[PATCH] gpio: Add device driver for GRGPIO cores and support custom accessors with gpio-generic

From: Andreas Larsson
Date: Thu Feb 14 2013 - 02:56:20 EST

This driver supports GRGPIO gpio cores available in the GRLIB VHDL IP
core library from Aeroflex Gaisler.

This also adds support to gpio-generic for using custom accessor
functions. The grgpio driver uses this to use ioread32be and iowrite32be
for big endian register accesses.

Reviewed-by: Anton Vorontsov <anton@xxxxxxxxxx>
Signed-off-by: Andreas Larsson <andreas@xxxxxxxxxxx>
---

Changes since v3:
- Add Reveiwed-by
- Fix pointed out style issues
- Use np->full_name directly instead of kstrdup'ing it as it is a const char*
- Call gpiochip_remove in grgpio_remove

.../devicetree/bindings/gpio/gpio-grgpio.txt | 29 +++
drivers/gpio/Kconfig | 8 +
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-generic.c | 26 ++-
drivers/gpio/gpio-grgpio.c | 253 ++++++++++++++++++++
5 files changed, 308 insertions(+), 9 deletions(-)
create mode 100644 Documentation/devicetree/bindings/gpio/gpio-grgpio.txt
create mode 100644 drivers/gpio/gpio-grgpio.c

diff --git a/Documentation/devicetree/bindings/gpio/gpio-grgpio.txt b/Documentation/devicetree/bindings/gpio/gpio-grgpio.txt
new file mode 100644
index 0000000..36f456f
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-grgpio.txt
@@ -0,0 +1,29 @@
+Aeroflex Gaisler GRGPIO General Purpose I/O cores.
+
+The GRGPIO GPIO core is available in the GRLIB VHDL IP core library.
+
+Note: In the ordinary ordinary environment for the GRGPIO core, a Leon SPARC
+system, these properties are built from information in the AMBA plug&play.
+
+Required properties:
+
+- name : Should be "GAISLER_GPIO" or "01_01a"
+
+- reg : Address and length of the register set for the device
+
+- interrupts : Interrupt numbers for this device
+
+Optional properties:
+
+- base : The base gpio number for the core. A dynamic base is used if not
+ present
+
+- nbits : The number of gpio lines. If not present driver assumes 32 lines.
+
+- irqmap : An array with an index for each gpio line. An index is either a valid
+ index into the interrupts property array, or 0xffffffff that indicates
+ no irq for that line. Driver provides no interrupt support if not
+ present.
+
+For further information look in the documentation for the GLIB IP core library:
+http://www.gaisler.com/products/grlib/grip.pdf
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index ab97eb8..5472778 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -309,6 +309,14 @@ config GPIO_LYNXPOINT
driver for GPIO functionality on Intel Lynxpoint PCH chipset
Requires ACPI device enumeration code to set up a platform device.

+config GPIO_GRGPIO
+ tristate "Aeroflex Gaisler GRGPIO support"
+ depends on OF
+ select GPIO_GENERIC
+ help
+ Select this to support Aeroflex Gaisler GRGPIO cores from the GRLIB
+ VHDL IP core library.
+
comment "I2C GPIO expanders:"

config GPIO_ARIZONA
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 4398034..f3b49a2 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_ARCH_DAVINCI) += gpio-davinci.o
obj-$(CONFIG_GPIO_EM) += gpio-em.o
obj-$(CONFIG_GPIO_EP93XX) += gpio-ep93xx.o
obj-$(CONFIG_GPIO_GE_FPGA) += gpio-ge.o
+obj-$(CONFIG_GPIO_GRGPIO) += gpio-grgpio.o
obj-$(CONFIG_GPIO_ICH) += gpio-ich.o
obj-$(CONFIG_GPIO_IT8761E) += gpio-it8761e.o
obj-$(CONFIG_GPIO_JANZ_TTL) += gpio-janz-ttl.o
diff --git a/drivers/gpio/gpio-generic.c b/drivers/gpio/gpio-generic.c
index 05fcc0f..f854799 100644
--- a/drivers/gpio/gpio-generic.c
+++ b/drivers/gpio/gpio-generic.c
@@ -251,24 +251,25 @@ static int bgpio_setup_accessors(struct device *dev,
struct bgpio_chip *bgc,
bool be)
{
+ struct bgpio_chip def;

switch (bgc->bits) {
case 8:
- bgc->read_reg = bgpio_read8;
- bgc->write_reg = bgpio_write8;
+ def.read_reg = bgpio_read8;
+ def.write_reg = bgpio_write8;
break;
case 16:
- bgc->read_reg = bgpio_read16;
- bgc->write_reg = bgpio_write16;
+ def.read_reg = bgpio_read16;
+ def.write_reg = bgpio_write16;
break;
case 32:
- bgc->read_reg = bgpio_read32;
- bgc->write_reg = bgpio_write32;
+ def.read_reg = bgpio_read32;
+ def.write_reg = bgpio_write32;
break;
#if BITS_PER_LONG >= 64
case 64:
- bgc->read_reg = bgpio_read64;
- bgc->write_reg = bgpio_write64;
+ def.read_reg = bgpio_read64;
+ def.write_reg = bgpio_write64;
break;
#endif /* BITS_PER_LONG >= 64 */
default:
@@ -276,7 +277,14 @@ static int bgpio_setup_accessors(struct device *dev,
return -EINVAL;
}

