Messages in this thread Patch in this message | | | Subject | Re: [RFC PATCH 2/4] pmbus: Add fan configuration support | From | Guenter Roeck <> | Date | Tue, 11 Jul 2017 20:43:21 -0700 |
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On 07/11/2017 05:39 PM, Andrew Jeffery wrote: > On Tue, 2017-07-11 at 06:40 -0700, Guenter Roeck wrote: >> On 07/10/2017 06:56 AM, Andrew Jeffery wrote: >>> Augment PMBus support to include control of fans via the >>> FAN_COMMAND_[1-4] registers, both in RPM and PWM modes. The behaviour >>> of FAN_CONFIG_{1_2,3_4} and FAN_COMMAND_[1-4] are tightly coupled, and >>> their interactions do not fit the existing use of struct pmbus_sensor. >>> The patch introduces struct pmbus_fan_ctrl to distinguish from the >>> simple sensor case, along with associated sysfs show/set implementations. >>> >>> Further, the interpreting the value of FAN_COMMAND_[1-4] depends on both >>> the current fan mode (RPM or PWM, as configured in >>> FAN_CONFIG_{1_2,3_4}), and the device-specific behaviour for the >>> register. For example, the MAX31785 chip defines the following: >>> >>> PWM (m = 1, b = 0, R = 2): >>> 0x0000 - 0x2710: 0 - 100% fan PWM duty cycle >>> 0x2711 - 0x7fff: 100% fan PWM duty cycle >>> 0x8000 - 0xffff: Ignore FAN_COMMAND_[1-4], use automatic fan control >>> >>> RPM (m = 1, b = 0, R = 0): >>> 0x0000 - 0x7FFF: 0 - 32,767 RPM >>> 0x8000 - 0xFFFF: Ignore FAN_COMMAND_[1-4], use automatic fan control >>> >>> To handle the device-specific interpretation of the FAN_COMMAND_[1-4], >>> add an optional callbacks to the info struct to get/set the 'mode' >>> value required for the pwm[1-n]_enable sysfs attribute. A fallback >>> calculation exists if the callbacks are not populated; the fallback >>> ignores device-specific ranges and tries to determine a reasonable value >>> from FAN_CONFIG_{1_2,3_4} and FAN_COMMAND_[1-4]. >>> >> >> This seems overly complex, but unfortunately I don't have time for a detailed >> analysis right now. > > No worries. It turned out more complex than I was hoping as well, and I > am keen to hear any insights to trim it down. > >> Couple of comments below. > > Yep, thanks for taking a look. > >> >> Guenter >> >>>>> Signed-off-by: Andrew Jeffery <andrew@aj.id.au> >>> --- >>> drivers/hwmon/pmbus/pmbus.h | 7 + >>> drivers/hwmon/pmbus/pmbus_core.c | 335 +++++++++++++++++++++++++++++++++++++++ >>> 2 files changed, 342 insertions(+) >>> >>> diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h >>> index bfcb13bae34b..927eabc1b273 100644 >>> --- a/drivers/hwmon/pmbus/pmbus.h >>> +++ b/drivers/hwmon/pmbus/pmbus.h >>> @@ -223,6 +223,8 @@ enum pmbus_regs { >>>>> #define PB_FAN_1_RPM BIT(6) >>>>> #define PB_FAN_1_INSTALLED BIT(7) >>> >>> +enum pmbus_fan_mode { percent = 0, rpm }; >>> + >>> /* >>> * STATUS_BYTE, STATUS_WORD (lower) >>> */ >>> @@ -380,6 +382,11 @@ struct pmbus_driver_info { >>>>> int (*identify)(struct i2c_client *client, >>>>> struct pmbus_driver_info *info); >>> >>>>> + /* Allow the driver to interpret the fan command value */ >>>>> + int (*get_pwm_mode)(int id, u8 fan_config, u16 fan_command); >>>>> + int (*set_pwm_mode)(int id, long mode, u8 *fan_config, >>>>> + u16 *fan_command); >>> + >> >> It is not entirely obvious to me why this would require new callback functions. >> Can you overload PMBUS_FAN_CONFIG_12 / PMBUS_FAN_CONFIG_34 or, if that does not >> work for some reason, introduce a virtual register, such as PMBUS_VIRT_PWM_MODE ? > > Can you expand on the thought of overloading PMBUS_FAN_CONFIG_{12,34}? >
Every register/command can be implemented in the front end driver in its read/write functions. For example, see max34440_read_byte_data(), which replaces some of the status registers. ucd9000.c actually overrides PMBUS_FAN_CONFIG_12 and PMBUS_FAN_CONFIG_34.
