--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * GPIO interface for Winbond Super I/O chips
+ * Currently, only W83627UHG (Nuvoton NCT6627UD) is supported.
+ *
+ * Author: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/gpio/driver.h>
+#include <linux/ioport.h>
+#include <linux/isa.h>
+#include <linux/module.h>
+
+#define WB_GPIO_DRIVER_NAME            KBUILD_MODNAME
+
+#define WB_SIO_BASE                    0x2e
+#define WB_SIO_BASE_HIGH               0x4e
+
+#define WB_SIO_EXT_ENTER_KEY           0x87
+#define WB_SIO_EXT_EXIT_KEY            0xaa
+
+/* global chip registers */
+
+#define WB_SIO_REG_LOGICAL             0x07
+
+#define WB_SIO_REG_CHIP_MSB            0x20
+#define WB_SIO_REG_CHIP_LSB            0x21
+
+#define WB_SIO_CHIP_ID_W83627UHG       0xa230
+#define WB_SIO_CHIP_ID_W83627UHG_MASK  GENMASK(15, 4)
+
+#define WB_SIO_REG_DPD                 0x22
+#define WB_SIO_REG_DPD_UARTA           4
+#define WB_SIO_REG_DPD_UARTB           5
+
+#define WB_SIO_REG_IDPD                0x23
+#define WB_SIO_REG_IDPD_UARTC          4
+#define WB_SIO_REG_IDPD_UARTD          5
+#define WB_SIO_REG_IDPD_UARTE          6
+#define WB_SIO_REG_IDPD_UARTF          7
+
+#define WB_SIO_REG_GLOBAL_OPT          0x24
+#define WB_SIO_REG_GO_ENFDC            1
+
+#define WB_SIO_REG_OVTGPIO3456         0x29
+#define WB_SIO_REG_OG3456_G3PP         3
+#define WB_SIO_REG_OG3456_G4PP         4
+#define WB_SIO_REG_OG3456_G5PP         5
+#define WB_SIO_REG_OG3456_G6PP         7
+
+#define WB_SIO_REG_I2C_PS              0x2a
+#define WB_SIO_REG_I2CPS_I2CFS         1
+
+#define WB_SIO_REG_GPIO1_MF            0x2c
+#define WB_SIO_REG_G1MF_G1PP           6
+#define WB_SIO_REG_G1MF_G2PP           7
+#define WB_SIO_REG_G1MF_FS_MASK        GENMASK(1, 0)
+#define WB_SIO_REG_G1MF_FS_IR_OFF      0
+#define WB_SIO_REG_G1MF_FS_IR          1
+#define WB_SIO_REG_G1MF_FS_GPIO1       2
+#define WB_SIO_REG_G1MF_FS_UARTB       3
+
+/* not an actual device number, just a value meaning 'no device' */
+#define WB_SIO_DEV_NONE                0xff
+
+/* registers with offsets >= 0x30 are specific for a particular device */
+
+/* UART B logical device */
+#define WB_SIO_DEV_UARTB               0x03
+#define WB_SIO_UARTB_REG_ENABLE        0x30
+#define WB_SIO_UARTB_ENABLE_ON         0
+
+/* UART C logical device */
+#define WB_SIO_DEV_UARTC               0x06
+#define WB_SIO_UARTC_REG_ENABLE        0x30
+#define WB_SIO_UARTC_ENABLE_ON         0
+
+/* GPIO3, GPIO4 logical device */
+#define WB_SIO_DEV_GPIO34              0x07
+#define WB_SIO_GPIO34_REG_ENABLE       0x30
+#define WB_SIO_GPIO34_ENABLE_3         0
+#define WB_SIO_GPIO34_ENABLE_4         1
+#define WB_SIO_GPIO34_REG_IO3          0xe0
+#define WB_SIO_GPIO34_REG_DATA3        0xe1
+#define WB_SIO_GPIO34_REG_INV3         0xe2
+#define WB_SIO_GPIO34_REG_IO4          0xe4
+#define WB_SIO_GPIO34_REG_DATA4        0xe5
+#define WB_SIO_GPIO34_REG_INV4         0xe6
+
+/* WDTO, PLED, GPIO5, GPIO6 logical device */
+#define WB_SIO_DEV_WDGPIO56            0x08
+#define WB_SIO_WDGPIO56_REG_ENABLE     0x30
+#define WB_SIO_WDGPIO56_ENABLE_5       1
+#define WB_SIO_WDGPIO56_ENABLE_6       2
+#define WB_SIO_WDGPIO56_REG_IO5        0xe0
+#define WB_SIO_WDGPIO56_REG_DATA5      0xe1
