On some boards, such as the LaCie 2Big Network v2 or 2Big NAS (based on
Marvell Kirkwood SoCs), an I2C fan controller is used but the alarm
signal is wired to a separate GPIO. Unfortunately, the gpio-fan driver
can't be used to handle GPIO alarm alone from DT: an error is returned
if the "gpios" DT property is missing.
This patch allows to use the gpio-fan driver even if the "alarm-gpios"
DT property is defined alone.
Signed-off-by: Simon Guinot <simon.guinot@xxxxxxxxxxxx>
---
.../devicetree/bindings/gpio/gpio-fan.txt | 6 ++-
drivers/hwmon/gpio-fan.c | 44 +++++++++++-----------
2 files changed, 27 insertions(+), 23 deletions(-)
v2 change:
- Fix sentence in binding document about having at least one of the
"gpios" or "alarm-gpios" properties set.
diff --git a/Documentation/devicetree/bindings/gpio/gpio-fan.txt b/Documentation/devicetree/bindings/gpio/gpio-fan.txt
index 2dd457a3469a..f996d428f132 100644
--- a/Documentation/devicetree/bindings/gpio/gpio-fan.txt
+++ b/Documentation/devicetree/bindings/gpio/gpio-fan.txt
@@ -2,16 +2,18 @@ Bindings for fan connected to GPIO lines
Required properties:
- compatible : "gpio-fan"
+
+Optional properties:
- gpios: Specifies the pins that map to bits in the control value,
ordered MSB-->LSB.
- gpio-fan,speed-map: A mapping of possible fan RPM speeds and the
control value that should be set to achieve them. This array
must have the RPM values in ascending order.
-
-Optional properties:
- alarm-gpios: This pin going active indicates something is wrong with
the fan, and a udev event will be fired.
+Note: At least one the "gpios" or "alarm-gpios" properties must be set.
+
Examples:
gpio_fan {
diff --git a/drivers/hwmon/gpio-fan.c b/drivers/hwmon/gpio-fan.c
index 36abf814b8c7..c241f5b0b7cf 100644
--- a/drivers/hwmon/gpio-fan.c
+++ b/drivers/hwmon/gpio-fan.c
@@ -404,10 +404,32 @@ static int gpio_fan_get_of_pdata(struct device *dev,
node = dev->of_node;
+ /* Alarm GPIO if one exists */
+ if (of_gpio_named_count(node, "alarm-gpios") > 0) {
+ struct gpio_fan_alarm *alarm;
+ int val;
+ enum of_gpio_flags flags;
+
+ alarm = devm_kzalloc(dev, sizeof(struct gpio_fan_alarm),
+ GFP_KERNEL);
+ if (!alarm)
+ return -ENOMEM;
+
+ val = of_get_named_gpio_flags(node, "alarm-gpios", 0, &flags);
+ if (val < 0)
+ return val;
+ alarm->gpio = val;
+ alarm->active_low = flags & OF_GPIO_ACTIVE_LOW;
+
+ pdata->alarm = alarm;
+ }
+
/* Fill GPIO pin array */
pdata->num_ctrl = of_gpio_count(node);
if (pdata->num_ctrl <= 0) {
- dev_err(dev, "gpios DT property empty / missing");
+ if (pdata->alarm)
+ return 0;
+ dev_err(dev, "DT properties empty / missing");
return -ENODEV;
}
ctrl = devm_kzalloc(dev, pdata->num_ctrl * sizeof(unsigned),
@@ -460,26 +482,6 @@ static int gpio_fan_get_of_pdata(struct device *dev,
}
pdata->speed = speed;
- /* Alarm GPIO if one exists */
- if (of_gpio_named_count(node, "alarm-gpios") > 0) {
- struct gpio_fan_alarm *alarm;
- int val;
- enum of_gpio_flags flags;
-
- alarm = devm_kzalloc(dev, sizeof(struct gpio_fan_alarm),
- GFP_KERNEL);
- if (!alarm)
- return -ENOMEM;
-
- val = of_get_named_gpio_flags(node, "alarm-gpios", 0, &flags);
- if (val < 0)
- return val;
- alarm->gpio = val;
- alarm->active_low = flags & OF_GPIO_ACTIVE_LOW;
-
- pdata->alarm = alarm;
- }
-
return 0;
}
--
2.1.1
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