* [PATCH 2/2] [POWERPC] Implement support for the GPIO LIB API
2008-04-11 13:05 [PATCH 0/2] Notorious OF GPIO API support Anton Vorontsov
@ 2008-04-11 13:06 ` Anton Vorontsov
2008-04-11 14:16 ` Grant Likely
2008-04-11 13:06 ` [PATCH 1/2] OF helpers for the GPIO API Anton Vorontsov
1 sibling, 1 reply; 5+ messages in thread
From: Anton Vorontsov @ 2008-04-11 13:06 UTC (permalink / raw)
To: Paul Mackerras; +Cc: linuxppc-dev, David Miller
This patch implements support for the GPIO LIB API. Two calls
unimplemented though: irq_to_gpio and gpio_to_irq.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
---
Documentation/powerpc/booting-without-of.txt | 52 ++++++++++++++++++++++++
arch/powerpc/Kconfig | 5 ++
include/asm-powerpc/gpio.h | 56 ++++++++++++++++++++++++++
3 files changed, 113 insertions(+), 0 deletions(-)
create mode 100644 include/asm-powerpc/gpio.h
diff --git a/Documentation/powerpc/booting-without-of.txt b/Documentation/powerpc/booting-without-of.txt
index b506245..e9e0c2f 100644
--- a/Documentation/powerpc/booting-without-of.txt
+++ b/Documentation/powerpc/booting-without-of.txt
@@ -66,6 +66,10 @@ Table of Contents
3) OpenPIC Interrupt Controllers
4) ISA Interrupt Controllers
+ VIII - Specifying GPIO information for devices
+ 1) gpios property
+ 2) gpio-controller nodes
+
Appendix A - Sample SOC node for MPC8540
@@ -2925,6 +2929,54 @@ encodings listed below:
2 = high to low edge sensitive type enabled
3 = low to high edge sensitive type enabled
+VIII - Specifying GPIO information for devices
+==============================================
+
+1) gpios property
+-----------------
+
+Nodes that makes use of GPIOs should define them using `gpios' property,
+format of which is: <&gpio-controller1-phandle gpio1-specifier
+ &gpio-controller2-phandle gpio2-specifier
+ 0 /* holes are permitted, means no GPIO 3 */
+ &gpio-controller4-phandle gpio4-specifier
+ ...>;
+
+Note that gpio-specifier length is controller dependent.
+
+gpio-specifier may encode: bank, pin position inside the bank,
+whether pin is open-drain and whether pin is logically inverted.
+
+Example of the node using GPIOs:
+
+ node {
+ gpios = <&qe_pio_e 18 0>;
+ };
+
+In this example gpio-specifier is "18 0" and encodes GPIO pin number,
+and empty GPIO flags as accepted by the "qe_pio_e" gpio-controller.
+
+2) gpio-controller nodes
+------------------------
+
+Every GPIO controller node must have #gpio-cells property defined,
+this information will be used to translate gpio-specifiers.
+
+Example of two SOC GPIO banks defined as gpio-controller nodes:
+
+ qe_pio_a: gpio-controller@1400 {
+ #gpio-cells = <2>;
+ compatible = "fsl,qe-pario-bank-a", "fsl,qe-pario-bank";
+ reg = <0x1400 0x18>;
+ gpio-controller;
+ };
+
+ qe_pio_e: gpio-controller@1460 {
+ #gpio-cells = <2>;
+ compatible = "fsl,qe-pario-bank-e", "fsl,qe-pario-bank";
+ reg = <0x1460 0x18>;
+ gpio-controller;
+ };
Appendix A - Sample SOC node for MPC8540
========================================
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 0b27cbd..f328509 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -81,6 +81,11 @@ config GENERIC_FIND_NEXT_BIT
bool
default y
+config GENERIC_GPIO
+ bool
+ help
+ Generic GPIO API support
+
config ARCH_NO_VIRT_TO_BUS
def_bool PPC64
diff --git a/include/asm-powerpc/gpio.h b/include/asm-powerpc/gpio.h
new file mode 100644
index 0000000..77ad3a8
--- /dev/null
+++ b/include/asm-powerpc/gpio.h
@@ -0,0 +1,56 @@
+/*
+ * Generic GPIO API implementation for PowerPC.
+ *
+ * Copyright (c) 2007-2008 MontaVista Software, Inc.
