linux-kernel - RE: [PATCH V17 3/3] Input: new da7280 haptic driver

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Message-ID: <DB8PR10MB343624BF003338E8B34439AC85770@DB8PR10MB3436.EURPRD10.PROD.OUTLOOK.COM>
Date:   Fri, 24 Jul 2020 05:47:04 +0000
From:   Roy Im <roy.im.opensource@...semi.com>
To:     Randy Dunlap <rdunlap@...radead.org>,
        Roy Im <roy.im.opensource@...semi.com>,
        Uwe Kleine-Koenig <u.kleine-koenig@...gutronix.de>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Brian Masney <masneyb@...tation.org>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Greg KH <gregkh@...uxfoundation.org>,
        Lee Jones <lee.jones@...aro.org>, Luca Weiss <luca@...tu.xyz>,
        Maximilian Luz <luzmaximilian@...il.com>,
        Pascal PAILLET-LME <p.paillet@...com>,
        Rob Herring <robh@...nel.org>,
        Samuel Ortiz <sameo@...ux.intel.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>
CC:     Support Opensource <Support.Opensource@...semi.com>,
        "linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-pwm@...r.kernel.org" <linux-pwm@...r.kernel.org>
Subject: RE: [PATCH V17 3/3] Input: new da7280 haptic driver

Friday, July 24, 2020 11:57 AM, Randy Dunlap wrote 
> On 7/23/20 6:54 PM, Roy Im wrote:
> > On Fri, July 24, 2020 5:51 AM, Randy Dunlap wrote
> >> On 7/23/20 8:01 AM, Roy Im wrote:
> >>> diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
> >>> index 362e8a0..06dc5a3 100644
> >>> --- a/drivers/input/misc/Kconfig
> >>> +++ b/drivers/input/misc/Kconfig
> >>> @@ -869,4 +869,17 @@ config INPUT_STPMIC1_ONKEY
> >>>  	  To compile this driver as a module, choose M here: the
> >>>  	  module will be called stpmic1_onkey.
> >>>
> >>> +config INPUT_DA7280_HAPTICS
> >>> +	tristate "Dialog Semiconductor DA7280 haptics support"
> >>> +	depends on INPUT && I2C
> >>> +	select INPUT_FF_MEMLESS
> >>> +	select REGMAP_I2C
> >>> +	help
> >>> +	  Say Y to enable support for the Dialog DA7280 haptics driver.
> >>> +	  The haptics can be controlled by I2C communication,
> >>> +	  or by PWM input, or by GPI.
> >>
> >> 	  Is that                GPIO.
> >> ?
> > The Haptics can be working by GPI(if see from the haptic device), but from the Host it is GPO. Do you think the GPIO is
> correct?
> 
> To me it needs to represent what services/interfaces/facilities are used by this driver that are provided by the Linux kernel.
> If it uses Linux GPIO services, then it should say GPIO -- although I don't see it using any Linux GPIO services.

OK, let me change to GPIO.

> 
> >>
> >> Can the haptics be controlled only by PWM or only by GPI(O)?
> >>
> >> Just curious: why is I2C required to build the driver if a user is only controlling the device by PWM or GPI?
> >
> > I2C is required to control registers and it can be triggered by I2C or PWM or GPI(controlled by host outside this driver),
> so PWM and GPI are optional.
> > With your comments, I think it's better to remove below lines(//remove) to avoid confusion and add PWM as below if
> you agree.
> >          // remove
> > 	  The haptics can be controlled by I2C communication,
> > 	  or by PWM input, or by GPI.
> >          // update, adding || PWM
> >          depends on (INPUT && I2C) || PWM
> 
> Since <linux/pwm.h> provides stubs for when CONFIG_PWM is not enabled, it appears that "depends on  PWM" is not
> required.
> 
> I'll leave it up to you. I was just trying to understand better.
> It may be that no changes are needed.

OK, thanks for your comments. To be clearer, I would like to update as below if you agree
	
	depends on INPUT && I2C
...
	The haptics can be controlled by PWM or GPIO
	with I2C communication.
> 
> 
> thanks.
> --
> ~Randy

Kind regards,
Roy