1.背景介绍
近期板卡上开始使用中航光电的光模块，查阅资料发现这些光模块都可以通过I2C来获取状态信息并进行开关控制，描述如下，其中需要特别注意的是所有光模块的读写I2C地址都是一样的，不可以挂在一根总线上，要么分别单独控制，要么通过交换芯片切换控制。
为了实现这一点，可以考虑通过zynq的I2C控制器来对光模块进行操作。由于ZYNQ PS部分的I2C控制器只有两个，当光模块数量超过2个时使用PL部分的I2C IP核来实现较为简单。
2.硬件参考设计
这里使用了6个ZYNQ PL部分的I2C核来控制6个外接光模块
每个IP核出一个中断接入PL-PS的中断引脚，这里使用了一个组合器
3.devicetree设置
硬件产生后导出设备树后，能看到PL部分由I2C控制器，需要修改为如下：
把clock-names改成如图所示，加上interrupt-names这一行，最后是添加从设备，这里写2其实并不是i2c设备地址为2，只是为了把设备挂上，随便什么地址都可以。完整的设备树信息如下：
/dts-v1/;
/ {
#address-cells = <0x1>;
#size-cells = <0x1>;
compatible = "xlnx,zynq-7000";
cpus {
#address-cells = <0x1>;
#size-cells = <0x0>;
cpu@0 {
compatible = "arm,cortex-a9";
device_type = "cpu";
reg = <0x0>;
clocks = <0x1 0x3>;
clock-latency = <0x3e8>;
cpu0-supply = <0x2>;
operating-points = <0xa4cb8 0xf4240 0x5265c 0xf4240>;
};
cpu@1 {
compatible = "arm,cortex-a9";
device_type = "cpu";
reg = <0x1>;
clocks = <0x1 0x3>;
};
};
fpga-full {
compatible = "fpga-region";
fpga-mgr = <0x3>;
#address-cells = <0x1>;
#size-cells = <0x1>;
ranges;
};
pmu@f8891000 {
compatible = "arm,cortex-a9-pmu";
interrupts = <0x0 0x5 0x4 0x0 0x6 0x4>;
interrupt-parent = <0x4>;
reg = <0xf8891000 0x1000 0xf8893000 0x1000>;
};
fixedregulator {
compatible = "regulator-fixed";
regulator-name = "VCCPINT";
regulator-min-microvolt = <0xf4240>;
regulator-max-microvolt = <0xf4240>;
regulator-boot-on;
regulator-always-on;
linux,phandle = <0x2>;
phandle = <0x2>;
};
amba {
u-boot,dm-pre-reloc;
compatible = "simple-bus";
#address-cells = <0x1>;
#size-cells = <0x1>;
interrupt-parent = <0x4>;
ranges;
adc@f8007100 {
compatible = "xlnx,zynq-xadc-1.00.a";
reg = <0xf8007100 0x20>;
interrupts = <0x0 0x7 0x4>;
interrupt-parent = <0x4>;
clocks = <0x1 0xc>;
xlnx,channels {
#address-cells = <0x1>;
#size-cells = <0x0>;
channel@0 {
reg = <0x0>;
};
channel@1 {
reg = <0x1>;
};
channel@2 {
reg = <0x2>;
};
channel@3 {
reg = <0x3>;
};
channel@4 {
reg = <0x4>;
};
channel@5 {
reg = <0x5>;
};
channel@6 {
reg = <0x6>;
};
channel@7 {
reg = <0x7>;
};
channel@8 {
reg = <0x8>;
};
channel@9 {
reg = <0x9>;
};
channel@a {
reg = <0xa>;
};
channel@b {
reg = <0xb>;
};
channel@c {
reg = <0xc>;
};
channel@d {
reg = <0xd>;
};
channel@e {
reg = <0xe>;
};
channel@f {
reg = <0xf>;
};
channel@10 {
reg = <0x10>;
};
};
};
gpio@e000a000 {
compatible = "xlnx,zynq-gpio-1.0";
#gpio-cells = <0x2>;
clocks = <0x1 0x2a>;
gpio-controller;
interrupt-controller;
#interrupt-cells = <0x2>;
interrupt-parent = <0x4>;
interrupts = <0x0 0x14 0x4>;
reg = <0xe000a000 0x1000>;
};
i2c@e0004000 {
compatible = "cdns,i2c-r1p10-slave";
status = "okay";
clocks = <0x1 0x26>;
interrupt-parent = <0x4>;
interrupts = <0x0 0x19 0x4>;
reg = <0xe0004000 0x1000>;
#address-cells = <0x1>;
#size-cells = <0x0>;
clock-frequency = <0x61a80>;
};
i2c@e0005000 {
compatible = "cdns,i2c-r1p10-slave";
status = "okay";
clocks = <0x1 0x27>;
interrupt-parent = <0x4>;
interrupts = <0x0 0x30 0x4>;
reg = <0xe0005000 0x1000>;
#address-cells = <0x1>;
#size-cells = <0x0>;
clock-frequency = <0x61a80>;
};
interrupt-controller@f8f01000 {
