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

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

> -----Original Message-----
> From: Vishnu Reddy [mailto:vishnu.reddy@samsung.com]
> Sent: 06 June 2024 10:42
> To: 'Krzysztof Kozlowski' <krzk@kernel.org>; 's.nawrocki@samsung.com'
> <s.nawrocki@samsung.com>; 'alim.akhtar@samsung.com'
> <alim.akhtar@samsung.com>; 'linus.walleij@linaro.org'
> <linus.walleij@linaro.org>
> Cc: 'linux-arm-kernel@lists.infradead.org' <linux-arm-
> kernel@lists.infradead.org>; 'linux-samsung-soc@vger.kernel.org' <linux-
> samsung-soc@vger.kernel.org>; 'linux-gpio@vger.kernel.org' <linux-
> gpio@vger.kernel.org>; 'linux-kernel@vger.kernel.org' <linux-
> kernel@vger.kernel.org>; 'pankaj.dubey@samsung.com'
> <pankaj.dubey@samsung.com>; 'ravi.patel@samsung.com'
> <ravi.patel@samsung.com>
> Subject: RE: [PATCH] pinctrl: samsung: Add support for pull-up and
pull-down
> 
> Hi Krzysztof, Thank you for reviewing the patch.
> 
> > -----Original Message-----
> > From: Krzysztof Kozlowski [mailto:krzk@kernel.org]
> > Sent: 01 June 2024 21:41
> > To: Vishnu Reddy <vishnu.reddy@samsung.com>;
> 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: 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@samsung.com>
> > > ---
> > >  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?
I understood what is missing clock.
Ack, Will update.
> >
> > > +	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