/******************************************************************************* * I.MX6 U-boot GPIO hacking * 说明： * 本文主要记录I.MX6 U-boot是如何设置GPIO口输入输出的，主要是考虑到这个阶段 * 并没有像Linux内核中的gpio_request一系列函数使用。 * * 2016-3-7 深圳 南山平山村 曾剑锋 ******************************************************************************/ cat bootable/bootloader/uboot-imx/board/freescale/mx6q_sabresd/mx6q_sabresd.c ...... #ifdef CONFIG_LCD void lcd_enable(void) { ...... mxc_iomux_v3_setup_pad(MX6DL_PAD_SD1_DAT2__GPIO_1_19); ---+ reg = readl(GPIO1_BASE_ADDR + GPIO_GDIR); ---*---------------+ reg |= (1 << 19); | | writel(reg, GPIO1_BASE_ADDR + GPIO_GDIR); | | | | reg = readl(GPIO1_BASE_ADDR + GPIO_DR); | | reg &= ~(1 << 19); | | writel(reg, GPIO1_BASE_ADDR + GPIO_DR); | | ...... | | } | | ...... | | | | #define MX6DL_PAD_SD1_DAT2__GPIO_1_19 <---+ \ | IOMUX_PAD(0x06D4, 0x02EC, 5, 0x0000, 0, NO_PAD_CTRL) | | | | /* | | * configures a single pad in the iomuxer | | */ | | int mxc_iomux_v3_setup_pad(iomux_v3_cfg_t pad) <---+ | { | u32 mux_ctrl_ofs = (pad & MUX_CTRL_OFS_MASK) >> MUX_CTRL_OFS_SHIFT; | u32 mux_mode = (pad & MUX_MODE_MASK) >> MUX_MODE_SHIFT; | u32 sel_input_ofs = (pad & MUX_SEL_INPUT_OFS_MASK) >> MUX_SEL_INPUT_OFS_SHIFT; | u32 sel_input = (pad & MUX_SEL_INPUT_MASK) >> MUX_SEL_INPUT_SHIFT; | u32 pad_ctrl_ofs = (pad & MUX_PAD_CTRL_OFS_MASK) >> MUX_PAD_CTRL_OFS_SHIFT; | u32 pad_ctrl = (pad & MUX_PAD_CTRL_MASK) >> MUX_PAD_CTRL_SHIFT; | | if (mux_ctrl_ofs) | __raw_writel(mux_mode, base + mux_ctrl_ofs); | | if (sel_input_ofs) | __raw_writel(sel_input, base + sel_input_ofs); | | if (!(pad_ctrl & NO_PAD_CTRL) && pad_ctrl_ofs) | __raw_writel(pad_ctrl, base + pad_ctrl_ofs); | | return 0; | } | EXPORT_SYMBOL(mxc_iomux_v3_setup_pad); | | | /** | * 1. 参考文档： | * i.MX 6Dual/6Quad Multimedia Applications Processor Reference Manual | * 2. 30.4 Programmable Registers | * +------------------------------------------------------+ | * | GPIO memory map | | * +-----------+-------------------------------+----------+ | * | Absolute | Register name | Section/ | | * | address | | page | | * | (hex) | | | | * +-----------+-------------------------------+----------+ | * | 0209_C000 | GPIO data register (GPIO1_DR) | 30.4.1/ | | * | | | | | * +-----------+-------------------------------+----------+ | * 3. GPIO1_BASE_ADDR = 0x1C000 + 0x80000 + 0x02000000 | * GPIO1_BASE_ADDR = 0x0209C000 | */ | #define GPIO1_BASE_ADDR (AIPS1_OFF_BASE_ADDR + 0x1C000) <--------+ #define AIPS1_OFF_BASE_ADDR (ATZ1_BASE_ADDR + 0x80000) | #define ATZ1_BASE_ADDR AIPS1_ARB_BASE_ADDR | #define AIPS1_ARB_BASE_ADDR 0x02000000 | | #define GPIO_GDIR 0x04 <--------+ #define GPIO_DR 0x00