> Regarding virtual registers, I saw references to them whilst I was > working my way through the core code but didn't stop to investigate. > I'll take a deeper look. > Virtual registers/commands are meant to "standardize" non-standard PMBus commands.
For example, PMBus provides no means to read the average/minimum/maximum temperature. Modeling the respective attributes using PMBUS_VIRT_READ_TEMP_AVG, PMBUS_VIRT_READ_TEMP_MIN, and PMBUS_VIRT_READ_TEMP_MAX, and providing driver-specific read/write functions which map the virtual commands to real chip registers makes the code much simpler than per-attribute callbacks. With virtual commands, the core only needs entries such as
}, { .reg = PMBUS_VIRT_READ_TEMP_MIN, .attr = "lowest", }, { .reg = PMBUS_VIRT_READ_TEMP_AVG, .attr = "average", }, { .reg = PMBUS_VIRT_READ_TEMP_MAX, .attr = "highest",
to support such non-standard attributes. Imagine how that would look like if each of the supported virtual commands would be implemented as callback.
> However, the addition of the callbacks was driven by the behaviour of > the MAX31785, where some values written to PMBUS_FAN_COMMAND_1 trigger > automated control, while others retain manual control. Patch 4/4 should > provide a bit more context, though I've also outlined the behaviour in > the commit message for this patch. I don't have a lot of experience > with PMBus devices so I don't have a good idea if there's a better way > to capture the behaviour that isn't so unconstrained in its approach. >
Many pmbus commands have side effects. I don't see how an explicit callback would be different to overloading a standard register or to providing a virtual register/command, whichever is more convenient.
>> >>>>> /* Regulator functionality, if supported by this chip driver. */ >>>>> int num_regulators; >>>>> const struct regulator_desc *reg_desc; >>> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c >>> index ba59eaef2e07..3b0a55bbbd2c 100644 >>> --- a/drivers/hwmon/pmbus/pmbus_core.c >>> +++ b/drivers/hwmon/pmbus/pmbus_core.c >>> @@ -69,6 +69,38 @@ struct pmbus_sensor { >>> #define to_pmbus_sensor(_attr) \ >>>>> container_of(_attr, struct pmbus_sensor, attribute) >>> >>>>> +#define PB_FAN_CONFIG_RPM PB_FAN_2_RPM >>> +#define PB_FAN_CONFIG_INSTALLED PB_FAN_2_INSTALLEDBUS_VIRT_ >> >> Something seems odd here. PB_FAN_2_INSTALLEDBUS_VIRT_ ? > > Yes, that's busted. Not sure what went wrong, but I'll clean it up. > >> >>>>> +#define PB_FAN_CONFIG_MASK(i) (0xff << (4 * !((i) & 1))) >>>>> +#define PB_FAN_CONFIG_GET(i, n) (((n) >> (4 * !((i) & 1))) & 0xff) >>>>> +#define PB_FAN_CONFIG_PUT(i, n) (((n) & 0xff) << (4 * !((i) & 1))) >>> + >> >> Aren't there standard bit manipulation macros for that ? Either case, this is just to avoid >> having to use the existing defines. > > As I store the configuration for each fan in a struct pmbus_fan_ctrl > dedicated to the fan, I reasoned that intermediate code should not have
I rather wonder if pmbus_fan_ctrl is needed in the first place. The notion of local 'struct pmbus_sensor' variables seems really messy. I think I'll really have to spend some time on this to see if and how it can be simplified; it just should not be that complex.
