(gpio-fan): Add thermal control hooks

Allow gpio-fan to be used as thermal cooling device for platforms that
use GPIO maps to control fans.

Signed-off-by: Nishanth Menon <nm@ti.com>
---

Based on v3.19-rc3

 .../devicetree/bindings/gpio/gpio-fan.txt          |   14 +++
 drivers/hwmon/gpio-fan.c                           |   93 ++++++++++++++++++--
 2 files changed, 100 insertions(+), 7 deletions(-)

On Wed, Jan 07, 2015 at 12:01:14PM -0600, Nishanth Menon wrote:
> Allow gpio-fan to be used as thermal cooling device for platforms that
> use GPIO maps to control fans.
> 
> Signed-off-by: Nishanth Menon <nm@ti.com>
> ---
> 
> Based on v3.19-rc3
> 
>  .../devicetree/bindings/gpio/gpio-fan.txt          |   14 +++
>  drivers/hwmon/gpio-fan.c                           |   93 ++++++++++++++++++--
>  2 files changed, 100 insertions(+), 7 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-fan.txt b/Documentation/devicetree/bindings/gpio/gpio-fan.txt
> index 2dd457a3469a..046f2f400dbb 100644
> --- a/Documentation/devicetree/bindings/gpio/gpio-fan.txt
> +++ b/Documentation/devicetree/bindings/gpio/gpio-fan.txt
> @@ -11,6 +11,9 @@ Required properties:
>  Optional properties:
>  - alarm-gpios: This pin going active indicates something is wrong with
>    the fan, and a udev event will be fired.
> +- cooling-cells: If used as a cooling device, must be <2>
> +  Also see: Documentation/devicetree/bindings/thermal/thermal.txt
> +  min and max states are derived from the speed-map of the fan.
>  
>  Examples:
>  
> @@ -23,3 +26,14 @@ Examples:
>  				      6000 2>;
>  		alarm-gpios = <&gpio1 15 1>;
>  	};
> +

Unnecessary second empty line.

> +	gpio_fan_cool: gpio_fan {
> +		compatible = "gpio-fan";
> +		gpios = <&gpio2 14 1
> +			 &gpio2 13 1>;
> +		gpio-fan,speed-map = <0    0
> +				      3000 1
> +				      6000 2>;
> +		alarm-gpios = <&gpio1 15 1>;
> +		#cooling-cells = <2>; /* min followed by max */
> +	};
> diff --git a/drivers/hwmon/gpio-fan.c b/drivers/hwmon/gpio-fan.c
> index 36abf814b8c7..089914c4f574 100644
> --- a/drivers/hwmon/gpio-fan.c
> +++ b/drivers/hwmon/gpio-fan.c
> @@ -34,10 +34,14 @@
>  #include <linux/of.h>
>  #include <linux/of_platform.h>
>  #include <linux/of_gpio.h>
> +#include <linux/thermal.h>
> +

Unnecessary additional empty line.

>  
>  struct gpio_fan_data {
>  	struct platform_device	*pdev;
>  	struct device		*hwmon_dev;
> +	/* Cooling device if any */
> +	struct thermal_cooling_device *cdev;
>  	struct mutex		lock; /* lock GPIOs operations. */
>  	int			num_ctrl;
>  	unsigned		*ctrl;
> @@ -387,12 +391,63 @@ static int fan_ctrl_init(struct gpio_fan_data *fan_data,
>  	return 0;
>  }
>  
> +static int gpio_fan_get_max_state(struct thermal_cooling_device *cdev,
> +				  unsigned long *state)
> +{
> +	struct gpio_fan_data *fan_data = cdev->devdata;
> +
> +	if (!fan_data)
> +		return -EINVAL;
> +
> +	*state = fan_data->num_speed - 1;
> +	return 0;
> +}
> +
> +static int gpio_fan_get_cur_state(struct thermal_cooling_device *cdev,
> +				  unsigned long *state)
> +{
> +	struct gpio_fan_data *fan_data = cdev->devdata;
> +	int r;
> +
> +	if (!fan_data)
> +		return -EINVAL;
> +
> +	r = get_fan_speed_index(fan_data);
> +	if (r < 0)
> +		return r;
> +
> +	*state = r;
> +	return 0;
> +
Unnecessary empty line.

> +}
> +
> +static int gpio_fan_set_cur_state(struct thermal_cooling_device *cdev,
> +				  unsigned long state)
> +{
> +	struct gpio_fan_data *fan_data = cdev->devdata;
> +
> +	if (!fan_data)
> +		return -EINVAL;
> +
> +	set_fan_speed(fan_data, state);
> +
> +	return 0;
> +}
> +
> +static const struct thermal_cooling_device_ops gpio_fan_cooling_ops = {
> +	.get_max_state = gpio_fan_get_max_state,
> +	.get_cur_state = gpio_fan_get_cur_state,
> +	.set_cur_state = gpio_fan_set_cur_state,
> +
Unnecessary empty line (checkpatch!!!)

