[PATCH] gpio: Add driver for PC Engines APU2/APU3 GPIOs

[Florian Eckert <fe@dev.tdt.de>]

Add a new device driver "gpio-apu" which will now handle the GPIOs on
APU2 and APU3 devices from PC Engines.

- APU2/APU3 -> front button reset support
- APU3 -> SIM switch support

Signed-off-by: Florian Eckert <fe@dev.tdt.de>
---
 drivers/gpio/Kconfig    |  10 ++
 drivers/gpio/Makefile   |   1 +
 drivers/gpio/gpio-apu.c | 344 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 355 insertions(+)
 create mode 100644 drivers/gpio/gpio-apu.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 71c0ab46f216..9eb8977ba2e5 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -117,6 +117,16 @@ config GPIO_AMDPT
 	  driver for GPIO functionality on Promontory IOHub
 	  Require ACPI ASL code to enumerate as a platform device.
 
+config GPIO_APU
+	tristate "PC Engines APU2/APU3 GPIO support"
+	depends on X86
+	select GPIO_GENERIC
+	help
+	  Say Y here to support GPIO functionality on APU2/APU3 boards
+	  from PC Engines.
+	  - APU2/APU3 -> front button reset support
+	  - APU3 -> SIM switch support
+
 config GPIO_ASPEED
 	tristate "Aspeed GPIO support"
 	depends on (ARCH_ASPEED || COMPILE_TEST) && OF_GPIO
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 1324c8f966a7..feea4effcf29 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_GPIO_ALTERA)  	+= gpio-altera.o
 obj-$(CONFIG_GPIO_ALTERA_A10SR)	+= gpio-altera-a10sr.o
 obj-$(CONFIG_GPIO_AMD8111)	+= gpio-amd8111.o
 obj-$(CONFIG_GPIO_AMDPT)	+= gpio-amdpt.o
+obj-$(CONFIG_GPIO_APU)		+= gpio-apu.o
 obj-$(CONFIG_GPIO_ARIZONA)	+= gpio-arizona.o
 obj-$(CONFIG_GPIO_ATH79)	+= gpio-ath79.o
 obj-$(CONFIG_GPIO_ASPEED)	+= gpio-aspeed.o
diff --git a/drivers/gpio/gpio-apu.c b/drivers/gpio/gpio-apu.c
new file mode 100644
index 000000000000..18171c13917a
--- /dev/null
+++ b/drivers/gpio/gpio-apu.c
@@ -0,0 +1,344 @@
+/* PC Engines APU2/APU3 GPIO device driver
+ *
+ * Copyright (C) 2018 Florian Eckert <fe@dev.tdt.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version
+ *
+ * This program is distributed in the hope that it will be useful
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>
+ */
+
+#include <linux/dmi.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/gpio_keys.h>
+#include <linux/input.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#define DEVNAME                "gpio-apu"
+
+#define APU_FCH_ACPI_MMIO_BASE 0xFED80000
+#define APU_FCH_GPIO_BASE      (APU_FCH_ACPI_MMIO_BASE + 0x1500)
+#define APU_GPIO_BIT_WRITE     22
+#define APU_GPIO_BIT_READ      16
+#define APU_GPIO_BIT_DIR       23
+#define APU_IOSIZE             sizeof(u32)
+
+#define APU2_NUM_GPIO          1
+#define APU3_NUM_GPIO          2
+
+struct apu_gpio_pdata {
+	struct platform_device *pdev;
+	struct gpio_chip *chip;
+	unsigned long *offset;
+	void __iomem **addr;
+	int iosize; /* for devm_ioremap() */
+	spinlock_t lock;
+};
+
+static struct apu_gpio_pdata *apu_gpio;
+static struct platform_device *keydev;
+
+/* APU2 */
+static unsigned long apu2_gpio_offset[APU2_NUM_GPIO] = {
+	APU_FCH_GPIO_BASE + 89 * APU_IOSIZE, //KEY
+};
+static void __iomem *apu2_gpio_addr[APU2_NUM_GPIO] = {NULL};
+
+/* APU3 */
+static unsigned long apu3_gpio_offset[APU3_NUM_GPIO] = {
+	APU_FCH_GPIO_BASE + 89 * APU_IOSIZE, //KEY
+	APU_FCH_GPIO_BASE + 90 * APU_IOSIZE, //SIM
+};
+static void __iomem *apu3_gpio_addr[APU3_NUM_GPIO] = {NULL, NULL};
+
