Commit 73ef85f4 authored by Simon Guinot's avatar Simon Guinot Committed by Guenter Roeck
Browse files

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: default avatarSimon Guinot <simon.guinot@sequanux.org>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 6552f327

Documentation/devicetree/bindings/gpio/gpio-fan.txt

+4 −2
Original line number Diff line number Diff line
@@ -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 {

drivers/hwmon/gpio-fan.c

+23 −21
Original line number Diff line number Diff line
@@ -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;

}

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