Thanks, Guenter
> to deal with the details of which nibble to access with respect to the > fan's (per-page) ID. Rather, code reading or writing > PMBUS_FAN_COMMAND_[1-4] should deal with ensuring the correct values > are provided. > >> Ok, but then I think it would make more sense to >> make it generic, ie change the core to not use PB_FAN_2_RPM / PB_FAN_1_RPM etc. >> but PB_FAN_RPM(index) everywhere. > > I'll make the change throughout pmbus core. > >> >>> +struct pmbus_fan_ctrl_attr { >>>>> + struct device_attribute attribute; >>>>> + char name[PMBUS_NAME_SIZE]; >>> +}; >>> + >>> +struct pmbus_fan_ctrl { >>>>> + struct pmbus_fan_ctrl_attr fan_target; >>>>> + struct pmbus_fan_ctrl_attr pwm; >>>>> + struct pmbus_fan_ctrl_attr pwm_enable; >>>>> + int index; >>>>> + u8 page; >>>>> + u8 id; >>>>> + u8 config; >>>>> + u16 command; >>> +}; >>> +#define to_pmbus_fan_ctrl_attr(_attr) \ >>>>> + container_of(_attr, struct pmbus_fan_ctrl_attr, attribute) >>> +#define fan_target_to_pmbus_fan_ctrl(_attr) \ >>>>> + container_of(to_pmbus_fan_ctrl_attr(_attr), struct pmbus_fan_ctrl, \ >>>>> + fan_target) >>> +#define pwm_to_pmbus_fan_ctrl(_attr) \ >>>>> + container_of(to_pmbus_fan_ctrl_attr(_attr), struct pmbus_fan_ctrl, pwm) >>> +#define pwm_enable_to_pmbus_fan_ctrl(_attr) \ >>>>> + container_of(to_pmbus_fan_ctrl_attr(_attr), struct pmbus_fan_ctrl, \ >>>>> + pwm_enable) >>> + >>> struct pmbus_boolean { >>>>>>> char name[PMBUS_NAME_SIZE]; /* sysfs boolean name */ >>>>> struct sensor_device_attribute attribute; >>> @@ -806,6 +838,219 @@ static ssize_t pmbus_show_label(struct device *dev, >>>>> return snprintf(buf, PAGE_SIZE, "%s\n", label->label); >>> } >>> >>> +static ssize_t pmbus_show_fan_command(struct device *dev, >>>>> + enum pmbus_fan_mode mode, >>>>> + struct pmbus_fan_ctrl *fan, char *buf) >>> +{ >>>>> + struct i2c_client *client = to_i2c_client(dev->parent); >>>>> + struct pmbus_data *data = i2c_get_clientdata(client); >>>>> + struct pmbus_sensor sensor; >>>>> + long val; >>> + >>>>> + mutex_lock(&data->update_lock); >>> + >>>>> + if ((mode == percent && (fan->config & PB_FAN_CONFIG_RPM)) || >>>>> + (mode == rpm && !(fan->config & PB_FAN_CONFIG_RPM))) { >>>>> + mutex_unlock(&data->update_lock); >>> + return -ENOTSUPP; /* XXX: This seems dodgy, but what to do? */ >> >> Not create the attribute in question in the first place, or return 0. The above >> messes up the 'sensors' command. > > I think returning 0 is the only valid option of the two, given that we > can dynamically switch between RPM and PWM modes. > > Thanks for the feedback. > > Andrew > >> >>>>> + } >>> + >>>>> + sensor.class = PSC_FAN; >>>>> + if (mode == percent) >>>>> + sensor.data = fan->command * 255 / 100; >>>>> + else >>>>> + sensor.data = fan->command; >>> + >>>>> + val = pmbus_reg2data(data, &sensor); >>> + >>>>> + mutex_unlock(&data->update_lock); >>> + >>>>> + return snprintf(buf, PAGE_SIZE, "%ld\n", val); >>> +} >>> + >>> +static ssize_t pmbus_show_fan_target(struct device *dev, >>>>> + struct