Re: [RFC PATCH alt 4/4] pinctrl: at91: rework debounce configuration

[Jean-Christophe PLAGNIOL-VILLARD]

On 09:53 Fri 13 Sep     , Boris BREZILLON wrote:
> AT91 SoCs do not support per pin debounce time configuration.
> Instead you have to configure a debounce time which will be used for all
> pins of a given bank (PIOA, PIOB, ...).
> 
> Signed-off-by: Boris BREZILLON <b.brezillon@xxxxxxxxxxx>
> ---
>  .../bindings/pinctrl/atmel,at91-pinctrl.txt        |    9 ++-
>  drivers/pinctrl/pinctrl-at91.c                     |   79 ++++++++++++++++----
>  include/dt-bindings/pinctrl/at91.h                 |    1 -
>  3 files changed, 73 insertions(+), 16 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/pinctrl/atmel,at91-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/atmel,at91-pinctrl.txt
> index cf7c7bc..8a4cdeb 100644
> --- a/Documentation/devicetree/bindings/pinctrl/atmel,at91-pinctrl.txt
> +++ b/Documentation/devicetree/bindings/pinctrl/atmel,at91-pinctrl.txt
> @@ -78,6 +78,14 @@ PA31	TXD4
>  
>  => 0xffc00c3b
>  
> +Optional properties for iomux controller:
> +- atmel,default-debounce-div: array of debounce divisors (one divisor per bank)
> +  which describes the debounce timing in use for all pins of a given bank
> +  configured with the DEBOUNCE option (see the following description).
> +  Debounce timing is obtained with this formula:
> +  Tdebounce = 2 * (debouncediv + 1) / Fslowclk
> +  with Fslowclk = 32KHz

I known that I put the div in the original binding

but maybe we should just put the debounce timing in the DT and calculate the
div in C
> +
>  Required properties for pin configuration node:
>  - atmel,pins: 4 integers array, represents a group of pins mux and config
>    setting. The format is atmel,pins = <PIN_BANK PIN_BANK_NUM PERIPH CONFIG>.
> @@ -91,7 +99,6 @@ DEGLITCH	(1 << 2): indicate this pin need deglitch.
>  PULL_DOWN	(1 << 3): indicate this pin need a pull down.
>  DIS_SCHMIT	(1 << 4): indicate this pin need to disable schmit trigger.
>  DEBOUNCE	(1 << 16): indicate this pin need debounce.
> -DEBOUNCE_VAL	(0x3fff << 17): debounce val.
>  
>  NOTE:
>  Some requirements for using atmel,at91rm9200-pinctrl binding:
> diff --git a/drivers/pinctrl/pinctrl-at91.c b/drivers/pinctrl/pinctrl-at91.c
> index ac9dbea..2903758 100644
> --- a/drivers/pinctrl/pinctrl-at91.c
> +++ b/drivers/pinctrl/pinctrl-at91.c
> @@ -62,8 +62,6 @@ static int gpio_banks;
>  #define PULL_DOWN	(1 << 3)
>  #define DIS_SCHMIT	(1 << 4)
>  #define DEBOUNCE	(1 << 16)
> -#define DEBOUNCE_VAL_SHIFT	17
> -#define DEBOUNCE_VAL	(0x3fff << DEBOUNCE_VAL_SHIFT)
>  
>  /**
>   * struct at91_pmx_func - describes AT91 pinmux functions
> @@ -145,8 +143,10 @@ struct at91_pinctrl_mux_ops {
>  	void (*mux_D_periph)(void __iomem *pio, unsigned mask);
>  	bool (*get_deglitch)(void __iomem *pio, unsigned pin);
>  	void (*set_deglitch)(void __iomem *pio, unsigned mask, bool is_on);
> -	bool (*get_debounce)(void __iomem *pio, unsigned pin, u32 *div);
> -	void (*set_debounce)(void __iomem *pio, unsigned mask, bool is_on, u32 div);
> +	bool (*get_debounce)(void __iomem *pio, unsigned pin);
> +	void (*set_debounce)(void __iomem *pio, unsigned mask, bool is_on);
> +	u32 (*get_debounce_div)(void __iomem *pio);
> +	void (*set_debounce_div)(void __iomem *pio, u32 div);
why do you split it?

