From: Nikita Shubin <nikita.shubin@maquefel.me>
Date: Sun, 14 Apr 2024 12:23:49 +0000 (+0300)
Subject: [stage 0] gpio: pcie-edu: Add educational PCIE gpio driver
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=2595560869de18b6295cdd4282d186f827ad6e6f;p=linux.git

[stage 0] gpio: pcie-edu: Add educational PCIE gpio driver

Add educational PCIE gpio driver fully based on GPIO REGMAP,
driver supports every gpio operation with no iterrupt support.

Signed-off-by: Nikita Shubin <nikita.shubin@maquefel.me>
---

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 1301cec94f128..6c645a3c7360e 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -502,6 +502,16 @@ config GPIO_OMAP
 	help
 	  Say yes here to enable GPIO support for TI OMAP SoCs.
 
+config GPIO_PCIE_EDU
+	tristate "QEMU inter-machine comm edu GPIO support"
+	select REGMAP_IRQ
+	select REGMAP_MMIO
+	select GPIOLIB_IRQCHIP
+	select GPIO_REGMAP
+	help
+	  Say yes here to enable GPIO support for QEMU inter-machine
+	  comm edu.
+
 config GPIO_PL061
 	tristate "PrimeCell PL061 GPIO support"
 	depends on ARM_AMBA
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 9e40af196aae6..84aa178f6b650 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -122,6 +122,7 @@ obj-$(CONFIG_GPIO_OMAP)			+= gpio-omap.o
 obj-$(CONFIG_GPIO_PALMAS)		+= gpio-palmas.o
 obj-$(CONFIG_GPIO_PCA953X)		+= gpio-pca953x.o
 obj-$(CONFIG_GPIO_PCA9570)		+= gpio-pca9570.o
+obj-$(CONFIG_GPIO_PCIE_EDU)		+= gpio-pcie-edu.o
 obj-$(CONFIG_GPIO_PCF857X)		+= gpio-pcf857x.o
 obj-$(CONFIG_GPIO_PCH)			+= gpio-pch.o
 obj-$(CONFIG_GPIO_PCIE_IDIO_24)		+= gpio-pcie-idio-24.o
diff --git a/drivers/gpio/gpio-pcie-edu.c b/drivers/gpio/gpio-pcie-edu.c
new file mode 100644
index 0000000000000..8dc23e0458676
--- /dev/null
+++ b/drivers/gpio/gpio-pcie-edu.c
@@ -0,0 +1,105 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * GPIO driver for the QEMU inter-machine comm edu
+ * Copyright (C) 2024 Nikita Shubin
+ *
+ */
+#include <linux/bits.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio/regmap.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/regmap.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+#define GPIO_EDU_DATA		0x0
+#define GPIO_EDU_SET		0x1
+#define GPIO_EDU_CLEAR		0x2
+#define GPIO_EDU_DIROUT		0x3
+
+#define GPIO_EDU_PIN_STRIDE	0x10
+
+struct gpio_edu {
+	struct regmap *map;
+};
+
+static const struct regmap_config gpio_edu_regmap_config = {
+	.reg_bits = 8,
+	.reg_stride = 1,
+	.val_bits = 8,
+	.use_raw_spinlock = true,
+};
+
+static int gpio_edu_reg_mask_xlate(struct gpio_regmap *const gpio, const unsigned int base,
+				   const unsigned int offset, unsigned int *const reg,
+				   unsigned int *const mask)
+{
+	*mask = 0x1;
+	*reg  = base + (offset + 1) * GPIO_EDU_PIN_STRIDE;
+
+	return 0;
+}
+
+static int gpio_edu_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+	struct gpio_regmap_config gpio_config = {};
+	const char *const name = pci_name(pdev);
+	struct device *const dev = &pdev->dev;
+	void __iomem *gpio_edu_regs;
+	struct gpio_edu *gpioedu;
+	int err;
+
+	err = pcim_enable_device(pdev);
+	if (err)
+		return dev_err_probe(dev, err, "Failed to enable PCI device");
+
+	err = pcim_iomap_regions(pdev, BIT(0), name);
+	if (err)
+		return dev_err_probe(dev, err, "Unable to map PCI I/O addresses");
+
+	gpio_edu_regs = pcim_iomap_table(pdev)[0];
+
+	gpioedu = devm_kzalloc(dev, sizeof(*gpioedu), GFP_KERNEL);
+	if (!gpioedu)
+		return -ENOMEM;
+
+	gpioedu->map = devm_regmap_init_mmio(dev, gpio_edu_regs, &gpio_edu_regmap_config);
+	if (IS_ERR(gpioedu->map))
+		return dev_err_probe(dev, PTR_ERR(gpioedu->map),
+				     "Unable to initialize register map\n");
+
+	gpio_config.parent = dev;
+	gpio_config.regmap = gpioedu->map;
+	gpio_config.ngpio  = 8;
+	gpio_config.reg_dat_base = GPIO_REGMAP_ADDR(GPIO_EDU_DATA);
+	gpio_config.reg_set_base = GPIO_REGMAP_ADDR(GPIO_EDU_SET);
+	gpio_config.reg_clr_base = GPIO_REGMAP_ADDR(GPIO_EDU_CLEAR);
+	gpio_config.reg_dir_out_base = GPIO_REGMAP_ADDR(GPIO_EDU_DIROUT);
+	gpio_config.reg_mask_xlate = gpio_edu_reg_mask_xlate;
+	gpio_config.ngpio_per_reg = 1;
+	gpio_config.drvdata = gpioedu->map;
+
+	return PTR_ERR_OR_ZERO(devm_gpio_regmap_register(dev, &gpio_config));
+}
+
+static const struct pci_device_id gpio_edu_pci_dev_id[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_REDHAT_QUMRANET, 0x1111) },
+	{ 0 }
+};
+MODULE_DEVICE_TABLE(pci, gpio_edu_pci_dev_id);
+
+static struct pci_driver gpio_edu_driver = {
+	.name = "pcie-gpio-edu",
+	.id_table = gpio_edu_pci_dev_id,
+	.probe = gpio_edu_probe
+};
+
+module_pci_driver(gpio_edu_driver);
+
+MODULE_AUTHOR("Nikita Shubin <n.shubin@yadro.com>");
+MODULE_DESCRIPTION("PCIe-EDU GPIO driver");
+MODULE_LICENSE("GPL v2");