Re: [Intel-gfx] [PATCH 6/8] drivers/pwm: Add Crystalcove (CRC) PWM driver
On Sat, Jun 20, 2015 at 11:34 PM, Paul Gortmaker wrote: > [Re: [Intel-gfx] [PATCH 6/8] drivers/pwm: Add Crystalcove (CRC) PWM driver] > On 20/06/2015 (Sat 13:23) Paul Bolle wrote: > >> [Added Paul Gortmaker.] >> >> Hi Shobhit, >> >> On Fri, 2015-06-19 at 12:16 +0530, Shobhit Kumar wrote: >> > So what is the exact big problem with this ? >> >> The main problem I have is that it's hard to read a submitter's mind. >> And, I think, in cases like this we need to know if the submitter just >> made some silly mistake or that the mismatch (between Kconfig type and >> code) was intentional. So each time such a mismatch is spotted the >> submitter ought to be asked about it. >> >> (I'd guess that one or two new drivers are submitted _each_ day. And >> these mismatches are quite common. I'd say I receive answers like: >> - "Oops, yes bool should have been tristate"; or >> - "Oops, forgot to clean up after noticing tristate didn't work"; or >> - "I just copy-and-pasted a similar driver, the module stuff isn't >> actually needed" >> at least once a week. Not sure, I don't keep track of this stuff.) >> >> Furthermore, it appears that Paul Gortmaker is on a mission to, badly >> summarized, untangle the module and init code. See for instance >> https://lkml.org/lkml/2015/5/28/809 and >> https://lkml.org/lkml/2015/5/31/205 . >> >> Now, I don't know whether (other) Paul is bothered by these MODULE_* >> macros. But Paul did submit a series that adds > > Yes, I agree that it would be nice to not see these mismatches, > regardless of whether we can get away with it or not. > >> builtin_platform_driver(), see https://lkml.org/lkml/2015/5/10/131 . >> That new macro ensures built-in only code doesn't have to use >> module_platform_driver(), which your patch also uses. So perhaps Paul >> can explain some of the non-obvious issues caused by built-in only code >> using module specific constructs. > > In https://lkml.org/lkml/2015/5/10/125 I'd written: > > There are several downsides to this: > 1) The code can appear modular to a reader of the code, and they > won't know if the code really is modular without checking the > Makefile and Kconfig to see if compilation is governed by a > bool or tristate. > 2) Coders of drivers may be tempted to code up an __exit function > that is never used, just in order to satisfy the required three > args of the modular registration function. > 3) Non-modular code ends up including the which increases > CPP overhead that they don't need. > 4) It hinders us from performing better separation of the module > init code and the generic init code. > Okay. Get the idea and the need in terms of clear separation. Its just that there are quite a few built-in drivers using module initialization that I assumed its okay. > The nature of linux means that thousands of developers are reading the > code every day -- so I think that there is a genuine value in having the > code convey a clear message on how it was designed to be used. Only > using module related headers/macros for genuinely modular code helps us > (albeit in a small way) towards achieving that. > > Looking at this thread, I see that one of the reasons given for this > code's ambiguous module vs. built-in identity was the observation of a > similar identity crisis of the related INTEL_SOC_PMIC code. Does that > not back up the point above about the value in having the code speak for > itself? So IMHO we probably should clarify the PMIC code vs. adding > another example that looks just like it. > Okay agree. I think there are quite of them lurking in the sources which would need correction. For this PWM driver I will take care as suggested. Regards Shobhit > Paul. > -- > >> >> > I can anyway shove out these macros to end the discussion. >> >> I'd rather convince you than annoy you into doing as I suggested. >> >> > BTW whether you buy the argument or not, please do treat yourself >> > with ice cream for being able to make such a comment. >> >> Will do. >> >> Thanks, >> >> >> Paul Bolle >> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/
Re: [Intel-gfx] [PATCH 6/8] drivers/pwm: Add Crystalcove (CRC) PWM driver
