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| Started by | Andrew Jeffery <andrew@aj.id.au> |
|---|---|
| First post | 2017-08-02 09:20 +0200 |
| Last post | 2017-08-10 18:20 +0200 |
| Articles | 4 — 2 participants |
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[PATCH v2 0/4] pmbus: Expand fan support and add MAX31785 driver Andrew Jeffery <andrew@aj.id.au> - 2017-08-02 09:20 +0200
[PATCH v2 2/4] hwmon: pmbus: Add fan control support Andrew Jeffery <andrew@aj.id.au> - 2017-08-02 09:20 +0200
[PATCH v2 1/4] dt-bindings: hwmon: pmbus: Add Maxim MAX31785 documentation Andrew Jeffery <andrew@aj.id.au> - 2017-08-02 09:20 +0200
Re: [PATCH v2 1/4] dt-bindings: hwmon: pmbus: Add Maxim MAX31785 documentation Rob Herring <robh@kernel.org> - 2017-08-10 18:20 +0200
| From | Andrew Jeffery <andrew@aj.id.au> |
|---|---|
| Date | 2017-08-02 09:20 +0200 |
| Subject | [PATCH v2 0/4] pmbus: Expand fan support and add MAX31785 driver |
| Message-ID | <u9W6J-6Ni-9@gated-at.bofh.it> |
Hello, v1[1] spent some time in the OpenBMC kernel tree and it shook out a few issues: 1. The machines I was testing against had pre-prammed the installed-bit in FAN_CONFIG_1_2 2. There appears to be a hardware issue with some back-to-back writes to the MAX31785 Point 1. is a policy issue so we should have the ability to specify behaviour in the devicetree. As such the bindings documentation has been updated to suit. Point 2, well, it's a little ugly. We're in contact with Maxim to better understand the nature of the issue. Patch 4 introduces a work-around. I've kept this separate from the introduction of the driver so it's implementation and the demonstration of new pmbus core features isn't obscured. The work-around has proved reliable so-far, across a number of machines. [1] https://lkml.org/lkml/2017/7/27/116 Changes from v1 to v2: * Add the use-stored-presence devicetree property describing the hardware as canonical in terms of fan presence. * Small optimsation in pmbus_update_fans(): Don't write FAN_CONFIG_x_y unless the new value is different to the current value * Update the MAX31785 driver to consume use-stored-presence from the devicetree * Add the back-to-back write work-around Changes between RFC v2 to (non-RFC) v1 * Clean up issues identified in comments on the pmbus core changes * Define and implement bindings for the MAX31785 * Clean up issues identified in comments on the max31785 driver Andrew Jeffery (4): dt-bindings: hwmon: pmbus: Add Maxim MAX31785 documentation hwmon: pmbus: Add fan control support pmbus: Add driver for Maxim MAX31785 Intelligent Fan Controller pmbus: max31785: Work around back-to-back writes with FAN_CONFIG_1_2 .../devicetree/bindings/hwmon/pmbus/max31785.txt | 126 ++++ drivers/hwmon/pmbus/Kconfig | 10 + drivers/hwmon/pmbus/Makefile | 1 + drivers/hwmon/pmbus/max31785.c | 762 +++++++++++++++++++++ drivers/hwmon/pmbus/pmbus.h | 29 + drivers/hwmon/pmbus/pmbus_core.c | 224 +++++- 6 files changed, 1137 insertions(+), 15 deletions(-) create mode 100644 Documentation/devicetree/bindings/hwmon/pmbus/max31785.txt create mode 100644 drivers/hwmon/pmbus/max31785.c -- 2.11.0
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| From | Andrew Jeffery <andrew@aj.id.au> |
|---|---|
| Date | 2017-08-02 09:20 +0200 |
| Subject | [PATCH v2 2/4] hwmon: pmbus: Add fan control support |
| Message-ID | <u9W6J-6Ni-17@gated-at.bofh.it> |
| In reply to | #1701781 |
Expose fanX_target, pwmX and pwmX_enable hwmon sysfs attributes.