+ *
+ * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
+ *
+ * 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.
+ */
+
+#ifndef __ASM_POWERPC_GPIO_H
+#define __ASM_POWERPC_GPIO_H
+
+#include <linux/errno.h>
+#include <asm-generic/gpio.h>
+
+#ifdef CONFIG_HAVE_GPIO_LIB
+
+/*
+ * We don't (yet) implement inlined/rapid versions for on-chip gpios.
+ * Just call gpiolib.
+ */
+static inline int gpio_get_value(unsigned int gpio)
+{
+ return __gpio_get_value(gpio);
+}
+
+static inline void gpio_set_value(unsigned int gpio, int value)
+{
+ __gpio_set_value(gpio, value);
+}
+
+static inline int gpio_cansleep(unsigned int gpio)
+{
+ return __gpio_cansleep(gpio);
+}
+
+/*
+ * Not implemented, yet.
+ */
+static inline int gpio_to_irq(unsigned int gpio)
+{
+ return -ENOSYS;
+}
+
+static inline int irq_to_gpio(unsigned int irq)
+{
+ return -EINVAL;
+}
+
+#endif /* CONFIG_HAVE_GPIO_LIB */
+
+#endif /* __ASM_POWERPC_GPIO_H */
--
1.5.4.5
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH 1/2] OF helpers for the GPIO API
2008-04-11 13:05 [PATCH 0/2] Notorious OF GPIO API support Anton Vorontsov
2008-04-11 13:06 ` [PATCH 2/2] [POWERPC] Implement support for the GPIO LIB API Anton Vorontsov
@ 2008-04-11 13:06 ` Anton Vorontsov
2008-04-11 14:28 ` Grant Likely
1 sibling, 1 reply; 5+ messages in thread
From: Anton Vorontsov @ 2008-04-11 13:06 UTC (permalink / raw)
To: Paul Mackerras; +Cc: linuxppc-dev, David Miller
This patch implements various helpers to support OF bindings for
the GPIO LIB API.
Previously this was PowerPC specific, but it seems this code
isn't arch-dependent anyhow, so let's place it into of/.
SPARC will not see this addition yet, real hardware seem to not use
GPIOs at all. But this might change:
http://www.leox.org/docs/faq_MLleon.html
"16-bit I/O port" sounds promising. :-)
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
---
drivers/of/Kconfig | 6 +
drivers/of/Makefile | 1 +
drivers/of/gpio.c | 242 +++++++++++++++++++++++++++++++++++++++++++++++
include/linux/of_gpio.h | 69 +++++++++++++
4 files changed, 318 insertions(+), 0 deletions(-)
create mode 100644 drivers/of/gpio.c
create mode 100644 include/linux/of_gpio.h
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index c03072b..3354ad7 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -1,3 +1,9 @@
config OF_DEVICE
def_bool y
depends on OF && (SPARC || PPC_OF)
+
+config OF_GPIO
+ def_bool y
+ depends on OF && PPC_OF && HAVE_GPIO_LIB
+ help
+ OpenFirmware GPIO accessors
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index ab9be5d..5a61f70 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -1,2 +1,3 @@
obj-y = base.o
obj-$(CONFIG_OF_DEVICE) += device.o platform.o
+obj-$(CONFIG_OF_GPIO) += gpio.o
diff --git a/drivers/of/gpio.c b/drivers/of/gpio.c
new file mode 100644
index 0000000..000681e
--- /dev/null
+++ b/drivers/of/gpio.c
@@ -0,0 +1,242 @@
+/*
+ * OF helpers for the GPIO API
+ *
+ * Copyright (c) 2007-2008 MontaVista Software, Inc.
+ *
+ * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <asm/prom.h>
+
+/**
+ * of_get_gpio - Get a GPIO number from the device tree to use with GPIO API
+ * @np: device node to get GPIO from
+ * @index: index of the GPIO
+ *
+ * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
+ * value on the error condition.
