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

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>
wifi-calibration
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;
}