linux-kernel - Re: [PATCH v2 0/2] drivers: provide devm_platform_request

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Date:   Sun, 24 May 2020 01:09:33 +0800
From:   Dejin Zheng <zhengdejin5@...il.com>
To:     Wolfram Sang <wsa@...nel.org>
Cc:     gregkh@...uxfoundation.org, rafael@...nel.org,
        f.fainelli@...il.com, rjui@...adcom.com, sbranden@...adcom.com,
        michal.simek@...inx.com, baruch@...s.co.il, paul@...pouillou.net,
        khilman@...libre.com, shawnguo@...nel.org, festevam@...il.com,
        vz@...ia.com, heiko@...ech.de, linus.walleij@...aro.org,
        baohua@...nel.org, ardb@...nel.org, linux-i2c@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 0/2] drivers: provide devm_platform_request_irq()

On Sat, May 23, 2020 at 06:08:29PM +0200, Wolfram Sang wrote:
> On Sat, May 23, 2020 at 10:51:55PM +0800, Dejin Zheng wrote:
> > It will call devm_request_irq() after platform_get_irq() function
> > in many drivers, sometimes, it is not right for the error handling
> > of these two functions in some drivers. so provide this function
> > to simplify the driver.
> > 
> > the first patch will provide devm_platform_request_irq(), and the
> > other patch will convert to devm_platform_request_irq() in some
> > i2c bus dirver.
> > 
> > v1 -> v2:
> > 	- I give up this series of patches in v1 version. I resend this
> > 	  patches v2 by that discussion:
> > 	  https://patchwork.ozlabs.org/project/linux-i2c/patch/20200520144821.8069-1-zhengdejin5@gmail.com/
> > 	  The patch content has not changed.
> 
> I don't understand. v1 has been nacked because of technical reasons. How
> did the discussion above change the situation? Am I missing something?
>
No, you are not missing something. Maybe I did not explain clearly.

The v1 has been nacked because Grygorii told me that the
function platform_get_irq() should be done as early as possible to avoid
unnecessary initialization steps, and the function devm_request_irq()
should be done late in probe when driver and HW are actually ready to
handle IRQs. It can do the other things between the two funtions. I agree
with him that it may be necessary in some complex drives. So abandon the
patch v1.

Base on the discussion of you and Michal, I think maybe this patch is also
needed for the simple driver or the driver of already use it like that:
	
	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return irq;
	ret = devm_request_irq()

It provides a common error handling and reduce one function call for each
drivers, more easier to use and simplify code. So resend it.

BR,
Dejin

> > 
> > Dejin Zheng (2):
> >   drivers: provide devm_platform_request_irq()
> >   i2c: busses: convert to devm_platform_request_irq()
> > 
> >  drivers/base/platform.c            | 33 ++++++++++++++++++++++++++++++
> >  drivers/i2c/busses/i2c-bcm-kona.c  | 16 +++------------
> >  drivers/i2c/busses/i2c-cadence.c   | 10 +++------
> >  drivers/i2c/busses/i2c-digicolor.c | 10 +++------
> >  drivers/i2c/busses/i2c-emev2.c     |  5 ++---
> >  drivers/i2c/busses/i2c-jz4780.c    |  5 ++---
> >  drivers/i2c/busses/i2c-meson.c     | 13 ++++--------
> >  drivers/i2c/busses/i2c-mxs.c       |  9 +++-----
> >  drivers/i2c/busses/i2c-pnx.c       |  9 ++------
> >  drivers/i2c/busses/i2c-rcar.c      |  9 +++-----
> >  drivers/i2c/busses/i2c-rk3x.c      | 14 +++----------
> >  drivers/i2c/busses/i2c-sirf.c      | 10 ++-------
> >  drivers/i2c/busses/i2c-stu300.c    |  4 ++--
> >  drivers/i2c/busses/i2c-synquacer.c | 12 +++--------
> >  include/linux/platform_device.h    |  4 ++++
> >  15 files changed, 72 insertions(+), 91 deletions(-)
> > 
> > -- 
> > 2.25.0
> >