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

From: Guenter Roeck
Date: Sun Oct 25 2015 - 22:14:39 EST


On Mon, Oct 26, 2015 at 09:58:45AM +0800, Huang Rui wrote:
> On Fri, Oct 23, 2015 at 06:42:20AM -0700, Guenter Roeck wrote:
> > 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@xxxxxxxxx>
> > >Signed-off-by: Huang Rui <ray.huang@xxxxxxx>
> > >Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
> > >Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> > >Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> > >---
> > > 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.
> >
>
> That's because there will be a warning without the typecast.
>
> Expected 'const struct attribute_group **', but current type is 'const
> struct attribute_group * (*)[2]'.
>

Maybe then either use data->fam15h_power_groups (no &) or
&data->fam15h_power_groups[0].

On a side note, the "fam15h_" prefix in the variable name is really
unnecessary unless there are some other groups in the same data structure.
Even the "power_" prefix doesn't really add any value unless there
are other groups.

Thanks,
Guenter

> ---
> CC [M] /home/ray/tip/drivers/hwmon/fam15h_power.o
> /home/ray/tip/drivers/hwmon/fam15h_power.c: In function âfam15h_power_probeâ:
> /home/ray/tip/drivers/hwmon/fam15h_power.c:481:11: warning: passing argument 4 of âdevm_hwmon_device_register_with_groupsâ from incompatible pointer type [enabled by default]
> &data->fam15h_power_groups);
> ^
> In file included from /home/ray/tip/drivers/hwmon/fam15h_power.c:22:0:
> include/linux/hwmon.h:26:1: note: expected âconst struct attribute_group **â but argument is of type âconst struct attribute_group * (*)[2]â
> devm_hwmon_device_register_with_groups(struct device *dev, const char *name,
> ^
> ---
>
> Thanks,
> Rui
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