SiI9022A是一款HDMI传输芯片，可以将“音视频接口”转换为HDMI或者DVI格式，是一个视频转换芯片。本实验基于linux的驱动程序设计。

SiI9022A支持输入视频格式有：xvYCC、BTA-T1004、ITU-R.656，内置DE发生器，支持SYNC格式(RGB 格式)。输出格式支持：HDMI、HDCP和DVI、最高支持1080P视频输出、支持HDMI A、HDMI C和Micro-D连接器。SiI9022A使用I2C接口进行配置。由于STM32MP157没有HDMI外设，只有RGB屏幕接口，因此，我们可以通过RGB转HDMI的芯片SiI9022A来实现HDMI连接。

1、了解SiI9022A的相关寄存器

#define SII902X_TPI_PIXEL_REPETITION  0x8

/*TPI输入总线和像素重复数据寄存器地址为0x08*/

#define SII902X_TPI_AVI_PIXEL_REP_BUS_24BIT     BIT(5)

/*输入总线选择：bit5=0半像素宽;bit5=1全像素宽*/

#define SII902X_TPI_AVI_PIXEL_REP_RISING_EDGE   BIT(4)

/*边沿选择：bit4=0下降沿;bit4=1上升沿*/

#define SII902X_TPI_AVI_PIXEL_REP_4X 3

/*像素重复因子：PR[3:0]=0011b,每个像素发送4次*/

#define SII902X_TPI_AVI_PIXEL_REP_2X 1

/*像素重复因子：PR[3:0]=0001b,每个像素发送2次*/

#define SII902X_TPI_AVI_PIXEL_REP_NONE 0

/*像素重复因子：PR[3:0]=0000b,每个像素发送1次，不用重复发送*/

#define SII902X_TPI_CLK_RATIO_HALF (0 << 6) /*bit7:6=00b,TCLK选择0.5倍的速度*/

#define SII902X_TPI_CLK_RATIO_1X (1 << 6) /*bit7:6=01b,TCLK选择1倍的速度*/

#define SII902X_TPI_CLK_RATIO_2X (2 << 6) /*bit7:6=10b,TCLK选择2倍的速度*/

#define SII902X_TPI_CLK_RATIO_4X (3 << 6) /*bit7:6=11b,TCLK选择4倍的速度*/

#define SII902X_TPI_AVI_IN_FORMAT 0x9

/*TPI AVI输入和输出格式数据配置寄存器地址为0x09*/

#define SII902X_TPI_AVI_INPUT_BITMODE_12BIT BIT(7)

#define SII902X_TPI_AVI_INPUT_DITHER BIT(6)

/*bit7:6=00b,输入颜色深度8位*/

/*bit7:6=01b,没有定义"输入颜色深度"*/

/*颜色抖动则是尝试用较低的颜色位深度来获得更为丰富的视觉效果,

比如用1位的位深度来尽可能得到8位的视觉效果*/

/*bit7:6=10b,输入颜色深度10/12位,在4:2:2模式中，无"颜色抖动"*/

/*bit7:6=11b,输入颜色深度10/12位,在4:2:2模式中，"颜色抖动"为8位的视觉效果*/

#define SII902X_TPI_AVI_INPUT_RANGE_LIMITED (2 << 2)

/*bit3:2=10b,关闭视频范围扩展*/

#define SII902X_TPI_AVI_INPUT_RANGE_FULL (1 << 2) /*bit3:2=01b,打开视频范围扩展*/

#define SII902X_TPI_AVI_INPUT_RANGE_AUTO (0 << 2)

/*bit3:2=00b,自动选择"视频范围扩展"*/

#define SII902X_TPI_AVI_INPUT_COLORSPACE_BLACK (3 << 0)

/*bit1:0=11b,输入色彩为Black模式*/

#define SII902X_TPI_AVI_INPUT_COLORSPACE_YUV422 (2 << 0)

/*bit1:0=10b,输入色彩为YCbCr 4:2:2模式*/

#define SII902X_TPI_AVI_INPUT_COLORSPACE_YUV444 (1 << 0)

/*bit1:0=01b,输入色彩为YCbCr 4:4:4模式*/

#define SII902X_TPI_AVI_INPUT_COLORSPACE_RGB (0 << 0)

/*bit1:0=01b,输入色彩为RGB模式*/

#define SII902X_TPI_AVI_INFOFRAME 0x0c

/*"AVI信息帧寄存器"起始地址为0x0C*/

/*用来存放"AVI信息帧校验和"*/

#define SII902X_SYS_CTRL_DATA 0x1a /*系统控制寄存器地址为0x1A*/

#define SII902X_SYS_CTRL_PWR_DWN BIT(4)

/*bit4=0b,TDMS输出控制激活;bit4=1b,TDMS输出控制关闭*/

#define SII902X_SYS_CTRL_AV_MUTE BIT(3)

/*bit3=0b,普通的音视频，指同时包含音频和视频内容的媒体形式;*/

/*bit3=1b,配置为音频和视频接收器*/

#define SII902X_SYS_CTRL_DDC_BUS_REQ BIT(2)

/*bit2=0b,主机无需请求使用DDC总线*/

/*bit2=1b,主机请求使用DDC总线*/

#define SII902X_SYS_CTRL_DDC_BUS_GRTD BIT(1)

/*bit1=0b,DDC总线不可用*/

/*bit1=1b,主机可以写DDC总线*/

#define SII902X_SYS_CTRL_OUTPUT_MODE BIT(0)

/*bit0=0b,输出模式选择为DVI,bit0=1b,输出模式选择为HDMI*/

#define SII902X_SYS_CTRL_OUTPUT_HDMI 1 /*bit0=1b,输出模式选择为HDMI*/

#define SII902X_SYS_CTRL_OUTPUT_DVI 0 /*bit0=0b,输出模式选择为DVI*/

#define SII902X_REG_CHIPID(n) (0x1b + (n))

/*地址范围0x1B～0x1D，保存的是TPI芯片的ID和版本*/

#define SII902X_PWR_STATE_CTRL 0x1e

/*TPI设备电源状态控制数据寄存器地址为0x1E*/

#define SII902X_AVI_POWER_STATE_MSK GENMASK(1, 0)  /*结果为0x03*/

#define SII902X_AVI_POWER_STATE_D(l) ((l) & SII902X_AVI_POWER_STATE_MSK)

/*执行SII902X_AVI_POWER_STATE_D(0);//结果为0x00*/

/*Power_state[1:0] = 00b，配置"全功率操作模式"*/

#define BITS_PER_LONG 32

#define GENMASK(h, l)  ( ( (~(u32)(0)) - ((u32)(1) << (l) ) + 1 ) & ( ~(u32)(0) >> (BITS_PER_LONG - 1 - (h)) ) )

#define SII902X_AVI_POWER_STATE_MSK GENMASK(1, 0)  /*结果为0x03*/

#define SII902X_AVI_POWER_STATE_D(l) ((l) & SII902X_AVI_POWER_STATE_MSK)

d=SII902X_AVI_POWER_STATE_D(0);/*结果为0x00*/

#define SII902X_TPI_I2S_ENABLE_MAPPING_REG 0x1f

/*Audio配置寄存器起始地址为0x1F*/

#define SII902X_TPI_I2S_CONFIG_FIFO0 (0 << 0) /*bit1:0=00b,FIFO使用通道0*/

#define SII902X_TPI_I2S_CONFIG_FIFO1 (1 << 0) /*bit1:0=01b,FIFO使用通道1*/

#define SII902X_TPI_I2S_CONFIG_FIFO2 (2 << 0) /*bit1:0=10b,FIFO使用通道2*/

#define SII902X_TPI_I2S_CONFIG_FIFO3 (3 << 0) /*bit1:0=11b,FIFO使用通道3*/

#define SII902X_TPI_I2S_LEFT_RIGHT_SWAP (1 << 2)

/*bit2=0b,I2S左右通道不用交换;*/

/*bit2=1b,I2S左右通道交换*/

#define SII902X_TPI_I2S_AUTO_DOWNSAMPLE (1 << 3)

/*bit3=0b,FIFO使用通道0不用自动下采样到"基本音频模式"*/

/*bit3=1b,FIFO使用通道0会自动下采样到"基本音频模式"*/

#define SII902X_TPI_I2S_SELECT_SD0 (0 << 4) /*bit5:4=00b,选择SD0引脚*/

#define SII902X_TPI_I2S_SELECT_SD1 (1 << 4) /*bit5:4=01b,选择SD1引脚*/

#define SII902X_TPI_I2S_SELECT_SD2 (2 << 4) /*bit5:4=10b,选择SD2引脚*/

#define SII902X_TPI_I2S_SELECT_SD3 (3 << 4) /*bit5:4=11b,选择SD3引脚*/

#define SII902X_TPI_I2S_FIFO_ENABLE (1 << 7)

/*bit7=0b,不使能"SD引脚"选择;*/

/*bit7=1b,使能"SD引脚"选择;*/

#define SII902X_TPI_I2S_INPUT_CONFIG_REG 0x20 /*I2S输入配置寄存器的地址为0x20*/

#define SII902X_TPI_I2S_FIRST_BIT_SHIFT_YES (0 << 0)

/*bit0=0b,将WS转换为SD，第1位要移位*/

#define SII902X_TPI_I2S_FIRST_BIT_SHIFT_NO (1 << 0)

/*bit0=1b,将WS转换为SD，第1位不用移位*/

#define SII902X_TPI_I2S_SD_DIRECTION_MSB_FIRST (0 << 1)

/*bit1=0b,字节移位第1位为最高位*/

#define SII902X_TPI_I2S_SD_DIRECTION_LSB_FIRST (1 << 1)

/*bit1=1b,字节移位第1位为最低位*/

#define SII902X_TPI_I2S_SD_JUSTIFY_LEFT (0 << 2) /*bit2=0b,数据左对齐*/

#define SII902X_TPI_I2S_SD_JUSTIFY_RIGHT (1 << 2) /*bit2=1b,数据右对齐*/

#define SII902X_TPI_I2S_WS_POLARITY_LOW (0 << 3) /*bit3=0b,WS极性为LOW*/

#define SII902X_TPI_I2S_WS_POLARITY_HIGH (1 << 3) /*bit3=1b,WS极性为HIGH*/

#define SII902X_TPI_I2S_MCLK_MULTIPLIER_128 (0 << 4) /*bit6:4=000b,MCLK乘数为128*/

#define SII902X_TPI_I2S_MCLK_MULTIPLIER_256 (1 << 4) /*bit6:4=001b,MCLK乘数为256*/

#define SII902X_TPI_I2S_MCLK_MULTIPLIER_384 (2 << 4) /*bit6:4=010b,MCLK乘数为384*/

#define SII902X_TPI_I2S_MCLK_MULTIPLIER_512 (3 << 4) /*bit6:4=011b,MCLK乘数为512*/

#define SII902X_TPI_I2S_MCLK_MULTIPLIER_768 (4 << 4) /*bit6:4=100b,MCLK乘数为768*/

#define SII902X_TPI_I2S_MCLK_MULTIPLIER_1024 (5 << 4)

/*bit6:4=101b,MCLK乘数为1024*/

#define SII902X_TPI_I2S_MCLK_MULTIPLIER_1152 (6 << 4)