+#define WB_SIO_WDGPIO56_REG_INV5       0xe2
+#define WB_SIO_WDGPIO56_REG_IO6        0xe4
+#define WB_SIO_WDGPIO56_REG_DATA6      0xe5
+#define WB_SIO_WDGPIO56_REG_INV6       0xe6
+
+/* GPIO1, GPIO2, SUSLED logical device */
+#define WB_SIO_DEV_GPIO12              0x09
+#define WB_SIO_GPIO12_REG_ENABLE       0x30
+#define WB_SIO_GPIO12_ENABLE_1         0
+#define WB_SIO_GPIO12_ENABLE_2         1
+#define WB_SIO_GPIO12_REG_IO1          0xe0
+#define WB_SIO_GPIO12_REG_DATA1        0xe1
+#define WB_SIO_GPIO12_REG_INV1         0xe2
+#define WB_SIO_GPIO12_REG_IO2          0xe4
+#define WB_SIO_GPIO12_REG_DATA2        0xe5
+#define WB_SIO_GPIO12_REG_INV2         0xe6
+
+/* UART D logical device */
+#define WB_SIO_DEV_UARTD               0x0d
+#define WB_SIO_UARTD_REG_ENABLE        0x30
+#define WB_SIO_UARTD_ENABLE_ON         0
+
+/* UART E logical device */
+#define WB_SIO_DEV_UARTE               0x0e
+#define WB_SIO_UARTE_REG_ENABLE        0x30
+#define WB_SIO_UARTE_ENABLE_ON         0
+
+/*
+ * for a description what a particular field of this struct means please see
+ * a description of the relevant module parameter at the bottom of this file
+ */
+struct winbond_gpio_params {
+       unsigned long base;
+       unsigned long gpios;
+       unsigned long ppgpios;
+       unsigned long odgpios;
+       bool pledgpio;
+       bool beepgpio;
+       bool i2cgpio;
+};
+
+static struct winbond_gpio_params params;
+
+static int winbond_sio_enter(unsigned long base)
+{
+       if (!request_muxed_region(base, 2, WB_GPIO_DRIVER_NAME))
+               return -EBUSY;
+
+       /*
+        * datasheet says two successive writes of the "key" value are needed
+        * in order for chip to enter the "Extended Function Mode"
+        */
+       outb(WB_SIO_EXT_ENTER_KEY, base);
+       outb(WB_SIO_EXT_ENTER_KEY, base);
+
+       return 0;
+}
+
+static void winbond_sio_select_logical(unsigned long base, u8 dev)
+{
+       outb(WB_SIO_REG_LOGICAL, base);
+       outb(dev, base + 1);
+}
+
+static void winbond_sio_leave(unsigned long base)
+{
+       outb(WB_SIO_EXT_EXIT_KEY, base);
+
+       release_region(base, 2);
+}
+
+static void winbond_sio_reg_write(unsigned long base, u8 reg, u8 data)
+{
+       outb(reg, base);
+       outb(data, base + 1);
+}
+
+static u8 winbond_sio_reg_read(unsigned long base, u8 reg)
+{
+       outb(reg, base);
+       return inb(base + 1);
+}
+
+static void winbond_sio_reg_bset(unsigned long base, u8 reg, u8 bit)
+{
+       u8 val;
+
+       val = winbond_sio_reg_read(base, reg);
+       val |= BIT(bit);
+       winbond_sio_reg_write(base, reg, val);
+}
+
+static void winbond_sio_reg_bclear(unsigned long base, u8 reg, u8 bit)
+{
+       u8 val;
+
+       val = winbond_sio_reg_read(base, reg);
+       val &= ~BIT(bit);
+       winbond_sio_reg_write(base, reg, val);
+}
+
+static bool winbond_sio_reg_btest(unsigned long base, u8 reg, u8 bit)
+{
+       return winbond_sio_reg_read(base, reg) & BIT(bit);
+}
+
+/**
+ * struct winbond_gpio_port_conflict - possibly conflicting device information
+ * @name:      device name (NULL means no conflicting device defined)
+ * @dev:       Super I/O logical device number where the testreg register
