[PATCH v3 1/1] gpio: merrifield: Introduce GPIO driver to support Merrifield

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

Intel Merrifield platform has a special GPIO controller to drive pads when they
are muxed in corresponding mode.

Intel Merrifield GPIO IP is slightly different here and there in comparison to
the older Intel MID platforms. These differences include in particular the
shaked register offsets, specific support of level triggered interrupts and
wake capable sources, as well as a pinctrl which is a separate IP.

Instead of uglifying existing driver I decide to provide a new one slightly
based on gpio-intel-mid.c. So, anyone can easily compare what changes are
happened to be here.

Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
In v3:
- protect irq_set_wake() by spin lock
- add Mika's Ack (hope it's still valid)

 drivers/gpio/Kconfig           |   7 +
 drivers/gpio/Makefile          |   1 +
 drivers/gpio/gpio-merrifield.c | 443 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 451 insertions(+)
 create mode 100644 drivers/gpio/gpio-merrifield.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 3d0c297..7880894 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1032,6 +1032,13 @@ config GPIO_INTEL_MID
 	help
 	  Say Y here to support Intel MID GPIO.
 
+config GPIO_MERRIFIELD
+	tristate "Intel Merrifield GPIO support"
+	depends on X86_INTEL_MID
+	select GPIOLIB_IRQCHIP
+	help
+	  Say Y here to support Intel Merrifield GPIO.
+
 config GPIO_ML_IOH
 	tristate "OKI SEMICONDUCTOR ML7213 IOH GPIO support"
 	select GENERIC_IRQ_CHIP
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 991598e..d6ba958 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -63,6 +63,7 @@ obj-$(CONFIG_GPIO_MAX7301)	+= gpio-max7301.o
 obj-$(CONFIG_GPIO_MAX732X)	+= gpio-max732x.o
 obj-$(CONFIG_GPIO_MB86S7X)	+= gpio-mb86s7x.o
 obj-$(CONFIG_GPIO_MENZ127)	+= gpio-menz127.o
+obj-$(CONFIG_GPIO_MERRIFIELD)	+= gpio-merrifield.o
 obj-$(CONFIG_GPIO_MC33880)	+= gpio-mc33880.o
 obj-$(CONFIG_GPIO_MC9S08DZ60)	+= gpio-mc9s08dz60.o
 obj-$(CONFIG_GPIO_MCP23S08)	+= gpio-mcp23s08.o
diff --git a/drivers/gpio/gpio-merrifield.c b/drivers/gpio/gpio-merrifield.c
new file mode 100644
index 0000000..8ad6bf2
--- /dev/null
+++ b/drivers/gpio/gpio-merrifield.c
@@ -0,0 +1,443 @@
+/*
+ * Intel Merrifield SoC GPIO driver
+ *
+ * Copyright (c) 2016 Intel Corporation.
+ * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/bitops.h>
+#include <linux/gpio/driver.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/pinctrl/consumer.h>
+
+#define GCCR		0x000	/* controller configuration */
+#define GPLR		0x004	/* pin level r/o */
+#define GPDR		0x01c	/* pin direction */
+#define GPSR		0x034	/* pin set w/o */
+#define GPCR		0x04c	/* pin clear w/o */
+#define GRER		0x064	/* rising edge detect */
+#define GFER		0x07c	/* falling edge detect */
+#define GFBR		0x094	/* glitch filter bypass */
+#define GIMR		0x0ac	/* interrupt mask */
+#define GISR		0x0c4	/* interrupt source */
+#define GITR		0x300	/* input type */
+#define GLPR		0x318	/* level input polarity */
+#define GWMR		0x400	/* wake mask */
+#define GWSR		0x418	/* wake source */
+#define GSIR		0xc00	/* secure input */
+
+/* Intel Merrifield has 192 GPIO pins */
+#define MRFLD_NGPIO	192
+
+struct mrfld_gpio_pinrange {
+	unsigned int gpio_base;
+	unsigned int pin_base;
+	unsigned int npins;
+};
+
+#define GPIO_PINRANGE(gstart, gend, pstart)		\
+	{						\
+		.gpio_base = (gstart),			\
