1 files changed, 325 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-realtek-otto.c b/drivers/gpio/gpio-realtek-otto.c
new file mode 100644
index 000000000000..cb64fb5a51aa
--- /dev/null
+++ b/drivers/gpio/gpio-realtek-otto.c
@@ -0,0 +1,325 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/gpio/driver.h>
+#include <linux/irq.h>
+#include <linux/minmax.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+/*
+ * Total register block size is 0x1C for one bank of four ports (A, B, C, D).
+ * An optional second bank, with ports E, F, G, and H, may be present, starting
+ * at register offset 0x1C.
+ */
+
+/*
+ * Pin select: (0) "normal", (1) "dedicate peripheral"
+ * Not used on RTL8380/RTL8390, peripheral selection is managed by control bits
+ * in the peripheral registers.
+ */
+#define REALTEK_GPIO_REG_CNR		0x00
+/* Clear bit (0) for input, set bit (1) for output */
+#define REALTEK_GPIO_REG_DIR		0x08
+#define REALTEK_GPIO_REG_DATA		0x0C
+/* Read bit for IRQ status, write 1 to clear IRQ */
+#define REALTEK_GPIO_REG_ISR		0x10
+/* Two bits per GPIO in IMR registers */
+#define REALTEK_GPIO_REG_IMR		0x14
+#define REALTEK_GPIO_REG_IMR_AB		0x14
+#define REALTEK_GPIO_REG_IMR_CD		0x18
+#define REALTEK_GPIO_IMR_LINE_MASK	GENMASK(1, 0)
+#define REALTEK_GPIO_IRQ_EDGE_FALLING	1
+#define REALTEK_GPIO_IRQ_EDGE_RISING	2
+#define REALTEK_GPIO_IRQ_EDGE_BOTH	3
+
+#define REALTEK_GPIO_MAX		32
+#define REALTEK_GPIO_PORTS_PER_BANK	4
+
+/**
+ * realtek_gpio_ctrl - Realtek Otto GPIO driver data
+ *
+ * @gc: Associated gpio_chip instance
+ * @base: Base address of the register block for a GPIO bank
+ * @lock: Lock for accessing the IRQ registers and values
+ * @intr_mask: Mask for interrupts lines
+ * @intr_type: Interrupt type selection
+ *
+ * Because the interrupt mask register (IMR) combines the function of IRQ type
+ * selection and masking, two extra values are stored. @intr_mask is used to
+ * mask/unmask the interrupts for a GPIO port, and @intr_type is used to store
+ * the selected interrupt types. The logical AND of these values is written to
+ * IMR on changes.
+ */
+struct realtek_gpio_ctrl {
+	struct gpio_chip gc;
+	void __iomem *base;
+	raw_spinlock_t lock;
+	u16 intr_mask[REALTEK_GPIO_PORTS_PER_BANK];
+	u16 intr_type[REALTEK_GPIO_PORTS_PER_BANK];
+};
+
+/* Expand with more flags as devices with other quirks are added */
+enum realtek_gpio_flags {
+	/*
+	 * Allow disabling interrupts, for cases where the port order is
+	 * unknown. This may result in a port mismatch between ISR and IMR.
+	 * An interrupt would appear to come from a different line than the
+	 * line the IRQ handler was assigned to, causing uncaught interrupts.
+	 */
+	GPIO_INTERRUPTS_DISABLED = BIT(0),
+};
+
+static struct realtek_gpio_ctrl *irq_data_to_ctrl(struct irq_data *data)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+
+	return container_of(gc, struct realtek_gpio_ctrl, gc);
+}
+
+/*
+ * Normal port order register access
+ *
+ * Port information is stored with the first port at offset 0, followed by the
+ * second, etc. Most registers store one bit per GPIO and use a u8 value per
+ * port. The two interrupt mask registers store two bits per GPIO, so use u16
+ * values.