compatible = "arm,cortex-a9-gic";
#interrupt-cells = <0x3>;
interrupt-controller;
reg = <0xf8f01000 0x1000 0xf8f00100 0x100>;
num_cpus = <0x2>;
num_interrupts = <0x60>;
linux,phandle = <0x4>;
phandle = <0x4>;
};
cache-controller@f8f02000 {
compatible = "arm,pl310-cache";
reg = <0xf8f02000 0x1000>;
interrupts = <0x0 0x2 0x4>;
arm,data-latency = <0x3 0x2 0x2>;
arm,tag-latency = <0x2 0x2 0x2>;
cache-unified;
cache-level = <0x2>;
};
memory-controller@f8006000 {
compatible = "xlnx,zynq-ddrc-a05";
reg = <0xf8006000 0x1000>;
};
ocmc@f800c000 {
compatible = "xlnx,zynq-ocmc-1.0";
interrupt-parent = <0x4>;
interrupts = <0x0 0x3 0x4>;
reg = <0xf800c000 0x1000>;
};
serial@e0000000 {
compatible = "xlnx,xuartps", "cdns,uart-r1p8";
status = "okay";
clocks = <0x1 0x17 0x1 0x28>;
clock-names = "uart_clk", "pclk";
reg = <0xe0000000 0x1000>;
interrupts = <0x0 0x1b 0x4>;
device_type = "serial";
port-number = <0x4>;
};
spi@e000d000 {
clock-names = "ref_clk", "pclk";
clocks = <0x1 0xa 0x1 0x2b>;
compatible = "xlnx,zynq-qspi-1.0";
status = "okay";
interrupt-parent = <0x4>;
interrupts = <0x0 0x13 0x4>;
reg = <0xe000d000 0x1000>;
#address-cells = <0x1>;
#size-cells = <0x0>;
is-dual = <0x1>;
num-cs = <0x1>;
};
ethernet@e000b000 {
compatible = "xlnx,ps7-ethernet-1.00.a";
reg = <0xe000b000 0x1000>;
status = "okay";
interrupts = <0x0 0x16 0x4>;
clocks = <0x1 0xd 0x1 0x1e>;
clock-names = "ref_clk", "aper_clk";
#address-cells = <0x1>;
#size-cells = <0x0>;
enet-reset = <0x4 0x2f 0x0>;
#local-mac-address = [00 0b 35 11 12 00];
local-mac-address = [00 0b 44 00 3e 16];
phy-mode = "rgmii";
phy-handle = <0x7>;
xlnx,eth-mode = <0x1>;
xlnx,has-mdio = <0x1>;
xlnx,ptp-enet-clock = <0x69f6bcb>;
mdio {
#address-cells = <0x1>;
#size-cells = <0x0>;
phy@2 {
compatible = "marvell,88e1111";
device_type = "ethernet-phy";
reg = <0x2>;
linux,phandle = <0x7>;
phandle = <0x7>;
};
};
};
ethernet@e000c000 {
compatible = "xlnx,ps7-ethernet-1.00.b";
reg = <0xe000c000 0x1000>;
status = "okay";
interrupts = <0x0 0x2d 0x4>;
clocks = <0x1 0xe 0x1 0x1f>;
clock-names = "ref_clk", "aper_clk";
#address-cells = <0x1>;
#size-cells = <0x0>;
enet-reset = <0x4 0x2f 0x0>;
local-mac-address = [00 0b 36 11 11 00];
phy-mode = "rgmii";
phy-handle = <0x8>;
xlnx,eth-mode = <0x1>;
xlnx,has-mdio = <0x1>;
xlnx,ptp-enet-clock = <0x69f6bcb>;
mdio {
#address-cells = <0x1>;
#size-cells = <0x0>;
phy@1 {
compatible = "marvell,88e1111";
device_type = "ethernet-phy";
reg = <0x1>;
linux,phandle = <0x8>;
phandle = <0x8>;
};
};
};
slcr@f8000000 {
u-boot,dm-pre-reloc;
#address-cells = <0x1>;
#size-cells = <0x1>;
compatible = "xlnx,zynq-slcr", "syscon", "simple-mfd";
reg = <0xf8000000 0x1000>;
ranges;
linux,phandle = <0x5>;
phandle = <0x5>;
clkc@100 {
u-boot,dm-pre-reloc;
#clock-cells = <0x1>;
compatible = "xlnx,ps7-clkc";
fclk-enable = <0x7>;