+ *             is located (or WB_SIO_DEV_NONE - don't select any
+ *             logical device)
+ * @testreg:   register number where the testbit bit is located
+ * @testbit:   index of a bit to check whether an actual conflict exists
+ * @warnonly:  if set then a conflict isn't fatal (just warn about it),
+ *             otherwise disable the particular GPIO port if a conflict
+ *             is detected
+ */
+struct winbond_gpio_port_conflict {
+       const char *name;
+       u8 dev;
+       u8 testreg;
+       u8 testbit;
+       bool warnonly;
+};
+
+/**
+ * struct winbond_gpio_info - information about a particular GPIO port (device)
+ * @dev:               Super I/O logical device number of the registers
+ *                     specified below
+ * @enablereg:         port enable bit register number
+ * @enablebit:         index of a port enable bit
+ * @outputreg:         output driver mode bit register number
+ * @outputppbit:       index of a push-pull output driver mode bit
+ * @ioreg:             data direction register number
+ * @invreg:            pin data inversion register number
+ * @datareg:           pin data register number
+ * @conflict:          description of a device that possibly conflicts with
+ *                     this port
+ */
+struct winbond_gpio_info {
+       u8 dev;
+       u8 enablereg;
+       u8 enablebit;
+       u8 outputreg;
+       u8 outputppbit;
+       u8 ioreg;
+       u8 invreg;
+       u8 datareg;
+       struct winbond_gpio_port_conflict conflict;
+};
+
+static const struct winbond_gpio_info winbond_gpio_infos[6] = {
+       { /* 0 */
+               .dev = WB_SIO_DEV_GPIO12,
+               .enablereg = WB_SIO_GPIO12_REG_ENABLE,
+               .enablebit = WB_SIO_GPIO12_ENABLE_1,
+               .outputreg = WB_SIO_REG_GPIO1_MF,
+               .outputppbit = WB_SIO_REG_G1MF_G1PP,
+               .ioreg = WB_SIO_GPIO12_REG_IO1,
+               .invreg = WB_SIO_GPIO12_REG_INV1,
+               .datareg = WB_SIO_GPIO12_REG_DATA1,
+               .conflict = {
+                       .name = "UARTB",
+                       .dev = WB_SIO_DEV_UARTB,
+                       .testreg = WB_SIO_UARTB_REG_ENABLE,
+                       .testbit = WB_SIO_UARTB_ENABLE_ON,
+                       .warnonly = true
+               }
+       },
+       { /* 1 */
+               .dev = WB_SIO_DEV_GPIO12,
+               .enablereg = WB_SIO_GPIO12_REG_ENABLE,
+               .enablebit = WB_SIO_GPIO12_ENABLE_2,
+               .outputreg = WB_SIO_REG_GPIO1_MF,
+               .outputppbit = WB_SIO_REG_G1MF_G2PP,
+               .ioreg = WB_SIO_GPIO12_REG_IO2,
+               .invreg = WB_SIO_GPIO12_REG_INV2,
+               .datareg = WB_SIO_GPIO12_REG_DATA2
+               /* special conflict handling so doesn't use conflict data */
+       },
+       { /* 2 */
+               .dev = WB_SIO_DEV_GPIO34,
+               .enablereg = WB_SIO_GPIO34_REG_ENABLE,
+               .enablebit = WB_SIO_GPIO34_ENABLE_3,
+               .outputreg = WB_SIO_REG_OVTGPIO3456,
+               .outputppbit = WB_SIO_REG_OG3456_G3PP,
+               .ioreg = WB_SIO_GPIO34_REG_IO3,
+               .invreg = WB_SIO_GPIO34_REG_INV3,
+               .datareg = WB_SIO_GPIO34_REG_DATA3,