/*bit6:4=110b,MCLK乘数为1152*/

#define SII902X_TPI_I2S_MCLK_MULTIPLIER_192 (7 << 4) /*bit6:4=111b,MCLK乘数为192*/

#define SII902X_TPI_I2S_SCK_EDGE_FALLING  (0 << 7) /*bit7=0b,SCK采样边沿为下降沿*/

#define SII902X_TPI_I2S_SCK_EDGE_RISING    (1 << 7) /*bit7=1b,SCK采样边沿为上升沿*/

#define SII902X_TPI_I2S_STRM_HDR_BASE 0x21 /*I2S通道状态寄存器起始地址为0x21*/

#define SII902X_TPI_I2S_STRM_HDR_SIZE 5   /*I2S通道状态寄存器数量为5*/

#define SII902X_TPI_AUDIO_CONFIG_BYTE2_REG 0x26

/*TPI Audio配置寄存器地址为0x26*/

#define SII902X_TPI_AUDIO_CODING_STREAM_HEADER (0 << 0)

/*CT[3:0]=0000b,音频配置类型参考流头*/

#define SII902X_TPI_AUDIO_CODING_PCM (1 << 0) /*CT[3:0]=0001b,音频配置类型为PCM*/

#define SII902X_TPI_AUDIO_CODING_AC3 (2 << 0) /*CT[3:0]=0010b,音频配置类型为AC-3*/

#define SII902X_TPI_AUDIO_CODING_MPEG1 (3 << 0)

/*CT[3:0]=0011b,音频配置类型为MPEG1*/

#define SII902X_TPI_AUDIO_CODING_MP3 (4 << 0) /*CT[3:0]=0100b,音频配置类型为MP3*/

#define SII902X_TPI_AUDIO_CODING_MPEG2 (5 << 0)

/*CT[3:0]=0101b,音频配置类型为MPED2*/

#define SII902X_TPI_AUDIO_CODING_AAC (6 << 0) /*CT[3:0]=0110b,音频配置类型为AAC*/

#define SII902X_TPI_AUDIO_CODING_DTS (7 << 0) /*CT[3:0]=0111b,音频配置类型为DTS*/

#define SII902X_TPI_AUDIO_CODING_ATRAC (8 << 0) /*CT[3:0]=1000b,音频配置类型为ATRAC*/

#define SII902X_TPI_AUDIO_MUTE_DISABLE (0 << 4) /*Mute=0b表示普通音*/

#define SII902X_TPI_AUDIO_MUTE_ENABLE  (1 << 4) /*Mute=1b表示使用弱音器*/

#define SII902X_TPI_AUDIO_LAYOUT_2_CHANNELS (0 << 5)

/*Layout=0b,表示音频包头布局指示器0*/

#define SII902X_TPI_AUDIO_LAYOUT_8_CHANNELS (1 << 5)

/*Layout=1b,表示音频包头布局指示器1*/

#define SII902X_TPI_AUDIO_INTERFACE_DISABLE (0 << 6) /*00b，表示不使用Audio接口*/

#define SII902X_TPI_AUDIO_INTERFACE_SPDIF (1 << 6) /*01b，表示Audio接口使用S/PDIF*/

#define SII902X_TPI_AUDIO_INTERFACE_I2S (2 << 6) /*10b，表示Audio接口使用I2S*/

#define SII902X_TPI_AUDIO_CONFIG_BYTE3_REG 0x27

/*TPI Audio配置寄存器地址为0x27*/

#define SII902X_TPI_AUDIO_FREQ_STREAM (0 << 3) /*SF[2:0]=000b,Audio采样频率参考流头;*/

#define SII902X_TPI_AUDIO_FREQ_32KHZ (1 << 3) /*SF[2:0]=001b,Audio采样频率为32KHz;*/

#define SII902X_TPI_AUDIO_FREQ_44KHZ (2 << 3)

/*SF[2:0]=010b,Audio采样频率为44.1KHz;*/

#define SII902X_TPI_AUDIO_FREQ_48KHZ (3 << 3)

/*SF[2:0]=011b,Audio采样频率为48KHz;*/

#define SII902X_TPI_AUDIO_FREQ_88KHZ (4 << 3)

/*SF[2:0]=100b,Audio采样频率为88.2KHz;*/

#define SII902X_TPI_AUDIO_FREQ_96KHZ (5 << 3) /*SF[2:0]=101b,Audio采样频率为96KHz;*/

#define SII902X_TPI_AUDIO_FREQ_176KHZ (6 << 3)

/*SF[2:0]=110b,Audio采样频率为176.4KHz;*/

#define SII902X_TPI_AUDIO_FREQ_192KHZ (7 << 3)

/*SF[2:0]=111b,Audio采样频率为192KHz;*/

#define SII902X_TPI_AUDIO_SAMPLE_SIZE_STREAM (0 << 6)

/*SS[1:0]=00,Audio采样位数参考流头;*/

#define SII902X_TPI_AUDIO_SAMPLE_SIZE_16 (1 << 6) /*SS[1:0]=01,Audio采样位数为16位;*/

#define SII902X_TPI_AUDIO_SAMPLE_SIZE_20 (2 << 6) /*SS[1:0]=10,Audio采样位数为20位;*/

#define SII902X_TPI_AUDIO_SAMPLE_SIZE_24 (3 << 6) /*SS[1:0]=1q,Audio采样位数为24位;*/

#define SII902X_TPI_AUDIO_CONFIG_BYTE4_REG 0x28

/*Audio配置寄存器结束地址为0x28，保留不用*/

#define SII902X_INT_ENABLE 0x3c  /*"中断使能寄存器"起始地址为0x3C*/

#define SII902X_HOTPLUG_EVENT BIT(0) /*"中断使能寄存器"bit0=1,即使能sii902x输出中断*/

#define SII902X_INT_STATUS 0x3d  /*"中断状态寄存器"结束地址为0x3D*/

#define SII902X_PLUGGED_STATUS BIT(2) /*"中断状态寄存器"bit2=1,表示产生中断*/

#define SII902X_REG_TPI_RQB 0xc7

/*复位和初始化寄存器地址为0xC7*/

/*复位芯片，接着向地址0xC7的寄存器写入0x00，使能TPI模式*/

/*间接内部寄存器访问,Indirect internal register access*/

#define SII902X_IND_SET_PAGE 0xbc /*页寄存器地址为0xBC*/

#define SII902X_IND_OFFSET 0xbd /*变址寄存器地址为0xBD*/

#define SII902X_IND_VALUE 0xbe

/*由页寄存器和变址寄存器选中的寄存器，即为当前寄存器(其固定地址为0xBE)*/

#define SII902X_TPI_MISC_INFOFRAME_BASE 0xbf

/*"TPI杂项信息帧数据寄存器"起始地址为0xBF*/

#define SII902X_TPI_MISC_INFOFRAME_END 0xde

/*"TPI杂项信息帧数据寄存器"结束地址为0xDE*/

#define SII902X_TPI_MISC_INFOFRAME_SIZE \

(SII902X_TPI_MISC_INFOFRAME_END - SII902X_TPI_MISC_INFOFRAME_BASE)

/*"其它信息帧寄存器"的数量，感觉这里少了1个？？？*/

2、SiI9022A的原理图

STM32MP157使用I2C2接口对SiI9022A进行配置，这里用到了PH4(I2C2_SCL)和PH5(I2C2_SDA)这两个引脚。另外还有一个HDMI_INT中断引脚连接到PH6，一个复位HDMI_RESET引脚连接到PA3。该实验主要是实现HDMI的显示功能，因此，不用去管音频接口。

3、修改设备树

3.1、打开设备树头文件“stm32mp15-pinctrl.dtsi”，找到“i2c2_pins_a”，内容如下：

i2c2_pins_a: i2c2-0 { /*在默认状态下使用*/

pins {

pinmux = <STM32_PINMUX('H', 4, AF4)>, /* I2C2_SCL */

 <STM32_PINMUX('H', 5, AF4)>; /* I2C2_SDA */

bias-disable;/*禁止使用内部偏置电压*/

drive-open-drain;/*开漏输出*/

slew-rate = <0>;/*引脚的速度，可设置:0~3，0最慢，3 最高*/

};

};

i2c2_pins_sleep_a: i2c2-1 { /*在睡眠状态下使用*/

pins {

pinmux = <STM32_PINMUX('H', 4, ANALOG)>, /* I2C2_SCL */

 <STM32_PINMUX('H', 5, ANALOG)>; /* I2C2_SDA */

};

};

3.2、SiI9022A需要一个 1.2V 电压，打开“stm32mp157d-atk.dts”,添加内容如下(注意：是在根节点“/”下添加)：

v1v2_hdmi:regulator-v1v2-hdmi {

compatible ="requlator-fixed";

regulator-name ="v1v2_hdmi";

regulator-min-microvolt=<1200000>;

regulator-max-microvolt=<1200000>;

regulator-always-on;

regulator-boot-on;

};

3.3、打开“stm32mp157d-atk.dts”,添加内容如下(注意：不是在根节点“/”下添加)：

&i2c2 {

pinctrl-names ="default", "sleep";

pinctrl-0=<&i2c2_pins_a>;/*pinctrl-0为default模式*/

pinctrl-1 =<&i2c2_pins_sleep_a>;/*pinctrl-1为sleep模式*/

/*设置了两个pinmux模式：pinctrl-0为default模式，pinctrl-1为sleep模式，

系统默认使用default模式。*/

status = "okay";

hdmi: hdmi-transmitter@39 {

/*向i2c2添加hdmi-transmitter子节点,“@”后面的“39”就是SiI9022A的I2C器件地址*/

compatible ="sil,sii9022";/*compatible属性值为"sil,sii9022"*/

reg = <0x39>;/*reg属性是设置SiI9022A的器件地址0x39*/

iovcc-supply = <&v3v3>;

cvcc12-supply = <&v1v2_hdmi>;

reset-gpios = <&gpioa 3 GPIO_ACTIVE_LOW>;/*设置复位引脚为PA3,低电压有效*/

interrupt-parent = <&gpioh>;/*指定父中断器为&gpioh*/

/*通过interrupt-parent属性指定SiI9022A的INT引脚的中断父节点为gpioh*/

interrupts = <6 IRQ_TYPE_EDGE_FALLING>;/*设置中断引脚为PH6,下降沿有效*/

        /*查看参考手册“Table 118”,EXTI[6]的事件输入号码为6*/

        /*中断类型和触发方式为下降沿触发*/

/*可以用interrupts-extended = <&gpioh 6 IRQ_TYPE_EDGE_FALLING>;替换上面两句*/

#sound-dai-cells = <1>;

status = "okay";

ports {

#address-cells = <1>;

#size-cells = <0>;

port@0 { /*port节点就是用来接收LTDC数据的接口*/

reg = <0>;

sii9022_in:endpoint {

remote-endpoint = <<dc_ep0_out>;

};

};

};

};

};

3.4、打开“stm32mp157d-atk.dts”,找到ltdc节点，内容如下：

<dc {

pinctrl-names = "default", "sleep";

pinctrl-0 = <<dc_pins_b>;/*pinctrl-0为default模式*/

pinctrl-1 = <<dc_pins_sleep_b>;/*pinctrl-1为sleep模式*/

/*设置了两个pinmux模式：pinctrl-0为default模式，pinctrl-1为sleep模式，

系统默认使用default模式。*/

status = "okay";

port {

#address-cells = <1>;

#size-cells = <0>;

ltdc_ep0_out: endpoint@0 { /*ltdc_ep0_out为port的子节点*/

reg = <0>;

remote-endpoint = <&rgb_panel_in>;