- bgc->pin2mask = be ? bgpio_pin2mask_be : bgpio_pin2mask;
+ def.pin2mask = be ? bgpio_pin2mask_be : bgpio_pin2mask;
+
+ if (!bgc->read_reg)
+ bgc->read_reg = def.read_reg;
+ if (!bgc->write_reg)
+ bgc->write_reg = def.write_reg;
+ if (!bgc->pin2mask)
+ bgc->pin2mask = def.pin2mask;

return 0;
}
diff --git a/drivers/gpio/gpio-grgpio.c b/drivers/gpio/gpio-grgpio.c
new file mode 100644
index 0000000..b1ec475
--- /dev/null
+++ b/drivers/gpio/gpio-grgpio.c
@@ -0,0 +1,253 @@
+/*
+ * Driver for Aeroflex Gaisler GRGPIO General Purpose I/O cores.
+ *
+ * 2013 (c) Aeroflex Gaisler AB
+ *
+ * This driver supports the GRGPIO GPIO core available in the GRLIB VHDL IP core
+ * library.
+ *
+ * Full documentation of the GRGPIO core can be found here:
+ * http://www.gaisler.com/products/grlib/grip.pdf
+ *
+ * See "Documentation/devicetree/bindings/gpio/gpio-grgpio.txt" for information
+ * on open firmware properties.
+ *
+ * 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.
+ *
+ * Contributors: Andreas Larsson <andreas@xxxxxxxxxxx>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/of_platform.h>
+#include <linux/of_irq.h>
+#include <linux/gpio.h>
+#include <linux/slab.h>
+#include <linux/irq.h>
+#include <linux/basic_mmio_gpio.h>
+
+#define GRGPIO_MAX_NGPIO 32
+
+struct grgpio_regs {
+ u32 data; /* 0x00 */
+ u32 output; /* 0x04 */
+ u32 dir; /* 0x08 */
+ u32 imask; /* 0x0c */
+ u32 ipol; /* 0x10 */
+ u32 iedge; /* 0x14 */
+ u32 bypass; /* 0x18 */
+ u32 __reserved; /* 0x1c */
+ u32 imap[8]; /* 0x20-0x3c */
+};
+
+struct grgpio_priv {
+ struct bgpio_chip bgc;
+ struct grgpio_regs __iomem *regs;
+
+ u32 imask; /* irq mask shadow register */
+ s32 *irqmap; /* maps offset to irq or -1 if no irq */
+};
+
+static unsigned long grgpio_read_reg(void __iomem *reg)
+{
+ return ioread32be(reg);
+}
+
+static void grgpio_write_reg(void __iomem *reg, unsigned long data)
+{
+ iowrite32be(data, reg);
+}
+
+static inline struct grgpio_priv *grgpio_gc_to_priv(struct gpio_chip *gc)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+
+ return container_of(bgc, struct grgpio_priv, bgc);
+}
+
+static void grgpio_set_imask(struct grgpio_priv *priv, unsigned int offset,
+ int val)
+{
+ struct bgpio_chip *bgc = &priv->bgc;
+ unsigned long mask = bgc->pin2mask(bgc, offset);
+ unsigned long flags;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+
+ if (val)
+ priv->imask |= mask;
+ else
+ priv->imask &= ~mask;
+ bgc->write_reg(&priv->regs->imask, priv->imask);
+
+ spin_unlock_irqrestore(&bgc->lock, flags);
+}
+
+static int grgpio_to_irq(struct gpio_chip *gc, unsigned offset)
+{
+ struct grgpio_priv *priv = grgpio_gc_to_priv(gc);
+ int index;
+ int irq;
+
+ if (!priv->irqmap || offset > gc->ngpio)
+ return -ENXIO;
+
+ index = priv->irqmap[offset];
+ if (index < 0)
+ return -ENXIO;
+
+ irq = irq_of_parse_and_map(priv->bgc.gc.dev->of_node, index);
+ if (irq) {
+ /* Enable interrupt and return irq */
+ grgpio_set_imask(priv, offset, 1);
+ return irq;
+ }
+
+ return -ENXIO;
+}
+
+static void grgpio_free(struct gpio_chip *gc, unsigned offset)
+{
+ struct grgpio_priv *priv = grgpio_gc_to_priv(gc);
