[PATCH v2 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          |    8 +
 drivers/gpio/Makefile         |    1 +
 drivers/gpio/gpio-lynxpoint.c |  469 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 478 insertions(+), 0 deletions(-)
 create mode 100644 drivers/gpio/gpio-lynxpoint.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index a22b5b7..46601a7 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -289,6 +289,14 @@ 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"
+	depends on ACPI
+	select IRQ_DOMAIN
+	help
+	  driver for GPIO functionality on Intel Lynxpoint PCH chipset
+	  Requires ACPI device enumeration 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 1d49aa7..2ad5cbd 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -31,6 +31,7 @@ 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..3472b05
--- /dev/null
+++ b/drivers/gpio/gpio-lynxpoint.c
@@ -0,0 +1,469 @@
+/*
+ * 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>
+#include <linux/pm_runtime.h>
+
+/* LynxPoint chipset has support for 94 gpio pins */
+
+#define LP_NUM_GPIO	94
+
+/* Bitmapped 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 long		reg_base;
+};
+
+/*
+ * Lynxpoint gpios are controlled through both bitmapped registers and
+ * per gpio specific registers. The bitmapped registers are in chunks of
+ * 3 x 32bit registers to cover all 94 gpios
+ *
+ * per gpio specific registers consist of two 32bit registers per gpio
+ * (LP_CONFIG1 and LP_CONFIG2), with 94 gpios there's a total of
+ * 188 config registes.
+ *
+ * A simplified view of the register layout look like this:
+ *
+ * LP_ACPI_OWNED[31:0] gpio ownerships for gpios 0-31  (bitmapped registers)
+ * LP_ACPI_OWNED[63:32] gpio ownerships for gpios 32-63
+ * LP_ACPI_OWNED[94:64] gpio ownerships for gpios 63-94
+ * ...
+ * LP_INT_ENABLE[31:0] ...
+ * LP_INT_ENABLE[63:31] ...
+ * LP_INT_ENABLE[94:64] ...
+ * LP0_CONFIG1 (gpio 0) config1 reg for gpio 0 (per gpio registers)
+ * LP0_CONFIG2 (gpio 0) config2 reg for gpio 0
+ * LP1_CONFIG1 (gpio 1) config1 reg for gpio 1
+ * LP1_CONFIG2 (gpio 1) config2 reg for gpio 1
+ * LP2_CONFIG1 (gpio 2) ...
+ * LP2_CONFIG2 (gpio 2) ...
+ * ...
+ * LP94_CONFIG1 (gpio 94) ...
+ * LP94_CONFIG2 (gpio 94) ...
+ */
+
+static unsigned long lp_gpio_reg(struct gpio_chip *chip, unsigned offset,
+				 int reg)
+{
+	struct lp_gpio *lg = container_of(chip, struct lp_gpio, chip);
+	int reg_offset;
+
+	if (reg == LP_CONFIG1 || reg == LP_CONFIG2)
+		/* per gpio specific config registers */
+		reg_offset = offset * 8;
+	else
+		/* bitmapped registers */
+		reg_offset = (offset / 32) * 4;
+
+	return lg->reg_base + reg + reg_offset;
+}
+
+static int lp_gpio_request(struct gpio_chip *chip, unsigned offset)
+{
+	struct lp_gpio *lg = container_of(chip, struct lp_gpio, chip);
+	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
+	unsigned long conf2 = lp_gpio_reg(chip, offset, LP_CONFIG2);
+	unsigned long acpi_use = lp_gpio_reg(chip, offset, LP_ACPI_OWNED);
+
+	pm_runtime_get(&lg->pdev->dev); /* should we put if failed */
+
+	/* Fail if BIOS reserved pin for ACPI use */
+	if (!(inl(acpi_use) & BIT(offset % 32))) {
+		dev_err(&lg->pdev->dev, "gpio %d reserved for ACPI\n", offset);
+		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 void lp_gpio_free(struct gpio_chip *chip, unsigned offset)
+{
+	struct lp_gpio *lg = container_of(chip, struct lp_gpio, chip);
+	unsigned long conf2 = lp_gpio_reg(chip, offset, LP_CONFIG2);
+
+	/* disable input sensing */
