Date:	Thu, 13 Jun 2013 18:06:23 +0300
From:	Mathias Nyman <mathias.nyman@...ux.intel.com>
To:	Linus <linus.walleij@...aro.org>
Cc:	<grant.likely@...retlab.ca>, <linux-kernel@...r.kernel.org>,
	Mathias Nyman <mathias.nyman@...ux.intel.com>
Subject: [PATCH v2 1/1] gpio: add Intel BayTrail gpio driver

Add support for gpio on Intel BayTrail platforms. BayTrail supports 3 banks
of gpios called SCORE, NCORE ans SUS with 102, 28 and 44 gpio pins.
Supports gpio interrupts and ACPI gpio events.

Signed-off-by: Mathias Nyman <mathias.nyman@...ux.intel.com>
---
 drivers/gpio/Kconfig         |   12 +
 drivers/gpio/Makefile        |    1 +
 drivers/gpio/gpio-baytrail.c |  547 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 560 insertions(+), 0 deletions(-)
 create mode 100644 drivers/gpio/gpio-baytrail.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 573c449..b712006 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -108,6 +108,18 @@ config GPIO_MAX730X
 
 comment "Memory mapped GPIO drivers:"
 
+config GPIO_BAYTRAIL
+	bool "Intel Baytrail GPIO support"
+	depends on ACPI && X86
+	select IRQ_DOMAIN
+	help
+	  driver for memory mapped GPIO functionality on Intel Baytrail
+	  platforms. Supports 3 banks with 102, 28 and 44 gpios.
+	  Most pins are usually muxed to some other functionality by firmware,
+	  so only a small amount is available for gpio use.
+
+	  Requires ACPI device enumeration code to set up a platform device.
+
 config GPIO_CLPS711X
 	def_bool y
 	depends on ARCH_CLPS711X
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 0cb2d65..bc1f6b3 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_GPIO_ADP5520)	+= gpio-adp5520.o
 obj-$(CONFIG_GPIO_ADP5588)	+= gpio-adp5588.o
 obj-$(CONFIG_GPIO_AMD8111)	+= gpio-amd8111.o
 obj-$(CONFIG_GPIO_ARIZONA)	+= gpio-arizona.o
+obj-$(CONFIG_GPIO_BAYTRAIL)	+= gpio-baytrail.o
 obj-$(CONFIG_GPIO_BT8XX)	+= gpio-bt8xx.o
 obj-$(CONFIG_GPIO_CLPS711X)	+= gpio-clps711x.o
 obj-$(CONFIG_GPIO_CS5535)	+= gpio-cs5535.o
diff --git a/drivers/gpio/gpio-baytrail.c b/drivers/gpio/gpio-baytrail.c
new file mode 100644
index 0000000..55efbdc
--- /dev/null
+++ b/drivers/gpio/gpio-baytrail.c
@@ -0,0 +1,547 @@
+/*
+ * GPIO driver for Intel Baytrail
+ * Copyright (c) 2012-2013, Intel Corporation.
+ *
+ * Author: Mathias Nyman <mathias.nyman@...ux.intel.com>
+ *
+ * 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/acpi.h>
+#include <linux/acpi_gpio.h>
+#include <linux/platform_device.h>
+#include <linux/seq_file.h>
+#include <linux/io.h>
+#include <linux/pm_runtime.h>
+
+/* memory mapped register offsets */
+#define BYT_CONF0_REG		0x000
+#define BYT_CONF1_REG		0x004
+#define BYT_VAL_REG		0x008
+#define BYT_DFT_REG		0x00c
+#define BYT_INT_STAT_REG	0x800
+
+/* BYT_CONF0_REG register bits */
+#define BYT_TRIG_NEG		BIT(26)
+#define BYT_TRIG_POS		BIT(25)
+#define BYT_TRIG_LVL		BIT(24)
+#define BYT_PIN_MUX		0x07
+
+/* BYT_VAL_REG register bits */
+#define BYT_INPUT_EN		BIT(2)  /* 0: input enabled (active low)*/
+#define BYT_OUTPUT_EN		BIT(1)  /* 0: output enabled (active low)*/
+#define BYT_LEVEL		BIT(0)
+
+#define BYT_DIR_MASK		(BIT(1) | BIT(2))
+#define BYT_TRIG_MASK		(BIT(26) | BIT(25) | BIT(24))
+
+#define BYT_NGPIO_SCORE		102
+#define BYT_NGPIO_NCORE		28
+#define BYT_NGPIO_SUS		44
+
+/*
+ * Baytrail gpio controller consist of three separate sub-controllers called
+ * SCORE, NCORE and SUS. The sub-controllers are identified by their acpi UID.