+ struct bgpio_chip *bgc = &priv->bgc;
+ unsigned long mask = bgc->pin2mask(bgc, offset);
+
+ if (unlikely(priv->imask & mask))
+ grgpio_set_imask(priv, offset, 0);
+}
+
+static int grgpio_probe(struct platform_device *ofdev)
+{
+ struct device_node *np = ofdev->dev.of_node;
+ struct grgpio_regs __iomem *regs;
+ struct gpio_chip *gc;
+ struct bgpio_chip *bgc;
+ struct grgpio_priv *priv;
+ struct resource *res;
+ int err;
+ int size;
+ u32 prop;
+ s32 *irqmap;
+
+ priv = devm_kzalloc(&ofdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
+ regs = devm_request_and_ioremap(&ofdev->dev, res);
+ if (!regs) {
+ dev_err(&ofdev->dev, "Couldn't map registers\n");
+ return -EADDRNOTAVAIL;
+ }
+
+ bgc = &priv->bgc;
+ bgc->read_reg = grgpio_read_reg;
+ bgc->write_reg = grgpio_write_reg;
+ err = bgpio_init(bgc, &ofdev->dev, 4, &regs->data, &regs->output, NULL,
+ &regs->dir, NULL, 0);
+ if (err) {
+ dev_err(&ofdev->dev, "bgpio_init() failed\n");
+ return err;
+ }
+
+ priv->regs = regs;
+ priv->imask = bgc->read_reg(&regs->imask);
+
+ gc = &bgc->gc;
+ gc->of_node = np;
+ gc->owner = THIS_MODULE;
+ gc->to_irq = grgpio_to_irq;
+ gc->free = grgpio_free;
+ gc->label = np->full_name;
+
+ err = of_property_read_u32(np, "base", &prop);
+ if (err) {
+ dev_dbg(&ofdev->dev, "No base property: use dynamic base\n");
+ gc->base = -1;
+ } else {
+ gc->base = prop;
+ }
+
+ err = of_property_read_u32(np, "nbits", &prop);
+ if (err || prop <= 0 || prop > GRGPIO_MAX_NGPIO) {
+ gc->ngpio = GRGPIO_MAX_NGPIO;
+ dev_dbg(&ofdev->dev,
+ "No or invalid nbits property: assume %d\n", gc->ngpio);
+ } else {
+ gc->ngpio = prop;
+ }
+
+ irqmap = (s32 *)of_get_property(np, "irqmap", &size);
+ if (irqmap) {
+ int i;
+
+ if (size < gc->ngpio) {
+ dev_err(&ofdev->dev,
+ "irqmap shorter than ngpio (%d < %d)\n",
+ size, gc->ngpio);
+ return -EINVAL;
+ }
+
+ priv->irqmap = devm_kzalloc(&ofdev->dev,
+ gc->ngpio * sizeof(s32),
+ GFP_KERNEL);
+ if (!priv->irqmap)
+ return -ENOMEM;
+
+ for (i = 0; i < gc->ngpio; i++)
+ priv->irqmap[i] = irqmap[i];
+ } else {
+ dev_dbg(&ofdev->dev, "No irqmap\n");
+ }
+
+ platform_set_drvdata(ofdev, priv);
+
+ err = gpiochip_add(gc);
+ if (err) {
+ dev_err(&ofdev->dev, "Couldn't add gpiochip\n");
+ return err;
+ }
+
+ dev_info(&ofdev->dev, "regs=0x%p, base=%d, npgio=%d\n",
+ priv->regs, gc->base, gc->ngpio);
+
+ return 0;
+}
+
+static int grgpio_remove(struct platform_device *ofdev)
+{
+ struct grgpio_priv *priv = platform_get_drvdata(ofdev);
+
+ return gpiochip_remove(&priv->bgc.gc);
+}
+
+static struct of_device_id grgpio_match[] = {
+ {.name = "GAISLER_GPIO"},
+ {.name = "01_01a"},
+ {},
+};
+
+MODULE_DEVICE_TABLE(of, grgpio_match);
+
+static struct platform_driver grgpio_driver = {
+ .driver = {
+ .name = "grgpio",
+ .owner = THIS_MODULE,
+ .of_match_table = grgpio_match,
+ },
+ .probe = grgpio_probe,
+ .remove = grgpio_remove,
+};
+module_platform_driver(grgpio_driver);
+
+MODULE_AUTHOR("Aeroflex Gaisler AB.");
+MODULE_DESCRIPTION("Driver for Aeroflex Gaisler GRGPIO");
+MODULE_LICENSE("GPL");
--
1.7.0.4

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