On Sun, Apr 14, 2019 at 07:27:47AM -0700, Guenter Roeck wrote:
>On 4/13/19 9:03 AM, Adamski, Krzysztof (Nokia - PL/Wroclaw) wrote:
>>Those virtual registers can be used to export manufacturer specific
>>functionality for controlling the number of samples for average values
>>reported by the device.
>>
>>Signed-off-by: Krzysztof Adamski <krzysztof.adamski@xxxxxxxxx>
>>---
>> Documentation/hwmon/sysfs-interface | 18 +++++
>> drivers/hwmon/pmbus/pmbus.h | 15 ++++
>> drivers/hwmon/pmbus/pmbus_core.c | 114 ++++++++++++++++++++++++++++
>> 3 files changed, 147 insertions(+)
>>
>>diff --git a/Documentation/hwmon/sysfs-interface b/Documentation/hwmon/sysfs-interface
>>index 2b9e1005d88b..7b91706d01c8 100644
>>--- a/Documentation/hwmon/sysfs-interface
>>+++ b/Documentation/hwmon/sysfs-interface
>>@@ -756,6 +756,24 @@ intrusion[0-*]_beep
>> 1: enable
>> RW
>>+********************************
>>+* Average sample configuration *
>>+********************************
>>+
>>+Devices allowing for reading {in,power,curr,temp}_average values may export
>>+attributes for controlling number of samples used to compute average.
>>+
>>+samples Sets number of average samples for all types of measurements.
>>+ RW
>>+
>>+in_samples
>>+power_samples
>>+curr_samples
>>+temp_samples Sets number of average samples for specific type of measurements.
>>+ Note that on some devices it won't be possible to set all of them
>>+ to different values so changing one might also change some others.
>>+ RW
>>+
>
>Separate patch for the above, please. Adding the ABI is one subject, adding support
>for it into a driver (or driver core) is another.
Sure, I'll do that.
>
>> sysfs attribute writes interpretation
>> -------------------------------------
>>diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
>>index 1d24397d36ec..e73289cc867d 100644
>>--- a/drivers/hwmon/pmbus/pmbus.h
>>+++ b/drivers/hwmon/pmbus/pmbus.h
>>@@ -217,6 +217,20 @@ enum pmbus_regs {
>> PMBUS_VIRT_PWM_ENABLE_2,
>> PMBUS_VIRT_PWM_ENABLE_3,
>> PMBUS_VIRT_PWM_ENABLE_4,
>>+
>>+ /* Samples for average
>>+ *
>>+ * Drivers wanting to expose functionality for changing the number of
>>+ * samples used for average values should implement support in
>>+ * {read,write}_word_data callback for either PMBUS_VIRT_SAMPLES if it
>>+ * applies to all types of measurements, or any number of specific
>>+ * PMBUS_VIRT_*_SAMPLES registers to allow for individual control.
>>+ */
>>+ PMBUS_VIRT_SAMPLES,
>>+ PMBUS_VIRT_IN_SAMPLES,
>>+ PMBUS_VIRT_CURR_SAMPLES,
>>+ PMBUS_VIRT_POWER_SAMPLES,
>>+ PMBUS_VIRT_TEMP_SAMPLES,
>> };
>> /*
>>@@ -371,6 +385,7 @@ enum pmbus_sensor_classes {
>> #define PMBUS_HAVE_STATUS_VMON BIT(19)
>> #define PMBUS_HAVE_PWM12 BIT(20)
>> #define PMBUS_HAVE_PWM34 BIT(21)
>>+#define PMBUS_HAVE_SAMPLES BIT(22)
>> #define PMBUS_PAGE_VIRTUAL BIT(31)
>>diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
>>index 2e2b5851139c..31b6bf49518c 100644
>>--- a/drivers/hwmon/pmbus/pmbus_core.c
>>+++ b/drivers/hwmon/pmbus/pmbus_core.c
>>@@ -1901,6 +1901,116 @@ static int pmbus_add_fan_attributes(struct i2c_client *client,
>> return 0;
>> }
>>+struct pmbus_samples_attr {
>>+ int reg;
>>+ char *name;
>>+};
>>+
>>+struct pmbus_samples_reg {
>>+ int page;
>>+ struct pmbus_samples_attr *attr;
>>+ struct device_attribute dev_attr;
>>+};
>>+
>>+static struct pmbus_samples_attr pmbus_samples_registers[] = {
>>+ {
>>+ .reg = PMBUS_VIRT_SAMPLES,
>>+ .name = "samples",
>>+ }, {
