[lm-sensors] [PATCH 4/5] hwmon: DNS323 rev C1 fan support

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

The hardware only supports 3 settings: off, slow and fast.

In order to have a chance to work with existing fan control systems,
we emulate a PWM device with the following mapping:

   0.. 15  off		0 RPM input
  16..127  slow	      100 RPM input
 128..255  fast      2000 RPM input

This provides something more/less working with fancontrol, though
it does have a tendency to work by doing short bursts of "slow"
speed every half a minute as it settles around my min temp. Not
a big deal a specialized script could probably do better, or even
tweaks to fancontrol config. At leats it should be safe.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: lm-sensors@lm-sensors.org
---
 drivers/hwmon/Kconfig       |   12 ++
 drivers/hwmon/Makefile      |    1 +
 drivers/hwmon/dns323c-fan.c |  271 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 284 insertions(+), 0 deletions(-)
 create mode 100644 drivers/hwmon/dns323c-fan.c

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 9be8e17..5f55735 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1087,6 +1087,18 @@ config SENSORS_MC13783_ADC
         help
           Support for the A/D converter on MC13783 PMIC.
 
+config SENSORS_DNS323C_FAN
+       tristate "D-Link DNS323 rev C1 Fan"
+       depends on MACH_DNS323
+       help
+         Support for the GPIO based fan control on the D-Link DNS323
+	 HW revision C1. This exposes a pseudo pwm device with the
+	 following values supported:
+
+	 	    0..15	: Fan off
+		   16..127	: Fan on low speed
+		  128..255	: Fan on high speed
+	 
 if ACPI
 
 comment "ACPI drivers"
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 4aa1a3d..15bcdef 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -100,6 +100,7 @@ obj-$(CONFIG_SENSORS_W83L785TS)	+= w83l785ts.o
 obj-$(CONFIG_SENSORS_W83L786NG)	+= w83l786ng.o
 obj-$(CONFIG_SENSORS_WM831X)	+= wm831x-hwmon.o
 obj-$(CONFIG_SENSORS_WM8350)	+= wm8350-hwmon.o
+obj-$(CONFIG_SENSORS_DNS323C_FAN)+= dns323c-fan.o
 