+	outl(inl(conf2) | GPINDIS_BIT, conf2);
+
+	pm_runtime_put(&lg->pdev->dev);
+}
+
+static int lp_irq_type(struct irq_data *d, unsigned type)
+{
+	struct lp_gpio *lg = irq_data_get_irq_chip_data(d);
+	u32 hwirq = irqd_to_hwirq(d);
+	unsigned long flags;
+	u32 value;
+	unsigned long reg = lp_gpio_reg(&lg->chip, hwirq, LP_CONFIG1);
+
+	if (hwirq >= 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 offset)
+{
+	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
+	return inl(reg) & IN_LVL_BIT;
+}
+
+static void lp_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct lp_gpio *lg = container_of(chip, struct lp_gpio, chip);
+	unsigned long reg = lp_gpio_reg(chip, offset, 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 offset)
+{
+	struct lp_gpio *lg = container_of(chip, struct lp_gpio, chip);
+	unsigned long reg = lp_gpio_reg(chip, offset, 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 offset, int value)
+{
+	struct lp_gpio *lg = container_of(chip, struct lp_gpio, chip);
+	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
+	unsigned long flags;
+
+	lp_gpio_set(chip, offset, 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 offset)
+{
+	struct lp_gpio *lg = container_of(chip, struct lp_gpio, chip);
+	return irq_create_mapping(lg->domain, offset);
+}
+
+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 = lp_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 hwirq = irqd_to_hwirq(d);
+	unsigned long reg = lp_gpio_reg(&lg->chip, hwirq, LP_INT_ENABLE);
+	unsigned long flags;
+
+	spin_lock_irqsave(&lg->lock, flags);
+	outl(inl(reg) | BIT(hwirq % 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 hwirq = irqd_to_hwirq(d);
+	unsigned long reg = lp_gpio_reg(&lg->chip, hwirq, LP_INT_ENABLE);
+	unsigned long flags;
+
+	spin_lock_irqsave(&lg->lock, flags);
+	outl(inl(reg) & ~BIT(hwirq % 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 = lp_gpio_reg(&lg->chip, base, LP_INT_ENABLE);
+		outl(0, reg);
+		/* Clear interrupt status register */
+		reg = lp_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 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;
+	unsigned long reg_len;
+	unsigned hwirq;
+	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;
+	reg_len = resource_size(io_rc);
+
+	if (!devm_request_region(dev, lg->reg_base, 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->free = lp_gpio_free;
+	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) {
+		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(hwirq, lg);
+		irq_set_chained_handler(hwirq, lp_gpio_irq_handler);
+	}
+
+	ret = gpiochip_add(gc);
+	if (ret) {
+		dev_err(dev, "failed adding lp-gpio chip\n");
+		return ret;
+	}
+	pm_runtime_enable(dev);
+
+	return 0;
+}
+
+static int lp_gpio_runtime_suspend(struct device *dev)
+{
+	return 0;
+}
+
+static int lp_gpio_runtime_resume(struct device *dev)
+{
+	return 0;
+}
+
+static const struct dev_pm_ops lp_gpio_pm_ops = {
+	.runtime_suspend = lp_gpio_runtime_suspend,
+	.runtime_resume = lp_gpio_runtime_resume,
+};
+
+static const struct acpi_device_id lynxpoint_gpio_acpi_match[] = {
+	{ "INT33C7", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, lynxpoint_gpio_acpi_match);
+
+static int 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         = lp_gpio_remove,
+	.driver         = {
+		.name   = "lp_gpio",
+		.owner  = THIS_MODULE,
+		.pm	= &lp_gpio_pm_ops,
+		.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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