android13/u-boot/examples/standalone/README_rkspi.md

127 lines
2.6 KiB
Markdown

# RK SPI Standalone Bin
This is the readme for the Das U-Boot standalone program rkspi
How To Use
------------------------
### Compile
1.Define the standalone load address in includes/configs/rkxxxxx_common.h
```shell
#define CONFIG_STANDALONE_LOAD_ADDR 0x40000000
```
2.Enable rkspi in defconfig
```
CONFIG_ROCKCHIP_SPI=y
```
### Setting SPI hardware
1.Setting the iomux and spiclk through:
- u-boot shell command
- define it in rkspi.c spi_hw_init
Note:
- spiclk is the clock for spi controller, output to IO after internal frequency division of the controller.
### Load And Executable
1. load the bin by serial or tftp, take tftp as example:
```shell
setenv ipaddr 172.16.12.157
setenv serverip 172.16.12.167
tftp 0x40000000 rkspi.bin # 0x40000000 is define by CONFIG_STANDALONE_LOAD_ADDR
```
2. execute it
```shell
go 0x40000000 # 0x40000000 is define by CONFIG_STANDALONE_LOAD_ADDR
```
## Abort Codes
### Introduction
```c
int rockchip_spi_probe(u8 bus, uintptr_t base_addr, u32 rsd, u32 clock_div, u32 mode);
```
- bus: spi bus
- base_addr: spi register base address
- rsd: read sample clock shift with spiclk which is controller working rate
- clock_div: internal frequency division of the controller
- mode: spi mode, support:
```c
#define SPI_CPHA BIT(0) /* clock phase */
#define SPI_CPOL BIT(1) /* clock polarity */
#define SPI_MODE_0 (0 | 0) /* (original MicroWire) */
#define SPI_MODE_1 (0 | SPI_CPHA)
#define SPI_MODE_2 (SPI_CPOL | 0)
#define SPI_MODE_3 (SPI_CPOL | SPI_CPHA)
```
```c
int rockchip_spi_claim_bus(u8 bus);
```
- bus: spi bus
```c
void rockchip_spi_release_bus(u8 bus);
```
- bus: spi bus
```c
int rockchip_spi_xfer(u8 bus, u8 cs, unsigned int bitlen, const void *dout, void *din, unsigned long flags);
```
- bus: spi bus
- cs: spi cs
- bitlen: the transfer length in bits
- dout: write buffer (if exits)
- din: read buffer (if exits), if the dout and din both defined, spi work in duplex mode
- flags: operation chip select, support:
```c
#define SPI_XFER_BEGIN BIT(0) /* Assert CS before transfer */
#define SPI_XFER_END BIT(1) /* Deassert CS after transfer */
#define SPI_XFER_ONCE (SPI_XFER_BEGIN | SPI_XFER_END)
```
```c
int rockchip_spi_write_then_read(u8 bus, u8 cs,
const u8 *opcode, size_t n_opcode,
const u8 *txbuf, u8 *rxbuf, size_t n_buf);
```
- bus: spi bus
- cs: spi cs
- opcode: command code
- n_opcode: the numbers of command code in bytes
- txbuf: write buffer (if exits)
- rxbuf: read buffer (if exits), if the dout and din both defined, spi work in duplex mode
- n_buf: the transfer length in bytes
### Demo
Is right in the main function of rkspi.