gpio: nomadik: extract GPIO platform driver from drivers/pinctrl/nomadik/

Previously, drivers/pinctrl/nomadik/pinctrl-nomadik.c registered two
platform drivers: pinctrl & GPIO. Move the GPIO aspect to the
drivers/gpio/ folder, as would be expected.

Both drivers are intertwined for a reason; pinctrl requires access to
GPIO registers for pinmuxing, pull-disable, disabling interrupts while
setting the muxing and wakeup control. Information sharing is done
through a shared array containing GPIO chips and a few helper
functions. That shared array is not touched from gpio-nomadik when
CONFIG_PINCTRL_NOMADIK is not defined.

Make no change to the code that moved into gpio-nomadik; there should be
no behavior change following. A few functions are shared and header
comments are added. Checkpatch warnings are addressed. NUM_BANKS is
renamed to NMK_MAX_BANKS.

It is supported to compile gpio-nomadik without pinctrl-nomadik. The
opposite is not true.

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Link: https://lore.kernel.org/r/20240228-mbly-gpio-v2-6-3ba757474006@bootlin.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 660 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-nomadik.c b/drivers/gpio/gpio-nomadik.c
new file mode 100644
index 000000000000..e39477e1a58f
--- /dev/null
+++ b/drivers/gpio/gpio-nomadik.c
@@ -0,0 +1,660 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * GPIO driver for the IP block found in the Nomadik SoC; it is an AMBA device,
+ * managing 32 pins with alternate functions. It can also handle the STA2X11
+ * block from ST.
+ *
+ * The GPIO chips are shared with pinctrl-nomadik if used; it needs access for
+ * pinmuxing functionality and others.
+ *
+ * Copyright (C) 2008,2009 STMicroelectronics
+ * Copyright (C) 2009 Alessandro Rubini <rubini@unipv.it>
+ *   Rewritten based on work by Prafulla WADASKAR <prafulla.wadaskar@st.com>
+ * Copyright (C) 2011-2013 Linus Walleij <linus.walleij@linaro.org>
+ */
+#include <linux/cleanup.h>
+#include <linux/clk.h>
+#include <linux/gpio/driver.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/seq_file.h>
+#include <linux/types.h>
+
+#include <linux/gpio/gpio-nomadik.h>
+
+#ifndef CONFIG_PINCTRL_NOMADIK
+static DEFINE_SPINLOCK(nmk_gpio_slpm_lock);
+#endif
+
+void __nmk_gpio_set_slpm(struct nmk_gpio_chip *nmk_chip, unsigned int offset,
+			 enum nmk_gpio_slpm mode)
+{
+	u32 slpm;
+
+	slpm = readl(nmk_chip->addr + NMK_GPIO_SLPC);
+	if (mode == NMK_GPIO_SLPM_NOCHANGE)
+		slpm |= BIT(offset);
+	else
+		slpm &= ~BIT(offset);
+	writel(slpm, nmk_chip->addr + NMK_GPIO_SLPC);
+}
+
+static void __nmk_gpio_set_output(struct nmk_gpio_chip *nmk_chip,
+				  unsigned int offset, int val)
+{
+	if (val)
+		writel(BIT(offset), nmk_chip->addr + NMK_GPIO_DATS);
+	else
+		writel(BIT(offset), nmk_chip->addr + NMK_GPIO_DATC);
+}
+
+void __nmk_gpio_make_output(struct nmk_gpio_chip *nmk_chip,
+			    unsigned int offset, int val)
+{
+	writel(BIT(offset), nmk_chip->addr + NMK_GPIO_DIRS);
+	__nmk_gpio_set_output(nmk_chip, offset, val);
+}
+
+/* IRQ functions */
