1 files changed, 463 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-grgpio.c b/drivers/gpio/gpio-grgpio.c
new file mode 100644
index 000000000..e4fa84e22
--- /dev/null
+++ b/drivers/gpio/gpio-grgpio.c
@@ -0,0 +1,463 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for Aeroflex Gaisler GRGPIO General Purpose I/O cores.
+ *
+ * 2013 (c) Aeroflex Gaisler AB
+ *
+ * This driver supports the GRGPIO GPIO core available in the GRLIB VHDL
+ * IP core library.
+ *
+ * Full documentation of the GRGPIO core can be found here:
+ * http://www.gaisler.com/products/grlib/grip.pdf
+ *
+ * See "Documentation/devicetree/bindings/gpio/gpio-grgpio.txt" for
+ * information on open firmware properties.
+ *
+ * Contributors: Andreas Larsson <andreas@gaisler.com>
+ */
+
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/gpio/driver.h>
+#include <linux/gpio/generic.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/string_choices.h>
+
+#define GRGPIO_MAX_NGPIO 32
+
+#define GRGPIO_DATA		0x00
+#define GRGPIO_OUTPUT		0x04
+#define GRGPIO_DIR		0x08
+#define GRGPIO_IMASK		0x0c
+#define GRGPIO_IPOL		0x10
+#define GRGPIO_IEDGE		0x14
+#define GRGPIO_BYPASS		0x18
+#define GRGPIO_IMAP_BASE	0x20
+
+/* Structure for an irq of the core - called an underlying irq */
+struct grgpio_uirq {
+	atomic_t refcnt; /* Reference counter to manage requesting/freeing of uirq */
+	u8 uirq; /* Underlying irq of the gpio driver */
+};
+
+/*
+ * Structure for an irq of a gpio line handed out by this driver. The index is
+ * used to map to the corresponding underlying irq.
+ */
+struct grgpio_lirq {
+	s8 index; /* Index into struct grgpio_priv's uirqs, or -1 */
+	u8 irq; /* irq for the gpio line */
+};
+
+struct grgpio_priv {
+	struct gpio_generic_chip chip;
+	void __iomem *regs;
+	struct device *dev;
+
+	u32 imask; /* irq mask shadow register */
+
+	/*
+	 * The grgpio core can have multiple "underlying" irqs. The gpio lines
+	 * can be mapped to any one or none of these underlying irqs
+	 * independently of each other. This driver sets up an irq domain and
+	 * hands out separate irqs to each gpio line
+	 */
+	struct irq_domain *domain;
+
+	/*
+	 * This array contains information on each underlying irq, each
+	 * irq of the grgpio core itself.
+	 */
+	struct grgpio_uirq uirqs[GRGPIO_MAX_NGPIO];
+
+	/*
+	 * This array contains information for each gpio line on the irqs
+	 * obtains from this driver. An index value of -1 for a certain gpio
+	 * line indicates that the line has no irq. Otherwise the index connects
+	 * the irq to the underlying irq by pointing into the uirqs array.
+	 */
+	struct grgpio_lirq lirqs[GRGPIO_MAX_NGPIO];
+};
+
+static void grgpio_set_imask(struct grgpio_priv *priv, unsigned int offset,
+			     int val)
+{
+	if (val)
+		priv->imask |= BIT(offset);
+	else
+		priv->imask &= ~BIT(offset);
+
+	gpio_generic_write_reg(&priv->chip, priv->regs + GRGPIO_IMASK, priv->imask);
+}
+
+static int grgpio_to_irq(struct gpio_chip *gc, unsigned offset)
+{
+	struct grgpio_priv *priv = gpiochip_get_data(gc);
+
+	if (offset >= gc->ngpio)
+		return -ENXIO;
+
+	if (priv->lirqs[offset].index < 0)
+		return -ENXIO;
+
+	return irq_create_mapping(priv->domain, offset);
+}
+
+/* -------------------- IRQ chip functions -------------------- */
+
+static int grgpio_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	struct grgpio_priv *priv = irq_data_get_irq_chip_data(d);
+	u32 mask = BIT(d->hwirq);
+	u32 ipol;
+	u32 iedge;
+	u32 pol;
+	u32 edge;
+
+	switch (type) {
+	case IRQ_TYPE_LEVEL_LOW:
+		pol = 0;
+		edge = 0;
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		pol = mask;
+		edge = 0;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		pol = 0;
+		edge = mask;
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		pol = mask;
+		edge = mask;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	guard(gpio_generic_lock_irqsave)(&priv->chip);