clock-output-names = "armpll", "ddrpll", "iopll", "cpu_6or4x", "cpu_3or2x", "cpu_2x", "cpu_1x", "ddr2x", "ddr3x", "dci", "lqspi", "smc", "pcap", "gem0", "gem1", "fclk0", "fclk1", "fclk2", "fclk3", "can0", "can1", "sdio0", "sdio1", "uart0", "uart1", "spi0", "spi1", "dma", "usb0_aper", "usb1_aper", "gem0_aper", "gem1_aper", "sdio0_aper", "sdio1_aper", "spi0_aper", "spi1_aper", "can0_aper", "can1_aper", "i2c0_aper", "i2c1_aper", "uart0_aper", "uart1_aper", "gpio_aper", "lqspi_aper", "smc_aper", "swdt", "dbg_trc", "dbg_apb";
reg = <0x100 0x100>;
ps-clk-frequency = <0x2faf080>;
linux,phandle = <0x1>;
phandle = <0x1>;
};
rstc@200 {
compatible = "xlnx,zynq-reset";
reg = <0x200 0x48>;
#reset-cells = <0x1>;
syscon = <0x5>;
};
pinctrl@700 {
compatible = "xlnx,pinctrl-zynq";
reg = <0x700 0x200>;
syscon = <0x5>;
};
};
dmac@f8003000 {
compatible = "arm,pl330", "arm,primecell";
reg = <0xf8003000 0x1000>;
interrupt-parent = <0x4>;
interrupt-names = "abort", "dma0", "dma1", "dma2", "dma3", "dma4", "dma5", "dma6", "dma7";
interrupts = <0x0 0xd 0x4 0x0 0xe 0x4 0x0 0xf 0x4 0x0 0x10 0x4 0x0 0x11 0x4 0x0 0x28 0x4 0x0 0x29 0x4 0x0 0x2a 0x4 0x0 0x2b 0x4>;
#dma-cells = <0x1>;
#dma-channels = <0x8>;
#dma-requests = <0x4>;
clocks = <0x1 0x1b>;
clock-names = "apb_pclk";
};
devcfg@f8007000 {
compatible = "xlnx,zynq-devcfg-1.0";
interrupt-parent = <0x4>;
interrupts = <0x0 0x8 0x4>;
reg = <0xf8007000 0x100>;
clocks = <0x1 0xc 0x1 0xf 0x1 0x10 0x1 0x11 0x1 0x12>;
clock-names = "ref_clk", "fclk0", "fclk1", "fclk2", "fclk3";
syscon = <0x5>;
linux,phandle = <0x3>;
phandle = <0x3>;
};
efuse@f800d000 {
compatible = "xlnx,zynq-efuse";
reg = <0xf800d000 0x20>;
};
timer@f8f00200 {
compatible = "arm,cortex-a9-global-timer";
reg = <0xf8f00200 0x20>;
interrupts = <0x1 0xb 0x301>;
interrupt-parent = <0x4>;
clocks = <0x1 0x4>;
};
timer@f8001000 {
interrupt-parent = <0x4>;
interrupts = <0x0 0xa 0x4 0x0 0xb 0x4 0x0 0xc 0x4>;
compatible = "cdns,ttc";
clocks = <0x1 0x6>;
reg = <0xf8001000 0x1000>;
};
timer@f8002000 {
interrupt-parent = <0x4>;
interrupts = <0x0 0x25 0x4 0x0 0x26 0x4 0x0 0x27 0x4>;
compatible = "cdns,ttc";
clocks = <0x1 0x6>;
reg = <0xf8002000 0x1000>;
};
timer@f8f00600 {
interrupt-parent = <0x4>;
interrupts = <0x1 0xd 0x301>;
compatible = "arm,cortex-a9-twd-timer";
reg = <0xf8f00600 0x20>;
clocks = <0x1 0x4>;
};
watchdog@f8005000 {
clocks = <0x1 0x2d>;
compatible = "cdns,wdt-r1p2";
interrupt-parent = <0x4>;
interrupts = <0x0 0x9 0x1>;
reg = <0xf8005000 0x1000>;
timeout-sec = <0xa>;
};
};
amba_pl {
#address-cells = <0x1>;
#size-cells = <0x1>;
compatible = "simple-bus";
ranges;
i2c@41600000 {
#address-cells = <0x1>;
#size-cells = <0x0>;
clock-names = "s_axi_aclk";
clocks = <0x1 0xf>;
compatible = "xlnx,axi-iic-2.0", "xlnx,xps-iic-2.00.a";
interrupt-names = "iic2intc_irpt";
interrupt-parent = <0x4>;
interrupts = <0x0 0x34 0x4>;
reg = <0x41600000 0x10000>;
};
i2c@41610000 {
#address-cells = <0x1>;
#size-cells = <0x0>;
clock-names = "s_axi_aclk";
clocks = <0x1 0xf>;
compatible = "xlnx,axi-iic-2.0", "xlnx,xps-iic-2.00.a";
interrupt-names = "iic2intc_irpt";
interrupt-parent = <0x4>;
interrupts = <0x0 0x1f 0x4>;