> +};
> +
>  #ifdef CONFIG_OF_GPIO
>  /*
>   * Translate OpenFirmware node properties into platform_data
>   */
>  static int gpio_fan_get_of_pdata(struct device *dev,
> -			    struct gpio_fan_platform_data *pdata)
> +			         struct gpio_fan_platform_data *pdata,
> +				 struct gpio_fan_data *fan_data)
>  {
>  	struct device_node *node;
>  	struct gpio_fan_speed *speed;
> @@ -480,6 +535,12 @@ static int gpio_fan_get_of_pdata(struct device *dev,
>  		pdata->alarm = alarm;
>  	}
>  
> +	fan_data->cdev = thermal_of_cooling_device_register(node, "gpio-fan",
> +							    fan_data,
> +						    &gpio_fan_cooling_ops);

Just use one continuation line here, with no spaces up front but only tabs.

> +	if (IS_ERR(fan_data->cdev))
> +		dev_dbg(dev, "gpio-fan has no valid cooling DT property\n");
> +
The property is optional. Why does this warrant even a debug message ?

>  	return 0;
>  }
>  
> @@ -495,6 +556,11 @@ static int gpio_fan_probe(struct platform_device *pdev)
>  	struct gpio_fan_data *fan_data;
>  	struct gpio_fan_platform_data *pdata = dev_get_platdata(&pdev->dev);
>  
> +	fan_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_fan_data),
> +				GFP_KERNEL);
> +	if (!fan_data)
> +		return -ENOMEM;
> +
>  #ifdef CONFIG_OF_GPIO
>  	if (!pdata) {
>  		pdata = devm_kzalloc(&pdev->dev,
> @@ -503,20 +569,19 @@ static int gpio_fan_probe(struct platform_device *pdev)
>  		if (!pdata)
>  			return -ENOMEM;
>  
> -		err = gpio_fan_get_of_pdata(&pdev->dev, pdata);
> +		err = gpio_fan_get_of_pdata(&pdev->dev, pdata, fan_data);

It is inconsistent with the code below to call
thermal_of_cooling_device_register in gpio_fan_get_of_pdata
(and to pass fan_data just for that purpose). Please call it from here. 

>  		if (err)
>  			return err;
>  	}
>  #else /* CONFIG_OF_GPIO */
>  	if (!pdata)
>  		return -EINVAL;
> +	/* Optional cooling device register for non Device tree platforms */
> +	fan_data->cdev = thermal_cooling_device_register("gpio-fan",
> +							 fan_data,
> +							 &gpio_fan_cooling_ops);
>  #endif /* CONFIG_OF_GPIO */
>  
> -	fan_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_fan_data),
> -				GFP_KERNEL);
> -	if (!fan_data)
> -		return -ENOMEM;
> -
>  	fan_data->pdev = pdev;
>  	platform_set_drvdata(pdev, fan_data);
>  	mutex_init(&fan_data->lock);
> @@ -550,10 +615,23 @@ static int gpio_fan_probe(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +static int gpio_fan_remove(struct platform_device *pdev)
> +{
> +       struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);

Indentation is problematic. Actually, checkpatch shows several whitespace
problems as well as an unnecessary empty line. Please ensure that your patch
passes checkpatch --strict.

> +
> +	if (!IS_ERR(fan_data->cdev))
> +		thermal_cooling_device_unregister(fan_data->cdev);
> +
> +       return 0;
> +}
> +
>  static void gpio_fan_shutdown(struct platform_device *pdev)
>  {
>  	struct gpio_fan_data *fan_data = dev_get_drvdata(&pdev->dev);
>  
> +	if (!IS_ERR(fan_data->cdev))
> +		thermal_cooling_device_unregister(fan_data->cdev);
> +

Instead of having this conditional call twice, you might as well call
gpio_fan_remove() from here.

>  	if (fan_data->ctrl)
>  		set_fan_speed(fan_data, 0);
>  }
> @@ -589,6 +667,7 @@ static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
>  
>  static struct platform_driver gpio_fan_driver = {
>  	.probe		= gpio_fan_probe,
> +	.remove		= gpio_fan_remove,
>  	.shutdown	= gpio_fan_shutdown,
>  	.driver	= {
>  		.name	= "gpio-fan",
> -- 
> 1.7.9.5
> 
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