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

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Message-Id: <20240529065939.36369-1-vishnu.reddy@samsung.com>
Date: Wed, 29 May 2024 12:29:39 +0530
From: Vishnu Reddy <vishnu.reddy@...sung.com>
To: krzk@...nel.org, s.nawrocki@...sung.com, alim.akhtar@...sung.com,
	linus.walleij@...aro.org
Cc: linux-arm-kernel@...ts.infradead.org, linux-samsung-soc@...r.kernel.org,
	linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
	pankaj.dubey@...sung.com, ravi.patel@...sung.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@...sung.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));
+	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
+
 /**
  * enum eint_type - possible external interrupt types.
  * @EINT_TYPE_NONE: bank does not support external interrupts
-- 
2.17.1