gpio: Add STA2X11 GPIO block

This introduces 128 gpio bits (for each PCI device installed) with
working interrupt support.

Signed-off-by: Alessandro Rubini <[e-mail]>
Acked-by: Giancarlo Asnaghi <[e-mail]>
Cc: Alan Cox <[e-mail]>
Signed-off-by: Samuel Ortiz <[e-mail]>

drivers/gpio/Kconfig

···
 	help
 	  Say yes here to support the PXA GPIO device
 
+config GPIO_STA2X11
+	bool "STA2x11/ConneXt GPIO support"
+	depends on MFD_STA2X11
+	select GENERIC_IRQ_CHIP
+	help
+	  Say yes here to support the STA2x11/ConneXt GPIO device.
+	  The GPIO module has 128 GPIO pins with alternate functions.
+
 config GPIO_XILINX
 	bool "Xilinx GPIO support"
 	depends on PPC_OF || MICROBLAZE

drivers/gpio/Makefile

···
 obj-$(CONFIG_ARCH_SA1100)	+= gpio-sa1100.o
 obj-$(CONFIG_GPIO_SCH)		+= gpio-sch.o
 obj-$(CONFIG_GPIO_SODAVILLE)	+= gpio-sodaville.o
+obj-$(CONFIG_GPIO_STA2X11)	+= gpio-sta2x11.o
 obj-$(CONFIG_GPIO_STMPE)	+= gpio-stmpe.o
 obj-$(CONFIG_GPIO_SX150X)	+= gpio-sx150x.o
 obj-$(CONFIG_GPIO_TC3589X)	+= gpio-tc3589x.o