+
+static void nmk_gpio_irq_ack(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct nmk_gpio_chip *nmk_chip = gpiochip_get_data(gc);
+
+	clk_enable(nmk_chip->clk);
+	writel(BIT(d->hwirq), nmk_chip->addr + NMK_GPIO_IC);
+	clk_disable(nmk_chip->clk);
+}
+
+enum nmk_gpio_irq_type {
+	NORMAL,
+	WAKE,
+};
+
+static void __nmk_gpio_irq_modify(struct nmk_gpio_chip *nmk_chip,
+				  int offset, enum nmk_gpio_irq_type which,
+				  bool enable)
+{
+	u32 *rimscval;
+	u32 *fimscval;
+	u32 rimscreg;
+	u32 fimscreg;
+
+	if (which == NORMAL) {
+		rimscreg = NMK_GPIO_RIMSC;
+		fimscreg = NMK_GPIO_FIMSC;
+		rimscval = &nmk_chip->rimsc;
+		fimscval = &nmk_chip->fimsc;
+	} else  {
+		rimscreg = NMK_GPIO_RWIMSC;
+		fimscreg = NMK_GPIO_FWIMSC;
+		rimscval = &nmk_chip->rwimsc;
+		fimscval = &nmk_chip->fwimsc;
+	}
+
+	/* we must individually set/clear the two edges */
+	if (nmk_chip->edge_rising & BIT(offset)) {
+		if (enable)
+			*rimscval |= BIT(offset);
+		else
+			*rimscval &= ~BIT(offset);
+		writel(*rimscval, nmk_chip->addr + rimscreg);
+	}
+	if (nmk_chip->edge_falling & BIT(offset)) {
+		if (enable)
+			*fimscval |= BIT(offset);
+		else
+			*fimscval &= ~BIT(offset);
+		writel(*fimscval, nmk_chip->addr + fimscreg);
+	}
+}
+
+static void __nmk_gpio_set_wake(struct nmk_gpio_chip *nmk_chip,
+				int offset, bool on)
+{
+	/*
+	 * Ensure WAKEUP_ENABLE is on.  No need to disable it if wakeup is
+	 * disabled, since setting SLPM to 1 increases power consumption, and
+	 * wakeup is anyhow controlled by the RIMSC and FIMSC registers.
+	 */
+	if (nmk_chip->sleepmode && on) {
+		__nmk_gpio_set_slpm(nmk_chip, offset,
+				    NMK_GPIO_SLPM_WAKEUP_ENABLE);
+	}
+
+	__nmk_gpio_irq_modify(nmk_chip, offset, WAKE, on);
+}
+
+static void nmk_gpio_irq_maskunmask(struct nmk_gpio_chip *nmk_chip,
+				    struct irq_data *d, bool enable)
+{
+	unsigned long flags;
+
+	clk_enable(nmk_chip->clk);
+	spin_lock_irqsave(&nmk_gpio_slpm_lock, flags);
+	spin_lock(&nmk_chip->lock);
+
+	__nmk_gpio_irq_modify(nmk_chip, d->hwirq, NORMAL, enable);
+
+	if (!(nmk_chip->real_wake & BIT(d->hwirq)))
+		__nmk_gpio_set_wake(nmk_chip, d->hwirq, enable);
+
+	spin_unlock(&nmk_chip->lock);
+	spin_unlock_irqrestore(&nmk_gpio_slpm_lock, flags);
+	clk_disable(nmk_chip->clk);
+}
+
+static void nmk_gpio_irq_mask(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct nmk_gpio_chip *nmk_chip = gpiochip_get_data(gc);
+
+	nmk_gpio_irq_maskunmask(nmk_chip, d, false);
+	gpiochip_disable_irq(gc, irqd_to_hwirq(d));
+}
+
+static void nmk_gpio_irq_unmask(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct nmk_gpio_chip *nmk_chip = gpiochip_get_data(gc);
+
+	gpiochip_enable_irq(gc, irqd_to_hwirq(d));
+	nmk_gpio_irq_maskunmask(nmk_chip, d, true);
+}
+
+static int nmk_gpio_irq_set_wake(struct irq_data *d, unsigned int on)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct nmk_gpio_chip *nmk_chip = gpiochip_get_data(gc);
+	unsigned long flags;
+
+	clk_enable(nmk_chip->clk);
+	spin_lock_irqsave(&nmk_gpio_slpm_lock, flags);
+	spin_lock(&nmk_chip->lock);
+
