pinctrl: add Intel BayTrail GPIO/pinctrl support

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

Pins may be muxed to alternate function instead of gpio by firmware.
This driver does not touch the pin muxing and expect firmare
to set pin muxing and pullup/down properties properly.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

3 files changed, 556 insertions, 0 deletions

diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
index 269c0406dce4..e01976fb1175 100644
--- a/drivers/pinctrl/Kconfig
+++ b/drivers/pinctrl/Kconfig
@@ -58,6 +58,18 @@ config PINCTRL_AT91
 	help
 	  Say Y here to enable the at91 pinctrl driver
 
+config PINCTRL_BAYTRAIL
+	bool "Intel Baytrail GPIO pin control"
+	depends on GPIOLIB && 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 PINCTRL_BCM2835
 	bool
 	select PINMUX
diff --git a/drivers/pinctrl/Makefile b/drivers/pinctrl/Makefile
index ff38aca65689..9031afddb9ad 100644
--- a/drivers/pinctrl/Makefile
+++ b/drivers/pinctrl/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_PINCTRL_AB9540)	+= pinctrl-ab9540.o
 obj-$(CONFIG_PINCTRL_AB8505)	+= pinctrl-ab8505.o
 obj-$(CONFIG_PINCTRL_AT91)	+= pinctrl-at91.o
 obj-$(CONFIG_PINCTRL_BCM2835)	+= pinctrl-bcm2835.o
+obj-$(CONFIG_PINCTRL_BAYTRAIL)	+= pinctrl-baytrail.o
 obj-$(CONFIG_PINCTRL_IMX)	+= pinctrl-imx.o
 obj-$(CONFIG_PINCTRL_IMX35)	+= pinctrl-imx35.o
 obj-$(CONFIG_PINCTRL_IMX51)	+= pinctrl-imx51.o
diff --git a/drivers/pinctrl/pinctrl-baytrail.c b/drivers/pinctrl/pinctrl-baytrail.c
new file mode 100644
index 000000000000..e9d735dcebfb
--- /dev/null
+++ b/drivers/pinctrl/pinctrl-baytrail.c
@@ -0,0 +1,543 @@
+/*
+ * Pinctrl GPIO driver for Intel Baytrail
+ * Copyright (c) 2012-2013, Intel Corporation.
+ *
+ * Author: Mathias Nyman <mathias.nyman@linux.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>
+#include <linux/pinctrl/pinctrl.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
+ */
+
+/* score_pins[gpio_nr] = pad_nr */
+
+static unsigned const score_pins[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 const ncore_pins[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 const sus_pins[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,
+};
+
+static struct pinctrl_gpio_range byt_ranges[] = {
+	{
+		.name = "1", /* match with acpi _UID in probe */
+		.npins = BYT_NGPIO_SCORE,
+		.pins = score_pins,
+	},
+	{
+		.name = "2",
+		.npins = BYT_NGPIO_NCORE,
+		.pins = ncore_pins,
+	},
+	{
+		.name = "3",
+		.npins = BYT_NGPIO_SUS,
+		.pins = sus_pins,
+	},
+	{
+	},
+};
+
+struct byt_gpio {
+	struct gpio_chip		chip;
+	struct irq_domain		*domain;
+	struct platform_device		*pdev;
+	spinlock_t			lock;
+	void __iomem			*reg_base;
+	struct pinctrl_gpio_range	*range;
+};
+
+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->range->pins[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->range->pins[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->range->pins[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 error, 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 pinctrl_gpio_range *range;
+	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 (range = byt_ranges; range->name; range++) {
+		if (!strcmp(acpi_dev->pnp.unique_id, range->name)) {
+			vg->chip.ngpio = range->npins;
+			vg->range = range;
+			break;
+		}
+	}
+
+	if (!vg->chip.ngpio || !vg->range)
+		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);