linux-kernel - RE: [PATCH v3 0/3] Platform support for EHRPWM & ECAP devices in DAVINCI.

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Date:	Thu, 4 Apr 2013 10:10:17 +0000
From:	"Philip, Avinash" <avinashphilip@...com>
To:	"Nori, Sekhar" <nsekhar@...com>
CC:	"linux@....linux.org.uk" <linux@....linux.org.uk>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"davinci-linux-open-source@...ux.davincidsp.com" 
	<davinci-linux-open-source@...ux.davincidsp.com>,
	"Manjunathappa, Prakash" <prakash.pm@...com>,
	"jacmet@...site.dk" <jacmet@...site.dk>
Subject: RE: [PATCH v3 0/3] Platform support for EHRPWM & ECAP devices in
 DAVINCI.

On Thu, Apr 04, 2013 at 12:07:44, Philip, Avinash wrote:
> On Thu, Apr 04, 2013 at 11:19:44, Nori, Sekhar wrote:
> > On 4/4/2013 10:09 AM, Philip, Avinash wrote:
> > > On Tue, Apr 02, 2013 at 14:05:09, Nori, Sekhar wrote:
> > >> On 3/25/2013 1:19 PM, Philip Avinash wrote:
> > >>> Add platform support for EHRPWM and ECAP by providing clock nodes and
> > >>> device tree nodes.
> > >>> This series depends on [1] and [2] and is available for testing at [3].
> > >>> Tested for back light support in da850 EVM with EHRPWM PWM device.
> > >>>
> > >>> [1] http://gitorious.org/linux-davinci/linux-davinci/trees/davinci-for-v3.9/dt-2
> > >>> [2] https://gitorious.org/linux-pwm/linux-pwm/trees/for-next
> > >>> [3] https://github.com/avinashphilip/am335x_linux/tree/davinci-for-v3.9_soc_pwm
> > >>>
> > >>> Note:
> > >>> DT support for EHRPWM backlight has not been added in da850-evm.dts as there is
> > >>> conflicting pin-mux requirement with SPI flash.
> > >>
> > >> Can you check if this is really true even in newer boards (have a look
> > >> at the latest schematics)? I remember this used to be a problem in very
> > >> early versions but was fixed later.
> > > 
> > > On looking schematics, panel has three power controls LCD_BACKLIGHT_PWR, LCD_PANEL_PWR,
> > > LCD_PWM0. On latest schematic, LCD_PWM0 is connected to ECAP instance 2. So backlight
> > > can control through ECAP2 (not conflicting with SPI1 cs0). Still for controlling
> > > backlight, require support for LCD_BACKLIGHT_PWR & LCD_PANEL_PWR. These signals
> > 
> > By controlling above you mean "switching on/off"? Otherwise this seems
> > to be contradicting the statement just before.
> 
> Yes these lines should be switching on/off.
> 
> > 
> > > to be controlled by GPIO 2[8] & GPIO 2[15]. In release platform callbacks used
> > > to control GPIO functionality. But with DT support, I have to check how platform
> > > callbacks can be used.
> > 
> > Platform callbacks are not possible with DT.
> 
> Ok.
> 
> > You can look at what freescale mxsfb.c does. Look for panel-enable-gpios DT binding.
> 
> I will use GPIO pin configuration info from DT nodes. From probe GPIO pin make active and
> in remove disable GPIO pin.

For passing from GPIO pins from DT, GPIO DT node has to be populated. So this has dependency
on GPIO driver conversion for davinci platforms.

Thanks
Avinash

> 
> Thanks
> Avinash
> 
> > 
> > Thanks,
> > Sekhar
> > 
> 
>