On Sat, Jun 20, 2015 at 11:34 PM, Paul Gortmaker paul.gortma...@windriver.com wrote: [Re: [Intel-gfx] [PATCH 6/8] drivers/pwm: Add Crystalcove (CRC) PWM driver] On 20/06/2015 (Sat 13:23) Paul Bolle wrote: [Added Paul Gortmaker.] Hi Shobhit, On Fri, 2015-06-19 at 12:16 +0530, Shobhit Kumar wrote: So what is the exact big problem with this ? The main problem I have is that it's hard to read a submitter's mind. And, I think, in cases like this we need to know if the submitter just made some silly mistake or that the mismatch (between Kconfig type and code) was intentional. So each time such a mismatch is spotted the submitter ought to be asked about it. (I'd guess that one or two new drivers are submitted _each_ day. And these mismatches are quite common. I'd say I receive answers like: - Oops, yes bool should have been tristate; or - Oops, forgot to clean up after noticing tristate didn't work; or - I just copy-and-pasted a similar driver, the module stuff isn't actually needed at least once a week. Not sure, I don't keep track of this stuff.) Furthermore, it appears that Paul Gortmaker is on a mission to, badly summarized, untangle the module and init code. See for instance https://lkml.org/lkml/2015/5/28/809 and https://lkml.org/lkml/2015/5/31/205 . Now, I don't know whether (other) Paul is bothered by these MODULE_* macros. But Paul did submit a series that adds Yes, I agree that it would be nice to not see these mismatches, regardless of whether we can get away with it or not. builtin_platform_driver(), see https://lkml.org/lkml/2015/5/10/131 . That new macro ensures built-in only code doesn't have to use module_platform_driver(), which your patch also uses. So perhaps Paul can explain some of the non-obvious issues caused by built-in only code using module specific constructs. In https://lkml.org/lkml/2015/5/10/125 I'd written: There are several downsides to this: 1) The code can appear modular to a reader of the code, and they won't know if the code really is modular without checking the Makefile and Kconfig to see if compilation is governed by a bool or tristate. 2) Coders of drivers may be tempted to code up an __exit function that is never used, just in order to satisfy the required three args of the modular registration function. 3) Non-modular code ends up including the module.h which increases CPP overhead that they don't need. 4) It hinders us from performing better separation of the module init code and the generic init code. Okay. Get the idea and the need in terms of clear separation. Its just that there are quite a few built-in drivers using module initialization that I assumed its okay. The nature of linux means that thousands of developers are reading the code every day -- so I think that there is a genuine value in having the code convey a clear message on how it was designed to be used. Only using module related headers/macros for genuinely modular code helps us (albeit in a small way) towards achieving that. Looking at this thread, I see that one of the reasons given for this code's ambiguous module vs. built-in identity was the observation of a similar identity crisis of the related INTEL_SOC_PMIC code. Does that not back up the point above about the value in having the code speak for itself? So IMHO we probably should clarify the PMIC code vs. adding another example that looks just like it. Okay agree. I think there are quite of them lurking in the sources which would need correction. For this PWM driver I will take care as suggested. Regards Shobhit Paul. -- I can anyway shove out these macros to end the discussion. I'd rather convince you than annoy you into doing as I suggested. BTW whether you buy the argument or not, please do treat yourself with ice cream for being able to make such a comment. Will do. Thanks, Paul Bolle -- To unsubscribe from this list: send the line unsubscribe linux-kernel in Please read the FAQ at http://www.tux.org/lkml/
Re: [Intel-gfx] [PATCH 6/8] drivers/pwm: Add Crystalcove (CRC) PWM driver