+ */
+int of_get_gpio(struct device_node *np, int index)
+{
+ int ret = -EINVAL;
+ struct device_node *gc;
+ struct of_gpio_chip *of_gc = NULL;
+ int size;
+ const u32 *gpios;
+ u32 nr_cells;
+ int i;
+ const void *gpio_spec;
+ const u32 *gpio_cells;
+ int gpio_index = 0;
+
+ gpios = of_get_property(np, "gpios", &size);
+ if (!gpios) {
+ ret = -ENOENT;
+ goto err0;
+ }
+ nr_cells = size / sizeof(u32);
+
+ for (i = 0; i < nr_cells; gpio_index++) {
+ const phandle *gpio_phandle;
+
+ gpio_phandle = gpios + i;
+ gpio_spec = gpio_phandle + 1;
+
+ /* one cell hole in the gpios = <>; */
+ if (!*gpio_phandle) {
+ if (gpio_index == index)
+ return -ENOENT;
+ i++;
+ continue;
+ }
+
+ gc = of_find_node_by_phandle(*gpio_phandle);
+ if (!gc) {
+ pr_debug("%s: could not find phandle for gpios\n",
+ np->full_name);
+ goto err0;
+ }
+
+ of_gc = gc->data;
+ if (!of_gc) {
+ pr_debug("%s: gpio controller %s isn't registered\n",
+ np->full_name, gc->full_name);
+ goto err1;
+ }
+
+ gpio_cells = of_get_property(gc, "#gpio-cells", &size);
+ if (!gpio_cells || size != sizeof(*gpio_cells) ||
+ *gpio_cells != of_gc->gpio_cells) {
+ pr_debug("%s: wrong #gpio-cells for %s\n",
+ np->full_name, gc->full_name);
+ goto err1;
+ }
+
+ /* Next phandle is at phandle cells + #gpio-cells */
+ i += sizeof(*gpio_phandle) / sizeof(u32) + *gpio_cells;
+ if (i >= nr_cells + 1) {
+ pr_debug("%s: insufficient gpio-spec length\n",
+ np->full_name);
+ goto err1;
+ }
+
+ if (gpio_index == index)
+ break;
+
+ of_gc = NULL;
+ of_node_put(gc);
+ }
+
+ if (!of_gc) {
+ ret = -ENOENT;
+ goto err0;
+ }
+
+ ret = of_gc->xlate(of_gc, np, gpio_spec);
+ if (ret < 0)
+ goto err1;
+
+ ret += of_gc->gc.base;
+err1:
+ of_node_put(gc);
+err0:
+ pr_debug("%s exited with status %d\n", __func__, ret);
+ return ret;
+}
+EXPORT_SYMBOL(of_get_gpio);
+
+/**
+ * of_gpio_simple_xlate - translate gpio_spec to the GPIO number
+ * @of_gc: pointer to the of_gpio_chip structure
+ * @np: device node of the GPIO chip
+ * @gpio_spec: gpio specifier as found in the device tree
+ *
+ * This is simple translation function, suitable for the most 1:1 mapped
+ * gpio chips. This function performs only one sanity check: whether gpio
+ * is less than ngpios (that is specified in the gpio_chip).
+ */
+int of_gpio_simple_xlate(struct of_gpio_chip *of_gc, struct device_node *np,
+ const void *gpio_spec)
+{
+ const u32 *gpio = gpio_spec;
+
+ if (*gpio > of_gc->gc.ngpio)
+ return -EINVAL;
+
+ return *gpio;
+}
+EXPORT_SYMBOL(of_gpio_simple_xlate);
+
+/* Should be sufficient for now, later we'll use dynamic bases. */
+#if defined(CONFIG_PPC32) || defined(CONFIG_SPARC32)
+#define GPIOS_PER_CHIP 32
+#else
+#define GPIOS_PER_CHIP 64
+#endif
+
+static int of_get_gpiochip_base(struct device_node *np)
+{
+ struct device_node *gc = NULL;
+ int gpiochip_base = 0;
+
+ while ((gc = of_find_all_nodes(gc))) {
+ if (!of_get_property(gc, "gpio-controller", NULL))
+ continue;
+
+ if (gc != np) {
+ gpiochip_base += GPIOS_PER_CHIP;
+ continue;
+ }
+
+ of_node_put(gc);
+
+ if (gpiochip_base >= ARCH_NR_GPIOS)
+ return -ENOSPC;
+
+ return gpiochip_base;
+ }
+
+ return -ENOENT;
+}
+
+/**
+ * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
+ * @np: device node of the GPIO chip
+ * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
+ *
+ * To use this function you should allocate and fill mm_gc with:
+ *
+ * 1) In the gpio_chip structure:
+ * - all the callbacks
+ *
+ * 2) In the of_gpio_chip structure:
+ * - gpio_cells
+ * - xlate callback (optional)
+ *
+ * 3) In the of_mm_gpio_chip structure:
+ * - save_regs callback (optional)
+ *
+ * If succeeded, this function will map bank's memory and will
+ * do all necessary work for you. Then you'll able to use .regs
+ * to manage GPIOs from the callbacks.
