其原型为 int gpio_request(unsigned gpio, const char *label) 先说说其参数,gpio则为你要申请的哪一个管脚,label则是为其取一个名字。其具体实现如下
- int gpio_request(unsigned gpio, const char *label)
- {
- struct gpio_desc *desc;//这个自己看源码
- struct gpio_chip *chip;//这个自己看源码
- int status = -EINVAL;
- unsigned long flags;
- spin_lock_irqsave(&gpio_lock, flags);//屏蔽中断
- if (!gpio_is_valid(gpio))//判断是否有效,也就是参数的取值范围判断
- goto done;
- desc = &gpio_desc[gpio];
- //这个是关键gpio_desc为定义的一个全局的数组变量,这个函数的实值也就是,
- //用gpio_desc里面的一个变量来表示数组中的这个元素已经被申请了,而这个变量就是下面会看到的desc->flags。
- chip = desc->chip;//按理说这个这个全局的gpio_desc如果没有初始化的话,这个chip就为空了,随后就直接返回-EINVAL了。
- if (chip == NULL)如果不为空继续往下走
- goto done;
- if (!try_module_get(chip->owner))
- goto done;
- /* NOTE: gpio_request() can be called in early boot,
- * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
- */
- if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
- //这里测试并设置flags的第FLAG_REQUESTED位,如果没有被申请就返回该位的原值0,分析到这儿,也差不多满足了我的个人要求。
- desc_set_label(desc, label ? : "?");
- status = 0;
- } else {
- status = -EBUSY;
- module_put(chip->owner);
- goto done;
- }
- if (chip->request) {
- /* chip->request may sleep */
- spin_unlock_irqrestore(&gpio_lock, flags);
- status = chip->request(chip, gpio - chip->base);
- spin_lock_irqsave(&gpio_lock, flags);
- if (status < 0) {
- desc_set_label(desc, NULL);
- module_put(chip->owner);
- clear_bit(FLAG_REQUESTED, &desc->flags);
- }
- }
- done:
- if (status)
- pr_debug("gpio_request: gpio-%d (%s) status %d\n",
- gpio, label ? : "?", status);
- spin_unlock_irqrestore(&gpio_lock, flags);
- return status;
- }
davinci 平台:
- /*
- * TI DaVinci GPIO Support
- *
- * Copyright (c) 2006 David Brownell
- * Copyright (c) 2007, MontaVista Software, Inc. <source@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/errno.h>
- #include <linux/kernel.h>
- #include <linux/list.h>
- #include <linux/module.h>
- #include <linux/err.h>
- #include <linux/bitops.h>
- #include <asm/irq.h>
- #include <asm/io.h>
- #include <asm/hardware/clock.h>
- #include <asm/arch/irqs.h>
- #include <asm/arch/hardware.h>
- #include <asm/arch/gpio.h>
- #include <asm/arch/cpu.h>
- #include <asm/mach/irq.h>
- /*
- 该文件实现了gpio的各种应用功能和向内核注册gpio的中断例程等功能。
- 用户的驱动程序可调用gpio_request和gpio_free使用或释放该gpio,
- 可以调用gpio_direction_input和gpio_direction_output函数设置gpio输入输出方向,
- 调用gpio_get_value和gpio_set_value获取设置值。
- */
- static DEFINE_SPINLOCK(gpio_lock);
- /* 总共有DAVINCI_N_GPIO(71)个gpio引脚,故使用相应多的bit来记录这些引脚的使用状态 */
- static DECLARE_BITMAP(gpio_in_use, DAVINCI_N_GPIO);
- /*
- 申请一个gpio,其实就是检查该gpio是否空闲,如果空闲就可以使用并将该gpio相应的bit置位
- (在gpio_in_use中)。
- */
