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Date:	Wed, 19 Dec 2012 17:02:54 +0000
From:	Grant Likely <grant.likely@...retlab.ca>
To:	Peter Ujfalusi <peter.ujfalusi@...com>,
	Linus Walleij <linus.walleij@...aro.org>
Cc:	linux-kernel@...r.kernel.org, linux-omap@...r.kernel.org
Subject: Re: [PATCH v2 1/3] gpio: twl4030: Introduce private structure to store variables needed runtime

On Thu, 6 Dec 2012 11:52:05 +0100, Peter Ujfalusi <peter.ujfalusi@...com> wrote:
> Move most of the global variables inside a private structure and allocate
> it dynamically.
> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@...com>

Applied, thanks

g.

> ---
>  drivers/gpio/gpio-twl4030.c | 82 +++++++++++++++++++++++++++------------------
>  1 file changed, 50 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/gpio/gpio-twl4030.c b/drivers/gpio/gpio-twl4030.c
> index 55b4fe4..c092739 100644
> --- a/drivers/gpio/gpio-twl4030.c
> +++ b/drivers/gpio/gpio-twl4030.c
> @@ -49,11 +49,6 @@
>   * There are also two LED pins used sometimes as output-only GPIOs.
>   */
>  
> -
> -static struct gpio_chip twl_gpiochip;
> -static int twl4030_gpio_base;
> -static int twl4030_gpio_irq_base;
> -
>  /* genirq interfaces are not available to modules */
>  #ifdef MODULE
>  #define is_module()	true
> @@ -72,11 +67,20 @@ static int twl4030_gpio_irq_base;
>  /* Data structures */
>  static DEFINE_MUTEX(gpio_lock);
>  
> -/* store usage of each GPIO. - each bit represents one GPIO */
> -static unsigned int gpio_usage_count;
> +struct gpio_twl4030_priv {
> +	struct gpio_chip gpio_chip;
> +	int irq_base;
> +
> +	unsigned int usage_count;
> +};
>  
>  /*----------------------------------------------------------------------*/
>  
> +static inline struct gpio_twl4030_priv *to_gpio_twl4030(struct gpio_chip *chip)
> +{
> +	return container_of(chip, struct gpio_twl4030_priv, gpio_chip);
> +}
> +
>  /*
>   * To configure TWL4030 GPIO module registers
>   */
> @@ -193,10 +197,6 @@ static int twl4030_get_gpio_datain(int gpio)
>  	u8 base = 0;
>  	int ret = 0;
>  
> -	if (unlikely((gpio >= TWL4030_GPIO_MAX)
> -		|| !(gpio_usage_count & BIT(gpio))))
> -		return -EPERM;
> -
>  	base = REG_GPIODATAIN1 + d_bnk;
>  	ret = gpio_twl4030_read(base);
>  	if (ret > 0)
> @@ -209,6 +209,7 @@ static int twl4030_get_gpio_datain(int gpio)
>  
>  static int twl_request(struct gpio_chip *chip, unsigned offset)
>  {
> +	struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip);
>  	int status = 0;
>  
>  	mutex_lock(&gpio_lock);
> @@ -252,7 +253,7 @@ static int twl_request(struct gpio_chip *chip, unsigned offset)
>  	}
>  
>  	/* on first use, turn GPIO module "on" */
> -	if (!gpio_usage_count) {
> +	if (!priv->usage_count) {
>  		struct twl4030_gpio_platform_data *pdata;
>  		u8 value = MASK_GPIO_CTRL_GPIO_ON;
>  
> @@ -266,16 +267,18 @@ static int twl_request(struct gpio_chip *chip, unsigned offset)
>  		status = gpio_twl4030_write(REG_GPIO_CTRL, value);
>  	}
>  
> +done:
>  	if (!status)
> -		gpio_usage_count |= (0x1 << offset);
> +		priv->usage_count |= BIT(offset);
>  
> -done:
>  	mutex_unlock(&gpio_lock);
>  	return status;
>  }
>  
>  static void twl_free(struct gpio_chip *chip, unsigned offset)
>  {
> +	struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip);
> +
>  	if (offset >= TWL4030_GPIO_MAX) {
>  		twl4030_led_set_value(offset - TWL4030_GPIO_MAX, 1);
>  		return;
> @@ -283,10 +286,10 @@ static void twl_free(struct gpio_chip *chip, unsigned offset)
>  
>  	mutex_lock(&gpio_lock);
>  
> -	gpio_usage_count &= ~BIT(offset);
> +	priv->usage_count &= ~BIT(offset);
>  
>  	/* on last use, switch off GPIO module */
> -	if (!gpio_usage_count)
> +	if (!priv->usage_count)
>  		gpio_twl4030_write(REG_GPIO_CTRL, 0x0);
>  
>  	mutex_unlock(&gpio_lock);
> @@ -301,14 +304,19 @@ static int twl_direction_in(struct gpio_chip *chip, unsigned offset)
>  