reg = <0x41610000 0x10000>;
i2ctemperature@2 {
compatible = "temperature";
reg = <0x2>;
};
};
i2c@41620000 {
#address-cells = <0x1>;
#size-cells = <0x0>;
clock-names = "s_axi_aclk";
clocks = <0x1 0xf>;
compatible = "xlnx,axi-iic-2.0", "xlnx,xps-iic-2.00.a";
interrupt-names = "iic2intc_irpt";
interrupt-parent = <0x4>;
interrupts = <0x0 0x20 0x4>;
reg = <0x41620000 0x10000>;
i2ctemperature@2 {
compatible = "temperature";
reg = <0x2>;
};
};
i2c@41630000 {
#address-cells = <0x1>;
#size-cells = <0x0>;
clock-names = "s_axi_aclk";
clocks = <0x1 0xf>;
compatible = "xlnx,axi-iic-2.0", "xlnx,xps-iic-2.00.a";
interrupt-names = "iic2intc_irpt";
interrupt-parent = <0x4>;
interrupts = <0x0 0x21 0x4>;
reg = <0x41630000 0x10000>;
i2ctemperature@2 {
compatible = "temperature";
reg = <0x2>;
};
};
i2c@41640000 {
#address-cells = <0x1>;
#size-cells = <0x0>;
clock-names = "s_axi_aclk";
clocks = <0x1 0xf>;
compatible = "xlnx,axi-iic-2.0", "xlnx,xps-iic-2.00.a";
interrupt-names = "iic2intc_irpt";
interrupt-parent = <0x4>;
interrupts = <0x0 0x22 0x4>;
reg = <0x41640000 0x10000>;
i2ctemperature@2 {
compatible = "temperature";
reg = <0x2>;
};
};
i2c@41650000 {
#address-cells = <0x1>;
#size-cells = <0x0>;
clock-names = "s_axi_aclk";
clocks = <0x1 0xf>;
compatible = "xlnx,axi-iic-2.0", "xlnx,xps-iic-2.00.a";
interrupt-names = "iic2intc_irpt";
interrupt-parent = <0x4>;
interrupts = <0x0 0x1d 0x4>;
reg = <0x41650000 0x10000>;
i2ctemperature@2 {
compatible = "temperature";
reg = <0x2>;
};
};
i2c@41660000 {
#address-cells = <0x1>;
#size-cells = <0x0>;
clock-names = "s_axi_aclk";
clocks = <0x1 0xf>;
compatible = "xlnx,axi-iic-2.0", "xlnx,xps-iic-2.00.a";
interrupt-names = "iic2intc_irpt";
interrupt-parent = <0x4>;
interrupts = <0x0 0x1e 0x4>;
reg = <0x41660000 0x10000>;
i2ctemperature@2 {
compatible = "temperature";
reg = <0x2>;
};
};
axi_quad_spi@90000000 {
bits-per-word = <0x8>;
clock-names = "ext_spi_clk", "s_axi_aclk";
clocks = <0x1 0x11 0x1 0xf>;
compatible = "xlnx,axi_qspi-2.00.a";
fifo-size = <0x100>;
interrupt-names = "ip2intc_irpt";
interrupt-parent = <0x4>;
interrupts = <0x0 0x23 0x1>;
num-cs = <0x4>;
reg = <0x90000000 0x10000>;
xlnx,num-ss-bits = <0x4>;
xlnx,spi-mem-addr-bits = <0x18>;
xlnx,spi-memory = <0x2>;
xlnx,type-of-axi4-interface = <0x0>;
xlnx,use-startup = <0x1>;
xlnx,spi-mode = <0x2>;
#address-cells = <0x1>;
#size-cells = <0x0>;
is-dual = <0x0>;
flash@0 {
compatible = "n25q256,spi-nor";
reg = <0x0>;
spi-max-frequency = <0x9ef21b0>;
spi-tx-bus-width = <0x1>;
spi-rx-bus-width = <0x1>;
#address-cells = <0x1>;
#size-cells = <0x1>;
partition@0x0000000 {
label = "spi-flash1";
reg = <0x0 0x2000000>;
};
};
flash@1 {
compatible = "n25q256,spi-nor";
reg = <0x1>;
spi-max-frequency = <0x9ef21b0>;
spi-tx-bus-width = <0x1>;
spi-rx-bus-width = <0x1>;
#address-cells = <0x1>;
#size-cells = <0x1>;
partition@0x0000000 {
label = "spi-flash2";
reg = <0x0 0x2000000>;
};
};
flash@2 {
compatible = "n25q256,spi-nor";
reg = <0x2>;
spi-max-frequency = <0x9ef21b0>;
