powerpc/5200: Rework GPT driver to also be an IRQ controller

This patch adds IRQ controller support to the MPC5200 General
Purpose Timer (GPT) device driver.  With this patch the mpc5200-gpt
driver supports both GPIO and IRQ functions.

The GPT driver was contained within the mpc52xx_gpio.c file, but this
patch moves it out into a new file (mpc52xx_gpt.c) since it has more
than just GPIO functionality now and it was only grouped with the
mpc52xx-gpio drivers as a matter of convenience before.  Also, this
driver will most likely get extended again to also provide support
for the timer function.

Implementation note: Alternately, I could have tried to implement
the IRQ support as a separate driver and left the GPIO portion alone.
However, multiple functions of this device (ie. GPIO input+interrupt
controller, or timer+GPIO) can be active at the same time and the
registers are shared so it is safer to contain all functionality
within a single driver.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>

1 files changed, 435 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/52xx/mpc52xx_gpt.c b/arch/powerpc/platforms/52xx/mpc52xx_gpt.c
new file mode 100644
index 0000000..cb038dc
--- /dev/null
+++ b/arch/powerpc/platforms/52xx/mpc52xx_gpt.c
@@ -0,0 +1,435 @@
+/*
+ * MPC5200 General Purpose Timer device driver
+ *
+ * Copyright (c) 2009 Secret Lab Technologies Ltd.
+ * Copyright (c) 2008 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ *
+ * This file is a driver for the the General Purpose Timer (gpt) devices
+ * found on the MPC5200 SoC.  Each timer has an IO pin which can be used
+ * for GPIO or can be used to raise interrupts.  The timer function can
+ * be used independently from the IO pin, or it can be used to control
+ * output signals or measure input signals.
+ *
+ * This driver supports the GPIO and IRQ controller functions of the GPT
+ * device.  Timer functions are not yet supported, nor is the watchdog
+ * timer.
+ *
+ * To use the GPIO function, the following two properties must be added
+ * to the device tree node for the gpt device (typically in the .dts file
+ * for the board):
+ * 	gpio-controller;
+ * 	#gpio-cells = < 2 >;
+ * This driver will register the GPIO pin if it finds the gpio-controller
+ * property in the device tree.
+ *
+ * To use the IRQ controller function, the following two properties must
+ * be added to the device tree node for the gpt device:
+ * 	interrupt-controller;
+ * 	#interrupt-cells = < 1 >;
+ * The IRQ controller binding only uses one cell to specify the interrupt,
+ * and the IRQ flags are encoded in the cell.  A cell is not used to encode
+ * the IRQ number because the GPT only has a single IRQ source.  For flags,
+ * a value of '1' means rising edge sensitive and '2' means falling edge.
+ *
+ * The GPIO and the IRQ controller functions can be used at the same time,
+ * but in this use case the IO line will only work as an input.  Trying to
+ * use it as a GPIO output will not work.
+ *
+ * When using the GPIO line as an output, it can either be driven as normal
+ * IO, or it can be an Open Collector (OC) output.  At the moment it is the
+ * responsibility of either the bootloader or the platform setup code to set
+ * the output mode.  This driver does not change the output mode setting.
+ */
+
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/of_gpio.h>
+#include <linux/kernel.h>
+#include <asm/mpc52xx.h>
+
+MODULE_DESCRIPTION("Freescale MPC52xx gpt driver");
+MODULE_AUTHOR("Sascha Hauer, Grant Likely");
+MODULE_LICENSE("GPL");
+
+/**
+ * struct mpc52xx_gpt - Private data structure for MPC52xx GPT driver
+ * @dev: pointer to device structure
+ * @regs: virtual address of GPT registers
+ * @lock: spinlock to coordinate between different functions.
