linux-kernel - Re: [PATCH] remoteproc: imx_rproc: replace devm_clk_get() with devm_clk_get

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Message-ID: <aAkf6bxBLjgFjvIZ@p14s>
Date: Wed, 23 Apr 2025 11:14:17 -0600
From: Mathieu Poirier <mathieu.poirier@...aro.org>
To: Hiago De Franco <hiagofranco@...il.com>, daniel.baluta@....com,
	iuliana.prodan@....nxp.com
Cc: linux-remoteproc@...r.kernel.org,
	Bjorn Andersson <andersson@...nel.org>,
	Shawn Guo <shawnguo@...nel.org>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Pengutronix Kernel Team <kernel@...gutronix.de>,
	Fabio Estevam <festevam@...il.com>, imx@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Hiago De Franco <hiago.franco@...adex.com>
Subject: Re: [PATCH] remoteproc: imx_rproc: replace devm_clk_get() with
 devm_clk_get_optional()

Good morning,

On Wed, Apr 23, 2025 at 12:51:31PM -0300, Hiago De Franco wrote:
> From: Hiago De Franco <hiago.franco@...adex.com>
> 
> The "clocks" device tree property is not mandatory, and if not provided
> Linux will shut down the remote processor power domain during boot if it
> is not present, even if it is running (e.g. it was started by U-Boot's
> bootaux command).

If a clock is not present imx_rproc_probe() will fail, the clock will remain
unused and Linux will switch it off.  I think that is description of what is
happening.

> 
> Use the optional devm_clk_get instead.
> 
> Signed-off-by: Hiago De Franco <hiago.franco@...adex.com>
> ---
>  drivers/remoteproc/imx_rproc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
> index 74299af1d7f1..45b5b23980ec 100644
> --- a/drivers/remoteproc/imx_rproc.c
> +++ b/drivers/remoteproc/imx_rproc.c
> @@ -1033,7 +1033,7 @@ static int imx_rproc_clk_enable(struct imx_rproc *priv)
>  	if (dcfg->method == IMX_RPROC_NONE)
>  		return 0;
>  
> -	priv->clk = devm_clk_get(dev, NULL);
> +	priv->clk = devm_clk_get_optional(dev, NULL);

If my understanding of the problem is correct (see above), I think the real fix
for this is to make the "clocks" property mandatory in the bindings.

Daniel and Iuliana, I'd like to have your opinions on this.

Thanks,
Mathieu

>  	if (IS_ERR(priv->clk)) {
>  		dev_err(dev, "Failed to get clock\n");
>  		return PTR_ERR(priv->clk);
> -- 
> 2.39.5
>