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

["Vishnu Reddy" <vishnu.reddy@samsung.com>]

Hi Alim, Thank you for reviewing the patch.

> -----Original Message-----
> From: Alim Akhtar [mailto:alim.akhtar@samsung.com]
> Sent: 30 May 2024 08:22
> To: 'Vishnu Reddy' <vishnu.reddy@samsung.com>; krzk@kernel.org;
> s.nawrocki@samsung.com; linus.walleij@linaro.org
> Cc: linux-arm-kernel@lists.infradead.org; linux-samsung-
> soc@vger.kernel.org; linux-gpio@vger.kernel.org; linux-
> kernel@vger.kernel.org; pankaj.dubey@samsung.com;
> ravi.patel@samsung.com
> Subject: RE: [PATCH] pinctrl: samsung: Add support for pull-up and pull-down
> 
> Hi Vishnu,
> 
> > -----Original Message-----
> > From: Vishnu Reddy <vishnu.reddy@samsung.com>
> > Sent: Wednesday, May 29, 2024 12:30 PM
> > To: krzk@kernel.org; s.nawrocki@samsung.com;
> alim.akhtar@samsung.com;
> > linus.walleij@linaro.org
> > Cc: linux-arm-kernel@lists.infradead.org;
> > linux-samsung-soc@vger.kernel.org;
> > linux-gpio@vger.kernel.org; linux-kernel@vger.kernel.org;
> > pankaj.dubey@samsung.com; ravi.patel@samsung.com
> > Subject: [PATCH] pinctrl: samsung: Add support for pull-up and
> > pull-down
> >
> > 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@samsung.com>
> > ---
> >  drivers/pinctrl/samsung/pinctrl-samsung.c | 51
> > +++++++++++++++++++++++ drivers/pinctrl/samsung/pinctrl-samsung.h |
> 7
> > ++++
> >  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));
> For the mask, you can use "type->fld_width" as that is more generic and will
> work for all SoC I didn’t get, why you are multiplying offset with 4? Is this true
> for all SoC?
Ack, Will update.
> 
> > +	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;
> > +	}
> > +
> > +	raw_spin_lock_irqsave(&bank->slock, flags);
> > +	samsung_gpio_set_pud(gc, offset, value);
> > +	raw_spin_unlock_irqrestore(&bank->slock, flags);
> > +	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
> Use consistent naming conventions as per this file, so
> PIN_PUD_PULL_UP_DOWN_DISABLE PIN_PUD_PULL_DOWN_ENABLE
> PIN_PUD_PULL_UP_ENABLE
> 
Ack, Will update.
> > +
> >  /**
> >   * enum eint_type - possible external interrupt types.
> >   * @EINT_TYPE_NONE: bank does not support external interrupts
> > --
> > 2.17.1
> 
> 
Regards,
Vishnu Reddy