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Date: Tue, 11 Jun 2024 08:50:44 +0000
From: Tzung-Bi Shih <tzungbi@kernel.org>
To: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= <ukleinek@baylibre.com>
Cc: Benson Leung <bleung@chromium.org>, Guenter Roeck <groeck@chromium.org>,
	linux-pwm@vger.kernel.org, chrome-platform@lists.linux.dev,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] pwm: cros-ec: Don't care about consumers in
 .get_state()
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References: <20240607084416.897777-5-u.kleine-koenig@baylibre.com>
 <20240607084416.897777-6-u.kleine-koenig@baylibre.com>
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In-Reply-To: <20240607084416.897777-6-u.kleine-koenig@baylibre.com>

On Fri, Jun 07, 2024 at 10:44:15AM +0200, Uwe Kleine-K?nig wrote:
> The get_state() callback is never called (in a visible way) after there
> is a consumer for a pwm device. The core handles loosing the information
> about duty_cycle just fine.

ChromeOS EC has no separated "enabled" state, it sees `duty == 0` as
"disabled"[1].  1db37f9561b2 ("pwm: cros-ec: Cache duty cycle value")
caches the value in kernel side so that it can retrieve the original duty
value even if (struct pwm_state *)->enabled is false.

To make sure I understand, did you mean the original duty value could be less
important because:
- We are less caring as it is in a debug context at [2]?
- At [3], the PWM device is still initializing.

[1]: https://crrev.com/0e16954460a08133b2557150e0897014ea2b9672/common/pwm.c#66
[2]: https://elixir.bootlin.com/linux/v6.10-rc3/source/drivers/pwm/core.c#L52
[3]: https://elixir.bootlin.com/linux/v6.10-rc3/source/drivers/pwm/core.c#L371