/*remote-endpoint属性告诉ltdc节点输出到rgb_panel_in接口*/

};

};

};

修改ltdc节点如下：

<dc {

pinctrl-names = "default", "sleep";

pinctrl-0 = <<dc_pins_b>;/*pinctrl-0为default模式*/

pinctrl-1 = <<dc_pins_sleep_b>;/*pinctrl-1为sleep模式*/

/*设置了两个pinmux模式：pinctrl-0为default模式，pinctrl-1为sleep模式，

系统默认使用default模式。*/

status = "okay";

port {

#address-cells = <1>;

#size-cells = <0>;

ltdc_ep0_out: endpoint@0 { /*ltdc_ep0_out为port的子节点*/

reg = <0>;

/*remote-endpoint = <&rgb_panel_in>;*/

/*remote-endpoint属性告诉ltdc节点输出到rgb_panel_in接口*/

remote-endpoint = <&sii9022_in>;

/*remote-endpoint属性告诉ltdc节点输出到sii9022_in接口*/

};

};

};

3.5、打开“stm32mp157d-atk.dts”,找到panel_rgb节点，内容如下：

panel_rgb: panel-rgb {

compatible = "zgq,lcd-rgb";

/*在 panel-simple.c 文件里的platform_of_match数组增加一个

of_device_id结构体，此结构体的compatible成员属性值为“zgq,lcd-rgb”。*/

backlight = <&backlight>;/*此属性值为引用背光节点*/

status = "okay";

port {

rgb_panel_in: endpoint {

remote-endpoint = <<dc_ep0_out>;

/*要从ltdc节点里获取显示数据*/

};

};

};

将“panel_rgb节点”屏蔽掉，如下：

/*

panel_rgb: panel-rgb {

compatible = "zgq,lcd-rgb";

//在 panel-simple.c 文件里的platform_of_match数组增加一个

//of_device_id结构体，此结构体的compatible成员属性值为“zgq,lcd-rgb”。

backlight = <&backlight>;//此属性值为引用背光节点

status = "okay";

port {

rgb_panel_in: endpoint {

remote-endpoint = <<dc_ep0_out>;

//要从ltdc节点里获取显示数据

};

};

};

*/

3.6、查看PH4，PH5，PH6和PA3是否被使用

打开设备树头文件“stm32mp15-pinctrl.dtsi”，查看PA11和PA12是否被使用了。

①点击“编辑”，点击“查找”，输入“STM32_PINMUX('H', 4”，然后“回车”，没有发现PH4被复用；

②点击“编辑”，点击“查找”，输入“STM32_PINMUX('H',5”，然后“回车”，发现PH5被复用，屏蔽该语句，见下图：

③点击“编辑”，点击“查找”，输入“STM32_PINMUX('H', 6”，然后“回车”，发现PH6被复用，屏蔽该语句，见下图：

④点击“编辑”，点击“查找”，输入“STM32_PINMUX('A', 3”，然后“回车”，发现PA3被复用，屏蔽该语句，见下图：

4、通过“linux内核图形化配置界面”，使能内核自带的sii902x驱动

1)、打开终端。

2)、输入“cd linux/atk-mp1/linux/my_linux/linux-5.4.31/回车”，切换到“linux/atk-mp1/linux/my_linux/linux-5.4.31/”目录；

3)、输入“make menuconfig回车”，打开linux内核图形化配置界面，移动向下光标键至“Device Drivers”，见下图：

4)、按下回车键，移动向下光标键至“Graphics support”，见下图：

5)、按下回车键，移动向下光标键至“Display Interface Bridges”，见下图：

6)、按下回车键，移动向下光标键至“Silicon Image sii902x RGB/HDMI bridge”，见下图：

7)、按“Y”

8)、先“保存”，按“TAB键”至“Save”,按下“回车键”，得到下面的界面。

9)、输入“./arch/arm/configs/stm32mp1_atk_defconfig”，移动“向下光标键”至“Ok”，得到下图：

10)、按“回车键”,保存完成。得到下面的界面。

11)、按“回车键”，退出保存界面。然后按“ESC键”，直到得到下面的界面：

12)、输入“make stm32mp1_atk_defconfig回车”，注意：如果忘记执行，可能再次打开时会发现“.config”没有被更新，得到下图：

5、编译设备树

①打开VSCode中的终端，输入“make uImage dtbs LOADADDR=0XC2000040 -j8回车”，执行编译“Image”和“dtbs”，并指定装载的起始地址为0XC2000040，j8表示指定采用8线程执行。“make dtbs”，用来指定编译设备树。见下图：

②输入“ls arch/arm/boot/uImage -l”

查看是否生成了新的“uImage”文件

③输入“ls arch/arm/boot/dts/stm32mp157d-atk.dtb -l”

查看是否生成了新的“stm32mp157d-atk.dtb”文件

4)、拷贝输出的文件：

①输入“cp arch/arm/boot/uImage /home/zgq/linux/atk-mp1/linux/bootfs/ -f回车”，执行文件拷贝，准备烧录到EMMC；

②输入“cp arch/arm/boot/dts/stm32mp157d-atk.dtb /home/zgq/linux/atk-mp1/linux/bootfs/ -f回车”，执行文件拷贝，准备烧录到EMMC

③输入“cp arch/arm/boot/uImage /home/zgq/linux/tftpboot/ -f回车”，执行文件拷贝，准备从tftp下载；

④输入“cp arch/arm/boot/dts/stm32mp157d-atk.dtb /home/zgq/linux/tftpboot/ -f回车”，执行文件拷贝，准备从tftp下载；

⑤输入“ls -l /home/zgq/linux/atk-mp1/linux/bootfs/回车”，查看“/home/zgq/linux/atk-mp1/linux/bootfs/”目录下的所有文件和文件夹

⑥输入“ls -l /home/zgq/linux/tftpboot/回车”，查看“/home/zgq/linux/tftpboot/”目录下的所有文件和文件夹

⑦输入“chmod 777 /home/zgq/linux/tftpboot/stm32mp157d-atk.dtb回车”