+
+	ipol = gpio_generic_read_reg(&priv->chip, priv->regs + GRGPIO_IPOL) & ~mask;
+	iedge = gpio_generic_read_reg(&priv->chip, priv->regs + GRGPIO_IEDGE) & ~mask;
+
+	gpio_generic_write_reg(&priv->chip, priv->regs + GRGPIO_IPOL, ipol | pol);
+	gpio_generic_write_reg(&priv->chip, priv->regs + GRGPIO_IEDGE, iedge | edge);
+
+	return 0;
+}
+
+static void grgpio_irq_mask(struct irq_data *d)
+{
+	struct grgpio_priv *priv = irq_data_get_irq_chip_data(d);
+	int offset = d->hwirq;
+
+	scoped_guard(gpio_generic_lock_irqsave, &priv->chip)
+		grgpio_set_imask(priv, offset, 0);
+
+	gpiochip_disable_irq(&priv->chip.gc, d->hwirq);
+}
+
+static void grgpio_irq_unmask(struct irq_data *d)
+{
+	struct grgpio_priv *priv = irq_data_get_irq_chip_data(d);
+	int offset = d->hwirq;
+
+	gpiochip_enable_irq(&priv->chip.gc, d->hwirq);
+
+	guard(gpio_generic_lock_irqsave)(&priv->chip);
+
+	grgpio_set_imask(priv, offset, 1);
+}
+
+static const struct irq_chip grgpio_irq_chip = {
+	.name			= "grgpio",
+	.irq_mask		= grgpio_irq_mask,
+	.irq_unmask		= grgpio_irq_unmask,
+	.irq_set_type		= grgpio_irq_set_type,
+	.flags = IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
+static irqreturn_t grgpio_irq_handler(int irq, void *dev)
+{
+	struct grgpio_priv *priv = dev;
+	int ngpio = priv->chip.gc.ngpio;
+	int i;
+	int match = 0;
+
+	guard(gpio_generic_lock_irqsave)(&priv->chip);
+
+	/*
+	 * For each gpio line, call its interrupt handler if it its underlying
+	 * irq matches the current irq that is handled.
+	 */
+	for (i = 0; i < ngpio; i++) {
+		struct grgpio_lirq *lirq = &priv->lirqs[i];
+
+		if (priv->imask & BIT(i) && lirq->index >= 0 &&
+		    priv->uirqs[lirq->index].uirq == irq) {
+			generic_handle_irq(lirq->irq);
+			match = 1;
+		}
+	}
+
+	if (!match)
+		dev_warn(priv->dev, "No gpio line matched irq %d\n", irq);
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * This function will be called as a consequence of the call to
+ * irq_create_mapping in grgpio_to_irq
+ */
+static int grgpio_irq_map(struct irq_domain *d, unsigned int irq,
+			  irq_hw_number_t hwirq)
+{
+	struct grgpio_priv *priv = d->host_data;
+	struct grgpio_lirq *lirq;
+	struct grgpio_uirq *uirq;
+	unsigned long flags;
+	int offset = hwirq;
+	int ret = 0;
+
+	if (!priv)
+		return -EINVAL;
+
+	lirq = &priv->lirqs[offset];
+	if (lirq->index < 0)
+		return -EINVAL;
+
+	dev_dbg(priv->dev, "Mapping irq %d for gpio line %d\n",
+		irq, offset);
+
+	gpio_generic_chip_lock_irqsave(&priv->chip, flags);
+	lirq->irq = irq;
+	uirq = &priv->uirqs[lirq->index];
+	gpio_generic_chip_unlock_irqrestore(&priv->chip, flags);
+
+	/* Request underlying irq if not already requested */
+	if (atomic_fetch_add(1, &uirq->refcnt) == 0) {
+		ret = request_irq(uirq->uirq, grgpio_irq_handler, 0,
+				  dev_name(priv->dev), priv);
+		if (ret) {
+			dev_err(priv->dev,
+				"Could not request underlying irq %d\n",
+				uirq->uirq);
+			atomic_dec(&uirq->refcnt); /* rollback */
+			return ret;
+		}
+	}
+
+	/* Setup irq  */
+	irq_set_chip_data(irq, priv);
+	irq_set_chip_and_handler(irq, &grgpio_irq_chip,
+				 handle_simple_irq);
+	irq_set_noprobe(irq);
+
+	return ret;
+}
+
+static void grgpio_irq_unmap(struct irq_domain *d, unsigned int irq)
+{
+	struct grgpio_priv *priv = d->host_data;
+	int index;
+	struct grgpio_lirq *lirq;
+	struct grgpio_uirq *uirq;
+	unsigned long flags;
+	int ngpio = priv->chip.gc.ngpio;
+	int i;
+
+	irq_set_chip_and_handler(irq, NULL, NULL);
+	irq_set_chip_data(irq, NULL);
+
+	gpio_generic_chip_lock_irqsave(&priv->chip, flags);
+
+	/* Free underlying irq if last user unmapped */
+	index = -1;
+	for (i = 0; i < ngpio; i++) {
+		lirq = &priv->lirqs[i];
+		if (lirq->irq == irq) {
+			grgpio_set_imask(priv, i, 0);
+			lirq->irq = 0;
+			index = lirq->index;
+			break;
+		}
+	}
+	WARN_ON(index < 0);
+
+	if (index >= 0) {
+		uirq = &priv->uirqs[lirq->index];