Fans in a PMBus device are driven by the configuration of two registers:
FAN_CONFIG_x_y and FAN_COMMAND_x: FAN_CONFIG_x_y dictates how the fan
and the tacho operate (if installed), while FAN_COMMAND_x sets the
desired fan rate. The unit of FAN_COMMAND_x is dependent on the
operational fan mode, RPM or PWM percent duty, as determined by the
corresponding FAN_CONFIG_x_y.
The mapping of fanX_target, pwmX and pwmX_enable onto FAN_CONFIG_x_y and
FAN_COMMAND_x is implemented with the addition of virtual registers and
generic implementations in the core:
1. PMBUS_VIRT_FAN_TARGET_x
2. PMBUS_VIRT_PWM_x
3. PMBUS_VIRT_PWM_ENABLE_x
The virtual registers facilitate the necessary side-effects of each
access. Examples of the read case, assuming m = 1, b = 0, R = 0:
Read | With || Gives
-------------------------------------------------------
Attribute | FAN_CONFIG_x_y | FAN_COMMAND_y || Value
----------------------------------------------++-------
fanX_target | ~PB_FAN_z_RPM | 0x0001 || 1
pwm1 | ~PB_FAN_z_RPM | 0x0064 || 255
pwmX_enable | ~PB_FAN_z_RPM | 0x0001 || 1
fanX_target | PB_FAN_z_RPM | 0x0001 || 1
pwm1 | PB_FAN_z_RPM | 0x0064 || 0
pwmX_enable | PB_FAN_z_RPM | 0x0001 || 1
And the write case:
Write | With || Sets
-------------+-------++----------------+---------------
Attribute | Value || FAN_CONFIG_x_y | FAN_COMMAND_x
-------------+-------++----------------+---------------
fanX_target | 1 || PB_FAN_z_RPM | 0x0001
pwmX | 255 || ~PB_FAN_z_RPM | 0x0064
pwmX_enable | 1 || ~PB_FAN_z_RPM | 0x0064
Also, the DIRECT mode scaling of some controllers is different between
RPM and PWM percent duty control modes, so PSC_PWM is introduced to
capture the necessary coefficients.
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
---
drivers/hwmon/pmbus/pmbus.h | 29 +++++
drivers/hwmon/pmbus/pmbus_core.c | 224 ++++++++++++++++++++++++++++++++++++---
2 files changed, 238 insertions(+), 15 deletions(-)
diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
index bfcb13bae34b..a863b8fed16f 100644
--- a/drivers/hwmon/pmbus/pmbus.h
+++ b/drivers/hwmon/pmbus/pmbus.h
@@ -190,6 +190,28 @@ enum pmbus_regs {
PMBUS_VIRT_VMON_UV_FAULT_LIMIT,
PMBUS_VIRT_VMON_OV_FAULT_LIMIT,
PMBUS_VIRT_STATUS_VMON,
+
+ /*
+ * RPM and PWM Fan control
+ *
+ * Drivers wanting to expose PWM control must define the behaviour of
+ * PMBUS_VIRT_PWM_ENABLE_[1-4] in the {read,write}_word_data callback.
+ *
+ * pmbus core provides default implementations for
+ * PMBUS_VIRT_FAN_TARGET_[1-4] and PMBUS_VIRT_PWM_[1-4].
