Re: [PATCH v6 1/4] Runtime Interpreted Power Sequences

On Thu, 2012-09-13 at 09:18 +0200, Sascha Hauer wrote:

On Thu, Sep 13, 2012 at 10:03:27AM +0300, Tomi Valkeinen wrote:

quoted

On Thu, 2012-09-13 at 09:00 +0200, Sascha Hauer wrote:

quoted

On Thu, Sep 13, 2012 at 09:54:09AM +0300, Tomi Valkeinen wrote:

quoted

On Thu, 2012-09-13 at 15:36 +0900, Alex Courbot wrote:

quoted

On Thursday 13 September 2012 14:22:57 Tomi Valkeinen wrote:
 

quoted

However, I fear these board specific things may be quite a bit anything,
so it may well be pwm, gpios and regulators are not enough for them. For
example, there could be an FPGA on the board which requires some
configuration to accomplish the task at hand. It could be rather
difficult to handle it with a generic power sequence.

Right. Note that this framework is supposed to be extended - I would like to 
at least add regulator voltage setting, and maybe even support for clocks and 
pinmux (but that might be out of place).

Yes, that's one concern of mine... I already can imagine someone
suggesting adding conditionals to the power sequence data. Perhaps also
direct memory read/writes so you can twiddle registers directly.

These memory writes can be avoided when these registers are abstracted
as a regular gpio/regulator/pwm driver.

Only if they are gpios/regulators/pwms. Yes, I agree most of the
possible things to configure would be among those (or perhaps
pinmuxing). But there's always the odd one that's not one of those.

quoted

Do you have examples of board specific power sequences or such?

Sure, tons of. One board needs a gpio to be set high to enable backlight,
the next one to low, a regulator has to be enabled, and to avoid
flickering a certain timing has to be ensured. This is all highly board
specific.

Okay. In my experience these have always been device specific. In the
case of backlight, the backlight device requires one gpio to be set
high, other one low, etc.

Can you share a bit more what kind of HW configuration you have that
requires this? The backlight is not a single piece of HW added to the
board (or embedded into a panel module), but consists of multiple HW
blocks integrated in a custom way to the board?

 Tomi