>  static int twl_get(struct gpio_chip *chip, unsigned offset)
>  {
> +	struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip);
>  	int status = 0;
>  
> +	if (!(priv->usage_count & BIT(offset)))
> +		return -EPERM;
> +
>  	if (offset < TWL4030_GPIO_MAX)
>  		status = twl4030_get_gpio_datain(offset);
>  	else if (offset == TWL4030_GPIO_MAX)
>  		status = cached_leden & LEDEN_LEDAON;
>  	else
>  		status = cached_leden & LEDEN_LEDBON;
> +
>  	return (status < 0) ? 0 : status;
>  }
>  
> @@ -333,12 +341,14 @@ static void twl_set(struct gpio_chip *chip, unsigned offset, int value)
>  
>  static int twl_to_irq(struct gpio_chip *chip, unsigned offset)
>  {
> -	return (twl4030_gpio_irq_base && (offset < TWL4030_GPIO_MAX))
> -		? (twl4030_gpio_irq_base + offset)
> +	struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip);
> +
> +	return (priv->irq_base && (offset < TWL4030_GPIO_MAX))
> +		? (priv->irq_base + offset)
>  		: -EINVAL;
>  }
>  
> -static struct gpio_chip twl_gpiochip = {
> +static struct gpio_chip template_chip = {
>  	.label			= "twl4030",
>  	.owner			= THIS_MODULE,
>  	.request		= twl_request,
> @@ -424,8 +434,14 @@ static int __devinit gpio_twl4030_probe(struct platform_device *pdev)
>  {
>  	struct twl4030_gpio_platform_data *pdata = pdev->dev.platform_data;
>  	struct device_node *node = pdev->dev.of_node;
> +	struct gpio_twl4030_priv *priv;
>  	int ret, irq_base;
>  
> +	priv = devm_kzalloc(&pdev->dev, sizeof(struct gpio_twl4030_priv),
> +			    GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
>  	/* maybe setup IRQs */
>  	if (is_module()) {
>  		dev_err(&pdev->dev, "can't dispatch IRQs from modules\n");
> @@ -445,12 +461,13 @@ static int __devinit gpio_twl4030_probe(struct platform_device *pdev)
>  	if (ret < 0)
>  		return ret;
>  
> -	twl4030_gpio_irq_base = irq_base;
> +	priv->irq_base = irq_base;
>  
>  no_irqs:
> -	twl_gpiochip.base = -1;
> -	twl_gpiochip.ngpio = TWL4030_GPIO_MAX;
> -	twl_gpiochip.dev = &pdev->dev;
> +	priv->gpio_chip = template_chip;
> +	priv->gpio_chip.base = -1;
> +	priv->gpio_chip.ngpio = TWL4030_GPIO_MAX;
> +	priv->gpio_chip.dev = &pdev->dev;
>  
>  	if (node)
>  		pdata = of_gpio_twl4030(&pdev->dev);
> @@ -481,23 +498,23 @@ no_irqs:
>  	 * is (still) clear if use_leds is set.
>  	 */
>  	if (pdata->use_leds)
> -		twl_gpiochip.ngpio += 2;
> +		priv->gpio_chip.ngpio += 2;
>  
> -	ret = gpiochip_add(&twl_gpiochip);
> +	ret = gpiochip_add(&priv->gpio_chip);
>  	if (ret < 0) {
>  		dev_err(&pdev->dev, "could not register gpiochip, %d\n", ret);
> -		twl_gpiochip.ngpio = 0;
> +		priv->gpio_chip.ngpio = 0;
>  		gpio_twl4030_remove(pdev);
>  		goto out;
>  	}
>  
> -	twl4030_gpio_base = twl_gpiochip.base;
> +	platform_set_drvdata(pdev, priv);
>  
>  	if (pdata && pdata->setup) {
>  		int status;
>  
> -		status = pdata->setup(&pdev->dev,
> -				twl4030_gpio_base, TWL4030_GPIO_MAX);
> +		status = pdata->setup(&pdev->dev, priv->gpio_chip.base,
> +				      TWL4030_GPIO_MAX);
>  		if (status)
>  			dev_dbg(&pdev->dev, "setup --> %d\n", status);
>  	}
> @@ -510,18 +527,19 @@ out:
>  static int gpio_twl4030_remove(struct platform_device *pdev)
>  {
>  	struct twl4030_gpio_platform_data *pdata = pdev->dev.platform_data;
> +	struct gpio_twl4030_priv *priv = platform_get_drvdata(pdev);
>  	int status;
>  
>  	if (pdata && pdata->teardown) {
> -		status = pdata->teardown(&pdev->dev,
> -				twl4030_gpio_base, TWL4030_GPIO_MAX);
> +		status = pdata->teardown(&pdev->dev, priv->gpio_chip.base,
> +					 TWL4030_GPIO_MAX);
>  		if (status) {
>  			dev_dbg(&pdev->dev, "teardown --> %d\n", status);
>  			return status;
>  		}
>  	}
>  
> -	status = gpiochip_remove(&twl_gpiochip);
> +	status = gpiochip_remove(&priv->gpio_chip);
>  	if (status < 0)
>  		return status;
>  
> -- 
> 1.8.0
> 

-- 
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies, Ltd.
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