hwmon: Add devicetree bindings to gpio-fan

Allow a gpio-fan to be defined in devicetree, see binding documentation
for details.

Signed-off-by: Jamie Lentin <jm@lentin.co.uk>
Acked-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

diff --git a/Documentation/devicetree/bindings/gpio/gpio-fan.txt b/Documentation/devicetree/bindings/gpio/gpio-fan.txt
new file mode 100644 (file)
index 0000000..2dd457a
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-fan.txt
@@ -0,0 +1,25 @@
+Bindings for fan connected to GPIO lines
+
+Required properties:
+- compatible : "gpio-fan"
+- 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.
+
+Examples:
+
+       gpio_fan {
+               compatible = "gpio-fan";
+               gpios = <&gpio1 14 1
+                        &gpio1 13 1>;
+               gpio-fan,speed-map = <0    0
+                                     3000 1
+                                     6000 2>;
+               alarm-gpios = <&gpio1 15 1>;
+       };

diff --git a/drivers/hwmon/gpio-fan.c b/drivers/hwmon/gpio-fan.c
index 2f4b01b..36509ae 100644 (file)
--- a/drivers/hwmon/gpio-fan.c
+++ b/drivers/hwmon/gpio-fan.c
@@ -31,6 +31,8 @@
 #include <linux/hwmon.h>
 #include <linux/gpio.h>
 #include <linux/gpio-fan.h>
+#include <linux/of_platform.h>
+#include <linux/of_gpio.h>
 
 struct gpio_fan_data {
        struct platform_device  *pdev;
@@ -400,14 +402,131 @@ static ssize_t show_name(struct device *dev,
 
 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 
+
+#ifdef CONFIG_OF_GPIO
+/*
+ * Translate OpenFirmware node properties into platform_data
+ */
+static int gpio_fan_get_of_pdata(struct device *dev,
+                           struct gpio_fan_platform_data *pdata)
+{
+       struct device_node *node;
+       struct gpio_fan_speed *speed;
+       unsigned *ctrl;
+       unsigned i;
+       u32 u;
+       struct property *prop;
+       const __be32 *p;
+
+       node = dev->of_node;
+
+       /* Fill GPIO pin array */
+       pdata->num_ctrl = of_gpio_count(node);
+       if (!pdata->num_ctrl) {
+               dev_err(dev, "gpios DT property empty / missing");
+               return -ENODEV;
+       }
+       ctrl = devm_kzalloc(dev, pdata->num_ctrl * sizeof(unsigned),
+                               GFP_KERNEL);
+       if (!ctrl)
+               return -ENOMEM;
+       for (i = 0; i < pdata->num_ctrl; i++) {
+               int val;
+
+               val = of_get_gpio(node, i);
+               if (val < 0)
+                       return val;
+               ctrl[i] = val;
+       }
+       pdata->ctrl = ctrl;
+
+       /* Get number of RPM/ctrl_val pairs in speed map */
+       prop = of_find_property(node, "gpio-fan,speed-map", &i);
+       if (!prop) {
+               dev_err(dev, "gpio-fan,speed-map DT property missing");
+               return -ENODEV;
+       }
+       i = i / sizeof(u32);
+       if (i == 0 || i & 1) {
+               dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries");
+               return -ENODEV;
+       }
+       pdata->num_speed = i / 2;
+
+       /*
+        * Populate speed map
+        * Speed map is in the form <RPM ctrl_val RPM ctrl_val ...>
+        * this needs splitting into pairs to create gpio_fan_speed structs
+        */
+       speed = devm_kzalloc(dev,
+                       pdata->num_speed * sizeof(struct gpio_fan_speed),
+                       GFP_KERNEL);
+       if (!speed)
+               return -ENOMEM;
+       p = NULL;
+       for (i = 0; i < pdata->num_speed; i++) {
+               p = of_prop_next_u32(prop, p, &u);
+               if (!p)
+                       return -ENODEV;
+               speed[i].rpm = u;
+               p = of_prop_next_u32(prop, p, &u);
+               if (!p)
+                       return -ENODEV;
+               speed[i].ctrl_val = u;
+       }
+       pdata->speed = speed;
+
+       /* Alarm GPIO if one exists */
+       if (of_gpio_named_count(node, "alarm-gpios")) {
+               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;
+}
+
+static struct of_device_id of_gpio_fan_match[] __devinitdata = {
+       { .compatible = "gpio-fan", },
+       {},
+};
+#endif /* CONFIG_OF_GPIO */
+
 static int __devinit gpio_fan_probe(struct platform_device *pdev)
 {
        int err;
        struct gpio_fan_data *fan_data;
        struct gpio_fan_platform_data *pdata = pdev->dev.platform_data;
 
+#ifdef CONFIG_OF_GPIO
+       if (!pdata) {
+               pdata = devm_kzalloc(&pdev->dev,
+                                       sizeof(struct gpio_fan_platform_data),
+                                       GFP_KERNEL);
+               if (!pdata)
+                       return -ENOMEM;
+
+               err = gpio_fan_get_of_pdata(&pdev->dev, pdata);
+               if (err)
+                       return err;
+       }
+#else /* CONFIG_OF_GPIO */
        if (!pdata)
                return -EINVAL;
+#endif /* CONFIG_OF_GPIO */
 
        fan_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_fan_data),
                                GFP_KERNEL);
@@ -511,6 +630,7 @@ static struct platform_driver gpio_fan_driver = {
        .driver = {
                .name   = "gpio-fan",
                .pm     = GPIO_FAN_PM,
+               .of_match_table = of_match_ptr(of_gpio_fan_match),
        },
 };