+ */
+static void realtek_gpio_write_imr(struct realtek_gpio_ctrl *ctrl,
+	unsigned int port, u16 irq_type, u16 irq_mask)
+{
+	iowrite16(irq_type & irq_mask, ctrl->base + REALTEK_GPIO_REG_IMR + 2 * port);
+}
+
+static void realtek_gpio_clear_isr(struct realtek_gpio_ctrl *ctrl,
+	unsigned int port, u8 mask)
+{
+	iowrite8(mask, ctrl->base + REALTEK_GPIO_REG_ISR + port);
+}
+
+static u8 realtek_gpio_read_isr(struct realtek_gpio_ctrl *ctrl, unsigned int port)
+{
+	return ioread8(ctrl->base + REALTEK_GPIO_REG_ISR + port);
+}
+
+/* Set the rising and falling edge mask bits for a GPIO port pin */
+static u16 realtek_gpio_imr_bits(unsigned int pin, u16 value)
+{
+	return (value & REALTEK_GPIO_IMR_LINE_MASK) << 2 * pin;
+}
+
+static void realtek_gpio_irq_ack(struct irq_data *data)
+{
+	struct realtek_gpio_ctrl *ctrl = irq_data_to_ctrl(data);
+	irq_hw_number_t line = irqd_to_hwirq(data);
+	unsigned int port = line / 8;
+	unsigned int port_pin = line % 8;
+
+	realtek_gpio_clear_isr(ctrl, port, BIT(port_pin));
+}
+
+static void realtek_gpio_irq_unmask(struct irq_data *data)
+{
+	struct realtek_gpio_ctrl *ctrl = irq_data_to_ctrl(data);
+	unsigned int line = irqd_to_hwirq(data);
+	unsigned int port = line / 8;
+	unsigned int port_pin = line % 8;
+	unsigned long flags;
+	u16 m;
+
+	raw_spin_lock_irqsave(&ctrl->lock, flags);
+	m = ctrl->intr_mask[port];
+	m |= realtek_gpio_imr_bits(port_pin, REALTEK_GPIO_IMR_LINE_MASK);
+	ctrl->intr_mask[port] = m;
+	realtek_gpio_write_imr(ctrl, port, ctrl->intr_type[port], m);
+	raw_spin_unlock_irqrestore(&ctrl->lock, flags);
+}
+
+static void realtek_gpio_irq_mask(struct irq_data *data)
+{
+	struct realtek_gpio_ctrl *ctrl = irq_data_to_ctrl(data);
+	unsigned int line = irqd_to_hwirq(data);
+	unsigned int port = line / 8;
+	unsigned int port_pin = line % 8;
+	unsigned long flags;
+	u16 m;
+
+	raw_spin_lock_irqsave(&ctrl->lock, flags);
+	m = ctrl->intr_mask[port];
+	m &= ~realtek_gpio_imr_bits(port_pin, REALTEK_GPIO_IMR_LINE_MASK);
+	ctrl->intr_mask[port] = m;
+	realtek_gpio_write_imr(ctrl, port, ctrl->intr_type[port], m);
+	raw_spin_unlock_irqrestore(&ctrl->lock, flags);
+}
+
+static int realtek_gpio_irq_set_type(struct irq_data *data, unsigned int flow_type)
+{
+	struct realtek_gpio_ctrl *ctrl = irq_data_to_ctrl(data);
+	unsigned int line = irqd_to_hwirq(data);
+	unsigned int port = line / 8;
+	unsigned int port_pin = line % 8;
+	unsigned long flags;
+	u16 type, t;
+
+	switch (flow_type & IRQ_TYPE_SENSE_MASK) {
+	case IRQ_TYPE_EDGE_FALLING:
+		type = REALTEK_GPIO_IRQ_EDGE_FALLING;
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		type = REALTEK_GPIO_IRQ_EDGE_RISING;
+		break;
+	case IRQ_TYPE_EDGE_BOTH:
+		type = REALTEK_GPIO_IRQ_EDGE_BOTH;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	irq_set_handler_locked(data, handle_edge_irq);
+
+	raw_spin_lock_irqsave(&ctrl->lock, flags);
+	t = ctrl->intr_type[port];
+	t &= ~realtek_gpio_imr_bits(port_pin, REALTEK_GPIO_IMR_LINE_MASK);
+	t |= realtek_gpio_imr_bits(port_pin, type);
+	ctrl->intr_type[port] = t;
+	realtek_gpio_write_imr(ctrl, port, t, ctrl->intr_mask[port]);
+	raw_spin_unlock_irqrestore(&ctrl->lock, flags);
+
+	return 0;
+}
+
+static void realtek_gpio_irq_handler(struct irq_desc *desc)
+{
+	struct gpio_chip *gc = irq_desc_get_handler_data(desc);
+	struct realtek_gpio_ctrl *ctrl = gpiochip_get_data(gc);
+	struct irq_chip *irq_chip = irq_desc_get_chip(desc);
