[PATCH 1/2] hwmon: Add devicetree bindings to gpio-fan
Jamie Lentin
jm at lentin.co.uk
Sat Sep 8 02:34:34 EST 2012
Allow a gpio-fan to be defined in devicetree, see binding documentation
for details.
Signed-off-by: Jamie Lentin <jm at lentin.co.uk>
---
.../devicetree/bindings/gpio/gpio-fan.txt | 25 +++++
drivers/hwmon/gpio-fan.c | 111 ++++++++++++++++++++
2 files changed, 136 insertions(+)
create mode 100644 Documentation/devicetree/bindings/gpio/gpio-fan.txt
diff --git a/Documentation/devicetree/bindings/gpio/gpio-fan.txt b/Documentation/devicetree/bindings/gpio/gpio-fan.txt
new file mode 100644
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..876ce41 100644
--- 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;
@@ -400,12 +402,120 @@ static ssize_t show_name(struct device *dev,
static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
+
+#ifdef CONFIG_OF
+/*
+ * 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);
+ ctrl = devm_kzalloc(dev, pdata->num_ctrl * sizeof(unsigned),
+ GFP_KERNEL);
+ if (!ctrl)
+ return -ENOMEM;
+ for (i = 0; i < of_gpio_count(node); i++) {
+ int val;
+
+ val = of_get_gpio(node, i);
+ if (val >= 0)
+ ctrl[i] = val;
+ else
+ return -EINVAL;
+ }
+ pdata->ctrl = ctrl;
+
+ /* Get speed map array size */
+ i = 0;
+ of_property_for_each_u32(node, "gpio-fan,speed-map", prop, p, u)
+ i++;
+ if (i & 1) {
+ dev_err(dev, "gpio-fan,speed-map contains odd number of entries");
+ return -ENODEV;
+ }
+ pdata->num_speed = i >> 1;
+ speed = devm_kzalloc(dev,
+ pdata->num_speed * sizeof(struct gpio_fan_speed),
+ GFP_KERNEL);
+ if (!speed)
+ return -ENOMEM;
+
+ /* Populate speed map */
+ i = 0;
+ of_property_for_each_u32(node, "gpio-fan,speed-map", prop, p, u) {
+ if (i & 1)
+ speed[i >> 1].ctrl_val = (int)u;
+ else
+ speed[i >> 1].rpm = (int)u;
+ i++;
+ }
+ 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) {
+ alarm->gpio = val;
+ alarm->active_low = flags & OF_GPIO_ACTIVE_LOW;
+ } else
+ return -EINVAL;
+
+ pdata->alarm = alarm;
+ }
+
+ return 0;
+}
+
+static const struct of_device_id of_gpio_fan_match[] = {
+ { .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
+ if (!pdata) {
+ struct gpio_fan_platform_data *alt_pdata;
+
+ alt_pdata = devm_kzalloc(&pdev->dev,
+ sizeof(struct gpio_fan_platform_data),
+ GFP_KERNEL);
+ if (!alt_pdata)
+ return -ENOMEM;
+
+ err = gpio_fan_get_of_pdata(&pdev->dev, alt_pdata);
+ if (err)
+ return err;
+ pdata = alt_pdata;
+ }
+#endif /* CONFIG_OF_GPIO */
+
if (!pdata)
return -EINVAL;
@@ -511,6 +621,7 @@ 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),
},
};
--
1.7.10.4
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