+               .conflict = {
+                       .name = "UARTC",
+                       .dev = WB_SIO_DEV_UARTC,
+                       .testreg = WB_SIO_UARTC_REG_ENABLE,
+                       .testbit = WB_SIO_UARTC_ENABLE_ON,
+                       .warnonly = true
+               }
+       },
+       { /* 3 */
+               .dev = WB_SIO_DEV_GPIO34,
+               .enablereg = WB_SIO_GPIO34_REG_ENABLE,
+               .enablebit = WB_SIO_GPIO34_ENABLE_4,
+               .outputreg = WB_SIO_REG_OVTGPIO3456,
+               .outputppbit = WB_SIO_REG_OG3456_G4PP,
+               .ioreg = WB_SIO_GPIO34_REG_IO4,
+               .invreg = WB_SIO_GPIO34_REG_INV4,
+               .datareg = WB_SIO_GPIO34_REG_DATA4,
+               .conflict = {
+                       .name = "UARTD",
+                       .dev = WB_SIO_DEV_UARTD,
+                       .testreg = WB_SIO_UARTD_REG_ENABLE,
+                       .testbit = WB_SIO_UARTD_ENABLE_ON,
+                       .warnonly = true
+               }
+       },
+       { /* 4 */
+               .dev = WB_SIO_DEV_WDGPIO56,
+               .enablereg = WB_SIO_WDGPIO56_REG_ENABLE,
+               .enablebit = WB_SIO_WDGPIO56_ENABLE_5,
+               .outputreg = WB_SIO_REG_OVTGPIO3456,
+               .outputppbit = WB_SIO_REG_OG3456_G5PP,
+               .ioreg = WB_SIO_WDGPIO56_REG_IO5,
+               .invreg = WB_SIO_WDGPIO56_REG_INV5,
+               .datareg = WB_SIO_WDGPIO56_REG_DATA5,
+               .conflict = {
+                       .name = "UARTE",
+                       .dev = WB_SIO_DEV_UARTE,
+                       .testreg = WB_SIO_UARTE_REG_ENABLE,
+                       .testbit = WB_SIO_UARTE_ENABLE_ON,
+                       .warnonly = true
+               }
+       },
+       { /* 5 */
+               .dev = WB_SIO_DEV_WDGPIO56,
+               .enablereg = WB_SIO_WDGPIO56_REG_ENABLE,
+               .enablebit = WB_SIO_WDGPIO56_ENABLE_6,
+               .outputreg = WB_SIO_REG_OVTGPIO3456,
+               .outputppbit = WB_SIO_REG_OG3456_G6PP,
+               .ioreg = WB_SIO_WDGPIO56_REG_IO6,
+               .invreg = WB_SIO_WDGPIO56_REG_INV6,
+               .datareg = WB_SIO_WDGPIO56_REG_DATA6,
+               .conflict = {
+                       .name = "FDC",
+                       .dev = WB_SIO_DEV_NONE,
+                       .testreg = WB_SIO_REG_GLOBAL_OPT,
+                       .testbit = WB_SIO_REG_GO_ENFDC,
+                       .warnonly = false
+               }
+       }
+};
+
+/* returns whether changing a pin is allowed */
+static bool winbond_gpio_get_info(unsigned int *gpio_num,
+                                 const struct winbond_gpio_info **info)
+{
+       bool allow_changing = true;
+       unsigned long i;
+
+       for_each_set_bit(i, ¶ms.gpios, BITS_PER_LONG) {
+               if (*gpio_num < 8)
+                       break;
+
+               *gpio_num -= 8;
+       }
+
+       *info = &winbond_gpio_infos[i];
+
+       /*
+        * GPIO2 (the second port) shares some pins with a basic PC
+        * functionality, which is very likely controlled by the firmware.
+        * Don't allow changing these pins by default.
