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Date:   Sun, 13 Dec 2020 18:46:48 -0600
From:   Samuel Holland <samuel@...lland.org>
To:     Shuosheng Huang <huangshuosheng@...winnertech.com>,
        tiny.windzz@...il.com, rjw@...ysocki.net, viresh.kumar@...aro.org,
        mripard@...nel.org, wens@...e.org, jernej.skrabec@...l.net
Cc:     linux-pm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 1/6] cpufreq: sun50i: add efuse_xlate to get efuse
 version.

On 12/8/20 1:19 AM, Shuosheng Huang wrote:
> It's better to use efuse_xlate to extract the differentiated part
> regarding different SoC.
> 
> Signed-off-by: Shuosheng Huang <huangshuosheng@...winnertech.com>
> ---
>  drivers/cpufreq/sun50i-cpufreq-nvmem.c | 82 ++++++++++++++++----------
>  1 file changed, 51 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/cpufreq/sun50i-cpufreq-nvmem.c b/drivers/cpufreq/sun50i-cpufreq-nvmem.c
> index 9907a165135b..3c0531938d1a 100644
> --- a/drivers/cpufreq/sun50i-cpufreq-nvmem.c
> +++ b/drivers/cpufreq/sun50i-cpufreq-nvmem.c
> @@ -19,24 +19,51 @@
>  
>  #define MAX_NAME_LEN	7
>  
> -#define NVMEM_MASK	0x7
> -#define NVMEM_SHIFT	5
> +#define SUN50I_H6_NVMEM_MASK		0x7
> +#define SUN50I_H6_NVMEM_SHIFT		5
> +
> +struct sunxi_cpufreq_soc_data {
> +	int (*efuse_xlate)(struct nvmem_cell *speedbin_nvmem);
> +};
>  
>  static struct platform_device *cpufreq_dt_pdev, *sun50i_cpufreq_pdev;
>  
> +static int sun50i_h6_efuse_xlate(struct nvmem_cell *speedbin_nvmem)
> +{
> +	size_t len;
> +	u32 *speedbin;
> +	u32 efuse_value;
> +
> +	speedbin = nvmem_cell_read(speedbin_nvmem, &len);
> +	if (IS_ERR(speedbin))
> +		return PTR_ERR(speedbin);
> +
> +	efuse_value = (*(u32 *)speedbin >> SUN50I_H6_NVMEM_SHIFT) &
> +			  SUN50I_H6_NVMEM_MASK;

This does not need a cast. speedbin is already a pointer to u32.

With the cast removed:

Reviewed-by: Samuel Holland <samuel@...lland.org>
Tested-by: Samuel Holland <samuel@...lland.org> # H6

> +	kfree(speedbin);
> +	/*
> +	 * We treat unexpected efuse values as if the SoC was from
> +	 * the slowest bin. Expected efuse values are 1-3, slowest
> +	 * to fastest.
> +	 */
> +	if (efuse_value >= 1 && efuse_value <= 3)
> +		return efuse_value - 1;
> +	else
> +		return 0;
> +}
> +
>  /**
>   * sun50i_cpufreq_get_efuse() - Determine speed grade from efuse value
> - * @versions: Set to the value parsed from efuse
> + * @soc_data: pointer to sunxi_cpufreq_soc_data context
>   *
>   * Returns 0 if success.
>   */
> -static int sun50i_cpufreq_get_efuse(u32 *versions)
> +static int sun50i_cpufreq_get_efuse(const struct sunxi_cpufreq_soc_data *soc_data)
>  {
>  	struct nvmem_cell *speedbin_nvmem;
>  	struct device_node *np;
>  	struct device *cpu_dev;
> -	u32 *speedbin, efuse_value;
> -	size_t len;
> +	int versions;
>  	int ret;
>  
>  	cpu_dev = get_cpu_device(0);
> @@ -63,43 +90,33 @@ static int sun50i_cpufreq_get_efuse(u32 *versions)
>  		return PTR_ERR(speedbin_nvmem);
>  	}
>  
> -	speedbin = nvmem_cell_read(speedbin_nvmem, &len);
> +	versions = soc_data->efuse_xlate(speedbin_nvmem);
>  	nvmem_cell_put(speedbin_nvmem);
> -	if (IS_ERR(speedbin))
> -		return PTR_ERR(speedbin);
> -
> -	efuse_value = (*speedbin >> NVMEM_SHIFT) & NVMEM_MASK;
> -
> -	/*
> -	 * We treat unexpected efuse values as if the SoC was from
> -	 * the slowest bin. Expected efuse values are 1-3, slowest
> -	 * to fastest.
> -	 */
> -	if (efuse_value >= 1 && efuse_value <= 3)
> -		*versions = efuse_value - 1;
> -	else
> -		*versions = 0;
>  
> -	kfree(speedbin);
> -	return 0;
> +	return versions;
>  };
>  
>  static int sun50i_cpufreq_nvmem_probe(struct platform_device *pdev)
>  {
> +	const struct of_device_id *match;
>  	struct opp_table **opp_tables;
>  	char name[MAX_NAME_LEN];
>  	unsigned int cpu;
> -	u32 speed = 0;
> +	int speed = 0;
>  	int ret;
>  
> +	match = dev_get_platdata(&pdev->dev);
> +	if (!match)
> +		return -EINVAL;
> +
>  	opp_tables = kcalloc(num_possible_cpus(), sizeof(*opp_tables),
>  			     GFP_KERNEL);
>  	if (!opp_tables)
>  		return -ENOMEM;
>  
> -	ret = sun50i_cpufreq_get_efuse(&speed);
> -	if (ret)
> -		return ret;
> +	speed = sun50i_cpufreq_get_efuse(match->data);
> +	if (speed < 0)
> +		return speed;
>  
>  	snprintf(name, MAX_NAME_LEN, "speed%d", speed);
>  
> @@ -163,8 +180,12 @@ static struct platform_driver sun50i_cpufreq_driver = {
>  	},
>  };
>  
> +static const struct sunxi_cpufreq_soc_data sun50i_h6_data = {
> +	.efuse_xlate = sun50i_h6_efuse_xlate,
> +};
> +
>  static const struct of_device_id sun50i_cpufreq_match_list[] = {
> -	{ .compatible = "allwinner,sun50i-h6" },
> +	{ .compatible = "allwinner,sun50i-h6", .data = &sun50i_h6_data },
>  	{}
>  };
>  
> @@ -198,9 +219,8 @@ static int __init sun50i_cpufreq_init(void)
>  	if (unlikely(ret < 0))
>  		return ret;
>  
> -	sun50i_cpufreq_pdev =
> -		platform_device_register_simple("sun50i-cpufreq-nvmem",
> -						-1, NULL, 0);
> +	sun50i_cpufreq_pdev = platform_device_register_data(NULL,
> +		"sun50i-cpufreq-nvmem", -1, match, sizeof(*match));
>  	ret = PTR_ERR_OR_ZERO(sun50i_cpufreq_pdev);
>  	if (ret == 0)
>  		return 0;
> 

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