Re: [PATCH v2 0/7] Rust Abstractions for PWM subsystem with TH1520 PWM driver

From: Drew Fustini <drew@pdp7.com>
To: Michal Wilczynski <m.wilczynski@samsung.com>
Cc: "Uwe Kleine-König" <ukleinek@kernel.org>,
	"Miguel Ojeda" <ojeda@kernel.org>,
	"Alex Gaynor" <alex.gaynor@gmail.com>,
	"Boqun Feng" <boqun.feng@gmail.com>,
	"Gary Guo" <gary@garyguo.net>,
	"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
	"Andreas Hindborg" <a.hindborg@kernel.org>,
	"Alice Ryhl" <aliceryhl@google.com>,
	"Trevor Gross" <tmgross@umich.edu>,
	"Danilo Krummrich" <dakr@kernel.org>,
	"Guo Ren" <guoren@kernel.org>, "Fu Wei" <wefu@redhat.com>,
	"Rob Herring" <robh@kernel.org>,
	"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
	"Conor Dooley" <conor+dt@kernel.org>,
	"Paul Walmsley" <paul.walmsley@sifive.com>,
	"Palmer Dabbelt" <palmer@dabbelt.com>,
	"Albert Ou" <aou@eecs.berkeley.edu>,
	"Alexandre Ghiti" <alex@ghiti.fr>,
	"Marek Szyprowski" <m.szyprowski@samsung.com>,
	"Benno Lossin" <lossin@kernel.org>,
	"Michael Turquette" <mturquette@baylibre.com>,
	"Stephen Boyd" <sboyd@kernel.org>,
	linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
	rust-for-linux@vger.kernel.org, linux-riscv@lists.infradead.org,
	devicetree@vger.kernel.org, linux-clk@vger.kernel.org
Subject: Re: [PATCH v2 0/7] Rust Abstractions for PWM subsystem with TH1520 PWM driver
Date: Thu, 12 Jun 2025 10:49:38 -0700	[thread overview]
Message-ID: <aEsTMrdmC7drMJIs@x1> (raw)
In-Reply-To: <b3252042-e7fd-4ac9-a4ad-0226d21fd477@samsung.com>

On Thu, Jun 12, 2025 at 03:27:09PM +0200, Michal Wilczynski wrote:
> 
> 
> On 6/12/25 07:01, Uwe Kleine-König wrote:
> > Hello Drew,
> > 
> > On Wed, Jun 11, 2025 at 04:52:22PM -0700, Drew Fustini wrote:
> >> I also enabled the pwm fan driver. However, there is a probe failure:
> >>
> >> [    1.250921] pwm-fan pwm-fan: Failed to configure PWM: -524
> >> [    1.256546] pwm-fan pwm-fan: probe with driver pwm-fan failed with error -524
> > 
> > 524 = ENOTSUPP, so it seems the request had duty_offset > 0. Does your
> > fan use PWM_POLARITY_INVERTED? If so, try without that flag. If your fan
> > really needs an inverted PWM this of course makes fan control buggy.
> > With the next revision it should work fine (as a duty_offset > 0 should
> > get rounded down to 0).
> 
> Since we're running the same DT, the polarity shouldn't be inverted. I
> see you have CONFIG_PWM_DEBUG=y enabled, which is most likely the reason
> the probe fails.

Thanks, I've disabled that options and the probe completes okay. The fan
is now spinning :)

Drew