[PATCH] gpio: Add Intel gpio controller support

[Tomas Marek <tomas.marek@elrest.cz>]

Signed-off-by: Tomas Marek <tomas.marek@elrest.cz>
---
 drivers/gpio/Kconfig               |   5 +
 drivers/gpio/Makefile              |   1 +
 drivers/gpio/gpio-intel.c          | 198 +++++++++++++++++++++++++++++
 include/platform_data/gpio-intel.h |  10 ++
 4 files changed, 214 insertions(+)
 create mode 100644 drivers/gpio/gpio-intel.c
 create mode 100644 include/platform_data/gpio-intel.h

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 9f27addaa2..094c9b7fd4 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -219,6 +219,11 @@ config GPIO_LATCH
 	  Say yes here to enable a driver for GPIO multiplexers based on latches
 	  connected to other GPIOs.
 
+config GPIO_INTEL
+	tristate "Intel GPIO driver"
+	help
+	  Say Y or M here to build support for the Intel GPIO driver.
+
 endmenu
 
 endif
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 628e975285..b0575ccf8c 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -30,3 +30,4 @@ obj-$(CONFIG_GPIO_SIFIVE)	+= gpio-sifive.o
 obj-$(CONFIG_GPIO_STARFIVE)	+= gpio-starfive-vic.o
 obj-$(CONFIG_GPIO_ZYNQ)		+= gpio-zynq.o
 obj-$(CONFIG_GPIO_LATCH)	+= gpio-latch.o
+obj-$(CONFIG_GPIO_INTEL)	+= gpio-intel.o
diff --git a/drivers/gpio/gpio-intel.c b/drivers/gpio/gpio-intel.c
new file mode 100644
index 0000000000..ff73169ec7
--- /dev/null
+++ b/drivers/gpio/gpio-intel.c
@@ -0,0 +1,198 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+// SPDX-FileCopyrightText: 2004 Tomas Marek, Elrest Solutions Company s.r.o.
+
+/*
+ * Based on the Linux kernel v6.8 drivers/pinctrl/intel/pinctrl-intel.c.
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <io.h>
+#include <gpio.h>
+
+#include <platform_data/gpio-intel.h>
+
+#define PADBAR				0x00c
+
+/* Offset from pad_regs */
+#define PADCFG0				0x000
+#define PADCFG0_RXEVCFG_MASK		GENMASK(26, 25)
+#define PADCFG0_RXEVCFG_LEVEL		(0 << 25)
+#define PADCFG0_RXEVCFG_EDGE		(1 << 25)
+#define PADCFG0_RXEVCFG_DISABLED	(2 << 25)
+#define PADCFG0_RXEVCFG_EDGE_BOTH	(3 << 25)
+#define PADCFG0_PREGFRXSEL		BIT(24)
+#define PADCFG0_RXINV			BIT(23)
+#define PADCFG0_GPIROUTIOXAPIC		BIT(20)
+#define PADCFG0_GPIROUTSCI		BIT(19)
+#define PADCFG0_GPIROUTSMI		BIT(18)
+#define PADCFG0_GPIROUTNMI		BIT(17)
+#define PADCFG0_PMODE_SHIFT		10
+#define PADCFG0_PMODE_MASK		GENMASK(13, 10)
+#define PADCFG0_PMODE_GPIO		0
+#define PADCFG0_GPIORXDIS		BIT(9)
+#define PADCFG0_GPIOTXDIS		BIT(8)
+#define PADCFG0_GPIORXSTATE		BIT(1)
+#define PADCFG0_GPIOTXSTATE		BIT(0)
+
+struct intel_gpio_chip {
+	struct gpio_chip chip;
+	void __iomem *community_pad_base;
+};
+
+static inline struct intel_gpio_chip *to_intel_gpio(struct gpio_chip *gc)
+{
+	return container_of(gc, struct intel_gpio_chip, chip);
+}
+
+static void __iomem *intel_gpio_padcfg0_reg(const struct intel_gpio_chip *chip,
+					    const unsigned int gpio)
+{
+	const u32 pad_cfg_offset = 16;
+
+	return chip->community_pad_base + pad_cfg_offset * gpio;
+}
+
+static u32 intel_gpio_padcfg0_value(const struct intel_gpio_chip *chip,
+				    const unsigned int gpio)
+{
+	return readl(intel_gpio_padcfg0_reg(chip, gpio));
+}
+
+static void intel_gpio_padcfg0_write(const struct intel_gpio_chip *chip,
+				     const unsigned int gpio, u32 value)
+{
+	writel(value, intel_gpio_padcfg0_reg(chip, gpio));
+}
+
+static void intel_gpio_set_value(struct gpio_chip *gc, unsigned int gpio,
+				 int value)
+{
+	struct intel_gpio_chip *chip = to_intel_gpio(gc);
+	u32 padcfg0;
+
