[PATCH 1/1] gpio: add Lynxpoint chipset gpio driver.

[Mathias Nyman]

Add gpio support for Intel Lynxpoint chipset.
Lynxpoint supports 94 gpio pins which can generate interrupts.
Driver will fail requests for pins that are marked as owned by ACPI, or
set in an alternate mode (non-gpio).

Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
---
 drivers/gpio/Kconfig          |    7 +
 drivers/gpio/Makefile         |    1 +
 drivers/gpio/gpio-lynxpoint.c |  406 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 414 insertions(+), 0 deletions(-)
 create mode 100644 drivers/gpio/gpio-lynxpoint.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index f165576..e144bfa 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -267,6 +267,13 @@ config GPIO_GE_FPGA
 	  and write pin state) for GPIO implemented in a number of GE single
 	  board computers.
 
+config GPIO_LYNXPOINT
+	bool "Intel Lynxpoint GPIO support"
+	select IRQ_DOMAIN
+	help
+	  driver for GPIO functionality on Intel Lynxpoint PCH chipset
+	  Requires platform or ACPI code to set up a platform device.
+
 comment "I2C GPIO expanders:"
 
 config GPIO_ARIZONA
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 420dbac..e4af917 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_GPIO_JANZ_TTL)	+= gpio-janz-ttl.o
 obj-$(CONFIG_ARCH_KS8695)	+= gpio-ks8695.o
 obj-$(CONFIG_GPIO_LANGWELL)	+= gpio-langwell.o
 obj-$(CONFIG_ARCH_LPC32XX)	+= gpio-lpc32xx.o
+obj-$(CONFIG_GPIO_LYNXPOINT)	+= gpio-lynxpoint.o
 obj-$(CONFIG_GPIO_MAX730X)	+= gpio-max730x.o
 obj-$(CONFIG_GPIO_MAX7300)	+= gpio-max7300.o
 obj-$(CONFIG_GPIO_MAX7301)	+= gpio-max7301.o
diff --git a/drivers/gpio/gpio-lynxpoint.c b/drivers/gpio/gpio-lynxpoint.c
new file mode 100644
index 0000000..6c7f351
--- /dev/null
+++ b/drivers/gpio/gpio-lynxpoint.c
@@ -0,0 +1,406 @@
+/*
+ * GPIO controller driver for Intel Lynxpoint PCH chipset>
+ * Copyright (c) 2012, Intel Corporation.
+ *
+ * Author: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/gpio.h>
+#include <linux/irqdomain.h>
+#include <linux/slab.h>
+#include <linux/acpi.h>
+#include <linux/platform_device.h>
+
+/* LynxPoint chipset has support for 94 gpio pins */
+
+#define LP_NUM_GPIO	94
+
+/* Register offsets */
+#define LP_ACPI_OWNED	0x00 /* Bitmap, set by bios, 0: pin reserved for ACPI */
+#define LP_GC		0x7C /* set APIC IRQ to IRQ14 or IRQ15 for all pins */
+#define LP_INT_STAT	0x80
+#define LP_INT_ENABLE	0x90
+
+/* Each pin has two 32 bit config registers, starting at 0x100 */
+#define LP_CONFIG1	0x100
+#define LP_CONFIG2	0x104
+
+/* LP_CONFIG1 reg bits */
+#define OUT_LVL_BIT	BIT(31)
+#define IN_LVL_BIT	BIT(30)
+#define TRIG_SEL_BIT	BIT(4) /* 0: Edge, 1: Level */
+#define INT_INV_BIT	BIT(3) /* Invert interrupt triggering */
+#define DIR_BIT		BIT(2) /* 0: Output, 1: Input */
+#define USE_SEL_BIT	BIT(0) /* 0: Native, 1: GPIO */
+
+/* LP_CONFIG2 reg bits */
+#define GPINDIS_BIT	BIT(2) /* disable input sensing */
+#define GPIWP_BIT	(BIT(0) | BIT(1)) /* weak pull options */
+
+struct lp_gpio {
