linux-kernel - Re: [PATCH V4] cpufreq: imx6q: read OCOTP through nvmem for imx6ul/imx6ull

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Message-ID: <20181008061508.m3u7acg2q76jljay@vireshk-i7>
Date:   Mon, 8 Oct 2018 11:45:08 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Anson Huang <Anson.Huang@....com>
Cc:     rjw@...ysocki.net, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Linux-imx@....com
Subject: Re: [PATCH V4] cpufreq: imx6q: read OCOTP through nvmem for
 imx6ul/imx6ull

On 08-10-18, 14:07, 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 V3:
> 	put node earlier to save one line code.
>  drivers/cpufreq/imx6q-cpufreq.c | 52 +++++++++++++++++++++++++++--------------
>  1 file changed, 35 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c
> index b2ff423..8cfee0a 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 +291,32 @@ 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);
> +		of_node_put(np);
> +		if (!base) {
> +			dev_err(dev, "failed to map ocotp\n");
> +			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);
>  	}
>  
>  	/*
> @@ -314,7 +327,6 @@ static void imx6ul_opp_check_speed_grading(struct device *dev)
>  	 * 2b'11: 900000000Hz on i.MX6ULL only;
>  	 * We need to set the max speed of ARM according to fuse map.
>  	 */
> -	val = readl_relaxed(base + OCOTP_CFG3);
>  	val >>= OCOTP_CFG3_SPEED_SHIFT;
>  	val &= 0x3;
>  
> @@ -334,9 +346,7 @@ static void imx6ul_opp_check_speed_grading(struct device *dev)
>  				dev_warn(dev, "failed to disable 900MHz OPP\n");
>  	}
>  
> -	iounmap(base);
> -put_node:
> -	of_node_put(np);
> +	return ret;
>  }
>  
>  static int imx6q_cpufreq_probe(struct platform_device *pdev)
> @@ -394,10 +404,18 @@ static int imx6q_cpufreq_probe(struct platform_device *pdev)
>  	}
>  
>  	if (of_machine_is_compatible("fsl,imx6ul") ||
> -	    of_machine_is_compatible("fsl,imx6ull"))
> -		imx6ul_opp_check_speed_grading(cpu_dev);
> -	else
> +	    of_machine_is_compatible("fsl,imx6ull")) {
> +		ret = imx6ul_opp_check_speed_grading(cpu_dev);
> +		if (ret == -EPROBE_DEFER)
> +			return ret;
> +		if (ret) {
> +			dev_err(cpu_dev, "failed to read ocotp: %d\n",
> +				ret);
> +			return ret;
> +		}
> +	} else {
>  		imx6q_opp_check_speed_grading(cpu_dev);
> +	}
>  
>  	/* Because we have added the OPPs here, we must free them */
>  	free_opp = true;

Acked-by: Viresh Kumar <viresh.kumar@...aro.org>

-- 
viresh