 ifeq ($(CONFIG_HWMON_DEBUG_CHIP),y)
 EXTRA_CFLAGS += -DDEBUG
diff --git a/drivers/hwmon/dns323c-fan.c b/drivers/hwmon/dns323c-fan.c
new file mode 100644
index 0000000..4ae18d0
--- /dev/null
+++ b/drivers/hwmon/dns323c-fan.c
@@ -0,0 +1,271 @@
+/*
+ *  dns323c_fan - Driver for the D-LINK DNS-323 rev C1 fan control
+ *
+ *  Copyright 2010 Benjamin Herrenschmidt
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/gpio.h>
+#include <linux/hwmon.h>
+
+#include <linux/hwmon-sysfs.h>
+#include <linux/gfp.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/sysfs.h>
+#include <linux/platform_device.h>
+
+enum fan_speed {
+	FAN_OFF,
+	FAN_LOW	,
+	FAN_FAST,
+	FAN_FAST_LOCK,
+};
+
+#define DNS323C_GPIO_FAN_BIT1		18
+#define DNS323C_GPIO_FAN_BIT0		19
+
+struct dns323c_fan {
+	struct device	*hwmon;
+	struct mutex	lock;
+	enum fan_speed	speed;
+};
+
+static void __set_fan_speed(struct dns323c_fan *fan, enum fan_speed speed)
+{
+	if (speed = fan->speed)
+		return;
+
+	switch(speed) {
+	case FAN_OFF:
+		gpio_set_value(DNS323C_GPIO_FAN_BIT1, 0);
+		gpio_set_value(DNS323C_GPIO_FAN_BIT0, 0);
+		break;
+	case FAN_LOW:
+		gpio_set_value(DNS323C_GPIO_FAN_BIT1, 0);
+		gpio_set_value(DNS323C_GPIO_FAN_BIT0, 1);
+		break;
+	default:
+		gpio_set_value(DNS323C_GPIO_FAN_BIT0, 0);
+		gpio_set_value(DNS323C_GPIO_FAN_BIT1, 1);
+	};
+	fan->speed = speed;
+}
+
+static ssize_t show_name(struct device *dev, struct device_attribute *da,
+			   char *buf)
+{
+	return sprintf(buf, "dns323c-fan\n");
+}
+
+static ssize_t show_pwm(struct device *dev, struct device_attribute *da,
+			char *buf)
+{
+	struct dns323c_fan *fan = dev_get_drvdata(dev);
+	int pseudo_pwm;
+
+	switch(fan->speed) {
+	case FAN_OFF:
+		pseudo_pwm = 0;
+		break;
+	case FAN_LOW:
+		pseudo_pwm = 63;
+		break;
+	default:
+		pseudo_pwm = 255;
+	}
+	return sprintf(buf, "%d\n", pseudo_pwm);
+}
+
+static ssize_t set_pwm(struct device *dev, struct device_attribute *da,
+		       const char *buf, size_t count)
+{
+	struct dns323c_fan *fan = dev_get_drvdata(dev);
+	enum fan_speed speed;
+	unsigned long val;
+
+	if (strict_strtoul(buf, 10, &val))
+		return -EINVAL;
+	if (fan->speed = FAN_FAST_LOCK)
+		return count;
+
+	mutex_lock(&fan->lock);
+	if (val < 16)
+		speed = FAN_OFF;
+	else if (val < 128)
+		speed = FAN_LOW;
+	else
+		speed = FAN_FAST;
+	__set_fan_speed(fan, speed);
+	mutex_unlock(&fan->lock);
+
+	return count;
+}
+
+static ssize_t show_pwm_en(struct device *dev, struct device_attribute *da,
+			   char *buf)
+{
+	struct dns323c_fan *fan = dev_get_drvdata(dev);
+
+	if (fan->speed = FAN_FAST_LOCK)
+		return sprintf(buf, "0\n");
+	else
+		return sprintf(buf, "1\n");
+}
+
+static ssize_t set_pwm_en(struct device *dev, struct device_attribute *da,
+			  const char *buf, size_t count)
+{
+	struct dns323c_fan *fan = dev_get_drvdata(dev);
+	enum fan_speed speed;
+	unsigned long val;
+
+	if (strict_strtoul(buf, 10, &val))
+		return -EINVAL;
+	if (val != 0 && val != 1)
+		return -EINVAL;
+
+	mutex_lock(&fan->lock);
+	if (val = 0 && fan->speed != FAN_FAST_LOCK)
+		speed = FAN_FAST_LOCK;
+	else if (val != 0 && fan->speed = FAN_FAST_LOCK)
+		speed = FAN_FAST;
+	else
+		speed = fan->speed;
+	__set_fan_speed(fan, speed);
+	mutex_unlock(&fan->lock);
+
+	return count;
+}
+
+static ssize_t show_fake_rpm(struct device *dev, struct device_attribute *da,
+			     char *buf)
+{
+	struct dns323c_fan *fan = dev_get_drvdata(dev);