+        */
+       if (i == 1) {
+               if (*gpio_num == 0 && !params.pledgpio)
+                       allow_changing = false;
+               else if (*gpio_num == 1 && !params.beepgpio)
+                       allow_changing = false;
+               else if ((*gpio_num == 5 || *gpio_num == 6) && !params.i2cgpio)
+                       allow_changing = false;
+       }
+
+       return allow_changing;
+}
+
+static int winbond_gpio_get(struct gpio_chip *gc, unsigned int offset)
+{
+       unsigned long *base = gpiochip_get_data(gc);
+       const struct winbond_gpio_info *info;
+       bool val;
+
+       winbond_gpio_get_info(&offset, &info);
+
+       val = winbond_sio_enter(*base);
+       if (val)
+               return val;
+
+       winbond_sio_select_logical(*base, info->dev);
+
+       val = winbond_sio_reg_btest(*base, info->datareg, offset);
+       if (winbond_sio_reg_btest(*base, info->invreg, offset))
+               val = !val;
+
+       winbond_sio_leave(*base);
+
+       return val;
+}
+
+static int winbond_gpio_direction_in(struct gpio_chip *gc, unsigned int offset)
+{
+       unsigned long *base = gpiochip_get_data(gc);
+       const struct winbond_gpio_info *info;
+       int ret;
+
+       if (!winbond_gpio_get_info(&offset, &info))
+               return -EACCES;
+
+       ret = winbond_sio_enter(*base);
+       if (ret)
+               return ret;
+
+       winbond_sio_select_logical(*base, info->dev);
+
+       winbond_sio_reg_bset(*base, info->ioreg, offset);
+
+       winbond_sio_leave(*base);
+
+       return 0;
+}
+
+static int winbond_gpio_direction_out(struct gpio_chip *gc,
+                                     unsigned int offset,
+                                     int val)
+{
+       unsigned long *base = gpiochip_get_data(gc);
+       const struct winbond_gpio_info *info;
+       int ret;
+
+       if (!winbond_gpio_get_info(&offset, &info))
+               return -EACCES;
+
+       ret = winbond_sio_enter(*base);
+       if (ret)
+               return ret;
+
+       winbond_sio_select_logical(*base, info->dev);
+
+       winbond_sio_reg_bclear(*base, info->ioreg, offset);
+
+       if (winbond_sio_reg_btest(*base, info->invreg, offset))
+               val = !val;
+
+       if (val)
+               winbond_sio_reg_bset(*base, info->datareg, offset);
+       else
+               winbond_sio_reg_bclear(*base, info->datareg, offset);
+
+       winbond_sio_leave(*base);
+
+       return 0;
+}
+
+static void winbond_gpio_set(struct gpio_chip *gc, unsigned int offset,
+                            int val)
+{
+       unsigned long *base = gpiochip_get_data(gc);
+       const struct winbond_gpio_info *info;
+
+       if (!winbond_gpio_get_info(&offset, &info))
+               return;
+
+       if (winbond_sio_enter(*base) != 0)
+               return;
+
+       winbond_sio_select_logical(*base, info->dev);
+
+       if (winbond_sio_reg_btest(*base, info->invreg, offset))
+               val = !val;
+
+       if (val)
+               winbond_sio_reg_bset(*base, info->datareg, offset);
+       else
+               winbond_sio_reg_bclear(*base, info->datareg, offset);
+
+       winbond_sio_leave(*base);
+}
+
+static struct gpio_chip winbond_gpio_chip = {
+       .base                   = -1,
+       .label                  = WB_GPIO_DRIVER_NAME,
+       .owner                  = THIS_MODULE,
+       .can_sleep              = true,
+       .get                    = winbond_gpio_get,
+       .direction_input        = winbond_gpio_direction_in,
+       .set                    = winbond_gpio_set,
+       .direction_output       = winbond_gpio_direction_out,
+};
+
+static void winbond_gpio_configure_port0_pins(unsigned long base)
+{
+       unsigned int val;
+
+       val = winbond_sio_reg_read(base, WB_SIO_REG_GPIO1_MF);
+       if ((val & WB_SIO_REG_G1MF_FS_MASK) == WB_SIO_REG_G1MF_FS_GPIO1)
+               return;
+
+       pr_warn("GPIO1 pins were connected to something else (%.2x), fixing\n",
+               val);
+
+       val &= ~WB_SIO_REG_G1MF_FS_MASK;
+       val |= WB_SIO_REG_G1MF_FS_GPIO1;
+
+       winbond_sio_reg_write(base, WB_SIO_REG_GPIO1_MF, val);
+}
+
+static void winbond_gpio_configure_port1_check_i2c(unsigned long base)
+{
+       params.i2cgpio = !winbond_sio_reg_btest(base, WB_SIO_REG_I2C_PS,
+                                               WB_SIO_REG_I2CPS_I2CFS);
+       if (!params.i2cgpio)
+               pr_warn("disabling GPIO2.5 and GPIO2.6 as I2C is enabled\n");
+}
+
+static bool winbond_gpio_configure_port(unsigned long base, unsigned int idx)
+{
+       const struct winbond_gpio_info *info = &winbond_gpio_infos[idx];
+       const struct winbond_gpio_port_conflict *conflict = &info->conflict;