+	unsigned int lines_done;
+	unsigned int port_pin_count;
+	unsigned int irq;
+	unsigned long status;
+	int offset;
+
+	chained_irq_enter(irq_chip, desc);
+
+	for (lines_done = 0; lines_done < gc->ngpio; lines_done += 8) {
+		status = realtek_gpio_read_isr(ctrl, lines_done / 8);
+		port_pin_count = min(gc->ngpio - lines_done, 8U);
+		for_each_set_bit(offset, &status, port_pin_count) {
+			irq = irq_find_mapping(gc->irq.domain, offset);
+			generic_handle_irq(irq);
+		}
+	}
+
+	chained_irq_exit(irq_chip, desc);
+}
+
+static int realtek_gpio_irq_init(struct gpio_chip *gc)
+{
+	struct realtek_gpio_ctrl *ctrl = gpiochip_get_data(gc);
+	unsigned int port;
+
+	for (port = 0; (port * 8) < gc->ngpio; port++) {
+		realtek_gpio_write_imr(ctrl, port, 0, 0);
+		realtek_gpio_clear_isr(ctrl, port, GENMASK(7, 0));
+	}
+
+	return 0;
+}
+
+static struct irq_chip realtek_gpio_irq_chip = {
+	.name = "realtek-otto-gpio",
+	.irq_ack = realtek_gpio_irq_ack,
+	.irq_mask = realtek_gpio_irq_mask,
+	.irq_unmask = realtek_gpio_irq_unmask,
+	.irq_set_type = realtek_gpio_irq_set_type,
+};
+
+static const struct of_device_id realtek_gpio_of_match[] = {
+	{
+		.compatible = "realtek,otto-gpio",
+		.data = (void *)GPIO_INTERRUPTS_DISABLED,
+	},
+	{
+		.compatible = "realtek,rtl8380-gpio",
+	},
+	{
+		.compatible = "realtek,rtl8390-gpio",
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(of, realtek_gpio_of_match);
+
+static int realtek_gpio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	unsigned int dev_flags;
+	struct gpio_irq_chip *girq;
+	struct realtek_gpio_ctrl *ctrl;
+	u32 ngpios;
+	int err, irq;
+
+	ctrl = devm_kzalloc(dev, sizeof(*ctrl), GFP_KERNEL);
+	if (!ctrl)
+		return -ENOMEM;
+
+	dev_flags = (unsigned int) device_get_match_data(dev);
+
+	ngpios = REALTEK_GPIO_MAX;
+	device_property_read_u32(dev, "ngpios", &ngpios);
+
+	if (ngpios > REALTEK_GPIO_MAX) {
+		dev_err(&pdev->dev, "invalid ngpios (max. %d)\n",
+			REALTEK_GPIO_MAX);
+		return -EINVAL;
+	}
+
+	ctrl->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(ctrl->base))
+		return PTR_ERR(ctrl->base);
+
+	raw_spin_lock_init(&ctrl->lock);
+
+	err = bgpio_init(&ctrl->gc, dev, 4,
+		ctrl->base + REALTEK_GPIO_REG_DATA, NULL, NULL,
+		ctrl->base + REALTEK_GPIO_REG_DIR, NULL,
+		BGPIOF_BIG_ENDIAN_BYTE_ORDER);
+	if (err) {
+		dev_err(dev, "unable to init generic GPIO");
+		return err;
+	}
+
+	ctrl->gc.ngpio = ngpios;
+	ctrl->gc.owner = THIS_MODULE;
+
+	irq = platform_get_irq_optional(pdev, 0);
+	if (!(dev_flags & GPIO_INTERRUPTS_DISABLED) && irq > 0) {
+		girq = &ctrl->gc.irq;
+		girq->chip = &realtek_gpio_irq_chip;
+		girq->default_type = IRQ_TYPE_NONE;
+		girq->handler = handle_bad_irq;
+		girq->parent_handler = realtek_gpio_irq_handler;
+		girq->num_parents = 1;
+		girq->parents = devm_kcalloc(dev, girq->num_parents,
+					sizeof(*girq->parents),	GFP_KERNEL);
+		if (!girq->parents)
+			return -ENOMEM;
+		girq->parents[0] = irq;
+		girq->init_hw = realtek_gpio_irq_init;
+	}
+
+	return devm_gpiochip_add_data(dev, &ctrl->gc, ctrl);
+}
+
+static struct platform_driver realtek_gpio_driver = {
+	.driver = {
+		.name = "realtek-otto-gpio",
+		.of_match_table	= realtek_gpio_of_match,
+	},
+	.probe = realtek_gpio_probe,
+};
+module_platform_driver(realtek_gpio_driver);
+
+MODULE_DESCRIPTION("Realtek Otto GPIO support");
+MODULE_AUTHOR("Sander Vanheule <sander@svanheule.net>");
+MODULE_LICENSE("GPL v2");