- int gpio_request(unsigned gpio, const char *tag)
- {
- if (gpio >= DAVINCI_N_GPIO)
- return -EINVAL;
- if (test_and_set_bit(gpio, gpio_in_use))
- return -EBUSY;
- return 0;
- }
- EXPORT_SYMBOL(gpio_request);
- /*
- 释放一个gpio,其实就是清除gpio相应的控制bit位(在gpio_in_use中)。
- */
- void gpio_free(unsigned gpio)
- {
- if (gpio >= DAVINCI_N_GPIO)
- return;
- clear_bit(gpio, gpio_in_use);
- }
- EXPORT_SYMBOL(gpio_free);
- /* 获得gpio_controller结构体指针,gpio_controller结构体是gpio的核心控制单元,里面包含
- gpio的设置和数据寄存器。该结构体和__gpio_to_controller函数在/include/asm-arm/
- arch-davinci/gpio.h中定义,具体如下:
- struct gpio_controller {
- u32 dir;
- u32 out_data;
- u32 set_data;
- u32 clr_data;
- u32 in_data;
- u32 set_rising;
- u32 clr_rising;
- u32 set_falling;
- u32 clr_falling;
- u32 intstat;
- };
- static inline struct gpio_controller *__iomem
- __gpio_to_controller(unsigned gpio)
- {
- void *__iomem ptr;
- if (gpio >= DAVINCI_N_GPIO)
- return NULL;
- if (gpio < 32)
- ptr = (void *__iomem)IO_ADDRESS(DAVINCI_GPIO_BASE + 0x10);
- else if (gpio < 64)
- ptr = (void *__iomem)IO_ADDRESS(DAVINCI_GPIO_BASE + 0x38);
- else if (gpio < 96)
- ptr = (void *__iomem)IO_ADDRESS(DAVINCI_GPIO_BASE + 0x60);
- else
- ptr = (void *__iomem)IO_ADDRESS(DAVINCI_GPIO_BASE + 0x88);
- return ptr;
- }
- 由上面的定义和ti的SPRUE25.pdf手册可以看出,__gpio_to_controller函数返回的是
- gpio_controller结构体到第一个成员dir的虚拟地址。获取了这个结构体指针后,
- 便可以控制相应的gpio了。dm644x共有71个gpio,
- 所以使用三个gpio_controller结构体控制,关于这个后面会由更详细的分析,
- */
- /* create a non-inlined version */
- static struct gpio_controller *__iomem gpio2controller(unsigned gpio)
- {
- return __gpio_to_controller(gpio);
- }
- /*
- 向某个gpio设置值,0或1。如果向gpio写1,则向set_data寄存器相应的位置1,如果写0,
- 则向clr_data寄存器相应的位置1.__gpio_mask函数在gpio.h中定义,定义如下,
- static inline u32 __gpio_mask(unsigned gpio)
- {
- return 1 << (gpio % 32);
- }
- 因为71个引脚由3个结构体控制,第一个控制前32个gpio,第二个控制次32个gpio,
- 最后一个控制剩余的7个gpio,故__gpio_mask函数的作用是找到在其相应控制结构体里的偏移数,
- 比如gpio34,那么其由第二个结构体控制,在这个机构体里的偏移是3(从0开始算,就是第二位)。
- 使用这个函数之前,必须确认该gpio设置成输出模式。
- */
- /*
- * Assuming the pin is muxed as a gpio output, set its output value.
- */
- void __gpio_set(unsigned gpio, int value)
- {
- struct gpio_controller *__iomem g = gpio2controller(gpio);
- // 设置gpio的值
- __raw_writel(__gpio_mask(gpio), value ? &g->set_data : &g->clr_data);
- }
- EXPORT_SYMBOL(__gpio_set);
- /*
- 通过读取in_data寄存器相应该gpio的位来读取gpio的值。
- 使用这个函数之前,必须确认该gpio设置成输入模式,否则获得到值不可预料。
- */
- /*
- * Read the pin's value (works even if it's set up as output);
- * returns zero/nonzero.
- *
- * Note that changes are synched to the GPIO clock, so reading values back
- * right after you've set them may give old values.
