[PATCH v2 10/16] pwm: Add PWM modes

On Mon, Jan 22, 2018 at 2:54 AM, Claudiu Beznea
[off-list ref] wrote:

On 20.01.2018 00:34, Rob Herring wrote:

quoted

On Fri, Jan 12, 2018 at 04:22:57PM +0200, Claudiu Beznea wrote:

quoted

Define a macros for PWM modes to be used by device tree sources.

Signed-off-by: Claudiu Beznea <redacted>
---
 include/dt-bindings/pwm/pwm.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/dt-bindings/pwm/pwm.h b/include/dt-bindings/pwm/pwm.h
index ab9a077e3c7d..b8617431f8ec 100644
--- a/include/dt-bindings/pwm/pwm.h
+++ b/include/dt-bindings/pwm/pwm.h

@@ -12,4 +12,7 @@

 #define PWM_POLARITY_INVERTED                       (1 << 0)

+#define PWM_DTMODE_NORMAL                   (1 << 0)

Bit 0 is already taken. I think you mean (0 << 1)?

I wanted to have the PWM modes in a new cell, so that the pwms binding to be
something like:
pwms=<pwm-controller pwm-channel pwm-period pwm-flags pwm-mode>

If you think it is mode feasible to also include PWM mode in the cell for
PWM flags, please let me know.

Yes, but you have to make "normal" be no bit set to be compatible with
everything already out there.

quoted

Personally, I'd just drop this define. A define for a 0 value makes more
sense when each state is equally used (like active high or low), but if
0 is the more common case, then I don't the need for a define.

I want it to have these defines like bit defines:
PWM_DTMODE_NORMAL=0x1
PWM_DTMODE_COMPLEMENTARY=0x2
PWM_DTMODE_PUSH_PULL=0x4

Thinking about this some more, shouldn't the new modes just be
implied? A client is going to require one of these modes or it won't
work right.

Also complementary mode could be accomplished with a single pwm output
and a board level inverter, right? How would that be handled when the
PWM driver doesn't support that mode?

Rob