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hwmon: (gpio-fan) allow to use alarm support alone from DT

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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@sequanux.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Simon Guinot 2015-02-25 18:58:19 +01:00 committed by Guenter Roeck
parent 6552f327ca
commit 73ef85f42d
2 changed files with 27 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
Documentation/devicetree/bindings/gpio/gpio-fan.txt
View File

@ -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 {

44
drivers/hwmon/gpio-fan.c
View File

@ -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;
}