Subject: [PATCH v3 0/3] Platform support for EHRPWM & ECAP devices in DAVINCI.

From: [email-masked] (Sekhar Nori)
Date: Thu, 4 Apr 2013 11:19:44 +0530

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.

> 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. You can look at what
freescale mxsfb.c does. Look for panel-enable-gpios DT binding.

Thanks,
Sekhar