+	struct gpio_chip	chip;
+	struct irq_domain	*domain;
+	struct platform_device	*pdev;
+	spinlock_t		lock;
+	unsigned		hwirq;
+	unsigned long		reg_base;
+	unsigned long		reg_len;
+};
+
+static unsigned long gpio_reg(struct gpio_chip *chip, unsigned gpio, int reg)
+{
+	struct lp_gpio *lg = container_of(chip, struct lp_gpio, chip);
+	int offset;
+
+	if (reg == LP_CONFIG1 || reg == LP_CONFIG2)
+		offset = gpio * 8;
+	else
+		offset = (gpio / 32) * 4;
+
+	return lg->reg_base + reg + offset;
+}
+
+static int lp_gpio_request(struct gpio_chip *chip, unsigned gpio)
+{
+	struct lp_gpio *lg = container_of(chip, struct lp_gpio, chip);
+	unsigned long reg = gpio_reg(chip, gpio, LP_CONFIG1);
+	unsigned long conf2 = gpio_reg(chip, gpio, LP_CONFIG2);
+	unsigned long acpi_use = gpio_reg(chip, gpio, LP_ACPI_OWNED);
+
+	/* Fail if BIOS reserved pin for ACPI use */
+	if (!(inl(acpi_use) & BIT(gpio % 32))) {
+		dev_err(&lg->pdev->dev, "gpio %d reserved for ACPI\n", gpio);
+		return -EBUSY;
+	}
+	/* Fail if pin is in alternate function mode (not GPIO mode) */
+	if (!(inl(reg) & USE_SEL_BIT))
+		return -ENODEV;
+
+	/* enable input sensing */
+	outl(inl(conf2) & ~GPINDIS_BIT, conf2);
+
+	return 0;
+}
+
+static int lp_irq_type(struct irq_data *d, unsigned type)
+{
+	struct lp_gpio *lg = irq_data_get_irq_chip_data(d);
+	u32 gpio = irqd_to_hwirq(d);
+	unsigned long flags;
+	u32 value;
+	unsigned long reg = gpio_reg(&lg->chip, gpio, LP_CONFIG1);
+
+	if (gpio >= lg->chip.ngpio)
+		return -EINVAL;
+
+	spin_lock_irqsave(&lg->lock, flags);
+	value = inl(reg);
+
+	/* set both TRIG_SEL and INV bits to 0 for rising edge */
+	if (type & IRQ_TYPE_EDGE_RISING)
+		value &= ~(TRIG_SEL_BIT | INT_INV_BIT);
+
+	/* TRIG_SEL bit 0, INV bit 1 for falling edge */
+	if (type & IRQ_TYPE_EDGE_FALLING)
+		value = (value | INT_INV_BIT) & ~TRIG_SEL_BIT;
+
+	/* TRIG_SEL bit 1, INV bit 0 for level low */
+	if (type & IRQ_TYPE_LEVEL_LOW)
+		value = (value | TRIG_SEL_BIT) & ~INT_INV_BIT;
+
+	/* TRIG_SEL bit 1, INV bit 1 for level high */
+	if (type & IRQ_TYPE_LEVEL_HIGH)
+		value |= TRIG_SEL_BIT | INT_INV_BIT;
+
+	outl(value, reg);
+	spin_unlock_irqrestore(&lg->lock, flags);
+
+	return 0;
+}
+
+static int lp_gpio_get(struct gpio_chip *chip, unsigned gpio)
+{
+	unsigned long reg = gpio_reg(chip, gpio, LP_CONFIG1);
+	return inl(reg) & IN_LVL_BIT;
+}
+
+static void lp_gpio_set(struct gpio_chip *chip, unsigned gpio, int value)
+{
+	struct lp_gpio *lg = container_of(chip, struct lp_gpio, chip);
+	unsigned long reg = gpio_reg(chip, gpio, LP_CONFIG1);
+	unsigned long flags;
+
+	spin_lock_irqsave(&lg->lock, flags);
+
+	if (value)
+		outl(inl(reg) | OUT_LVL_BIT, reg);
+	else
+		outl(inl(reg) & ~OUT_LVL_BIT, reg);
+
+	spin_unlock_irqrestore(&lg->lock, flags);
+}
+
+static int lp_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
+{
+	struct lp_gpio *lg = container_of(chip, struct lp_gpio, chip);
+	unsigned long reg = gpio_reg(chip, gpio, LP_CONFIG1);
+	unsigned long flags;
+
+	spin_lock_irqsave(&lg->lock, flags);