spi-tx-bus-width = <0x1>;
spi-rx-bus-width = <0x1>;
#address-cells = <0x1>;
#size-cells = <0x1>;
partition@0x0000000 {
label = "spi-flash3";
reg = <0x0 0x2000000>;
};
};
flash@3 {
compatible = "n25q256,spi-nor";
reg = <0x3>;
spi-max-frequency = <0x9ef21b0>;
spi-tx-bus-width = <0x1>;
spi-rx-bus-width = <0x1>;
#address-cells = <0x1>;
#size-cells = <0x1>;
partition@0x0000000 {
label = "spi-flash4";
reg = <0x0 0x2000000>;
};
};
};
axi_quad_spi@80000000 {
bits-per-word = <0x8>;
clock-names = "ext_spi_clk", "s_axi_aclk";
clocks = <0x1 0x11 0x1 0xf>;
compatible = "xlnx,axi_qspi-2.00.a";
fifo-size = <0x100>;
interrupt-names = "ip2intc_irpt";
interrupt-parent = <0x4>;
interrupts = <0x0 0x24 0x1>;
num-cs = <0x4>;
reg = <0x80000000 0x10000>;
xlnx,num-ss-bits = <0x4>;
xlnx,spi-mem-addr-bits = <0x18>;
xlnx,spi-memory = <0x2>;
xlnx,type-of-axi4-interface = <0x0>;
xlnx,use-startup = <0x1>;
xlnx,spi-mode = <0x2>;
#address-cells = <0x1>;
#size-cells = <0x0>;
is-dual = <0x0>;
flash@0 {
compatible = "n25q256,spi-nor";
reg = <0x0>;
spi-max-frequency = <0x9ef21b0>;
spi-tx-bus-width = <0x1>;
spi-rx-bus-width = <0x1>;
#address-cells = <0x1>;
#size-cells = <0x1>;
partition@0x0000000 {
label = "spi-flash5";
reg = <0x0 0x2000000>;
};
};
flash@1 {
compatible = "n25q256,spi-nor";
reg = <0x1>;
spi-max-frequency = <0x9ef21b0>;
spi-tx-bus-width = <0x1>;
spi-rx-bus-width = <0x1>;
#address-cells = <0x1>;
#size-cells = <0x1>;
partition@0x0000000 {
label = "spi-flash6";
reg = <0x0 0x2000000>;
};
};
flash@2 {
compatible = "n25q256,spi-nor";
reg = <0x2>;
spi-max-frequency = <0x9ef21b0>;
spi-tx-bus-width = <0x1>;
spi-rx-bus-width = <0x1>;
#address-cells = <0x1>;
#size-cells = <0x1>;
partition@0x0000000 {
label = "spi-flash7";
reg = <0x0 0x2000000>;
};
};
flash@3 {
compatible = "n25q256,spi-nor";
reg = <0x3>;
spi-max-frequency = <0x9ef21b0>;
spi-tx-bus-width = <0x1>;
spi-rx-bus-width = <0x1>;
#address-cells = <0x1>;
#size-cells = <0x1>;
partition@0x0000000 {
label = "spi-flash8";
reg = <0x0 0x2000000>;
};
};
};
};
chosen {
bootargs = "earlycon vmalloc=400M";
stdout-path = "serial0:115200n8";
};
aliases {
ethernet0 = "/amba/ethernet@e000b000";
ethernet1 = "/amba/ethernet@e000c000";
serial0 = "/amba/serial@e0000000";
spi0 = "/amba/spi@e000d000";
spi1 = "/amba_pl/axi_quad_spi@90000000";
spi2 = "/amba_pl/axi_quad_spi@80000000";
flash0 = "/amba_pl/axi_quad_spi@90000000/flash@0";
flash1 = "/amba_pl/axi_quad_spi@90000000/flash@1";
flash2 = "/amba_pl/axi_quad_spi@90000000/flash@2";
flash3 = "/amba_pl/axi_quad_spi@90000000/flash@3";
flash4 = "/amba_pl/axi_quad_spi@80000000/flash@0";
flash5 = "/amba_pl/axi_quad_spi@80000000/flash@1";
flash6 = "/amba_pl/axi_quad_spi@80000000/flash@2";
flash7 = "/amba_pl/axi_quad_spi@80000000/flash@3";
};
memory {
device_type = "memory";
reg = <0x0 0x40000000>;
};
};
4.内核配置
内核中需要增加从设备驱动，根据厂家提供的i2c读写时序仿照之前的1848驱动来做，注意由于i2c地址全都是0x50（手册上读写地址分别为0xA0,0xA1，右移一位读写位后就是0x50），所以驱动里面地址可以写成固定值，如下图：
完整代码如下：
/*
* temperature bus driver
*
* Copyright (C) 2014 CGT Corp.
