Re: [PATCH 1/2] pwm: make it possible to apply pwm changes in atomic context

From: Thierry Reding <thierry.reding@gmail.com>
To: Sean Young <sean@mess.org>
Cc: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	"Shawn Guo" <shawnguo@kernel.org>,
	"Sascha Hauer" <s.hauer@pengutronix.de>,
	"Pengutronix Kernel Team" <kernel@pengutronix.de>,
	"Fabio Estevam" <festevam@gmail.com>,
	"NXP Linux Team" <linux-imx@nxp.com>,
	"Vladimir Zapolskiy" <vz@mleia.com>,
	"Conor Dooley" <conor.dooley@microchip.com>,
	"Daire McNamara" <daire.mcnamara@microchip.com>,
	"Palmer Dabbelt" <palmer@dabbelt.com>,
	"Paul Walmsley" <paul.walmsley@sifive.com>,
	"Fabrice Gasnier" <fabrice.gasnier@foss.st.com>,
	"Maxime Coquelin" <mcoquelin.stm32@gmail.com>,
	"Alexandre Torgue" <alexandre.torgue@foss.st.com>,
	"Ivaylo Dimitrov" <ivo.g.dimitrov.75@gmail.com>,
	linux-pwm@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-riscv@lists.infradead.org,
	linux-stm32@st-md-mailman.stormreply.com
Subject: Re: [PATCH 1/2] pwm: make it possible to apply pwm changes in atomic context
Date: Fri, 6 Oct 2023 12:29:34 +0200	[thread overview]
Message-ID: <ZR_hjjS1VMAPLYVI@orome.fritz.box> (raw)
In-Reply-To: <1bd5241d584ceb4d6b731c4dc3203fb9686ee1d1.1696156485.git.sean@mess.org>

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On Sun, Oct 01, 2023 at 11:40:29AM +0100, Sean Young wrote:
[...]
> diff --git a/include/linux/pwm.h b/include/linux/pwm.h
> index d2f9f690a9c1..c94894ffa4c4 100644
> --- a/include/linux/pwm.h
> +++ b/include/linux/pwm.h
> @@ -287,6 +287,7 @@ struct pwm_ops {
>   * @ops: callbacks for this PWM controller
>   * @base: number of first PWM controlled by this chip
>   * @npwm: number of PWMs controlled by this chip
> + * @can_sleep: can the driver sleep in pwm_apply_state
>   * @of_xlate: request a PWM device given a device tree PWM specifier
>   * @of_pwm_n_cells: number of cells expected in the device tree PWM specifier
>   * @list: list node for internal use
> @@ -297,6 +298,7 @@ struct pwm_chip {
>  	const struct pwm_ops *ops;
>  	int base;
>  	unsigned int npwm;
> +	bool can_sleep;

Can we please call this "might_sleep"?

>  
>  	struct pwm_device * (*of_xlate)(struct pwm_chip *chip,
>  					const struct of_phandle_args *args);
> @@ -380,6 +382,18 @@ static inline void pwm_disable(struct pwm_device *pwm)
>  	pwm_apply_state(pwm, &state);
>  }
>  
> +/**
> + * pwm_can_sleep() - can a pwm driver sleep in pwm_apply_state()
> + * @pwm: PWM device
> + *
> + * Returns: true if the driver may sleep, false if pwm_apply_state()
> + * can be called from atomic context.
> + */
> +static inline bool pwm_can_sleep(struct pwm_device *pwm)

And this one pwm_might_sleep()? I don't see why we need to deviate from
the nomenclature that the core introduced.

Thierry

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