if it's just get if on or not put NULL to div but do not add more function
pointer
>  	bool (*get_pulldown)(void __iomem *pio, unsigned pin);
>  	void (*set_pulldown)(void __iomem *pio, unsigned mask, bool is_on);
>  	bool (*get_schmitt_trig)(void __iomem *pio, unsigned pin);
> @@ -432,25 +432,32 @@ static void at91_mux_pio3_set_deglitch(void __iomem *pio, unsigned mask, bool is
>  	at91_mux_set_deglitch(pio, mask, is_on);
>  }
>  
> -static bool at91_mux_pio3_get_debounce(void __iomem *pio, unsigned pin, u32 *div)
> +static bool at91_mux_pio3_get_debounce(void __iomem *pio, unsigned pin)
>  {
> -	*div = __raw_readl(pio + PIO_SCDR);
> -
>  	return ((__raw_readl(pio + PIO_IFSR) >> pin) & 0x1) &&
>  	       ((__raw_readl(pio + PIO_IFSCSR) >> pin) & 0x1);
>  }
>  
>  static void at91_mux_pio3_set_debounce(void __iomem *pio, unsigned mask,
> -				bool is_on, u32 div)
> +				bool is_on)
>  {
>  	if (is_on) {
>  		__raw_writel(mask, pio + PIO_IFSCER);
> -		__raw_writel(div & PIO_SCDR_DIV, pio + PIO_SCDR);
>  		__raw_writel(mask, pio + PIO_IFER);
>  	} else
>  		__raw_writel(mask, pio + PIO_IFSCDR);
>  }
>  
> +static u32 at91_mux_pio3_get_debounce_div(void __iomem *pio)
> +{
> +	return __raw_readl(pio + PIO_SCDR) & PIO_SCDR_DIV;
> +}
> +
> +static void at91_mux_pio3_set_debounce_div(void __iomem *pio, u32 div)
> +{
> +	__raw_writel(div & PIO_SCDR_DIV, pio + PIO_SCDR);
> +}
> +
>  static bool at91_mux_pio3_get_pulldown(void __iomem *pio, unsigned pin)
>  {
>  	return !((__raw_readl(pio + PIO_PPDSR) >> pin) & 0x1);
> @@ -490,6 +497,8 @@ static struct at91_pinctrl_mux_ops at91sam9x5_ops = {
>  	.set_deglitch	= at91_mux_pio3_set_deglitch,
>  	.get_debounce	= at91_mux_pio3_get_debounce,
>  	.set_debounce	= at91_mux_pio3_set_debounce,
> +	.get_debounce_div = at91_mux_pio3_get_debounce_div,
> +	.set_debounce_div = at91_mux_pio3_set_debounce_div,
>  	.get_pulldown	= at91_mux_pio3_get_pulldown,
>  	.set_pulldown	= at91_mux_pio3_set_pulldown,
>  	.get_schmitt_trig = at91_mux_pio3_get_schmitt_trig,
> @@ -719,7 +728,6 @@ static int at91_pinconf_get(struct pinctrl_dev *pctldev,
>  	struct at91_pinctrl *info = pinctrl_dev_get_drvdata(pctldev);
>  	void __iomem *pio;
>  	unsigned pin;
> -	int div;
>  
>  	dev_dbg(info->dev, "%s:%d, pin_id=%d, config=0x%lx", __func__, __LINE__, pin_id, *config);
>  	pio = pin_to_controller(info, pin_to_bank(pin_id));
> @@ -734,8 +742,8 @@ static int at91_pinconf_get(struct pinctrl_dev *pctldev,
>  
>  	if (info->ops->get_deglitch && info->ops->get_deglitch(pio, pin))
>  		*config |= DEGLITCH;
> -	if (info->ops->get_debounce && info->ops->get_debounce(pio, pin, &div))
> -		*config |= DEBOUNCE | (div << DEBOUNCE_VAL_SHIFT);
> +	if (info->ops->get_debounce && info->ops->get_debounce(pio, pin))
> +		*config |= DEBOUNCE;
>  	if (info->ops->get_pulldown && info->ops->get_pulldown(pio, pin))
>  		*config |= PULL_DOWN;