给“stm32mp157d-atk.dtb”文件赋予可执行权限

⑧输入“chmod 777 /home/zgq/linux/tftpboot/uImage回车” ,给“uImage”文件赋予可执行权限

⑨输入“ls /home/zgq/linux/tftpboot/ -l回车”，查看“/home/zgq/linux/tftpboot/”目录下的所有文件和文件夹

6、测试程序

#include <linux/gpio/consumer.h>
#include <linux/i2c-mux.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <linux/regmap.h>
#include <linux/clk.h>
#include <linux/regulator/consumer.h>#include <drm/drm_atomic_helper.h>
#include <drm/drm_drv.h>
#include <drm/drm_edid.h>
#include <drm/drm_print.h>
#include <drm/drm_probe_helper.h>#include <sound/hdmi-codec.h>#define SII902X_TPI_VIDEO_DATA			0x0#define SII902X_TPI_PIXEL_REPETITION		0x8 /*TPI输入总线和像素重复数据寄存器地址为0x08*/
#define SII902X_TPI_AVI_PIXEL_REP_BUS_24BIT     BIT(5) /*输入总线选择：bit5=0半像素宽;bit5=1全像素宽*/
#define SII902X_TPI_AVI_PIXEL_REP_RISING_EDGE   BIT(4) /*边沿选择：bit4=0下降沿;bit4=1上升沿*/
#define SII902X_TPI_AVI_PIXEL_REP_4X		3  /*像素重复因子：PR[3:0]=0011b,每个像素发送4次*/
#define SII902X_TPI_AVI_PIXEL_REP_2X		1  /*像素重复因子：PR[3:0]=0001b,每个像素发送2次*/
#define SII902X_TPI_AVI_PIXEL_REP_NONE		0  /*像素重复因子：PR[3:0]=0000b,每个像素发送1次，不用重复发送*/
#define SII902X_TPI_CLK_RATIO_HALF		(0 << 6) /*bit7:6=00b,TCLK选择0.5倍的速度*/
#define SII902X_TPI_CLK_RATIO_1X		(1 << 6) /*bit7:6=01b,TCLK选择1倍的速度*/
#define SII902X_TPI_CLK_RATIO_2X		(2 << 6) /*bit7:6=10b,TCLK选择2倍的速度*/
#define SII902X_TPI_CLK_RATIO_4X		(3 << 6) /*bit7:6=11b,TCLK选择4倍的速度*/#define SII902X_TPI_AVI_IN_FORMAT		0x9 /*TPI AVI输入和输出格式数据配置寄存器地址为0x09*/
#define SII902X_TPI_AVI_INPUT_BITMODE_12BIT	BIT(7)
#define SII902X_TPI_AVI_INPUT_DITHER		BIT(6)
/*bit7:6=00b,输入颜色深度8位*/
/*bit7:6=01b,没有定义"输入颜色深度"*/
/*颜色抖动则是尝试用较低的颜色位深度来获得更为丰富的视觉效果,
比如用1位的位深度来尽可能得到8位的视觉效果*/
/*bit7:6=10b,输入颜色深度10/12位,在4:2:2模式中，无"颜色抖动"*/
/*bit7:6=11b,输入颜色深度10/12位,在4:2:2模式中，"颜色抖动"为8位的视觉效果**/
#define SII902X_TPI_AVI_INPUT_RANGE_LIMITED	(2 << 2) /*bit3:2=10b,关闭视频范围扩展*/
#define SII902X_TPI_AVI_INPUT_RANGE_FULL	(1 << 2) /*bit3:2=01b,打开视频范围扩展*/
#define SII902X_TPI_AVI_INPUT_RANGE_AUTO	(0 << 2) /*bit3:2=00b,自动选择"视频范围扩展"*/
#define SII902X_TPI_AVI_INPUT_COLORSPACE_BLACK	(3 << 0) /*bit1:0=11b,输入色彩为Black模式*/
#define SII902X_TPI_AVI_INPUT_COLORSPACE_YUV422	(2 << 0) /*bit1:0=10b,输入色彩为YCbCr 4:2:2模式*/
#define SII902X_TPI_AVI_INPUT_COLORSPACE_YUV444	(1 << 0) /*bit1:0=01b,输入色彩为YCbCr 4:4:4模式*/
#define SII902X_TPI_AVI_INPUT_COLORSPACE_RGB	(0 << 0) /*bit1:0=01b,输入色彩为RGB模式*/#define SII902X_TPI_AVI_INFOFRAME		0x0c
/*"AVI信息帧寄存器"起始地址为0x0C*/
/*用来存放"AVI信息帧校验和"*/#define SII902X_SYS_CTRL_DATA			0x1a /*系统控制寄存器地址为0x1A*/
#define SII902X_SYS_CTRL_PWR_DWN		BIT(4)
/*bit4=0b,TDMS输出控制激活;bit4=1b,TDMS输出控制关闭*/
#define SII902X_SYS_CTRL_AV_MUTE		BIT(3)
/*bit3=0b,普通的音视频，指同时包含音频和视频内容的媒体形式;*/
/*bit3=1b,配置为音频和视频接收器*/
#define SII902X_SYS_CTRL_DDC_BUS_REQ		BIT(2)
/*bit2=0b,主机无需请求使用DDC总线*/
/*bit2=1b,主机请求使用DDC总线*/
#define SII902X_SYS_CTRL_DDC_BUS_GRTD		BIT(1)
/*bit1=0b,DDC总线不可用*/
/*bit1=1b,主机可以写DDC总线*/
#define SII902X_SYS_CTRL_OUTPUT_MODE		BIT(0)
/*bit0=0b,输出模式选择为DVI,bit0=1b,输出模式选择为HDMI*/
#define SII902X_SYS_CTRL_OUTPUT_HDMI	1 /*bit0=1b,输出模式选择为HDMI*/
#define SII902X_SYS_CTRL_OUTPUT_DVI		0 /*bit0=0b,输出模式选择为DVI*/#define SII902X_REG_CHIPID(n)			(0x1b + (n))
/*地址范围0x1B～0x1D，保存的是TPI芯片的ID和版本*/#define SII902X_PWR_STATE_CTRL			0x1e /*TPI设备电源状态控制数据寄存器地址为0x1E*/
#define SII902X_AVI_POWER_STATE_MSK		GENMASK(1, 0)  /*结果为0x03*/
#define SII902X_AVI_POWER_STATE_D(l)	((l) & SII902X_AVI_POWER_STATE_MSK)
/*执行SII902X_AVI_POWER_STATE_D(0);//结果为0x00*/
/*Power_state[1:0] = 00b，配置"全功率操作模式"*//* Audio  */
#define SII902X_TPI_I2S_ENABLE_MAPPING_REG	0x1f  /*Audio配置寄存器起始地址为0x1F*/
#define SII902X_TPI_I2S_CONFIG_FIFO0		(0 << 0) /*bit1:0=00b,FIFO使用通道0*/
#define SII902X_TPI_I2S_CONFIG_FIFO1		(1 << 0) /*bit1:0=01b,FIFO使用通道1*/
#define SII902X_TPI_I2S_CONFIG_FIFO2		(2 << 0) /*bit1:0=10b,FIFO使用通道2*/
#define SII902X_TPI_I2S_CONFIG_FIFO3		(3 << 0) /*bit1:0=11b,FIFO使用通道3*/
#define SII902X_TPI_I2S_LEFT_RIGHT_SWAP		(1 << 2)
/*bit2=0b,I2S左右通道不用交换;*/
/*bit2=1b,I2S左右通道交换*/
#define SII902X_TPI_I2S_AUTO_DOWNSAMPLE		(1 << 3)
/*bit3=0b,FIFO使用通道0不用自动下采样到"基本音频模式"*/
/*bit3=1b,FIFO使用通道0会自动下采样到"基本音频模式"*/
#define SII902X_TPI_I2S_SELECT_SD0			(0 << 4) /*bit5:4=00b,选择SD0引脚*/
#define SII902X_TPI_I2S_SELECT_SD1			(1 << 4) /*bit5:4=01b,选择SD1引脚*/
#define SII902X_TPI_I2S_SELECT_SD2			(2 << 4) /*bit5:4=10b,选择SD2引脚*/
#define SII902X_TPI_I2S_SELECT_SD3			(3 << 4) /*bit5:4=11b,选择SD3引脚*/
#define SII902X_TPI_I2S_FIFO_ENABLE			(1 << 7)
/*bit7=0b,不使能"SD引脚"选择;*/
/*bit7=1b,使能"SD引脚"选择;*/#define SII902X_TPI_I2S_INPUT_CONFIG_REG	0x20 /*I2S输入配置寄存器的地址为0x20*/
#define SII902X_TPI_I2S_FIRST_BIT_SHIFT_YES		(0 << 0) /*bit0=0b,将WS转换为SD，第1位要移位*/
#define SII902X_TPI_I2S_FIRST_BIT_SHIFT_NO		(1 << 0) /*bit0=1b,将WS转换为SD，第1位不用移位*/
#define SII902X_TPI_I2S_SD_DIRECTION_MSB_FIRST	(0 << 1) /*bit1=0b,字节移位第1位为最高位*/
#define SII902X_TPI_I2S_SD_DIRECTION_LSB_FIRST	(1 << 1) /*bit1=1b,字节移位第1位为最低位*/
#define SII902X_TPI_I2S_SD_JUSTIFY_LEFT			(0 << 2) /*bit2=0b,数据左对齐*/
#define SII902X_TPI_I2S_SD_JUSTIFY_RIGHT		(1 << 2) /*bit2=1b,数据右对齐*/
#define SII902X_TPI_I2S_WS_POLARITY_LOW			(0 << 3) /*bit3=0b,WS极性为LOW*/
#define SII902X_TPI_I2S_WS_POLARITY_HIGH		(1 << 3) /*bit3=1b,WS极性为HIGH*/
#define SII902X_TPI_I2S_MCLK_MULTIPLIER_128		(0 << 4) /*bit6:4=000b,MCLK乘数为128*/
#define SII902X_TPI_I2S_MCLK_MULTIPLIER_256		(1 << 4) /*bit6:4=001b,MCLK乘数为256*/
#define SII902X_TPI_I2S_MCLK_MULTIPLIER_384		(2 << 4) /*bit6:4=010b,MCLK乘数为384*/
#define SII902X_TPI_I2S_MCLK_MULTIPLIER_512		(3 << 4) /*bit6:4=011b,MCLK乘数为512*/
#define SII902X_TPI_I2S_MCLK_MULTIPLIER_768		(4 << 4) /*bit6:4=100b,MCLK乘数为768*/
#define SII902X_TPI_I2S_MCLK_MULTIPLIER_1024	(5 << 4) /*bit6:4=101b,MCLK乘数为1024*/
#define SII902X_TPI_I2S_MCLK_MULTIPLIER_1152	(6 << 4) /*bit6:4=110b,MCLK乘数为1152*/
#define SII902X_TPI_I2S_MCLK_MULTIPLIER_192		(7 << 4) /*bit6:4=111b,MCLK乘数为192*/
#define SII902X_TPI_I2S_SCK_EDGE_FALLING		(0 << 7) /*bit7=0b,SCK采样边沿为下降沿*/
#define SII902X_TPI_I2S_SCK_EDGE_RISING			(1 << 7) /*bit7=1b,SCK采样边沿为上升沿*/#define SII902X_TPI_I2S_STRM_HDR_BASE	0x21 /*I2S通道状态寄存器起始地址为0x21*/
#define SII902X_TPI_I2S_STRM_HDR_SIZE	5    /*I2S通道状态寄存器数量为5*/#define SII902X_TPI_AUDIO_CONFIG_BYTE2_REG	0x26 /*TPI Audio配置寄存器地址为0x26*/
#define SII902X_TPI_AUDIO_CODING_STREAM_HEADER	(0 << 0) /*CT[3:0]=0000b,音频配置类型参考流头*/
#define SII902X_TPI_AUDIO_CODING_PCM			(1 << 0) /*CT[3:0]=0001b,音频配置类型为PCM*/
#define SII902X_TPI_AUDIO_CODING_AC3			(2 << 0) /*CT[3:0]=0010b,音频配置类型为AC-3*/
#define SII902X_TPI_AUDIO_CODING_MPEG1			(3 << 0) /*CT[3:0]=0011b,音频配置类型为MPEG1*/
#define SII902X_TPI_AUDIO_CODING_MP3			(4 << 0) /*CT[3:0]=0100b,音频配置类型为MP3*/
#define SII902X_TPI_AUDIO_CODING_MPEG2			(5 << 0) /*CT[3:0]=0101b,音频配置类型为MPED2*/
#define SII902X_TPI_AUDIO_CODING_AAC			(6 << 0) /*CT[3:0]=0110b,音频配置类型为AAC*/
#define SII902X_TPI_AUDIO_CODING_DTS			(7 << 0) /*CT[3:0]=0111b,音频配置类型为DTS*/
#define SII902X_TPI_AUDIO_CODING_ATRAC			(8 << 0) /*CT[3:0]=1000b,音频配置类型为ATRAC*/
#define SII902X_TPI_AUDIO_MUTE_DISABLE			(0 << 4) /*Mute=0b表示普通音*/
#define SII902X_TPI_AUDIO_MUTE_ENABLE			(1 << 4) /*Mute=1b表示使用弱音器*/
#define SII902X_TPI_AUDIO_LAYOUT_2_CHANNELS		(0 << 5) /*Layout=0b,表示音频包头布局指示器0*/
#define SII902X_TPI_AUDIO_LAYOUT_8_CHANNELS		(1 << 5) /*Layout=1b,表示音频包头布局指示器1*/
#define SII902X_TPI_AUDIO_INTERFACE_DISABLE		(0 << 6) /*00b，表示不使用Audio接口*/
#define SII902X_TPI_AUDIO_INTERFACE_SPDIF		(1 << 6) /*01b，表示Audio接口使用S/PDIF*/
#define SII902X_TPI_AUDIO_INTERFACE_I2S			(2 << 6) /*10b，表示Audio接口使用I2S*/#define SII902X_TPI_AUDIO_CONFIG_BYTE3_REG	0x27 /*TPI Audio配置寄存器地址为0x27*/
#define SII902X_TPI_AUDIO_FREQ_STREAM	(0 << 3) /*SF[2:0]=000b,Audio采样频率参考流头;*/
#define SII902X_TPI_AUDIO_FREQ_32KHZ	(1 << 3) /*SF[2:0]=001b,Audio采样频率为32KHz;*/
#define SII902X_TPI_AUDIO_FREQ_44KHZ	(2 << 3) /*SF[2:0]=010b,Audio采样频率为44.1KHz;*/
#define SII902X_TPI_AUDIO_FREQ_48KHZ	(3 << 3) /*SF[2:0]=011b,Audio采样频率为48KHz;*/
#define SII902X_TPI_AUDIO_FREQ_88KHZ	(4 << 3) /*SF[2:0]=100b,Audio采样频率为88.2KHz;*/
#define SII902X_TPI_AUDIO_FREQ_96KHZ	(5 << 3) /*SF[2:0]=101b,Audio采样频率为96KHz;*/
