RE: [PATCH v3] pinctrl: samsung: Add support for pull-up and pull-down

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

> -----Original Message-----
> From: Krzysztof Kozlowski [mailto:krzysztof.kozlowski@linaro.org]
> Sent: 05 July 2024 15:09
> 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; gost.dev@samsung.com
> Subject: Re: [PATCH v3] pinctrl: samsung: Add support for pull-up and pull-
> down
> 
> On 04/07/2024 06:26, 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-exynos-arm.c | 15 ++++
> >  drivers/pinctrl/samsung/pinctrl-s3c64xx.c    | 15 ++++
> >  drivers/pinctrl/samsung/pinctrl-samsung.c    | 80
> ++++++++++++++++++++
> >  drivers/pinctrl/samsung/pinctrl-samsung.h    | 24 ++++++
> >  4 files changed, 134 insertions(+)
> >
> > diff --git a/drivers/pinctrl/samsung/pinctrl-exynos-arm.c
> > b/drivers/pinctrl/samsung/pinctrl-exynos-arm.c
> > index 85ddf49a5188..426d1daacef2 100644
> > --- a/drivers/pinctrl/samsung/pinctrl-exynos-arm.c
> > +++ b/drivers/pinctrl/samsung/pinctrl-exynos-arm.c
> > @@ -40,6 +40,20 @@ static const struct samsung_pin_bank_type
> bank_type_alive = {
> >  #define S5P_OTHERS_RET_MMC		(1 << 29)
> >  #define S5P_OTHERS_RET_UART		(1 << 28)
> >
> > +/*
> > + * s5pv210_pud_value_init: initialize the drvdata pud_val with s5pv210
> pud values
> > + * s5pv210_pull_disable:	0
> > + * s5pv210_pull_down_enable:	1
> > + * s5pv210_pull_up_enable:	2
> 
> Please use proper defines, e.g. S5P_PIN_PUD_PULL_DISABLE
Ack, Will update.
> 
> 
> > + */
> > +static void s5pv210_pud_value_init(struct samsung_pinctrl_drv_data
> > +*drvdata) {
> > +	unsigned int i, *pud_val = drvdata->pud_val;
> > +
> > +	for (i = 0; i < PUD_MAX; i++)
> > +		pud_val[i] = i;
> 
> pud_val[PUD_PULL_DISABLE] = PROPER_DEFINE
> 
> > +}
> > +
> >  static void s5pv210_retention_disable(struct samsung_pinctrl_drv_data
> > *drvdata)  {
> >  	void __iomem *clk_base = (void __iomem
> > *)drvdata->retention_ctrl->priv; @@ -133,6 +147,7 @@ static const struct
> samsung_pin_ctrl s5pv210_pin_ctrl[] __initconst = {
> >  		.nr_banks	= ARRAY_SIZE(s5pv210_pin_bank),
> >  		.eint_gpio_init = exynos_eint_gpio_init,
> >  		.eint_wkup_init = exynos_eint_wkup_init,
> > +		.pud_value_init	= s5pv210_pud_value_init,
> >  		.suspend	= exynos_pinctrl_suspend,
> >  		.resume		= exynos_pinctrl_resume,
> >  		.retention_data	= &s5pv210_retention_data,
> > diff --git a/drivers/pinctrl/samsung/pinctrl-s3c64xx.c
> > b/drivers/pinctrl/samsung/pinctrl-s3c64xx.c
> > index c5d92db4fdb1..cf57b0f16999 100644
> > --- a/drivers/pinctrl/samsung/pinctrl-s3c64xx.c
> > +++ b/drivers/pinctrl/samsung/pinctrl-s3c64xx.c
> > @@ -255,6 +255,20 @@ static int s3c64xx_irq_get_trigger(unsigned int
> type)
> >  	return trigger;
> >  }
> >
> > +/*
> > + * s3c64xx_pud_value_init: initialize the drvdata pud_val with s3c64xx pud
> values
> > + * s3c64xx_pull_disable:	0
> > + * s3c64xx_pull_down_enable:	1
> > + * s3c64xx_pull_up_enable:	2
> 
> Use proper defines. Comments are not the place to define magic values.
Ack, Will update.
> 
> 
> > + */
> > +static void s3c64xx_pud_value_init(struct samsung_pinctrl_drv_data
> > +*drvdata) {
> > +	unsigned int i, *pud_val = drvdata->pud_val;
> > +
> > +	for (i = 0; i < PUD_MAX; i++)
> > +		pud_val[i] = i;
> > +}
> > +
> >  static void s3c64xx_irq_set_handler(struct irq_data *d, unsigned int
> > type)  {
> >  	/* Edge- and level-triggered interrupts need different handlers */
> > @@ -797,6 +811,7 @@ static const struct samsung_pin_ctrl
> s3c64xx_pin_ctrl[] __initconst = {
> >  		.nr_banks	= ARRAY_SIZE(s3c64xx_pin_banks0),
> >  		.eint_gpio_init = s3c64xx_eint_gpio_init,
> >  		.eint_wkup_init = s3c64xx_eint_eint0_init,
> > +		.pud_value_init	= s3c64xx_pud_value_init,
> >  	},
> >  };
> >
> > diff --git a/drivers/pinctrl/samsung/pinctrl-samsung.c
> > b/drivers/pinctrl/samsung/pinctrl-samsung.c
> > index 623df65a5d6f..7d7e924c1fdb 100644
> > --- a/drivers/pinctrl/samsung/pinctrl-samsung.c
> > +++ b/drivers/pinctrl/samsung/pinctrl-samsung.c
> > @@ -997,6 +997,80 @@ static int samsung_pinctrl_unregister(struct
> platform_device *pdev,
> >  	return 0;
> >  }
> >
> > +/*
> > + *samsung_pud_value_init: initialize the drvdata pud_val
> 
> You use some weird style of comments. It's not kerneldoc, it's not a proper
> neither useful comment. Either use proper kerneldoc (and test
> it!) or drop duplicated function names. They are not helping. This applies
> everywhere.