*
* 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; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#define DEBUG
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
#include <linux/delay.h>
#include <linux/serial_core.h>
/* Each client has this additional data */
#define USER_EEPROM_SIZE 0xFFFF48
#define USER_XFER_MAX_COUNT 0x8
/* Addresses to scan */
static const unsigned short temperature_i2c[] = { 0x3, I2C_CLIENT_END };
static unsigned read_timeout = 25;
module_param(read_timeout, uint, 0);
MODULE_PARM_DESC(read_timeout, "Time (in ms) to try reads (default 25)");
static unsigned write_timeout = 25;
module_param(write_timeout, uint, 0);
MODULE_PARM_DESC(write_timeout, "Time (in ms) to try writes (default 25)");
struct temperature_data {
struct mutex lock;
u8 *data;
};
static ssize_t temperature_read_data( struct i2c_client *client,
char *buf, unsigned offset, size_t count)
{
struct i2c_msg msg[2];
u8 msgbuf[4];
unsigned long timeout, transfer_time;
int status;
memset(msg, 0, sizeof(msg));
msgbuf[0] = (u8)(offset & 0xff);
msg[0].addr = 0x50;//client->addr;
msg[0].buf = msgbuf;
msg[0].len = 1;
msg[1].addr = 0x50;//client->addr;
msg[1].flags = I2C_M_RD;
msg[1].buf = buf;
msg[1].len = count;
/*
* Reads fail if the previous write didn't complete yet. We may
* loop a few times until this one succeeds, waiting at least
* long enough for one entire page write to work.
*/
timeout = jiffies + msecs_to_jiffies(read_timeout);
do {
transfer_time = jiffies;
status = i2c_transfer(client->adapter, msg, 2);
if (status == 2)
status = count;
dev_dbg(&client->dev, "read %ld@0x%lx --> %d (%ld)\n",
count, (unsigned long)offset, status, jiffies);
if (status == count)
return count;
/* REVISIT: at HZ=100, this is sloooow */
msleep(1);
} while (time_before(transfer_time, timeout));
return -ETIMEDOUT;
}
static ssize_t temperature_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t offset, size_t count)
{
struct i2c_client *client = kobj_to_i2c_client(kobj);
struct temperature_data *data = i2c_get_clientdata(client);
ssize_t retval = 0;
if (offset > USER_EEPROM_SIZE)
return 0;
if (offset + count > USER_EEPROM_SIZE)
count = USER_EEPROM_SIZE - offset;
mutex_lock(&data->lock);
dev_dbg(&client->dev, "cps226 start read %ld@0x%lx ..\n", count, (unsigned long)offset);
while (count > 0) {
ssize_t status = count>USER_XFER_MAX_COUNT?USER_XFER_MAX_COUNT:count;
status = temperature_read_data(client, buf, offset, status);
if (status <= 0) {
if (retval == 0)
retval = status;
break;
}
buf += status;
offset += status;
count -= status;
retval += status;
}
dev_dbg(&client->dev, "cps226 end read %ld@0x%lx !\n", retval, (unsigned long)offset);
mutex_unlock(&data->lock);
return retval;
}
static ssize_t temperature_write_config(
struct i2c_client *client,
struct temperature_data *data,
char *buf, unsigned offset, size_t count)
{
struct i2c_msg msg[1];
u8 *msgbuf;
unsigned long timeout, transfer_time;
int status;
memset(msg, 0, sizeof(msg));
msgbuf = data->data;
// msgbuf[0] = (u8)((offset >> 18) & 0x3f);
// msgbuf[1] = (u8)((offset >> 10) & 0xff);
// msgbuf[2] = (u8)((offset >> 2) & 0xff);
msgbuf[0] = (u8)(offset& 0xff);
memcpy(msgbuf+1, buf, count);
msg[0].addr = 0x50;//client->addr;
msg[0].buf = msgbuf;
msg[0].len = 1 + count;
/*
* Reads fail if the previous write didn't complete yet. We may
* loop a few times until this one succeeds, waiting at least
* long enough for one entire page write to work.
