The implementation makes use of the new fan control virtual registers exposed
by the pmbus core. It mixes use of the default implementations with some
overrides via the read/write handlers to handle FAN_COMMAND_1 on the MAX31785,
whose definition breaks the value range into various control bands dependent on
RPM or PWM mode.
Signed-off-by: Andrew Jeffery <andrew@xxxxxxxx>
---
Documentation/hwmon/max31785 | 7 ++-
drivers/hwmon/pmbus/max31785.c | 138 +++++++++++++++++++++++++++++++++-
2 files changed, 144 insertions(+), 1 deletion(-)
diff --git a/Documentation/hwmon/max31785 b/Documentation/hwmon/max31785
index 45fb6093dec2..7b0a0a8cdb6b 100644
--- a/Documentation/hwmon/max31785
+++ b/Documentation/hwmon/max31785
@@ -32,6 +32,7 @@ Sysfs attributes
fan[1-4]_alarm Fan alarm.
fan[1-4]_fault Fan fault.
fan[1-4]_input Fan RPM.
+fan[1-4]_target Fan input target
in[1-6]_crit Critical maximum output voltage
in[1-6]_crit_alarm Output voltage critical high alarm
@@ -44,6 +45,12 @@ in[1-6]_max_alarm Output voltage high alarm
in[1-6]_min Minimum output voltage
in[1-6]_min_alarm Output voltage low alarm
+pwm[1-4] Fan target duty cycle (0..255)
+pwm[1-4]_enable 0: Full-speed
+ 1: Manual PWM control
+ 2: Automatic PWM (tach-feedback RPM fan-control)
+ 3: Automatic closed-loop (temp-feedback fan-control)
+
temp[1-11]_crit Critical high temperature
temp[1-11]_crit_alarm Chip temperature critical high alarm
temp[1-11]_input Measured temperature
diff --git a/drivers/hwmon/pmbus/max31785.c b/drivers/hwmon/pmbus/max31785.c
index 9313849d5160..2699134dfbe7 100644
--- a/drivers/hwmon/pmbus/max31785.c
+++ b/drivers/hwmon/pmbus/max31785.c
@@ -20,8 +20,136 @@ enum max31785_regs {
#define MAX31785_NR_PAGES 23
+static int max31785_get_pwm(struct i2c_client *client, int page)
+{
+ int rv;
+
+ rv = pmbus_get_fan_rate_device(client, page, 0, percent);
+ if (rv < 0)
+ return rv;
+ else if (rv >= 0x8000)
+ return 0;
+ else if (rv >= 0x2711)
+ return 0x2710;
+
+ return rv;
+}
+
+static int max31785_get_pwm_mode(struct i2c_client *client, int page)
+{
+ int config;
+ int command;
+
+ config = pmbus_read_byte_data(client, page, PMBUS_FAN_CONFIG_12);
+ if (config < 0)
+ return config;
+
+ command = pmbus_read_word_data(client, page, PMBUS_FAN_COMMAND_1);
+ if (command < 0)
+ return command;
+
+ if (config & PB_FAN_1_RPM)
+ return (command >= 0x8000) ? 3 : 2;
+
+ if (command >= 0x8000)
+ return 3;
+ else if (command >= 0x2711)
+ return 0;
+
+ return 1;
+}
+
+static int max31785_read_word_data(struct i2c_client *client, int page,
+ int reg)
+{
+ int rv;
+
+ switch (reg) {
+ case PMBUS_VIRT_PWM_1:
+ rv = max31785_get_pwm(client, page);
+ break;
+ case PMBUS_VIRT_PWM_ENABLE_1:
+ rv = max31785_get_pwm_mode(client, page);
+ break;
+ default:
+ rv = -ENODATA;
+ break;
+ }
+
+ return rv;
+}
+
+static inline u32 max31785_scale_pwm(u32 sensor_val)
+{
+ /*
+ * The datasheet describes the accepted value range for manual PWM as
+ * [0, 0x2710], while the hwmon pwmX sysfs interface accepts values in
+ * [0, 255]. The MAX31785 uses DIRECT mode to scale the FAN_COMMAND
+ * registers and in PWM mode the coefficients are m=1, b=0, R=2. The
+ * important observation here is that 0x2710 == 10000 == 100 * 100.
+ *
+ * R=2 (== 10^2 == 100) accounts for scaling the value provided at the
+ * sysfs interface into the required hardware resolution, but it does
+ * not yet yield a value that we can write to the device (this initial
+ * scaling is handled by pmbus_data2reg()). Multiplying by 100 below
+ * translates the parameter value into the percentage units required by
+ * PMBus, and then we scale back by 255 as required by the hwmon pwmX
+ * interface to yield the percentage value at the appropriate
+ * resolution for hardware.
+ */
+ return (sensor_val * 100) / 255;
+}
+
+static int max31785_pwm_enable(struct i2c_client *client, int page,
+ u16 word)
+{
+ int config = 0;
+ int rate;
+
+ switch (word) {
+ case 0:
+ rate = 0x7fff;
+ break;
+ case 1:
+ rate = pmbus_get_fan_rate_cached(client, page, 0, percent);
+ rate = max31785_scale_pwm(rate);
+ if (rate < 0)
+ return rate;
+ break;
+ case 2:
+ config = PB_FAN_1_RPM;
+ rate = pmbus_get_fan_rate_cached(client, page, 0, rpm);
+ if (rate < 0)
+ return rate;
+ break;
+ case 3:
+ rate = 0xffff;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return pmbus_update_fan(client, page, 0, config, PB_FAN_1_RPM, rate);
+}
+
+static int max31785_write_word_data(struct i2c_client *client, int page,
+ int reg, u16 word)
+{
+ switch (reg) {
+ case PMBUS_VIRT_PWM_1:
+ return pmbus_update_fan(client, page, 0, 0, PB_FAN_1_RPM,
+ max31785_scale_pwm(word));
+ case PMBUS_VIRT_PWM_ENABLE_1:
+ return max31785_pwm_enable(client, page, word);
+ default:
+ break;
+ }
+
+ return -ENODATA;
+}
+
#define MAX31785_FAN_FUNCS \
- (PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12)
+ (PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12 | PMBUS_HAVE_PWM12)
#define MAX31785_TEMP_FUNCS \
(PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP)
@@ -32,11 +160,19 @@ enum max31785_regs {
static const struct pmbus_driver_info max31785_info = {
.pages = MAX31785_NR_PAGES,
+ .write_word_data = max31785_write_word_data,
+ .read_word_data = max31785_read_word_data,
+
/* RPM */
.format[PSC_FAN] = direct,
.m[PSC_FAN] = 1,
.b[PSC_FAN] = 0,
.R[PSC_FAN] = 0,
+ /* PWM */
+ .format[PSC_PWM] = direct,
+ .m[PSC_PWM] = 1,
+ .b[PSC_PWM] = 0,
+ .R[PSC_PWM] = 2,
.func[0] = MAX31785_FAN_FUNCS,
.func[1] = MAX31785_FAN_FUNCS,
.func[2] = MAX31785_FAN_FUNCS,
--
git-series 0.9.1
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