+ *
+ * GPIO numbering is _not_ ordered meaning that gpio # 0 in ACPI namespace does
+ * _not_ correspond to the first gpio register at controller's gpio base.
+ * There is no logic or pattern in mapping gpio numbers to registers (pads) so
+ * each sub-controller needs to have its own mapping table
+ */
+
+static unsigned score_gpio_to_pad[BYT_NGPIO_SCORE] = {
+	85, 89, 93, 96, 99, 102, 98, 101, 34, 37,
+	36, 38, 39, 35, 40, 84, 62, 61, 64, 59,
+	54, 56, 60, 55, 63, 57, 51, 50, 53, 47,
+	52, 49, 48, 43, 46, 41, 45, 42, 58, 44,
+	95, 105, 70, 68, 67, 66, 69, 71, 65, 72,
+	86, 90, 88, 92, 103, 77, 79, 83, 78, 81,
+	80, 82, 13, 12, 15, 14, 17, 18, 19, 16,
+	2, 1, 0, 4, 6, 7, 9, 8, 33, 32,
+	31, 30, 29, 27, 25, 28, 26, 23, 21, 20,
+	24, 22, 5, 3, 10, 11, 106, 87, 91, 104,
+	97, 100,
+};
+
+static unsigned ncore_gpio_to_pad[BYT_NGPIO_NCORE] = {
+	19, 18, 17, 20, 21, 22, 24, 25, 23, 16,
+	14, 15, 12, 26, 27, 1, 4, 8, 11, 0,
+	3, 6, 10, 13, 2, 5, 9, 7,
+};
+
+static unsigned sus_gpio_to_pad[BYT_NGPIO_SUS] = {
+	29, 33, 30, 31, 32, 34, 36, 35, 38, 37,
+	18, 7, 11, 20, 17, 1, 8, 10, 19, 12,
+	0, 2, 23, 39, 28, 27, 22, 21, 24, 25,
+	26, 51, 56, 54, 49, 55, 48, 57, 50, 58,
+	52, 53, 59, 40,
+};
+
+struct gpio_bank {
+	char		*uid; /* acpi _UID */
+	int		ngpio;
+	unsigned	*to_pad;
+};
+
+static struct gpio_bank byt_banks[] = {
+	{
+		.uid = "1",
+		.ngpio = BYT_NGPIO_SCORE,
+		.to_pad = score_gpio_to_pad,
+	},
+	{
+		.uid = "2",
+		.ngpio = BYT_NGPIO_NCORE,
+		.to_pad = ncore_gpio_to_pad,
+	},
+	{
+		.uid = "3",
+		.ngpio = BYT_NGPIO_SUS,
+		.to_pad = sus_gpio_to_pad,
+	},
+	{
+	},
+};
+
+struct byt_gpio {
+	struct gpio_chip	chip;
+	struct irq_domain	*domain;
+	struct platform_device	*pdev;
+	spinlock_t		lock;
+	void __iomem		*reg_base;
+	unsigned		*gpio_to_pad;
+};
+
+static void __iomem *byt_gpio_reg(struct gpio_chip *chip, unsigned offset,
+				 int reg)
+{
+	struct byt_gpio *vg = container_of(chip, struct byt_gpio, chip);
+	u32 reg_offset;
+	void __iomem *ptr;
+
+	if (reg == BYT_INT_STAT_REG)
+		reg_offset = (offset / 32) * 4;
+	else
+		reg_offset = vg->gpio_to_pad[offset] * 16;
+
+	ptr = (void __iomem *) (vg->reg_base + reg_offset + reg);
+	return ptr;
+}
+
+static int byt_gpio_request(struct gpio_chip *chip, unsigned offset)
+{
+	struct byt_gpio *vg = container_of(chip, struct byt_gpio, chip);
+
+	pm_runtime_get(&vg->pdev->dev);
+
+	return 0;
+}
+
+static void byt_gpio_free(struct gpio_chip *chip, unsigned offset)
+{
+	struct byt_gpio *vg = container_of(chip, struct byt_gpio, chip);
+	void __iomem *reg = byt_gpio_reg(&vg->chip, offset, BYT_CONF0_REG);
+	u32 value;
+
+	/* clear interrupt triggering */
+	value = readl(reg);
+	value &= ~(BYT_TRIG_POS | BYT_TRIG_NEG | BYT_TRIG_LVL);
+	writel(value, reg);
+
+	pm_runtime_put(&vg->pdev->dev);
+}
+
+static int byt_irq_type(struct irq_data *d, unsigned type)
+{
+	struct byt_gpio *vg = irq_data_get_irq_chip_data(d);
+	u32 offset = irqd_to_hwirq(d);
+	u32 value;
+	unsigned long flags;
+	void __iomem *reg = byt_gpio_reg(&vg->chip, offset, BYT_CONF0_REG);
+
+	if (offset >= vg->chip.ngpio)
