[PATCH 2/8] Add Advantech EIO GPIO driver
From: Ramiro Oliveira
Date: Fri Dec 12 2025 - 11:41:29 EST
This driver controls the GPIO component of the Advantech EIO chip.
Signed-off-by: Ramiro Oliveira <ramiro.oliveira@xxxxxxxxxxxxx>
---
MAINTAINERS | 1 +
drivers/gpio/Kconfig | 6 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-eio.c | 273 ++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 281 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index bd9279796c2f..359d4a13f212 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -619,6 +619,7 @@ F: drivers/platform/x86/adv_swbutton.c
ADVANTECH EIO DRIVER
M: Ramiro Oliveira <ramiro.oliveira@xxxxxxxxxxxxx>
S: Maintained
+F: drivers/gpio/gpio-eio.c
F: drivers/mfd/eio_core.c
F: include/linux/mfd/eio.h
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index bd185482a7fd..628a914842bd 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -277,6 +277,12 @@ config GPIO_DWAPB
Say Y or M here to build support for the Synopsys DesignWare APB
GPIO block.
+config GPIO_EIO
+ tristate "Advantech EIO GPIO"
+ depends on MFD_EIO
+ help
+ Say Y or M to build support for Advantech EIO GPIO block.
+
config GPIO_EIC_SPRD
tristate "Spreadtrum EIC support"
depends on ARCH_SPRD || COMPILE_TEST
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 2421a8fd3733..ba3883d5e4a0 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -64,6 +64,7 @@ obj-$(CONFIG_GPIO_DLN2) += gpio-dln2.o
obj-$(CONFIG_GPIO_DS4520) += gpio-ds4520.o
obj-$(CONFIG_GPIO_DWAPB) += gpio-dwapb.o
obj-$(CONFIG_GPIO_EIC_SPRD) += gpio-eic-sprd.o
+obj-$(CONFIG_GPIO_EIO) += gpio-eio.o
obj-$(CONFIG_GPIO_ELKHARTLAKE) += gpio-elkhartlake.o
obj-$(CONFIG_GPIO_EM) += gpio-em.o
obj-$(CONFIG_GPIO_EN7523) += gpio-en7523.o
diff --git a/drivers/gpio/gpio-eio.c b/drivers/gpio/gpio-eio.c
new file mode 100644
index 000000000000..50f66a325e8f
--- /dev/null
+++ b/drivers/gpio/gpio-eio.c
@@ -0,0 +1,273 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * GPIO driver for Advantech EIO Embedded controller.
+ *
+ * Copyright (C) 2025 Advantech Corporation. All rights reserved.
+ */
+
+#include <linux/errno.h>
+#include <linux/gpio.h>
+#include <linux/gpio/driver.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/eio.h>
+#include <linux/module.h>
+
+#define GPIO_MAX_PINS 48
+#define GPIO_WRITE 0x18
+#define GPIO_READ 0x19
+
+struct eio_gpio_dev {
+ u64 avail;
+ int max;
+ struct gpio_chip chip;
+ struct device *dev;
+};
+
+struct {
+ int size;
+ bool write;
+} ctrl_para[] = {
+ { 0x01, false }, { 0x00, false }, { 0x00, false }, { 0x02, false },
+ { 0x01, false }, { 0x00, false }, { 0x00, false }, { 0x00, false },
+ { 0x00, false }, { 0x00, false }, { 0x00, false }, { 0x00, false },
+ { 0x00, false }, { 0x00, false }, { 0x00, false }, { 0x00, false },
+ { 0x01, true }, { 0x01, true }, { 0x02, true }, { 0x02, true },
+ { 0x02, false }, { 0x10, false }
+};
+
+enum {
+ GPIO_STATUS = 0,
+ GPIO_GROUP_AVAIL = 3,
+ GPIO_ERROR = 0x04,
+ GPIO_PIN_DIR = 0x10,
+ GPIO_PIN_LEVEL = 0x11,
+ GPIO_GROUP_DIR = 0x12,
+ GPIO_GROUP_LEVEL = 0x13,
+ GPIO_MAPPING = 0x14,
+ GPIO_NAME = 0x15
+} gpio_ctrl;
+
+struct {
+ int group;
+ int port;
+} group_map[] = {
+ { 0, 0 }, { 0, 1 },
+ { 1, 0 }, { 1, 1 },
+ { 2, 0 }, { 2, 1 },
+ { 3, 0 }, { 3, 1 },
+ { 3, 2 }, { 3, 3 },
+ { 3, 4 }, { 3, 5 },
+ { 3, 6 }, { 3, 7 }
+};
+
+static int timeout;
+module_param(timeout, int, 0444);
+MODULE_PARM_DESC(timeout, "Set PMC command timeout value.\n");
+
+static int pmc_write(struct device *mfd_dev, u8 ctrl, u8 dev_id, void *data)
+{
+ struct pmc_op op = {
+ .cmd = GPIO_WRITE,
+ .control = ctrl,
+ .device_id = dev_id,
+ .payload = (u8 *)data,
+ .timeout = timeout,
+ };
+
+ if (ctrl > ARRAY_SIZE(ctrl_para))
+ return -ENOMEM;
+
+ if (!ctrl_para[ctrl].write)
+ return -EINVAL;
+
+ op.size = ctrl_para[ctrl].size;
+
+ return eio_core_pmc_operation(mfd_dev, &op);
+}
+