*/
timeout = jiffies + msecs_to_jiffies(write_timeout);
do {
transfer_time = jiffies;
status = i2c_transfer(client->adapter, msg, 1);
if (status == 1)
status = count;
dev_dbg(&client->dev, "write %ld@0x%lx --> %d (%ld)\n",
count, (unsigned long)offset, status, jiffies);
if (status == count)
return count;
/* REVISIT: at HZ=100, this is sloooow */
msleep(1);
} while (time_before(transfer_time, timeout));
return -ETIMEDOUT;
}
static ssize_t temperature_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t offset, size_t count)
{
struct i2c_client *client = kobj_to_i2c_client(kobj);
struct temperature_data *data = i2c_get_clientdata(client);
ssize_t retval = 0;
if (offset > USER_EEPROM_SIZE)
return 0;
if (offset + count > USER_EEPROM_SIZE)
count = USER_EEPROM_SIZE - offset;
mutex_lock(&data->lock);
dev_dbg(&client->dev, "temperature start write %ld@0x%lx ..\n", count, (unsigned long)offset);
while (count > 0) {
ssize_t status = count>USER_XFER_MAX_COUNT?USER_XFER_MAX_COUNT:count;
status = temperature_write_config(client, data, buf, offset, status);
if (status <= 0) {
if (retval == 0)
retval = status;
break;
}
buf += status;
offset += status;
count -= status;
retval += status;
}
dev_dbg(&client->dev, "temperature end write %ld@0x%lx !\n", retval, (unsigned long)offset);
mutex_unlock(&data->lock);
return retval;
}
static struct bin_attribute user_temperature_attr = {
.attr = {
.name = "temperature",
.mode = (S_IRUSR | S_IWUSR),
},
.size = USER_EEPROM_SIZE,
.read = temperature_read,
.write = temperature_write,
};
/* Return 0 if detection is successful, -ENODEV otherwise */
static int temperature_detect(struct i2c_client *client, struct i2c_board_info *info)
{
struct i2c_adapter *adapter = client->adapter;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
dev_dbg(&client->dev, "temperature detect error for BYTE access !\n");
return -ENODEV;
}
strlcpy(info->type, "temperature", I2C_NAME_SIZE);
return 0;
}
static int temperature_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct i2c_adapter *adapter = client->adapter;
struct temperature_data *data;
int err ;
dev_notice(&client->dev, "temperature driver\n" );
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
dev_err(&client->dev, "temperature data driver: BYTE DATA not supported! \n" );
return -ENODEV;
}
if (!(data = kzalloc(sizeof(struct temperature_data), GFP_KERNEL))) {
dev_err(&client->dev, "temperature data driver: Memory alloc error ! \n" );
return -ENOMEM;
}
/* alloc buffer */
data->data = devm_kzalloc(&client->dev, USER_XFER_MAX_COUNT + 8, GFP_KERNEL);
if (!data->data) {
dev_err(&client->dev, "temperature data driver: Memory alloc error ! \n" );
err = -ENOMEM;
goto exit_kfree;
}
/* Init real i2c_client */
i2c_set_clientdata(client, data);
mutex_init(&data->lock);
err = sysfs_create_bin_file(&client->dev.kobj, &user_temperature_attr);
if (err) {
dev_err(&client->dev, "temperature data driver: sysfs create error ! \n" );
goto exit_kfree;
}
return 0;
exit_kfree:
if(data->data)
kfree(data->data);
kfree(data);
return err;
}
static int temperature_remove(struct i2c_client *client)
{
struct temperature_data *data = i2c_get_clientdata(client);
sysfs_remove_bin_file(&client->dev.kobj, &user_temperature_attr);
if(data->data)
kfree(data->data);
kfree(data);
return 0;
}
static const struct i2c_device_id temperature_id[] = {
{ "temperature", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, temperature_id);
static struct i2c_driver temperature_driver = {
.driver = {
.name = "temperature",
},
.probe = temperature_probe,
.remove = temperature_remove,
.id_table = temperature_id,
.class = I2C_CLASS_SPD,
.detect = temperature_detect,
.address_list = temperature_i2c,
};
module_i2c_driver(temperature_driver);
MODULE_AUTHOR("RobinLee");