device_attribute *da, char *buf) >>> +{ >>>>> + return pmbus_show_fan_command(dev, rpm, >>>>> + fan_target_to_pmbus_fan_ctrl(da), buf); >>> +} >>> + >>> +static ssize_t pmbus_show_pwm(struct device *dev, >>>>> + struct device_attribute *da, char *buf) >>> +{ >>>>> + return pmbus_show_fan_command(dev, percent, pwm_to_pmbus_fan_ctrl(da), >>>>> + buf); >>> +} >>> + >>> +static ssize_t pmbus_set_fan_command(struct device *dev, >>>>> + enum pmbus_fan_mode mode, >>>>> + struct pmbus_fan_ctrl *fan, >>>>> + const char *buf, ssize_t count) >>> +{ >>>>> + struct i2c_client *client = to_i2c_client(dev->parent); >>>>> + struct pmbus_data *data = i2c_get_clientdata(client); >>>>> + int config_addr, command_addr; >>>>> + struct pmbus_sensor sensor; >>>>> + ssize_t rv; >>>>> + long val; >>> + >>>>> + if (kstrtol(buf, 10, &val) < 0) >>>>> + return -EINVAL; >>> + >>>>> + mutex_lock(&data->update_lock); >>> + >>>>> + sensor.class = PSC_FAN; >>> + >>>>> + val = pmbus_data2reg(data, &sensor, val); >>> + >>>>> + if (mode == percent) >>>>> + val = val * 100 / 255; >>> + >>>>> + config_addr = (fan->id < 2) ? PMBUS_FAN_CONFIG_12 : PMBUS_FAN_CONFIG_34; >>>>> + command_addr = config_addr + 1 + (fan->id & 1); >>> + >>>>> + if (mode == rpm) >>>>> + fan->config |= PB_FAN_CONFIG_RPM; >>>>> + else >>>>> + fan->config &= ~PB_FAN_CONFIG_RPM; >>> + >>>>> + rv = pmbus_update_byte_data(client, fan->page, config_addr, >>>>> + PB_FAN_CONFIG_PUT(fan->id, fan->config), >>>>> + PB_FAN_CONFIG_MASK(fan->id)); >>>>> + if (rv < 0) >>>>> + goto done; >>> + >>>>> + fan->command = val; >>>>> + rv = pmbus_write_word_data(client, fan->page, command_addr, >>>>> + fan->command); >>> + >>> +done: >>>>> + mutex_unlock(&data->update_lock); >>> + >>>>> + if (rv < 0) >>>>> + return rv; >>> + >>>>> + return count; >>> +} >>> + >>> +static ssize_t pmbus_set_fan_target(struct device *dev, >>>>> + struct device_attribute *da, >>>>> + const char *buf, size_t count) >>> +{ >>>>> + return pmbus_set_fan_command(dev, rpm, >>>>> + fan_target_to_pmbus_fan_ctrl(da), buf, >>>>> + count); >>> +} >>> + >>> +static ssize_t pmbus_set_pwm(struct device *dev, struct device_attribute *da, >>>>> + const char *buf, size_t count) >>> +{ >>>>> + return pmbus_set_fan_command(dev, percent, pwm_to_pmbus_fan_ctrl(da), >>>>> + buf, count); >>> +} >>> + >>> +static ssize_t pmbus_show_pwm_enable(struct device *dev, >>>>> + struct device_attribute *da, char *buf) >>> +{ >>>>> + struct pmbus_fan_ctrl *fan = pwm_enable_to_pmbus_fan_ctrl(da); >>>>> + struct i2c_client *client = to_i2c_client(dev->parent); >>>>> + struct pmbus_data *data = i2c_get_clientdata(client); >>>>> + long mode; >>> + >>>>> + mutex_lock(&data->update_lock); >>> + >>> + >>>>> + if (data->info->get_pwm_mode) { >>>>> + u8 config = PB_FAN_CONFIG_PUT(fan->id, fan->config); >>> + >>>>> + mode = data->info->get_pwm_mode(fan->id, config, fan->command); >>>>> + } else { >>>>> + struct pmbus_sensor sensor = { >>>>> + .class = PSC_FAN, >>>>> + .data = fan->command, >>>>> + }; >>>>> + long