[Re: [Intel-gfx] [PATCH 6/8] drivers/pwm: Add Crystalcove (CRC) PWM driver] On 20/06/2015 (Sat 13:23) Paul Bolle wrote: > [Added Paul Gortmaker.] > > Hi Shobhit, > > On Fri, 2015-06-19 at 12:16 +0530, Shobhit Kumar wrote: > > So what is the exact big problem with this ? > > The main problem I have is that it's hard to read a submitter's mind. > And, I think, in cases like this we need to know if the submitter just > made some silly mistake or that the mismatch (between Kconfig type and > code) was intentional. So each time such a mismatch is spotted the > submitter ought to be asked about it. > > (I'd guess that one or two new drivers are submitted _each_ day. And > these mismatches are quite common. I'd say I receive answers like: > - "Oops, yes bool should have been tristate"; or > - "Oops, forgot to clean up after noticing tristate didn't work"; or > - "I just copy-and-pasted a similar driver, the module stuff isn't > actually needed" > at least once a week. Not sure, I don't keep track of this stuff.) > > Furthermore, it appears that Paul Gortmaker is on a mission to, badly > summarized, untangle the module and init code. See for instance > https://lkml.org/lkml/2015/5/28/809 and > https://lkml.org/lkml/2015/5/31/205 . > > Now, I don't know whether (other) Paul is bothered by these MODULE_* > macros. But Paul did submit a series that adds Yes, I agree that it would be nice to not see these mismatches, regardless of whether we can get away with it or not. > builtin_platform_driver(), see https://lkml.org/lkml/2015/5/10/131 . > That new macro ensures built-in only code doesn't have to use > module_platform_driver(), which your patch also uses. So perhaps Paul > can explain some of the non-obvious issues caused by built-in only code > using module specific constructs. In https://lkml.org/lkml/2015/5/10/125 I'd written: There are several downsides to this: 1) The code can appear modular to a reader of the code, and they won't know if the code really is modular without checking the Makefile and Kconfig to see if compilation is governed by a bool or tristate. 2) Coders of drivers may be tempted to code up an __exit function that is never used, just in order to satisfy the required three args of the modular registration function. 3) Non-modular code ends up including the which increases CPP overhead that they don't need. 4) It hinders us from performing better separation of the module init code and the generic init code. The nature of linux means that thousands of developers are reading the code every day -- so I think that there is a genuine value in having the code convey a clear message on how it was designed to be used. Only using module related headers/macros for genuinely modular code helps us (albeit in a small way) towards achieving that. Looking at this thread, I see that one of the reasons given for this code's ambiguous module vs. built-in identity was the observation of a similar identity crisis of the related INTEL_SOC_PMIC code. Does that not back up the point above about the value in having the code speak for itself? So IMHO we probably should clarify the PMIC code vs. adding another example that looks just like it. Paul. -- > > > I can anyway shove out these macros to end the discussion. > > I'd rather convince you than annoy you into doing as I suggested. > > > BTW whether you buy the argument or not, please do treat yourself > > with ice cream for being able to make such a comment. > > Will do. > > Thanks, > > > Paul Bolle > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/
Re: [Intel-gfx] [PATCH 6/8] drivers/pwm: Add Crystalcove (CRC) PWM driver
[Added Paul Gortmaker.] Hi Shobhit, On Fri, 2015-06-19 at 12:16 +0530, Shobhit Kumar wrote: > So what is the exact big problem with this ? The main problem I have is that it's hard to read a submitter's mind. And, I think, in cases like this we need to know if the submitter just made some silly mistake or that the mismatch (between Kconfig type and code) was intentional. So each time such a mismatch is spotted the submitter ought to be asked about it. (I'd guess that one or two new drivers are submitted _each_ day. And these mismatches are quite common. I'd say I receive answers like: - "Oops, yes bool should have been tristate"; or - "Oops, forgot to clean up after noticing tristate didn't work"; or - "I just copy-and-pasted a similar driver, the module stuff isn't actually