STRUCT CDNS_I2C(9)

💅 struct cdns_i2c(9) — I2C device private data structure 🎀

okay bestie, welcome to the struct cdns_i2c(9) page from the Kernel API Manual ✨ we are in section 9, deep in kernel territory, and this is the I2C device private data structure. it's giving backstage-pass energy, and we are obsessed 💖 no field left behind, periodt.

✨ NAME ✨

struct cdns_i2c — I2C device private data structure 🌸

🦋 SYNOPSIS 🦋

       struct cdns_i2c {
           struct device           *dev;
           void __iomem *membase;
           struct i2c_adapter adap;
           struct i2c_msg *p_msg;
           int err_status;
           struct completion xfer_done;
           unsigned char *p_send_buf;
           unsigned char *p_recv_buf;
           unsigned int send_count;
           unsigned int recv_count;
           unsigned int curr_recv_count;
           unsigned long input_clk;
           unsigned int i2c_clk;
           unsigned int bus_hold_flag;
           struct clk *clk;
           struct notifier_block clk_rate_change_nb;
           struct reset_control *reset;
           u32 quirks;
           u32 ctrl_reg;
           struct i2c_bus_recovery_info rinfo;
         #if IS_ENABLED(CONFIG_I2C_SLAVE);
           u16 ctrl_reg_diva_divb;
           struct i2c_client *slave;
           enum cdns_i2c_mode dev_mode;
           enum cdns_i2c_slave_state slave_state;
         #endif;
           u32 fifo_depth;
           unsigned int transfer_size;
           bool atomic;
           int err_status_atomic;
        };

here's the whole struct in all its glory, bestie — read it like a group-chat screenshot 🫶 now let's meet every member one by one.

🎀 Members 🎀

• dev — pointer to the device structure 🏠
• membase — base address of the I2C device 📍
• adap — I2C adapter instance 🔌
• p_msg — message pointer 💌
• err_status — error status in Interrupt Status Register 😭
• xfer_done — transfer complete status ✅
• p_send_buf — pointer to transmit buffer 📤
• p_recv_buf — pointer to receive buffer 📥
• send_count — number of bytes still expected to send 🔢
• recv_count — number of bytes still expected to receive 🧮
• curr_recv_count — number of bytes to be received in current transfer 🎯
• input_clk — input clock to I2C controller ⏰
• i2c_clk — maximum I2C clock speed 🚀
• bus_hold_flag — flag used in repeated start for clearing HOLD bit ✋
• clk — pointer to struct clk 🕰️
• clk_rate_change_nb — notifier block for clock rate changes 🔔
• reset — reset control for the device 🔄
• quirks — flag for broken hold bit usage in r1p10 🚩
• ctrl_reg — cached value of the control register. 📝
• rinfo — I2C GPIO recovery information 🛟
• ctrl_reg_diva_divb — value of fields DIV_A and DIV_B from CR register 🧮
• slave — registered slave instance. 🤝
• dev_mode — I2C operating role(master/slave). 👑
• slave_state — I2C Slave state(idle/read/write). 💤
• fifo_depth — the depth of the transfer FIFO 🧺
• transfer_size — the maximum number of bytes in one transfer 📏
• atomic — mode of transfer ⚛️
• err_status_atomic — error status in atomic mode 💥

🌈 SEE ALSO 🌈

kernel file: ./drivers/i2c/busses/i2c-cadence.c 📁

• enum cdns_i2c_mode(9)
• enum cdns_i2c_slave_state(9)
• cdns_i2c_init(9)
• cdns_i2c_runtime_suspend(9)
• cdns_i2c_runtime_resume(9)
• cdns_i2c_clear_bus_hold(9)
• cdns_i2c_slave_isr(9)
• cdns_i2c_master_isr(9)
• cdns_i2c_isr(9)
• cdns_i2c_mrecv(9)
• cdns_i2c_msend(9)
• cdns_i2c_master_reset(9)
• cdns_i2c_master_xfer(9)
• cdns_i2c_master_xfer_atomic(9)
• cdns_i2c_func(9)
• cdns_i2c_calc_divs(9)
• cdns_i2c_setclk(9)
• cdns_i2c_clk_notifier_cb(9)
• cdns_i2c_detect_transfer_size(9)
• cdns_i2c_probe(9)
• cdns_i2c_remove(9)
• cdns_i2c_shutdown(9)

mwah 💋 this page came from ./drivers/i2c/busses, dated October 2026, and it's the struct cdns_i2c(9) manpage from the Kernel API Manual — byeee, go read some kernel source for me 💜✨