- */
- int __gpio_get(unsigned gpio)
- {
- struct gpio_controller *__iomem g = gpio2controller(gpio);
- /* 读取gpio的值,!!的目的是使得返回的值为0或1.*/
- return !!(__gpio_mask(gpio) & __raw_readl(&g->in_data));
- } }
- EXPORT_SYMBOL(__gpio_get);
- /*
- 通过dir寄存器相应该gpio的位来设置gpio输入输出方向,为0,则设置成输出,为1,则设置出输入。
- 该函数是设置成输入,故设置dir寄存器为1.
- 正如应为所说的,必须确认该引脚是作为gpio功能,而不是某个模块到功能,比如spi。通过PINMUX0
- 和PINMUX1两个寄存器来设置。
- */
- /*--------------------------------------------------------------------------*/
- /*
- * board setup code *MUST* set PINMUX0 and PINMUX1 as
- * needed, and enable the GPIO clock.
- */
- int gpio_direction_input(unsigned gpio)
- {
- struct gpio_controller *__iomem g = gpio2controller(gpio);
- u32 temp;
- u32 mask;
- if (!g)
- return -EINVAL;
- spin_lock(&gpio_lock);
- mask = __gpio_mask(gpio);
- temp = __raw_readl(&g->dir);
- temp |= mask; // 设置成1
- __raw_writel(temp, &g->dir); // 设置该gpio为输入
- spin_unlock(&gpio_lock);
- return 0;
- }
- EXPORT_SYMBOL(gpio_direction_input);
- /*
- 通过dir寄存器相应该gpio的位来设置gpio输入输出方向,为0,则设置成输出,为1,则设置出输入。
- 该函数是设置成输出,故设置dir寄存器为0.
- value参数用于选择gpio设置成输出后该gpio输出的值。
- */
- int gpio_direction_output(unsigned gpio, int value)
- {
- struct gpio_controller *__iomem g = gpio2controller(gpio);
- u32 temp;
- u32 mask;
- if (!g)
- return -EINVAL;
- spin_lock(&gpio_lock);
- mask = __gpio_mask(gpio);
- temp = __raw_readl(&g->dir);
- temp &= ~mask; // 设置成0
- //设置该gpio输出值
- __raw_writel(mask, value ? &g->set_data : &g->clr_data);
- __raw_writel(temp, &g->dir); // 设置gpio为输出
- spin_unlock(&gpio_lock);
- return 0;
- }
- EXPORT_SYMBOL(gpio_direction_output);
- /*
- 向gpio设置值,0或1。
- */
- void gpio_set_value(unsigned gpio, int value)
- {
- if (__builtin_constant_p(value)) {
- struct gpio_controller *__iomem g;
- u32 mask;
- if (gpio >= DAVINCI_N_GPIO)
- __error_inval_gpio();
- g = __gpio_to_controller(gpio);
- mask = __gpio_mask(gpio);
- if (value)
- __raw_writel(mask, &g->set_data); // 该gpio输出高
- else
- __raw_writel(mask, &g->clr_data); // 该gpio输出低
- return;
- }
- __gpio_set(gpio, value);
- }
- EXPORT_SYMBOL(gpio_set_value);
- /*
- 读取gpio的值,0或1.
- */
- int gpio_get_value(unsigned gpio)
- {
- struct gpio_controller *__iomem g;
- if (!__builtin_constant_p(gpio))/* 判断该gpio值是否为编译时常数,如果是常数,
- 函数返回 1,否则返回 0 */
- return __gpio_get(gpio);
- if (gpio >= DAVINCI_N_GPIO)
- return __error_inval_gpio();
- g = __gpio_to_controller(gpio);
-
- // 读取该gpio的值
- return !!(__gpio_mask(gpio) & __raw_readl(&g->in_data));
- }
- EXPORT_SYMBOL(gpio_get_value);
- /*
- * We expect irqs will normally be set up as input pins, but they can also be
- * used as output pins ... which is convenient for testing.