needed" at least once a week. Not sure, I don't keep track of this stuff.) Furthermore, it appears that Paul Gortmaker is on a mission to, badly summarized, untangle the module and init code. See for instance https://lkml.org/lkml/2015/5/28/809 and https://lkml.org/lkml/2015/5/31/205 . Now, I don't know whether (other) Paul is bothered by these MODULE_* macros. But Paul did submit a series that adds builtin_platform_driver(), see https://lkml.org/lkml/2015/5/10/131 . That new macro ensures built-in only code doesn't have to use module_platform_driver(), which your patch also uses. So perhaps Paul can explain some of the non-obvious issues caused by built-in only code using module specific constructs. > I can anyway shove out these macros to end the discussion. I'd rather convince you than annoy you into doing as I suggested. > BTW whether you buy the argument or not, please do treat yourself > with ice cream for being able to make such a comment. Will do. Thanks, Paul Bolle -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/
Re: [Intel-gfx] [PATCH 6/8] drivers/pwm: Add Crystalcove (CRC) PWM driver
[Added Paul Gortmaker.] Hi Shobhit, On Fri, 2015-06-19 at 12:16 +0530, Shobhit Kumar wrote: So what is the exact big problem with this ? The main problem I have is that it's hard to read a submitter's mind. And, I think, in cases like this we need to know if the submitter just made some silly mistake or that the mismatch (between Kconfig type and code) was intentional. So each time such a mismatch is spotted the submitter ought to be asked about it. (I'd guess that one or two new drivers are submitted _each_ day. And these mismatches are quite common. I'd say I receive answers like: - Oops, yes bool should have been tristate; or - Oops, forgot to clean up after noticing tristate didn't work; or - I just copy-and-pasted a similar driver, the module stuff isn't actually needed at least once a week. Not sure, I don't keep track of this stuff.) Furthermore, it appears that Paul Gortmaker is on a mission to, badly summarized, untangle the module and init code. See for instance https://lkml.org/lkml/2015/5/28/809 and https://lkml.org/lkml/2015/5/31/205 . Now, I don't know whether (other) Paul is bothered by these MODULE_* macros. But Paul did submit a series that adds builtin_platform_driver(), see https://lkml.org/lkml/2015/5/10/131 . That new macro ensures built-in only code doesn't have to use module_platform_driver(), which your patch also uses. So perhaps Paul can explain some of the non-obvious issues caused by built-in only code using module specific constructs. I can anyway shove out these macros to end the discussion. I'd rather convince you than annoy you into doing as I suggested. BTW whether you buy the argument or not, please do treat yourself with ice cream for being able to make such a comment. Will do. Thanks, Paul Bolle -- To unsubscribe from this list: send the line unsubscribe linux-kernel in Please read the FAQ at http://www.tux.org/lkml/
Re: [Intel-gfx] [PATCH 6/8] drivers/pwm: Add Crystalcove (CRC) PWM driver
[Re: [Intel-gfx] [PATCH 6/8] drivers/pwm: Add Crystalcove (CRC) PWM driver] On 20/06/2015 (Sat 13:23) Paul Bolle wrote: [Added Paul Gortmaker.] Hi Shobhit, On Fri, 2015-06-19 at 12:16 +0530, Shobhit Kumar wrote: So what is the exact big problem with this ? The main problem I have is that it's hard to read a submitter's mind. And, I think, in cases like this we need to know if the submitter just made some silly mistake or that the mismatch (between Kconfig type and code) was intentional. So each time such a mismatch is spotted the submitter ought to be asked about it. (I'd guess that one or two new drivers are submitted _each_ day. And these mismatches are quite common. I'd say I receive answers like: - Oops, yes bool should have been tristate; or - Oops, forgot to clean up after noticing tristate didn't work; or - I just copy-and-pasted a similar driver, the module stuff isn't actually needed at least once a week. Not sure, I don't keep track of this stuff.) Furthermore, it appears that Paul Gortmaker is on a mission to, badly summarized, untangle the module and init code. See for instance https://lkml.org/lkml/2015/5/28/809 