Date:	Thu, 26 Jan 2012 16:52:55 +0100
From:	Alessandro Rubini <rubini@...dd.com>
To:	linux-kernel@...r.kernel.org
Cc:	giancarlo.asnaghi@...com, alan@...ux.intel.com,
	grant.likely@...retlab.ca, linus.walleij@...ricsson.com
Subject: [RFC PATCH 2/2] gpio: add STA2X11 GPIO block

This introduces 128 gpio bits (for each device) and with interrupt support.
It is tested and working, but it's still an RFC.

It still misses the alternate-function and pull-up/pull-down support.
I don't know if it should be a different patch or merged in this the
next time I submit.

Moreover, this is an RFC as described in the cover letter 0/2

Signed-off-by: Alessandro Rubini <rubini@...dd.com>
Acked-by: Giancarlo Asnaghi <giancarlo.asnaghi@...com>
---
 drivers/gpio/Kconfig        |    9 +
 drivers/gpio/Makefile       |    1 +
 drivers/gpio/gpio-sta2x11.c |  380 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 390 insertions(+), 0 deletions(-)
 create mode 100644 drivers/gpio/gpio-sta2x11.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index d0c4118..fab6ca7 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -149,6 +149,14 @@ config GPIO_PXA
 	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
@@ -489,4 +497,5 @@ config GPIO_TPS65910
 	help
 	  Select this option to enable GPIO driver for the TPS65910
 	  chip family.
+
 endif
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index fa10df6..81a28cf 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -45,6 +45,7 @@ obj-$(CONFIG_GPIO_RDC321X)	+= gpio-rdc321x.o
 obj-$(CONFIG_PLAT_SAMSUNG)	+= gpio-samsung.o
 obj-$(CONFIG_ARCH_SA1100)	+= gpio-sa1100.o
 obj-$(CONFIG_GPIO_SCH)		+= gpio-sch.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
diff --git a/drivers/gpio/gpio-sta2x11.c b/drivers/gpio/gpio-sta2x11.c
new file mode 100644
index 0000000..377dcb1
--- /dev/null
+++ b/drivers/gpio/gpio-sta2x11.c
@@ -0,0 +1,380 @@
+/*
+ * 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	*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 compatiility, we need the first
+	 * ConneXt device to start from gpio 0, because it's the main
+	 * chipset on most boards both documents and drivers assume that.
+	 */
+	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->base = 0;
+	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.
+	 * With ARCH_NR_GPIOS = 256 we can fit for example two steval cards
+	 */
+	if (!gpio_base)
+		gpio_base = 1;
+}
+
+/*
+ * Special methods: alternate functins and pullup/pulldown
+ */
+
+/* FIXME */
+
+/*
+ * 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);
+	}
+	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_data;
+	struct gsta_gpio *chip;
+	struct resource *res;
+
+	pdev = *(struct pci_dev **)(dev->dev.platform_data);
+	gpio_data = dev_get_platdata(&pdev->dev);
+
+	if (gpio_data == NULL)
+		dev_err(&dev->dev, "%s, NULL gpio config\n", __func__);
+	/* FIXME: use gpio_data */
+
+	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+	request_mem_region(res->start, resource_size(res), KBUILD_MODNAME);
+
+
+	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+	chip->dev = &dev->dev;
+	chip->reg_base = ioremap(res->start, resource_size(res));
+	chip->irq_base = -1;
+	spin_lock_init(&chip->lock);
+	gsta_gpio_setup(chip);
+	err = gpiochip_add(&chip->gpio);
+	if (err < 0) {
+		dev_err(&dev->dev, "sta2x11 gpio: Can't register (%i)\n",
+			-err);
+		kfree(chip);
+		return err;
+	}
+	/* 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);
+		goto err_out;
+	}
+	chip->irq_base = err;
+	gsta_alloc_irq_chip(chip);
+
+	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);
+	}
+
+	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_out;
+	}
+
+	platform_set_drvdata(dev, chip);
+	return 0;
+
+err_out:
+	if (chip->irq_base > 0)
+		irq_free_descs(chip->irq_base, GSTA_NR_GPIO);
+	kfree(chip);
+	return err;
+}
+
+static struct platform_driver sta2x11_gpio_platform_driver = {
+	.driver = {
+		.name	= "sta2x11-gpio",
+		.owner	= THIS_MODULE,
+	},
+	.probe = gsta_probe,
+};
+
+static int __init sta2x11_gpio_init(void)
+{
+	return platform_driver_register(&sta2x11_gpio_platform_driver);
+}
+
+module_init(sta2x11_gpio_init);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("sta2x11_gpio GPIO driver");
-- 
1.7.7.2
--
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