+		return -EINVAL;
+
+	spin_lock_irqsave(&vg->lock, flags);
+	value = readl(reg);
+
+	/* For level trigges the BYT_TRIG_POS and BYT_TRIG_NEG bits
+	 * are used to indicate high and low level triggering
+	 */
+	value &= ~(BYT_TRIG_POS | BYT_TRIG_NEG | BYT_TRIG_LVL);
+
+	switch (type) {
+	case IRQ_TYPE_LEVEL_HIGH:
+		value |= BYT_TRIG_LVL;
+	case IRQ_TYPE_EDGE_RISING:
+		value |= BYT_TRIG_POS;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		value |= BYT_TRIG_LVL;
+	case IRQ_TYPE_EDGE_FALLING:
+		value |= BYT_TRIG_NEG;
+		break;
+	case IRQ_TYPE_EDGE_BOTH:
+		value |= (BYT_TRIG_NEG | BYT_TRIG_POS);
+		break;
+	}
+	writel(value, reg);
+
+	spin_unlock_irqrestore(&vg->lock, flags);
+
+	return 0;
+}
+
+static int byt_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+	void __iomem *reg = byt_gpio_reg(chip, offset, BYT_VAL_REG);
+	return readl(reg) & BYT_LEVEL;
+}
+
+static void byt_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct byt_gpio *vg = container_of(chip, struct byt_gpio, chip);
+	void __iomem *reg = byt_gpio_reg(chip, offset, BYT_VAL_REG);
+	unsigned long flags;
+	u32 old_val;
+
+	spin_lock_irqsave(&vg->lock, flags);
+
+	old_val = readl(reg);
+
+	if (value)
+		writel(old_val | BYT_LEVEL, reg);
+	else
+		writel(old_val & ~BYT_LEVEL, reg);
+
+	spin_unlock_irqrestore(&vg->lock, flags);
+}
+
+static int byt_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+	struct byt_gpio *vg = container_of(chip, struct byt_gpio, chip);
+	void __iomem *reg = byt_gpio_reg(chip, offset, BYT_VAL_REG);
+	unsigned long flags;
+	u32 value;
+
+	spin_lock_irqsave(&vg->lock, flags);
+
+	value = readl(reg) | BYT_DIR_MASK;
+	value = value & (~BYT_INPUT_EN); /* active low */
+	writel(value, reg);
+
+	spin_unlock_irqrestore(&vg->lock, flags);
+
+	return 0;
+}
+
+static int byt_gpio_direction_output(struct gpio_chip *chip,
+				     unsigned gpio, int value)
+{
+	struct byt_gpio *vg = container_of(chip, struct byt_gpio, chip);
+	void __iomem *reg = byt_gpio_reg(chip, gpio, BYT_VAL_REG);
+	unsigned long flags;
+	u32 reg_val;
+
+	spin_lock_irqsave(&vg->lock, flags);
+
+	reg_val = readl(reg) | (BYT_DIR_MASK | !!value);
+	reg_val &= ~(BYT_OUTPUT_EN | !value);
+	writel(reg_val, reg);
+
+	spin_unlock_irqrestore(&vg->lock, flags);
+
+	return 0;
+}
+
+static void byt_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
+{
+	struct byt_gpio *vg = container_of(chip, struct byt_gpio, chip);
+	int i;
+	unsigned long flags;
+	u32 conf0, val, offs;
+
+	spin_lock_irqsave(&vg->lock, flags);
+
+	for (i = 0; i < vg->chip.ngpio; i++) {
+		offs = vg->gpio_to_pad[i] * 16;
+		conf0 = readl(vg->reg_base + offs + BYT_CONF0_REG);
+		val = readl(vg->reg_base + offs + BYT_VAL_REG);
+
+		seq_printf(s,
+			   " gpio-%-3d %s %s %s pad-%-3d offset:0x%03x mux:%d %s %s %s\n",
+			   i,
+			   val & BYT_INPUT_EN ? "  " : "in",
+			   val & BYT_OUTPUT_EN ? "   " : "out",
+			   val & BYT_LEVEL ? "hi" : "lo",
+			   vg->gpio_to_pad[i], offs,
+			   conf0 & 0x7,
+			   conf0 & BYT_TRIG_NEG ? "fall" : "",
+			   conf0 & BYT_TRIG_POS ? "rise" : "",
+			   conf0 & BYT_TRIG_LVL ? "lvl " : "");