+static int pmc_read(struct device *mfd_dev, u8 ctrl, u8 dev_id, void *data)
+{
+ struct pmc_op op = {
+ .cmd = GPIO_READ,
+ .control = ctrl,
+ .device_id = dev_id,
+ .payload = (u8 *)data,
+ .timeout = timeout,
+ };
+
+ if (ctrl > ARRAY_SIZE(ctrl_para))
+ return -ENOMEM;
+
+ op.size = ctrl_para[ctrl].size;
+
+ return eio_core_pmc_operation(mfd_dev, &op);
+}
+
+static int get_dir(struct gpio_chip *chip, unsigned int offset)
+{
+ u8 dir;
+ int ret;
+
+ ret = pmc_read(chip->parent, GPIO_PIN_DIR, offset, &dir);
+ if (ret)
+ return ret;
+
+ return dir ? 0 : 1;
+}
+
+static int dir_input(struct gpio_chip *chip, unsigned int offset)
+{
+ u8 dir = 0;
+
+ return pmc_write(chip->parent, GPIO_PIN_DIR, offset, &dir);
+}
+
+static int dir_output(struct gpio_chip *chip, unsigned int offset, int value)
+{
+ u8 dir = 1;
+ u8 val = value;
+
+ pmc_write(chip->parent, GPIO_PIN_DIR, offset, &dir);
+
+ return pmc_write(chip->parent, GPIO_PIN_LEVEL, offset, &val);
+}
+
+static int gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+ u8 level;
+ int ret;
+
+ ret = pmc_read(chip->parent, GPIO_PIN_LEVEL, offset, &level);
+ if (ret)
+ return ret;
+
+ return level;
+}
+
+static int gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
+{
+ u8 val = value;
+
+ pmc_write(chip->parent, GPIO_PIN_LEVEL, offset, &val);
+
+ return 0;
+}
+
+static int check_support(struct device *dev)
+{
+ u8 data;
+ int ret;
+
+ ret = pmc_read(dev, GPIO_STATUS, 0, &data);
+ if (!ret)
+ return ret;
+
+ if ((data & 0x01) == 0)
+ return -EOPNOTSUPP;
+
+ return 0;
+}
+
+static int check_pin(struct device *dev, int pin)
+{
+ int ret;
+ int group, bit;
+ u16 data;
+
+ /* Get pin mapping */
+ ret = pmc_read(dev, GPIO_MAPPING, pin, &data);
+ if (ret)
+ return ret;
+
+ if ((data & 0xFF) > ARRAY_SIZE(group_map))
+ return -EINVAL;
+
+ group = group_map[data & 0xFF].group;
+ bit = data >> 8;
+
+ /* Check mapped pin */
+ ret = pmc_read(dev, GPIO_GROUP_AVAIL, group, &data);
+ if (ret)
+ return ret;
+
+ return data & BIT(bit) ? 0 : -EOPNOTSUPP;
+}
+
+static int gpio_init(struct device *mfd, struct eio_gpio_dev *eio_gpio)
+{
+ int ret;
+ int i;
+ char str[GPIO_MAX_PINS + 1];
+
+ memset(str, 0x30, sizeof(str));
+
+ ret = check_support(mfd);
+ if (ret) {
+ dev_err(eio_gpio->dev, "GPIO not supported (%d)\n", ret);
+ return ret;
+ }
+
+ eio_gpio->avail = 0;
+
+ for (i = 0 ; i < GPIO_MAX_PINS ; i++) {
+ ret = check_pin(mfd, i);
+ if (ret)
+ continue;
+
+ eio_gpio->avail |= BIT(i);
+ eio_gpio->max = i + 1;
+ str[GPIO_MAX_PINS - i] = '1';
+ }
+
+ dev_info(eio_gpio->dev, "GPIO pins=%s\n", str);
+
+ return eio_gpio->max ? 0 : -EOPNOTSUPP;
+}
+
+static const struct gpio_chip eio_gpio_chip = {
+ .label = KBUILD_MODNAME,
+ .owner = THIS_MODULE,
+ .direction_input = dir_input,
+ .get = gpio_get,
+ .direction_output = dir_output,
+ .set = gpio_set,
+ .get_direction = get_dir,
+ .base = -1,
+ .can_sleep = true,
+};
+
+static int gpio_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct eio_gpio_dev *eio_gpio;
+ struct eio_dev *eio_dev = dev_get_drvdata(dev->parent);
+
+ if (!eio_dev) {
+ dev_err(dev, "Error contact eio_core\n");
+ return -ENODEV;
+ }
+
+ eio_gpio = devm_kzalloc(dev, sizeof(*eio_gpio), GFP_KERNEL);
+ eio_gpio->dev = dev;
+
+ if (gpio_init(dev->parent, eio_gpio))
+ return -EIO;
+
+ eio_gpio->chip = eio_gpio_chip;
+ eio_gpio->chip.parent = dev->parent;
+ eio_gpio->chip.ngpio = eio_gpio->max;
+
+ return devm_gpiochip_add_data(dev, &eio_gpio->chip, eio_gpio);
+}
+
+static struct platform_driver gpio_driver = {
+ .probe = gpio_probe,
+ .driver = { .name = KBUILD_MODNAME, },
+};
+
+module_platform_driver(gpio_driver);
+
+MODULE_AUTHOR("Wenkai Chung <wenkai.chung@xxxxxxxxxxxxxxxx>");
+MODULE_AUTHOR("Ramiro Oliveira <ramiro.oliveira@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("GPIO driver for Advantech EIO embedded controller");
+MODULE_LICENSE("GPL");
--
2.43.0