+ */
+ PMBUS_VIRT_FAN_TARGET_1,
+ PMBUS_VIRT_FAN_TARGET_2,
+ PMBUS_VIRT_FAN_TARGET_3,
+ PMBUS_VIRT_FAN_TARGET_4,
+ PMBUS_VIRT_PWM_1,
+ PMBUS_VIRT_PWM_2,
+ PMBUS_VIRT_PWM_3,
+ PMBUS_VIRT_PWM_4,
+ PMBUS_VIRT_PWM_ENABLE_1,
+ PMBUS_VIRT_PWM_ENABLE_2,
+ PMBUS_VIRT_PWM_ENABLE_3,
+ PMBUS_VIRT_PWM_ENABLE_4,
};
/*
@@ -223,6 +245,8 @@ 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)
*/
@@ -313,6 +337,7 @@ enum pmbus_sensor_classes {
PSC_POWER,
PSC_TEMPERATURE,
PSC_FAN,
+ PSC_PWM,
PSC_NUM_CLASSES /* Number of power sensor classes */
};
@@ -339,6 +364,8 @@ enum pmbus_sensor_classes {
#define PMBUS_HAVE_STATUS_FAN34 BIT(17)
#define PMBUS_HAVE_VMON BIT(18)
#define PMBUS_HAVE_STATUS_VMON BIT(19)
+#define PMBUS_HAVE_PWM12 BIT(20)
+#define PMBUS_HAVE_PWM34 BIT(21)
enum pmbus_data_format { linear = 0, direct, vid };
enum vrm_version { vr11 = 0, vr12 };
@@ -413,6 +440,8 @@ int pmbus_write_byte_data(struct i2c_client *client, int page, u8 reg,
u8 value);
int pmbus_update_byte_data(struct i2c_client *client, int page, u8 reg,
u8 mask, u8 value);
+int pmbus_update_fan(struct i2c_client *client, int page, int id,
+ u8 config, u8 mask, u16 command);
void pmbus_clear_faults(struct i2c_client *client);
bool pmbus_check_byte_register(struct i2c_client *client, int page, int reg);
bool pmbus_check_word_register(struct i2c_client *client, int page, int reg);
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index ba59eaef2e07..93fb58787b99 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -63,6 +63,7 @@ struct pmbus_sensor {
u16 reg; /* register */
enum pmbus_sensor_classes class; /* sensor class */
bool update; /* runtime sensor update needed */
+ bool convert; /* Whether or not to apply linear/vid/direct */
int data; /* Sensor data.
Negative if there was a read error */
};
@@ -118,6 +119,27 @@ struct pmbus_data {
u8 currpage;
};
+static const int pmbus_fan_rpm_mask[] = {
+ PB_FAN_1_RPM,
+ PB_FAN_2_RPM,
+ PB_FAN_1_RPM,
+ PB_FAN_2_RPM,
+};
+
+static const int pmbus_fan_config_registers[] = {
+ PMBUS_FAN_CONFIG_12,
+ PMBUS_FAN_CONFIG_12,
+ PMBUS_FAN_CONFIG_34,
+ 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,
+};
+
void pmbus_clear_cache(struct i2c_client *client)
{
struct pmbus_data *data = i2c_get_clientdata(client);
@@ -188,6 +210,31 @@ int pmbus_write_word_data(struct i2c_client *client, u8 page, u8 reg, u16 word)
}
EXPORT_SYMBOL_GPL(pmbus_write_word_data);
+int pmbus_update_fan(struct i2c_client *client, int page, int id,
+ u8 config, u8 mask, u16 command)
+{
+ int from, rv;
+ u8 to;
+
+ from = pmbus_read_byte_data(client, page,
+ pmbus_fan_config_registers[id]);
+ if (from < 0)
+ return from;
+
+ to = (from & ~mask) | (config & mask);
+
+ if (to != from) {
+ rv = pmbus_write_byte_data(client, page,
+ pmbus_fan_config_registers[id], to);
+ if (rv < 0)
+ return rv;
+ }
+
+ return pmbus_write_word_data(client, page,
+ pmbus_fan_command_registers[id], command);
+}
+EXPORT_SYMBOL_GPL(pmbus_update_fan);
+
/*
* _pmbus_write_word_data() is similar to pmbus_write_word_data(), but checks if
* a device specific mapping function exists and calls it if necessary.
