hwmon: add generic GPIO fan driver

This patch adds hwmon support for fans connected to GPIO lines.

Platform specific information such as GPIO pinout and speed conversion array
(rpm from/to GPIO value) are passed to the driver via platform_data.

Signed-off-by: Simon Guinot <sguinot@lacie.com>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/include/linux/gpio-fan.h b/include/linux/gpio-fan.h
new file mode 100644
index 000000000000..096659169215
--- /dev/null
+++ b/include/linux/gpio-fan.h
@@ -0,0 +1,36 @@
+/*
+ * include/linux/gpio-fan.h
+ *
+ * Platform data structure for GPIO fan driver
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#ifndef __LINUX_GPIO_FAN_H
+#define __LINUX_GPIO_FAN_H
+
+struct gpio_fan_alarm {
+        unsigned        gpio;
+        unsigned        active_low;
+};
+
+struct gpio_fan_speed {
+        int rpm;
+        int ctrl_val;
+};
+
+struct gpio_fan_platform_data {
+        int                     num_ctrl;
+        unsigned                *ctrl;  /* fan control GPIOs. */
+        struct gpio_fan_alarm   *alarm; /* fan alarm GPIO. */
+        /*
+         * Speed conversion array: rpm from/to GPIO bit field.
+         * This array _must_ be sorted in ascending rpm order.
+         */
+        int                     num_speed;
+        struct gpio_fan_speed   *speed;
+};
+
+#endif /* __LINUX_GPIO_FAN_H */