- *
- * NOTE: GPIO0..GPIO7 also have direct INTC hookups, which work in addition
- * to their GPIOBNK0 irq (but with a bit less overhead). But we don't have
- * a good way to hook those up ...
- *
- * All those INTC hookups (GPIO0..GPIO7 plus five IRQ banks) can also
- * serve as EDMA event triggers.
- */
- /*
- 禁止相应该irq的gpio的中断。每个gpio都可以作为中断的来源,其中gpio0-gpio7是独立的中断来源,
- 也就是分配独立的中断号,其他gpio则共用5个GPIOBNK中断线。其优先级可以在board-evm.c
- 中设置(已经介绍过)。在dm644x平台上,中断是电平边缘触发的,禁止中断其实就是既不设置
- 上升沿触发,也不设置下降沿触发。
- */
- static void gpio_irq_disable(unsigned irq)
- {
- struct gpio_controller *__iomem g = get_irq_chipdata(irq);
- u32 mask = __gpio_mask(irq_to_gpio(irq));
- __raw_writel(mask, &g->clr_falling); // 清除下降沿触发
- __raw_writel(mask, &g->clr_rising); // 清除上升沿触发
- }
- /*
- 中断使能。
- 在dm644x平台上,中断是电平边缘触发的,其实就是设置为上升沿或下降沿中断。
- */
- static void gpio_irq_enable(unsigned irq)
- {
- struct gpio_controller *__iomem g = get_irq_chipdata(irq);
- u32 mask = __gpio_mask(irq_to_gpio(irq));
- // 如果先前为下降沿中断,则使能为下降沿中断
- if (irq_desc[irq].status & IRQT_FALLING)
- __raw_writel(mask, &g->set_falling);
-
- // 如果先前为上升沿中断,则使能为上升沿中断
- if (irq_desc[irq].status & IRQT_RISING)
- __raw_writel(mask, &g->set_rising);
- }
- /*
- 设置中断类型。
- 在dm644x平台上,中断有上升沿和下降沿两种触发方式。
- */
- static int gpio_irq_type(unsigned irq, unsigned trigger)
- {
- struct gpio_controller *__iomem g = get_irq_chipdata(irq);
- u32 mask = __gpio_mask(irq_to_gpio(irq));
- if (trigger & ~(IRQT_FALLING | IRQT_RISING))
- return -EINVAL;
- irq_desc[irq].status &= ~IRQT_BOTHEDGE;
- irq_desc[irq].status |= trigger;
- __raw_writel(mask, (trigger & IRQT_FALLING)
- ? &g->set_falling : &g->clr_falling); // 设置为下降沿触发
- __raw_writel(mask, (trigger & IRQT_RISING)
- ? &g->set_rising : &g->clr_rising); // 设置为上升沿触发
- return 0;
- }
- /*
- 该结构体用于注册到所有irq的中断描述结构体中(struct irqdesc),
- 而所有中断描述结构体定义成一个全局数组irq_desc 。
- */
- static struct irqchip gpio_irqchip = {
- .unmask = gpio_irq_enable, /* 用于使能中断,
- 在enable_irq()等内核函数中会用到。*/
- .mask = gpio_irq_disable,/* 用于禁止中断,
- 在disable_irq()等内核函数中会用到。*/
- .type = gpio_irq_type, /* 用于设置中断类型,
- 在set_irq_type()内核函数中会用到。*/
- };
- /*
- 该函数将在下面的davinci_gpio_irq_setup中使用,将被注册到五个gpio bank中断的
- irq_desc结构中,目的是处理所有级联的gpio中断。所谓级联的中断, 就是指有n个中断
- 共用同一个中断线。
- 在dm644x平台中,除了gpio0-gpio7外,其他63个gpio都共用五个gpiobank中断线,在这里,
- gpio0-gpio7也被注册到gpiobank中断线,但实际上并不会使用,因为它们拥有自己的
- 中断线。其中,gpio0-gpio15共用IRQ_GPIOBNK0(56)中断线,gpio16-gpio31共用
- IRQ_GPIOBNK1(57)中断线,gpio32-gpio47共用IRQ_GPIOBNK2(58)中断线,
- gpio48-gpio63共用IRQ_GPIOBNK4(59)中断线,gpio64-gpio70共用
- IRQ_GPIOBNK5(60)中断线,
- 因为寄存器是32位的,所以实际上只有三组寄存器,第一组包含bank0和bank1,
- 也就是gpio0-gpio31,第二组包含bank2和bank3,也就是gpio32-gpio63,
