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RE: [PATCH 1/7] pwm: Add pwm core driver

To: Jassi Brar <jassisinghbrar@gmail.com>
Subject: RE: [PATCH 1/7] pwm: Add pwm core driver
From: Arun MURTHY <arun.murthy@stericsson.com>
Date: Fri, 1 Oct 2010 10:46:15 +0200
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Thread-topic: [PATCH 1/7] pwm: Add pwm core driver
> On Fri, Oct 1, 2010 at 4:25 PM, Arun MURTHY
> <arun.murthy@stericsson.com> wrote:
> > You can have a look at the pwm_config_nosleep(),pwm_set_polarity(),
> > pwm_synchronize(),pwm_unsynchronize(), pwm_set_handler() etc.
> > These are not being used by the exsting pwm drivers except Atmel pwm.
> How would your 'simple' driver handle Atmel then ?
> What if future's SoCs start providing those 'advance' features like
> Atmel's ?
> 
The pwm core driver is the intersection of all pwm drivers and not union
of all pwm driver. I refer this as simple pwm core driver / framework.
Atmel pwm is of a separate classification.
It includes GPIO also. Though, Atmel can use the pwm core driver framework
for functionalities like pwm_enable, pwm_disable, pwm_config, etc and remaining
functionalities specific to Atmel will be handled in Atlmel pwm driver and
will not be exposed to the entire kernel.
Its that the present day pwm device that has been made easy though, by providing
the same functionality.

> > I mean not the functions but the functionality.
> > PWM is a simple device and most of its clients are controlling
> intensity
> > of backlight, leds, vibrator etc.
> > I don't think these complex functionality are required.
> oh dear !
Here I mean why should all those function be exposed to the entire kernel,
as most of the pwm devices do not use them.

Thanks and Regards,
Arun R Murthy
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