Ack, Will update.
> 
> 
> > + */
> > +static void samsung_pud_value_init(struct samsung_pinctrl_drv_data
> > +*drvdata) {
> > +	unsigned int  *pud_val = drvdata->pud_val;
> > +
> > +	pud_val[PUD_PULL_DISABLE] =
> PIN_PUD_PULL_UP_DOWN_DISABLE;
> > +	pud_val[PUD_PULL_DOWN] = PIN_PUD_PULL_DOWN_ENABLE;
> > +	pud_val[PUD_PULL_UP] = PIN_PUD_PULL_UP_ENABLE; }
> > +
> > +/*
> > + * 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, mask;
> > +
> > +	reg = bank->pctl_base + bank->pctl_offset;
> > +	data = readl(reg + type->reg_offset[PINCFG_TYPE_PUD]);
> > +	mask = (1 << type->fld_width[PINCFG_TYPE_PUD]) - 1;
> > +	data &= ~(mask << (offset * type->fld_width[PINCFG_TYPE_PUD]));
> > +	data |= value << (offset * type->fld_width[PINCFG_TYPE_PUD]);
> > +	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);
> > +	struct samsung_pinctrl_drv_data *drvdata = bank->drvdata;
> > +	unsigned int value;
> > +	int ret = 0;
> > +	unsigned long flags;
> > +
> > +	switch (pinconf_to_config_param(config)) {
> > +	case PIN_CONFIG_BIAS_DISABLE:
> > +		value = drvdata->pud_val[PUD_PULL_DISABLE];
> > +		break;
> > +	case PIN_CONFIG_BIAS_PULL_DOWN:
> > +		value = drvdata->pud_val[PUD_PULL_DOWN];
> > +		break;
> > +	case PIN_CONFIG_BIAS_PULL_UP:
> > +		value = drvdata->pud_val[PUD_PULL_UP];
> > +		break;
> > +	default:
> > +		return -ENOTSUPP;
> > +	}
> > +
> > +	ret = clk_enable(drvdata->pclk);
> > +	if (ret) {
> > +		dev_err(drvdata->dev, "failed to enable clock\n");
> > +		return ret;
> > +	}
> > +
> > +	raw_spin_lock_irqsave(&bank->slock, flags);
> > +	samsung_gpio_set_pud(gc, offset, value);
> > +	raw_spin_unlock_irqrestore(&bank->slock, flags);
> > +
> > +	clk_disable(drvdata->pclk);
> > +
> > +	return ret;
> > +}
> > +
> >  static const struct gpio_chip samsung_gpiolib_chip = {
> >  	.request = gpiochip_generic_request,
> >  	.free = gpiochip_generic_free,
> > @@ -1006,6 +1080,7 @@ 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,
> >  };
> >
> > @@ -1237,6 +1312,11 @@ static int samsung_pinctrl_probe(struct
> platform_device *pdev)
> >  	if (ctrl->eint_wkup_init)
> >  		ctrl->eint_wkup_init(drvdata);
> >
> > +	if (ctrl->pud_value_init)
> > +		ctrl->pud_value_init(drvdata);
> > +	else
> > +		samsung_pud_value_init(drvdata);
> > +
> >  	ret = samsung_gpiolib_register(pdev, drvdata);
> >  	if (ret)
> >  		goto err_unregister;
> > diff --git a/drivers/pinctrl/samsung/pinctrl-samsung.h
> > b/drivers/pinctrl/samsung/pinctrl-samsung.h
> > index d50ba6f07d5d..61384096b6d7 100644
> > --- a/drivers/pinctrl/samsung/pinctrl-samsung.h
> > +++ b/drivers/pinctrl/samsung/pinctrl-samsung.h
> > @@ -61,6 +61,28 @@ enum pincfg_type {
> >  #define PIN_CON_FUNC_INPUT		0x0
> >  #define PIN_CON_FUNC_OUTPUT		0x1
> >
> > +/*
> > + * Values for the pin PUD register.
> > + */
> > +#define PIN_PUD_PULL_UP_DOWN_DISABLE	0x0
> 
> EXYNOS_PIN_PUD_PULL_DISABLE
> 
> > +#define PIN_PUD_PULL_DOWN_ENABLE	0x1
> 
> EXYNOS_PIN_PID_PULL_DOWN
> 
> > +#define PIN_PUD_PULL_UP_ENABLE		0x3
> 
> EXYNOS_PIN_PID_PULL_UP
Ack, Will update.
> 
> > +
> > +/*
> > + * enum pud_index: Index values to access the pud_val array in
> > + *	struct samsung_pinctrl_drv_data.
> > + * @PUD_PULL_DISABLE: Index for value of pud disable
> > + * @PUD_PULL_DOWN: Index for the value of pull down enable
> > + * @PUD_PULL_UP: Index for the value of pull up enable
> > + * @PUD_MAX: Maximun value of the index
> 
> Typo: Maximum
Ack, Will update.
> 
> > + */
> > +enum pud_index {
> > +	PUD_PULL_DISABLE,
> > +	PUD_PULL_DOWN,
> > +	PUD_PULL_UP,
> > +	PUD_MAX,
> > +};
> 
> Best regards,
> Krzysztof