+		.pin_base = (pstart),			\
+		.npins = (gend) - (gstart) + 1,		\
+	}
+
+struct mrfld_gpio {
+	struct gpio_chip	chip;
+	void __iomem		*reg_base;
+	raw_spinlock_t		lock;
+	struct device		*dev;
+};
+
+static const struct mrfld_gpio_pinrange mrfld_gpio_ranges[] = {
+	GPIO_PINRANGE(0, 11, 146),
+	GPIO_PINRANGE(12, 13, 144),
+	GPIO_PINRANGE(14, 15, 35),
+	GPIO_PINRANGE(16, 16, 164),
+	GPIO_PINRANGE(17, 18, 105),
+	GPIO_PINRANGE(19, 22, 101),
+	GPIO_PINRANGE(23, 30, 107),
+	GPIO_PINRANGE(32, 43, 67),
+	GPIO_PINRANGE(44, 63, 195),
+	GPIO_PINRANGE(64, 67, 140),
+	GPIO_PINRANGE(68, 69, 165),
+	GPIO_PINRANGE(70, 71, 65),
+	GPIO_PINRANGE(72, 76, 228),
+	GPIO_PINRANGE(77, 86, 37),
+	GPIO_PINRANGE(87, 87, 48),
+	GPIO_PINRANGE(88, 88, 47),
+	GPIO_PINRANGE(89, 96, 49),
+	GPIO_PINRANGE(97, 97, 34),
+	GPIO_PINRANGE(102, 119, 83),
+	GPIO_PINRANGE(120, 123, 79),
+	GPIO_PINRANGE(124, 135, 115),
+	GPIO_PINRANGE(137, 142, 158),
+	GPIO_PINRANGE(154, 163, 24),
+	GPIO_PINRANGE(164, 176, 215),
+	GPIO_PINRANGE(177, 189, 127),
+	GPIO_PINRANGE(190, 191, 178),
+};
+
+static void __iomem *gpio_reg(struct gpio_chip *chip, unsigned int offset,
+			      unsigned int reg_type_offset)
+{
+	struct mrfld_gpio *priv = gpiochip_get_data(chip);
+	u8 reg = offset / 32;
+
+	return priv->reg_base + reg_type_offset + reg * 4;
+}
+
+static int mrfld_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+	void __iomem *gplr = gpio_reg(chip, offset, GPLR);
+
+	return !!(readl(gplr) & BIT(offset % 32));
+}
+
+static void mrfld_gpio_set(struct gpio_chip *chip, unsigned int offset,
+			   int value)
+{
+	void __iomem *gpsr, *gpcr;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&priv->lock, flags);
+
+	if (value) {
+		gpsr = gpio_reg(chip, offset, GPSR);
+		writel(BIT(offset % 32), gpsr);
+	} else {
+		gpcr = gpio_reg(chip, offset, GPCR);
+		writel(BIT(offset % 32), gpcr);
+	}
+
+	raw_spin_unlock_irqrestore(&priv->lock, flags);
+}
+
+static int mrfld_gpio_direction_input(struct gpio_chip *chip,
+				      unsigned int offset)
+{
+	struct mrfld_gpio *priv = gpiochip_get_data(chip);
+	void __iomem *gpdr = gpio_reg(chip, offset, GPDR);
+	unsigned long flags;
+	u32 value;
+
+	raw_spin_lock_irqsave(&priv->lock, flags);
+
+	value = readl(gpdr);
+	value &= ~BIT(offset % 32);
+	writel(value, gpdr);
+
+	raw_spin_unlock_irqrestore(&priv->lock, flags);
+
+	return 0;
+}
+
+static int mrfld_gpio_direction_output(struct gpio_chip *chip,
+				       unsigned int offset, int value)
+{
+	struct mrfld_gpio *priv = gpiochip_get_data(chip);
+	void __iomem *gpdr = gpio_reg(chip, offset, GPDR);
+	unsigned long flags;
+
+	mrfld_gpio_set(chip, offset, value);
+
+	raw_spin_lock_irqsave(&priv->lock, flags);
+
+	value = readl(gpdr);
+	value |= BIT(offset % 32);
+	writel(value, gpdr);
+
+	raw_spin_unlock_irqrestore(&priv->lock, flags);
+
+	return 0;
+}
+
+static void mrfld_irq_ack(struct irq_data *d)
+{
+	struct mrfld_gpio *priv = irq_data_get_irq_chip_data(d);
+	u32 gpio = irqd_to_hwirq(d);
+	void __iomem *gisr = gpio_reg(&priv->chip, gpio, GISR);
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&priv->lock, flags);
+
+	writel(BIT(gpio % 32), gisr);
+
+	raw_spin_unlock_irqrestore(&priv->lock, flags);
+}
+
+static void mrfld_irq_unmask_mask(struct irq_data *d, bool unmask)
+{
+	struct mrfld_gpio *priv = irq_data_get_irq_chip_data(d);
+	u32 gpio = irqd_to_hwirq(d);
+	void __iomem *gimr = gpio_reg(&priv->chip, gpio, GIMR);
+	unsigned long flags;
+	u32 value;
