Re: [PATCH 2/3] cpufreq: ti-cpufreq: Support nvmem for chip version

[Dhruva Gole]

Hi,

On Feb 06, 2024 at 15:57:20 +0100, Markus Schneider-Pargmann wrote:
> Support using nvmem-cells 'chipvariant' and 'chipspeed' instead of
> syscon. This makes it more flexible and moves more configuration into
> the devicetree.
> 
> If nvmem-cells are present, probing will fail if the configuration of
> these cells is broken. If nvmem-cells is not present syscon will be
> used.
> 
> Signed-off-by: Markus Schneider-Pargmann <msp@xxxxxxxxxxxx>
> ---
>  drivers/cpufreq/ti-cpufreq.c | 105 ++++++++++++++++++++++-------------
>  1 file changed, 66 insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/cpufreq/ti-cpufreq.c b/drivers/cpufreq/ti-cpufreq.c
> index 46c41e2ca727..3ee72b1309f0 100644
> --- a/drivers/cpufreq/ti-cpufreq.c
> +++ b/drivers/cpufreq/ti-cpufreq.c
> @@ -10,6 +10,7 @@
>  #include <linux/io.h>
>  #include <linux/mfd/syscon.h>
>  #include <linux/module.h>
> +#include <linux/nvmem-consumer.h>
>  #include <linux/init.h>
>  #include <linux/of.h>
>  #include <linux/platform_device.h>
> @@ -65,6 +66,7 @@ struct ti_cpufreq_soc_data {
>  
>  struct ti_cpufreq_data {
>  	struct device *cpu_dev;
> +	struct device *dev;
>  	struct device_node *opp_node;
>  	struct regmap *syscon;
>  	const struct ti_cpufreq_soc_data *soc_data;
> @@ -244,31 +246,40 @@ static struct ti_cpufreq_soc_data am625_soc_data = {
>  static int ti_cpufreq_get_efuse(struct ti_cpufreq_data *opp_data,
>  				u32 *efuse_value)
>  {
> +	struct device_node *np = opp_data->opp_node;

Umm.. slightly confused, where is *np being used?

>  	struct device *dev = opp_data->cpu_dev;
>  	u32 efuse;
>  	int ret;
>  
> -	ret = regmap_read(opp_data->syscon, opp_data->soc_data->efuse_offset,
> -			  &efuse);
> -	if (ret == -EIO) {
> -		/* not a syscon register! */
> -		void __iomem *regs = ioremap(OMAP3_SYSCON_BASE +
> -				opp_data->soc_data->efuse_offset, 4);
> -
> -		if (!regs)
> -			return -ENOMEM;
> -		efuse = readl(regs);
> -		iounmap(regs);
> +	ret = nvmem_cell_read_u32(opp_data->dev, "chipspeed", &efuse);
> +	if (ret && (ret != -ENOENT || !opp_data->syscon))
> +		return dev_err_probe(dev, ret,
> +				     "Failed to read nvmem cell 'chipspeed': %pe",
> +				     ERR_PTR(ret));
> +
> +	if (ret) {
> +		ret = regmap_read(opp_data->syscon, opp_data->soc_data->efuse_offset,
> +				  &efuse);
> +		if (ret == -EIO) {
> +			/* not a syscon register! */
> +			void __iomem *regs = ioremap(OMAP3_SYSCON_BASE +
> +					opp_data->soc_data->efuse_offset, 4);
> +
> +			if (!regs)
> +				return -ENOMEM;
> +			efuse = readl(regs);
> +			iounmap(regs);
> +			}
> +		else if (ret) {

else should be enough I guess, no need of elif?

> +			dev_err(dev,
> +				"Failed to read the efuse value from syscon: %d\n",
> +				ret);
> +			return ret;
>  		}
> -	else if (ret) {
> -		dev_err(dev,
> -			"Failed to read the efuse value from syscon: %d\n",
> -			ret);
> -		return ret;
> -	}
>  
> -	efuse = (efuse & opp_data->soc_data->efuse_mask);
> -	efuse >>= opp_data->soc_data->efuse_shift;
> +		efuse = (efuse & opp_data->soc_data->efuse_mask);
> +		efuse >>= opp_data->soc_data->efuse_shift;
> +	}
>  
>  	*efuse_value = opp_data->soc_data->efuse_xlate(opp_data, efuse);
>  
> @@ -285,30 +296,41 @@ static int ti_cpufreq_get_efuse(struct ti_cpufreq_data *opp_data,
>  static int ti_cpufreq_get_rev(struct ti_cpufreq_data *opp_data,
>  			      u32 *revision_value)
>  {
> +	struct device_node *np = opp_data->opp_node;

where is this used? Atleast, in this patch I don't see it...

>  	struct device *dev = opp_data->cpu_dev;
>  	u32 revision;
>  	int ret;
>  
> -	ret = regmap_read(opp_data->syscon, opp_data->soc_data->rev_offset,
> -			  &revision);
> -	if (ret == -EIO) {
> -		/* not a syscon register! */
> -		void __iomem *regs = ioremap(OMAP3_SYSCON_BASE +
> -				opp_data->soc_data->rev_offset, 4);
> -
> -		if (!regs)
> -			return -ENOMEM;
> -		revision = readl(regs);
> -		iounmap(regs);
> +	ret = nvmem_cell_read_u32(opp_data->dev, "chipvariant", &revision);
> +	if (ret && (ret != -ENOENT || !opp_data->syscon))
> +		return dev_err_probe(dev, ret,
> +				     "Failed to read nvmem cell 'chipvariant': %pe",
> +				     ERR_PTR(ret));
> +
> +	if (ret) {
> +		ret = regmap_read(opp_data->syscon, opp_data->soc_data->rev_offset,
> +				  &revision);
> +		if (ret == -EIO) {
> +			/* not a syscon register! */
> +			void __iomem *regs = ioremap(OMAP3_SYSCON_BASE +
> +					opp_data->soc_data->rev_offset, 4);
> +
> +			if (!regs)
> +				return -ENOMEM;
> +			revision = readl(regs);
> +			iounmap(regs);
> +			}
> +		else if (ret) {

Do you really have to? This code will reach only if(ret) is satisfied,
the elif feels redundant. Else should be fine

> +			dev_err(dev,
> +				"Failed to read the revision number from syscon: %d\n",
> +				ret);
> +			return ret;
>  		}
> -	else if (ret) {
> -		dev_err(dev,
> -			"Failed to read the revision number from syscon: %d\n",
> -			ret);
> -		return ret;
> +
> +		revision = (revision >> REVISION_SHIFT) & REVISION_MASK;
>  	}
>  
> -	*revision_value = BIT((revision >> REVISION_SHIFT) & REVISION_MASK);
> +	*revision_value = BIT(revision);
>  
>  	return 0;
>  }
> @@ -392,9 +414,14 @@ static int ti_cpufreq_probe(struct platform_device *pdev)
>  		goto register_cpufreq_dt;
>  	}
>  
> -	ret = ti_cpufreq_setup_syscon_register(opp_data);
> -	if (ret)
> -		goto fail_put_node;
> +	opp_data->dev = &pdev->dev;
> +	opp_data->dev->of_node = opp_data->opp_node;
> +
> +	if (!of_property_read_bool(opp_data->opp_node, "nvmem-cells")) {
> +		ret = ti_cpufreq_setup_syscon_register(opp_data);
> +		if (ret)
> +			goto fail_put_node;
> +	}

Mostly looks okay, with above comments addressed:

Reviewed-by: Dhruva Gole <d-gole@xxxxxx>

-- 
Best regards,
Dhruva Gole <d-gole@xxxxxx>