+ */
+int of_mm_gpiochip_add(struct device_node *np,
+ struct of_mm_gpio_chip *mm_gc)
+{
+ int ret = -ENOMEM;
+ struct of_gpio_chip *of_gc = &mm_gc->of_gc;
+ struct gpio_chip *gc = &of_gc->gc;
+
+ gc->label = kstrdup(np->full_name, GFP_KERNEL);
+ if (!gc->label)
+ goto err0;
+
+ mm_gc->regs = of_iomap(np, 0);
+ if (!mm_gc->regs)
+ goto err1;
+
+ gc->base = of_get_gpiochip_base(np);
+ if (gc->base < 0) {
+ ret = gc->base;
+ goto err1;
+ }
+
+ if (!of_gc->xlate)
+ of_gc->xlate = of_gpio_simple_xlate;
+
+ if (mm_gc->save_regs)
+ mm_gc->save_regs(mm_gc);
+
+ np->data = of_gc;
+
+ ret = gpiochip_add(gc);
+ if (ret)
+ goto err2;
+
+ /* We don't want to lose the node and its ->data */
+ of_node_get(np);
+
+ pr_debug("%s: registered as generic GPIO chip, base is %d\n",
+ np->full_name, gc->base);
+ return 0;
+err2:
+ np->data = NULL;
+ iounmap(mm_gc->regs);
+err1:
+ kfree(gc->label);
+err0:
+ pr_err("%s: GPIO chip registration failed with status %d\n",
+ np->full_name, ret);
+ return ret;
+}
+EXPORT_SYMBOL(of_mm_gpiochip_add);
diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
new file mode 100644
index 0000000..2ee97e9
--- /dev/null
+++ b/include/linux/of_gpio.h
@@ -0,0 +1,69 @@
+/*
+ * OF helpers for the GPIO API
+ *
+ * Copyright (c) 2007-2008 MontaVista Software, Inc.
+ *
+ * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
+ *
+ * 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.
+ */
+
+#ifndef __LINUX_OF_GPIO_H
+#define __LINUX_OF_GPIO_H
+
+#include <linux/errno.h>
+#include <asm/gpio.h>
+
+#ifdef CONFIG_OF_GPIO
+
+/*
+ * Generic OF GPIO chip
+ */
+struct of_gpio_chip {
+ struct gpio_chip gc;
+ int gpio_cells;
+ int (*xlate)(struct of_gpio_chip *of_gc, struct device_node *np,
+ const void *gpio_spec);
+};
+
+static inline struct of_gpio_chip *to_of_gpio_chip(struct gpio_chip *gc)
+{
+ return container_of(gc, struct of_gpio_chip, gc);
+}
+
+/*
+ * OF GPIO chip for memory mapped banks
+ */
+struct of_mm_gpio_chip {
+ struct of_gpio_chip of_gc;
+ void (*save_regs)(struct of_mm_gpio_chip *mm_gc);
+ void __iomem *regs;
+};
+
+static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
+{
+ struct of_gpio_chip *of_gc = to_of_gpio_chip(gc);
+
+ return container_of(of_gc, struct of_mm_gpio_chip, of_gc);
+}
+
+extern int of_get_gpio(struct device_node *np, int index);
+extern int of_mm_gpiochip_add(struct device_node *np,
+ struct of_mm_gpio_chip *mm_gc);
+extern int of_gpio_simple_xlate(struct of_gpio_chip *of_gc,
+ struct device_node *np,
+ const void *gpio_spec);
+#else
+
+/* Drivers may not strictly depend on the GPIO support, so let them link. */
+static inline int of_get_gpio(struct device_node *np, int index)
+{
+ return -ENOSYS;
+}
+
+#endif /* CONFIG_OF_GPIO */
+
+#endif /* __LINUX_OF_GPIO_H */
--
1.5.4.5
^ permalink raw reply related [flat|nested] 5+ messages in thread