+
+       /* is there a possible conflicting device defined? */
+       if (conflict->name != NULL) {
+               if (conflict->dev != WB_SIO_DEV_NONE)
+                       winbond_sio_select_logical(base, conflict->dev);
+
+               if (winbond_sio_reg_btest(base, conflict->testreg,
+                                         conflict->testbit)) {
+                       if (conflict->warnonly)
+                               pr_warn("enabled GPIO%u share pins with active %s\n",
+                                       idx + 1, conflict->name);
+                       else {
+                               pr_warn("disabling GPIO%u as %s is enabled\n",
+                                       idx + 1, conflict->name);
+                               return false;
+                       }
+               }
+       }
+
+       /* GPIO1 and GPIO2 need some (additional) special handling */
+       if (idx == 0)
+               winbond_gpio_configure_port0_pins(base);
+       else if (idx == 1)
+               winbond_gpio_configure_port1_check_i2c(base);
+
+       winbond_sio_select_logical(base, info->dev);
+
+       winbond_sio_reg_bset(base, info->enablereg, info->enablebit);
+
+       if (params.ppgpios & BIT(idx))
+               winbond_sio_reg_bset(base, info->outputreg,
+                                    info->outputppbit);
+       else if (params.odgpios & BIT(idx))
+               winbond_sio_reg_bclear(base, info->outputreg,
+                                      info->outputppbit);
+       else
+               pr_notice("GPIO%u pins are %s\n", idx + 1,
+                         winbond_sio_reg_btest(base, info->outputreg,
+                                               info->outputppbit) ?
+                         "push-pull" :
+                         "open drain");
+
+       return true;
+}
+
+static int winbond_gpio_configure(unsigned long base)
+{
+       unsigned long i;
+
+       for_each_set_bit(i, ¶ms.gpios, BITS_PER_LONG)
+               if (!winbond_gpio_configure_port(base, i))
+                       __clear_bit(i, ¶ms.gpios);
+
+       if (!params.gpios) {
+               pr_err("please use 'gpios' module parameter to select some active GPIO ports to enable\n");
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+static int winbond_gpio_check_chip(unsigned long base)
+{
+       int ret;
+       unsigned int chip;
+
+       ret = winbond_sio_enter(base);
+       if (ret)
+               return ret;
+
+       chip = winbond_sio_reg_read(base, WB_SIO_REG_CHIP_MSB) << 8;
+       chip |= winbond_sio_reg_read(base, WB_SIO_REG_CHIP_LSB);
+
+       pr_notice("chip ID at %lx is %.4x\n", base, chip);
+
+       if ((chip & WB_SIO_CHIP_ID_W83627UHG_MASK) !=
+           WB_SIO_CHIP_ID_W83627UHG) {
+               pr_err("not an our chip\n");
+               ret = -ENODEV;
+       }
+
+       winbond_sio_leave(base);
+
+       return ret;
+}
+
+static int winbond_gpio_imatch(struct device *dev, unsigned int id)
+{
+       unsigned long gpios_rem;
+       int ret;
+
+       gpios_rem = params.gpios & ~GENMASK(ARRAY_SIZE(winbond_gpio_infos) - 1,
+                                           0);
+       if (gpios_rem) {
+               pr_warn("unknown ports (%lx) enabled in GPIO ports bitmask\n",
+                       gpios_rem);
+               params.gpios &= ~gpios_rem;
+       }
+
+       if (params.ppgpios & params.odgpios) {
+               pr_err("some GPIO ports are set both to push-pull and open drain mode at the same time\n");
+               return 0;
+       }
+
+       if (params.base != 0)
+               return winbond_gpio_check_chip(params.base) == 0;
+
+       /*
+        * if the 'base' module parameter is unset probe two chip default
+        * I/O port bases
+        */
+       params.base = WB_SIO_BASE;
+       ret = winbond_gpio_check_chip(params.base);
+       if (ret == 0)
+               return 1;
+       if (ret != -ENODEV && ret != -EBUSY)
+               return 0;
+
+       params.base = WB_SIO_BASE_HIGH;
+       return winbond_gpio_check_chip(params.base) == 0;
+}
+
+static int winbond_gpio_iprobe(struct device *dev, unsigned int id)
+{
+       int ret;
+
+       if (params.base == 0)
+               return -EINVAL;
+
+       ret = winbond_sio_enter(params.base);
+       if (ret)
+               return ret;
+
+       ret = winbond_gpio_configure(params.base);
+
+       winbond_sio_leave(params.base);
+
+       if (ret)
+               return ret;
+
+       /*
+        * Add 8 gpios for every GPIO port that was enabled in gpios
+        * module parameter (that wasn't disabled earlier in
+        * winbond_gpio_configure() & co. due to, for example, a pin conflict).
