Re: [PATCH 1/3] gpio: sch: Consolidate similar algorithms

[Mika Westerberg]

On Wed, Sep 17, 2014 at 04:49:03PM +0800, Chang Rebecca Swee Fun wrote:
> Consolidating similar algorithms into common functions to make
> GPIO SCH simpler and manageable.
> 
> Signed-off-by: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@xxxxxxxxx>
> ---
>  drivers/gpio/gpio-sch.c |   95 ++++++++++++++++++++++++++---------------------
>  1 file changed, 53 insertions(+), 42 deletions(-)
> 
> diff --git a/drivers/gpio/gpio-sch.c b/drivers/gpio/gpio-sch.c
> index 99720c8..2189c22 100644
> --- a/drivers/gpio/gpio-sch.c
> +++ b/drivers/gpio/gpio-sch.c
> @@ -43,6 +43,8 @@ struct sch_gpio {
>  
>  #define to_sch_gpio(c)	container_of(c, struct sch_gpio, chip)
>  
> +static void sch_gpio_set(struct gpio_chip *gc, unsigned gpio_num, int val);
> +

Is it possible to move the sch_gpio_set() function here instead of
forward declaring it?

>  static unsigned sch_gpio_offset(struct sch_gpio *sch, unsigned gpio,
>  				unsigned reg)
>  {
> @@ -63,94 +65,89 @@ static unsigned sch_gpio_bit(struct sch_gpio *sch, unsigned gpio)
>  	return gpio % 8;
>  }
>  
> -static void sch_gpio_enable(struct sch_gpio *sch, unsigned gpio)
> +static void sch_gpio_enable(struct sch_gpio *sch, unsigned gpio, unsigned reg)

I don't see much value in doing this.

To me sch_gpio_enable(sch, gpio) is more intuitive than
sch_gpio_enable(sch, gpio, GEN). Why do I need to pass register to
enable function in the first place? It should know better how to enable
the GPIO, right?

Same goes for others.