+ * @of_gc: of_gpio_chip instance structure; used when GPIO is enabled
+ * @irqhost: Pointer to irq_host instance; used when IRQ mode is supported
+ */
+struct mpc52xx_gpt_priv {
+	struct device *dev;
+	struct mpc52xx_gpt __iomem *regs;
+	spinlock_t lock;
+	struct irq_host *irqhost;
+
+#if defined(CONFIG_GPIOLIB)
+	struct of_gpio_chip of_gc;
+#endif
+};
+
+#define MPC52xx_GPT_MODE_MS_MASK	(0x07)
+#define MPC52xx_GPT_MODE_MS_IC		(0x01)
+#define MPC52xx_GPT_MODE_MS_OC		(0x02)
+#define MPC52xx_GPT_MODE_MS_PWM		(0x03)
+#define MPC52xx_GPT_MODE_MS_GPIO	(0x04)
+
+#define MPC52xx_GPT_MODE_GPIO_MASK	(0x30)
+#define MPC52xx_GPT_MODE_GPIO_OUT_LOW	(0x20)
+#define MPC52xx_GPT_MODE_GPIO_OUT_HIGH	(0x30)
+
+#define MPC52xx_GPT_MODE_IRQ_EN		(0x0100)
+
+#define MPC52xx_GPT_MODE_ICT_MASK	(0x030000)
+#define MPC52xx_GPT_MODE_ICT_RISING	(0x010000)
+#define MPC52xx_GPT_MODE_ICT_FALLING	(0x020000)
+#define MPC52xx_GPT_MODE_ICT_TOGGLE	(0x030000)
+
+#define MPC52xx_GPT_STATUS_IRQMASK	(0x000f)
+
+/* ---------------------------------------------------------------------
+ * Cascaded interrupt controller hooks
+ */
+
+static void mpc52xx_gpt_irq_unmask(unsigned int virq)
+{
+	struct mpc52xx_gpt_priv *gpt = get_irq_chip_data(virq);
+	unsigned long flags;
+
+	spin_lock_irqsave(&gpt->lock, flags);
+	setbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_IRQ_EN);
+	spin_unlock_irqrestore(&gpt->lock, flags);
+}
+
+static void mpc52xx_gpt_irq_mask(unsigned int virq)
+{
+	struct mpc52xx_gpt_priv *gpt = get_irq_chip_data(virq);
+	unsigned long flags;
+
+	spin_lock_irqsave(&gpt->lock, flags);
+	clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_IRQ_EN);
+	spin_unlock_irqrestore(&gpt->lock, flags);
+}
+
+static void mpc52xx_gpt_irq_ack(unsigned int virq)
+{
+	struct mpc52xx_gpt_priv *gpt = get_irq_chip_data(virq);
+
+	out_be32(&gpt->regs->status, MPC52xx_GPT_STATUS_IRQMASK);
+}
+
+static int mpc52xx_gpt_irq_set_type(unsigned int virq, unsigned int flow_type)
+{
+	struct mpc52xx_gpt_priv *gpt = get_irq_chip_data(virq);
+	unsigned long flags;
+	u32 reg;
+
+	dev_dbg(gpt->dev, "%s: virq=%i type=%x\n", __func__, virq, flow_type);
+
+	spin_lock_irqsave(&gpt->lock, flags);
+	reg = in_be32(&gpt->regs->mode) & ~MPC52xx_GPT_MODE_ICT_MASK;
+	if (flow_type & IRQF_TRIGGER_RISING)
+		reg |= MPC52xx_GPT_MODE_ICT_RISING;
+	if (flow_type & IRQF_TRIGGER_FALLING)
+		reg |= MPC52xx_GPT_MODE_ICT_FALLING;
+	out_be32(&gpt->regs->mode, reg);
+	spin_unlock_irqrestore(&gpt->lock, flags);
+
+	return 0;
+}
+
+static struct irq_chip mpc52xx_gpt_irq_chip = {
+	.typename = "MPC52xx GPT",
+	.unmask = mpc52xx_gpt_irq_unmask,
+	.mask = mpc52xx_gpt_irq_mask,
+	.ack = mpc52xx_gpt_irq_ack,
+	.set_type = mpc52xx_gpt_irq_set_type,
+};
+
+void mpc52xx_gpt_irq_cascade(unsigned int virq, struct irq_desc *desc)
+{
+	struct mpc52xx_gpt_priv *gpt = get_irq_data(virq);
+	int sub_virq;
+	u32 status;
+
+	status = in_be32(&gpt->regs->status) & MPC52xx_GPT_STATUS_IRQMASK;
+	if (status) {
+		sub_virq = irq_linear_revmap(gpt->irqhost, 0);
+		generic_handle_irq(sub_virq);
+	}
+}
+
+static int mpc52xx_gpt_irq_map(struct irq_host *h, unsigned int virq,
+			       irq_hw_number_t hw)
+{
+	struct mpc52xx_gpt_priv *gpt = h->host_data;
+
+	dev_dbg(gpt->dev, "%s: h=%p, virq=%i\n", __func__, h, virq);
+	set_irq_chip_data(virq, gpt);
+	set_irq_chip_and_handler(virq, &mpc52xx_gpt_irq_chip, handle_edge_irq);
+
+	return 0;
+}
+
+static int mpc52xx_gpt_irq_xlate(struct irq_host *h, struct device_node *ct,
