linux-kernel - RE: [PATCH V3] cpufreq: imx6q: read OCOTP through nvmem for imx6ul/imx6ull

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Message-ID: <DB3PR0402MB391676A53645F0E1C68BAA85F5E60@DB3PR0402MB3916.eurprd04.prod.outlook.com>
Date:   Mon, 8 Oct 2018 06:13:06 +0000
From:   Anson Huang <anson.huang@....com>
To:     Viresh Kumar <viresh.kumar@...aro.org>
CC:     "rjw@...ysocki.net" <rjw@...ysocki.net>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        dl-linux-imx <linux-imx@....com>
Subject: RE: [PATCH V3] cpufreq: imx6q: read OCOTP through nvmem for
 imx6ul/imx6ull

Hi, Viresh

Anson Huang
Best Regards!


> -----Original Message-----
> From: Viresh Kumar <viresh.kumar@...aro.org>
> Sent: Monday, October 8, 2018 2:04 PM
> To: Anson Huang <anson.huang@....com>
> Cc: rjw@...ysocki.net; linux-pm@...r.kernel.org;
> linux-kernel@...r.kernel.org; dl-linux-imx <linux-imx@....com>
> Subject: Re: [PATCH V3] cpufreq: imx6q: read OCOTP through nvmem for
> imx6ul/imx6ull
> 
> On 08-10-18, 09:10, Anson Huang wrote:
> > On i.MX6UL/i.MX6ULL, accessing OCOTP directly is wrong because the
> > ocotp clock needs to be enabled first. Add support for reading OCOTP
> > through the nvmem API, and keep the old method there to support old
> > dtb.
> >
> > Signed-off-by: Anson Huang <Anson.Huang@....com>
> > ---
> > changes since V2:
> > 	Add put node when reading ocotp register done.
> >  drivers/cpufreq/imx6q-cpufreq.c | 53
> > ++++++++++++++++++++++++++++-------------
> >  1 file changed, 36 insertions(+), 17 deletions(-)
> >
> > diff --git a/drivers/cpufreq/imx6q-cpufreq.c
> > b/drivers/cpufreq/imx6q-cpufreq.c index b2ff423..38b67f8 100644
> > --- a/drivers/cpufreq/imx6q-cpufreq.c
> > +++ b/drivers/cpufreq/imx6q-cpufreq.c
> > @@ -12,6 +12,7 @@
> >  #include <linux/cpu_cooling.h>
> >  #include <linux/err.h>
> >  #include <linux/module.h>
> > +#include <linux/nvmem-consumer.h>
> >  #include <linux/of.h>
> >  #include <linux/of_address.h>
> >  #include <linux/pm_opp.h>
> > @@ -290,20 +291,33 @@ static void
> imx6q_opp_check_speed_grading(struct device *dev)
> >  #define OCOTP_CFG3_6ULL_SPEED_792MHZ	0x2
> >  #define OCOTP_CFG3_6ULL_SPEED_900MHZ	0x3
> >
> > -static void imx6ul_opp_check_speed_grading(struct device *dev)
> > +static int imx6ul_opp_check_speed_grading(struct device *dev)
> >  {
> > -	struct device_node *np;
> > -	void __iomem *base;
> >  	u32 val;
> > +	int ret = 0;
> >
> > -	np = of_find_compatible_node(NULL, NULL, "fsl,imx6ul-ocotp");
> > -	if (!np)
> > -		return;
> > +	if (of_find_property(dev->of_node, "nvmem-cells", NULL)) {
> > +		ret = nvmem_cell_read_u32(dev, "speed_grade", &val);
> > +		if (ret)
> > +			return ret;
> > +	} else {
> > +		struct device_node *np;
> > +		void __iomem *base;
> > +
> > +		np = of_find_compatible_node(NULL, NULL, "fsl,imx6ul-ocotp");
> > +		if (!np)
> > +			return -ENOENT;
> > +
> > +		base = of_iomap(np, 0);
> 
> You could have done of_node_put(np); right here and remove the below two
> calls to the same.
 
Thanks for the suggestion, please help review V4.

Anson.

> 
> > +		if (!base) {
> > +			dev_err(dev, "failed to map ocotp\n");
> > +			of_node_put(np);
> > +			return -EFAULT;
> > +		}
> >
> > -	base = of_iomap(np, 0);
> > -	if (!base) {
> > -		dev_err(dev, "failed to map ocotp\n");
> > -		goto put_node;
> > +		val = readl_relaxed(base + OCOTP_CFG3);
> > +		iounmap(base);
> > +		of_node_put(np);
> >  	}
> 
> --
> viresh