@@ -204,8 +251,40 @@ static int _pmbus_write_word_data(struct i2c_client *client, int page, int reg,
if (status != -ENODATA)
return status;
}
- if (reg >= PMBUS_VIRT_BASE)
- return -ENXIO;
+ if (reg >= PMBUS_VIRT_BASE) {
+ int id, bit;
+
+ switch (reg) {
+ case PMBUS_VIRT_FAN_TARGET_1:
+ case PMBUS_VIRT_FAN_TARGET_2:
+ case PMBUS_VIRT_FAN_TARGET_3:
+ case PMBUS_VIRT_FAN_TARGET_4:
+ id = reg - PMBUS_VIRT_FAN_TARGET_1;
+ bit = pmbus_fan_rpm_mask[id];
+ status = pmbus_update_fan(client, page, id, bit, bit,
+ word);
+ break;
+ case PMBUS_VIRT_PWM_1:
+ case PMBUS_VIRT_PWM_2:
+ case PMBUS_VIRT_PWM_3:
+ case PMBUS_VIRT_PWM_4:
+ {
+ u32 command = word;
+
+ id = reg - PMBUS_VIRT_PWM_1;
+ bit = pmbus_fan_rpm_mask[id];
+ command *= 100;
+ command /= 255;
+ status = pmbus_update_fan(client, page, id, 0, bit,
+ command);
+ break;
+ }
+ default:
+ status = -ENXIO;
+ break;
+ }
+ return status;
+ }
return pmbus_write_word_data(client, page, reg, word);
}
@@ -221,6 +300,9 @@ int pmbus_read_word_data(struct i2c_client *client, u8 page, u8 reg)
}
EXPORT_SYMBOL_GPL(pmbus_read_word_data);
+static int pmbus_get_fan_command(struct i2c_client *client, int page, int id,
+ enum pmbus_fan_mode mode);
+
/*
* _pmbus_read_word_data() is similar to pmbus_read_word_data(), but checks if
* a device specific mapping function exists and calls it if necessary.
@@ -236,8 +318,42 @@ static int _pmbus_read_word_data(struct i2c_client *client, int page, int reg)
if (status != -ENODATA)
return status;
}
- if (reg >= PMBUS_VIRT_BASE)
- return -ENXIO;
+ if (reg >= PMBUS_VIRT_BASE) {
+ int id;
+
+ switch (reg) {
+ case PMBUS_VIRT_FAN_TARGET_1:
+ case PMBUS_VIRT_FAN_TARGET_2:
+ case PMBUS_VIRT_FAN_TARGET_3:
+ case PMBUS_VIRT_FAN_TARGET_4:
+ id = reg - PMBUS_VIRT_FAN_TARGET_1;
+ status = pmbus_get_fan_command(client, page, id, rpm);
+ break;
+ case PMBUS_VIRT_PWM_1:
+ case PMBUS_VIRT_PWM_2:
+ case PMBUS_VIRT_PWM_3:
+ case PMBUS_VIRT_PWM_4:
+ {
+ int rv;
+
+ id = reg - PMBUS_VIRT_PWM_1;
+ rv = pmbus_get_fan_command(client, page, id, percent);
+ if (rv < 0)
+ return rv;
+
+ rv *= 255;
+ rv /= 100;
+
+ status = rv;
+ break;
+ }
+ default:
+ status = -ENXIO;
+ break;
+ }
+
+ return status;
+ }
return pmbus_read_word_data(client, page, reg);
}
@@ -304,6 +420,28 @@ static int _pmbus_read_byte_data(struct i2c_client *client, int page, int reg)
return pmbus_read_byte_data(client, page, reg);
}
+static int pmbus_get_fan_command(struct i2c_client *client, int page, int id,
+ enum pmbus_fan_mode mode)
+{
+ int config;
+
+ config = _pmbus_read_byte_data(client, page,
+ pmbus_fan_config_registers[id]);
+ if (config < 0)
+ return config;
+
+ /*
+ * We can't meaningfully translate between PWM and RPM, so if the
+ * attribute mode (fan[1-*]_target is RPM, pwm[1-*] and pwm[1-*]_enable
+ * are PWM) doesn't match the hardware mode, then report 0 instead.