+	if (irqd_irq_disabled(d))
+		__nmk_gpio_set_wake(nmk_chip, d->hwirq, on);
+
+	if (on)
+		nmk_chip->real_wake |= BIT(d->hwirq);
+	else
+		nmk_chip->real_wake &= ~BIT(d->hwirq);
+
+	spin_unlock(&nmk_chip->lock);
+	spin_unlock_irqrestore(&nmk_gpio_slpm_lock, flags);
+	clk_disable(nmk_chip->clk);
+
+	return 0;
+}
+
+static int nmk_gpio_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct nmk_gpio_chip *nmk_chip = gpiochip_get_data(gc);
+	bool enabled = !irqd_irq_disabled(d);
+	bool wake = irqd_is_wakeup_set(d);
+	unsigned long flags;
+
+	if (type & IRQ_TYPE_LEVEL_HIGH)
+		return -EINVAL;
+	if (type & IRQ_TYPE_LEVEL_LOW)
+		return -EINVAL;
+
+	clk_enable(nmk_chip->clk);
+	spin_lock_irqsave(&nmk_chip->lock, flags);
+
+	if (enabled)
+		__nmk_gpio_irq_modify(nmk_chip, d->hwirq, NORMAL, false);
+
+	if (enabled || wake)
+		__nmk_gpio_irq_modify(nmk_chip, d->hwirq, WAKE, false);
+
+	nmk_chip->edge_rising &= ~BIT(d->hwirq);
+	if (type & IRQ_TYPE_EDGE_RISING)
+		nmk_chip->edge_rising |= BIT(d->hwirq);
+
+	nmk_chip->edge_falling &= ~BIT(d->hwirq);
+	if (type & IRQ_TYPE_EDGE_FALLING)
+		nmk_chip->edge_falling |= BIT(d->hwirq);
+
+	if (enabled)
+		__nmk_gpio_irq_modify(nmk_chip, d->hwirq, NORMAL, true);
+
+	if (enabled || wake)
+		__nmk_gpio_irq_modify(nmk_chip, d->hwirq, WAKE, true);
+
+	spin_unlock_irqrestore(&nmk_chip->lock, flags);
+	clk_disable(nmk_chip->clk);
+
+	return 0;
+}
+
+static unsigned int nmk_gpio_irq_startup(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct nmk_gpio_chip *nmk_chip = gpiochip_get_data(gc);
+
+	clk_enable(nmk_chip->clk);
+	nmk_gpio_irq_unmask(d);
+	return 0;
+}
+
+static void nmk_gpio_irq_shutdown(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct nmk_gpio_chip *nmk_chip = gpiochip_get_data(gc);
+
+	nmk_gpio_irq_mask(d);
+	clk_disable(nmk_chip->clk);
+}
+
+static void nmk_gpio_irq_handler(struct irq_desc *desc)
+{
+	struct irq_chip *host_chip = irq_desc_get_chip(desc);
+	struct gpio_chip *chip = irq_desc_get_handler_data(desc);
+	struct nmk_gpio_chip *nmk_chip = gpiochip_get_data(chip);
+	u32 status;
+
+	chained_irq_enter(host_chip, desc);
+
+	clk_enable(nmk_chip->clk);
+	status = readl(nmk_chip->addr + NMK_GPIO_IS);
+	clk_disable(nmk_chip->clk);
+
+	while (status) {
+		int bit = __ffs(status);
+
+		generic_handle_domain_irq(chip->irq.domain, bit);
+		status &= ~BIT(bit);
+	}
+
+	chained_irq_exit(host_chip, desc);
+}
+
+/* I/O Functions */
+
+static int nmk_gpio_get_dir(struct gpio_chip *chip, unsigned int offset)
+{
+	struct nmk_gpio_chip *nmk_chip = gpiochip_get_data(chip);
+	int dir;
+
+	clk_enable(nmk_chip->clk);
+
+	dir = readl(nmk_chip->addr + NMK_GPIO_DIR) & BIT(offset);
+
+	clk_disable(nmk_chip->clk);
+
+	if (dir)
+		return GPIO_LINE_DIRECTION_OUT;
+
+	return GPIO_LINE_DIRECTION_IN;
+}
+
+static int nmk_gpio_make_input(struct gpio_chip *chip, unsigned int offset)
+{
+	struct nmk_gpio_chip *nmk_chip = gpiochip_get_data(chip);
+
+	clk_enable(nmk_chip->clk);
+
+	writel(BIT(offset), nmk_chip->addr + NMK_GPIO_DIRC);
+
+	clk_disable(nmk_chip->clk);
+
+	return 0;
+}
+