+static int gpio_apu_get_dir (struct gpio_chip *chip, unsigned offset)
+{
+	u32 val;
+
+	spin_lock(&apu_gpio->lock);
+
+	val = ~ioread32(apu_gpio->addr[offset]);
+	val = (val >> APU_GPIO_BIT_DIR) & 1;
+
+	spin_unlock(&apu_gpio->lock);
+
+	return val;
+}
+
+static int gpio_apu_dir_in (struct gpio_chip *chip, unsigned offset)
+{
+	u32 val;
+
+	spin_lock(&apu_gpio->lock);
+
+	val = ioread32(apu_gpio->addr[offset]);
+	val &= ~BIT(APU_GPIO_BIT_DIR);
+	iowrite32(val, apu_gpio->addr[offset]);
+
+	spin_unlock(&apu_gpio->lock);
+
+	return 0;
+}
+
+static int gpio_apu_dir_out (struct gpio_chip *chip, unsigned offset,
+		int value)
+{
+	u32 val;
+
+	spin_lock(&apu_gpio->lock);
+
+	val = ioread32(apu_gpio->addr[offset]);
+	val |= BIT(APU_GPIO_BIT_DIR);
+	iowrite32(val, apu_gpio->addr[offset]);
+
+	spin_unlock(&apu_gpio->lock);
+
+	return 0;
+}
+
+static int gpio_apu_get_data (struct gpio_chip *chip, unsigned offset)
+{
+	u32 val;
+
+	spin_lock(&apu_gpio->lock);
+
+	val = ioread32(apu_gpio->addr[offset]);
+	val = (val >> APU_GPIO_BIT_READ) & 1;
+
+	spin_unlock(&apu_gpio->lock);
+
+	return val;
+}
+
+static void gpio_apu_set_data (struct gpio_chip *chip, unsigned offset, int value)
+{
+	u32 val;
+
+	spin_lock(&apu_gpio->lock);
+
+	val = ioread32(apu_gpio->addr[offset]);
+	if (value)
+		val |= BIT(APU_GPIO_BIT_WRITE);
+	else
+		val &= ~BIT(APU_GPIO_BIT_WRITE);
+	iowrite32(val, apu_gpio->addr[offset]);
+
+	spin_unlock(&apu_gpio->lock);
+}
+
+static const struct dmi_system_id apu_gpio_dmi_table[] __initconst = {
+	/* PC Engines APU2 with "Legacy" bios < 4.0.8 */
+	{
+		.ident = "apu2",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "PC Engines"),
+			DMI_MATCH(DMI_BOARD_NAME, "APU2")
+		}
+	},
+	/* PC Engines APU2 with "Legacy" bios >= 4.0.8 */
+	{
+		.ident = "apu2",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "PC Engines"),
+			DMI_MATCH(DMI_BOARD_NAME, "apu2")
+		}
+	},
+	/* PC Engines APU2 with "Mainline" bios */
+	{
+		.ident = "apu2",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "PC Engines"),
+			DMI_MATCH(DMI_BOARD_NAME, "PC Engines apu2")
+		}
+	},
+	/* PC Engines APU3 with "Legancy" bios >= 4.0.7 */
+	{
+		.ident = "apu2",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "PC Engines"),
+			DMI_MATCH(DMI_BOARD_NAME, "APU3")
+		}
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(dmi, apu_gpio_dmi_table);
+
+static struct gpio_chip gpio_apu_chip = {
+	.label = "gpio-apu",
+	.owner = THIS_MODULE,
+	.base = -1,
+	.get_direction = gpio_apu_get_dir,
+	.direction_input = gpio_apu_dir_in,
+	.direction_output = gpio_apu_dir_out,
+	.get = gpio_apu_get_data,
+	.set = gpio_apu_set_data,
+};
+
+static struct gpio_keys_button apu_gpio_keys[] = {
+	{
+		.desc           = "Reset button",
+		.type           = EV_KEY,
+		.code           = KEY_RESTART,
+		.debounce_interval = 60,
+		.gpio           = 510,
+		.active_low     = 1,
+	},
+};
+
+static void register_gpio_keys_polled(int id, unsigned poll_interval,
+				      unsigned nbuttons,
+				      struct gpio_keys_button *buttons)
+{
+	struct gpio_keys_platform_data pdata = { };
+	int err;
+
+	keydev = platform_device_alloc("gpio-keys-polled", id);
+	if (!keydev) {
+		printk(KERN_ERR "Failed to allocate gpio-keys platform device\n");
+		return;
+	}
+
+	pdata.poll_interval = poll_interval;
+	pdata.nbuttons = nbuttons;
+	pdata.buttons = buttons;
+
+	err = platform_device_add_data(keydev, &pdata, sizeof(pdata));
