hwmon: (aspeed-pwm-tacho) cooling device support.

Add support in aspeed-pwm-tacho driver for cooling device creation.
This cooling device could be bound to a thermal zone
for the thermal control. Device will appear in /sys/class/thermal
folder as cooling_deviceX. Then it could be bound to particular
thermal zones. Allow specification of the cooling levels
vector - PWM duty cycle values in a range from 0 to 255
which correspond to thermal cooling states.

Signed-off-by: Mykola Kostenok <c_mykolak@mellanox.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

1 files changed, 114 insertions, 2 deletions

diff --git a/drivers/hwmon/aspeed-pwm-tacho.c b/drivers/hwmon/aspeed-pwm-tacho.c
index ddfe66bdff86..69b97d45e3cb 100644
--- a/drivers/hwmon/aspeed-pwm-tacho.c
+++ b/drivers/hwmon/aspeed-pwm-tacho.c
@@ -20,6 +20,7 @@
 #include <linux/platform_device.h>
 #include <linux/sysfs.h>
 #include <linux/regmap.h>
+#include <linux/thermal.h>
 
 /* ASPEED PWM & FAN Tach Register Definition */
 #define ASPEED_PTCR_CTRL                0x00
@@ -166,6 +167,18 @@
 /* How long we sleep in us while waiting for an RPM result. */
 #define ASPEED_RPM_STATUS_SLEEP_USEC    500
 
+#define MAX_CDEV_NAME_LEN 16
+
+struct aspeed_cooling_device {
+        char name[16];
+        struct aspeed_pwm_tacho_data *priv;
+        struct thermal_cooling_device *tcdev;
+        int pwm_port;
+        u8 *cooling_levels;
+        u8 max_state;
+        u8 cur_state;
+};
+
 struct aspeed_pwm_tacho_data {
         struct regmap *regmap;
         unsigned long clk_freq;
@@ -180,6 +193,7 @@ struct aspeed_pwm_tacho_data {
         u8 pwm_port_type[8];
         u8 pwm_port_fan_ctrl[8];
         u8 fan_tach_ch_source[16];
+        struct aspeed_cooling_device *cdev[8];
         const struct attribute_group *groups[3];
 };
 
@@ -765,6 +779,94 @@ static void aspeed_create_fan_tach_channel(struct aspeed_pwm_tacho_data *priv,
         }
 }
 
+static int
+aspeed_pwm_cz_get_max_state(struct thermal_cooling_device *tcdev,
+                            unsigned long *state)
+{
+        struct aspeed_cooling_device *cdev = tcdev->devdata;
+
+        *state = cdev->max_state;
+
+        return 0;
+}
+
+static int
+aspeed_pwm_cz_get_cur_state(struct thermal_cooling_device *tcdev,
+                            unsigned long *state)
+{
+        struct aspeed_cooling_device *cdev = tcdev->devdata;
+
+        *state = cdev->cur_state;
+
+        return 0;
+}
+
+static int
+aspeed_pwm_cz_set_cur_state(struct thermal_cooling_device *tcdev,
+                            unsigned long state)
+{
+        struct aspeed_cooling_device *cdev = tcdev->devdata;
+
+        if (state > cdev->max_state)
+                return -EINVAL;
+
+        cdev->cur_state = state;
+        cdev->priv->pwm_port_fan_ctrl[cdev->pwm_port] =
+                                        cdev->cooling_levels[cdev->cur_state];
+        aspeed_set_pwm_port_fan_ctrl(cdev->priv, cdev->pwm_port,
+                                     cdev->cooling_levels[cdev->cur_state]);
+
+        return 0;
+}
+
+static const struct thermal_cooling_device_ops aspeed_pwm_cool_ops = {
+        .get_max_state = aspeed_pwm_cz_get_max_state,
+        .get_cur_state = aspeed_pwm_cz_get_cur_state,
+        .set_cur_state = aspeed_pwm_cz_set_cur_state,
+};
+
+static int aspeed_create_pwm_cooling(struct device *dev,
+                                     struct device_node *child,
+                                     struct aspeed_pwm_tacho_data *priv,
+                                     u32 pwm_port, u8 num_levels)
+{
+        int ret;
+        struct aspeed_cooling_device *cdev;
+
+        cdev = devm_kzalloc(dev, sizeof(*cdev), GFP_KERNEL);
+
+        if (!cdev)
+                return -ENOMEM;
+
+        cdev->cooling_levels = devm_kzalloc(dev, num_levels, GFP_KERNEL);
+        if (!cdev->cooling_levels)
+                return -ENOMEM;
+
+        cdev->max_state = num_levels - 1;
+        ret = of_property_read_u8_array(child, "cooling-levels",
+                                        cdev->cooling_levels,
+                                        num_levels);
+        if (ret) {
+                dev_err(dev, "Property 'cooling-levels' cannot be read.\n");
+                return ret;
+        }
+        snprintf(cdev->name, MAX_CDEV_NAME_LEN, "%s%d", child->name, pwm_port);
+
+        cdev->tcdev = thermal_of_cooling_device_register(child,
+                                                         cdev->name,
+                                                         cdev,
+                                                         &aspeed_pwm_cool_ops);
+        if (IS_ERR(cdev->tcdev))
+                return PTR_ERR(cdev->tcdev);
+
+        cdev->priv = priv;
+        cdev->pwm_port = pwm_port;
+
+        priv->cdev[pwm_port] = cdev;
+
+        return 0;
+}
+
 static int aspeed_create_fan(struct device *dev,
                              struct device_node *child,
                              struct aspeed_pwm_tacho_data *priv)
@@ -778,6 +880,15 @@ static int aspeed_create_fan(struct device *dev,
                 return ret;
         aspeed_create_pwm_port(priv, (u8)pwm_port);
 
+        ret = of_property_count_u8_elems(child, "cooling-levels");
+
+        if (ret > 0) {
+                ret = aspeed_create_pwm_cooling(dev, child, priv, pwm_port,
+                                                ret);
+                if (ret)
+                        return ret;
+        }
+
         count = of_property_count_u8_elems(child, "aspeed,fan-tach-ch");
         if (count < 1)
                 return -EINVAL;
@@ -834,9 +945,10 @@ static int aspeed_pwm_tacho_probe(struct platform_device *pdev)
 
         for_each_child_of_node(np, child) {
                 ret = aspeed_create_fan(dev, child, priv);
-                of_node_put(child);
-                if (ret)
+                if (ret) {
+                        of_node_put(child);
                         return ret;
+                }
         }
 
         priv->groups[0] = &pwm_dev_group;