Re: [PATCH v2 01/10] hwmon: (fam15h_power) Refactor attributes for dynamically added

[Guenter Roeck <linux@roeck-us.net>]

On 10/19/2015 07:28 PM, Huang Rui wrote:
> Attributes depend on the CPU model the driver gets loaded on.
> Therefore, add those attributes dynamically at init time. This is more
> flexible to control the different attributes on different platforms.
>
> Suggestedy-by: Borislav Petkov <bp@alien8.de>
> Signed-off-by: Huang Rui <ray.huang@amd.com>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@kernel.org>
> ---
>   drivers/hwmon/fam15h_power.c | 70 ++++++++++++++++++++++++++++----------------
>   1 file changed, 45 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/hwmon/fam15h_power.c b/drivers/hwmon/fam15h_power.c
> index e80ee23..41d022e 100644
> --- a/drivers/hwmon/fam15h_power.c
> +++ b/drivers/hwmon/fam15h_power.c
> @@ -41,12 +41,17 @@ MODULE_LICENSE("GPL");
>   #define REG_TDP_RUNNING_AVERAGE		0xe0
>   #define REG_TDP_LIMIT3			0xe8
>
> +#define FAM15H_MIN_NUM_ATTRS		2
> +#define FAM15H_NUM_GROUPS		2
> +
>   struct fam15h_power_data {
>   	struct pci_dev *pdev;
>   	unsigned int tdp_to_watts;
>   	unsigned int base_tdp;
>   	unsigned int processor_pwr_watts;
>   	unsigned int cpu_pwr_sample_ratio;
> +	const struct attribute_group *fam15h_power_groups[FAM15H_NUM_GROUPS];
> +	struct attribute_group fam15h_power_group;
>   };
>
>   static ssize_t show_power(struct device *dev,
> @@ -105,29 +110,31 @@ static ssize_t show_power_crit(struct device *dev,
>   }
>   static DEVICE_ATTR(power1_crit, S_IRUGO, show_power_crit, NULL);
>
> -static umode_t fam15h_power_is_visible(struct kobject *kobj,
> -				       struct attribute *attr,
> -				       int index)
> +static int fam15h_power_init_attrs(struct pci_dev *pdev,
> +				   struct fam15h_power_data *data)
>   {
> -	/* power1_input is only reported for Fam15h, Models 00h-0fh */
> -	if (attr == &dev_attr_power1_input.attr &&
> -	   (boot_cpu_data.x86 != 0x15 || boot_cpu_data.x86_model > 0xf))
> -		return 0;
> +	int n = FAM15H_MIN_NUM_ATTRS;
> +	struct attribute **fam15h_power_attrs;
>
> -	return attr->mode;
> -}
> +	if (boot_cpu_data.x86 == 0x15 && boot_cpu_data.x86_model <= 0xf)
> +		n += 1;
>
> -static struct attribute *fam15h_power_attrs[] = {
> -	&dev_attr_power1_input.attr,
> -	&dev_attr_power1_crit.attr,
> -	NULL
> -};
> +	fam15h_power_attrs = devm_kcalloc(&pdev->dev, n,
> +					  sizeof(*fam15h_power_attrs),
> +					  GFP_KERNEL);
>
> -static const struct attribute_group fam15h_power_group = {
> -	.attrs = fam15h_power_attrs,
> -	.is_visible = fam15h_power_is_visible,
> -};
> -__ATTRIBUTE_GROUPS(fam15h_power);
> +	if (!fam15h_power_attrs)
> +		return -ENOMEM;
> +
> +	n = 0;
> +	fam15h_power_attrs[n++] = &dev_attr_power1_crit.attr;
> +	if (boot_cpu_data.x86 == 0x15 && boot_cpu_data.x86_model <= 0xf)
> +		fam15h_power_attrs[n++] = &dev_attr_power1_input.attr;
> +
> +	data->fam15h_power_group.attrs = fam15h_power_attrs;
> +
> +	return 0;
> +}
>
>   static bool should_load_on_this_node(struct pci_dev *f4)
>   {
> @@ -186,11 +193,12 @@ static int fam15h_power_resume(struct pci_dev *pdev)
>   #define fam15h_power_resume NULL
>   #endif
>
> -static void fam15h_power_init_data(struct pci_dev *f4,
> -					     struct fam15h_power_data *data)
> +static int fam15h_power_init_data(struct pci_dev *f4,
> +				  struct fam15h_power_data *data)
>   {
>   	u32 val, eax, ebx, ecx, edx;
>   	u64 tmp;
> +	int ret;
>
>   	pci_read_config_dword(f4, REG_PROCESSOR_TDP, &val);
>   	data->base_tdp = val >> 16;
> @@ -211,11 +219,15 @@ static void fam15h_power_init_data(struct pci_dev *f4,
>   	/* convert to microWatt */
>   	data->processor_pwr_watts = (tmp * 15625) >> 10;
>
> +	ret = fam15h_power_init_attrs(f4, data);
> +	if (ret)
> +		return ret;
> +
>   	cpuid(0x80000007, &eax, &ebx, &ecx, &edx);
>
>   	/* CPUID Fn8000_0007:EDX[12] indicates to support accumulated power */
>   	if (!(edx & BIT(12)))
> -		return;
> +		return 0;
>
>   	/*
>   	 * determine the ratio of the compute unit power accumulator
> @@ -223,14 +235,17 @@ static void fam15h_power_init_data(struct pci_dev *f4,
>   	 * Fn8000_0007:ECX
>   	 */
>   	data->cpu_pwr_sample_ratio = ecx;
> +
> +	return 0;
>   }
>
>   static int fam15h_power_probe(struct pci_dev *pdev,
> -					const struct pci_device_id *id)
> +			      const struct pci_device_id *id)
>   {
>   	struct fam15h_power_data *data;
>   	struct device *dev = &pdev->dev;
>   	struct device *hwmon_dev;
> +	int ret;
>
>   	/*
>   	 * though we ignore every other northbridge, we still have to
> @@ -246,12 +261,17 @@ static int fam15h_power_probe(struct pci_dev *pdev,
>   	if (!data)
>   		return -ENOMEM;
>
> -	fam15h_power_init_data(pdev, data);
> +	ret = fam15h_power_init_data(pdev, data);
> +	if (ret)
> +		return ret;
> +
>   	data->pdev = pdev;
>
> +	data->fam15h_power_groups[0] = &data->fam15h_power_group;
> +
>   	hwmon_dev = devm_hwmon_device_register_with_groups(dev, "fam15h_power",
>   							   data,
> -							   fam15h_power_groups);
> +							   (const struct attribute_group **)&data->fam15h_power_groups);

Why this typecast ? It should not be needed.

Guenter