>  {
>  	unsigned short offset, bit;
>  	u8 enable;
>  
>  	spin_lock(&sch->lock);
>  
> -	offset = sch_gpio_offset(sch, gpio, GEN);
> +	offset = sch_gpio_offset(sch, gpio, reg);
>  	bit = sch_gpio_bit(sch, gpio);
>  
>  	enable = inb(sch->iobase + offset);
> -	if (!(enable & (1 << bit)))
> -		outb(enable | (1 << bit), sch->iobase + offset);
> +	if (!(enable & BIT(bit)))
> +		outb(enable | BIT(bit), sch->iobase + offset);
>  
>  	spin_unlock(&sch->lock);
>  }
>  
> -static int sch_gpio_direction_in(struct gpio_chip *gc, unsigned  gpio_num)
> +static void sch_gpio_disable(struct sch_gpio *sch, unsigned gpio, unsigned reg)
>  {
> -	struct sch_gpio *sch = to_sch_gpio(gc);
> -	u8 curr_dirs;
>  	unsigned short offset, bit;
> +	u8 disable;
>  
>  	spin_lock(&sch->lock);
>  
> -	offset = sch_gpio_offset(sch, gpio_num, GIO);
> -	bit = sch_gpio_bit(sch, gpio_num);
> -
> -	curr_dirs = inb(sch->iobase + offset);
> +	offset = sch_gpio_offset(sch, gpio, reg);
> +	bit = sch_gpio_bit(sch, gpio);
>  
> -	if (!(curr_dirs & (1 << bit)))
> -		outb(curr_dirs | (1 << bit), sch->iobase + offset);
> +	disable = inb(sch->iobase + offset);
> +	if (disable & BIT(bit))
> +		outb(disable & ~BIT(bit), sch->iobase + offset);
>  
>  	spin_unlock(&sch->lock);
> -	return 0;
>  }
>  
> -static int sch_gpio_get(struct gpio_chip *gc, unsigned gpio_num)
> +static int sch_gpio_reg_get(struct gpio_chip *gc, unsigned gpio, unsigned reg)
>  {
>  	struct sch_gpio *sch = to_sch_gpio(gc);
> -	int res;
>  	unsigned short offset, bit;
> +	u8 curr_dirs;
>  
> -	offset = sch_gpio_offset(sch, gpio_num, GLV);
> -	bit = sch_gpio_bit(sch, gpio_num);
> +	offset = sch_gpio_offset(sch, gpio, reg);
> +	bit = sch_gpio_bit(sch, gpio);
>  
> -	res = !!(inb(sch->iobase + offset) & (1 << bit));
> +	curr_dirs = !!(inb(sch->iobase + offset) & BIT(bit));
>  
> -	return res;
> +	return curr_dirs;
>  }
>  
> -static void sch_gpio_set(struct gpio_chip *gc, unsigned gpio_num, int val)
> +static void sch_gpio_reg_set(struct gpio_chip *gc, unsigned gpio, unsigned reg,
> +			     int val)
>  {
>  	struct sch_gpio *sch = to_sch_gpio(gc);
> -	u8 curr_vals;
>  	unsigned short offset, bit;
> +	u8 curr_dirs;
>  
> -	spin_lock(&sch->lock);
> -
> -	offset = sch_gpio_offset(sch, gpio_num, GLV);
> -	bit = sch_gpio_bit(sch, gpio_num);
> +	offset = sch_gpio_offset(sch, gpio, reg);
> +	bit = sch_gpio_bit(sch, gpio);
>  
> -	curr_vals = inb(sch->iobase + offset);
> +	curr_dirs = inb(sch->iobase + offset);
>  
>  	if (val)
> -		outb(curr_vals | (1 << bit), sch->iobase + offset);
> +		outb(curr_dirs | BIT(bit), sch->iobase + offset);
>  	else
> -		outb((curr_vals & ~(1 << bit)), sch->iobase + offset);
> +		outb((curr_dirs & ~BIT(bit)), sch->iobase + offset);
> +}
> +
> +static int sch_gpio_direction_in(struct gpio_chip *gc, unsigned gpio_num)
> +{
> +	struct sch_gpio *sch = to_sch_gpio(gc);
>  
> +	spin_lock(&sch->lock);
> +	sch_gpio_enable(sch, gpio_num, GIO);
>  	spin_unlock(&sch->lock);
> +	return 0;
>  }
>  
>  static int sch_gpio_direction_out(struct gpio_chip *gc, unsigned gpio_num,
>  				  int val)
>  {
>  	struct sch_gpio *sch = to_sch_gpio(gc);
> -	u8 curr_dirs;
> -	unsigned short offset, bit;
>  
>  	spin_lock(&sch->lock);
> -
> -	offset = sch_gpio_offset(sch, gpio_num, GIO);
> -	bit = sch_gpio_bit(sch, gpio_num);
> -
> -	curr_dirs = inb(sch->iobase + offset);
> -	if (curr_dirs & (1 << bit))
> -		outb(curr_dirs & ~(1 << bit), sch->iobase + offset);
> -
> +	sch_gpio_disable(sch, gpio_num, GIO);
>  	spin_unlock(&sch->lock);
>  
>  	/*
> @@ -166,6 +163,20 @@ static int sch_gpio_direction_out(struct gpio_chip *gc, unsigned gpio_num,
>  	return 0;
>  }
>  
> +static int sch_gpio_get(struct gpio_chip *gc, unsigned gpio_num)
> +{
> +	return sch_gpio_reg_get(gc, gpio_num, GLV);
> +}
> +
> +static void sch_gpio_set(struct gpio_chip *gc, unsigned gpio_num, int val)
> +{
> +	struct sch_gpio *sch = to_sch_gpio(gc);
> +
> +	spin_lock(&sch->lock);
> +	sch_gpio_reg_set(gc, gpio_num, GLV, val);
> +	spin_unlock(&sch->lock);
> +}
> +
>  static struct gpio_chip sch_gpio_chip = {
>  	.label			= "sch_gpio",
>  	.owner			= THIS_MODULE,
> @@ -209,13 +220,13 @@ static int sch_gpio_probe(struct platform_device *pdev)
>  		 * GPIO7 is configured by the CMC as SLPIOVR
>  		 * Enable GPIO[9:8] core powered gpios explicitly
>  		 */
> -		sch_gpio_enable(sch, 8);
> -		sch_gpio_enable(sch, 9);
> +		sch_gpio_enable(sch, 8, GEN);
> +		sch_gpio_enable(sch, 9, GEN);

For example here, which one is more readable?

>  		/*
>  		 * SUS_GPIO[2:0] enabled by default
>  		 * Enable SUS_GPIO3 resume powered gpio explicitly
>  		 */
> -		sch_gpio_enable(sch, 13);
> +		sch_gpio_enable(sch, 13, GEN);

Or here?

>  		break;
>  
>  	case PCI_DEVICE_ID_INTEL_ITC_LPC:
> -- 
> 1.7.9.5
> 
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