drivers/gpio/gpio-sta2x11.c

···
+/*
+ * STMicroelectronics ConneXt (STA2X11) GPIO driver
+ *
+ * Copyright 2012 ST Microelectronics (Alessandro Rubini)
+ * Based on gpio-ml-ioh.c, Copyright 2010 OKI Semiconductors Ltd.
+ * Also based on previous sta2x11 work, Copyright 2011 Wind River Systems, Inc.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/sta2x11-mfd.h>
+
+struct gsta_regs {
+	u32 dat;		/* 0x00 */
+	u32 dats;
+	u32 datc;
+	u32 pdis;
+	u32 dir;		/* 0x10 */
+	u32 dirs;
+	u32 dirc;
+	u32 unused_1c;
+	u32 afsela;		/* 0x20 */
+	u32 unused_24[7];
+	u32 rimsc;		/* 0x40 */
+	u32 fimsc;
+	u32 is;
+	u32 ic;
+};
+
+struct gsta_gpio {
+	spinlock_t			lock;
+	struct device			*dev;
+	void __iomem			*reg_base;
+	struct gsta_regs __iomem	*regs[GSTA_NR_BLOCKS];
+	struct gpio_chip		gpio;
+	int				irq_base;
+	/* FIXME: save the whole config here (AF, ...) */
+	unsigned			irq_type[GSTA_NR_GPIO];
+};
+
+static inline struct gsta_regs __iomem *__regs(struct gsta_gpio *chip, int nr)
+{
+	return chip->regs[nr / GSTA_GPIO_PER_BLOCK];
+}
+
+static inline u32 __bit(int nr)
+{
+	return 1U << (nr % GSTA_GPIO_PER_BLOCK);
+}
+
+/*
+ * gpio methods
+ */
+
+static void gsta_gpio_set(struct gpio_chip *gpio, unsigned nr, int val)
+{
+	struct gsta_gpio *chip = container_of(gpio, struct gsta_gpio, gpio);
+	struct gsta_regs __iomem *regs = __regs(chip, nr);
+	u32 bit = __bit(nr);
+
+	if (val)
+		writel(bit, &regs->dats);
+	else
+		writel(bit, &regs->datc);
+}
+
+static int gsta_gpio_get(struct gpio_chip *gpio, unsigned nr)
+{
+	struct gsta_gpio *chip = container_of(gpio, struct gsta_gpio, gpio);
+	struct gsta_regs __iomem *regs = __regs(chip, nr);
+	u32 bit = __bit(nr);
+
+	return readl(&regs->dat) & bit;
+}
+
+static int gsta_gpio_direction_output(struct gpio_chip *gpio, unsigned nr,
+				      int val)
+{
+	struct gsta_gpio *chip = container_of(gpio, struct gsta_gpio, gpio);
+	struct gsta_regs __iomem *regs = __regs(chip, nr);
+	u32 bit = __bit(nr);
+
+	writel(bit, &regs->dirs);
+	/* Data register after direction, otherwise pullup/down is selected */
+	if (val)
+		writel(bit, &regs->dats);
+	else
+		writel(bit, &regs->datc);
+	return 0;
+}
+
+static int gsta_gpio_direction_input(struct gpio_chip *gpio, unsigned nr)
+{
+	struct gsta_gpio *chip = container_of(gpio, struct gsta_gpio, gpio);
+	struct gsta_regs __iomem *regs = __regs(chip, nr);
+	u32 bit = __bit(nr);
+
+	writel(bit, &regs->dirc);
+	return 0;
+}
+
+static int gsta_gpio_to_irq(struct gpio_chip *gpio, unsigned offset)
+{
+	struct gsta_gpio *chip = container_of(gpio, struct gsta_gpio, gpio);
+	return chip->irq_base + offset;
+}
+
+static void gsta_gpio_setup(struct gsta_gpio *chip) /* called from probe */
+{
+	struct gpio_chip *gpio = &chip->gpio;
+
+	/*
+	 * ARCH_NR_GPIOS is currently 256 and dynamic allocation starts
+	 * from the end. However, for compatibility, we need the first
+	 * ConneXt device to start from gpio 0: it's the main chipset
+	 * on most boards so documents and drivers assume gpio0..gpio127
+	 */
+	static int gpio_base;
+
+	gpio->label = dev_name(chip->dev);
+	gpio->owner = THIS_MODULE;
+	gpio->direction_input = gsta_gpio_direction_input;
+	gpio->get = gsta_gpio_get;
+	gpio->direction_output = gsta_gpio_direction_output;
+	gpio->set = gsta_gpio_set;
+	gpio->dbg_show = NULL;
+	gpio->base = gpio_base;
+	gpio->ngpio = GSTA_NR_GPIO;
+	gpio->can_sleep = 0;
+	gpio->to_irq = gsta_gpio_to_irq;
+
+	/*
+	 * After the first device, turn to dynamic gpio numbers.
+	 * For example, with ARCH_NR_GPIOS = 256 we can fit two cards
+	 */
+	if (!gpio_base)
+		gpio_base = -1;
+}
+
+/*
+ * Special method: alternate functions and pullup/pulldown. This is only