+
+	raw_spin_lock_irqsave(&priv->lock, flags);
+
+	if (unmask)
+		value = readl(gimr) | BIT(gpio % 32);
+	else
+		value = readl(gimr) & ~BIT(gpio % 32);
+	writel(value, gimr);
+
+	raw_spin_unlock_irqrestore(&priv->lock, flags);
+}
+
+static void mrfld_irq_mask(struct irq_data *d)
+{
+	mrfld_irq_unmask_mask(d, false);
+}
+
+static void mrfld_irq_unmask(struct irq_data *d)
+{
+	mrfld_irq_unmask_mask(d, true);
+}
+
+static int mrfld_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct mrfld_gpio *priv = gpiochip_get_data(gc);
+	u32 gpio = irqd_to_hwirq(d);
+	void __iomem *grer = gpio_reg(&priv->chip, gpio, GRER);
+	void __iomem *gfer = gpio_reg(&priv->chip, gpio, GFER);
+	void __iomem *gitr = gpio_reg(&priv->chip, gpio, GITR);
+	void __iomem *glpr = gpio_reg(&priv->chip, gpio, GLPR);
+	unsigned long flags;
+	u32 value;
+
+	raw_spin_lock_irqsave(&priv->lock, flags);
+
+	if (type & IRQ_TYPE_EDGE_RISING)
+		value = readl(grer) | BIT(gpio % 32);
+	else
+		value = readl(grer) & ~BIT(gpio % 32);
+	writel(value, grer);
+
+	if (type & IRQ_TYPE_EDGE_FALLING)
+		value = readl(gfer) | BIT(gpio % 32);
+	else
+		value = readl(gfer) & ~BIT(gpio % 32);
+	writel(value, gfer);
+
+	/*
+	 * To prevent glitches from triggering an unintended level interrupt,
+	 * configure GLPR register first and then configure GITR.
+	 */
+	if (type & IRQ_TYPE_LEVEL_LOW)
+		value = readl(glpr) | BIT(gpio % 32);
+	else
+		value = readl(glpr) & ~BIT(gpio % 32);
+	writel(value, glpr);
+
+	if (type & IRQ_TYPE_LEVEL_MASK) {
+		value = readl(gitr) | BIT(gpio % 32);
+		writel(value, gitr);
+
+		irq_set_handler_locked(d, handle_level_irq);
+	} else if (type & IRQ_TYPE_EDGE_BOTH) {
+		value = readl(gitr) & ~BIT(gpio % 32);
+		writel(value, gitr);
+
+		irq_set_handler_locked(d, handle_edge_irq);
+	}
+
+	raw_spin_unlock_irqrestore(&priv->lock, flags);
+
+	return 0;
+}
+
+static int mrfld_irq_set_wake(struct irq_data *d, unsigned int on)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct mrfld_gpio *priv = gpiochip_get_data(gc);
+	u32 gpio = irqd_to_hwirq(d);
+	void __iomem *gwmr = gpio_reg(&priv->chip, gpio, GWMR);
+	void __iomem *gwsr = gpio_reg(&priv->chip, gpio, GWSR);
+	unsigned long flags;
+	u32 value;
+
+	raw_spin_lock_irqsave(&priv->lock, flags);
+
+	/* Clear the existing wake status */
+	writel(BIT(gpio % 32), gwsr);
+
+	if (on)
+		value = readl(gwmr) | BIT(gpio % 32);
+	else
+		value = readl(gwmr) & ~BIT(gpio % 32);
+	writel(value, gwmr);
+
+	raw_spin_unlock_irqrestore(&priv->lock, flags);
+
+	dev_dbg(priv->dev, "%sable wake for gpio %u\n", on ? "en" : "dis", gpio);
+	return 0;
+}
+
+static struct irq_chip mrfld_irqchip = {
+	.name		= "gpio-merrifield",
+	.irq_ack	= mrfld_irq_ack,
+	.irq_mask	= mrfld_irq_mask,
+	.irq_unmask	= mrfld_irq_unmask,
+	.irq_set_type	= mrfld_irq_set_type,
+	.irq_set_wake	= mrfld_irq_set_wake,
+};
+
+static void mrfld_irq_handler(struct irq_desc *desc)
+{
+	struct gpio_chip *gc = irq_desc_get_handler_data(desc);
+	struct mrfld_gpio *priv = gpiochip_get_data(gc);
+	struct irq_chip *irqchip = irq_desc_get_chip(desc);
+	unsigned long base, gpio;
+
+	chained_irq_enter(irqchip, desc);
+
+	/* Check GPIO controller to check which pin triggered the interrupt */
+	for (base = 0; base < priv->chip.ngpio; base += 32) {
+		void __iomem *gisr = gpio_reg(&priv->chip, base, GISR);
+		void __iomem *gimr = gpio_reg(&priv->chip, base, GIMR);
+		unsigned long pending, enabled;
+
+		pending = readl(gisr);
+		enabled = readl(gimr);