and https://lkml.org/lkml/2015/5/31/205 . Now, I don't know whether (other) Paul is bothered by these MODULE_* macros. But Paul did submit a series that adds Yes, I agree that it would be nice to not see these mismatches, regardless of whether we can get away with it or not. builtin_platform_driver(), see https://lkml.org/lkml/2015/5/10/131 . That new macro ensures built-in only code doesn't have to use module_platform_driver(), which your patch also uses. So perhaps Paul can explain some of the non-obvious issues caused by built-in only code using module specific constructs. In https://lkml.org/lkml/2015/5/10/125 I'd written: There are several downsides to this: 1) The code can appear modular to a reader of the code, and they won't know if the code really is modular without checking the Makefile and Kconfig to see if compilation is governed by a bool or tristate. 2) Coders of drivers may be tempted to code up an __exit function that is never used, just in order to satisfy the required three args of the modular registration function. 3) Non-modular code ends up including the module.h which increases CPP overhead that they don't need. 4) It hinders us from performing better separation of the module init code and the generic init code. The nature of linux means that thousands of developers are reading the code every day -- so I think that there is a genuine value in having the code convey a clear message on how it was designed to be used. Only using module related headers/macros for genuinely modular code helps us (albeit in a small way) towards achieving that. Looking at this thread, I see that one of the reasons given for this code's ambiguous module vs. built-in identity was the observation of a similar identity crisis of the related INTEL_SOC_PMIC code. Does that not back up the point above about the value in having the code speak for itself? So IMHO we probably should clarify the PMIC code vs. adding another example that looks just like it. Paul. -- I can anyway shove out these macros to end the discussion. I'd rather convince you than annoy you into doing as I suggested. BTW whether you buy the argument or not, please do treat yourself with ice cream for being able to make such a comment. Will do. Thanks, Paul Bolle -- To unsubscribe from this list: send the line unsubscribe linux-kernel in Please read the FAQ at http://www.tux.org/lkml/
Re: [Intel-gfx] [PATCH 6/8] drivers/pwm: Add Crystalcove (CRC) PWM driver
Hi Paul, On Fri, Jun 19, 2015 at 12:11 AM, Paul Bolle wrote: > Hi Shobhit, > > On Thu, 2015-06-18 at 23:24 +0530, Shobhit Kumar wrote: >> On Fri, May 1, 2015 at 2:42 AM, Paul Bolle wrote: >> > On Wed, 2015-04-29 at 19:30 +0530, Shobhit Kumar wrote: >> >> --- a/drivers/pwm/Kconfig >> >> +++ b/drivers/pwm/Kconfig >> > >> >> +config PWM_CRC >> >> + bool "Intel Crystalcove (CRC) PWM support" >> >> + depends on X86 && INTEL_SOC_PMIC >> >> + help >> >> + Generic PWM framework driver for Crystalcove (CRC) PMIC based PWM >> >> + control. >> > >> >> --- a/drivers/pwm/Makefile >> >> +++ b/drivers/pwm/Makefile >> > >> >> +obj-$(CONFIG_PWM_CRC)+= pwm-crc.o >> > >> > PWM_CRC is a bool symbol. So pwm-crc.o can never be part of a module. >> >> I actually started this as a module but later decided to make it as >> bool because INTEL_SOC_PMIC on which this depends is itself a bool as >> well. > > As does GPIO_CRYSTAL_COVE and that's a tristate. So? > >> Still it is good to keep the module based initialization. >> Firstly because it causes no harm > > If I got a dime for every time people used an argument like that I ... I > could treat myself to an ice cream. A really big ice cream. Hmm, that > doesn't sound too impressive. But still, "causes no harm" is below the > bar for kernel code. Kernel code needs to add value. > >> and even though some of the macros >> are pre-processed out, gives info about the driver. > > None of which can't be gotten elsewhere (ie, the commit message, or the > file these macro reside in). > Causes no harm comment had to be read together with more info about the driver. It causes no harm while providing more info. And as you only said those macros are pre-processed out to really the defaults for built-in