gpio-tz1090-pdc: add TZ1090 PDC gpio driver

Add a GPIO driver for the low-power Powerdown Controller GPIOs in the
TZ1090 SoC.

The driver is instantiated by device tree and supports interrupts for
the SysWake GPIOs only.

Changes in v4:
 - fix typos in DT bindings compatible properties
 - reference Documentation/devicetree/bindings/gpio/gpio.txt in
   gpio-ranges description in DT bindings
 - fix gpio-ranges examples in DT bindings (it must now have 3 cells)

Changes in v3:
 - separated from irq-imgpdc and removed arch/metag changes to allow
   these patches to go upstream separately via the pinctrl[/gpio] trees
   (particularly the pinctrl drivers depend on the new pinconf DT
   bindings).
 - some s/unsigned/unsigned int/.
 - gpio-tz1090*: refer to <dt-bindings/gpio/gpio.h> and
   <dt-bindings/interrupt-controller/irq.h> flags in bindings.
 - gpio-tz1090*: move initcall from postcore to subsys.

Changes in v2:
 - gpio-tz1090-pdc: remove references to Linux flags in dt bindings
 - gpio-tz1090-pdc: make use of BIT() from linux/bitops.h
 - gpio-tz1090-pdc: make register accessors inline to match pinctrl
 - gpio-tz1090-pdc: update gpio-ranges to use 3 cells after recent ABI
   breakage