+ */
+ if ((mode == rpm) != (!!(config & pmbus_fan_rpm_mask[id])))
+ return 0;
+
+ return _pmbus_read_word_data(client, page,
+ pmbus_fan_command_registers[id]);
+}
+
static void pmbus_clear_fault_page(struct i2c_client *client, int page)
{
_pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS);
@@ -489,7 +627,7 @@ static long pmbus_reg2data_direct(struct pmbus_data *data,
/* X = 1/m * (Y * 10^-R - b) */
R = -R;
/* scale result to milli-units for everything but fans */
- if (sensor->class != PSC_FAN) {
+ if (!(sensor->class == PSC_FAN || sensor->class == PSC_PWM)) {
R += 3;
b *= 1000;
}
@@ -539,6 +677,9 @@ static long pmbus_reg2data(struct pmbus_data *data, struct pmbus_sensor *sensor)
{
long val;
+ if (!sensor->convert)
+ return sensor->data;
+
switch (data->info->format[sensor->class]) {
case direct:
val = pmbus_reg2data_direct(data, sensor);
@@ -642,7 +783,7 @@ static u16 pmbus_data2reg_direct(struct pmbus_data *data,
}
/* Calculate Y = (m * X + b) * 10^R */
- if (sensor->class != PSC_FAN) {
+ if (!(sensor->class == PSC_FAN || sensor->class == PSC_PWM)) {
R -= 3; /* Adjust R and b for data in milli-units */
b *= 1000;
}
@@ -673,6 +814,9 @@ static u16 pmbus_data2reg(struct pmbus_data *data,
{
u16 regval;
+ if (!sensor->convert)
+ return val;
+
switch (data->info->format[sensor->class]) {
case direct:
regval = pmbus_data2reg_direct(data, sensor, val);
@@ -895,12 +1039,18 @@ static struct pmbus_sensor *pmbus_add_sensor(struct pmbus_data *data,
return NULL;
a = &sensor->attribute;
- snprintf(sensor->name, sizeof(sensor->name), "%s%d_%s",
- name, seq, type);
+ if (type)
+ snprintf(sensor->name, sizeof(sensor->name), "%s%d_%s",
+ name, seq, type);
+ else
+ snprintf(sensor->name, sizeof(sensor->name), "%s%d",
+ name, seq);
+
sensor->page = page;
sensor->reg = reg;
sensor->class = class;
sensor->update = update;
+ sensor->convert = true;
pmbus_dev_attr_init(a, sensor->name,
readonly ? S_IRUGO : S_IRUGO | S_IWUSR,
pmbus_show_sensor, pmbus_set_sensor);
@@ -1558,13 +1708,6 @@ static const int pmbus_fan_registers[] = {
PMBUS_READ_FAN_SPEED_4
};
-static const int pmbus_fan_config_registers[] = {
- PMBUS_FAN_CONFIG_12,
- PMBUS_FAN_CONFIG_12,
- PMBUS_FAN_CONFIG_34,
- PMBUS_FAN_CONFIG_34
-};
-
static const int pmbus_fan_status_registers[] = {
PMBUS_STATUS_FAN_12,
PMBUS_STATUS_FAN_12,
@@ -1587,6 +1730,48 @@ 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_sensor *sensor;
+ int rv;
+
+ rv = _pmbus_read_word_data(client, page,
+ pmbus_fan_command_registers[id]);
+ if (rv < 0)
+ return rv;
+
+ sensor = pmbus_add_sensor(data, "fan", "target", index, page,
+ PMBUS_VIRT_FAN_TARGET_1 + id, PSC_FAN,
+ true, false);
+
+ if (!sensor)
+ return -ENOMEM;
+
+ if (!((data->info->func[page] & PMBUS_HAVE_PWM12) ||
+ (data->info->func[page] & PMBUS_HAVE_PWM34)))
+ return 0;
+
+ sensor = pmbus_add_sensor(data, "pwm", NULL, index, page,
+ PMBUS_VIRT_PWM_1 + id, PSC_PWM,
+ true, false);
+
+ if (!sensor)
+ return -ENOMEM;
+
+ sensor = pmbus_add_sensor(data, "pwm", "enable", index, page,
+ PMBUS_VIRT_PWM_ENABLE_1 + id, PSC_PWM,
+ true, false);
+
+ if (!sensor)
+ return -ENOMEM;
+
+ sensor->convert = false;
+
+ return 0;
+}
+
static int pmbus_add_fan_attributes(struct i2c_client *client,
struct pmbus_data *data)
{
@@ -1624,6 +1809,15 @@ static int pmbus_add_fan_attributes(struct i2c_client *client,
PSC_FAN, true, true) == NULL)
return -ENOMEM;
+ /* Fan control */
+ if (pmbus_check_word_register(client, page,
+ pmbus_fan_command_registers[f])) {
+ 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.