+ * invoked on startup to configure gpio's according to platform data.
+ * FIXME : this functionality shall be managed (and exported to other drivers)
+ * via the pin control subsystem.
+ */
+static void gsta_set_config(struct gsta_gpio *chip, int nr, unsigned cfg)
+{
+	struct gsta_regs __iomem *regs = __regs(chip, nr);
+	unsigned long flags;
+	u32 bit = __bit(nr);
+	u32 val;
+	int err = 0;
+
+	pr_info("%s: %p %i %i\n", __func__, chip, nr, cfg);
+
+	if (cfg == PINMUX_TYPE_NONE)
+		return;
+
+	/* Alternate function or not? */
+	spin_lock_irqsave(&chip->lock, flags);
+	val = readl(&regs->afsela);
+	if (cfg == PINMUX_TYPE_FUNCTION)
+		val |= bit;
+	else
+		val &= ~bit;
+	writel(val | bit, &regs->afsela);
+	if (cfg == PINMUX_TYPE_FUNCTION) {
+		spin_unlock_irqrestore(&chip->lock, flags);
+		return;
+	}
+
+	/* not alternate function: set details */
+	switch (cfg) {
+	case PINMUX_TYPE_OUTPUT_LOW:
+		writel(bit, &regs->dirs);
+		writel(bit, &regs->datc);
+		break;
+	case PINMUX_TYPE_OUTPUT_HIGH:
+		writel(bit, &regs->dirs);
+		writel(bit, &regs->dats);
+		break;
+	case PINMUX_TYPE_INPUT:
+		writel(bit, &regs->dirc);
+		val = readl(&regs->pdis) | bit;
+		writel(val, &regs->pdis);
+		break;
+	case PINMUX_TYPE_INPUT_PULLUP:
+		writel(bit, &regs->dirc);
+		val = readl(&regs->pdis) & ~bit;
+		writel(val, &regs->pdis);
+		writel(bit, &regs->dats);
+		break;
+	case PINMUX_TYPE_INPUT_PULLDOWN:
+		writel(bit, &regs->dirc);
+		val = readl(&regs->pdis) & ~bit;
+		writel(val, &regs->pdis);
+		writel(bit, &regs->datc);
+		break;
+	default:
+		err = 1;
+	}
+	spin_unlock_irqrestore(&chip->lock, flags);
+	if (err)
+		pr_err("%s: chip %p, pin %i, cfg %i is invalid\n",
+		       __func__, chip, nr, cfg);
+}
+
+/*
+ * Irq methods
+ */
+
+static void gsta_irq_disable(struct irq_data *data)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
+	struct gsta_gpio *chip = gc->private;
+	int nr = data->irq - chip->irq_base;
+	struct gsta_regs __iomem *regs = __regs(chip, nr);
+	u32 bit = __bit(nr);
+	u32 val;
+	unsigned long flags;
+
+	spin_lock_irqsave(&chip->lock, flags);
+	if (chip->irq_type[nr] & IRQ_TYPE_EDGE_RISING) {
+		val = readl(&regs->rimsc) & ~bit;
+		writel(val, &regs->rimsc);
+	}
+	if (chip->irq_type[nr] & IRQ_TYPE_EDGE_FALLING) {
+		val = readl(&regs->fimsc) & ~bit;
+		writel(val, &regs->fimsc);
+	}
+	spin_unlock_irqrestore(&chip->lock, flags);
+	return;
+}
+
+static void gsta_irq_enable(struct irq_data *data)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
+	struct gsta_gpio *chip = gc->private;
+	int nr = data->irq - chip->irq_base;
+	struct gsta_regs __iomem *regs = __regs(chip, nr);
+	u32 bit = __bit(nr);
+	u32 val;
+	int type;
+	unsigned long flags;
+
+	type = chip->irq_type[nr];
+
+	spin_lock_irqsave(&chip->lock, flags);
+	val = readl(&regs->rimsc);
+	if (type & IRQ_TYPE_EDGE_RISING)
+		writel(val | bit, &regs->rimsc);
+	else
+		writel(val & ~bit, &regs->rimsc);
+	val = readl(&regs->rimsc);
+	if (type & IRQ_TYPE_EDGE_FALLING)
+		writel(val | bit, &regs->fimsc);
+	else
+		writel(val & ~bit, &regs->fimsc);
+	spin_unlock_irqrestore(&chip->lock, flags);
+	return;
+}
+
+static int gsta_irq_type(struct irq_data *d, unsigned int type)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct gsta_gpio *chip = gc->private;
+	int nr = d->irq - chip->irq_base;
+
+	/* We only support edge interrupts */
+	if (!(type & (IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING))) {
+		pr_debug("%s: unsupported type 0x%x\n", __func__, type);
+		return -EINVAL;
+	}
+
+	chip->irq_type[nr] = type; /* used for enable/disable */
+
+	gsta_irq_enable(d);
+	return 0;
+}
+
+static irqreturn_t gsta_gpio_handler(int irq, void *dev_id)