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Rob Landley <rob@landley.net>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-doc@vger.kernel.org
Cc: devicetree-discuss@lists.ozlabs.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 243 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-tz1090-pdc.c b/drivers/gpio/gpio-tz1090-pdc.c
new file mode 100644
index 000000000000..f512da299b3d
--- /dev/null
+++ b/drivers/gpio/gpio-tz1090-pdc.c
@@ -0,0 +1,243 @@
+/*
+ * Toumaz Xenif TZ1090 PDC GPIO handling.
+ *
+ * Copyright (C) 2012-2013 Imagination Technologies Ltd.
+ *
+ * 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.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_irq.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/syscore_ops.h>
+#include <asm/global_lock.h>
+
+/* Register offsets from SOC_GPIO_CONTROL0 */
+#define REG_SOC_GPIO_CONTROL0	0x00
+#define REG_SOC_GPIO_CONTROL1	0x04
+#define REG_SOC_GPIO_CONTROL2	0x08
+#define REG_SOC_GPIO_CONTROL3	0x0c
+#define REG_SOC_GPIO_STATUS	0x80
+
+/* PDC GPIOs go after normal GPIOs */
+#define GPIO_PDC_BASE		90
+#define GPIO_PDC_NGPIO		7
+
+/* Out of PDC gpios, only syswakes have irqs */
+#define GPIO_PDC_IRQ_FIRST	2
+#define GPIO_PDC_NIRQ		3
+
+/**
+ * struct tz1090_pdc_gpio - GPIO bank private data
+ * @chip:	Generic GPIO chip for GPIO bank
+ * @reg:	Base of registers, offset for this GPIO bank
+ * @irq:	IRQ numbers for Syswake GPIOs
+ *
+ * This is the main private data for the PDC GPIO driver. It encapsulates a
+ * gpio_chip, and the callbacks for the gpio_chip can access the private data
+ * with the to_pdc() macro below.
+ */
+struct tz1090_pdc_gpio {
+	struct gpio_chip chip;
+	void __iomem *reg;
+	int irq[GPIO_PDC_NIRQ];
+};
+#define to_pdc(c)	container_of(c, struct tz1090_pdc_gpio, chip)
+
+/* Register accesses into the PDC MMIO area */
+
+static inline void pdc_write(struct tz1090_pdc_gpio *priv, unsigned int reg_offs,
+		      unsigned int data)
+{
+	writel(data, priv->reg + reg_offs);
+}
+
+static inline unsigned int pdc_read(struct tz1090_pdc_gpio *priv,
+			     unsigned int reg_offs)
+{
+	return readl(priv->reg + reg_offs);
+}
+
+/* Generic GPIO interface */
+
+static int tz1090_pdc_gpio_direction_input(struct gpio_chip *chip,
+					   unsigned int offset)
+{
+	struct tz1090_pdc_gpio *priv = to_pdc(chip);
+	u32 value;
+	int lstat;
+
+	__global_lock2(lstat);
+	value = pdc_read(priv, REG_SOC_GPIO_CONTROL1);
+	value |= BIT(offset);
+	pdc_write(priv, REG_SOC_GPIO_CONTROL1, value);
+	__global_unlock2(lstat);
+
+	return 0;
+}
+
+static int tz1090_pdc_gpio_direction_output(struct gpio_chip *chip,
+					    unsigned int offset,
+					    int output_value)
+{
+	struct tz1090_pdc_gpio *priv = to_pdc(chip);
+	u32 value;
+	int lstat;
+
+	__global_lock2(lstat);
+	/* EXT_POWER doesn't seem to have an output value bit */
+	if (offset < 6) {
+		value = pdc_read(priv, REG_SOC_GPIO_CONTROL0);
+		if (output_value)
+			value |= BIT(offset);
+		else
+			value &= ~BIT(offset);
+		pdc_write(priv, REG_SOC_GPIO_CONTROL0, value);
+	}
+
+	value = pdc_read(priv, REG_SOC_GPIO_CONTROL1);
+	value &= ~BIT(offset);
+	pdc_write(priv, REG_SOC_GPIO_CONTROL1, value);
+	__global_unlock2(lstat);
+
+	return 0;
+}
+
+static int tz1090_pdc_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+	struct tz1090_pdc_gpio *priv = to_pdc(chip);
+	return pdc_read(priv, REG_SOC_GPIO_STATUS) & BIT(offset);
+}
+
+static void tz1090_pdc_gpio_set(struct gpio_chip *chip, unsigned int offset,
+				int output_value)
+{
+	struct tz1090_pdc_gpio *priv = to_pdc(chip);
+	u32 value;
+	int lstat;
+
+	/* EXT_POWER doesn't seem to have an output value bit */
+	if (offset >= 6)
+		return;
+
+	__global_lock2(lstat);
+	value = pdc_read(priv, REG_SOC_GPIO_CONTROL0);
+	if (output_value)
+		value |= BIT(offset);
+	else
+		value &= ~BIT(offset);
+	pdc_write(priv, REG_SOC_GPIO_CONTROL0, value);
+	__global_unlock2(lstat);
+}
+
+static int tz1090_pdc_gpio_request(struct gpio_chip *chip, unsigned int offset)
+{
+	return pinctrl_request_gpio(chip->base + offset);
+}
+
+static void tz1090_pdc_gpio_free(struct gpio_chip *chip, unsigned int offset)
+{
+	pinctrl_free_gpio(chip->base + offset);
+}
+
+static int tz1090_pdc_gpio_to_irq(struct gpio_chip *chip, unsigned int offset)
+{
+	struct tz1090_pdc_gpio *priv = to_pdc(chip);
+	unsigned int syswake = offset - GPIO_PDC_IRQ_FIRST;
+	int irq;
+
+	/* only syswakes have irqs */
+	if (syswake >= GPIO_PDC_NIRQ)
+		return -EINVAL;
+
+	irq = priv->irq[syswake];
+	if (!irq)
+		return -EINVAL;
+
+	return irq;
+}
+
+static int tz1090_pdc_gpio_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct resource *res_regs;
+	struct tz1090_pdc_gpio *priv;
+	unsigned int i;
+
+	if (!np) {
+		dev_err(&pdev->dev, "must be instantiated via devicetree\n");
+		return -ENOENT;
+	}
+
+	res_regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res_regs) {
+		dev_err(&pdev->dev, "cannot find registers resource\n");
+		return -ENOENT;
+	}
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv) {
+		dev_err(&pdev->dev, "unable to allocate driver data\n");
+		return -ENOMEM;
+	}
+
+	/* Ioremap the registers */
+	priv->reg = devm_ioremap(&pdev->dev, res_regs->start,
+				 res_regs->end - res_regs->start);
+	if (!priv->reg) {
+		dev_err(&pdev->dev, "unable to ioremap registers\n");
+		return -ENOMEM;
+	}
+
+	/* Set up GPIO chip */
+	priv->chip.label		= "tz1090-pdc-gpio";
+	priv->chip.dev			= &pdev->dev;
+	priv->chip.direction_input	= tz1090_pdc_gpio_direction_input;
+	priv->chip.direction_output	= tz1090_pdc_gpio_direction_output;
+	priv->chip.get			= tz1090_pdc_gpio_get;
+	priv->chip.set			= tz1090_pdc_gpio_set;
+	priv->chip.free			= tz1090_pdc_gpio_free;
+	priv->chip.request		= tz1090_pdc_gpio_request;
+	priv->chip.to_irq		= tz1090_pdc_gpio_to_irq;
+	priv->chip.of_node		= np;
+
+	/* GPIO numbering */
+	priv->chip.base			= GPIO_PDC_BASE;
+	priv->chip.ngpio		= GPIO_PDC_NGPIO;
+
+	/* Map the syswake irqs */
+	for (i = 0; i < GPIO_PDC_NIRQ; ++i)
+		priv->irq[i] = irq_of_parse_and_map(np, i);
+
+	/* Add the GPIO bank */
+	gpiochip_add(&priv->chip);
+
+	return 0;
+}
+
+static struct of_device_id tz1090_pdc_gpio_of_match[] = {
+	{ .compatible = "img,tz1090-pdc-gpio" },
+	{ },
+};
+
+static struct platform_driver tz1090_pdc_gpio_driver = {
+	.driver = {
+		.name		= "tz1090-pdc-gpio",
+		.owner		= THIS_MODULE,
+		.of_match_table	= tz1090_pdc_gpio_of_match,
+	},
+	.probe		= tz1090_pdc_gpio_probe,
+};
+
+static int __init tz1090_pdc_gpio_init(void)
+{
+	return platform_driver_register(&tz1090_pdc_gpio_driver);
+}
+subsys_initcall(tz1090_pdc_gpio_init);