- 第三组包含bank4和bank5,也就是gpio64-gpio70,剩余了25个位没有使用。
- */
- static void
- gpio_irq_handler(unsigned irq, struct irqdesc *desc, struct pt_regs *regs)
- {
- struct gpio_controller *__iomem g = get_irq_chipdata(irq);
- u32 mask = 0xffff;
- /* we only care about one bank */
- // 如果bank中断线是寄数,则说明该中断的中断状态位在INTSTATn寄存器的高16位
- if (irq & 1)
- mask <<= 16;
- /* temporarily mask (level sensitive) parent IRQ */
- desc->chip->ack(irq);// 该ack函数会在arch/arm/mach-davinci/irq.c中注册。
- while (1) {
- u32 status;
- struct irqdesc *gpio;
- int n;
- int res;
- /* ack any irqs */
- /*gpio中断发生后,硬件会在INTSTATn寄存器中置位相应位,
- 以备程序查询,确定是哪个gpio*/
- status = __raw_readl(&g->intstat) & mask;
- if (!status)
- break;
- __raw_writel(status, &g->intstat); // 向该位写1清除
- if (irq & 1)
- status >>= 16;
- /* now demux them to the right lowlevel handler */
- // 从下面的davinci_gpio_irq_setup函数可以看出来以下程序的运作。
- n = (int)get_irq_data(irq); // 获取该bank对应的第一个gpio号
- gpio = &irq_desc[n]; // 获取该bank第一个gpio号对应的中断描述符
- while (status) { // 该bank可能有多个gpio发生了中断
- res = ffs(status); // 获取第一个发生了中断的位(1-32)
- n += res; /* 获得该gpio的中断线(系统实际上只有64(0-63)个中断线,
- 但那些共用的gpio的中断也有自己的断描述符和中断线(从64开始),
- 仅仅是为了管理,不能通过request_irq()函数来申请。*/
- gpio += res; // 获得该gpio的中断描述符
-
- /* 调用下面注册的do_simple_IRQ例程
- 其又会调用用户通过request_irq()
- 注册的中断例程
- */
- desc_handle_irq(n - 1, gpio - 1, regs);
- status >>= res;
- }
- }
- desc->chip->unmask(irq); // 打开该irq中断线
- /* now it may re-trigger */
- }
- /*
- * NOTE: for suspend/resume, probably best to make a sysdev (and class)
- * with its suspend/resume calls hooking into the results of the set_wake()
- * calls ... so if no gpios are wakeup events the clock can be disabled,
- * with outputs left at previously set levels, and so that VDD3P3V.IOPWDN0
- * can be set appropriately for GPIOV33 pins.
- */
- /*
- 注册gpio中断例程到内核中,并初始化了一些寄存器。
- 该函数将会被board_evm.c(其浅析已经发表)中的evm_init()函数调用。具体调用过程如下:
- start_kernel()-->setup_arch()-->init_machine = mdesc->init_machine
- (init_machine是个全局函数指针变量,其指向的就是已经注册到机器描述符里evm_init());
- 调用函数指针init_machine()的例程是customize_machine(),其定义为
- arch_initcall(customize_machine),所以,接下来的调用过程是:
- start_kernel()-->do_basic_setup()-->do_initcalls()-->customize_machine()-->
- init_machine()(也就是evm_init())-->davinci_gpio_irq_setup。
- 从上可以看出经历了两个过程,才调用davinci_gpio_irq_setup例程来初始化gpio中断。
- */
- int __init davinci_gpio_irq_setup(void)
- {
- unsigned gpio, irq, bank, banks;
- struct clk *clk;
- clk = clk_get(NULL, "gpio"); // 获取时钟
- if (IS_ERR(clk)) {
- printk(KERN_ERR "Error %ld getting gpio clock?\n",
- PTR_ERR(clk));
- return 0;
- }
- clk_enable(clk); // 使能gpio时钟并打开该模块电源
- for (gpio = 0, irq = gpio_to_irq(0), bank = (cpu_is_davinci_dm355() ?