+	outl(inl(reg) | DIR_BIT, reg);
+	spin_unlock_irqrestore(&lg->lock, flags);
+
+	return 0;
+}
+
+static int lp_gpio_direction_output(struct gpio_chip *chip,
+				      unsigned gpio, int value)
+{
+	struct lp_gpio *lg = container_of(chip, struct lp_gpio, chip);
+	unsigned long reg = gpio_reg(chip, gpio, LP_CONFIG1);
+	unsigned long flags;
+
+	lp_gpio_set(chip, gpio, value);
+
+	spin_lock_irqsave(&lg->lock, flags);
+	outl(inl(reg) & ~DIR_BIT, reg);
+	spin_unlock_irqrestore(&lg->lock, flags);
+
+	return 0;
+}
+
+static int lp_gpio_to_irq(struct gpio_chip *chip, unsigned gpio)
+{
+	struct lp_gpio *lg = container_of(chip, struct lp_gpio, chip);
+	return irq_create_mapping(lg->domain, gpio);
+}
+
+static void lp_gpio_irq_handler(unsigned irq, struct irq_desc *desc)
+{
+	struct irq_data *data = irq_desc_get_irq_data(desc);
+	struct lp_gpio *lg = irq_data_get_irq_handler_data(data);
+	struct irq_chip *chip = irq_data_get_irq_chip(data);
+	u32 base, pin, mask;
+	unsigned long reg, pending;
+	unsigned virq;
+
+	/* check from GPIO controller which pin triggered the interrupt */
+	for (base = 0; base < lg->chip.ngpio; base += 32) {
+		reg = gpio_reg(&lg->chip, base, LP_INT_STAT);
+
+		while ((pending = inl(reg))) {
+			pin = __ffs(pending);
+			mask = BIT(pin);
+			/* Clear before handling so we don't lose an edge */
+			outl(mask, reg);
+			virq = irq_find_mapping(lg->domain, base + pin);
+			generic_handle_irq(virq);
+		}
+	}
+	chip->irq_eoi(data);
+}
+
+static void lp_irq_unmask(struct irq_data *d)
+{
+}
+
+static void lp_irq_mask(struct irq_data *d)
+{
+}
+
+static void lp_irq_enable(struct irq_data *d)
+{
+	struct lp_gpio *lg = irq_data_get_irq_chip_data(d);
+	u32 gpio = irqd_to_hwirq(d);
+	unsigned long reg = gpio_reg(&lg->chip, gpio, LP_INT_ENABLE);
+	unsigned long flags;
+
+	spin_lock_irqsave(&lg->lock, flags);
+	outl(inl(reg) | BIT(gpio % 32), reg);
+	spin_unlock_irqrestore(&lg->lock, flags);
+}
+
+static void lp_irq_disable(struct irq_data *d)
+{
+	struct lp_gpio *lg = irq_data_get_irq_chip_data(d);
+	u32 gpio = irqd_to_hwirq(d);
+	unsigned long reg = gpio_reg(&lg->chip, gpio, LP_INT_ENABLE);
+	unsigned long flags;
+
+	spin_lock_irqsave(&lg->lock, flags);
+	outl(inl(reg) & ~BIT(gpio % 32), reg);
+	spin_unlock_irqrestore(&lg->lock, flags);
+}
+
+static struct irq_chip lp_irqchip = {
+	.name = "LP-GPIO",
+	.irq_mask = lp_irq_mask,
+	.irq_unmask = lp_irq_unmask,
+	.irq_enable = lp_irq_enable,
+	.irq_disable = lp_irq_disable,
+	.irq_set_type = lp_irq_type,
+	.flags = IRQCHIP_SKIP_SET_WAKE,
+};
+
+static void lp_gpio_irq_init_hw(struct lp_gpio *lg)
+{
+	unsigned long reg;
+	unsigned base;
+
+	for (base = 0; base < lg->chip.ngpio; base += 32) {
+		/* disable gpio pin interrupts */
+		reg = gpio_reg(&lg->chip, base, LP_INT_ENABLE);
+		outl(0, reg);
+		/* Clear interrupt status register */
+		reg = gpio_reg(&lg->chip, base, LP_INT_STAT);
+		outl(0xffffffff, reg);
+	}
+}
+
+static int lp_gpio_irq_map(struct irq_domain *d, unsigned int virq,
+			    irq_hw_number_t hw)