#define SII902X_TPI_AUDIO_FREQ_176KHZ	(6 << 3) /*SF[2:0]=110b,Audio采样频率为176.4KHz;*/
#define SII902X_TPI_AUDIO_FREQ_192KHZ	(7 << 3) /*SF[2:0]=111b,Audio采样频率为192KHz;*/
#define SII902X_TPI_AUDIO_SAMPLE_SIZE_STREAM	(0 << 6) /*SS[1:0]=00,Audio采样位数参考流头;*/
#define SII902X_TPI_AUDIO_SAMPLE_SIZE_16		(1 << 6) /*SS[1:0]=01,Audio采样位数为16位;*/
#define SII902X_TPI_AUDIO_SAMPLE_SIZE_20		(2 << 6) /*SS[1:0]=10,Audio采样位数为20位;*/
#define SII902X_TPI_AUDIO_SAMPLE_SIZE_24		(3 << 6) /*SS[1:0]=1q,Audio采样位数为24位;*/#define SII902X_TPI_AUDIO_CONFIG_BYTE4_REG	0x28
/*Audio配置寄存器结束地址为0x28，保留不用*/#define SII902X_INT_ENABLE			0x3c  /*"中断使能寄存器"起始地址为0x3C*/
#define SII902X_INT_STATUS			0x3d  /*"中断状态寄存器"结束地址为0x3D*/
#define SII902X_HOTPLUG_EVENT		BIT(0) /*"中断使能寄存器"bit0=1,即使能sii902x输出中断*/
#define SII902X_PLUGGED_STATUS		BIT(2) /*"中断状态寄存器"bit2=1,表示产生中断*/#define SII902X_REG_TPI_RQB			0xc7
/*复位和初始化寄存器地址为0xC7*/
/*复位芯片，接着向地址0xC7的寄存器写入0x00，使能TPI模式*//*间接内部寄存器访问,Indirect internal register access*/
#define SII902X_IND_SET_PAGE	0xbc /*页寄存器地址为0xBC*/
#define SII902X_IND_OFFSET		0xbd /*变址寄存器地址为0xBD*/
#define SII902X_IND_VALUE		0xbe
/*由页寄存器和变址寄存器选中的寄存器，即为当前寄存器(其固定地址为0xBE)*/#define SII902X_TPI_MISC_INFOFRAME_BASE		0xbf
/*"TPI杂项信息帧数据寄存器"起始地址为0xBF*/
#define SII902X_TPI_MISC_INFOFRAME_END		0xde
/*"TPI杂项信息帧数据寄存器"结束地址为0xDE*/
#define SII902X_TPI_MISC_INFOFRAME_SIZE	\(SII902X_TPI_MISC_INFOFRAME_END - SII902X_TPI_MISC_INFOFRAME_BASE)
/*"其它信息帧寄存器"的数量，感觉这里少了1个？？？*/#define SII902X_I2C_BUS_ACQUISITION_TIMEOUT_MS	500#define SII902X_AUDIO_PORT_INDEX		3/* CEC device */
#define SII902X_CEC_I2C_ADDR	0x30#define SII902X_CEC_SETUP			0x8estruct sii902x {struct i2c_client *i2c;/*i2c设备*/struct regmap *regmap;struct drm_bridge bridge;struct drm_connector connector;struct gpio_desc *reset_gpio;struct i2c_mux_core *i2cmux;struct edid *edid;/** Mutex protects audio and video functions from interfering* each other, by keeping their i2c command sequences atomic.*/struct mutex mutex;/*声明互斥体mutex*/struct sii902x_audio {struct platform_device *pdev;struct clk *mclk;u32 i2s_fifo_sequence[4];} audio;struct regulator_bulk_data supplies[2];
};//函数功能：通过I2C读取地址为reg寄存器的值，返回值在首地址为val的存储区中
static int sii902x_read_unlocked(struct i2c_client *i2c, u8 reg, u8 *val)
{union i2c_smbus_data data;int ret;ret = __i2c_smbus_xfer(i2c->adapter, i2c->addr, i2c->flags,I2C_SMBUS_READ, reg, I2C_SMBUS_BYTE_DATA, &data);/*在12C总线上传输数据，支持多种传输类型，如字节读写、块读写等。如果成功,则返回传输的字节数，否则返回一个负数。*/if (ret < 0)return ret;*val = data.byte;//保存“地址为reg寄存器的值”return 0;
}//函数功能：通过I2C，将val的值写入地址为reg寄存器中
static int sii902x_write_unlocked(struct i2c_client *i2c, u8 reg, u8 val)
{union i2c_smbus_data data;data.byte = val;return __i2c_smbus_xfer(i2c->adapter, i2c->addr, i2c->flags,I2C_SMBUS_WRITE, reg, I2C_SMBUS_BYTE_DATA,&data);/*在12C总线上传输数据，支持多种传输类型，如字节读写、块读写等。如果成功,则返回传输的字节数，否则返回一个负数。*/
}//函数功能：通过I2C，修改地址为reg寄存器中的mask位
static int sii902x_update_bits_unlocked(struct i2c_client *i2c, u8 reg, u8 mask,u8 val)
{int ret;u8 status;ret = sii902x_read_unlocked(i2c, reg, &status);/*通过I2C读取地址为reg寄存器的值，返回值在status中*/if (ret)return ret;status &= ~mask;status |= val & mask;return sii902x_write_unlocked(i2c, reg, status);/*通过I2C，将status的值写入地址为reg寄存器中*/
}static inline struct sii902x *bridge_to_sii902x(struct drm_bridge *bridge)
{return container_of(bridge, struct sii902x, bridge);
}static inline struct sii902x *connector_to_sii902x(struct drm_connector *con)
{return container_of(con, struct sii902x, connector);
}//函数功能：sii902复位
static void sii902x_reset(struct sii902x *sii902x)
{if (!sii902x->reset_gpio)return;gpiod_set_value(sii902x->reset_gpio, 1);/*1表示设置引脚输出高电平*//* The datasheet says treset-min = 100us. Make it 150us to be sure. */usleep_range(150, 200);/*睡大约一段时间150us~200us*/gpiod_set_value(sii902x->reset_gpio, 0);/*0表示设置引脚输出低电平*/
}//函数功能：读"中断状态寄存器"bit2
//返回值为1，表示HDMI已经连接;
//返回值为2，表示HDMI没有连接;
static enum drm_connector_status
sii902x_connector_detect(struct drm_connector *connector, bool force)
{struct sii902x *sii902x = connector_to_sii902x(connector);unsigned int status;mutex_lock(&sii902x->mutex);/*上锁*/regmap_read(sii902x->regmap, SII902X_INT_STATUS, &status);/*读"中断状态寄存器"bit2，地址为0x3D，返回值保存到status中"*/mutex_unlock(&sii902x->mutex);/*解锁*/return (status & SII902X_PLUGGED_STATUS) ?connector_status_connected : connector_status_disconnected;/*"中断状态寄存器"bit2=1,表示产生中断*/
}static const struct drm_connector_funcs sii902x_connector_funcs = {.detect = sii902x_connector_detect,/*读"中断状态寄存器"bit2*/.fill_modes = drm_helper_probe_single_connector_modes,/*获得完整的显示模式*/.destroy = drm_connector_cleanup,/*清除初始化的连接器*/.reset = drm_atomic_helper_connector_reset,.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
};static int sii902x_get_modes(struct drm_connector *connector)
{struct sii902x *sii902x = connector_to_sii902x(connector);u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;u8 output_mode = SII902X_SYS_CTRL_OUTPUT_DVI;struct edid *edid;int num = 0, ret;mutex_lock(&sii902x->mutex);/*上锁*/kfree(sii902x->edid);/*在Linux内核中，kfree是一个用于释放内存的函数，它用于释放通过kmalloc、kzalloc、vmalloc等函数分配的内存。这些分配函数在内核空间中动态地分配内存，而kfree则用于在不再需要这些内存时将其释放回系统。*/sii902x->edid = NULL;edid = drm_get_edid(connector, sii902x->i2cmux->adapter[0]);drm_connector_update_edid_property(connector, edid);if (edid) {if (drm_detect_hdmi_monitor(edid))output_mode = SII902X_SYS_CTRL_OUTPUT_HDMI;/*bit0=1b,输出模式选择为HDMI*/num = drm_add_edid_modes(connector, edid);sii902x->edid = edid;}ret = drm_display_info_set_bus_formats(&connector->display_info,&bus_format, 1);if (ret)goto error_out;ret = regmap_update_bits(sii902x->regmap, SII902X_SYS_CTRL_DATA,SII902X_SYS_CTRL_OUTPUT_MODE, output_mode);/*系统控制寄存器(地址为0x1A),将bit0=1b,输出模式选择为HDMI*/if (ret)goto error_out;ret = num;error_out:mutex_unlock(&sii902x->mutex);/*解锁*/return ret;
}static enum drm_mode_status sii902x_mode_valid(struct drm_connector *connector,struct drm_display_mode *mode)
{/* TODO: check mode */return MODE_OK;
}static const struct drm_connector_helper_funcs sii902x_connector_helper_funcs = {.get_modes = sii902x_get_modes,.mode_valid = sii902x_mode_valid,
};//函数功能：关闭"TDMS输出控制"
static void sii902x_bridge_disable(struct drm_bridge *bridge)
{struct sii902x *sii902x = bridge_to_sii902x(bridge);mutex_lock(&sii902x->mutex);/*上锁*/regmap_update_bits(sii902x->regmap, SII902X_SYS_CTRL_DATA,SII902X_SYS_CTRL_PWR_DWN,SII902X_SYS_CTRL_PWR_DWN);/*系统控制寄存器地址为0x1A,设置bit4=1b,TDMS输出控制关闭*/mutex_unlock(&sii902x->mutex);/*解锁*/
}static void sii902x_bridge_enable(struct drm_bridge *bridge)
{struct sii902x *sii902x = bridge_to_sii902x(bridge);u8 output_mode = SII902X_SYS_CTRL_OUTPUT_DVI;mutex_lock(&sii902x->mutex);/*上锁*/regmap_update_bits(sii902x->regmap, SII902X_PWR_STATE_CTRL,SII902X_AVI_POWER_STATE_MSK,SII902X_AVI_POWER_STATE_D(0));/*TPI设备电源状态控制数据寄存器地址为0x1E*//*Power_state[1:0] = 00b，配置"全功率操作模式"*/regmap_update_bits(sii902x->regmap, SII902X_SYS_CTRL_DATA,SII902X_SYS_CTRL_PWR_DWN, 0);/*系统控制寄存器地址为0x1A,设置bit4=0b,打开TDMS输出控制*/if (sii902x->edid) {if (drm_detect_hdmi_monitor(sii902x->edid))output_mode = SII902X_SYS_CTRL_OUTPUT_HDMI;}regmap_update_bits(sii902x->regmap, SII902X_SYS_CTRL_DATA,SII902X_SYS_CTRL_OUTPUT_MODE, output_mode);mutex_unlock(&sii902x->mutex);/*解锁*/
}static void sii902x_bridge_mode_set(struct drm_bridge *bridge,const struct drm_display_mode *mode,const struct drm_display_mode *adj)