+				 u32 *intspec, unsigned int intsize,
+				 irq_hw_number_t *out_hwirq,
+				 unsigned int *out_flags)
+{
+	struct mpc52xx_gpt_priv *gpt = h->host_data;
+
+	dev_dbg(gpt->dev, "%s: flags=%i\n", __func__, intspec[0]);
+
+	if ((intsize < 1) || (intspec[0] < 1) || (intspec[0] > 3)) {
+		dev_err(gpt->dev, "bad irq specifier in %s\n", ct->full_name);
+		return -EINVAL;
+	}
+
+	*out_hwirq = 0; /* The GPT only has 1 IRQ line */
+	*out_flags = intspec[0];
+
+	return 0;
+}
+
+static struct irq_host_ops mpc52xx_gpt_irq_ops = {
+	.map = mpc52xx_gpt_irq_map,
+	.xlate = mpc52xx_gpt_irq_xlate,
+};
+
+static void
+mpc52xx_gpt_irq_setup(struct mpc52xx_gpt_priv *gpt, struct device_node *node)
+{
+	int cascade_virq;
+	unsigned long flags;
+
+	/* Only setup cascaded IRQ if device tree claims the GPT is
+	 * an interrupt controller */
+	if (!of_find_property(node, "interrupt-controller", NULL))
+		return;
+
+	cascade_virq = irq_of_parse_and_map(node, 0);
+
+	gpt->irqhost = irq_alloc_host(node, IRQ_HOST_MAP_LINEAR, 1,
+				      &mpc52xx_gpt_irq_ops, -1);
+	if (!gpt->irqhost) {
+		dev_err(gpt->dev, "irq_alloc_host() failed\n");
+		return;
+	}
+
+	gpt->irqhost->host_data = gpt;
+
+	set_irq_data(cascade_virq, gpt);
+	set_irq_chained_handler(cascade_virq, mpc52xx_gpt_irq_cascade);
+
+	/* Set to Input Capture mode */
+	spin_lock_irqsave(&gpt->lock, flags);
+	clrsetbits_be32(&gpt->regs->mode, MPC52xx_GPT_MODE_MS_MASK,
+			MPC52xx_GPT_MODE_MS_IC);
+	spin_unlock_irqrestore(&gpt->lock, flags);
+
+	dev_dbg(gpt->dev, "%s() complete. virq=%i\n", __func__, cascade_virq);
+}
+
+
+/* ---------------------------------------------------------------------
+ * GPIOLIB hooks
+ */
+#if defined(CONFIG_GPIOLIB)
+static inline struct mpc52xx_gpt_priv *gc_to_mpc52xx_gpt(struct gpio_chip *gc)
+{
+	return container_of(to_of_gpio_chip(gc), struct mpc52xx_gpt_priv,of_gc);
+}
+
+static int mpc52xx_gpt_gpio_get(struct gpio_chip *gc, unsigned int gpio)
+{
+	struct mpc52xx_gpt_priv *gpt = gc_to_mpc52xx_gpt(gc);
+
+	return (in_be32(&gpt->regs->status) >> 8) & 1;
+}
+
+static void
+mpc52xx_gpt_gpio_set(struct gpio_chip *gc, unsigned int gpio, int v)
+{
+	struct mpc52xx_gpt_priv *gpt = gc_to_mpc52xx_gpt(gc);
+	unsigned long flags;
+	u32 r;
+
+	dev_dbg(gpt->dev, "%s: gpio:%d v:%d\n", __func__, gpio, v);
+	r = v ? MPC52xx_GPT_MODE_GPIO_OUT_HIGH : MPC52xx_GPT_MODE_GPIO_OUT_LOW;
+
+	spin_lock_irqsave(&gpt->lock, flags);
+	clrsetbits_be32(&gpt->regs->mode, MPC52xx_GPT_MODE_GPIO_MASK, r);
+	spin_unlock_irqrestore(&gpt->lock, flags);
+}
+
+static int mpc52xx_gpt_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
+{
+	struct mpc52xx_gpt_priv *gpt = gc_to_mpc52xx_gpt(gc);
+	unsigned long flags;
+
+	dev_dbg(gpt->dev, "%s: gpio:%d\n", __func__, gpio);
+
+	spin_lock_irqsave(&gpt->lock, flags);
+	clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_GPIO_MASK);
+	spin_unlock_irqrestore(&gpt->lock, flags);
+
+	return 0;
+}
+
+static int
+mpc52xx_gpt_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+	mpc52xx_gpt_gpio_set(gc, gpio, val);
+	return 0;
+}
+
+static void
+mpc52xx_gpt_gpio_setup(struct mpc52xx_gpt_priv *gpt, struct device_node *node)
+{
+	int rc;
+
+	/* Only setup GPIO if the device tree claims the GPT is
+	 * a GPIO controller */
+	if (!of_find_property(node, "gpio-controller", NULL))
+		return;
+
+	gpt->of_gc.gc.label = kstrdup(node->full_name, GFP_KERNEL);
+	if (!gpt->of_gc.gc.label) {