--
2.11.0
[toc] | [prev] | [next] | [standalone]
| From | Andrew Jeffery <andrew@aj.id.au> |
|---|---|
| Date | 2017-08-02 09:20 +0200 |
| Subject | [PATCH v2 1/4] dt-bindings: hwmon: pmbus: Add Maxim MAX31785 documentation |
| Message-ID | <u9W6J-6Ni-21@gated-at.bofh.it> |
| In reply to | #1701781 |
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
---
.../devicetree/bindings/hwmon/pmbus/max31785.txt | 126 +++++++++++++++++++++
1 file changed, 126 insertions(+)
create mode 100644 Documentation/devicetree/bindings/hwmon/pmbus/max31785.txt
diff --git a/Documentation/devicetree/bindings/hwmon/pmbus/max31785.txt b/Documentation/devicetree/bindings/hwmon/pmbus/max31785.txt
new file mode 100644
index 000000000000..8ddc4ea1958d
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/pmbus/max31785.txt
@@ -0,0 +1,126 @@
+Bindings for the Maxim MAX31785 Intelligent Fan Controller
+==========================================================
+
+Reference:
+[1] https://datasheets.maximintegrated.com/en/ds/MAX31785.pdf
+
+Required properties:
+- compatible : One of "maxim,max31785" or "maxim,max31785a"
+- reg : I2C address, one of 0x52, 0x53, 0x54, 0x55.
+- #address-cells : Must be 1
+- #size-cells : Must be 0
+
+Optional properties:
+- use-stored-presence : Do not treat the devicetree description as canon for
+ fan presence (the 'installed' bit of FAN_CONFIG_*).
+ Instead, rely on the on the default value store of
+ the device to populate it.
+
+Capabilities are configured through subnodes of the controller's node.
+
+Fans
+----
+
+Only fans with subnodes present will be considered as installed. If
+use-stored-presence is present in the parent node, then only fans that are both
+defined in the devicetree and have their installed bit set are considered
+installed.
+
+Required subnode properties:
+- compatible : Must be "pmbus-fan"
+- reg : The PMBus page the properties apply to.
+- maxim,fan-rotor-input : The type of rotor measurement provided to the
+ controller. Must be either "tach" for tachometer
+ pulses or "lock" for a locked-rotor signal.
+- maxim,fan-lock-polarity: Required iff maxim,fan-rotor-input is "lock". Valid
+ values are "low" for active low, "high" for active
+ high.
+
+Optional subnode properties:
+- fan-mode : "rpm" or "pwm". Default value is "pwm".
+- tach-pulses : Tachometer pulses per revolution. Valid values are
+ 1, 2, 3 or 4. The default is 1.
+- maxim,fan-no-fault-ramp: Do not ramp the fan to 100% PWM duty on detecting a
+ fan fault
+- maxim,fan-startup : The number of rotations required before taking
+ emergency action for an unresponsive fan and driving
+ it with 100% or 0% PWM duty, depending on the state
+ of maxim,fan-no-fault-ramp. Valid values are 0
+ (automatic spin-up disabled), 2, 4, or 8. Default
+ value is 0.
+- maxim,fan-health : Enable automated fan health check
+- maxim,fan-ramp : Configures how fast the device ramps the PWM duty
+ cycle from one value to another. Valid values are 0
+ to 7 inclusive, with values 0 - 2 configuring a
+ 1000ms update rate and 1 - 3% duty respective duty
+ increase, and 3 - 7 a 200ms update rate with a 1 -
+ 5% respective duty increase. Default value is 0.
+- maxim,fan-no-watchdog : Do not ramp fan to 100% PWM duty on failure to
+ update desired fan rate inside 10s. This implies
+ maxim,tmp-no-fault-ramp
+- maxim,tmp-no-fault-ramp: Do not ramp fan to 100% PWM duty on temperature
+ sensor fault detection. This implies
+ maxim,fan-no-watchdog
+- maxim,tmp-hysteresis : The temperature hysteresis used to determine
+ transitions to lower fan speed bands in the
+ temperature/fan rate lookup table. Valid values are
+ 2, 4, 6 or 8 (degrees celcius). Default value is 2.
+- maxim,fan-dual-tach : Enable dual tachometer functionality
+- maxim,fan-pwm-freq : The PWM frequency. Valid values are 30, 50, 100, 150
+ and 25000 (Hz). Default value is 30Hz.
