linux-kernel - [PATCH v1 4/5] pinctrl: intel: Implement high impedance support

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Message-ID: <20240828184018.3097386-5-andriy.shevchenko@linux.intel.com>
Date: Wed, 28 Aug 2024 21:38:37 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	linux-gpio@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Mika Westerberg <mika.westerberg@...ux.intel.com>,
	Andy Shevchenko <andy@...nel.org>,
	Linus Walleij <linus.walleij@...aro.org>
Subject: [PATCH v1 4/5] pinctrl: intel: Implement high impedance support

Implement high impedance support for Intel pin control hardware.
It allows to set high impedance and check it.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
 drivers/pinctrl/intel/pinctrl-intel.c | 46 +++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/drivers/pinctrl/intel/pinctrl-intel.c b/drivers/pinctrl/intel/pinctrl-intel.c
index 3a135cfe435f..ae30969b2dee 100644
--- a/drivers/pinctrl/intel/pinctrl-intel.c
+++ b/drivers/pinctrl/intel/pinctrl-intel.c
@@ -78,6 +78,7 @@
 #define PADCFG0_GPIODIS_FULL		3
 #define PADCFG0_GPIORXDIS		BIT(9)
 #define PADCFG0_GPIOTXDIS		BIT(8)
+#define PADCFG0_GPIODIS			(BIT(9) | BIT(8))
 #define PADCFG0_GPIORXSTATE		BIT(1)
 #define PADCFG0_GPIOTXSTATE		BIT(0)
 
@@ -654,6 +655,23 @@ static int intel_config_get_pull(struct intel_pinctrl *pctrl, unsigned int pin,
 	return 0;
 }
 
+static int intel_config_get_high_impedance(struct intel_pinctrl *pctrl, unsigned int pin,
+					   enum pin_config_param param, u32 *arg)
+{
+	void __iomem *padcfg0;
+	u32 value;
+
+	padcfg0 = intel_get_padcfg(pctrl, pin, PADCFG0);
+
+	scoped_guard(raw_spinlock_irqsave, &pctrl->lock)
+		value = readl(padcfg0);
+
+	if (__intel_gpio_get_direction(value) != PAD_CONNECT_NONE)
+		return -EINVAL;
+
+	return 0;
+}
+
 static int intel_config_get_debounce(struct intel_pinctrl *pctrl, unsigned int pin,
 				     enum pin_config_param param, u32 *arg)
 {
@@ -697,6 +715,12 @@ static int intel_config_get(struct pinctrl_dev *pctldev, unsigned int pin,
 			return ret;
 		break;
 
+	case PIN_CONFIG_BIAS_HIGH_IMPEDANCE:
+		ret = intel_config_get_high_impedance(pctrl, pin, param, &arg);
+		if (ret)
+			return ret;
+		break;
+
 	case PIN_CONFIG_INPUT_DEBOUNCE:
 		ret = intel_config_get_debounce(pctrl, pin, param, &arg);
 		if (ret)
@@ -795,6 +819,22 @@ static int intel_config_set_pull(struct intel_pinctrl *pctrl, unsigned int pin,
 	return 0;
 }
 
+static int intel_gpio_set_high_impedance(struct intel_pinctrl *pctrl, unsigned int pin)
+{
+	void __iomem *padcfg0;
+	u32 value;
+
+	padcfg0 = intel_get_padcfg(pctrl, pin, PADCFG0);
+
+	guard(raw_spinlock_irqsave)(&pctrl->lock);
+
+	value = readl(padcfg0);
+	value = __intel_gpio_set_direction(value, false, false);
+	writel(value, padcfg0);
+
+	return 0;
+}
+
 static int intel_config_set_debounce(struct intel_pinctrl *pctrl,
 				     unsigned int pin, unsigned int debounce)
 {
@@ -857,6 +897,12 @@ static int intel_config_set(struct pinctrl_dev *pctldev, unsigned int pin,
 				return ret;
 			break;
 
+		case PIN_CONFIG_BIAS_HIGH_IMPEDANCE:
+			ret = intel_gpio_set_high_impedance(pctrl, pin);
+			if (ret)
+				return ret;
+			break;
+
 		case PIN_CONFIG_INPUT_DEBOUNCE:
 			ret = intel_config_set_debounce(pctrl, pin,
 				pinconf_to_config_argument(configs[i]));
-- 
2.43.0.rc1.1336.g36b5255a03ac