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 0x8e
struct 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;
else
sii902x->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;
else
i2s_config_reg |= SII902X_TPI_I2S_SCK_EDGE_RISING;
if (daifmt->frame_clk_inv)
i2s_config_reg |= SII902X_TPI_I2S_WS_POLARITY_LOW;
else
i2s_config_reg |= SII902X_TPI_I2S_WS_POLARITY_HIGH;
if (params->channels > 2)
config_byte2_reg |= SII902X_TPI_AUDIO_LAYOUT_8_CHANNELS;
else
config_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(¶ms->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
略
