[PATCH 01/11] [POWERPC] Implement support for the GPIO LIB API
Anton Vorontsov
avorontsov at ru.mvista.com
Mon Feb 4 04:09:51 EST 2008
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 at ru.mvista.com>
---
Documentation/powerpc/booting-without-of.txt | 58 ++++++++
arch/powerpc/Kconfig | 5 +
arch/powerpc/kernel/Makefile | 1 +
arch/powerpc/kernel/gpio.c | 200 ++++++++++++++++++++++++++
include/asm-powerpc/gpio.h | 118 +++++++++++++++
5 files changed, 382 insertions(+), 0 deletions(-)
create mode 100644 arch/powerpc/kernel/gpio.c
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 7b30798..ce77b47 100644
--- a/Documentation/powerpc/booting-without-of.txt
+++ b/Documentation/powerpc/booting-without-of.txt
@@ -64,6 +64,10 @@ 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
@@ -2858,6 +2862,60 @@ 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
+ ...>;
+
+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:
+
+ nand-flash at 1,0 {
+ compatible = "stmicro,NAND512W3A2BN6E", "fsl,upm-nand";
+ reg = <1 0 1>;
+ width = <1>;
+ upm = "A";
+ upm-addr-offset = <16>;
+ upm-cmd-offset = <8>;
+ gpios = <&qe_pio_e 18 0>;
+ wait-pattern;
+ wait-write;
+ };
+
+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 at 1400 {
+ #gpio-cells = <2>;
+ compatible = "fsl,qe-pario-bank";
+ reg = <0x1400 0x18>;
+ gpio-controller;
+ };
+
+ qe_pio_e: gpio-controller at 1460 {
+ #gpio-cells = <2>;
+ compatible = "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 9c44af3..f9ed22b 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/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 58dbfef..349a52d 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -65,6 +65,7 @@ obj-$(CONFIG_BOOTX_TEXT) += btext.o
obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_PPC_UDBG_16550) += legacy_serial.o udbg_16550.o
+obj-$(CONFIG_HAVE_GPIO_LIB) += gpio.o
pci64-$(CONFIG_PPC64) += pci_dn.o isa-bridge.o
obj-$(CONFIG_PCI) += pci_$(CONFIG_WORD_SIZE).o $(pci64-y) \
diff --git a/arch/powerpc/kernel/gpio.c b/arch/powerpc/kernel/gpio.c
new file mode 100644
index 0000000..64c567d
--- /dev/null
+++ b/arch/powerpc/kernel/gpio.c
@@ -0,0 +1,200 @@
+/*
+ * OF helpers for the GPIO API
+ *
+ * Copyright (c) 2007 MontaVista Software, Inc.
+ * Copyright (c) 2007 Anton Vorontsov <avorontsov at 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/io.h>
+#include <linux/of.h>
+#include <asm/prom.h>
+#include <asm/gpio.h>
+
+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;) {
+ 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++;
+ gpio_index++;
+ 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);
+ gpio_index++;
+ }
+
+ 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);
+
+static 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;
+}
+
+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 += ARCH_OF_GPIOS_PER_CHIP;
+ continue;
+ }
+
+ of_node_put(gc);
+
+ if (gpiochip_base >= ARCH_OF_GPIOS_END)
+ return -ENOSPC;
+
+ return gpiochip_base;
+ }
+
+ return -ENOENT;
+}
+
+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;
+
+ if (of_gc->gc.ngpio > ARCH_OF_GPIOS_PER_CHIP) {
+ ret = -ENOSPC;
+ goto err;
+ }
+
+ mm_gc->of_gc.gc.label = kstrdup(np->full_name, GFP_KERNEL);
+ if (!mm_gc->of_gc.gc.label)
+ goto err;
+
+ mm_gc->regs = of_iomap(np, 0);
+ if (!mm_gc->regs)
+ goto err1;
+
+ ret = of_get_gpiochip_base(np);
+ if (ret < 0)
+ goto err2;
+ mm_gc->of_gc.gc.base = ret;
+
+ if (!of_gc->xlate)
+ of_gc->xlate = of_gpio_simple_xlate;
+
+ if (mm_gc->save_regs)
+ mm_gc->save_regs(mm_gc);
+
+ np->data = &mm_gc->of_gc;
+
+ ret = gpiochip_add(&mm_gc->of_gc.gc);
+ if (ret)
+ goto err3;
+
+ /* 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, mm_gc->of_gc.gc.base);
+ return 0;
+err3:
+ np->data = NULL;
+err2:
+ iounmap(mm_gc->regs);
+err1:
+ kfree(mm_gc->of_gc.gc.label);
+err:
+ 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/asm-powerpc/gpio.h b/include/asm-powerpc/gpio.h
new file mode 100644
index 0000000..a97a93c
--- /dev/null
+++ b/include/asm-powerpc/gpio.h
@@ -0,0 +1,118 @@
+/*
+ * Generic GPIO API implementation for PowerPC.
+ *
+ * Copyright (c) 2007 MontaVista Software, Inc.
+ * Copyright (c) 2007 Anton Vorontsov <avorontsov at 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 <asm-generic/gpio.h>
+
+#ifdef CONFIG_HAVE_GPIO_LIB
+
+#define ARCH_OF_GPIOS_PER_CHIP 32
+#define ARCH_OF_GPIOS_BASE 0
+#define ARCH_OF_GPIOS_END (ARCH_OF_GPIOS_PER_CHIP * 7)
+#define ARCH_NON_OF_GPIOS_BASE ARCH_OF_GPIOS_END
+#define ARCH_NON_OF_GPIOS_END ARCH_NR_GPIOS
+
+#if ARCH_NON_OF_GPIOS_BASE >= ARCH_NON_OF_GPIOS_END
+#error "Default ARCH_NR_GPIOS isn't sufficient, define yours."
+#endif
+
+/*
+ * 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);
+}
+
+/*
+ * Not implemented, yet.
+ */
+static inline int gpio_to_irq(unsigned int gpio)
+{
+ return -ENOSYS;
+}
+
+static inline int irq_to_gpio(unsigned int irq)
+{
+ return -ENOSYS;
+}
+
+/*
+ * 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);
+};
+
+#define to_of_gpio_chip(x) container_of(x, 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;
+};
+
+#define to_of_mm_gpio_chip(x) container_of(to_of_gpio_chip(x), \
+ struct of_mm_gpio_chip, of_gc)
+
+/**
+ * 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.
+ */
+extern int of_get_gpio(struct device_node *np, int index);
+
+/**
+ * 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:
+ * a) all the callbacks
+ * b) ngpios (GPIOs per bank)
+ *
+ * 2) In the of_gpio_chip structure:
+ * a) gpio_cells
+ * b) xlate callback (optional)
+ *
+ * 3) In the of_mm_gpio_chip structure:
+ * a) 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.
+ */
+extern int of_mm_gpiochip_add(struct device_node *np,
+ struct of_mm_gpio_chip *mm_gc);
+
+#endif /* CONFIG_HAVE_GPIO_LIB */
+
+#endif /* __ASM_POWERPC_GPIO_H */
--
1.5.2.2
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