+static int nmk_gpio_get_input(struct gpio_chip *chip, unsigned int offset)
+{
+	struct nmk_gpio_chip *nmk_chip = gpiochip_get_data(chip);
+	int value;
+
+	clk_enable(nmk_chip->clk);
+
+	value = !!(readl(nmk_chip->addr + NMK_GPIO_DAT) & BIT(offset));
+
+	clk_disable(nmk_chip->clk);
+
+	return value;
+}
+
+static void nmk_gpio_set_output(struct gpio_chip *chip, unsigned int offset,
+				int val)
+{
+	struct nmk_gpio_chip *nmk_chip = gpiochip_get_data(chip);
+
+	clk_enable(nmk_chip->clk);
+
+	__nmk_gpio_set_output(nmk_chip, offset, val);
+
+	clk_disable(nmk_chip->clk);
+}
+
+static int nmk_gpio_make_output(struct gpio_chip *chip, unsigned int offset,
+				int val)
+{
+	struct nmk_gpio_chip *nmk_chip = gpiochip_get_data(chip);
+
+	clk_enable(nmk_chip->clk);
+
+	__nmk_gpio_make_output(nmk_chip, offset, val);
+
+	clk_disable(nmk_chip->clk);
+
+	return 0;
+}
+
+#ifdef CONFIG_DEBUG_FS
+
+static int nmk_gpio_get_mode(struct nmk_gpio_chip *nmk_chip, int offset)
+{
+	u32 afunc, bfunc;
+
+	clk_enable(nmk_chip->clk);
+
+	afunc = readl(nmk_chip->addr + NMK_GPIO_AFSLA) & BIT(offset);
+	bfunc = readl(nmk_chip->addr + NMK_GPIO_AFSLB) & BIT(offset);
+
+	clk_disable(nmk_chip->clk);
+
+	return (afunc ? NMK_GPIO_ALT_A : 0) | (bfunc ? NMK_GPIO_ALT_B : 0);
+}
+
+void nmk_gpio_dbg_show_one(struct seq_file *s, struct pinctrl_dev *pctldev,
+			   struct gpio_chip *chip, unsigned int offset,
+			   unsigned int gpio)
+{
+	struct nmk_gpio_chip *nmk_chip = gpiochip_get_data(chip);
+	int mode;
+	bool is_out;
+	bool data_out;
+	bool pull;
+	static const char * const modes[] = {
+		[NMK_GPIO_ALT_GPIO]	= "gpio",
+		[NMK_GPIO_ALT_A]	= "altA",
+		[NMK_GPIO_ALT_B]	= "altB",
+		[NMK_GPIO_ALT_C]	= "altC",
+		[NMK_GPIO_ALT_C + 1]	= "altC1",
+		[NMK_GPIO_ALT_C + 2]	= "altC2",
+		[NMK_GPIO_ALT_C + 3]	= "altC3",
+		[NMK_GPIO_ALT_C + 4]	= "altC4",
+	};
+
+	char *label = gpiochip_dup_line_label(chip, offset);
+	if (IS_ERR(label))
+		return;
+
+	clk_enable(nmk_chip->clk);
+	is_out = !!(readl(nmk_chip->addr + NMK_GPIO_DIR) & BIT(offset));
+	pull = !(readl(nmk_chip->addr + NMK_GPIO_PDIS) & BIT(offset));
+	data_out = !!(readl(nmk_chip->addr + NMK_GPIO_DAT) & BIT(offset));
+	mode = nmk_gpio_get_mode(nmk_chip, offset);
+#ifdef CONFIG_PINCTRL_NOMADIK
+	if (mode == NMK_GPIO_ALT_C && pctldev)
+		mode = nmk_prcm_gpiocr_get_mode(pctldev, gpio);
+#endif
+
+	if (is_out) {
+		seq_printf(s, " gpio-%-3d (%-20.20s) out %s           %s",
+			   gpio,
+			   label ?: "(none)",
+			   data_out ? "hi" : "lo",
+			   (mode < 0) ? "unknown" : modes[mode]);
+	} else {
+		int irq = chip->to_irq(chip, offset);
+		const int pullidx = pull ? 1 : 0;
+		int val;
+		static const char * const pulls[] = {
+			"none        ",
+			"pull enabled",
+		};
+
+		seq_printf(s, " gpio-%-3d (%-20.20s) in  %s %s",
+			   gpio,
+			   label ?: "(none)",
+			   pulls[pullidx],
+			   (mode < 0) ? "unknown" : modes[mode]);
+
+		val = nmk_gpio_get_input(chip, offset);
+		seq_printf(s, " VAL %d", val);
+
+		/*
+		 * This races with request_irq(), set_irq_type(),
+		 * and set_irq_wake() ... but those are "rare".