drivers. So what is the exact big problem with this ? I can anyway shove out these macros to end the discussion. BTW whether you buy the argument or not, please do treat yourself with ice cream for being able to make such a comment. >> Secondly there >> were discussion on why INTEL_SOC_PMIC is bool (note this driver also >> has module based initialization even when bool). > > Yes, there's copy and paste going on even in kernel development. > There are other examples in the kernel. I just gave the one which is related as well. Regards Shobhit >> I am guessing because >> of some tricky module load order dependencies. If ever that becomes a >> module, this can mostly be unchanged to be loaded as a module. > > You put in a macro, or any other bit of code, when it's needed, not > beforehand, "just in case". That's silly. > > Thanks, > > > Paul Bolle > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [Intel-gfx] [PATCH 6/8] drivers/pwm: Add Crystalcove (CRC) PWM driver
Hi Paul, On Fri, Jun 19, 2015 at 12:11 AM, Paul Bolle pebo...@tiscali.nl wrote: Hi Shobhit, On Thu, 2015-06-18 at 23:24 +0530, Shobhit Kumar wrote: On Fri, May 1, 2015 at 2:42 AM, Paul Bolle pebo...@tiscali.nl wrote: On Wed, 2015-04-29 at 19:30 +0530, Shobhit Kumar wrote: --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig +config PWM_CRC + bool Intel Crystalcove (CRC) PWM support + depends on X86 INTEL_SOC_PMIC + help + Generic PWM framework driver for Crystalcove (CRC) PMIC based PWM + control. --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile +obj-$(CONFIG_PWM_CRC)+= pwm-crc.o PWM_CRC is a bool symbol. So pwm-crc.o can never be part of a module. I actually started this as a module but later decided to make it as bool because INTEL_SOC_PMIC on which this depends is itself a bool as well. As does GPIO_CRYSTAL_COVE and that's a tristate. So? Still it is good to keep the module based initialization. Firstly because it causes no harm If I got a dime for every time people used an argument like that I ... I could treat myself to an ice cream. A really big ice cream. Hmm, that doesn't sound too impressive. But still, causes no harm is below the bar for kernel code. Kernel code needs to add value. and even though some of the macros are pre-processed out, gives info about the driver. None of which can't be gotten elsewhere (ie, the commit message, or the file these macro reside in). Causes no harm comment had to be read together with more info about the driver. It causes no harm while providing more info. And as you only said those macros are pre-processed out to really the defaults for built-in drivers. So what is the exact big problem with this ? I can anyway shove out these macros to end the discussion. BTW whether you buy the argument or not, please do treat yourself with ice cream for being able to make such a comment. Secondly there were discussion on why INTEL_SOC_PMIC is bool (note this driver also has module based initialization even when bool). Yes, there's copy and paste going on even in kernel development. There are other examples in the kernel. I just gave the one which is related as well. Regards Shobhit I am guessing because of some tricky module load order dependencies. If ever that becomes a module, this can mostly be unchanged to be loaded as a module. You put in a macro, or any other bit of code, when it's needed, not beforehand, just in case. That's silly. Thanks, Paul Bolle -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [Intel-gfx] [PATCH 6/8] drivers/pwm: Add Crystalcove (CRC) PWM driver
Hi Shobhit, On Thu, 2015-06-18 at 23:24 +0530, Shobhit Kumar wrote: > On Fri, May 1, 2015 at 2:42 AM, Paul Bolle wrote: > > On Wed, 2015-04-29 at 19:30 +0530, Shobhit Kumar wrote: > >> --- a/drivers/pwm/Kconfig > >> +++ b/drivers/pwm/Kconfig > > > >> +config PWM_CRC > >> + bool "Intel Crystalcove (CRC) PWM support" > >> + depends on X86 && INTEL_SOC_PMIC > >> + help > >> + Generic PWM framework driver for Crystalcove (CRC) PMIC based PWM > >> + control. > > > >> --- a/drivers/pwm/Makefile > >> +++ b/drivers/pwm/Makefile > > > >> +obj-$(CONFIG_PWM_CRC)+= pwm-crc.o > > > > PWM_CRC is a bool symbol. So pwm-crc.o can never be part of a module. > > I actually started