+- maxim,fan-lookup-table : A 16-element cell array of alternating temperature
+ and rate values representing the look up table. The
+ rate units are set through the fan-mode property.
+- maxim,fan-fault-pin-mon: Ramp fans to 100% PWM duty when the FAULT pin is
+ asserted
+
+Temperature
+-----------
+
+Required subnode properties:
+- compatible : Must be "pmbus-temperature"
+- reg : The PMBus page the properties apply to.
+
+Optional subnode properties:
+- maxim,tmp-offset : Valid values are 0 - 30 (degrees celcius) inclusive.
+ Default value is 0.
+- maxim,tmp-fans : An array of fan indexes whose fans are controlled by
+ the current temperature sensor. Fans are indexed from
+ zero. The valid values are 0 - 5 inclusive.
+
+Example:
+ fan-max31785: max31785@52 {
+ reg = <0x52>;
+ compatible = "maxim,max31785";
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ fan@0 {
+ compatible = "pmbus-fan";
+ reg = <0>;
+ mode = "rpm";
+ tach-pulses = <1>;
+ maxim,fan-rotor-input = "tach";
+ maxim,fan-dual-tach;
+ };
+
+ fan@1 {
+ compatible = "pmbus-fan";
+ reg = <1>;
+ mode = "rpm";
+ tach-pulses = <1>;
+ maxim,fan-rotor-input = "tach";
+ maxim,tmp-hysteresis = <2>;
+ maxim,fan-lookup-table = <
+ /* Temperature RPM */
+ 0 1000
+ 10 2000
+ 20 3000
+ 30 4000
+ 40 5000
+ 50 6000
+ 60 7000
+ 70 8000
+ >;
+ };
+ };
--
2.11.0
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| From | Rob Herring <robh@kernel.org> |
|---|---|
| Date | 2017-08-10 18:20 +0200 |
| Subject | Re: [PATCH v2 1/4] dt-bindings: hwmon: pmbus: Add Maxim MAX31785 documentation |
| Message-ID | <ucYlI-806-31@gated-at.bofh.it> |
| In reply to | #1701784 |
On Wed, Aug 02, 2017 at 04:45:38PM +0930, Andrew Jeffery wrote:
> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> ---
> .../devicetree/bindings/hwmon/pmbus/max31785.txt | 126 +++++++++++++++++++++
> 1 file changed, 126 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/hwmon/pmbus/max31785.txt
>
> diff --git a/Documentation/devicetree/bindings/hwmon/pmbus/max31785.txt b/Documentation/devicetree/bindings/hwmon/pmbus/max31785.txt
> new file mode 100644
> index 000000000000..8ddc4ea1958d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/pmbus/max31785.txt
> @@ -0,0 +1,126 @@
> +Bindings for the Maxim MAX31785 Intelligent Fan Controller
> +==========================================================
This is the second fan controller binding I've seen recently. The other
being hwmon/aspeed-pwm-tacho.txt. I think some of this needs to be
common. There's only so many types of fans, right?
And we have the thermal binding which you don't appear to tie into.
> +
> +Reference:
> +[1] https://datasheets.maximintegrated.com/en/ds/MAX31785.pdf
> +
> +Required properties:
> +- compatible : One of "maxim,max31785" or "maxim,max31785a"
> +- reg : I2C address, one of 0x52, 0x53, 0x54, 0x55.
> +- #address-cells : Must be 1
> +- #size-cells : Must be 0
> +
> +Optional properties:
> +- use-stored-presence : Do not treat the devicetree description as canon for
Is this maxim specific? If so, needs a vendor prefix.
> + fan presence (the 'installed' bit of FAN_CONFIG_*).
> + Instead, rely on the on the default value store of
> + the device to populate it.
> +
> +Capabilities are configured through subnodes of the controller's node.
> +
> +Fans
> +----
> +
> +Only fans with subnodes present will be considered as installed. If
> +use-stored-presence is present in the parent node, then only fans that are both
> +defined in the devicetree and have their installed bit set are considered
> +installed.
> +
> +Required subnode properties:
> +- compatible : Must be "pmbus-fan"
What defines a pmbus-fan? Sounds generic, but then you have all these
maxim specific properties.