MODULE_DESCRIPTION("temperature driver");
MODULE_LICENSE("GPL");
然后将驱动编进内核
最后修改config配置文件，增加CONFIG_I2C_XILINX
5.应用测试
应用中只需要打开设备，然后读写寄存器即可，代码如下：
#define I2C_0 "/sys/class/i2c-dev/i2c-3/device/3-0002/temperature" //8518,电压是0x1A,0X1B,温度是0x1E,0X1F
#define I2C_1 "/sys/class/i2c-dev/i2c-4/device/4-0002/temperature" //8514,电压是0x16,0X17,温度是0x14,0X15
#define I2C_2 "/sys/class/i2c-dev/i2c-5/device/5-0002/temperature" //8514,电压是0x16,0X17,温度是0x14,0X15
#define I2C_3 "/sys/class/i2c-dev/i2c-6/device/6-0002/temperature" //8514,电压是0x16,0X17,温度是0x14,0X15
#define I2C_4 "/sys/class/i2c-dev/i2c-7/device/7-0002/temperature" //8513,电压是0x16,0X17，温度是0x12,0X13
#define I2C_5 "/sys/class/i2c-dev/i2c-8/device/8-0002/temperature" //8513,电压是0x16,0X17，温度是0x12,0X13
static int fp_i2c_0, fp_i2c_1, fp_i2c_2, fp_i2c_3, fp_i2c_4, fp_i2c_5;
void init_i2c_file_opt(void)
{
fp_i2c_0 = open(I2C_0, O_RDWR);
printf("input fd:%d !\n", fp_i2c_0);
if (fp_i2c_0 == NULL)
printf("open ic-0 failed..\n");
fp_i2c_1 = open(I2C_1, O_RDWR);
printf("input fd:%d !\n", fp_i2c_1);
if (fp_i2c_1 == NULL)
printf("open ic-1 failed..\n");
fp_i2c_2 = open(I2C_2, O_RDWR);
printf("input fd:%d !\n", fp_i2c_2);
if (fp_i2c_2 == NULL)
printf("open ic-2 failed..\n");
fp_i2c_3 = open(I2C_3, O_RDWR);
printf("input fd:%d !\n", fp_i2c_3);
if (fp_i2c_3 == NULL)
printf("open ic-3 failed..\n");
fp_i2c_4 = open(I2C_4, O_RDWR);
printf("input fd:%d !\n", fp_i2c_4);
if (fp_i2c_4 == NULL)
printf("open ic-4 failed..\n");
fp_i2c_5 = open(I2C_5, O_RDWR);
printf("input fd:%d !\n", fp_i2c_5);
if (fp_i2c_5 == NULL)
printf("open ic-5 failed..\n");
}
int read_temperatue(unsigned int num, unsigned int offset)
{
int fd = -1;
char value = -1;
if (num == 0)
{
fd = fp_i2c_0;
}
else if (num == 1)
{
fd = fp_i2c_1;
}
else if (num == 2)
{
fd = fp_i2c_2;
}
else if (num == 3)
{
fd = fp_i2c_3;
}
else if (num == 4)
{
fd = fp_i2c_4;
}
else if (num == 5)
{
fd = fp_i2c_5;
}
else
{
printf("input error::Invalid param !\n");
return 0;
}
if (fd < 0)
{
printf("Invalid device handle !\n");
return value;
}
if (lseek(fd, offset, SEEK_SET) == (off_t) - 1)
{
printf("failed for seek to offset 0x%x !\n", offset);
return value;
}
if (read(fd, &value, sizeof(value)) != sizeof(value))
{
printf("failed for read from offset 0x%x !\n", offset);
return value;
}
return value;
}
void i2c_temp(void)
{
unsigned int addr = 0;
int value = 0;
int value2 = 0;
float temp;
int i;
for(i=0;i<6;i++)
{
//volt info
if (i == 0) //除了8518，其他的电压计算公式和地址都一样
{
value = read_temperatue(i,0x1A);
value2 = read_temperatue(i,0x1B);
printf("No. %d----value:%d ,value2:%d, vol:%d mV\n",i,value,value2, value*256+value2);
}
else
{
value = read_temperatue(i,0x16);
value2 = read_temperatue(i,0x17);
printf("No. %d----value:%d ,value2:%d, vol:%f mV\n",i,value,value2, (float)(((float)value*256.0+(float)value2)*0.1));
}
sleep(1);
//temperature info
if ((i == 1) || (i == 2) || (i == 3)) //这三个是8514，两个温度处理
{
value = read_temperatue(i,0x14);
value2 = read_temperatue(i,0x15);
if(value < 128)
{
temp = value + (float)value2/256;
}
else
{
temp = value -256 + (float)value2/256;
}
printf("No. %d----value:%d ,value2:%d, temp:%f cent\n",i,value,value2, temp);
}
else if (i == 0) //8518
{
value = read_temperatue(i,0x1E);
value2 = read_temperatue(i,0x1F);
if(value < 128)
{
temp = value + (float)value2/256;
}
else
{
temp = value -256 + (float)value2/256;
}
printf("No. %d----value:%d ,value2:%d, temp:%f cent\n",i,value,value2, temp);
}
else //8513
{
value = read_temperatue(i,0x12);
value2 = read_temperatue(i,0x13);
if(value < 128)
{
temp = value + (float)value2/256;
}
else
{
temp = value -256 + (float)value2/256;
}
printf("No. %d----value:%d ,value2:%d, temp:%f cent\n",i,value,value2, temp);
}
sleep(1);
printf("\n\r");
}
}
测试结果可以读写
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