{struct sii902x *sii902x = bridge_to_sii902x(bridge);struct regmap *regmap = sii902x->regmap;u8 buf[HDMI_INFOFRAME_SIZE(AVI)];struct hdmi_avi_infoframe frame;u16 pixel_clock_10kHz = adj->clock / 10;int ret;buf[0] = pixel_clock_10kHz & 0xff;buf[1] = pixel_clock_10kHz >> 8;buf[2] = adj->vrefresh;buf[3] = 0x00;buf[4] = adj->hdisplay;buf[5] = adj->hdisplay >> 8;buf[6] = adj->vdisplay;buf[7] = adj->vdisplay >> 8;buf[8] = SII902X_TPI_CLK_RATIO_1X | SII902X_TPI_AVI_PIXEL_REP_NONE | SII902X_TPI_AVI_PIXEL_REP_BUS_24BIT;/*buf[8]为"TPI输入总线和像素重复数据寄存器"中的配置数据，其寄存器地址为0x08*//*bit7:6=01b,TCLK选择1倍的速度;*//*像素重复因子：PR[3:0]=0000b,每个像素发送1次，不用重复发送*//*输入总线选择：bit5=1全像素宽*/buf[9] = SII902X_TPI_AVI_INPUT_RANGE_AUTO | SII902X_TPI_AVI_INPUT_COLORSPACE_RGB;/*buf[9]为TPI AVI输入和输出格式数据配置寄存器中的配置数据，其寄存器地址为0x09*//*bit3:2=00b,自动选择"视频范围扩展"*//*bit1:0=01b,输入色彩为RGB模式*/mutex_lock(&sii902x->mutex);/*上锁*/ret = regmap_bulk_write(regmap, SII902X_TPI_VIDEO_DATA, buf, 10);/*向设备写入多个寄存器*//*sii902x寄存器首地址为0x00*//*待数据的首地址为buf*//*写入的字节数量为10*/if (ret)goto out;ret = drm_hdmi_avi_infoframe_from_display_mode(&frame,&sii902x->connector, adj);if (ret < 0) {DRM_ERROR("couldn't fill AVI infoframe\n");goto out;}ret = hdmi_avi_infoframe_pack(&frame, buf, sizeof(buf));if (ret < 0) {DRM_ERROR("failed to pack AVI infoframe: %d\n", ret);goto out;}/* Do not send the infoframe header, but keep the CRC field. */regmap_bulk_write(regmap, SII902X_TPI_AVI_INFOFRAME,buf + HDMI_INFOFRAME_HEADER_SIZE - 1,HDMI_AVI_INFOFRAME_SIZE + 1);/*向设备写入多个寄存器*//*sii902x寄存器首地址为0x0C*//*待数据的首地址为(buf + HDMI_INFOFRAME_HEADER_SIZE - 1)*//*写入的字节数量为(HDMI_AVI_INFOFRAME_SIZE+1)*/out:mutex_unlock(&sii902x->mutex);/*解锁*/
}static int sii902x_bridge_attach(struct drm_bridge *bridge)
{struct sii902x *sii902x = bridge_to_sii902x(bridge);struct drm_device *drm = bridge->dev;int ret;drm_connector_helper_add(&sii902x->connector,&sii902x_connector_helper_funcs);/*为连接器设置helper虚值表*/if (!drm_core_check_feature(drm, DRIVER_ATOMIC)) {/*检查驱动程序特性标志*/dev_err(&sii902x->i2c->dev,"sii902x driver is only compatible with DRM devices supporting atomic updates\n");return -ENOTSUPP;}ret = drm_connector_init(drm, &sii902x->connector,&sii902x_connector_funcs,DRM_MODE_CONNECTOR_HDMIA);/*初始化一个预分配的连接器*/if (ret)return ret;if (sii902x->i2c->irq > 0)sii902x->connector.polled = DRM_CONNECTOR_POLL_HPD;elsesii902x->connector.polled = DRM_CONNECTOR_POLL_CONNECT;drm_connector_attach_encoder(&sii902x->connector, bridge->encoder);/*将连接器连接到编码器上*/return 0;
}static const struct drm_bridge_funcs sii902x_bridge_funcs = {.attach = sii902x_bridge_attach,.mode_set = sii902x_bridge_mode_set,.disable = sii902x_bridge_disable,.enable = sii902x_bridge_enable,
};//mute=1,修改"TPI Audio配置寄存器(地址为0x26)"的bit4为1,使能乐器声音为柔和的
//mute=0,修改"TPI Audio配置寄存器(地址为0x26)"的bit4为0,不使能乐器声音为柔和的
static int sii902x_mute(struct sii902x *sii902x, bool mute)
{struct device *dev = &sii902x->i2c->dev;unsigned int val = mute ? SII902X_TPI_AUDIO_MUTE_ENABLE :SII902X_TPI_AUDIO_MUTE_DISABLE;dev_dbg(dev, "%s: %s\n", __func__, mute ? "Muted" : "Unmuted");return regmap_update_bits(sii902x->regmap,SII902X_TPI_AUDIO_CONFIG_BYTE2_REG,SII902X_TPI_AUDIO_MUTE_ENABLE, val);/*mute=1,修改"TPI Audio配置寄存器(地址为0x26)"的bit4为1,使能乐器声音为柔和的*//*mute=0,修改"TPI Audio配置寄存器(地址为0x26)"的bit4为0,不使能乐器声音为柔和的*/
}static const int sii902x_mclk_div_table[] = {128, 256, 384, 512, 768, 1024, 1152, 192 };static int sii902x_select_mclk_div(u8 *i2s_config_reg, unsigned int rate,unsigned int mclk)
{int div = mclk / rate;int distance = 100000;u8 i, nearest = 0;for (i = 0; i < ARRAY_SIZE(sii902x_mclk_div_table); i++) {unsigned int d = abs(div - sii902x_mclk_div_table[i]);if (d >= distance)continue;nearest = i;distance = d;if (d == 0)break;}*i2s_config_reg |= nearest << 4;return sii902x_mclk_div_table[nearest];
}static const struct sii902x_sample_freq {u32 freq;u8 val;
} sii902x_sample_freq[] = {{ .freq = 32000,	.val = SII902X_TPI_AUDIO_FREQ_32KHZ },{ .freq = 44000,	.val = SII902X_TPI_AUDIO_FREQ_44KHZ },{ .freq = 48000,	.val = SII902X_TPI_AUDIO_FREQ_48KHZ },{ .freq = 88000,	.val = SII902X_TPI_AUDIO_FREQ_88KHZ },{ .freq = 96000,	.val = SII902X_TPI_AUDIO_FREQ_96KHZ },{ .freq = 176000,	.val = SII902X_TPI_AUDIO_FREQ_176KHZ },{ .freq = 192000,	.val = SII902X_TPI_AUDIO_FREQ_192KHZ },
};static int sii902x_audio_hw_params(struct device *dev, void *data,struct hdmi_codec_daifmt *daifmt,struct hdmi_codec_params *params)
{struct sii902x *sii902x = dev_get_drvdata(dev);u8 i2s_config_reg = SII902X_TPI_I2S_SD_DIRECTION_MSB_FIRST;u8 config_byte2_reg = (SII902X_TPI_AUDIO_INTERFACE_I2S |SII902X_TPI_AUDIO_MUTE_ENABLE |SII902X_TPI_AUDIO_CODING_PCM);u8 config_byte3_reg = 0;u8 infoframe_buf[HDMI_INFOFRAME_SIZE(AUDIO)];unsigned long mclk_rate;int i, ret;if (daifmt->bit_clk_master || daifmt->frame_clk_master) {dev_dbg(dev, "%s: I2S master mode not supported\n", __func__);return -EINVAL;}switch (daifmt->fmt) {case HDMI_I2S:i2s_config_reg |= SII902X_TPI_I2S_FIRST_BIT_SHIFT_YES |SII902X_TPI_I2S_SD_JUSTIFY_LEFT;break;case HDMI_RIGHT_J:i2s_config_reg |= SII902X_TPI_I2S_SD_JUSTIFY_RIGHT;break;case HDMI_LEFT_J:i2s_config_reg |= SII902X_TPI_I2S_SD_JUSTIFY_LEFT;break;default:dev_dbg(dev, "%s: Unsupported i2s format %u\n", __func__,daifmt->fmt);return -EINVAL;}if (daifmt->bit_clk_inv)i2s_config_reg |= SII902X_TPI_I2S_SCK_EDGE_FALLING;elsei2s_config_reg |= SII902X_TPI_I2S_SCK_EDGE_RISING;if (daifmt->frame_clk_inv)i2s_config_reg |= SII902X_TPI_I2S_WS_POLARITY_LOW;elsei2s_config_reg |= SII902X_TPI_I2S_WS_POLARITY_HIGH;if (params->channels > 2)config_byte2_reg |= SII902X_TPI_AUDIO_LAYOUT_8_CHANNELS;elseconfig_byte2_reg |= SII902X_TPI_AUDIO_LAYOUT_2_CHANNELS;switch (params->sample_width) {case 16:config_byte3_reg |= SII902X_TPI_AUDIO_SAMPLE_SIZE_16;break;case 20:config_byte3_reg |= SII902X_TPI_AUDIO_SAMPLE_SIZE_20;break;case 24:case 32:config_byte3_reg |= SII902X_TPI_AUDIO_SAMPLE_SIZE_24;break;default:dev_err(dev, "%s: Unsupported sample width %u\n", __func__,params->sample_width);return -EINVAL;}for (i = 0; i < ARRAY_SIZE(sii902x_sample_freq); i++) {if (params->sample_rate == sii902x_sample_freq[i].freq) {config_byte3_reg |= sii902x_sample_freq[i].val;break;}}ret = clk_prepare_enable(sii902x->audio.mclk);if (ret) {dev_err(dev, "Enabling mclk failed: %d\n", ret);return ret;}if (sii902x->audio.mclk) {mclk_rate = clk_get_rate(sii902x->audio.mclk);ret = sii902x_select_mclk_div(&i2s_config_reg,params->sample_rate, mclk_rate);if (mclk_rate != ret * params->sample_rate)dev_dbg(dev, "Inaccurate reference clock (%ld/%d != %u)\n",mclk_rate, ret, params->sample_rate);}mutex_lock(&sii902x->mutex);/*上锁*/ret = regmap_write(sii902x->regmap,SII902X_TPI_AUDIO_CONFIG_BYTE2_REG,config_byte2_reg);/*向偏移地址0x26地址写入config_byte2_reg的值*/if (ret < 0)goto out;ret = regmap_write(sii902x->regmap, SII902X_TPI_I2S_INPUT_CONFIG_REG,i2s_config_reg);/*向I2S输入配置寄存器(地址为0x20)写入i2s_config_reg的值*/if (ret)goto out;for (i = 0; i < ARRAY_SIZE(sii902x->audio.i2s_fifo_sequence) &&sii902x->audio.i2s_fifo_sequence[i]; i++)regmap_write(sii902x->regmap,SII902X_TPI_I2S_ENABLE_MAPPING_REG,sii902x->audio.i2s_fifo_sequence[i]);/*向Audio配置寄存器(起始地址为0x1F)写入sii902x->audio.i2s_fifo_sequence[i]的值*/ret = regmap_write(sii902x->regmap, SII902X_TPI_AUDIO_CONFIG_BYTE3_REG,config_byte3_reg);/*向"TPI Audio配置寄存器"(地址为0x27)写入config_byte3_reg的值*//*bit5:3为SF[2:0],Audio采样频率SF[2:0]=000b,Audio采样频率参考流头;SF[2:0]=001b,Audio采样频率为32KHz;SF[2:0]=010b,Audio采样频率为44.1KHz;SF[2:0]=011b,Audio采样频率为48KHz;SF[2:0]=100b,Audio采样频率为88.2KHz;SF[2:0]=101b,Audio采样频率为96KHz;SF[2:0]=110b,Audio采样频率为176.4KHz;SF[2:0]=111b,Audio采样频率为192KHz;bit7:6为SS[1:0],Audio采样位数；SS[1:0]=00,Audio采样位数参考流头;SS[1:0]=01,Audio采样位数为16位;SS[1:0]=10,Audio采样位数为20位;SS[1:0]=1q,Audio采样位数为24位;*/if (ret)goto out;ret = regmap_bulk_write(sii902x->regmap, SII902X_TPI_I2S_STRM_HDR_BASE,params->iec.status,min((size_t) SII902X_TPI_I2S_STRM_HDR_SIZE,sizeof(params->iec.status)));/*向设备写入多个寄存器*//*I2S通道状态寄存器起始地址为0x21*//*待数据的首地址为(params->iec.status)*//*写入的字节数量为( min((size_t) SII902X_TPI_I2S_STRM_HDR_SIZE,sizeof(params->iec.status)) )*/if (ret)goto out;ret = hdmi_audio_infoframe_pack(&params->cea, infoframe_buf,sizeof(infoframe_buf));if (ret < 0) {dev_err(dev, "%s: Failed to pack audio infoframe: %d\n",__func__, ret);goto out;}ret = regmap_bulk_write(sii902x->regmap,SII902X_TPI_MISC_INFOFRAME_BASE,infoframe_buf,min(ret, SII902X_TPI_MISC_INFOFRAME_SIZE));/*向设备写入多个寄存器*//*sii902x"TPI杂项信息帧数据寄存器"起始地址为0xBF*//*待数据的首地址为(infoframe_buf)*//*写入的字节数量为( min(ret, SII902X_TPI_MISC_INFOFRAME_SIZE) )*/if (ret)goto out;/* Decode Level 0 Packets */ret = regmap_write(sii902x->regmap, SII902X_IND_SET_PAGE, 0x02);/*向页寄存器(地址为0xBC)写入0x02,选择内部page1*/if (ret)goto out;ret = regmap_write(sii902x->regmap, SII902X_IND_OFFSET, 0x24);/*向变址寄存器(地址为0xBD)写入0x24*/if (ret)goto out;ret = regmap_write(sii902x->regmap, SII902X_IND_VALUE, 0x02);/*由页寄存器和变址寄存器选中的寄存器，即为当前寄存器(其固定地址为0xBE)，即向当前寄存器写入0x02，TPI音频配置*/if (ret)goto out;dev_dbg(dev, "%s: hdmi audio enabled\n", __func__);