+
+	}
+	spin_unlock_irqrestore(&vg->lock, flags);
+}
+
+static int byt_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
+{
+	struct byt_gpio *vg = container_of(chip, struct byt_gpio, chip);
+	return irq_create_mapping(vg->domain, offset);
+}
+
+static void byt_gpio_irq_handler(unsigned irq, struct irq_desc *desc)
+{
+	struct irq_data *data = irq_desc_get_irq_data(desc);
+	struct byt_gpio *vg = irq_data_get_irq_handler_data(data);
+	struct irq_chip *chip = irq_data_get_irq_chip(data);
+	u32 base, pin, mask;
+	void __iomem *reg;
+	u32 pending;
+	unsigned virq;
+	int looplimit = 0;
+
+	/* check from GPIO controller which pin triggered the interrupt */
+	for (base = 0; base < vg->chip.ngpio; base += 32) {
+
+		reg = byt_gpio_reg(&vg->chip, base, BYT_INT_STAT_REG);
+
+		while ((pending = readl(reg))) {
+			pin = __ffs(pending);
+			mask = BIT(pin);
+			/* Clear before handling so we can't lose an edge */
+			writel(mask, reg);
+
+			virq = irq_find_mapping(vg->domain, base + pin);
+			generic_handle_irq(virq);
+
+			/* In case bios or user sets triggering incorretly a pin
+			 * might remain in "interrupt triggered" state.
+			 */
+			if (looplimit++ > 32) {
+				dev_err(&vg->pdev->dev,
+					"Gpio %d interrupt flood, disabling\n",
+					base + pin);
+
+				reg = byt_gpio_reg(&vg->chip, base + pin,
+						   BYT_CONF0_REG);
+				mask = readl(reg);
+				mask &= ~(BYT_TRIG_NEG | BYT_TRIG_POS |
+					  BYT_TRIG_LVL);
+				writel(mask, reg);
+				mask = readl(reg); /* flush */
+				break;
+			}
+		}
+	}
+	chip->irq_eoi(data);
+}
+
+static void byt_irq_unmask(struct irq_data *d)
+{
+}
+
+static void byt_irq_mask(struct irq_data *d)
+{
+}
+
+static struct irq_chip byt_irqchip = {
+	.name = "BYT-GPIO",
+	.irq_mask = byt_irq_mask,
+	.irq_unmask = byt_irq_unmask,
+	.irq_set_type = byt_irq_type,
+};
+
+static void byt_gpio_irq_init_hw(struct byt_gpio *vg)
+{
+	void __iomem *reg;
+	u32 base, value;
+
+	/* clear interrupt status trigger registers */
+	for (base = 0; base < vg->chip.ngpio; base += 32) {
+		reg = byt_gpio_reg(&vg->chip, base, BYT_INT_STAT_REG);
+		writel(0xffffffff, reg);
+		/* make sure trigger bits are cleared, if not then a pin
+		   might be misconfigured in bios */
+		value = readl(reg);
+		if (value)
+			dev_err(&vg->pdev->dev,
+				"GPIO interrupt flood, pins misconfigured\n");
+	}
+}
+
+static int byt_gpio_irq_map(struct irq_domain *d, unsigned int virq,
+			    irq_hw_number_t hw)
+{
+	struct byt_gpio *vg = d->host_data;
+
+	irq_set_chip_and_handler_name(virq, &byt_irqchip, handle_simple_irq,
+				      "demux");
+	irq_set_chip_data(virq, vg);
+	irq_set_irq_type(virq, IRQ_TYPE_NONE);
+
+	return 0;
+}
+
+static const struct irq_domain_ops byt_gpio_irq_ops = {
+	.map = byt_gpio_irq_map,
+};
+
+static int byt_gpio_probe(struct platform_device *pdev)
+{
+	struct byt_gpio *vg;
+	struct gpio_chip *gc;
+	struct resource *mem_rc, *irq_rc;
+	struct device *dev = &pdev->dev;
+	struct acpi_device *acpi_dev;
+	struct gpio_bank *bank;
+	acpi_handle handle = ACPI_HANDLE(dev);
+	unsigned hwirq;
+	int ret;
+