+	padcfg0 = intel_gpio_padcfg0_value(chip, gpio);
+	if (value)
+		padcfg0 |= PADCFG0_GPIOTXSTATE;
+	else
+		padcfg0 &= ~PADCFG0_GPIOTXSTATE;
+	intel_gpio_padcfg0_write(chip, gpio, padcfg0);
+}
+
+static int intel_gpio_get_value(struct gpio_chip *gc, unsigned int gpio)
+{
+	struct intel_gpio_chip *chip = to_intel_gpio(gc);
+	u32 padcfg0;
+
+	padcfg0 = intel_gpio_padcfg0_value(chip, gpio);
+	if (!(padcfg0 & PADCFG0_GPIOTXDIS))
+		return !!(padcfg0 & PADCFG0_GPIOTXSTATE);
+
+	return !!(padcfg0 & PADCFG0_GPIORXSTATE);
+}
+
+static int intel_gpio_get_direction(struct gpio_chip *gc, unsigned int gpio)
+{
+	struct intel_gpio_chip *chip = to_intel_gpio(gc);
+	u32 padcfg0;
+
+	padcfg0 = intel_gpio_padcfg0_value(chip, gpio);
+
+	if (padcfg0 & PADCFG0_PMODE_MASK)
+		return -EINVAL;
+
+	if (padcfg0 & PADCFG0_GPIOTXDIS)
+		return GPIOF_DIR_IN;
+
+	return GPIOF_DIR_IN;
+}
+
+static int intel_gpio_direction_input(struct gpio_chip *gc, unsigned int gpio)
+{
+	struct intel_gpio_chip *chip = to_intel_gpio(gc);
+	u32 padcfg0;
+
+	padcfg0 = intel_gpio_padcfg0_value(chip, gpio);
+	padcfg0 &= ~PADCFG0_GPIORXDIS;
+	padcfg0 |= PADCFG0_GPIOTXDIS;
+	intel_gpio_padcfg0_write(chip, gpio, padcfg0);
+
+	return 0;
+}
+
+static int intel_gpio_direction_output(struct gpio_chip *gc, unsigned int gpio,
+				       int value)
+{
+	struct intel_gpio_chip *chip = to_intel_gpio(gc);
+	u32 padcfg0;
+
+	padcfg0 = intel_gpio_padcfg0_value(chip, gpio);
+	padcfg0 &= ~PADCFG0_GPIOTXDIS;
+	padcfg0 |= PADCFG0_GPIORXDIS;
+	if (value)
+		padcfg0 |= PADCFG0_GPIOTXSTATE;
+	else
+		padcfg0 &= ~PADCFG0_GPIOTXSTATE;
+	intel_gpio_padcfg0_write(chip, gpio, padcfg0);
+
+	return 0;
+}
+
+static struct gpio_ops intel_gpio_ops = {
+	.direction_input = intel_gpio_direction_input,
+	.direction_output = intel_gpio_direction_output,
+	.get_direction = intel_gpio_get_direction,
+	.get = intel_gpio_get_value,
+	.set = intel_gpio_set_value,
+};
+
+static int intel_gpio_probe(struct device *dev)
+{
+	const struct gpio_intel_platform_data *pdata;
+	struct intel_gpio_chip *intel_gpio;
+	void __iomem *community_pad_base;
+	void __iomem *community_base;
+	struct resource *iores;
+	int ret;
+
+	pdata = (struct gpio_intel_platform_data *)dev->platform_data;
+	if (!pdata) {
+		dev_err(dev, "Configuration missing!\n");
+		return -EINVAL;
+	}
+
+	iores = dev_request_mem_resource(dev, 0);
+	if (IS_ERR(iores)) {
+		dev_err(dev, "Memory resource request failed: %ld\n",
+			PTR_ERR(iores));
+		return PTR_ERR(iores);
+	}
+
+	intel_gpio = xzalloc(sizeof(*intel_gpio));
+
+	intel_gpio->chip.ops = &intel_gpio_ops;
+	intel_gpio->chip.ngpio = pdata->ngpios;
+	intel_gpio->chip.dev = dev;
+
+	community_base = IOMEM(iores->start);
+	community_pad_base = IOMEM(community_base + readl(community_base + PADBAR));
+
+	intel_gpio->community_pad_base = community_pad_base;
+
+	ret = gpiochip_add(&intel_gpio->chip);
+
+	if (ret) {
+		dev_err(dev, "Couldn't add gpiochip: %d\n", ret);
+		kfree(intel_gpio);
+		return ret;
+	}
+
+	return 0;
+}
+
+static struct driver_d intel_gpio_driver = {
+	.name = "intel-gpio",
+	.probe = intel_gpio_probe,
+};
+
+coredevice_platform_driver(intel_gpio_driver);
diff --git a/include/platform_data/gpio-intel.h b/include/platform_data/gpio-intel.h
new file mode 100644
index 0000000000..f04baadd4d
--- /dev/null
+++ b/include/platform_data/gpio-intel.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef __GPIO_INTEL_H
+#define __GPIO_INTEL_H
+
+struct gpio_intel_platform_data {
+	unsigned int	ngpios;
+};
+
+#endif /* __GPIO_INTEL_H */
-- 
2.39.2