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Date: Wed, 25 Feb 2015 16:34:22 +0100
From: Lukasz Majewski <l.majewski@...sung.com>
To: Eduardo Valentin <edubezval@...il.com>,
Kamil Debski <k.debski@...sung.com>,
Jean Delvare <jdelvare@...e.de>,
Guenter Roeck <linux@...ck-us.net>,
Kukjin Kim <kgene@...nel.org>
Cc: lm-sensors@...sensors.org,
Linux PM list <linux-pm@...r.kernel.org>,
"linux-samsung-soc@...r.kernel.org"
<linux-samsung-soc@...r.kernel.org>, devicetree@...r.kernel.org,
Lukasz Majewski <l.majewski@...ess.pl>,
Kukjin Kim <kgene.kim@...sung.com>,
linux-kernel@...r.kernel.org,
Sjoerd Simons <sjoerd.simons@...labora.co.uk>,
Abhilash Kesavan <kesavan.abhilash@...il.com>,
Abhilash Kesavan <a.kesavan@...sung.com>,
Lukasz Majewski <l.majewski@...sung.com>
Subject: [PATCH v5 6/6] hwmon: pwm-fan: Code for using PWM FAN as a cooling
device
The PWM FAN device can now be used as a thermal cooling device. Necessary
infrastructure has been added in this commit.
Signed-off-by: Lukasz Majewski <l.majewski@...sung.com>
---
Changes for v2:
- Replace pwm_fan_cooling_states with pwm_fan_cooling_levels
- Update ctx->pwm_fan_state when correct data from device tree is available
- Using therma_cdev_update() when thermal is ready for controlling the fan
Changes for v3:
- Rename patch heading
- pwm_fan_of_get_cooling_data() now returns -EINVAL when no "cooling-levels"
property defined
- register of cooling device only when proper cooling data is present
Changes for v4:
- None
Changes for v5:
- Check for IS_ENABLED(CONFIG_THERMAL) has been added to prevent from
executing thermal_* specific functions
---
drivers/hwmon/pwm-fan.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 82 insertions(+), 1 deletion(-)
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index e6ed353..2c1a8f0 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -24,6 +24,7 @@
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/sysfs.h>
+#include <linux/thermal.h>
#define MAX_PWM 255
@@ -68,6 +69,17 @@ exit_set_pwm_err:
return ret;
}
+static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm)
+{
+ int i;
+
+ for (i = 0; i < ctx->pwm_fan_max_state; ++i)
+ if (pwm < ctx->pwm_fan_cooling_levels[i + 1])
+ break;
+
+ ctx->pwm_fan_state = i;
+}
+
static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
@@ -82,6 +94,7 @@ static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
if (ret)
return ret;
+ pwm_fan_update_state(ctx, pwm);
return count;
}
@@ -103,6 +116,59 @@ static struct attribute *pwm_fan_attrs[] = {
ATTRIBUTE_GROUPS(pwm_fan);
+/* thermal cooling device callbacks */
+static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev,
+ unsigned long *state)
+{
+ struct pwm_fan_ctx *ctx = cdev->devdata;
+
+ *state = ctx->pwm_fan_max_state;
+
+ return 0;
+}
+
+static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev,
+ unsigned long *state)
+{
+ struct pwm_fan_ctx *ctx = cdev->devdata;
+
+ if (!ctx)
+ return -EINVAL;
+
+ *state = ctx->pwm_fan_state;
+
+ return 0;
+}
+
+static int
+pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
+{
+ struct pwm_fan_ctx *ctx = cdev->devdata;
+ int ret;
+
+ if (!ctx || (state > ctx->pwm_fan_max_state))
+ return -EINVAL;
+
+ if (state == ctx->pwm_fan_state)
+ return 0;
+
+ ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]);
+ if (ret) {
+ dev_err(&cdev->device, "Cannot set pwm!\n");
+ return ret;
+ }
+
+ ctx->pwm_fan_state = state;
+
+ return ret;
+}
+
+static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = {
+ .get_max_state = pwm_fan_get_max_state,
+ .get_cur_state = pwm_fan_get_cur_state,
+ .set_cur_state = pwm_fan_set_cur_state,
+};
+
int pwm_fan_of_get_cooling_data(struct device *dev, struct pwm_fan_ctx *ctx)
{
struct device_node *np = dev->of_node;
@@ -145,8 +211,9 @@ int pwm_fan_of_get_cooling_data(struct device *dev, struct pwm_fan_ctx *ctx)
static int pwm_fan_probe(struct platform_device *pdev)
{
- struct device *hwmon;
+ struct thermal_cooling_device *cdev;
struct pwm_fan_ctx *ctx;
+ struct device *hwmon;
int duty_cycle;
int ret;
@@ -193,6 +260,20 @@ static int pwm_fan_probe(struct platform_device *pdev)
if (ret)
return ret;
+ ctx->pwm_fan_state = ctx->pwm_fan_max_state;
+ if (IS_ENABLED(CONFIG_THERMAL)) {
+ cdev = thermal_of_cooling_device_register(pdev->dev.of_node,
+ "pwm-fan", ctx,
+ &pwm_fan_cooling_ops);
+ if (IS_ERR(cdev)) {
+ dev_err(&pdev->dev,
+ "Failed to register pwm-fan as cooling device");
+ pwm_disable(ctx->pwm);
+ return PTR_ERR(cdev);
+ }
+ thermal_cdev_update(cdev);
+ }
+
return 0;
}
--
2.0.0.rc2
--
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