linux-kernel - Re: [PATCH 02/18] spi: stm32-spi: defer probe for reset

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Date:   Fri, 7 Aug 2020 15:42:54 +0200
From:   Alain Volmat <alain.volmat@...com>
To:     Mark Brown <broonie@...nel.org>
CC:     <amelie.delaunay@...com>, <mcoquelin.stm32@...il.com>,
        <alexandre.torgue@...com>, <linux-spi@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <fabrice.gasnier@...com>
Subject: Re: [PATCH 02/18] spi: stm32-spi: defer probe for reset

On Wed, Aug 05, 2020 at 11:49:06AM +0100, Mark Brown wrote:
> On Wed, Aug 05, 2020 at 09:01:57AM +0200, Alain Volmat wrote:
> 
> > -	rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
> > -	if (!IS_ERR(rst)) {
> > +	rst = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);
> > +	if (rst) {
> > +		if (IS_ERR(rst)) {
> > +			ret = PTR_ERR(rst);
> > +			if (ret != -EPROBE_DEFER)
> > +				dev_err(&pdev->dev, "reset get failed: %d\n",
> > +					ret);
> > +			goto err_clk_disable;
> > +		}
> 
> This will not provide any diagnostics when deferring which isn't very
> helpful if there's issues.

Do you mean that a message when deferring would be needed ?

I am worrying that this would lead to having too much noise during boot
since probe deferring is kinda common. Of course it can also be due to a bad
configuration of the kernel as well but having looked around I think that
usually driver are rather silent in case of deferring.