+		if (atomic_dec_and_test(&uirq->refcnt)) {
+			gpio_generic_chip_unlock_irqrestore(&priv->chip, flags);
+			free_irq(uirq->uirq, priv);
+			return;
+		}
+	}
+
+	gpio_generic_chip_unlock_irqrestore(&priv->chip, flags);
+}
+
+static void grgpio_irq_domain_remove(void *data)
+{
+	struct irq_domain *domain = data;
+
+	irq_domain_remove(domain);
+}
+
+static const struct irq_domain_ops grgpio_irq_domain_ops = {
+	.map	= grgpio_irq_map,
+	.unmap	= grgpio_irq_unmap,
+};
+
+/* ------------------------------------------------------------ */
+
+static int grgpio_probe(struct platform_device *ofdev)
+{
+	struct device_node *np = ofdev->dev.of_node;
+	struct gpio_generic_chip_config config;
+	struct device *dev = &ofdev->dev;
+	void  __iomem *regs;
+	struct gpio_chip *gc;
+	struct grgpio_priv *priv;
+	int err;
+	u32 prop;
+	s32 *irqmap;
+	int size;
+	int i;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	regs = devm_platform_ioremap_resource(ofdev, 0);
+	if (IS_ERR(regs))
+		return PTR_ERR(regs);
+
+	config = (struct gpio_generic_chip_config) {
+		.dev = dev,
+		.sz = 4,
+		.dat = regs + GRGPIO_DATA,
+		.set = regs + GRGPIO_OUTPUT,
+		.dirout = regs + GRGPIO_DIR,
+		.flags = GPIO_GENERIC_BIG_ENDIAN_BYTE_ORDER,
+	};
+
+	gc = &priv->chip.gc;
+	err = gpio_generic_chip_init(&priv->chip, &config);
+	if (err) {
+		dev_err(dev, "failed to initialize the generic GPIO chip\n");
+		return err;
+	}
+
+	priv->regs = regs;
+	priv->imask = gpio_generic_read_reg(&priv->chip, regs + GRGPIO_IMASK);
+	priv->dev = dev;
+
+	gc->owner = THIS_MODULE;
+	gc->to_irq = grgpio_to_irq;
+	gc->label = devm_kasprintf(dev, GFP_KERNEL, "%pOF", np);
+	if (!gc->label)
+		return -ENOMEM;
+
+	gc->base = -1;
+
+	err = of_property_read_u32(np, "nbits", &prop);
+	if (err || prop <= 0 || prop > GRGPIO_MAX_NGPIO) {
+		gc->ngpio = GRGPIO_MAX_NGPIO;
+		dev_dbg(dev, "No or invalid nbits property: assume %d\n",
+			gc->ngpio);
+	} else {
+		gc->ngpio = prop;
+	}
+
+	/*
+	 * The irqmap contains the index values indicating which underlying irq,
+	 * if anyone, is connected to that line
+	 */
+	irqmap = (s32 *)of_get_property(np, "irqmap", &size);
+	if (irqmap) {
+		if (size < gc->ngpio) {
+			dev_err(dev,
+				"irqmap shorter than ngpio (%d < %d)\n",
+				size, gc->ngpio);
+			return -EINVAL;
+		}
+
+		priv->domain = irq_domain_create_linear(dev_fwnode(&ofdev->dev), gc->ngpio,
+							&grgpio_irq_domain_ops, priv);
+		if (!priv->domain) {
+			dev_err(dev, "Could not add irq domain\n");
+			return -EINVAL;
+		}
+
+		err = devm_add_action_or_reset(dev, grgpio_irq_domain_remove,
+					       priv->domain);
+		if (err)
+			return err;
+
+		for (i = 0; i < gc->ngpio; i++) {
+			struct grgpio_lirq *lirq;
+			int ret;
+
+			lirq = &priv->lirqs[i];
+			lirq->index = irqmap[i];
+
+			if (lirq->index < 0)
+				continue;
+
+			ret = platform_get_irq(ofdev, lirq->index);
+			if (ret <= 0) {
+				/*
+				 * Continue without irq functionality for that
+				 * gpio line
+				 */
+				continue;
+			}
+			priv->uirqs[lirq->index].uirq = ret;
+			atomic_set(&priv->uirqs[lirq->index].refcnt, 0);
+		}
+	}
+
+	err = devm_gpiochip_add_data(dev, gc, priv);
+	if (err) {
+		dev_err(dev, "Could not add gpiochip\n");
+		return err;
+	}
+
+	dev_info(dev, "regs=0x%p, base=%d, ngpio=%d, irqs=%s\n",
+		 priv->regs, gc->base, gc->ngpio, str_on_off(priv->domain));
+
+	return 0;
+}
+
+static const struct of_device_id grgpio_match[] = {
+	{.name = "GAISLER_GPIO"},
+	{.name = "01_01a"},
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, grgpio_match);
+
+static struct platform_driver grgpio_driver = {
+	.driver = {
+		.name = "grgpio",
+		.of_match_table = grgpio_match,
+	},
+	.probe = grgpio_probe,
+};
+module_platform_driver(grgpio_driver);
+
+MODULE_AUTHOR("Aeroflex Gaisler AB.");
+MODULE_DESCRIPTION("Driver for Aeroflex Gaisler GRGPIO");
+MODULE_LICENSE("GPL");