+	if (err) {
+		dev_err(&keydev->dev, "failed to add platform data to key driver (%d)", err);
+		goto err_put_pdev;
+	}
+
+	err = platform_device_add(keydev);
+	if (err) {
+		dev_err(&keydev->dev, "failed to register key platform device (%d)", err);
+		goto err_put_pdev;
+	}
+
+	return;
+
+err_put_pdev:
+	platform_device_put(keydev);
+	keydev = NULL;
+}
+
+static int __init apu_gpio_probe(struct platform_device *pdev)
+{
+	int i;
+	int ret;
+
+	apu_gpio = devm_kzalloc(&pdev->dev, sizeof(*apu_gpio), GFP_KERNEL);
+
+	if (!apu_gpio)
+		return -ENOMEM;
+
+	apu_gpio->pdev = pdev;
+	apu_gpio->chip = &gpio_apu_chip;
+	spin_lock_init(&apu_gpio->lock);
+
+	if (dmi_match(DMI_PRODUCT_NAME, "APU3")) {
+		apu_gpio->offset = apu3_gpio_offset;
+		apu_gpio->addr = apu3_gpio_addr;
+		apu_gpio->iosize = APU_IOSIZE;
+		apu_gpio->chip->ngpio = ARRAY_SIZE(apu3_gpio_offset);
+		for( i = 0; i < ARRAY_SIZE(apu3_gpio_offset); i++) {
+			apu3_gpio_addr[i] = devm_ioremap(&pdev->dev,
+					apu_gpio->offset[i], apu_gpio->iosize);
+			if (!apu3_gpio_addr[i]) {
+				return -ENOMEM;
+			}
+		}
+	} else if (dmi_match(DMI_BOARD_NAME, "APU2") ||
+		   dmi_match(DMI_BOARD_NAME, "apu2") ||
+		   dmi_match(DMI_BOARD_NAME, "PC Engines apu2")) {
+		apu_gpio->offset = apu2_gpio_offset;
+		apu_gpio->addr = apu2_gpio_addr;
+		apu_gpio->iosize = APU_IOSIZE;
+		apu_gpio->chip->ngpio = ARRAY_SIZE(apu2_gpio_offset);
+		for( i = 0; i < ARRAY_SIZE(apu2_gpio_offset); i++) {
+			apu2_gpio_addr[i] = devm_ioremap(&pdev->dev,
+					apu_gpio->offset[i], apu_gpio->iosize);
+			if (!apu2_gpio_addr[i]) {
+				return -ENOMEM;
+			}
+		}
+	}
+
+	ret = gpiochip_add(&gpio_apu_chip);
+	if (ret) {
+		pr_err("Adding gpiochip failed\n");
+	}
+
+	register_gpio_keys_polled(-1, 20, ARRAY_SIZE(apu_gpio_keys), apu_gpio_keys);
+
+	return ret;
+}
+
+static struct platform_driver apu_gpio_driver = {
+	.driver = {
+		.name = KBUILD_MODNAME,
+	},
+};
+
+static int __init apu_gpio_init(void)
+{
+	struct platform_device *pdev;
+	int err;
+
+	if (!dmi_match(DMI_SYS_VENDOR, "PC Engines")) {
+		pr_err("No PC Engines board detected\n");
+		return -ENODEV;
+	}
+	if (!(dmi_match(DMI_PRODUCT_NAME, "APU") ||
+	      dmi_match(DMI_PRODUCT_NAME, "APU2") ||
+	      dmi_match(DMI_PRODUCT_NAME, "APU3") ||
+	      dmi_match(DMI_PRODUCT_NAME, "apu2") ||
+	      dmi_match(DMI_PRODUCT_NAME, "PC Engines apu2"))) {
+		pr_err("Unknown PC Engines board: %s\n",
+				dmi_get_system_info(DMI_PRODUCT_NAME));
+		return -ENODEV;
+	}
+
+	pdev = platform_device_register_simple(KBUILD_MODNAME, -1, NULL, 0);
+	if (IS_ERR(pdev)) {
+		pr_err("Device allocation failed\n");
+		return PTR_ERR(pdev);
+	}
+
+	err = platform_driver_probe(&apu_gpio_driver, apu_gpio_probe);
+	if (err) {
+		pr_err("Probe platform driver failed\n");
+		platform_device_unregister(pdev);
+	}
+
+	pr_info ("%s: APU2/3 GPIO driver module loaded\n", DEVNAME);
+
+	return err;
+}
+
+static void __exit apu_gpio_exit(void)
+{
+	platform_device_unregister(keydev);
+	gpiochip_remove(apu_gpio->chip);
+	platform_device_unregister(apu_gpio->pdev);
+	platform_driver_unregister(&apu_gpio_driver);
+	pr_info ("%s: APU2/3 GPIO driver module unloaded\n", DEVNAME);
+}
+
+module_init(apu_gpio_init);
+module_exit(apu_gpio_exit);
+
+MODULE_AUTHOR("Florian Eckert <fe@dev.tdt.de>");
+MODULE_DESCRIPTION("PC Engines APU2/APU3 family GPIO driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:gpio_apu");
-- 
2.11.0