1 /* 2 * Copyright (C) 2012 Vikram Narayananan 3 * <vikram186@gmail.com> 4 * 5 * See file CREDITS for list of people who contributed to this 6 * project. 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License as 10 * published by the Free Software Foundation; either version 2 of 11 * the License, or (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 */ 18 19 #include <common.h> 20 #include <asm/gpio.h> 21 #include <asm/io.h> 22 23 inline int gpio_is_valid(unsigned gpio) 24 { 25 return (gpio < BCM2835_GPIO_COUNT); 26 } 27 28 int gpio_request(unsigned gpio, const char *label) 29 { 30 return !gpio_is_valid(gpio); 31 } 32 33 int gpio_free(unsigned gpio) 34 { 35 return 0; 36 } 37 38 int gpio_direction_input(unsigned gpio) 39 { 40 struct bcm2835_gpio_regs *reg = 41 (struct bcm2835_gpio_regs *)BCM2835_GPIO_BASE; 42 unsigned val; 43 44 val = readl(®->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]); 45 val &= ~(BCM2835_GPIO_FSEL_MASK << BCM2835_GPIO_FSEL_SHIFT(gpio)); 46 val |= (BCM2835_GPIO_INPUT << BCM2835_GPIO_FSEL_SHIFT(gpio)); 47 writel(val, ®->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]); 48 49 return 0; 50 } 51 52 int gpio_direction_output(unsigned gpio, int value) 53 { 54 struct bcm2835_gpio_regs *reg = 55 (struct bcm2835_gpio_regs *)BCM2835_GPIO_BASE; 56 unsigned val; 57 58 gpio_set_value(gpio, value); 59 60 val = readl(®->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]); 61 val &= ~(BCM2835_GPIO_FSEL_MASK << BCM2835_GPIO_FSEL_SHIFT(gpio)); 62 val |= (BCM2835_GPIO_OUTPUT << BCM2835_GPIO_FSEL_SHIFT(gpio)); 63 writel(val, ®->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]); 64 65 return 0; 66 } 67 68 int gpio_get_value(unsigned gpio) 69 { 70 struct bcm2835_gpio_regs *reg = 71 (struct bcm2835_gpio_regs *)BCM2835_GPIO_BASE; 72 unsigned val; 73 74 val = readl(®->gplev[BCM2835_GPIO_COMMON_BANK(gpio)]); 75 76 return (val >> BCM2835_GPIO_COMMON_SHIFT(gpio)) & 0x1; 77 } 78 79 int gpio_set_value(unsigned gpio, int value) 80 { 81 struct bcm2835_gpio_regs *reg = 82 (struct bcm2835_gpio_regs *)BCM2835_GPIO_BASE; 83 u32 *output_reg = value ? reg->gpset : reg->gpclr; 84 85 writel(1 << BCM2835_GPIO_COMMON_SHIFT(gpio), 86 &output_reg[BCM2835_GPIO_COMMON_BANK(gpio)]); 87 88 return 0; 89 } 90