GPIO Configuration for IMX6 processors

How GPIO is configured for Freescale IMX6 processors

Turn from:

Http://zzjlzx.blog.chinaunix.net/uid-9688646-id-5206540.html

In Linux or Android, if we want to configure a Freescale IMX6 processor's Gpio pin, such as the gpio_19 pin, then this: [CPP] view plain copy #define Mx6q_pad_ Gpio_19__gpio_4_5 \ (_mx6q_pad_gpio_19__gpio_4_5 | Mux_pad_ctrl (No_pad_ctrl))

Where _mx6q_pad_gpio_19__gpio_4_5 is defined as: [CPP] view plain copy #define _MX6Q_PAD_GPIO_19__GPIO_4_5 \ IO Mux_pad (0x0624, 0x0254, 5, 0x0000, 0, 0)

This IOMUX_PAD macro is a key macro that defines Gpio, and is prototyped as: [CPP] view plain copy #define IOMUX_PAD (_pad_ctrl_ofs, _mux_ctrl_ofs, _mux_mode , _sel_input_ofs, _sel_input, _pad_ctrl)

The IOMUX_PAD macro has 6 parameters, and each parameter means:

Parameters	meaning
_pad_ctrl_ofs	Offset address of the control register (16 binary)
_mux_ctrl_ofs	Offset address (16 binary) of the MUX Control register for selecting the PIN function
_mux_mode	MUX mode, bit0~3, range 0~7
_select_input_ofs	Select_input Register offset address (16 binary)
_select_input	Daisy chain mode, bit0~1, range 0~3
_pad_ctrl	Bits to BES set in register _pad_ctrl_ofs for configuration selection

The specific meaning should be combined with the contents of the IMX6 data sheet "Chapter Imoux Controller (IOMUXC)".

The following is a description of gpio_19 this PIN configuration:

1, _pad_ctrl_ofs

Find the Data sheet page 2433:

From the image above: _pad_ctrl_ofs = 0x624

2, _mux_ctrl_ofs, _mux_mode

Find the contents of page 2055 of the data sheet:

As shown above, the _mux_ctrl_ofs value is 0x254,_mux_mode range of 000~110

Only _mux_mode = 0 o'clock, _select_input_ofs and _select_input are valid, while the remaining _select_input_ofs and _select_input are 0. 3, _select_input_of, _select_input

When _mux_mode = 0 o'clock, the value of _select_input_ofs should be referenced in the Data sheet page 2654:

At this time _select_input_ofs=0x8e8,_select_input=0x1

4, _pad_ctrl

_pad_ctrl General value is 0

In summary, the GPIO_19 configuration macro is defined as follows:[CPP] View Plain copy #define _mx6q_pad_gpio_19__kpp_col_5             \          Iomux_pad (0x0624, 0x0254, 0, 0x08e8, 1, 0)   #define _mx6q _pad_gpio_19__enet_1588_event0_out     \          Iomux_pad (0x0624, 0x0254, 1, 0x0000, 0, 0)   #define _mx6q_pad_gpio_19__spdif_out1     & nbsp;     \          iomux_pad (0x0624, 0x0254, 2, 0x0000 , 0, 0)   #define _mx6q_pad_gpio_19__ccm_clko         \           Iomux_pad (0x0624, 0x0254, 3, 0x0000, 0, 0)   #define _MX6Q_PAD_GPIO_19__ ecspi1_rdy           \           Iomux_pad (0x0624, 0x0254, 4, 0x0000, 0, 0)   #define _mx6q_pad_gpio_19__gpio_4_5         \          iomux_ PAD (0x0624, 0x0254, 5, 0x0000, 0, 0)   #define _mx6q_pad_gpio_19__enet_tx_er      & nbsp;    \          iomux_pad (0x0624, 0x0254, 6, 0x0000, 0, 0) & nbsp #define _mx6q_pad_gpio_19__src_int_boot         \           Iomux_pad (0x0624, 0x0254, 7, 0x0000, 0, 0)  

The above macros define the Linux source code from imx6 arm/arch/palt-mxc/include/mach/iomux-mx6q.h