> +- reg : The PMBus page the properties apply to.
> +- maxim,fan-rotor-input : The type of rotor measurement provided to the
> + controller. Must be either "tach" for tachometer
> + pulses or "lock" for a locked-rotor signal.
> +- maxim,fan-lock-polarity: Required iff maxim,fan-rotor-input is "lock". Valid
> + values are "low" for active low, "high" for active
> + high.
> +
> +Optional subnode properties:
> +- fan-mode : "rpm" or "pwm". Default value is "pwm".
> +- tach-pulses : Tachometer pulses per revolution. Valid values are
> + 1, 2, 3 or 4. The default is 1.
> +- maxim,fan-no-fault-ramp: Do not ramp the fan to 100% PWM duty on detecting a
> + fan fault
> +- maxim,fan-startup : The number of rotations required before taking
> + emergency action for an unresponsive fan and driving
> + it with 100% or 0% PWM duty, depending on the state
> + of maxim,fan-no-fault-ramp. Valid values are 0
> + (automatic spin-up disabled), 2, 4, or 8. Default
> + value is 0.
> +- maxim,fan-health : Enable automated fan health check
> +- maxim,fan-ramp : Configures how fast the device ramps the PWM duty
> + cycle from one value to another. Valid values are 0
> + to 7 inclusive, with values 0 - 2 configuring a
> + 1000ms update rate and 1 - 3% duty respective duty
> + increase, and 3 - 7 a 200ms update rate with a 1 -
> + 5% respective duty increase. Default value is 0.
> +- maxim,fan-no-watchdog : Do not ramp fan to 100% PWM duty on failure to
> + update desired fan rate inside 10s. This implies
> + maxim,tmp-no-fault-ramp
> +- maxim,tmp-no-fault-ramp: Do not ramp fan to 100% PWM duty on temperature
> + sensor fault detection. This implies
> + maxim,fan-no-watchdog
> +- maxim,tmp-hysteresis : The temperature hysteresis used to determine
> + transitions to lower fan speed bands in the
> + temperature/fan rate lookup table. Valid values are
> + 2, 4, 6 or 8 (degrees celcius). Default value is 2.
> +- maxim,fan-dual-tach : Enable dual tachometer functionality
> +- maxim,fan-pwm-freq : The PWM frequency. Valid values are 30, 50, 100, 150
> + and 25000 (Hz). Default value is 30Hz.
> +- maxim,fan-lookup-table : A 16-element cell array of alternating temperature
> + and rate values representing the look up table. The
> + rate units are set through the fan-mode property.
> +- maxim,fan-fault-pin-mon: Ramp fans to 100% PWM duty when the FAULT pin is
> + asserted
> +
> +Temperature
> +-----------
> +
> +Required subnode properties:
> +- compatible : Must be "pmbus-temperature"
> +- reg : The PMBus page the properties apply to.
> +
> +Optional subnode properties:
> +- maxim,tmp-offset : Valid values are 0 - 30 (degrees celcius) inclusive.
> + Default value is 0.
> +- maxim,tmp-fans : An array of fan indexes whose fans are controlled by
> + the current temperature sensor. Fans are indexed from
> + zero. The valid values are 0 - 5 inclusive.
Why not use a phandle here.
> +
> +Example:
> + fan-max31785: max31785@52 {
> + reg = <0x52>;
> + compatible = "maxim,max31785";
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + fan@0 {
> + compatible = "pmbus-fan";
> + reg = <0>;
> + mode = "rpm";
> + tach-pulses = <1>;
> + maxim,fan-rotor-input = "tach";
> + maxim,fan-dual-tach;
> + };
> +
> + fan@1 {
> + compatible = "pmbus-fan";
> + reg = <1>;
> + mode = "rpm";
> + tach-pulses = <1>;
> + maxim,fan-rotor-input = "tach";
> + maxim,tmp-hysteresis = <2>;
> + maxim,fan-lookup-table = <
> + /* Temperature RPM */
> + 0 1000
> + 10 2000
> + 20 3000
> + 30 4000
> + 40 5000
> + 50 6000
> + 60 7000
> + 70 8000
> + >;
> + };
> + };
> --
> 2.11.0
>
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