>>+ .reg = PMBUS_VIRT_IN_SAMPLES,
>>+ .name = "in_samples",
>>+ }, {
>>+ .reg = PMBUS_VIRT_CURR_SAMPLES,
>>+ .name = "curr_samples",
>>+ }, {
>>+ .reg = PMBUS_VIRT_POWER_SAMPLES,
>>+ .name = "power_samples",
>>+ }, {
>>+ .reg = PMBUS_VIRT_TEMP_SAMPLES,
>>+ .name = "temp_samples",
>>+ }
>>+};
>>+
>>+#define to_samples_reg(x) container_of(x, struct pmbus_samples_reg, dev_attr)
>>+
>>+static ssize_t pmbus_show_samples(struct device *dev,
>>+ struct device_attribute *devattr, char *buf)
>>+{
>>+ int val;
>>+ struct i2c_client *client = to_i2c_client(dev->parent);
>>+ struct pmbus_samples_reg *reg = to_samples_reg(devattr);
>>+
>>+ val = _pmbus_read_word_data(client, reg->page, reg->attr->reg);
>>+ if (val < 0)
>>+ return val;
>>+
>>+ return snprintf(buf, PAGE_SIZE, "%d\n", val);
>>+}
>>+
>>+static ssize_t pmbus_set_samples(struct device *dev,
>>+ struct device_attribute *devattr,
>>+ const char *buf, size_t count)
>>+{
>>+ int ret;
>>+ long val;
>>+ struct i2c_client *client = to_i2c_client(dev->parent);
>>+ struct pmbus_samples_reg *reg = to_samples_reg(devattr);
>>+
>>+ if (kstrtol(buf, 0, &val) < 0)
>>+ return -EINVAL;
>>+
>>+ ret = _pmbus_write_word_data(client, reg->page, reg->attr->reg, val);
>>+
>>+ return ret ? : count;
>>+}
>>+
>>+static int pmbus_add_samples_attr(struct pmbus_data *data, int page,
>>+ struct pmbus_samples_attr *attr)
>>+{
>>+ struct pmbus_samples_reg *reg;
>>+
>>+ reg = devm_kzalloc(data->dev, sizeof(*reg), GFP_KERNEL);
>>+ if (!reg)
>>+ return -ENOMEM;
>>+
>>+ reg->attr = attr;
>>+ reg->page = page;
>>+
>>+ pmbus_dev_attr_init(®->dev_attr, attr->name, (S_IWUSR | S_IRUGO),
>
>S_IWUSR ran out of favor and generates a checkpatch warning.
>Please use 0644.
I wasn't sure if its more important to care about checkpatch warning or
to keep convention in the file. I'll change to numerical value as
advised.
>
>>+ pmbus_show_samples, pmbus_set_samples);
>>+
>>+ return pmbus_add_attribute(data, ®->dev_attr.attr);
>>+}
>>+
>>+static int pmbus_add_samples_attributes(struct i2c_client *client,
>>+ struct pmbus_data *data)
>>+{
>>+ const struct pmbus_driver_info *info = data->info;
>>+ int page;
>>+
>>+ for (page = 0; page < info->pages; page++) {
>
>This won't work as intended on multi-page chips. If the driver writer
>is not careful, it will try to generate multiple similar attributes,
>one per page. I would suggest to only check this for page 0.
>At some point we may need to add a separate func pointer for
>chip specific attributes, but that should do for now.
>
Good point. I'll do that.
>>+ int s;:
>>+
>>+ if (!(info->func[page] & PMBUS_HAVE_SAMPLES))
>>+ continue;
>>+
>>+ for (s = 0; s < ARRAY_SIZE(pmbus_samples_registers); s++) {
>>+ int ret;
>>+ struct pmbus_samples_attr *attr;
>>+
>
>Please use reverse christmas tree here
>
> struct pmbus_samples_attr *attr;
> int ret;
Ok.
>>+ attr = &pmbus_samples_registers[s];
>>+ if (!pmbus_check_word_register(client, page, attr->reg))
>>+ continue;
>>+
>>+ ret = pmbus_add_samples_attr(data, page, attr);
>>+ if (ret)
>>+ return ret;
>>+ }
>>+ }
>>+
>>+ return 0;
>>+}
>>+
>> static int pmbus_find_attributes(struct i2c_client *client,
>> struct pmbus_data *data)
>> {
>>@@ -1932,6 +2042,10 @@ static int pmbus_find_attributes(struct i2c_client *client,
>> /* Fans */
>> ret = pmbus_add_fan_attributes(client, data);
>>+ if (ret)
>>+ return ret;
>>+
>>+ ret = pmbus_add_samples_attributes(client, data);
>> return ret;
>> }
>>
>
Krzysztof