this as a module but later decided to make it as > bool because INTEL_SOC_PMIC on which this depends is itself a bool as > well. As does GPIO_CRYSTAL_COVE and that's a tristate. So? > Still it is good to keep the module based initialization. > Firstly because it causes no harm If I got a dime for every time people used an argument like that I ... I could treat myself to an ice cream. A really big ice cream. Hmm, that doesn't sound too impressive. But still, "causes no harm" is below the bar for kernel code. Kernel code needs to add value. > and even though some of the macros > are pre-processed out, gives info about the driver. None of which can't be gotten elsewhere (ie, the commit message, or the file these macro reside in). > Secondly there > were discussion on why INTEL_SOC_PMIC is bool (note this driver also > has module based initialization even when bool). Yes, there's copy and paste going on even in kernel development. > I am guessing because > of some tricky module load order dependencies. If ever that becomes a > module, this can mostly be unchanged to be loaded as a module. You put in a macro, or any other bit of code, when it's needed, not beforehand, "just in case". That's silly. Thanks, Paul Bolle -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [Intel-gfx] [PATCH 6/8] drivers/pwm: Add Crystalcove (CRC) PWM driver
On Fri, May 1, 2015 at 2:42 AM, Paul Bolle wrote:
> On Wed, 2015-04-29 at 19:30 +0530, Shobhit Kumar wrote:
>> --- a/drivers/pwm/Kconfig
>> +++ b/drivers/pwm/Kconfig
>
>> +config PWM_CRC
>> + bool "Intel Crystalcove (CRC) PWM support"
>> + depends on X86 && INTEL_SOC_PMIC
>> + help
>> + Generic PWM framework driver for Crystalcove (CRC) PMIC based PWM
>> + control.
>
>> --- a/drivers/pwm/Makefile
>> +++ b/drivers/pwm/Makefile
>
>> +obj-$(CONFIG_PWM_CRC)+= pwm-crc.o
>
> PWM_CRC is a bool symbol. So pwm-crc.o can never be part of a module.
I actually started this as a module but later decided to make it as
bool because INTEL_SOC_PMIC on which this depends is itself a bool as
well. Still it is good to keep the module based initialization.
Firstly because it causes no harm and even though some of the macros
are pre-processed out, gives info about the driver. Secondly there
were discussion on why INTEL_SOC_PMIC is bool (note this driver also
has module based initialization even when bool). I am guessing because
of some tricky module load order dependencies. If ever that becomes a
module, this can mostly be unchanged to be loaded as a module.
Regards
Shobhit
>
> (If I'm wrong, and that object file can actually be part of a module,
> you can stop reading here.)
>
>> --- /dev/null
>> +++ b/drivers/pwm/pwm-crc.c
>
>> +#include
>
> Perhaps this include is not needed.
>
>> +static const struct pwm_ops crc_pwm_ops = {
>> + .config = crc_pwm_config,
>> + .enable = crc_pwm_enable,
>> + .disable = crc_pwm_disable,
>> + .owner = THIS_MODULE,
>
> For built-in only code THIS_MODULE is basically equivalent to NULL (see
> include/linux/export.h). So I guess this line can be dropped.
>
>> +};
>
>> +static struct platform_driver crystalcove_pwm_driver = {
>> + .probe = crystalcove_pwm_probe,
>> + .remove = crystalcove_pwm_remove,
>> + .driver = {
>> + .name = "crystal_cove_pwm",
>> + },
>> +};
>> +
>> +module_platform_driver(crystalcove_pwm_driver);
>
> Speaking from memory: for built-in only code this is equivalent to
> calling
> platform_driver_register(_pwm_driver);
>
> from a wrapper, and marking that wrapper with device_initcall().
>
>> +MODULE_AUTHOR("Shobhit Kumar ");
>> +MODULE_DESCRIPTION("Intel Crystal Cove PWM Driver");
>> +MODULE_LICENSE("GPL v2");
>
> These macros will be effectively preprocessed away for built-in only
> code.
>
>
> Paul Bolle
>
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Re: [Intel-gfx] [PATCH 6/8] drivers/pwm: Add Crystalcove (CRC) PWM driver
On Fri, May 1, 2015 at 2:42 AM, Paul Bolle pebo...@tiscali.nl wrote:
On Wed, 2015-04-29 at 19:30 +0530, Shobhit Kumar wrote:
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
+config PWM_CRC
+ bool Intel Crystalcove (CRC) PWM support
+ depends on X86 INTEL_SOC_PMIC
+ help
+ Generic PWM framework driver for Crystalcove (CRC) PMIC based PWM
+ control.
