linux-kernel - Re: [Patch v2 2/8] firmware: qcom: scm: Convert SCM to platform driver

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Message-ID: <20160429192554.GA6666@hector.attlocal.net>
Date:	Fri, 29 Apr 2016 14:25:54 -0500
From:	Andy Gross <andy.gross@...aro.org>
To:	Stephen Boyd <sboyd@...eaurora.org>
Cc:	linux-arm-msm@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org, jilai wang <jilaiw@...eaurora.org>
Subject: Re: [Patch v2 2/8] firmware: qcom: scm: Convert SCM to platform
 driver

On Mon, Apr 25, 2016 at 06:29:35PM -0700, Stephen Boyd wrote:
> On 04/25, Andy Gross wrote:
> > This patch converts the Qualcomm SCM firmware driver into a platform
> > driver.
> > 
> > Signed-off-by: Andy Gross <andy.gross@...aro.org>
> > ---
> >  arch/arm64/Kconfig.platforms |   1 +
> >  drivers/firmware/qcom_scm.c  | 163 ++++++++++++++++++++++++++++++++++++++++---
> >  2 files changed, 155 insertions(+), 9 deletions(-)
> > 
> > diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms
> > index efa77c1..6f0876f 100644
> > --- a/arch/arm64/Kconfig.platforms
> > +++ b/arch/arm64/Kconfig.platforms
> > @@ -76,6 +76,7 @@ config ARCH_MVEBU
> >  config ARCH_QCOM
> >  	bool "Qualcomm Platforms"
> >  	select PINCTRL
> > +	select QCOM_SCM
> 
> So far we've left this selection up to the consumer drivers of
> the qcom_scm_*() APIs. Any reason why that's changing here? I
> don't see mention in the commit text.

We can leave it that way.
> 
> >  	help
> >  	  This enables support for the ARMv8 based Qualcomm chipsets.
> >  
> > +
> > +/**
> > + * qcom_scm_is_available() - Checks if SCM is available
> > + */
> > +bool qcom_scm_is_available(void)
> > +{
> > +	return !!__scm;
> > +}
> > +EXPORT_SYMBOL(qcom_scm_is_available);
> 
> What's the planned user of this? If we need it can we bury it
> inside the qcom_scm_*() functions?

Hmmmm doing a little searching, I don't see this being used anymore.  I'll drop
it for now.

> > +
> > +static int qcom_scm_probe(struct platform_device *pdev)
> > +{
> [...]
> > +
> > +	/* vote for max clk rate for highest performance */
> > +	rate = clk_round_rate(scm->core_clk, INT_MAX);
> > +	ret = clk_set_rate(scm->core_clk, rate);
> 
> You can just do clk_set_rate(scm->core_clk, INT_MAX) and it will
> round internally for you and do the right thing. 

I'll change this to do that.

> > +	if (ret)
> > +		return ret;
> > +
> > +	__scm = scm;
> > +	__scm->dev = &pdev->dev;
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct of_device_id qcom_scm_dt_match[] = {
> > +	{ .compatible = "qcom,scm-apq8064",},
> > +	{ .compatible = "qcom,scm-apq8084",},
> > +	{ .compatible = "qcom,scm-msm8916",},
> > +	{ .compatible = "qcom,scm-msm8974",},
> > +	{},
> 
> Nitpick: drop , here because it's always going to be the last
> entry.

will fix.

> > +};
> > +
> > +MODULE_DEVICE_TABLE(of, qcom_scm_dt_match);
> > +
> > +static struct platform_driver qcom_scm_driver = {
> > +	.driver = {
> > +		.name	= "qcom_scm",
> > +		.of_match_table = qcom_scm_dt_match,
> > +	},
> > +	.probe = qcom_scm_probe,
> > +};
> > +
> > +builtin_platform_driver(qcom_scm_driver);
> > +
> > +static int __init qcom_scm_init(void)
> > +{
> > +	struct device_node *np;
> > +
> > +	np = of_find_node_by_name(NULL, "firmware");
> > +	if (!np)
> > +		return -ENODEV;
> > +
> > +	return of_platform_populate(np, qcom_scm_dt_match, NULL, NULL);
> > +
> 
> Weird newline and also we need an of_node_put() on the firmware
> node at the end of this function.

Ah thanks for catching that.


Regards,

Andy