command; >>> + >>>>> + command = pmbus_reg2data(data, &sensor); >>> + >>>>> + /* XXX: Need to do something sensible */ >>>>> + if (fan->config & PB_FAN_CONFIG_RPM) >>>>> + mode = 2; >>>>> + else >>>>> + mode = (command >= 0 && command < 100); >>>>> + } >>> + >>>>> + mutex_unlock(&data->update_lock); >>> + >>>>> + return snprintf(buf, PAGE_SIZE, "%ld\n", mode); >>> +} >>> + >>> +static ssize_t pmbus_set_pwm_enable(struct device *dev, >>>>> + struct device_attribute *da, >>>>> + const char *buf, size_t count) >>> +{ >>>>> + struct pmbus_fan_ctrl *fan = pwm_enable_to_pmbus_fan_ctrl(da); >>>>> + struct i2c_client *client = to_i2c_client(dev->parent); >>>>> + struct pmbus_data *data = i2c_get_clientdata(client); >>>>> + int config_addr, command_addr; >>>>> + struct pmbus_sensor sensor; >>>>> + ssize_t rv = count; >>>>> + long mode; >>> + >>>>> + if (kstrtol(buf, 10, &mode) < 0) >>>>> + return -EINVAL; >>> + >>>>> + mutex_lock(&data->update_lock); >>> + >>>>> + sensor.class = PSC_FAN; >>> + >>>>> + config_addr = (fan->id < 2) ? PMBUS_FAN_CONFIG_12 : PMBUS_FAN_CONFIG_34; >>>>> + command_addr = config_addr + 1 + (fan->id & 1); >>> + >>>>> + if (data->info->set_pwm_mode) { >>>>> + u8 config = PB_FAN_CONFIG_PUT(fan->id, fan->config); >>>>> + u16 command = fan->command; >>> + >>>>> + rv = data->info->set_pwm_mode(fan->id, mode, &config, &command); >>>>> + if (rv < 0) >>>>> + goto done; >>> + >>>>> + fan->config = PB_FAN_CONFIG_GET(fan->id, config); >>>>> + fan->command = command; >>>>> + } else { >>>>> + fan->config &= ~PB_FAN_CONFIG_RPM; >>>>> + switch (mode) { >>>>> + case 0: >>>>> + case 1: >>>>> + /* XXX: Safe at least? */ >>>>> + fan->command = pmbus_data2reg(data, &sensor, 100); >>>>> + break; >>>>> + case 2: >>>>> + default: >>>>> + /* XXX: Safe at least? */ >>>>> + fan->command = 0xffff; >>>>> + break; >>>>> + } >>>>> + } >>> + >>>>> + rv = pmbus_update_byte_data(client, fan->page, config_addr, >>>>> + PB_FAN_CONFIG_PUT(fan->id, fan->config), >>>>> + PB_FAN_CONFIG_MASK(fan->id)); >>>>> + if (rv < 0) >>>>> + goto done; >>> + >>>>> + rv = pmbus_write_word_data(client, fan->page, command_addr, >>>>> + fan->command); >>> + >>> +done: >>>>> + mutex_unlock(&data->update_lock); >>> + >>>>> + if (rv < 0) >>>>> + return rv; >>> + >>>>> + return count; >>> +} >>> + >>> static int pmbus_add_attribute(struct pmbus_data *data, struct attribute *attr) >>> { >>>>> if (data->num_attributes >= data->max_attributes - 1) { >>> @@ -1094,6 +1339,51 @@ static int pmbus_add_sensor_attrs(struct i2c_client *client, >>>>> return 0; >>> } >>> >>> +static int pmbus_add_fan_ctrl_attr(struct pmbus_data *data, >>>>> + struct pmbus_fan_ctrl_attr *fa, >>>>> + const char *name_fmt, >>>>> + ssize_t (*show)(struct device *dev, >>>>> + struct device_attribute *attr, >>>>> + char *buf), >>>>> + ssize_t (*store)(struct device *dev, >>>>> + struct device_attribute *attr, >>>>> + const char *buf, size_t count), >>>>> + int idx) >>> +{ >>>>> + struct device_attribute *da; >>> + >>>>> + da = &fa->attribute; >>> + >>>>> + snprintf(fa->name, sizeof(fa->name), name_fmt, idx); >>>>> + pmbus_dev_attr_init(da, fa->name, 0644, show, store); >>> + >>>>> + return pmbus_add_attribute(data, &da->attr); >>> +} >>> + >>> +static inline int pmbus_add_fan_target_attr(struct pmbus_data *data, >>>>> + struct pmbus_fan_ctrl *fan) >>> +{ >>>>> + return pmbus_add_fan_ctrl_attr(data, &fan->fan_target, "fan%d_target", >>>>> + pmbus_show_fan_target, >>>>> + pmbus_set_fan_target, fan->index); >>> +} >>> + >>> +static inline int pmbus_add_pwm_attr(struct pmbus_data *data, >>>>> + struct pmbus_fan_ctrl *fan) >>> +{ >>> + >>>>> + return pmbus_add_fan_ctrl_attr(data, &fan->pwm, "pwm%d", pmbus_show_pwm, >>>>> + pmbus_set_pwm, fan->index); >>> +} >>> + >>> +static inline int pmbus_add_pwm_enable_attr(struct pmbus_data *data, >>>>> + struct pmbus_fan_ctrl *fan) >>> +{ >>>>> + return pmbus_add_fan_ctrl_attr(data, &fan->pwm_enable, "pwm%d_enable", >>>>> + pmbus_show_pwm_enable, >>>>> + pmbus_set_pwm_enable, fan->index); >>> +} >>> + >>> static const struct pmbus_limit_attr vin_limit_attrs[] = { >>>>> { >>>>> .reg = PMBUS_VIN_UV_WARN_LIMIT, >>> @@ -1565,6 +1855,13 @@ static const int pmbus_fan_config_registers[] = { >>>>> PMBUS_FAN_CONFIG_34 >>> }; >>> >>> +static const int pmbus_fan_command_registers[] = { >>>>> + PMBUS_FAN_COMMAND_1, >>>>> + PMBUS_FAN_COMMAND_2, >>>>> + PMBUS_FAN_COMMAND_3, >>>>> + PMBUS_FAN_COMMAND_4, >>> +}; >>> + >>> static const int pmbus_fan_status_registers[] = { >>>>> PMBUS_STATUS_FAN_12, >>>>> PMBUS_STATUS_FAN_12, >>> @@ -1587,6 +1884,39 @@ static const u32 pmbus_fan_status_flags[] = { >>> }; >>> >>> /* Fans */ >>> +static int pmbus_add_fan_ctrl(struct i2c_client *client, >>>>> + struct pmbus_data *data, int index, int page, int id, >>>>> + u8 config) >>> +{ >>>>> + struct pmbus_fan_ctrl *fan; >>>>> + int rv; >>> + >>>>> + fan = devm_kzalloc(data->dev, sizeof(*fan), GFP_KERNEL); >>>>> + if (!fan) >>>>> + return -ENOMEM; >>> + >>>>> + fan->index = index; >>>>> + fan->page = page; >>>>> + fan->id = id; >>>>> + fan->config = config; >>> + >>>>> + rv = _pmbus_read_word_data(client, page, >>>>> + pmbus_fan_command_registers[id]); >>>>> + if (rv < 0) >>>>> + return rv; >>>>> + fan->command = rv; >>> + >>>>> + rv = pmbus_add_fan_target_attr(data, fan); >>>>> + if (rv < 0) >>>>> + return rv; >>> + >>>>> + rv = pmbus_add_pwm_attr(data, fan); >>>>> + if (rv < 0) >>>>> + return rv; >>> + >>>>> + return pmbus_add_pwm_enable_attr(data, fan); >>> +} >>> + >>> static int pmbus_add_fan_attributes(struct i2c_client *client, >>>>> struct pmbus_data *data) >>> { >>> @@ -1624,6 +1954,11 @@ static int pmbus_add_fan_attributes(struct i2c_client *client, >>>>> PSC_FAN, true, true) == NULL) >>>>> return -ENOMEM; >>> >>>>> + ret = pmbus_add_fan_ctrl(client, data, index, page, f, >>>>> + regval); >>>>> + if (ret < 0) >>>>> + return ret; >>> + >>>>> /* >>>>> * Each fan status register covers multiple fans, >>>>> * so we have to do some magic. >>> >>
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