+		dev_err(gpt->dev, "out of memory\n");
+		return;
+	}
+
+	gpt->of_gc.gpio_cells = 2;
+	gpt->of_gc.gc.ngpio = 1;
+	gpt->of_gc.gc.direction_input  = mpc52xx_gpt_gpio_dir_in;
+	gpt->of_gc.gc.direction_output = mpc52xx_gpt_gpio_dir_out;
+	gpt->of_gc.gc.get = mpc52xx_gpt_gpio_get;
+	gpt->of_gc.gc.set = mpc52xx_gpt_gpio_set;
+	gpt->of_gc.gc.base = -1;
+	gpt->of_gc.xlate = of_gpio_simple_xlate;
+	node->data = &gpt->of_gc;
+	of_node_get(node);
+
+	/* Setup external pin in GPIO mode */
+	clrsetbits_be32(&gpt->regs->mode, MPC52xx_GPT_MODE_MS_MASK,
+			MPC52xx_GPT_MODE_MS_GPIO);
+
+	rc = gpiochip_add(&gpt->of_gc.gc);
+	if (rc)
+		dev_err(gpt->dev, "gpiochip_add() failed; rc=%i\n", rc);
+
+	dev_dbg(gpt->dev, "%s() complete.\n", __func__);
+}
+#else /* defined(CONFIG_GPIOLIB) */
+static void
+mpc52xx_gpt_gpio_setup(struct mpc52xx_gpt_priv *p, struct device_node *np) { }
+#endif /* defined(CONFIG_GPIOLIB) */
+
+/***********************************************************************
+ * SYSFS attributes
+ */
+#if defined(CONFIG_SYSFS)
+static ssize_t mpc52xx_gpt_show_regs(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct mpc52xx_gpt_priv *gpt = dev_get_drvdata(dev);
+	int i, len = 0;
+	u32 __iomem *regs = (void __iomem *) gpt->regs;
+
+	for (i = 0; i < 4; i++)
+		len += sprintf(buf + len, "%.8x ", in_be32(regs + i));
+	len += sprintf(buf + len, "\n");
+
+	return len;
+}
+
+static struct device_attribute mpc52xx_gpt_attrib[] = {
+	__ATTR(regs, S_IRUGO | S_IWUSR, mpc52xx_gpt_show_regs, NULL),
+};
+
+static void mpc52xx_gpt_create_attribs(struct mpc52xx_gpt_priv *gpt)
+{
+	int i, err = 0;
+
+	for (i = 0; i < ARRAY_SIZE(mpc52xx_gpt_attrib); i++) {
+		err = device_create_file(gpt->dev, &mpc52xx_gpt_attrib[i]);
+		if (err)
+			dev_err(gpt->dev, "error creating attribute %i\n", i);
+	}
+
+}
+
+#else /* defined(CONFIG_SYSFS) */
+static void mpc52xx_gpt_create_attribs(struct mpc52xx_gpt_priv *) { return 0; }
+#endif /* defined(CONFIG_SYSFS) */
+
+/* ---------------------------------------------------------------------
+ * of_platform bus binding code
+ */
+static int __devinit mpc52xx_gpt_probe(struct of_device *ofdev,
+				       const struct of_device_id *match)
+{
+	struct mpc52xx_gpt_priv *gpt;
+
+	gpt = kzalloc(sizeof *gpt, GFP_KERNEL);
+	if (!gpt)
+		return -ENOMEM;
+
+	spin_lock_init(&gpt->lock);
+	gpt->dev = &ofdev->dev;
+	gpt->regs = of_iomap(ofdev->node, 0);
+	if (!gpt->regs) {
+		kfree(gpt);
+		return -ENOMEM;
+	}
+
+	dev_set_drvdata(&ofdev->dev, gpt);
+
+	mpc52xx_gpt_create_attribs(gpt);
+	mpc52xx_gpt_gpio_setup(gpt, ofdev->node);
+	mpc52xx_gpt_irq_setup(gpt, ofdev->node);
+
+	return 0;
+}
+
+static int mpc52xx_gpt_remove(struct of_device *ofdev)
+{
+	return -EBUSY;
+}
+
+static const struct of_device_id mpc52xx_gpt_match[] = {
+	{ .compatible = "fsl,mpc5200-gpt", },
+
+	/* Depreciated compatible values; don't use for new dts files */
+	{ .compatible = "fsl,mpc5200-gpt-gpio", },
+	{ .compatible = "mpc5200-gpt", },
+	{}
+};
+
+static struct of_platform_driver mpc52xx_gpt_driver = {
+	.name = "mpc52xx-gpt",
+	.match_table = mpc52xx_gpt_match,
+	.probe = mpc52xx_gpt_probe,
+	.remove = mpc52xx_gpt_remove,
+};
+
+static int __init mpc52xx_gpt_init(void)
+{
+	if (of_register_platform_driver(&mpc52xx_gpt_driver))
+		pr_err("error registering MPC52xx GPT driver\n");
+
+	return 0;
+}
+
+/* Make sure GPIOs and IRQs get set up before anyone tries to use them */
+subsys_initcall(mpc52xx_gpt_init);