+	int pseudo_rpm;
+
+	switch(fan->speed) {
+	case FAN_OFF:
+		pseudo_rpm = 0;
+		break;
+	case FAN_LOW:
+		pseudo_rpm = 400;
+		break;
+	default:
+		pseudo_rpm = 2000;
+	}
+	return sprintf(buf, "%d\n", pseudo_rpm);
+}
+
+static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
+static DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm);
+static DEVICE_ATTR(pwm1_enable, S_IRUGO | S_IWUSR, show_pwm_en, set_pwm_en);
+static DEVICE_ATTR(fan1_input, S_IRUGO, show_fake_rpm, NULL);
+
+static int dns323c_fan_probe(struct platform_device *pdev)
+{
+	struct dns323c_fan *fan = NULL;
+	int ret = -ENXIO;
+
+	/* Get the GPIOs */
+	if (gpio_request(DNS323C_GPIO_FAN_BIT0, "FAN0") != 0) {
+		pr_err("dns323c_fan: Failed to request fan GPIO 0 !\n");
+		return -ENXIO;
+	}
+	if (gpio_request(DNS323C_GPIO_FAN_BIT1, "FAN1") != 0) {
+		pr_err("dns323c_fan: Failed to request fan GPIO 1 !\n");
+		goto err_gpio;
+	}
+
+	/* Set directions to output and medium speed. We write bit 1 first
+	 * since it contains 0 to avoid having a transitory 11 state which
+	 * isn't supported
+	 */
+	gpio_direction_output(DNS323C_GPIO_FAN_BIT1, 0);
+	gpio_direction_output(DNS323C_GPIO_FAN_BIT0, 1);
+
+	/* Grab some memory for our state */
+	fan = kzalloc(sizeof(struct dns323c_fan), GFP_KERNEL);
+	if (!fan) {
+		ret = -ENOMEM;
+		goto err_alloc;
+	}
+	fan->speed = FAN_LOW;
+	mutex_init(&fan->lock);
+	platform_set_drvdata(pdev, fan);
+
+	ret = device_create_file(&pdev->dev, &dev_attr_name);
+	ret |= device_create_file(&pdev->dev, &dev_attr_pwm1);
+	ret |= device_create_file(&pdev->dev, &dev_attr_pwm1_enable);
+	ret |= device_create_file(&pdev->dev, &dev_attr_fan1_input);
+	if (ret)
+		goto err_file;
+
+	fan->hwmon = hwmon_device_register(&pdev->dev);
+	if (IS_ERR(fan->hwmon)) {
+		ret = PTR_ERR(fan->hwmon);
+		goto err_dev;
+	}
+	return 0;
+
+ err_dev:
+	device_remove_file(&pdev->dev, &dev_attr_name);
+	device_remove_file(&pdev->dev, &dev_attr_pwm1);
+	device_remove_file(&pdev->dev, &dev_attr_pwm1_enable);
+	device_remove_file(&pdev->dev, &dev_attr_fan1_input);
+ err_file:
+	kfree(fan);
+ err_alloc:
+	gpio_free(DNS323C_GPIO_FAN_BIT1);
+ err_gpio:
+	gpio_free(DNS323C_GPIO_FAN_BIT0);
+	return ret;
+}
+
+static int __devexit dns323c_fan_remove(struct platform_device *pdev)
+{
+	struct dns323c_fan *fan = platform_get_drvdata(pdev);
+
+	hwmon_device_unregister(fan->hwmon);
+	device_remove_file(&pdev->dev, &dev_attr_name);
+	device_remove_file(&pdev->dev, &dev_attr_pwm1);
+	device_remove_file(&pdev->dev, &dev_attr_pwm1_enable);
+	device_remove_file(&pdev->dev, &dev_attr_fan1_input);
+	kfree(fan);
+	gpio_free(DNS323C_GPIO_FAN_BIT1);
+	gpio_free(DNS323C_GPIO_FAN_BIT0);
+	return 0;
+}
+
+static struct platform_driver dns323c_fan_driver = {
+	.probe = dns323c_fan_probe,
+	.remove = __devexit_p(dns323c_fan_remove),
+	.driver = {
+		.name = "dns323c-fan",
+		.owner = THIS_MODULE,
+	},
+};
+
+static int __init dns323c_fan_init(void)
+{
+	return platform_driver_register(&dns323c_fan_driver);
+}
+
+static void __exit dns323c_fan_exit(void)
+{
+	platform_driver_unregister(&dns323c_fan_driver);
+}
+
+MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
+MODULE_DESCRIPTION("DNS323 RevC1 Fan control");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:dns323c-fan");
+
+module_init(dns323c_fan_init);
+module_exit(dns323c_fan_exit);



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