still have specific strings earlier in any compatible list > > in any case? If not, and there are possible differences, that should be > > fixed right away. > > > > We have a few options: > > > > a) Update the docs only. > > > > Note in the docs that "cirrus,clps711x-$UNIT" means anything > > compatible with the $UNIT in the cs89712. This may be > > counter-intuitive, and if a new clps711x platform comes out with an > > incompatible $UNIT it should omit "cirrus,clps711x-$UNIT" from its > > compatible list, but otherwise no harm done. > > > > b) Deprecate the existing string. > > > > Add "cirrus,cs89712-$UNIT" to the binding docs and driver. Mark > > "cirrus,clps711x-$UNIT" as deprecated in the binding document. > > Replace "cirrus,clps711x-$UNIT" with "cirrus,cs89712-$UNIT" in all > > DTs. > > > > This will mean new DTBs won't work with an older kernel, but as > > support is a work in progress that might not matter. Old DTBs will > > continue to function. > > > > Iff you can guarantee that the old string is not possibly being used > > by anyone, it can be dropped from the driver. If not it has to remain > > (though can be commented to be deprecated), so that old DTBs > > function. It's probably best to leave it there. > > > > c) Deprecate, maintaining (forwards) compatibility. > > > > As above, but rather than replacing "cirrus,clps711x-$UNIT" with > > "cirrus,cs89712-$UNIT" in DTs, place "cirrus,cs89712-$UNIT" before > > "cirrus,clps711x-$UNIT" in DTs. This allows new DTBs to work with > > older kernels too. Depending on what level of support you have in > > mainline currently this may or may not be an important consideration. > > If I understood correctly, in the variant "a", we change nothing. > Ie compatibility string is a global to entire platform, and in case of any > CPU differences, we simply add the additional compatibility string fully > meets the CPU name, for example for Cirrus Logic EP7312 this will be > like: "cirrus,ep7312-hw", "cirrus,clps711x-hw". > Correct? That depends. Option a still requires that we give a definite meaning to "cirrus,clps711x-$UNIT" to mean compatible with the unit on the cs89712. If a new unit is compatible with this, then it can have "cirrus,clps711x-$UNIT" as a fallback in its compatible list. If a new unit is not compatible and must be handled differently, then it should not have "cirrus,clps711x-$UNIT" in its compatible list. The naming you suggest for "cirrus,ep7312-$UNIT" seems sensible in either case. Cheers, Mark. -- To unsubscribe from this list: send the line "unsubscribe linux-pwm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, 26 Feb 2014 16:00:46 +0000 Mark Rutland <mark.rutland@arm.com> wrote: > On Tue, Feb 25, 2014 at 03:50:32PM +0000, Arnd Bergmann wrote: > > On Tuesday 25 February 2014 19:47:57 Alexander Shiyan wrote: > > > Вторник, 25 февраля 2014, 16:33 +01:00 от Arnd Bergmann <arnd@arndb.de>: > > > > On Tuesday 25 February 2014 19:27:47 Alexander Shiyan wrote: > > => > > > > > We really want to avoid wildcards in compatible strings. Can you call this > > > > "cirrus,cs89712-pwm" to match the first SoC that came with this hardware? > > > > Obviously if there was some chip before that (I'm not familiar with the > > > > model numbers), use that instead. > > > > > > > > You can either list all chips you know that have this in the driver, > > > > or you use "cirrus,cs89712-pwm" as the fallback, and use the name of > > > > the SoC you have as the more specific string. > > > > > > It seems that in this case we will need to modify the compatibility string > > > for other drivers that are already available in the kernel... > > > > Ah, right. I missed the binding for gpio and serial going in. > > > > DT maintainers, any suggestion on how we should proceed here? > > > > AFAICT, clps711x platform support is still work-in-progress, so we don't > > have any upstream users to worry about yet, but changing them is still > > going to be slightly messy. > > When allocating any new compatible strings, as Arnd says, we should > avoid wildcards as they're usually far too encompassing and end up > causing more trouble than they're worth. > > In this case how problematic are the wildcard strings? > > I assume we still have specific strings earlier in any compatible list > in any case? If not, and there are possible differences, that should be > fixed right away. > > We have a few options: > > a) Update the docs only. > > Note in the docs that "cirrus,clps711x-$UNIT" means anything > compatible with the $UNIT in the cs89712. This may be > counter-intuitive, and if a new clps711x platform comes out with an > incompatible $UNIT it should omit "cirrus,clps711x-$UNIT" from its > compatible list, but otherwise no harm done. > > b) Deprecate the existing string. > > Add "cirrus,cs89712-$UNIT" to the binding docs and driver. Mark > "cirrus,clps711x-$UNIT" as deprecated in the binding document. > Replace "cirrus,clps711x-$UNIT" with "cirrus,cs89712-$UNIT" in all > DTs. > > This will mean new DTBs won't work with an older kernel, but as > support is a work in progress that might not matter. Old DTBs will > continue to function. > > Iff you can guarantee that the old string is not possibly being used > by anyone, it can be dropped from the driver. If not it has to remain > (though can be commented to be deprecated), so that old DTBs > function. It's probably best to leave it there. > > c) Deprecate, maintaining (forwards) compatibility. > > As above, but rather than replacing "cirrus,clps711x-$UNIT" with > "cirrus,cs89712-$UNIT" in DTs, place "cirrus,cs89712-$UNIT" before > "cirrus,clps711x-$UNIT" in DTs. This allows new DTBs to work with > older kernels too. Depending on what level of support you have in > mainline currently this may or may not be an important consideration. Hello. I want to elaborate on the current CLPS711X lineup: PS7110 - EOL October 30, 2001 PS7111 - EOL October 30, 2001 EP7209 - EOL April 25, 2003 EP7211 - EOL April 25, 2003 EP7212 - EOL April 25, 2003 CS89712 - EOL August 15, 2005 EP7309 - Production EP7311 - Production EP7312 - Production So at the moment, and long enough, produced only three models of CPUs. I am sure that the hardware with old CPUs will not be able to use the new kernel due to memory limitations, low CPU frequency, etc. My suggestion is to always use a compatibility string for platform entirely, ie "cirrus,clps711x-$UNIT", otherwise it may result in misleading. In any case, I would like to hear the final decision on this issue, since there are several drivers already using this scheme and some drivers awaiting applying into the kernel. I do not insist on its position, but just want to clarify to make changes to existing drivers and use the approved compatibility string in the future. At the current stage, these changes will not lead to anything terrible. Thanks.
On Saturday 01 March 2014, Alexander Shiyan wrote: > I want to elaborate on the current CLPS711X lineup: > PS7110 - EOL October 30, 2001 > PS7111 - EOL October 30, 2001 > EP7209 - EOL April 25, 2003 > EP7211 - EOL April 25, 2003 > EP7212 - EOL April 25, 2003 > CS89712 - EOL August 15, 2005 > EP7309 - Production > EP7311 - Production > EP7312 - Production Thanks for the list. I wonder if there is a good place to keep this in the kernel source for reference. > So at the moment, and long enough, produced only three models of CPUs. > I am sure that the hardware with old CPUs will not be able to use the > new kernel due to memory limitations, low CPU frequency, etc. > > My suggestion is to always use a compatibility string for platform entirely, > ie "cirrus,clps711x-$UNIT", otherwise it may result in misleading. From your list, it's pretty clear that there won't be any new chips named PS711x for x > 1, so using that string is not ambiguous. That is good to know. It's also the oldest chip in the family, so naming things after that is consistent. > In any case, I would like to hear the final decision on this issue, > since there are several drivers already using this scheme and some drivers > awaiting applying into the kernel. > I do not insist on its position, but just want to clarify to make changes > to existing drivers and use the approved compatibility string in the future. > At the current stage, these changes will not lead to anything terrible. How about we keep using the cirrus,clps711x as the string that drivers match against, but change the DT representation to always list the specific model in addition? That way we are prepared to handle quirks if we need to, but you don't have to change the binding in incompatible ways. This means you should list e.g. compatible = "cirrus,ep7309-pwm", "cirrus,clps711x-pwm"; or compatible = "cirrus,clps7110-pwm", "cirrus,clps711x-pwm"; depending on the model. For units that were introduced in a later model, I would recommend to use the first model that had it rather than the original clps711x that didn't, like compatible = "cirrus,ep7311-kitchensink", "cirrus-ep7211-kitchensink"; For bindings that are already reviewed and merged, I wouldn't change them any more even if they inaccurately list clps711x for units that were not present in clps7111, but for new ones I'd prefer to follow the common practice to your best knowledge. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-pwm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Суббота, 1 марта 2014, 12:40 +01:00 от Arnd Bergmann <arnd@arndb.de>: > On Saturday 01 March 2014, Alexander Shiyan wrote: > > I want to elaborate on the current CLPS711X lineup: > > PS7110 - EOL October 30, 2001 > > PS7111 - EOL October 30, 2001 > > EP7209 - EOL April 25, 2003 > > EP7211 - EOL April 25, 2003 > > EP7212 - EOL April 25, 2003 > > CS89712 - EOL August 15, 2005 > > EP7309 - Production > > EP7311 - Production > > EP7312 - Production > > Thanks for the list. I wonder if there is a good place to keep this in the > kernel source for reference. > > > So at the moment, and long enough, produced only three models of CPUs. > > I am sure that the hardware with old CPUs will not be able to use the > > new kernel due to memory limitations, low CPU frequency, etc. > > > > My suggestion is to always use a compatibility string for platform entirely, > > ie "cirrus,clps711x-$UNIT", otherwise it may result in misleading. > > From your list, it's pretty clear that there won't be any new chips named > PS711x for x > 1, so using that string is not ambiguous. That is good > to know. It's also the oldest chip in the family, so naming things after that > is consistent. > > > In any case, I would like to hear the final decision on this issue, > > since there are several drivers already using this scheme and some drivers > > awaiting applying into the kernel. > > I do not insist on its position, but just want to clarify to make changes > > to existing drivers and use the approved compatibility string in the future. > > At the current stage, these changes will not lead to anything terrible. > > How about we keep using the cirrus,clps711x as the string that drivers > match against, but change the DT representation to always list the specific > model in addition? That way we are prepared to handle quirks if we need to, > but you don't have to change the binding in incompatible ways. > > This means you should list e.g. > > compatible = "cirrus,ep7309-pwm", "cirrus,clps711x-pwm"; > > or > > compatible = "cirrus,clps7110-pwm", "cirrus,clps711x-pwm"; > > depending on the model. For units that were introduced in a later > model, I would recommend to use the first model that had it rather > than the original clps711x that didn't, like > > compatible = "cirrus,ep7311-kitchensink", "cirrus-ep7211-kitchensink"; > > For bindings that are already reviewed and merged, I wouldn't change > them any more even if they inaccurately list clps711x for units that > were not present in clps7111, but for new ones I'd prefer to follow > the common practice to your best knowledge. Excellent, let's do so. I will prepare a patch that will change compatibility strings for examples in the current bindings documents. For this driver (PWM), I just send a third version. ---
diff --git a/Documentation/devicetree/bindings/pwm/cirrus-clps711x-pwm.txt b/Documentation/devicetree/bindings/pwm/cirrus-clps711x-pwm.txt new file mode 100644 index 0000000..e252f6d --- /dev/null +++ b/Documentation/devicetree/bindings/pwm/cirrus-clps711x-pwm.txt @@ -0,0 +1,15 @@ +* Cirris Logic CLPS711X PWM controller + +Required properties: +- compatible: Should be "cirrus,clps711x-pwm". +- reg: Physical base address and length of the controller's registers. +- clocks: phandle to the PWM reference clock. +- #pwm-cells: Should be 1. The cell specifies the index of the channel. + +Example: + pwm: pwm@80000400 { + compatible = "cirrus,clps711x-pwm"; + reg = <0x80000400 0x4>; + clocks = <&clks 8>; + #pwm-cells = <1>; + }; diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index 22f2f28..d3a2c26 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -71,6 +71,15 @@ config PWM_BFIN To compile this driver as a module, choose M here: the module will be called pwm-bfin. +config PWM_CLPS711X + tristate "CLPS711X PWM support" + depends on ARCH_CLPS711X || COMPILE_TEST + help + Generic PWM framework driver for Cirrus Logic CLPS711X. + + To compile this driver as a module, choose M here: the module + will be called pwm-clps711x. + config PWM_EP93XX tristate "Cirrus Logic EP93xx PWM support" depends on ARCH_EP93XX diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index d8906ec..d676681 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -4,6 +4,7 @@ obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o obj-$(CONFIG_PWM_ATMEL_TCB) += pwm-atmel-tcb.o obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o +obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o obj-$(CONFIG_PWM_IMX) += pwm-imx.o obj-$(CONFIG_PWM_JZ4740) += pwm-jz4740.o diff --git a/drivers/pwm/pwm-clps711x.c b/drivers/pwm/pwm-clps711x.c new file mode 100644 index 0000000..fafb6a0 --- /dev/null +++ b/drivers/pwm/pwm-clps711x.c @@ -0,0 +1,176 @@ +/* + * Cirrus Logic CLPS711X PWM driver + * + * Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/pwm.h> + +struct clps711x_chip { + struct pwm_chip chip; + void __iomem *pmpcon; + struct clk *clk; + spinlock_t lock; +}; + +static inline struct clps711x_chip *to_clps711x_chip(struct pwm_chip *chip) +{ + return container_of(chip, struct clps711x_chip, chip); +} + +static void clps711x_pwm_update_val(struct clps711x_chip *priv, u32 n, u32 v) +{ + /* PWM0 - bits 4..7, PWM1 - bits 8..11 */ + u32 shift = (n + 1) * 4; + unsigned long flags; + u32 tmp; + + spin_lock_irqsave(&priv->lock, flags); + + tmp = readl(priv->pmpcon); + tmp &= ~(0xf << shift); + tmp |= v << shift; + writel(tmp, priv->pmpcon); + + spin_unlock_irqrestore(&priv->lock, flags); +} + +static unsigned int clps711x_get_duty(struct pwm_device *pwm, unsigned int v) +{ + /* Duty cycle 0..15 max */ + return DIV_ROUND_CLOSEST(v * 0xf, pwm_get_period(pwm)); +} + +static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct clps711x_chip *priv = to_clps711x_chip(chip); + unsigned int freq = clk_get_rate(priv->clk); + + if (!freq) + return -EINVAL; + + /* Store constant period value */ + pwm_set_period(pwm, DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq)); + + return 0; +} + +static int clps711x_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, + int duty_ns, int period_ns) +{ + struct clps711x_chip *priv = to_clps711x_chip(chip); + unsigned int duty; + + if (period_ns != pwm_get_period(pwm)) + return -EINVAL; + + duty = clps711x_get_duty(pwm, duty_ns); + clps711x_pwm_update_val(priv, pwm->hwpwm, duty); + + return 0; +} + +static int clps711x_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct clps711x_chip *priv = to_clps711x_chip(chip); + unsigned int duty; + + duty = clps711x_get_duty(pwm, pwm_get_duty_cycle(pwm)); + clps711x_pwm_update_val(priv, pwm->hwpwm, duty); + + return 0; +} + +static void clps711x_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct clps711x_chip *priv = to_clps711x_chip(chip); + + clps711x_pwm_update_val(priv, pwm->hwpwm, 0); +} + +static const struct pwm_ops clps711x_pwm_ops = { + .request = clps711x_pwm_request, + .config = clps711x_pwm_config, + .enable = clps711x_pwm_enable, + .disable = clps711x_pwm_disable, + .owner = THIS_MODULE, +}; + +static struct pwm_device *clps711x_pwm_xlate(struct pwm_chip *chip, + const struct of_phandle_args *args) +{ + if (args->args[0] >= chip->npwm) + return ERR_PTR(-EINVAL); + + return pwm_request_from_chip(chip, args->args[0], NULL); +} + +static int clps711x_pwm_probe(struct platform_device *pdev) +{ + struct clps711x_chip *priv; + struct resource *res; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + priv->pmpcon = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(priv->pmpcon)) + return PTR_ERR(priv->pmpcon); + + priv->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(priv->clk)) + return PTR_ERR(priv->clk); + + priv->chip.ops = &clps711x_pwm_ops; + priv->chip.dev = &pdev->dev; + priv->chip.base = -1; + priv->chip.npwm = 2; + priv->chip.of_xlate = clps711x_pwm_xlate; + priv->chip.of_pwm_n_cells = 1; + + spin_lock_init(&priv->lock); + + platform_set_drvdata(pdev, priv); + + return pwmchip_add(&priv->chip); +} + +static int clps711x_pwm_remove(struct platform_device *pdev) +{ + struct clps711x_chip *priv = platform_get_drvdata(pdev); + + return pwmchip_remove(&priv->chip); +} + +static const struct of_device_id __maybe_unused clps711x_pwm_dt_ids[] = { + { .compatible = "cirrus,clps711x-pwm", }, + { } +}; +MODULE_DEVICE_TABLE(of, clps711x_pwm_dt_ids); + +static struct platform_driver clps711x_pwm_driver = { + .driver = { + .name = "clps711x-pwm", + .owner = THIS_MODULE, + .of_match_table = of_match_ptr(clps711x_pwm_dt_ids), + }, + .probe = clps711x_pwm_probe, + .remove = clps711x_pwm_remove, +}; +module_platform_driver(clps711x_pwm_driver); + +MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>"); +MODULE_DESCRIPTION("Cirrus Logic CLPS711X PWM driver"); +MODULE_LICENSE("GPL");
Add a new driver for the ARM CLPS711X Pulse Width Modulator (PWM) interface. This CPU contain two 4-bit PWM outputs with constant period, based on CPU PLL frequency. PWM polarity is determined by hardware by power on reset. Signed-off-by: Alexander Shiyan <shc_work@mail.ru> --- .../bindings/pwm/cirrus-clps711x-pwm.txt | 15 ++ drivers/pwm/Kconfig | 9 ++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-clps711x.c | 176 +++++++++++++++++++++ 4 files changed, 201 insertions(+) create mode 100644 Documentation/devicetree/bindings/pwm/cirrus-clps711x-pwm.txt create mode 100644 drivers/pwm/pwm-clps711x.c