out:mutex_unlock(&sii902x->mutex);/*解锁*/if (ret) {clk_disable_unprepare(sii902x->audio.mclk);dev_err(dev, "%s: hdmi audio enable failed: %d\n", __func__,ret);}return ret;
}static void sii902x_audio_shutdown(struct device *dev, void *data)
{struct sii902x *sii902x = dev_get_drvdata(dev);mutex_lock(&sii902x->mutex);/*上锁*/regmap_write(sii902x->regmap, SII902X_TPI_AUDIO_CONFIG_BYTE2_REG,SII902X_TPI_AUDIO_INTERFACE_DISABLE);/*向偏移地址0x26地址写入0x00的值*/mutex_unlock(&sii902x->mutex);/*解锁*/clk_disable_unprepare(sii902x->audio.mclk);
}//函数功能：使音色更柔和
static int sii902x_audio_digital_mute(struct device *dev,void *data, bool enable)
{struct sii902x *sii902x = dev_get_drvdata(dev);mutex_lock(&sii902x->mutex);/*上锁*/sii902x_mute(sii902x, enable);/*mute=1,修改"TPI Audio配置寄存器(地址为0x26)"的bit4为1,使能乐器声音为柔和的*/mutex_unlock(&sii902x->mutex);/*解锁*/return 0;
}static int sii902x_audio_get_eld(struct device *dev, void *data,uint8_t *buf, size_t len)
{struct sii902x *sii902x = dev_get_drvdata(dev);mutex_lock(&sii902x->mutex);/*上锁*/memcpy(buf, sii902x->connector.eld,min(sizeof(sii902x->connector.eld), len));mutex_unlock(&sii902x->mutex);/*解锁*/return 0;
}static int sii902x_audio_get_dai_id(struct snd_soc_component *component,struct device_node *endpoint)
{struct of_endpoint of_ep;int ret;ret = of_graph_parse_endpoint(endpoint, &of_ep);if (ret < 0)return ret;/** HDMI sound should be located at reg = <3>* Return expected DAI index 0.*/if (of_ep.port == SII902X_AUDIO_PORT_INDEX)return 0;return -EINVAL;
}static const struct hdmi_codec_ops sii902x_audio_codec_ops = {.hw_params = sii902x_audio_hw_params,.audio_shutdown = sii902x_audio_shutdown,.digital_mute = sii902x_audio_digital_mute,.get_eld = sii902x_audio_get_eld,.get_dai_id = sii902x_audio_get_dai_id,
};static int sii902x_audio_codec_init(struct sii902x *sii902x,struct device *dev)
{static const u8 audio_fifo_id[] = {SII902X_TPI_I2S_CONFIG_FIFO0,SII902X_TPI_I2S_CONFIG_FIFO1,SII902X_TPI_I2S_CONFIG_FIFO2,SII902X_TPI_I2S_CONFIG_FIFO3,};static const u8 i2s_lane_id[] = {SII902X_TPI_I2S_SELECT_SD0,SII902X_TPI_I2S_SELECT_SD1,SII902X_TPI_I2S_SELECT_SD2,SII902X_TPI_I2S_SELECT_SD3,};struct hdmi_codec_pdata codec_data = {.ops = &sii902x_audio_codec_ops,.i2s = 1, /* Only i2s support for now. */.spdif = 0,.max_i2s_channels = 0,};u8 lanes[4];int num_lanes, i;if (!of_property_read_bool(dev->of_node, "#sound-dai-cells")) {dev_dbg(dev, "%s: No \"#sound-dai-cells\", no audio\n",__func__);return 0;}num_lanes = of_property_read_variable_u8_array(dev->of_node,"sil,i2s-data-lanes",lanes, 1,ARRAY_SIZE(lanes));if (num_lanes == -EINVAL) {dev_dbg(dev,"%s: No \"sil,i2s-data-lanes\", use default <0>\n",__func__);num_lanes = 1;lanes[0] = 0;} else if (num_lanes < 0) {dev_err(dev,"%s: Error gettin \"sil,i2s-data-lanes\": %d\n",__func__, num_lanes);return num_lanes;}codec_data.max_i2s_channels = 2 * num_lanes;for (i = 0; i < num_lanes; i++)sii902x->audio.i2s_fifo_sequence[i] |= audio_fifo_id[i] |i2s_lane_id[lanes[i]] |	SII902X_TPI_I2S_FIFO_ENABLE;sii902x->audio.mclk = devm_clk_get_optional(dev, "mclk");if (IS_ERR(sii902x->audio.mclk)) {dev_err(dev, "%s: No clock (audio mclk) found: %ld\n",__func__, PTR_ERR(sii902x->audio.mclk));return PTR_ERR(sii902x->audio.mclk);}sii902x->audio.pdev = platform_device_register_data(dev, HDMI_CODEC_DRV_NAME, PLATFORM_DEVID_AUTO,&codec_data, sizeof(codec_data));return PTR_ERR_OR_ZERO(sii902x->audio.pdev);
}static const struct regmap_range sii902x_volatile_ranges[] = {{ .range_min = 0, .range_max = 0xff },
};static const struct regmap_access_table sii902x_volatile_table = {.yes_ranges = sii902x_volatile_ranges,.n_yes_ranges = ARRAY_SIZE(sii902x_volatile_ranges),
};static const struct regmap_config sii902x_regmap_config = {.reg_bits = 8,.val_bits = 8,.disable_locking = true, /* struct sii902x mutex should be enough */.max_register = SII902X_TPI_MISC_INFOFRAME_END,.volatile_table = &sii902x_volatile_table,.cache_type = REGCACHE_NONE,
};//函数功能：sii902x中断服务程序
static irqreturn_t sii902x_interrupt(int irq, void *data)
{struct sii902x *sii902x = data;unsigned int status = 0;mutex_lock(&sii902x->mutex);/*上锁*/regmap_read(sii902x->regmap, SII902X_INT_STATUS, &status);/*读寄存器地址为0x3D的值，返回值保存到status中"*/regmap_write(sii902x->regmap, SII902X_INT_STATUS, status);/*向偏移地址0x3D地址写入status的值*/mutex_unlock(&sii902x->mutex);/*解锁*/if ((status & SII902X_HOTPLUG_EVENT) && sii902x->bridge.dev)drm_helper_hpd_irq_event(sii902x->bridge.dev);return IRQ_HANDLED;
}/** The purpose of sii902x_i2c_bypass_select is to enable the pass through* mode of the HDMI transmitter. Do not use regmap from within this function,* only use sii902x_*_unlocked functions to read/modify/write registers.* We are holding the parent adapter lock here, keep this in mind before* adding more i2c transactions.** Also, since SII902X_SYS_CTRL_DATA is used with regmap_update_bits elsewhere* in this driver, we need to make sure that we only touch 0x1A[2:1] from* within sii902x_i2c_bypass_select and sii902x_i2c_bypass_deselect, and that* we leave the remaining bits as we have found them.*/
static int sii902x_i2c_bypass_select(struct i2c_mux_core *mux, u32 chan_id)
{struct sii902x *sii902x = i2c_mux_priv(mux);struct device *dev = &sii902x->i2c->dev;unsigned long timeout;u8 status;int ret;ret = sii902x_update_bits_unlocked(sii902x->i2c, SII902X_SYS_CTRL_DATA,SII902X_SYS_CTRL_DDC_BUS_REQ,SII902X_SYS_CTRL_DDC_BUS_REQ);/*通过I2C，修改地址为0x1A寄存器中的bit2,将bit2置1*//*主机请求使用DDC*/if (ret)return ret;timeout = jiffies + msecs_to_jiffies(SII902X_I2C_BUS_ACQUISITION_TIMEOUT_MS);/*修改后的超时时间，打算延时500ms*/do {ret = sii902x_read_unlocked(sii902x->i2c, SII902X_SYS_CTRL_DATA,&status);/*通过I2C读取地址为0x1A寄存器的值，返回值在status中*/if (ret)return ret;} while (!(status & SII902X_SYS_CTRL_DDC_BUS_GRTD) &&time_before(jiffies, timeout));
/*time_before(),如果jiffies<timeout，没有超过预设的系统节拍数，time_before()返回真；*/if (!(status & SII902X_SYS_CTRL_DDC_BUS_GRTD)) {dev_err(dev, "Failed to acquire the i2c bus\n");return -ETIMEDOUT;}return sii902x_write_unlocked(sii902x->i2c, SII902X_SYS_CTRL_DATA,status);/*通过I2C，将status的值写入地址为Ox1A的寄存器中*/
}/** The purpose of sii902x_i2c_bypass_deselect is to disable the pass through* mode of the HDMI transmitter. Do not use regmap from within this function,* only use sii902x_*_unlocked functions to read/modify/write registers.* We are holding the parent adapter lock here, keep this in mind before* adding more i2c transactions.** Also, since SII902X_SYS_CTRL_DATA is used with regmap_update_bits elsewhere* in this driver, we need to make sure that we only touch 0x1A[2:1] from* within sii902x_i2c_bypass_select and sii902x_i2c_bypass_deselect, and that* we leave the remaining bits as we have found them.*/
static int sii902x_i2c_bypass_deselect(struct i2c_mux_core *mux, u32 chan_id)
