From: Lee Jones <lee@kernel.org>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Shree Ramamoorthy <s-ramamoorthy@ti.com>,
Julien Panis <jpanis@baylibre.com>,
Gairuboina Sirisha <sirisha.gairuboina@ltts.com>,
arnd@arndb.de, krzysztof.kozlowski+dt@linaro.org,
linux-kernel@vger.kernel.org, d-gole@ti.com
Subject: Re: [PATCH v1 0/3] TPS65224 PMIC driver
Date: Fri, 17 Nov 2023 11:05:33 +0000 [thread overview]
Message-ID: <20231117110533.GA8822@google.com> (raw)
In-Reply-To: <2023111007-siamese-crepe-9775@gregkh>
On Fri, 10 Nov 2023, Greg KH wrote:
> On Thu, Nov 09, 2023 at 10:22:00AM -0600, Shree Ramamoorthy wrote:
> > > I compared 'tps65224.h' with 'tps6594.h', especially register mapping.
> > > There are less resources in TPS65224, but I don't see any incompatibility
> > > between both PMIC register mappings. Some registers are not used by
> > > your TPS65224, and some interrupts are not used either (that's not a
> > > problem, they will not trigger, so). Beyond that, I2C and PFSM drivers
> > > perform the same things for both PMICs. That's why according to me,
> > > nothing prevents from re-using TPS6594 drivers. Even for ADC, which is
> > > specific to your TPS65224 indeed, the register range does not overlap
> > > with any of TPS6594 registers. You could conditionally add this driver
> > > (that's what we did in 'tps6594-core.c' for RTC driver, which is not
> > > used
> > > for one of the compatibles: you can do something similar for ADC).
> > > You will probably add support for others TPS65224 drivers over the next
> > > weeks: SPI, ESM, RTC, GPIOs, regulators, watchdog, and ADC. Most of them
> > > should be compatible with both TPS6594 and TPS65224, I think (even
> > > watchdog driver, which was not developed for TPS6594). ADC will not,
> > > but as explained above you can easily deal with this one thanks to
> > > the compatible.
> > > For 'tps65224-core.c' only, a little bit of work might be necessary to
> > > handle your TPS65224 specific functionalities. By using a different DT
> > > compatible string, your driver can then select different options (or
> > > maybe
> > > even different register ranges) for some features based on the
> > > compatible.
> > > But except for 'tps65xx-core.c', there is "sufficient overlap" to justify
> > > sharing as much as possible between TPS65224 and TPS6594, in my
> > > opinion.
> >
> >
> > TI is positioning TPS65224 as a separate family from TPS6594, but shared
> > software drivers for PMICs that have different use cases would lead to
> > confusion.
>
> Why? No one cares what a driver's name is, only that it works for their
> hardware. What different "use case" would cause problems here?
>
> > Re-scoping the project to accommodate these suggestions would
> > negatively affect the timeline we are trying to meet.
>
> There are no timelines/deadlines with kernel development, sorry, that's
> not our issue.
>
> > We want to include the
> > restructure that addresses the compatibility, register maps, and
> > functionality similarities, but it would best solved after the upcoming
> > deadline has been met.
>
> Again, no deadline here. Please do the work properly, that's all we
> care about.
>
> > With the growth of PMIC software device drivers, we
> > would prefer to have a separate series with the suggested changes and proper
> > naming convention to address that while they overlap, the two PMICs devices
> > are not a subset.
>
> Why does the name matter? Again, all that a user cares about is if
> their hardware device is supported, the name means nothing here.
>
> Please do the correct thing and add support for this device to the
> existing drivers, that's the correct thing to do. You will save time
> and energy and code in the long-run, which is the important thing.
>
> There is a reason that Linux drivers are, on average, 1/3 smaller than
> other operating systems. And that's because they share common code with
> other drivers. You aren't allowed to just copy an existing one and add
> a few changes and make a whole new driver, you need to modify the
> current one.
>
> thanks,
>
> greg k-h
Ha! You took the words right out of my mouth!
Thanks.
--
Lee Jones [李琼斯]
prev parent reply other threads:[~2023-11-17 11:05 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-26 13:32 [PATCH v1 0/3] TPS65224 PMIC driver Gairuboina Sirisha
2023-10-26 13:32 ` [PATCH v1 1/3] drivers: mfd: Add support for TPS65224 Gairuboina Sirisha
2023-10-27 7:02 ` Greg KH
2023-11-07 11:40 ` Gairuboina Sirisha
2023-10-26 13:32 ` [PATCH v1 2/3] drivers: mfd: Add support for TPS65224 i2c driver Gairuboina Sirisha
2023-10-27 7:02 ` Greg KH
2023-11-07 11:42 ` Gairuboina Sirisha
2023-10-27 8:08 ` Krzysztof Kozlowski
2023-11-07 11:50 ` Gairuboina Sirisha
2023-10-26 13:32 ` [PATCH v1 3/3] drivers: misc: Add support for TPS65224 pfsm driver Gairuboina Sirisha
2023-10-27 7:05 ` Greg KH
2023-11-07 11:44 ` Gairuboina Sirisha
2023-10-27 8:05 ` Krzysztof Kozlowski
2023-11-07 11:48 ` Gairuboina Sirisha
2023-11-03 8:52 ` [PATCH v1 0/3] TPS65224 PMIC driver Julien Panis
2023-11-07 11:37 ` Gairuboina Sirisha
2023-11-08 9:19 ` Julien Panis
2023-11-09 16:22 ` Shree Ramamoorthy
2023-11-10 4:26 ` Greg KH
2023-11-10 20:07 ` [EXTERNAL] " Shree Ramamoorthy
2023-11-17 11:05 ` Lee Jones [this message]
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