- IRQ_DM355_GPIOBNK0 : (cpu_is_davinci_dm6467() ?
- IRQ_DM646X_GPIOBNK0 : IRQ_GPIOBNK0)); // dm644x的IRQ_GPIOBNK0(56)
- gpio < DAVINCI_N_GPIO; bank++) { // dm644x的DAVINCI_N_GPIO(71)
- struct gpio_controller *__iomem g = gpio2controller(gpio);
- unsigned i;
- // 关该bank所有gpio的中断
- __raw_writel(~0, &g->clr_falling);
- __raw_writel(~0, &g->clr_rising);
- /* set up all irqs in this bank */
- // 同一个bank的所有gpio共用一个中断例程gpio_irq_handler
- set_irq_chained_handler(bank, gpio_irq_handler);
- set_irq_chipdata(bank, g);
- set_irq_data(bank, (void *)irq);
- for (i = 0; i < 16 && gpio < DAVINCI_N_GPIO;
- i++, irq++, gpio++) {
- set_irq_chip(irq, &gpio_irqchip); /* 注册用于gpio中断禁止、设能
- 和类型选择的回调例程 */
- set_irq_chipdata(irq, g); // 保存控制结构体(寄存器)的地址
- set_irq_handler(irq, do_simple_IRQ);/* 为每个gpio中断设置同一个中
- 断例程do_simple_IRQ*/
- set_irq_flags(irq, IRQF_VALID); // fiq中断有效
- }
- }
- /*
- 一个共用bank中断线的gpio中断发生后的大致的流程是:
- --> gpio_irq_handler --> do_simple_IRQ --> __do_irq -->
- action->handler(用户使用request_irq()注册的中断例程)
- */
- /* BINTEN -- per-bank interrupt enable. genirq would also let these
- * bits be set/cleared dynamically.
- */
- if (cpu_is_davinci_dm355())
- banks = 0x3f;
- else
- banks = 0x1f;
-
- // 向BINTEN寄存器写入0x1f(共5个位,每个位控制1个bank),打开所有的bank中断
- __raw_writel(banks, (void *__iomem)
- IO_ADDRESS(DAVINCI_GPIO_BASE + 0x08));
- printk(KERN_INFO "DaVinci: %d gpio irqs\n", irq - gpio_to_irq(0));
- return 0;
- }
-
- gpio.h
- /*
- * TI DaVinci GPIO Support
- *
- * Copyright (c) 2006 David Brownell
- * Copyright (c) 2007, MontaVista Software, Inc. <source@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 __DAVINCI_GPIO_H
- #define __DAVINCI_GPIO_H
- /*
- * basic gpio routines
- *
- * board-specific init should be done by arch/.../.../board-XXX.c (maybe
- * initializing banks together) rather than boot loaders; kexec() won't
- * go through boot loaders.
- *
- * the gpio clock will be turned on when gpios are used, and you may also
- * need to pay attention to PINMUX0 and PINMUX1 to be sure those pins are
- * used as gpios, not with other peripherals.