+	if (acpi_bus_get_device(handle, &acpi_dev))
+		return -ENODEV;
+
+	vg = devm_kzalloc(dev, sizeof(struct byt_gpio), GFP_KERNEL);
+	if (!vg) {
+		dev_err(&pdev->dev, "can't allocate byt_gpio chip data\n");
+		return -ENOMEM;
+	}
+
+	for (bank = byt_banks; bank->uid; bank++) {
+		if (!strcmp(acpi_dev->pnp.unique_id, bank->uid)) {
+			vg->chip.ngpio = bank->ngpio;
+			vg->gpio_to_pad = bank->to_pad;
+			break;
+		}
+	}
+
+	if (!vg->chip.ngpio || !vg->gpio_to_pad)
+		return -ENODEV;
+
+	vg->pdev = pdev;
+	platform_set_drvdata(pdev, vg);
+
+	mem_rc = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	vg->reg_base = devm_ioremap_resource(dev, mem_rc);
+	if (IS_ERR(vg->reg_base))
+		return PTR_ERR(vg->reg_base);
+
+	spin_lock_init(&vg->lock);
+
+	gc = &vg->chip;
+	gc->label = dev_name(&pdev->dev);
+	gc->owner = THIS_MODULE;
+	gc->request = byt_gpio_request;
+	gc->free = byt_gpio_free;
+	gc->direction_input = byt_gpio_direction_input;
+	gc->direction_output = byt_gpio_direction_output;
+	gc->get = byt_gpio_get;
+	gc->set = byt_gpio_set;
+	gc->dbg_show = byt_gpio_dbg_show;
+	gc->base = -1;
+	gc->can_sleep = 0;
+	gc->dev = dev;
+
+	ret = gpiochip_add(gc);
+	if (ret) {
+		dev_err(&pdev->dev, "failed adding byt-gpio chip\n");
+		return ret;
+	}
+
+	/* set up interrupts  */
+	irq_rc = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (irq_rc && irq_rc->start) {
+		hwirq = irq_rc->start;
+		gc->to_irq = byt_gpio_to_irq;
+
+		vg->domain = irq_domain_add_linear(NULL, gc->ngpio,
+						   &byt_gpio_irq_ops, vg);
+		if (!vg->domain)
+			return -ENXIO;
+
+		byt_gpio_irq_init_hw(vg);
+
+		irq_set_handler_data(hwirq, vg);
+		irq_set_chained_handler(hwirq, byt_gpio_irq_handler);
+
+		/* Register interrupt handlers for gpio signaled acpi events */
+		acpi_gpiochip_request_interrupts(gc);
+	}
+
+	pm_runtime_enable(dev);
+
+	return 0;
+}
+
+static int byt_gpio_runtime_suspend(struct device *dev)
+{
+	return 0;
+}
+
+static int byt_gpio_runtime_resume(struct device *dev)
+{
+	return 0;
+}
+
+static const struct dev_pm_ops byt_gpio_pm_ops = {
+	.runtime_suspend = byt_gpio_runtime_suspend,
+	.runtime_resume = byt_gpio_runtime_resume,
+};
+
+static const struct acpi_device_id byt_gpio_acpi_match[] = {
+	{ "INT33B2", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, byt_gpio_acpi_match);
+
+static int byt_gpio_remove(struct platform_device *pdev)
+{
+	struct byt_gpio *vg = platform_get_drvdata(pdev);
+	int err;
+	pm_runtime_disable(&pdev->dev);
+	err = gpiochip_remove(&vg->chip);
+	if (err)
+		dev_warn(&pdev->dev, "failed to remove gpio_chip.\n");
+
+	return 0;
+}
+
+static struct platform_driver byt_gpio_driver = {
+	.probe          = byt_gpio_probe,
+	.remove         = byt_gpio_remove,
+	.driver         = {
+		.name   = "byt_gpio",
+		.owner  = THIS_MODULE,
+		.pm	= &byt_gpio_pm_ops,
+		.acpi_match_table = ACPI_PTR(byt_gpio_acpi_match),
+	},
+};
+
+static int __init byt_gpio_init(void)
+{
+	return platform_driver_register(&byt_gpio_driver);
+}
+
+subsys_initcall(byt_gpio_init);
-- 
1.7.4.1

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