>  	if (info->ops->get_schmitt_trig && info->ops->get_schmitt_trig(pio, pin))
> @@ -765,8 +773,7 @@ static int at91_pinconf_set(struct pinctrl_dev *pctldev,
>  		if (!info->ops->set_debounce)
>  			return -ENOTSUPP;
>  
> -		info->ops->set_debounce(pio, mask, config & DEBOUNCE,
> -				(config & DEBOUNCE_VAL) >> DEBOUNCE_VAL_SHIFT);
> +		info->ops->set_debounce(pio, mask, config & DEBOUNCE);
>  	} else if (info->ops->set_deglitch)
>  		info->ops->set_deglitch(pio, mask, config & DEGLITCH);
>  
> @@ -822,6 +829,39 @@ static void at91_pinctrl_child_count(struct at91_pinctrl *info,
>  	}
>  }
>  
> +static int at91_pinctrl_default_debounce_div(struct at91_pinctrl *info,
> +					     struct device_node *np)
> +{
> +	int size;
> +	int i;
> +	int ret;
> +
> +	if (!info->ops->set_debounce_div ||
> +	    !of_get_property(np, "atmel,default-debounce-div", &size))
> +		return 0;
> +
> +	size /= sizeof(u32);
> +	if (size != info->nbanks) {
> +		dev_err(info->dev,
> +			"atmel,default-debounce-div property should contain %d elements\n",
> +			info->nbanks);
> +		return -EINVAL;
> +	}
> +
> +	for (i = 0; i < info->nbanks; i++) {
> +		u32 val;
> +		ret = of_property_read_u32_index(np,
> +						 "atmel,default-debounce-div",
> +						 i, &val);
> +		if (ret)
> +			return ret;
> +
> +		info->ops->set_debounce_div(gpio_chips[i]->regbase, val);
> +	}
> +
> +	return 0;
> +}
> +
>  static int at91_pinctrl_mux_mask(struct at91_pinctrl *info,
>  				 struct device_node *np)
>  {
> @@ -972,6 +1012,10 @@ static int at91_pinctrl_probe_dt(struct platform_device *pdev,
>  	if (ret)
>  		return ret;
>  
> +	ret = at91_pinctrl_default_debounce_div(info, np);
> +	if (ret)
> +		return ret;
> +
>  	dev_dbg(&pdev->dev, "nmux = %d\n", info->nmux);
>  
>  	dev_dbg(&pdev->dev, "mux-mask\n");
> @@ -982,6 +1026,13 @@ static int at91_pinctrl_probe_dt(struct platform_device *pdev,
>  		}
>  	}
>  
> +	if (info->ops->get_debounce_div) {
> +		dev_dbg(&pdev->dev, "default-debounce-div\n");
> +		for (i = 0; i < info->nbanks; i++)
> +			dev_dbg(&pdev->dev, "bank %d\t%d\n", i,
> +				info->ops->get_debounce_div(gpio_chips[i]->regbase));
> +	}
> +
>  	dev_dbg(&pdev->dev, "nfunctions = %d\n", info->nfunctions);
>  	dev_dbg(&pdev->dev, "ngroups = %d\n", info->ngroups);
>  	info->functions = devm_kzalloc(&pdev->dev, info->nfunctions * sizeof(struct at91_pmx_func),
> diff --git a/include/dt-bindings/pinctrl/at91.h b/include/dt-bindings/pinctrl/at91.h
> index 0fee6ff..b478954 100644
> --- a/include/dt-bindings/pinctrl/at91.h
> +++ b/include/dt-bindings/pinctrl/at91.h
> @@ -16,7 +16,6 @@
>  #define AT91_PINCTRL_PULL_DOWN		(1 << 3)
>  #define AT91_PINCTRL_DIS_SCHMIT		(1 << 4)
>  #define AT91_PINCTRL_DEBOUNCE		(1 << 16)
> -#define AT91_PINCTRL_DEBOUNCE_VAL(x)	(x << 17)
>  
>  #define AT91_PINCTRL_PULL_UP_DEGLITCH	(AT91_PINCTRL_PULL_UP | AT91_PINCTRL_DEGLITCH)
>  
> -- 
> 1.7.9.5
> 
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