[PATCH v2 1/5] mfd: intel_ehl_pse_gpio: Introduce Intel Elkhart Lake PSE GPIO and TIO

[Raag Jadav <raag.jadav@xxxxxxxxx>]

Intel Elkhart Lake Programmable Service Engine (PSE) includes two PCI
devices that expose two different capabilities of GPIO and Timed I/O
as a single PCI function through shared MMIO.

Signed-off-by: Raag Jadav <raag.jadav@xxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
 MAINTAINERS                      |   5 ++
 drivers/mfd/Kconfig              |  12 ++++
 drivers/mfd/Makefile             |   1 +
 drivers/mfd/intel_ehl_pse_gpio.c | 100 +++++++++++++++++++++++++++++++
 4 files changed, 118 insertions(+)
 create mode 100644 drivers/mfd/intel_ehl_pse_gpio.c

diff --git a/MAINTAINERS b/MAINTAINERS
index d4280facbe51..9077ab11478c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11643,6 +11643,11 @@ F:	drivers/gpio/gpio-sodaville.c
 F:	drivers/gpio/gpio-tangier.c
 F:	drivers/gpio/gpio-tangier.h
 
+INTEL GPIO MFD DRIVER
+M:	Raag Jadav <raag.jadav@xxxxxxxxx>
+S:	Supported
+F:	drivers/mfd/intel_ehl_pse_gpio.c
+
 INTEL GVT-g DRIVERS (Intel GPU Virtualization)
 M:	Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx>
 M:	Zhi Wang <zhi.wang.linux@xxxxxxxxx>
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 6b0682af6e32..36eac5245179 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -597,6 +597,18 @@ config MFD_HI655X_PMIC
 	help
 	  Select this option to enable Hisilicon hi655x series pmic driver.
 
+config MFD_INTEL_EHL_PSE_GPIO
+	tristate "Intel Elkhart Lake PSE GPIO MFD"
+	depends on PCI && (X86 || COMPILE_TEST)
+	select MFD_CORE
+	help
+	  This MFD provides support for GPIO and TIO that exist on Intel
+	  Elkhart Lake PSE as a single PCI device. It splits the two I/O
+	  devices to their respective I/O drivers.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called intel_ehl_pse_gpio.
+
 config MFD_INTEL_QUARK_I2C_GPIO
 	tristate "Intel Quark MFD I2C GPIO"
 	depends on PCI
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 9220eaf7cf12..8f7d257856db 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -196,6 +196,7 @@ obj-$(CONFIG_MFD_TIMBERDALE)    += timberdale.o
 obj-$(CONFIG_PMIC_ADP5520)	+= adp5520.o
 obj-$(CONFIG_MFD_ADP5585)	+= adp5585.o
 obj-$(CONFIG_MFD_KEMPLD)	+= kempld-core.o
+obj-$(CONFIG_MFD_INTEL_EHL_PSE_GPIO)	+= intel_ehl_pse_gpio.o
 obj-$(CONFIG_MFD_INTEL_QUARK_I2C_GPIO)	+= intel_quark_i2c_gpio.o
 obj-$(CONFIG_LPC_SCH)		+= lpc_sch.o
 obj-$(CONFIG_LPC_ICH)		+= lpc_ich.o
diff --git a/drivers/mfd/intel_ehl_pse_gpio.c b/drivers/mfd/intel_ehl_pse_gpio.c
new file mode 100644
index 000000000000..6a6ad1390a7b
--- /dev/null
+++ b/drivers/mfd/intel_ehl_pse_gpio.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Intel MFD driver for Elkhart Lake - Programmable Service Engine
+ * (PSE) GPIO & TIO
+ *
+ * Copyright (c) 2025 Intel Corporation
+ *
+ * Intel Elkhart Lake PSE includes two PCI devices that expose two
+ * different capabilities of GPIO and Timed I/O as a single PCI
+ * function through shared MMIO.
+ */
+
+#include <linux/array_size.h>
+#include <linux/ioport.h>
+#include <linux/mfd/core.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/stddef.h>
+
+#define PSE_GPIO_OFFSET		0x0000
+#define PSE_GPIO_SIZE		0x0134
+
+#define PSE_TIO_OFFSET		0x1000
+#define PSE_TIO_SIZE		0x06B0
+
+static struct resource ehl_pse_gpio_resources[] = {
+	DEFINE_RES_MEM(PSE_GPIO_OFFSET, PSE_GPIO_SIZE),
+	DEFINE_RES_IRQ(0),
+};
+
+static struct resource ehl_pse_tio_resources[] = {
+	DEFINE_RES_MEM(PSE_TIO_OFFSET, PSE_TIO_SIZE),
+	DEFINE_RES_IRQ(1),
+};
+
+static struct mfd_cell ehl_pse_gpio_devs[] = {
+	{
+		.name = "gpio-elkhartlake",
+		.num_resources = ARRAY_SIZE(ehl_pse_gpio_resources),
+		.resources = ehl_pse_gpio_resources,
+		.ignore_resource_conflicts = true,
+	},
+	{
+		.name = "pps-gen-tio",
+		.num_resources = ARRAY_SIZE(ehl_pse_tio_resources),
+		.resources = ehl_pse_tio_resources,
+		.ignore_resource_conflicts = true,
+	},
+};
+
+static int ehl_pse_gpio_probe(struct pci_dev *pci, const struct pci_device_id *id)
+{
+	int ret;
+
+	ret = pcim_enable_device(pci);
+	if (ret)
+		return ret;
+
+	pci_set_master(pci);
+
+	ret = pci_alloc_irq_vectors(pci, 2, 2, PCI_IRQ_ALL_TYPES);
+	if (ret < 0)
+		return ret;
+
+	ret = mfd_add_devices(&pci->dev, PLATFORM_DEVID_AUTO, ehl_pse_gpio_devs,
+			      ARRAY_SIZE(ehl_pse_gpio_devs), pci_resource_n(pci, 0),
+			      pci_irq_vector(pci, 0), NULL);
+	if (ret)
+		pci_free_irq_vectors(pci);
+
+	return ret;
+}
+
+static void ehl_pse_gpio_remove(struct pci_dev *pdev)
+{
+	mfd_remove_devices(&pdev->dev);
+	pci_free_irq_vectors(pdev);
+}
+
+static const struct pci_device_id ehl_pse_gpio_ids[] = {
+	{ PCI_VDEVICE(INTEL, 0x4b88) },
+	{ PCI_VDEVICE(INTEL, 0x4b89) },
+	{}
+};
+MODULE_DEVICE_TABLE(pci, ehl_pse_gpio_ids);
+
+static struct pci_driver ehl_pse_gpio_driver = {
+	.probe		= ehl_pse_gpio_probe,
+	.remove		= ehl_pse_gpio_remove,
+	.id_table	= ehl_pse_gpio_ids,
+	.name		= "ehl_pse_gpio",
+};
+module_pci_driver(ehl_pse_gpio_driver);
+
+MODULE_AUTHOR("Raymond Tan <raymond.tan@xxxxxxxxx>");
+MODULE_AUTHOR("Raag Jadav <raag.jadav@xxxxxxxxx>");
+MODULE_DESCRIPTION("Intel MFD for Elkhart Lake PSE GPIO & TIO");
+MODULE_LICENSE("GPL");
-- 
2.34.1