+
+		/* Only interrupts that are enabled */
+		pending &= enabled;
+
+		for_each_set_bit(gpio, &pending, 32) {
+			unsigned int irq;
+
+			irq = irq_find_mapping(gc->irqdomain, base + gpio);
+			generic_handle_irq(irq);
+		}
+	}
+
+	chained_irq_exit(irqchip, desc);
+}
+
+static void mrfld_irq_init_hw(struct mrfld_gpio *priv)
+{
+	void __iomem *reg;
+	unsigned int base;
+
+	for (base = 0; base < priv->chip.ngpio; base += 32) {
+		/* Clear the rising-edge detect register */
+		reg = gpio_reg(&priv->chip, base, GRER);
+		writel(0, reg);
+		/* Clear the falling-edge detect register */
+		reg = gpio_reg(&priv->chip, base, GFER);
+		writel(0, reg);
+	}
+}
+
+static int mrfld_gpio_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+	const struct mrfld_gpio_pinrange *range;
+	struct mrfld_gpio *priv;
+	u32 gpio_base, irq_base;
+	void __iomem *base;
+	unsigned int i;
+	int retval;
+
+	retval = pcim_enable_device(pdev);
+	if (retval)
+		return retval;
+
+	retval = pcim_iomap_regions(pdev, BIT(1) | BIT(0), pci_name(pdev));
+	if (retval) {
+		dev_err(&pdev->dev, "I/O memory mapping error\n");
+		return retval;
+	}
+
+	base = pcim_iomap_table(pdev)[1];
+
+	irq_base = readl(base);
+	gpio_base = readl(sizeof(u32) + base);
+
+	/* Release the IO mapping, since we already get the info from BAR1 */
+	pcim_iounmap_regions(pdev, BIT(1));
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv) {
+		dev_err(&pdev->dev, "can't allocate chip data\n");
+		return -ENOMEM;
+	}
+
+	priv->dev = &pdev->dev;
+	priv->reg_base = pcim_iomap_table(pdev)[0];
+
+	priv->chip.label = dev_name(&pdev->dev);
+	priv->chip.parent = &pdev->dev;
+	priv->chip.request = gpiochip_generic_request;
+	priv->chip.free = gpiochip_generic_free;
+	priv->chip.direction_input = mrfld_gpio_direction_input;
+	priv->chip.direction_output = mrfld_gpio_direction_output;
+	priv->chip.get = mrfld_gpio_get;
+	priv->chip.set = mrfld_gpio_set;
+	priv->chip.base = gpio_base;
+	priv->chip.ngpio = MRFLD_NGPIO;
+	priv->chip.can_sleep = false;
+
+	raw_spin_lock_init(&priv->lock);
+
+	pci_set_drvdata(pdev, priv);
+	retval = devm_gpiochip_add_data(&pdev->dev, &priv->chip, priv);
+	if (retval) {
+		dev_err(&pdev->dev, "gpiochip_add error %d\n", retval);
+		return retval;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(mrfld_gpio_ranges); i++) {
+		range = &mrfld_gpio_ranges[i];
+		retval = gpiochip_add_pin_range(&priv->chip,
+						"pinctrl-merrifield",
+						range->gpio_base,
+						range->pin_base,
+						range->npins);
+		if (retval) {
+			dev_err(&pdev->dev, "failed to add GPIO pin range\n");
+			return retval;
+		}
+	}
+
+	retval = gpiochip_irqchip_add(&priv->chip, &mrfld_irqchip, irq_base,
+				      handle_simple_irq, IRQ_TYPE_NONE);
+	if (retval) {
+		dev_err(&pdev->dev, "could not connect irqchip to gpiochip\n");
+		return retval;
+	}
+
+	mrfld_irq_init_hw(priv);
+
+	gpiochip_set_chained_irqchip(&priv->chip, &mrfld_irqchip, pdev->irq,
+				     mrfld_irq_handler);
+
+	return 0;
+}
+
+static const struct pci_device_id mrfld_gpio_ids[] = {
+	{ PCI_VDEVICE(INTEL, 0x1199) },
+	{ }
+};
+MODULE_DEVICE_TABLE(pci, mrfld_gpio_ids);
+
+static struct pci_driver mrfld_gpio_driver = {
+	.name		= "gpio-merrifield",
+	.id_table	= mrfld_gpio_ids,
+	.probe		= mrfld_gpio_probe,
+};
+
+module_pci_driver(mrfld_gpio_driver);
+
+MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
+MODULE_DESCRIPTION("Intel Merrifield SoC GPIO driver");
+MODULE_LICENSE("GPL v2");
-- 
2.8.1