+		 */
+		if (irq > 0 && irq_has_action(irq)) {
+			char *trigger;
+			bool wake;
+
+			if (nmk_chip->edge_rising & BIT(offset))
+				trigger = "edge-rising";
+			else if (nmk_chip->edge_falling & BIT(offset))
+				trigger = "edge-falling";
+			else
+				trigger = "edge-undefined";
+
+			wake = !!(nmk_chip->real_wake & BIT(offset));
+
+			seq_printf(s, " irq-%d %s%s",
+				   irq, trigger, wake ? " wakeup" : "");
+		}
+	}
+	clk_disable(nmk_chip->clk);
+}
+
+static void nmk_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
+{
+	unsigned int i, gpio = chip->base;
+
+	for (i = 0; i < chip->ngpio; i++, gpio++) {
+		nmk_gpio_dbg_show_one(s, NULL, chip, i, gpio);
+		seq_puts(s, "\n");
+	}
+}
+
+#else
+
+static inline void nmk_gpio_dbg_show_one(struct seq_file *s,
+					 struct pinctrl_dev *pctldev,
+					 struct gpio_chip *chip,
+					 unsigned int offset,
+					 unsigned int gpio)
+{
+}
+
+#define nmk_gpio_dbg_show	NULL
+
+#endif
+
+/*
+ * We will allocate memory for the state container using devm* allocators
+ * binding to the first device reaching this point, it doesn't matter if
+ * it is the pin controller or GPIO driver. However we need to use the right
+ * platform device when looking up resources so pay attention to pdev.
+ */
+struct nmk_gpio_chip *nmk_gpio_populate_chip(struct device_node *np,
+					     struct platform_device *pdev)
+{
+	struct nmk_gpio_chip *nmk_chip;
+	struct platform_device *gpio_pdev;
+	struct gpio_chip *chip;
+	struct resource *res;
+	struct clk *clk;
+	void __iomem *base;
+	u32 id;
+
+	gpio_pdev = of_find_device_by_node(np);
+	if (!gpio_pdev) {
+		pr_err("populate \"%pOFn\": device not found\n", np);
+		return ERR_PTR(-ENODEV);
+	}
+	if (of_property_read_u32(np, "gpio-bank", &id)) {
+		dev_err(&pdev->dev, "populate: gpio-bank property not found\n");
+		platform_device_put(gpio_pdev);
+		return ERR_PTR(-EINVAL);
+	}
+
+#ifdef CONFIG_PINCTRL_NOMADIK
+	/* Already populated? */
+	nmk_chip = nmk_gpio_chips[id];
+	if (nmk_chip) {
+		platform_device_put(gpio_pdev);
+		return nmk_chip;
+	}
+#endif
+
+	nmk_chip = devm_kzalloc(&pdev->dev, sizeof(*nmk_chip), GFP_KERNEL);
+	if (!nmk_chip) {
+		platform_device_put(gpio_pdev);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	nmk_chip->bank = id;
+	chip = &nmk_chip->chip;
+	chip->base = id * NMK_GPIO_PER_CHIP;
+	chip->ngpio = NMK_GPIO_PER_CHIP;
+	chip->label = dev_name(&gpio_pdev->dev);
+	chip->parent = &gpio_pdev->dev;
+
+	res = platform_get_resource(gpio_pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base)) {
+		platform_device_put(gpio_pdev);
+		return ERR_CAST(base);
+	}
+	nmk_chip->addr = base;
+
+	clk = clk_get(&gpio_pdev->dev, NULL);
+	if (IS_ERR(clk)) {
+		platform_device_put(gpio_pdev);
+		return (void *)clk;
+	}
+	clk_prepare(clk);
+	nmk_chip->clk = clk;
+
+#ifdef CONFIG_PINCTRL_NOMADIK
+	BUG_ON(nmk_chip->bank >= ARRAY_SIZE(nmk_gpio_chips));
+	nmk_gpio_chips[id] = nmk_chip;
+#endif
+	return nmk_chip;
+}
+
