Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 733 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-winbond.c b/drivers/gpio/gpio-winbond.c
new file mode 100644
index 000000000..4b61d975c
--- /dev/null
+++ b/drivers/gpio/gpio-winbond.c
@@ -0,0 +1,733 @@
+// 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, &params.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;
+	int ret;
+
+	winbond_gpio_get_info(&offset, &info);
+
+	ret = winbond_sio_enter(*base);
+	if (ret)
+		return ret;
+
+	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, &params.gpios, BITS_PER_LONG)
+		if (!winbond_gpio_configure_port(base, i))
+			__clear_bit(i, &params.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, &params.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");