+{
+	struct gsta_gpio *chip = dev_id;
+	struct gsta_regs __iomem *regs;
+	u32 is;
+	int i, nr, base;
+	irqreturn_t ret = IRQ_NONE;
+
+	for (i = 0; i < GSTA_NR_BLOCKS; i++) {
+		regs = chip->regs[i];
+		base = chip->irq_base + i * GSTA_GPIO_PER_BLOCK;
+		while ((is = readl(&regs->is))) {
+			nr = __ffs(is);
+			irq = base + nr;
+			generic_handle_irq(irq);
+			writel(1 << nr, &regs->ic);
+			ret = IRQ_HANDLED;
+		}
+	}
+	return ret;
+}
+
+static __devinit void gsta_alloc_irq_chip(struct gsta_gpio *chip)
+{
+	struct irq_chip_generic *gc;
+	struct irq_chip_type *ct;
+
+	gc = irq_alloc_generic_chip(KBUILD_MODNAME, 1, chip->irq_base,
+				     chip->reg_base, handle_simple_irq);
+	gc->private = chip;
+	ct = gc->chip_types;
+
+	ct->chip.irq_set_type = gsta_irq_type;
+	ct->chip.irq_disable = gsta_irq_disable;
+	ct->chip.irq_enable = gsta_irq_enable;
+
+	/* FIXME: this makes at most 32 interrupts. Request 0 by now */
+	irq_setup_generic_chip(gc, 0 /* IRQ_MSK(GSTA_GPIO_PER_BLOCK) */, 0,
+			       IRQ_NOREQUEST | IRQ_NOPROBE, 0);
+
+	/* Set up all all 128 interrupts: code from setup_generic_chip */
+	{
+		struct irq_chip_type *ct = gc->chip_types;
+		int i, j;
+		for (j = 0; j < GSTA_NR_GPIO; j++) {
+			i = chip->irq_base + j;
+			irq_set_chip_and_handler(i, &ct->chip, ct->handler);
+			irq_set_chip_data(i, gc);
+			irq_modify_status(i, IRQ_NOREQUEST | IRQ_NOPROBE, 0);
+		}
+		gc->irq_cnt = i - gc->irq_base;
+	}
+}
+
+/* The platform device used here is instantiated by the MFD device */
+static int __devinit gsta_probe(struct platform_device *dev)
+{
+	int i, err;
+	struct pci_dev *pdev;
+	struct sta2x11_gpio_pdata *gpio_pdata;
+	struct gsta_gpio *chip;
+	struct resource *res;
+
+	pdev = *(struct pci_dev **)(dev->dev.platform_data);
+	gpio_pdata = dev_get_platdata(&pdev->dev);
+
+	if (gpio_pdata == NULL)
+		dev_err(&dev->dev, "no gpio config\n");
+	pr_debug("gpio config: %p\n", gpio_pdata);
+
+	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+
+	chip = devm_kzalloc(&dev->dev, sizeof(*chip), GFP_KERNEL);
+	chip->dev = &dev->dev;
+	chip->reg_base = devm_request_and_ioremap(&dev->dev, res);
+
+	for (i = 0; i < GSTA_NR_BLOCKS; i++) {
+		chip->regs[i] = chip->reg_base + i * 4096;
+		/* disable all irqs */
+		writel(0, &chip->regs[i]->rimsc);
+		writel(0, &chip->regs[i]->fimsc);
+		writel(~0, &chip->regs[i]->ic);
+	}
+	spin_lock_init(&chip->lock);
+	gsta_gpio_setup(chip);
+	for (i = 0; i < GSTA_NR_GPIO; i++)
+		gsta_set_config(chip, i, gpio_pdata->pinconfig[i]);
+
+	/* 384 was used in previous code: be compatible for other drivers */
+	err = irq_alloc_descs(-1, 384, GSTA_NR_GPIO, NUMA_NO_NODE);
+	if (err < 0) {
+		dev_warn(&dev->dev, "sta2x11 gpio: Can't get irq base (%i)\n",
+			 -err);
+		return err;
+	}
+	chip->irq_base = err;
+	gsta_alloc_irq_chip(chip);
+
+	err = request_irq(pdev->irq, gsta_gpio_handler,
+			     IRQF_SHARED, KBUILD_MODNAME, chip);
+	if (err < 0) {
+		dev_err(&dev->dev, "sta2x11 gpio: Can't request irq (%i)\n",
+			-err);
+		goto err_free_descs;
+	}
+
+	err = gpiochip_add(&chip->gpio);
+	if (err < 0) {
+		dev_err(&dev->dev, "sta2x11 gpio: Can't register (%i)\n",
+			-err);
+		goto err_free_irq;
+	}
+
+	platform_set_drvdata(dev, chip);
+	return 0;
+
+err_free_irq:
+	free_irq(pdev->irq, chip);
+err_free_descs:
+	irq_free_descs(chip->irq_base, GSTA_NR_GPIO);
+	return err;
+}
+
+static struct platform_driver sta2x11_gpio_platform_driver = {
+	.driver = {
+		.name	= "sta2x11-gpio",
+		.owner	= THIS_MODULE,
+	},
+	.probe = gsta_probe,
+};
+
+module_platform_driver(sta2x11_gpio_platform_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("sta2x11_gpio GPIO driver");