{struct sii902x *sii902x = i2c_mux_priv(mux);struct device *dev = &sii902x->i2c->dev;unsigned long timeout;unsigned int retries;u8 status;int ret;/** When the HDMI transmitter is in pass through mode, we need an* (undocumented) additional delay between STOP and START conditions* to guarantee the bus won't get stuck.*/udelay(30);/** Sometimes the I2C bus can stall after failure to use the* EDID channel. Retry a few times to see if things clear* up, else continue anyway.*/retries = 5;do {ret = sii902x_read_unlocked(sii902x->i2c, SII902X_SYS_CTRL_DATA,&status);/*通过I2C读取地址为reg寄存器的值，返回值在status中*/retries--;} while (ret && retries);if (ret) {dev_err(dev, "failed to read status (%d)\n", ret);return ret;}ret = sii902x_update_bits_unlocked(sii902x->i2c, SII902X_SYS_CTRL_DATA,SII902X_SYS_CTRL_DDC_BUS_REQ |SII902X_SYS_CTRL_DDC_BUS_GRTD, 0);/*通过I2C，修改地址为0x1A寄存器中的bit2和bit1,将bit2和bit1置0*//*bit2置0主机不使用DDC，bit1置0表示主机不使用总线*/if (ret)return ret;timeout = jiffies + msecs_to_jiffies(SII902X_I2C_BUS_ACQUISITION_TIMEOUT_MS);/*修改后的超时时间，打算延时500ms*/do {ret = sii902x_read_unlocked(sii902x->i2c, SII902X_SYS_CTRL_DATA,&status);/*通过I2C读取地址为0x1A寄存器的值，返回值在status中*/if (ret)return ret;} while (status & (SII902X_SYS_CTRL_DDC_BUS_REQ |SII902X_SYS_CTRL_DDC_BUS_GRTD) &&time_before(jiffies, timeout));/*time_before(),如果jiffies<timeout，没有超过预设的系统节拍数，time_before()返回真；*/if (status & (SII902X_SYS_CTRL_DDC_BUS_REQ |SII902X_SYS_CTRL_DDC_BUS_GRTD)) {dev_err(dev, "failed to release the i2c bus\n");return -ETIMEDOUT;}return 0;
}static const struct drm_bridge_timings default_sii902x_timings = {.input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE| DRM_BUS_FLAG_SYNC_SAMPLE_NEGEDGE| DRM_BUS_FLAG_DE_HIGH,
};/*
函数功能: i2c驱动的probe函数，当驱动与设备匹配以后,此函数就会执行
参数client : i2c设备
参数id : i2c设备ID
返回值: 0，成功;其他负值,失败
*/
static int sii902x_probe(struct i2c_client *client,const struct i2c_device_id *id)
{struct device *dev = &client->dev;unsigned int status = 0;struct sii902x *sii902x;unsigned char data[2] = { SII902X_CEC_SETUP, 0};struct i2c_msg msg = {.addr	= SII902X_CEC_I2C_ADDR << 1,/*sii902x的I2X地址*/.flags	= 0,/*标记为发送数据*/.len	= 2,/*data[]为2个字节*/.buf	= data,/*待写入的数据*/};u8 chipid[4];int ret;ret = i2c_check_functionality(client->adapter,I2C_FUNC_SMBUS_BYTE_DATA);/*如果适配器支持我们需要的一切，则返回1，否则返回0*/if (!ret) {dev_err(dev, "I2C adapter not suitable\n");return -EIO;}sii902x = devm_kzalloc(dev, sizeof(*sii902x), GFP_KERNEL);/*向内核申请一块内存，当设备驱动程序被卸载时，内存会被自动释放*/if (!sii902x)return -ENOMEM;sii902x->i2c = client;sii902x->regmap = devm_regmap_init_i2c(client, &sii902x_regmap_config);/*创建regmap实例*/if (IS_ERR(sii902x->regmap))return PTR_ERR(sii902x->regmap);sii902x->reset_gpio = devm_gpiod_get_optional(dev, "reset",GPIOD_OUT_LOW);/*用于获取可选的GPIO设备。它是Linux内核中的一个函数，用于在设备树中查找GPIO设备，并返回一个GPI0描述符。如果找不到GPIO设备，则返回NULL。该函数使用devm_前缀，表示它是一个设备管理函数，可以自动释放资源。*/if (IS_ERR(sii902x->reset_gpio)) {dev_err(dev, "Failed to retrieve/request reset gpio: %ld\n",PTR_ERR(sii902x->reset_gpio));return PTR_ERR(sii902x->reset_gpio);}mutex_init(&sii902x->mutex);/*初始化互斥体*/sii902x->supplies[0].supply = "iovcc";sii902x->supplies[1].supply = "cvcc12";ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(sii902x->supplies),sii902x->supplies);/*用于在设备驱动程序中获取组相关的稳压器。这个函数使用设备管理器(devm)机制，因此可以确保在设备被释放时自动注销稳压器。这个函数需要传入一个指向设备结构体的指针、一个指向稳压器结构体数组的指针、以及数组中稳压器的数量。函数返回一个整数值，表示成功获取的稳压器数量。如果返回的值与期望值不同，则表示出现了错误。*/if (ret) {if(ret != -EPROBE_DEFER)dev_err(dev, "regulator_bulk_get failed\n");return ret;}ret = regulator_bulk_enable(ARRAY_SIZE(sii902x->supplies),sii902x->supplies);if (ret) {dev_err(dev, "regulator_bulk_enable failed\n");return ret;}sii902x_reset(sii902x);/*sii902复位*/ret = regmap_write(sii902x->regmap, SII902X_REG_TPI_RQB, 0x0);/*硬件复位第1步，向偏移地址0xC7地址写入0x00*/if (ret)goto err_disable_regulator;ret = regmap_bulk_read(sii902x->regmap, SII902X_REG_CHIPID(0),&chipid, 4);/*读芯片的ID和版本；地址范围0x1B～0x1D，保存的是TPI芯片的ID和版本*/if (ret) {dev_err(dev, "regmap_read failed %d\n", ret);goto err_disable_regulator;}if (chipid[0] != 0xb0) {dev_err(dev, "Invalid chipid: %02x (expecting 0xb0)\n",chipid[0]);ret = -EINVAL;goto err_disable_regulator;}/** By default, CEC must be disabled to allow other CEC devives* to bypass the bridge.*/ret = i2c_transfer(client->adapter, &msg, 1);/*发送“sii902x地址“，发送“要写入数据的寄存器首地址“，接着写入“该寄存器的数据“*//*因为只有“一条写消息“，因此消息数量为1*/if (ret < 0)dev_warn(&client->dev, "Failed to disable CEC device!\n");/* Clear all pending interrupts */regmap_read(sii902x->regmap, SII902X_INT_STATUS, &status);/*读寄存器地址为0x3D的值，返回值保存到status中"*/regmap_write(sii902x->regmap, SII902X_INT_STATUS, status);/*向寄存器地址为0x3D中写入"TPI中断状态值"*/if (client->irq > 0) {regmap_update_bits(sii902x->regmap, SII902X_INT_ENABLE,SII902X_HOTPLUG_EVENT,SII902X_HOTPLUG_EVENT);/*修改"中断使能寄存器"的bit0为1，使能中断引脚输出*/ret = devm_request_threaded_irq(dev, client->irq, NULL,sii902x_interrupt,IRQF_ONESHOT, dev_name(dev),sii902x);/*注册中断处理程序，且中断线程化，并具有自动资源管理的功能。*/if (ret)goto err_disable_regulator;}sii902x->bridge.funcs = &sii902x_bridge_funcs;sii902x->bridge.of_node = dev->of_node;sii902x->bridge.timings = &default_sii902x_timings;drm_bridge_add(&sii902x->bridge);sii902x_audio_codec_init(sii902x, dev);i2c_set_clientdata(client, sii902x);/*将sii902x变量的地址绑定client*//*就可以通过i2c_get_clientdata(client)获取sii902x变量指针*/sii902x->i2cmux = i2c_mux_alloc(client->adapter, dev,1, 0, I2C_MUX_GATE,sii902x_i2c_bypass_select,sii902x_i2c_bypass_deselect);if (!sii902x->i2cmux)return -ENOMEM;sii902x->i2cmux->priv = sii902x;ret = i2c_mux_add_adapter(sii902x->i2cmux, 0, 0, 0);if (ret) {dev_err(dev, "Couldn't add i2c mux adapter\n");return ret;}return 0;err_disable_regulator:regulator_bulk_disable(ARRAY_SIZE(sii902x->supplies),sii902x->supplies);return ret;
}/*sii902x驱动的remove函数 */
static int sii902x_remove(struct i2c_client *client){struct sii902x *sii902x = i2c_get_clientdata(client);/*通过i2c_get_clientdata(client)获取sii902x变量的指针值*/i2c_mux_del_adapters(sii902x->i2cmux);drm_bridge_remove(&sii902x->bridge);regulator_bulk_disable(ARRAY_SIZE(sii902x->supplies),sii902x->supplies);return 0;
}static int sii902x_pm_suspend(struct device *dev)
{struct i2c_client *client = to_i2c_client(dev);struct sii902x *sii902x = i2c_get_clientdata(client);/*通过i2c_get_clientdata(client)获取sii902x变量的指针值*/DRM_DEBUG_DRIVER("\n");if (sii902x->reset_gpio)gpiod_set_value(sii902x->reset_gpio, 1);/*1表示设置引脚输出高电平*/regulator_bulk_disable(ARRAY_SIZE(sii902x->supplies),sii902x->supplies);return 0;
}static int sii902x_pm_resume(struct device *dev)
{struct i2c_client *client = to_i2c_client(dev);struct sii902x *sii902x = i2c_get_clientdata(client);/*通过i2c_get_clientdata(client)获取sii902x变量的指针值*/unsigned char data[2] = { SII902X_CEC_SETUP, 0};struct i2c_msg msg = {.addr	= SII902X_CEC_I2C_ADDR << 1,/*sii902x的I2X地址*/.flags	= 0,/*标记为发送数据*/.len	= 2,/*data[]为2个字节*/.buf	= data,/*待写入的数据*/};int ret;DRM_DEBUG_DRIVER("\n");ret = regulator_bulk_enable(ARRAY_SIZE(sii902x->supplies),sii902x->supplies);if (ret) {DRM_ERROR("regulator_bulk_enable failed\n");return ret;}if (sii902x->reset_gpio)gpiod_set_value(sii902x->reset_gpio, 0);/*0表示设置引脚输出低电平*/regmap_write(sii902x->regmap, SII902X_REG_TPI_RQB, 0x00);/*向偏移地址0xC7地址写入0x00的值*/ret = i2c_transfer(client->adapter, &msg, 1);/*发送“sii902x地址“，发送“要写入数据的寄存器首地址“，接着写入“该寄存器的数据“*//*因为只有“一条写消息“，因此消息数量为1*/if (ret < 0)DRM_ERROR("Failed to disable CEC device!\n");if (client->irq > 0)regmap_update_bits(sii902x->regmap, SII902X_INT_ENABLE,SII902X_HOTPLUG_EVENT,SII902X_HOTPLUG_EVENT);return 0;
}static const struct dev_pm_ops sii902x_pm_ops = {SET_SYSTEM_SLEEP_PM_OPS(sii902x_pm_suspend, sii902x_pm_resume)
};/*设备树匹配表*/
static const struct of_device_id sii902x_dt_ids[] = {{ .compatible = "sil,sii9022", },/*在stm32mp157d-atk.dts设备树文件中，定义“compatible = "sil,sii9022";”*/{/*这是一个空元素,在编写of_device_id时最后一个元素一定要为空*//* sentinel */}
};
MODULE_DEVICE_TABLE(of, sii902x_dt_ids);/*传统匹配方式ID列表*/
static const struct i2c_device_id sii902x_i2c_ids[] = {{ "sii9022", 0 },{ },
};
MODULE_DEVICE_TABLE(i2c, sii902x_i2c_ids);/*初始化i2c_driver结构变量sii902x_driver,i2c驱动结构体 */
static struct i2c_driver sii902x_driver = {.probe = sii902x_probe,/*i2c驱动的probe函数为sii902x_probe()*/.remove = sii902x_remove,/*i2c驱动的remove函数为sii902x_remove()*/.driver = {.name = "sii902x",/* 驱动名字，用于和设备匹配 */.of_match_table = sii902x_dt_ids,/*设备树匹配表*/.pm = &sii902x_pm_ops,},.id_table = sii902x_i2c_ids,/*传统匹配方式ID列表*/
};
module_i2c_driver(sii902x_driver);MODULE_AUTHOR("Boris Brezillon <boris.brezillon@free-electrons.com>");//添加作者名字
MODULE_DESCRIPTION("SII902x RGB -> HDMI bridges");//模块介绍
MODULE_LICENSE("GPL");//LICENSE采用“GPL协议”

7、测试结果

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