+        */
+       winbond_gpio_chip.ngpio = hweight_long(params.gpios) * 8;
+
+       /*
+        * GPIO6 port has only 5 pins, so if it is enabled we have to adjust
+        * the total count appropriately
+        */
+       if (params.gpios & BIT(5))
+               winbond_gpio_chip.ngpio -= (8 - 5);
+
+       winbond_gpio_chip.parent = dev;
+
+       return devm_gpiochip_add_data(dev, &winbond_gpio_chip, ¶ms.base);
+}
+
+static struct isa_driver winbond_gpio_idriver = {
+       .driver = {
+               .name   = WB_GPIO_DRIVER_NAME,
+       },
+       .match  = winbond_gpio_imatch,
+       .probe  = winbond_gpio_iprobe,
+};
+
+module_isa_driver(winbond_gpio_idriver, 1);
+
+module_param_named(base, params.base, ulong, 0444);
+MODULE_PARM_DESC(base,
+                "I/O port base (when unset - probe chip default ones)");
+
+/* This parameter sets which GPIO devices (ports) we enable */
+module_param_named(gpios, params.gpios, ulong, 0444);
+MODULE_PARM_DESC(gpios,
+                "bitmask of GPIO ports to enable (bit 0 - GPIO1, bit 1 - GPIO2, etc.");
+
+/*
+ * These two parameters below set how we configure GPIO ports output drivers.
+ * It can't be a one bitmask since we need three values per port: push-pull,
+ * open-drain and keep as-is (this is the default).
+ */
+module_param_named(ppgpios, params.ppgpios, ulong, 0444);
+MODULE_PARM_DESC(ppgpios,
+                "bitmask of GPIO ports to set to push-pull mode (bit 0 - GPIO1, bit 1 - GPIO2, etc.");
+
+module_param_named(odgpios, params.odgpios, ulong, 0444);
+MODULE_PARM_DESC(odgpios,
+                "bitmask of GPIO ports to set to open drain mode (bit 0 - GPIO1, bit 1 - GPIO2, etc.");
+
+/*
+ * GPIO2.0 and GPIO2.1 control a basic PC functionality that we
+ * don't allow tinkering with by default (it is very likely that the
+ * firmware owns these pins).
+ * These two parameters below allow overriding these prohibitions.
+ */
+module_param_named(pledgpio, params.pledgpio, bool, 0644);
+MODULE_PARM_DESC(pledgpio,
+                "enable changing value of GPIO2.0 bit (Power LED), default no.");
+
+module_param_named(beepgpio, params.beepgpio, bool, 0644);
+MODULE_PARM_DESC(beepgpio,
+                "enable changing value of GPIO2.1 bit (BEEP), default no.");
+
+MODULE_AUTHOR("Maciej S. Szmigiero <mail@maciej.szmigiero.name>");
+MODULE_DESCRIPTION("GPIO interface for Winbond Super I/O chips");
+MODULE_LICENSE("GPL");