/* SPDX-License-Identifier: GPL-2.0-only */ #include <device/mmio.h> #include <assert.h> #include <console/console.h> #include <delay.h> #include <device/i2c_simple.h> #include <soc/addressmap.h> #include <soc/grf.h> #include <soc/soc.h> #include <soc/i2c.h> #include <soc/clock.h> #include <stddef.h> #include <stdint.h> #define RETRY_COUNT 3 /* 100000us = 100ms */ #define I2C_TIMEOUT_US 100000 #define I2C_BUS_MAX 6 #define I2C_NOACK 2 #define I2C_TIMEOUT 3 #define i2c_info(x...) do {if (0) printk(BIOS_DEBUG, x); } while (0) struct rk_i2c_regs { u32 i2c_con; u32 i2c_clkdiv; u32 i2c_mrxaddr; u32 i2c_mrxraddr; u32 i2c_mtxcnt; u32 i2c_mrxcnt; u32 i2c_ien; u32 i2c_ipd; u32 i2c_fcnt; u32 reserved0[(0x100 - 0x24) / 4]; u32 txdata[8]; u32 reserved1[(0x200 - 0x120) / 4]; u32 rxdata[8]; }; static const uintptr_t i2c_bus[] = IC_BASES; /* Con register bits. */ #define I2C_ACT2NAK (1<<6) #define I2C_NAK (1<<5) #define I2C_STOP (1<<4) #define I2C_START (1<<3) #define I2C_MODE_TX (0<<1) #define I2C_MODE_TRX (1<<1) #define I2C_MODE_RX (2<<1) #define I2C_EN (1<<0) #define I2C_8BIT (1<<24) #define I2C_16BIT (3<<24) #define I2C_24BIT (7<<24) /* Mtxcnt register bits. */ #define I2C_CNT(cnt) ((cnt) & 0x3F) #define I2C_NAKRCVI (1<<6) #define I2C_STOPI (1<<5) #define I2C_STARTI (1<<4) #define I2C_MBRFI (1<<3) #define I2C_MBTFI (1<<2) #define I2C_BRFI (1<<1) #define I2C_BTFI (1<<0) #define I2C_CLEANI 0x7F static int i2c_send_start(struct rk_i2c_regs *reg_addr) { int res = 0; int timeout = I2C_TIMEOUT_US; i2c_info("I2c Start::Send Start bit\n"); write32(®_addr->i2c_ipd, I2C_CLEANI); write32(®_addr->i2c_con, I2C_EN | I2C_START); while (timeout--) { if (read32(®_addr->i2c_ipd) & I2C_STARTI) break; udelay(1); } if (timeout <= 0) { printk(BIOS_ERR, "I2C Start::Send Start Bit Timeout\n"); res = I2C_TIMEOUT; } return res; } static int i2c_send_stop(struct rk_i2c_regs *reg_addr) { int res = 0; int timeout = I2C_TIMEOUT_US; i2c_info("I2c Stop::Send Stop bit\n"); write32(®_addr->i2c_ipd, I2C_CLEANI); write32(®_addr->i2c_con, I2C_EN | I2C_STOP); while (timeout--) { if (read32(®_addr->i2c_ipd) & I2C_STOPI) break; udelay(1); } write32(®_addr->i2c_con, 0); if (timeout <= 0) { printk(BIOS_ERR, "I2C Stop::Send Stop Bit Timeout\n"); res = I2C_TIMEOUT; } return res; } static int i2c_read(struct rk_i2c_regs *reg_addr, struct i2c_msg segment) { int res = 0; uint8_t *data = segment.buf; unsigned int bytes_remaining = segment.len; unsigned int con = 0; write32(®_addr->i2c_mrxaddr, I2C_8BIT | segment.slave << 1 | 1); write32(®_addr->i2c_mrxraddr, 0); con = I2C_MODE_TRX | I2C_EN | I2C_ACT2NAK; while (bytes_remaining) { int timeout = CONFIG_I2C_TRANSFER_TIMEOUT_US; size_t size = MIN(bytes_remaining, 32); bytes_remaining -= size; if (!bytes_remaining) con |= I2C_EN | I2C_NAK; i2c_info("I2C Read::%zu bytes\n", size); write32(®_addr->i2c_ipd, I2C_CLEANI); write32(®_addr->i2c_con, con); write32(®_addr->i2c_mrxcnt, size); while (timeout--) { if (read32(®_addr->i2c_ipd) & I2C_NAKRCVI) { write32(®_addr->i2c_mrxcnt, 0); write32(®_addr->i2c_con, 0); return I2C_NOACK; } if (read32(®_addr->i2c_ipd) & I2C_MBRFI) break; udelay(1); } if (timeout <= 0) { printk(BIOS_ERR, "I2C Read::Recv Data Timeout\n"); write32(®_addr->i2c_mrxcnt, 0); write32(®_addr->i2c_con, 0); return I2C_TIMEOUT; } buffer_from_fifo32(data, size, ®_addr->rxdata, 4, 4); data += size; con = I2C_MODE_RX | I2C_EN | I2C_ACT2NAK; } return res; } static int i2c_write(struct rk_i2c_regs *reg_addr, struct i2c_msg segment) { int res = 0; uint8_t *data = segment.buf; int bytes_remaining = segment.len + 1; /* Prepend one byte for the slave address to the transfer. */ u32 prefix = segment.slave << 1; int prefsz = 1; while (bytes_remaining) { int timeout = CONFIG_I2C_TRANSFER_TIMEOUT_US; size_t size = MIN(bytes_remaining, 32); buffer_to_fifo32_prefix(data, prefix, prefsz, size, ®_addr->txdata, 4, 4); data += size - prefsz; i2c_info("I2C Write::%zu bytes\n", size); write32(®_addr->i2c_ipd, I2C_CLEANI); write32(®_addr->i2c_con, I2C_EN | I2C_MODE_TX | I2C_ACT2NAK); write32(®_addr->i2c_mtxcnt, size); while (timeout--) { if (read32(®_addr->i2c_ipd) & I2C_NAKRCVI) { write32(®_addr->i2c_mtxcnt, 0); write32(®_addr->i2c_con, 0); return I2C_NOACK; } if (read32(®_addr->i2c_ipd) & I2C_MBTFI) break; udelay(1); } if (timeout <= 0) { printk(BIOS_ERR, "I2C Write::Send Data Timeout\n"); write32(®_addr->i2c_mtxcnt, 0); write32(®_addr->i2c_con, 0); return I2C_TIMEOUT; } bytes_remaining -= size; prefsz = 0; prefix = 0; } return res; } static int i2c_do_xfer(void *reg_addr, struct i2c_msg segment) { int res = 0; if (i2c_send_start(reg_addr)) return I2C_TIMEOUT; if (segment.flags & I2C_M_RD) res = i2c_read(reg_addr, segment); else res = i2c_write(reg_addr, segment); return i2c_send_stop(reg_addr) || res; } int platform_i2c_transfer(unsigned int bus, struct i2c_msg *segments, int seg_count) { int i; int res = 0; struct rk_i2c_regs *regs = (struct rk_i2c_regs *)(i2c_bus[bus]); struct i2c_msg *seg = segments; for (i = 0; i < seg_count; i++, seg++) { res = i2c_do_xfer(regs, *seg); if (res) break; } return res; } void i2c_init(unsigned int bus, unsigned int hz) { unsigned int clk_div; unsigned int divl; unsigned int divh; unsigned int i2c_src_clk; unsigned int i2c_clk; struct rk_i2c_regs *regs = (struct rk_i2c_regs *)(i2c_bus[bus]); i2c_src_clk = rkclk_i2c_clock_for_bus(bus); /* SCL Divisor = 8*(CLKDIVL + 1 + CLKDIVH + 1) SCL = PCLK / SCLK Divisor */ clk_div = DIV_ROUND_UP(i2c_src_clk, hz * 8); divh = clk_div * 3 / 7 - 1; divl = clk_div - divh - 2; i2c_clk = i2c_src_clk / (8 * (divl + 1 + divh + 1)); printk(BIOS_DEBUG, "I2C bus %u: %uHz (divh = %u, divl = %u)\n", bus, i2c_clk, divh, divl); assert((divh < 65536) && (divl < 65536) && hz - i2c_clk < 15*KHz); write32(®s->i2c_clkdiv, (divh << 16) | (divl << 0)); }