[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 1301cec94f128a43df44d41913725809d10c44cd..6c645a3c7360edbef022677545e5aa804bf3f3b1 100644 (file)
--- 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 9e40af196aae674dd6fa6bcee66971adbca54eee..84aa178f6b6501fa933d1ca07ad11e03ff923508 100644 (file)
--- 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 (file)
index 0000000..8dc23e0
--- /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");