- *
- * GPIOs are numbered 0..(DAVINCI_N_GPIO-1). For documentation, and maybe
- * for later updates, code should write GPIO(N) or:
- * - GPIOV18(N) for 1.8V pins, N in 0..53; same as GPIO(0)..GPIO(53)
- * - GPIOV33(N) for 3.3V pins, N in 0..17; same as GPIO(54)..GPIO(70)
- *
- * For GPIO IRQs use gpio_to_irq(GPIO(N)) or gpio_to_irq(GPIOV33(N)) etc
- * for now, that's != GPIO(N)
- */
- #define GPIO(X) (X) /* 0 <= X <= 70 */
- #define GPIOV18(X) (X) /* 1.8V i/o; 0 <= X <= 53 */
- #define GPIOV33(X) ((X)+54) /* 3.3V i/o; 0 <= X <= 17 */
- /*
- 寄存器都是32位到,每位对应一个gpio。
- */
- struct gpio_controller {
- u32 dir; // gpio方向设置寄存器
- u32 out_data; // gpio设置为输出时,表示输出状态(0或1)
- u32 set_data; // gpio设置为输出时,用于输出高电平
- u32 clr_data; // gpio设置为输出时,用于输出低电平
- u32 in_data; // gpio设置为输入时,用于读取输入值
- u32 set_rising; // gpio中断上升沿触发设置
- u32 clr_rising; // gpio中断上升沿触发清除
- u32 set_falling; // gpio中断下降沿触发设置
- u32 clr_falling; // gpio中断下降沿触发清除
- u32 intstat; // gpio中断状态位,由硬件设置,可读取,写1时清除。
- };
- /* The __gpio_to_controller() and __gpio_mask() functions inline to constants
- * with constant parameters; or in outlined code they execute at runtime.
- *
- * You'd access the controller directly when reading or writing more than
- * one gpio value at a time, and to support wired logic where the value
- * being driven by the cpu need not match the value read back.
- *
- * These are NOT part of the cross-platform GPIO interface
- */
- static inline struct gpio_controller *__iomem
- __gpio_to_controller(unsigned gpio)
- {
- void *__iomem ptr;
- if (gpio >= DAVINCI_N_GPIO)
- return NULL;
- if (gpio < 32)
- ptr = (void *__iomem)IO_ADDRESS(DAVINCI_GPIO_BASE + 0x10);
- else if (gpio < 64)
- ptr = (void *__iomem)IO_ADDRESS(DAVINCI_GPIO_BASE + 0x38);
- else if (gpio < 96)
- ptr = (void *__iomem)IO_ADDRESS(DAVINCI_GPIO_BASE + 0x60);
- else
- ptr = (void *__iomem)IO_ADDRESS(DAVINCI_GPIO_BASE + 0x88);
- return ptr;
- }
- static inline u32 __gpio_mask(unsigned gpio)
- {
- return 1 << (gpio % 32);
- }
- /* The get/set/clear functions will inline when called with constant
- * parameters, for low-overhead bitbanging. Illegal constant parameters
- * cause link-time errors.
- *
- * Otherwise, calls with variable parameters use outlined functions.
- */
- extern int __error_inval_gpio(void);
- extern void __gpio_set(unsigned gpio, int value);
- extern int __gpio_get(unsigned gpio);
- /* Returns zero or nonzero; works for gpios configured as inputs OR
- * as outputs.
- *
- * NOTE: changes in reported values are synchronized to the GPIO clock.
- * This is most easily seen after calling gpio_set_value() and then immediatly
- * gpio_get_value(), where the gpio_get_value() would return the old value
- * until the GPIO clock ticks and the new value gets latched.
- */
- extern int gpio_get_value(unsigned gpio);
- extern void gpio_set_value(unsigned gpio, int value);
- /* powerup default direction is IN */
- extern int gpio_direction_input(unsigned gpio);
- extern int gpio_direction_output(unsigned gpio, int value);
- #include <asm-generic/gpio.h> /* cansleep wrappers */
- extern int gpio_request(unsigned gpio, const char *tag);
- extern void gpio_free(unsigned gpio);
- static inline int gpio_to_irq(unsigned gpio)
- {
- return DAVINCI_N_AINTC_IRQ + gpio;
- }
- static inline int irq_to_gpio(unsigned irq)
- {
- return irq - DAVINCI_N_AINTC_IRQ;
- }
- #endif /* __DAVINCI_GPIO_H */
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