+static void nmk_gpio_irq_print_chip(struct irq_data *d, struct seq_file *p)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct nmk_gpio_chip *nmk_chip = gpiochip_get_data(gc);
+
+	seq_printf(p, "nmk%u-%u-%u", nmk_chip->bank,
+		   gc->base, gc->base + gc->ngpio - 1);
+}
+
+static const struct irq_chip nmk_irq_chip = {
+	.irq_ack = nmk_gpio_irq_ack,
+	.irq_mask = nmk_gpio_irq_mask,
+	.irq_unmask = nmk_gpio_irq_unmask,
+	.irq_set_type = nmk_gpio_irq_set_type,
+	.irq_set_wake = nmk_gpio_irq_set_wake,
+	.irq_startup = nmk_gpio_irq_startup,
+	.irq_shutdown = nmk_gpio_irq_shutdown,
+	.irq_print_chip = nmk_gpio_irq_print_chip,
+	.flags = IRQCHIP_MASK_ON_SUSPEND | IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
+static int nmk_gpio_probe(struct platform_device *dev)
+{
+	struct device_node *np = dev->dev.of_node;
+	struct nmk_gpio_chip *nmk_chip;
+	struct gpio_chip *chip;
+	struct gpio_irq_chip *girq;
+	bool supports_sleepmode;
+	int irq;
+	int ret;
+
+	nmk_chip = nmk_gpio_populate_chip(np, dev);
+	if (IS_ERR(nmk_chip)) {
+		dev_err(&dev->dev, "could not populate nmk chip struct\n");
+		return PTR_ERR(nmk_chip);
+	}
+
+	supports_sleepmode =
+		of_property_read_bool(np, "st,supports-sleepmode");
+
+	/* Correct platform device ID */
+	dev->id = nmk_chip->bank;
+
+	irq = platform_get_irq(dev, 0);
+	if (irq < 0)
+		return irq;
+
+	/*
+	 * The virt address in nmk_chip->addr is in the nomadik register space,
+	 * so we can simply convert the resource address, without remapping
+	 */
+	nmk_chip->sleepmode = supports_sleepmode;
+	spin_lock_init(&nmk_chip->lock);
+
+	chip = &nmk_chip->chip;
+	chip->parent = &dev->dev;
+	chip->request = gpiochip_generic_request;
+	chip->free = gpiochip_generic_free;
+	chip->get_direction = nmk_gpio_get_dir;
+	chip->direction_input = nmk_gpio_make_input;
+	chip->get = nmk_gpio_get_input;
+	chip->direction_output = nmk_gpio_make_output;
+	chip->set = nmk_gpio_set_output;
+	chip->dbg_show = nmk_gpio_dbg_show;
+	chip->can_sleep = false;
+	chip->owner = THIS_MODULE;
+
+	girq = &chip->irq;
+	gpio_irq_chip_set_chip(girq, &nmk_irq_chip);
+	girq->parent_handler = nmk_gpio_irq_handler;
+	girq->num_parents = 1;
+	girq->parents = devm_kcalloc(&dev->dev, 1,
+				     sizeof(*girq->parents),
+				     GFP_KERNEL);
+	if (!girq->parents)
+		return -ENOMEM;
+	girq->parents[0] = irq;
+	girq->default_type = IRQ_TYPE_NONE;
+	girq->handler = handle_edge_irq;
+
+	clk_enable(nmk_chip->clk);
+	nmk_chip->lowemi = readl_relaxed(nmk_chip->addr + NMK_GPIO_LOWEMI);
+	clk_disable(nmk_chip->clk);
+
+	ret = gpiochip_add_data(chip, nmk_chip);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(dev, nmk_chip);
+
+	dev_info(&dev->dev, "chip registered\n");
+
+	return 0;
+}
+
+static const struct of_device_id nmk_gpio_match[] = {
+	{ .compatible = "st,nomadik-gpio", },
+	{}
+};
+
+static struct platform_driver nmk_gpio_driver = {
+	.driver = {
+		.name = "gpio",
+		.of_match_table = nmk_gpio_match,
+	},
+	.probe = nmk_gpio_probe,
+};
+
+static int __init nmk_gpio_init(void)
+{
+	return platform_driver_register(&nmk_gpio_driver);
+}
+subsys_initcall(nmk_gpio_init);