[PATCH v3 03/12] gpio: Add GPIO driver for Intel EG20T

[Uros Stajic]

From: Chao-ying Fu <cfu at mips.com>

Add a GPIO driver for the Intel EG20T Platform Controller Hub, which
exposes a set of 12 GPIOs via PCI MMIO.

The driver implements basic GPIO operations (input/output direction,
value read/write, and function query) using the U-Boot driver model
infrastructure. It maps the required BAR1 region via `dm_pci_map_bar`
and uses internal registers to control pin state and direction.

This driver is required for platforms using EG20T, such as P8700-based
systems, to access GPIOs through the standard U-Boot DM GPIO framework.

Signed-off-by: Chao-ying Fu <cfu at mips.com>
Signed-off-by: Uros Stajic <uros.stajic at htecgroup.com>
---
 board/mips/boston-riscv/MAINTAINERS |   1 +
 drivers/gpio/Kconfig                |   7 ++
 drivers/gpio/Makefile               |   1 +
 drivers/gpio/eg20t-gpio.c           | 138 ++++++++++++++++++++++++++++
 4 files changed, 147 insertions(+)
 create mode 100644 drivers/gpio/eg20t-gpio.c

diff --git a/board/mips/boston-riscv/MAINTAINERS b/board/mips/boston-riscv/MAINTAINERS
index e350121395e..bc59a628c79 100644
--- a/board/mips/boston-riscv/MAINTAINERS
+++ b/board/mips/boston-riscv/MAINTAINERS
@@ -7,3 +7,4 @@ F:  arch/riscv/cpu/p8700/
 F:  arch/riscv/include/asm/arch-p8700/
 F:  configs/boston-p8700_defconfig
 F:  arch/riscv/dts/boston-p8700.dts
+F:  drivers/gpio/eg20t-gpio.c
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 58e464106a3..26040947a69 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -726,3 +726,10 @@ config MPFS_GPIO
 		Enable to support the GPIO driver on Polarfire SoC
 
 endif
+
+config EG20T_GPIO
+        bool "Intel EG20T GPIO driver"
+        depends on DM_GPIO && DM_PCI
+        help
+          Enable this to support the GPIO controller found in the Intel EG20T
+          Platform Controller Hub.
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 83e10c79b91..e44122cb9aa 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -81,3 +81,4 @@ obj-$(CONFIG_FTGPIO010)		+= ftgpio010.o
 obj-$(CONFIG_$(PHASE_)ADP5585_GPIO)	+= adp5585_gpio.o
 obj-$(CONFIG_RZG2L_GPIO)	+= rzg2l-gpio.o
 obj-$(CONFIG_MPFS_GPIO)	+= mpfs_gpio.o
+obj-$(CONFIG_EG20T_GPIO)	+= eg20t-gpio.o
diff --git a/drivers/gpio/eg20t-gpio.c b/drivers/gpio/eg20t-gpio.c
new file mode 100644
index 00000000000..d41ca4bfb17
--- /dev/null
+++ b/drivers/gpio/eg20t-gpio.c
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2016 Imagination Technologies
+ */
+
+#include <dm.h>
+#include <errno.h>
+#include <pci.h>
+#include <asm/io.h>
+#include <asm/gpio.h>
+#include <log.h>
+
+enum {
+	REG_IEN		= 0x00,
+	REG_ISTATUS	= 0x04,
+	REG_IDISP	= 0x08,
+	REG_ICLR	= 0x0c,
+	REG_IMASK	= 0x10,
+	REG_IMASKCLR	= 0x14,
+	REG_PO		= 0x18,
+	REG_PI		= 0x1c,
+	REG_PM		= 0x20,
+};
+
+struct eg20t_gpio_priv {
+	void *base;
+};
+
+static int eg20t_gpio_get_value(struct udevice *dev, unsigned int offset)
+{
+	struct eg20t_gpio_priv *priv = dev_get_priv(dev);
+	u32 pm, pval;
+
+	pm = readl(priv->base + REG_PM);
+	if ((pm >> offset) & 0x1)
+		pval = readl(priv->base + REG_PO);
+	else
+		pval = readl(priv->base + REG_PI);
+
+	return (pval >> offset) & 0x1;
+}
+
+static int eg20t_gpio_set_value(struct udevice *dev, unsigned int offset,
+				int value)
+{
+	struct eg20t_gpio_priv *priv = dev_get_priv(dev);
+	u32 po;
+
+	po = readl(priv->base + REG_PO);
+	if (value)
+		po |= 1 << offset;
+	else
+		po &= ~(1 << offset);
+	writel(po, priv->base + REG_PO);
+	return 0;
+}
+
+static int eg20t_gpio_direction_input(struct udevice *dev, unsigned int offset)
+{
+	struct eg20t_gpio_priv *priv = dev_get_priv(dev);
+	u32 pm;
+
+	pm = readl(priv->base + REG_PM);
+	pm &= ~(1 << offset);
+	writel(pm, priv->base + REG_PM);
+	return 0;
+}
+
+static int eg20t_gpio_direction_output(struct udevice *dev, unsigned int offset,
+				       int value)
+{
+	struct eg20t_gpio_priv *priv = dev_get_priv(dev);
+	u32 pm;
+
+	pm = readl(priv->base + REG_PM);
+	pm |= 1 << offset;
+	writel(pm, priv->base + REG_PM);
+
+	return eg20t_gpio_set_value(dev, offset, value);
+}
+
+static int eg20t_gpio_get_function(struct udevice *dev, unsigned int offset)
+{
+	struct eg20t_gpio_priv *priv = dev_get_priv(dev);
+	u32 pm;
+
+	pm = readl(priv->base + REG_PM);
+
+	if ((pm >> offset) & 0x1)
+		return GPIOF_OUTPUT;
+
+	return GPIOF_INPUT;
+}
+
+static const struct dm_gpio_ops eg20t_gpio_ops = {
+	.direction_input	= eg20t_gpio_direction_input,
+	.direction_output	= eg20t_gpio_direction_output,
+	.get_value		= eg20t_gpio_get_value,
+	.set_value		= eg20t_gpio_set_value,
+	.get_function		= eg20t_gpio_get_function,
+};
+
+static int eg20t_gpio_probe(struct udevice *dev)
+{
+	struct eg20t_gpio_priv *priv = dev_get_priv(dev);
+	struct gpio_dev_priv *uc_priv = dev->uclass_priv;
+
+	priv->base = dm_pci_map_bar(dev, PCI_BASE_ADDRESS_1, PCI_REGION_MEM);
+	if (!priv->base) {
+		debug("failed to map GPIO registers\n");
+		return -EINVAL;
+	}
+
+	uc_priv->gpio_count = 12;
+	uc_priv->bank_name = "eg20t";
+	return 0;
+}
+
+static const struct udevice_id eg20t_gpio_ids[] = {
+	{ .compatible = "intel,eg20t-gpio" },
+	{ }
+};
+
+U_BOOT_DRIVER(eg20t_gpio) = {
+	.name	= "eg20t-gpio",
+	.id	= UCLASS_GPIO,
+	.of_match = eg20t_gpio_ids,
+	.probe	= eg20t_gpio_probe,
+	.priv_auto_alloc_size = sizeof(struct eg20t_gpio_priv),
+	.ops	= &eg20t_gpio_ops,
+};
+
+static struct pci_device_id eg20t_gpio_supported[] = {
+	{ PCI_VENDOR_ID_INTEL, 0x8803 },
+	{ },
+};
+
+U_BOOT_PCI_DEVICE(eg20t_gpio, eg20t_gpio_supported);
-- 
2.34.1