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
+obj-$(CONFIG_PWM_CRC)+= pwm-crc.o
PWM_CRC is a bool symbol. So pwm-crc.o can never be part of a module.
I actually started this as a module but later decided to make it as
bool because INTEL_SOC_PMIC on which this depends is itself a bool as
well. Still it is good to keep the module based initialization.
Firstly because it causes no harm and even though some of the macros
are pre-processed out, gives info about the driver. Secondly there
were discussion on why INTEL_SOC_PMIC is bool (note this driver also
has module based initialization even when bool). I am guessing because
of some tricky module load order dependencies. If ever that becomes a
module, this can mostly be unchanged to be loaded as a module.
Regards
Shobhit
(If I'm wrong, and that object file can actually be part of a module,
you can stop reading here.)
--- /dev/null
+++ b/drivers/pwm/pwm-crc.c
+#include linux/module.h
Perhaps this include is not needed.
+static const struct pwm_ops crc_pwm_ops = {
+ .config = crc_pwm_config,
+ .enable = crc_pwm_enable,
+ .disable = crc_pwm_disable,
+ .owner = THIS_MODULE,
For built-in only code THIS_MODULE is basically equivalent to NULL (see
include/linux/export.h). So I guess this line can be dropped.
+};
+static struct platform_driver crystalcove_pwm_driver = {
+ .probe = crystalcove_pwm_probe,
+ .remove = crystalcove_pwm_remove,
+ .driver = {
+ .name = crystal_cove_pwm,
+ },
+};
+
+module_platform_driver(crystalcove_pwm_driver);
Speaking from memory: for built-in only code this is equivalent to
calling
platform_driver_register(crystalcove_pwm_driver);
from a wrapper, and marking that wrapper with device_initcall().
+MODULE_AUTHOR(Shobhit Kumar shobhit.ku...@intel.com);
+MODULE_DESCRIPTION(Intel Crystal Cove PWM Driver);
+MODULE_LICENSE(GPL v2);
These macros will be effectively preprocessed away for built-in only
code.
Paul Bolle
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Re: [Intel-gfx] [PATCH 6/8] drivers/pwm: Add Crystalcove (CRC) PWM driver
Hi Shobhit, On Thu, 2015-06-18 at 23:24 +0530, Shobhit Kumar wrote: On Fri, May 1, 2015 at 2:42 AM, Paul Bolle pebo...@tiscali.nl wrote: On Wed, 2015-04-29 at 19:30 +0530, Shobhit Kumar wrote: --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig +config PWM_CRC + bool Intel Crystalcove (CRC) PWM support + depends on X86 INTEL_SOC_PMIC + help + Generic PWM framework driver for Crystalcove (CRC) PMIC based PWM + control. --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile +obj-$(CONFIG_PWM_CRC)+= pwm-crc.o PWM_CRC is a bool symbol. So pwm-crc.o can never be part of a module. I actually started this as a module but later decided to make it as bool because INTEL_SOC_PMIC on which this depends is itself a bool as well. As does GPIO_CRYSTAL_COVE and that's a tristate. So? Still it is good to keep the module based initialization. Firstly because it causes no harm If I got a dime for every time people used an argument like that I ... I could treat myself to an ice cream. A really big ice cream. Hmm, that doesn't sound too impressive. But still, causes no harm is below the bar for kernel code. Kernel code needs to add value. and even though some of the macros are pre-processed out, gives info about the driver. None of which can't be gotten elsewhere (ie, the commit message, or the file these macro reside in). Secondly there were discussion on why INTEL_SOC_PMIC is bool (note this driver also has module based initialization even when bool). Yes, there's copy and paste going on even in kernel development. I am guessing because of some tricky module load order dependencies. If ever that becomes a module, this can mostly be unchanged to be loaded as a module. You put in a macro, or any other bit of code, when it's needed, not beforehand, just in case. That's silly. Thanks, Paul Bolle -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
