RE: [PATCH] pinctrl: samsung: Add support for pull-up and pull-down

[Vishnu Reddy]

Hi Krzysztof, Thank you for reviewing the patch.

> -----Original Message-----
> From: Krzysztof Kozlowski [mailto:krzk@xxxxxxxxxx]
> Sent: 01 June 2024 21:41
> To: Vishnu Reddy <vishnu.reddy@xxxxxxxxxxx>;
> s.nawrocki@xxxxxxxxxxx; alim.akhtar@xxxxxxxxxxx;
> linus.walleij@xxxxxxxxxx
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-samsung-
> soc@xxxxxxxxxxxxxxx; linux-gpio@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; pankaj.dubey@xxxxxxxxxxx;
> ravi.patel@xxxxxxxxxxx
> Subject: Re: [PATCH] pinctrl: samsung: Add support for pull-up and
pull-down
> 
> On 29/05/2024 08:59, Vishnu Reddy wrote:
> > gpiolib framework has the implementation of setting up the PUD
> > configuration for GPIO pins but there is no driver support.
> >
> > Add support to handle the PUD configuration request from the userspace
> > in samsung pinctrl driver.
> >
> > Signed-off-by: Vishnu Reddy <vishnu.reddy@xxxxxxxxxxx>
> > ---
> >  drivers/pinctrl/samsung/pinctrl-samsung.c | 51
> > +++++++++++++++++++++++  drivers/pinctrl/samsung/pinctrl-samsung.h
> |
> > 7 ++++
> 
> Please work on latest mainline or next branches. This was based on some
> older tree.
Ack, Will work on 'krzk/for-next' branch.
> 
> 
> >  2 files changed, 58 insertions(+)
> >
> > diff --git a/drivers/pinctrl/samsung/pinctrl-samsung.c
> > b/drivers/pinctrl/samsung/pinctrl-samsung.c
> > index ed07e23e0912..a4b6eea5e168 100644
> > --- a/drivers/pinctrl/samsung/pinctrl-samsung.c
> > +++ b/drivers/pinctrl/samsung/pinctrl-samsung.c
> > @@ -939,6 +939,56 @@ static int samsung_pinctrl_unregister(struct
> platform_device *pdev,
> >  	return 0;
> >  }
> >
> > +/*
> > + * samsung_gpio_set_pud will enable or disable the pull-down and
> > + * pull-up for the gpio pins in the PUD register.
> > + */
> > +static void samsung_gpio_set_pud(struct gpio_chip *gc, unsigned int
> offset,
> > +				 unsigned int value)
> > +{
> > +	struct samsung_pin_bank *bank = gpiochip_get_data(gc);
> > +	const struct samsung_pin_bank_type *type = bank->type;
> > +	void __iomem *reg;
> > +	unsigned int data;
> > +
> > +	reg = bank->pctl_base + bank->pctl_offset;
> > +	data = readl(reg + type->reg_offset[PINCFG_TYPE_PUD]);
> > +	data &= ~(0xf << (offset * 4));
> > +	data |= value << (offset * 4);
> > +	writel(data, reg + type->reg_offset[PINCFG_TYPE_PUD]);
> > +}
> > +
> > +/*
> > + * samsung_gpio_set_config will identify the type of PUD config based
> > + * on the gpiolib request to enable or disable the PUD configuration.
> > + */
> > +static int samsung_gpio_set_config(struct gpio_chip *gc, unsigned int
> offset,
> > +				   unsigned long config)
> > +{
> > +	struct samsung_pin_bank *bank = gpiochip_get_data(gc);
> > +	unsigned long flags;
> > +	unsigned int value = 0;
> > +
> > +	switch (pinconf_to_config_param(config)) {
> > +	case PIN_CONFIG_BIAS_DISABLE:
> > +		value = DISABLE_PIN_PULL_UP_DOWN;
> > +		break;
> > +	case PIN_CONFIG_BIAS_PULL_DOWN:
> > +		value = ENABLE_PIN_PULL_DOWN;
> > +		break;
> > +	case PIN_CONFIG_BIAS_PULL_UP:
> > +		value = ENABLE_PIN_PULL_UP;
> > +		break;
> > +	default:
> > +		return -ENOTSUPP;
> > +	}
> > +
> 
> Missing clock.
Sorry, I didn't get your point exactly. Could you please elaborate?
> 
> > +	raw_spin_lock_irqsave(&bank->slock, flags);
> > +	samsung_gpio_set_pud(gc, offset, value);
> > +	raw_spin_unlock_irqrestore(&bank->slock, flags);
> 
> Blank line
Ack, Will update.
> 
> > +	return 0;
> > +}
> > +
> >  static const struct gpio_chip samsung_gpiolib_chip = {
> >  	.request = gpiochip_generic_request,
> >  	.free = gpiochip_generic_free,
> > @@ -948,6 +998,7 @@ static const struct gpio_chip samsung_gpiolib_chip =
> {
> >  	.direction_output = samsung_gpio_direction_output,
> >  	.to_irq = samsung_gpio_to_irq,
> >  	.add_pin_ranges = samsung_add_pin_ranges,
> > +	.set_config = samsung_gpio_set_config,
> >  	.owner = THIS_MODULE,
> >  };
> >
> > diff --git a/drivers/pinctrl/samsung/pinctrl-samsung.h
> > b/drivers/pinctrl/samsung/pinctrl-samsung.h
> > index ab791afaabf5..23b70ddcaccc 100644
> > --- a/drivers/pinctrl/samsung/pinctrl-samsung.h
> > +++ b/drivers/pinctrl/samsung/pinctrl-samsung.h
> > @@ -61,6 +61,13 @@ enum pincfg_type {
> >  #define PIN_CON_FUNC_INPUT		0x0
> >  #define PIN_CON_FUNC_OUTPUT		0x1
> >
> > +/*
> > + * Values for the pin PUD register.
> > + */
> > +#define DISABLE_PIN_PULL_UP_DOWN	0x0
> > +#define ENABLE_PIN_PULL_DOWN		0x1
> > +#define ENABLE_PIN_PULL_UP		0x3
> 
> This does not look right. The value is 0x2 for s3c and s5p.
I received exynos manuals. I'll check and I'll update.
> 
> 
> 
> Best regards,
> Krzysztof