+{
+	struct lp_gpio *lg = d->host_data;
+
+	irq_set_chip_and_handler_name(virq, &lp_irqchip, handle_simple_irq,
+				      "demux");
+	irq_set_chip_data(virq, lg);
+	irq_set_irq_type(virq, IRQ_TYPE_NONE);
+
+	return 0;
+}
+
+static const struct irq_domain_ops lp_gpio_irq_ops = {
+	.map = lp_gpio_irq_map,
+};
+
+static int __devinit lp_gpio_probe(struct platform_device *pdev)
+{
+	struct lp_gpio *lg;
+	struct gpio_chip *gc;
+	struct resource *io_rc, *irq_rc;
+	struct device *dev = &pdev->dev;
+	int ret = -ENODEV;
+
+	lg = devm_kzalloc(dev, sizeof(struct lp_gpio), GFP_KERNEL);
+	if (!lg) {
+		dev_err(dev, "can't allocate lp_gpio chip data\n");
+		return -ENOMEM;
+	}
+
+	lg->pdev = pdev;
+	platform_set_drvdata(pdev, lg);
+
+	io_rc = platform_get_resource(pdev, IORESOURCE_IO, 0);
+	irq_rc = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+
+	if (!io_rc) {
+		dev_err(dev, "missing IO resources\n");
+		return -EINVAL;
+	}
+
+	lg->reg_base = io_rc->start;
+	lg->reg_len = resource_size(io_rc);
+
+	if (!devm_request_region(dev, lg->reg_base, lg->reg_len, "lp-gpio")) {
+		dev_err(dev, "failed requesting IO region 0x%x\n",
+			(unsigned int)lg->reg_base);
+		return -EBUSY;
+	}
+
+	spin_lock_init(&lg->lock);
+
+	gc = &lg->chip;
+	gc->label = dev_name(dev);
+	gc->owner = THIS_MODULE;
+	gc->request = lp_gpio_request;
+	gc->direction_input = lp_gpio_direction_input;
+	gc->direction_output = lp_gpio_direction_output;
+	gc->get = lp_gpio_get;
+	gc->set = lp_gpio_set;
+	gc->base = -1;
+	gc->ngpio = LP_NUM_GPIO;
+	gc->can_sleep = 0;
+	gc->dev = dev;
+
+	/* set up interrupts  */
+	if (irq_rc && irq_rc->start) {
+		lg->hwirq = irq_rc->start;
+		gc->to_irq = lp_gpio_to_irq;
+
+		lg->domain = irq_domain_add_linear(NULL, LP_NUM_GPIO,
+						   &lp_gpio_irq_ops, lg);
+		if (!lg->domain)
+			return -ENXIO;
+
+		lp_gpio_irq_init_hw(lg);
+
+		irq_set_handler_data(lg->hwirq, lg);
+		irq_set_chained_handler(lg->hwirq, lp_gpio_irq_handler);
+	}
+
+	ret = gpiochip_add(gc);
+	if (ret) {
+		dev_err(dev, "failed adding lp-gpio chip\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id lynxpoint_gpio_acpi_match[] = {
+	{ "INT33C7", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, lynxpoint_gpio_acpi_match);
+#endif
+
+static int __devexit lp_gpio_remove(struct platform_device *pdev)
+{
+	struct lp_gpio *lg = platform_get_drvdata(pdev);
+	int err;
+	err = gpiochip_remove(&lg->chip);
+	if (err)
+		dev_warn(&pdev->dev, "failed to remove gpio_chip.\n");
+	platform_set_drvdata(pdev, NULL);
+	return 0;
+}
+
+static struct platform_driver lp_gpio_driver = {
+	.probe          = lp_gpio_probe,
+	.remove         = __devexit_p(lp_gpio_remove),
+	.driver         = {
+		.name   = "lp_gpio",
+		.owner  = THIS_MODULE,
+		.acpi_match_table = ACPI_PTR(lynxpoint_gpio_acpi_match),
+	},
+};
+
+static int __init lp_gpio_init(void)
+{
+	return platform_driver_register(&lp_gpio_driver);
+}
+
+subsys_initcall(lp_gpio_init);
-- 
1.7.4.1

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